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Report 00t �.� Stormwater Management Plan 1 The Fields Apartments ' Tigard, Oregon February 26, 2018 1 Prepared for: DBG Properties, LLC Prepared by: Otak, Inc. Rose Horton, PE Water Resources Engineer Jeremy Tamargo, PE t 9 Water Resources Engineer 1 Otak I I I Stormwater Management Plan The Fields Apartments Tigard, Oregon IPROJECT SUMMARY Date: February 26, 2018 I Washington County Casefile: Clean Water Services SPL 17-002878 IDelineation #: Project Type: Residential Development IProject Location: Tigard, Oregon I Latitude/Longitude: 45° 25' 26" N; 122°45' 27"W Plan Prepared By: Otak, Inc. City of Tigard, 1998. Public Improvement Design Standards. I Stormwater Manuals Cited: Clean Water Services, 2017. Design and Construction Standards for Sanitary Sewer and Surface Water Management. IClean Water Services, 2016. Low Impact Development Approaches Handbook. iUnited States Army Corps of Engineers, 2014. SLOPES V for Stormwater, Transportation or Utilities. I I I I 1 I I IThe Fields Apartments i :IProject1170001170521Reports\Stormwater Management PlanI17052_SWMP final_02-26-18.docx otak Table of Contents IPage Introduction 1 Site Description 1 Drainage Basins 2 IExisting Conditions 2 Proposed Conditions 2 IHydrology 3 Soils 3 Curve Number 4 I Time of Concentration 4 Water Quality 4 I Private Development 4 Public Right-of-Way 5 I Water Quantity 5 Conveyance 8 Inlet Capacity Check 8 1 Operations and Maintenance 9 Conclusions 9 IReferences 9 tTables Table 1: Proposed Drainage Basin Areas Summary 3 1 Table 2: Precipitation Depths 3 Table 3: Runoff Curve Numbers 4 I Table 4: Facility Flow Control Summary 6 Table 5: Underground Detention System Design Parameters 6 ITable 6—Flow Control Structure Summary: North 7 Table 7— Flow Control Structure Summary: South Residential 7 I Table 8—Flow Control Structure Summary: Employment 7 Table 9— Flow Control Structure Summary: Wall 7 Table 10—Water Surface Elevations and Detention Volumes: North 7 ITable 11 —Water Surface Elevations and Detention Volumes: South Residential 8 Table 12—Water Surface Elevations and Detention Volumes: Employment 8 ITable 13—Water Surface Elevations and Detention Volumes: Wall 8 The Fields Apartments ii LIP roject1170001170521Reports1Stormwater Management PIan117052_SWMP_final_02-26-18.docx otak I Table of Contents Figures Figure 1: Existing Drainage Conditions Figure 2: Proposed Drainage Conditions Figure 3: Proposed Drainage Conditions- Subbasins Appendices Appendix A: Hydrology I Appendix B: Water Quality Calculations Appendix C: HydroCAD Output Appendix D: XP-SWMM Output Appendix E: Inlet Capacity Calculations Appendix F: Operations and Maintenance Plan Appendix G: Plan Sheets I 1 1 I 1 1 The Fields Apartments L:IProject1170001170521Reports\Stormwater Management PIanI17052_SWMP_final_02-26-18.docx otak Stormwater Management Plan IIntroduction I The Fields Apartments project is a proposed multi-family residential development in the City of Tigard, with stormwater jurisdiction through Clean Water Services (CWS). The development will consist of five multi-family residential buildings, a club house and parking. The development also includes sidewalks, public roadway I improvements, private driveways, utilities, and a stormwater management system. The stormwater management system will include a conveyance system, low impact development approaches (LIDA)for stormwater treatment, a detention pond, and underground detention facilities. Additionally, this project impacts wetlands, which requires I stormwater management to be compliant with SLOPES V for Stormwater Transportation or Utilities(SLOPES V) standards. The purpose of this document is to outline compliance of the Fields Apartments stormwater management system Iwith Clean Water Services' Design and Construction Standards for Sanitary Sewer and Surface Water Management(CWS, 2017)and U.S. Army Corps of Engineers SLOPES V for Stormwater, Transportation or Utilities(USACOE, 2014). Descriptions of the pre-developed, existing and proposed (post-developed) hydrologic I conditions, as well as documentation showing the onsite stormwater management system's compliance with CWS and SLOPES V standards for water quality and quantity are included in this report. The future phase of the development project will be the employment development located directly south of the residential development. IPreliminary design of the employment stormwater system is included for reference. Site Description IThe 14.91-acre Fields Apartment site is within the limits of the City of Tigard. The site is located southeast of the intersection of SW Hunziker Steet and SW Wall Street, with railroad bordering the future employment site to the I south (see Vicinity Map). The private portion of the site consists of tax lot 251010001600. The private property is currently undeveloped, with forest, shrubby, and grass cover. Redrock Creek, tributary to Fanno Creek, runs west of the property. Wetland delineation verified the presence of small wetland areas in the southwestern corner of I the site (see Figure 1). The area of impact for this proposed development is located outside of the FEMA base flood area (see Appendix A for the FEMA FIRMette). I I I I I I I The Fields Apartments I 1 :\Project117000\170521Reports\Stormwater Management PIan117052_SWMP_final_02-26-18.docx otak Stormwater Management Plan I I L(WIE s tome rprovern it i I Redrock Creek i I a The Fields Ptatirld Cl go ,Teo, Apartments ----Nk'. Iif I I4 0.r _.art;t;tri. rt ,brarN ' IWo Future i. Employment Site I I 1 Vicinity Map ' Drainage Basins Existing Conditions I The Fields Apartment property has slopes ranging between 9 to 25%, with stormwater draining northwest to SW Hunziker Street and southwest towards the wetlands, which drain west to Redrock Creek (see Figure 1). The private property is currently undeveloped, with forest, shrubby and grass cover. An access road and concrete pad I are at the south edge of the site in the future Wall Street right-of-way. Runoff from vegetated offsite properties to the east of the site sheet flows onto the site and runoff from a portion of SW Varns Road drains onto the site in a narrow gravel channel. Figure 1 delineates the area potentially served by the project provided storm connection. I The term "existing conditions" refers to the project site der current land use conditions. SLOPES V standards require runoff rates for the pre-developed conditiunon, which is the discharge rate for the site based on its natural groundcover and grade before any development occurred. The pre-developed condition of the site used in ' hydrologic calculations is woods in fair condition. Proposed Conditions ' The residential development will consist of five multi-family residential buildings, a club house, driveway, and parking (see Figure 2). The proposed development calls for the dedication of additional public right-of-way for the widening of SW Hunziker Street along the north frontage of the property and SW Wall Street south of the I property. The development will also dedicate right-of-way for SW 76th Avenue and construct an 8-foot wide concrete path. The proposed residential development will create or replace 6.82 acres of impervious area on The Fields Apartments 2 :1Project1170001170521Reports\Stormwater Management PIan117052_SWMP_final_02-26-18.docx otak Stormwater Management Plan Iprivate property and 1.21 acres in the proposed public right-of-way. Approximately one quarter of the site drains north towards SW Hunziker Street and the remainder drains south towards SW Wall Street. The estimated I impervious areas within the future employment site were included in calculations for the stormwater management system draining south. Pre-application notes require the extension of the public storm sewer to serve the upslope properties to the west at SW Varns Street. A slope easement for the adjacent property extends along the western Iside of the property and disturbance within the easement is limited to a stair connection with the adjacent property. Drainage basin areas for the proposed conditions are summarized in Table 1 and subbasin areas are detailed in Figure 3 and Appendix A. Table 1 Proposed Drainage Basin Areas Summary I Basin Impervious Area (ac) Pervious Area (ac) Total Area (ac)* l Hunziker 0.25 0.26 0.51 North Residential 2.60 3.05 5.65 ISouth Residential 3.62 3.26 6.89 Wall 1.62 3.15 4.77 Future Employment 3.54 1.66 5.20 * Totals reflect rounding from original calculation spreadsheet, see Appendix A. I Hydrology The hydrologic calculations were completed using modeling software programs. The stormwater detention system I for the Fields Apartments project was modeled using HydroCAD v10.0 software, while the conveyance system was modeled in XP-SWMM v2014. The proposed development was divided into pervious and impervious areas for each drainage basin, as shown in Table 1. Peak runoff rates generated from the property were calculated I using the Santa Barbara Urban Hydrograph (SBUH) method in HydroCAD v10.0 and in accordance with Chapter 5 of the CWS design manual. Precipitation depths for this project site, listed in Table 2, were obtained from the CWS design manual, Drawing No. 1280, and were applied to the NRCS Type 1A rainfall distribution. The CWS I precipitation depths are higher than the NOAA 24-hour precipitation depths. Table 2: Precipitation Depths IRecurrence Interval Precipitation Depth (in) 2-Year 2.50 I10-Year 3.45 25-Year 3.90 1 100-Year 4.50 Soils ISoils over most of the site are rated by the National Resource Conservation Service (NRCS)as hydrologic soil group (HSG)C, which consist of Quatama loam and Cornelius and Kinton silt loam. The southern 15% of the site, with in Wall Basin, has Aloha silt loam which is rated as HSG D (See Appendix A). These soils generally exhibit Ilow infiltration rates and relatively high runoff rates. The Fields Apartments 3 IL:1Project117000\170521Reports\Stormwater Management PIan117052_SWMP_final_02-26 18.docx utak I Stormwater Management Plan Curve Number Per CWS standards, Curve Numbers (CN)for impervious and pervious areas during existing and proposed conditions were selected using Table 2-2a—Runoff Curve Numbers for Urban Areas and Table 2-2c-Runoff curve I numbers for Other Agricultural Lands from Technical Release 55: Urban Hydrology for Small Watersheds (TR- 55). SLOPES V requires release rates from detention facilities to match the frequency and duration of flows generated by storms applied to the pre-development site conditions. As such, the project site is modeled using I CNs under pre-development conditions for establishing target flow rates, and CNs reflective of new development for calculating future runoff rates. Table 3 provides a summary of the runoff curve numbers under pre-developed and proposed conditions. The CNs applied to the offsite basin are based on existing conditions. I Table 3: Runoff Curve Numbers Category Cover Type HSG Curve Number I Impervious Area Pavement, roofs, sidewalks C, D 98 Proposed >75% Grass cover-Good Condition* C 74 I Pervious Area 50%-70% Grass cover- Fair Condition D 84 Pre-Developed C 73 I Pervious Area Woods, Fair Condition D 79 * Reflects large undisturbed areas with mature vegetation. I Time of Concentration The time of concentration (Tc)represents the maximum time needed for all areas of the basin to contribute to the I outflow hydrograph. The time of concentration for pre-developed conditions was calculated using the method provided by the Soil Conservation Service (SCS)Technical Release 55 (SCS, 1986), see Appendix A. A time of concentration of five minutes, the minimum allowable, was assumed for all proposed conditions as a conservative I design approach. Water Quality I Per the Oregon Department of Environmental Quality(DEQ) Stormwater Management Plan Submission Guidelines for Removal/Fill Permit Applications, the pollutants of concern for a commercial/residential development are as follows: I • Nutrients • Pesticides, Herbicides, Fungicides ' • ■Metals(Zinc, Copper, Lead, etc.) • Oil, Grease&Other Petroleum • Sediment I CWS Standards require water quality treatment for runoff from contributing impervious areas, generated by 0.36 inches of precipitation falling in a four hour period with a 96-hour return interval. The water quality volume requiring treatment under SLOPES V standards is determined by multiplying 50 percent of the 2-year, 24-hour I precipitation depth by the entire contributing impervious area. Previous conversations with NOAA reviewers have determined that LIDA sized using the CWS sizing factor meet SLOPES V water quality standards. Calculations of water quality volumes are shown in Appendix B. I Private Development Low Impact Development Approach (LIDA)flow-through planters, rain garden, and vegetated filter strip are I proposed for water quality treatment. The vegetated filter strip will treat runoff from the SW 76th Avenue pedestrian path. The rain garden will treat runoff from Residential Building 5. The LIDA flow-through planters will The Fields Apartments 4 I L:1Project1170001170521Reports\Stormwater Management PIan117052_SWMP_fnal_02-26-18.docx otak Stormwater Management Plan treat runoff from the remaining site impervious area, filtering out pollutants by allowing water to filter through vegetation and percolate through the water quality mix and gravel drain rock before being collected into a I perforated underdrain connected to the storm sewer system. Per CWS standards, each LIDA planter is required to have a minimum treatment area equal to six percent of the contributing impervious area, which is accepted to meet SLOPES V standards as well. Due to space constraints, three LIDA planters for the residential development I were sized to 5.4-5.9 percent of the contributing impervious area. These LIDA facilities will be designed with an increased water quality mix depth of 24 inches to provide sufficient treatment within the smaller footprint. Five LIDA facilities are sized to be 10% greater than required. A series of stairs on the west slope connects with the adjacent property to the west of the residential site. It is infeasible to capture and treat runoff from the 0.01 acres of impervious area on site. I Public Right-of-Way Runoff from sidewalks within the right-of-way and the half-street improvement along SW Hunziker Street and three-quarter street improvements along SW Wall Street will drain to LIDA facilities located in the planter strip I between the roadway and the sidewalk. Runoff from approximately 1.19 acres of existing and new impervious area in the public right-of-way will be managed. Slope and space constraints along the SW Hunziker Street west of the site driveway make it infeasible to capture and treat a portion of the runoff draining to SW Hunziker Street I (basin H2). The existing development upslope east of the project site does not include stormwater management. Runoff from ISW Varns Street and two fronting properties will be collected and treated in a rain garden. A simplified approach method was used to size the LIDA facilities, with each facility required to have a minimum treatment area equal to six percent of the contributing impervious area, per CWS standards. Due to open space Iconstraints, four LIDA were only sized to 4.5 percent of the contributing impervious area. These LIDA facilities will be designed with an increased water quality mix depth of 24 inches to provide sufficient treatment within the smaller footprint. IWater Quantity ICWS standards require onsite detention facilities to be designed to detain runoff so that the post-development release rates do not exceed the existing runoff rates from the site for the 2-year, 10-year, and 25-year return Ifrequency storm events. SLOPES V requires flow duration matching, a type of modeling which has not yet been adopted by CWS, for storm event frequencies between 50 percent of the 2-year storm event through the 10-year storm event. I In the absence of an adopted continuous simulation model, a target peak flow matching method was used to approximate the results of the flow duration standard. The target peak flow matching is as follows: • Limit the proposed condition peak rate from the 2-year, 24-hour design storm to match the pre-developed Icondition peak rate from the 2-year, 24-hour design storm. ■ Limit the proposed condition peak rate from the 10-year, 24-hour design storm to match the pre- developed condition peak rate from the 10-year, 24-hour design storm. I • Limit the proposed condition peak rate from the 25-year, 24-hour design storm to match the pre- developed condition peak rate from the 25-year, 24-hour design storm. IThe proposed detention pond and proposed and future underground detention systems have been sized to meet detention requirements for compliance with SLOPES V standards using HydroCAD v10.0 software (see Appendix C). Runoff from the private portion of the north basin will be over-detained to compensate for runoff from the Hunziker basin being under-detained. The majority of the runoff from SW Wall Street will be over-detained in a I detention pond to compensate for the western section of SW Wall Street and a portion of the private drive being released undetained. Table 4 provides the pre-development peak runoff rates, the proposed conditions peak IL5The Fields Apartments :IProject1170001170521Reports\Stormwater Management Plan 117052_SWMP_final_02-26-18.docx otak I Stormwater Management Plan and the detainedpeak discharge rates under proposed conditions for the design storm events of I runoff rates g p P interest. Table 5 contains the sizing parameters for the proposed underground detention systems. Table 4: Facility Flow Control Summary Peak Flow Rate (cfs) I Basin Site Condition 2-year _ 10-year 25-year Pre-Development 0.25 0.73 1.02 North Residential Proposed 1.98 3.11 3.68 I Proposed(detained) 0.13 0.58 0.83 Pre-Development 0.03 0.08 0.11 Hunziker Proposed 0.18 0.29 0.34 I Proposed (detained) NA NA NA Pre-Development 0.27 0.81 1.13 I POC-North Proposed (detained) 0.25 0.63 0.91 Pre-Development 0.31 0.92 1.29 I South Residential Proposed 2.24 3.52 4.17 Proposed (detained) 0.32 1.30 2.36 Pre-Development 0.23 0.70 0.97 Employment* Proposed 2.17 3.23 3.75 I Proposed (detained) 0.24 0.81 1.39 Pre-Development 0.41 0.96 1.26 Wall Proposed 1.25 2.08 2.49 1 Proposed (detained) 0.17 0.38 0.54 Pre-Development 0.93 2.58 3.52 I POC-South Proposed(detained) 0.90 2.07 3.49 *The employment detention system will be included with the future employment site. I Table 5: Underground Detention System Design Parameters Detention Basin North South Residential Employment (future) Number of Chambers 58 chambers 27 chambers 36 chambers I Chamber Area 7,424 ft2 3,456 ft2 4,608 ft2 Field Height 4.6 feet 6.6 feet 5.6 feet Active Storage Volume 25,044 cubic feet 17,850 cubic feet 19,600 cubic feet I Table 6, Table 7, Table 8 and Table 9 provide the flow control structure summaries for the proposed North, South I Residential, Employment and Wall detention facilities, respectively. The Fields Apartments 6 I L:1Project1170001170521Reports\Stormwater Management PIan117052_SWMP_fnal_02-26-18.docx otak I Stormwater Management Plan ITable 6 — Flow Control Structure Summary: North IFlow Control Device Device Dimensions Orifice Diameter 1.6 inches Orifice I Orifice Invert Elevation 177.81 feet Weir Length 5.0 feet Overflow Weir Weir Crest Elevation 183.60 feet 1 Table 7 — Flow Control Structure Summary: South Residential IFlow Control Device Device Dimensions Orifice Diameter 2.3 inches Orifice I Orifice Invert Elevation 177.72 feet Weir Length 5.0 feet Overflow Weir 1 Weir Crest Elevation 185.20 feet Table 8 — Flow Control Structure Summary: Employment IFlow Control Device Device Dimensions Orifice Diameter 2.1 inches I Orifice Orifice Invert Elevation 170.00 feet Weir Length 6.0 feet Overflow Weir IWeir Crest Elevation 174.80 feet ITable 9 — Flow Control Structure Summary: Wall Flow Control Device Device Dimensions I 2-yr Orifice Orifice Diameter 1.8 inches Orifice Invert Elevation 155.00 feet I Weir Length 5.0 feet Overflow Weir Weir Crest Elevation 161.5 feet Table 10, Table 11, Table 12, and Table 13 provide the water surface elevations and detention volumes for the I four detention facilities for the design storms of interest. Table 10 — Water Surface Elevations and Detention Volumes: North ' Storm Event Water Surface Elevation (ft) Max. Volume (cf) 2-year 183.56 23,479 1 10-year 183.70 24,350 25-year 183.74 24,568 1 100-year check 183.80 24,960 The Fields Apartments 7 I L:1Project1170001170521Reports\Stormwater Management Plan 117052_SWMP_final_02-26-18.docx otak I Stormwater Management Plan 1 Table 11 Water Surface Elevations and Detention Volumes: South Residential Storm Event Water Surface Elevation (ft) Max. Volume (cf) I 2-year 185.14 16,117 10-year 185.37 16,814 I 25-year 185.47 17,119 100-year check 185.64 17642 I Table 12 —Water Surface Elevations and Detention Volumes: Employment Storm Event Water Surface Elevation (ft) Max. Volume (cf) I 2-year 174.55 17,860 10-year 174.90 19,210 1 25-year 174.97 19,471 100-year check 175.17 19,602 I Table 13 -Water Surface Elevations and Detention Volumes: Wall I Storm Event Water Surface Elevation (ft) Max. Volume (cf) 2-year 160.83 8,362 I 10-year 161.56 13,280 25-year 161.59 13,497 100-year check 161.63 13,840 1 Conveyance Inlets, manholes and pipes convey es will be used to collect and the stormwater runoff from the proposed I development, and were designed per CWS design criteria. The stormwater conveyance pipe network for the Fields Apartments property was analyzed in XP-SWMM v2014 and designed in accordance with CWS standards I for storm sewer pipe. Stormwater runoff rates for each basin, during proposed conditions, were calculated using XP-SWMM and are included in the output tables from the Runoff Mode of XP-SWMM (see Appendix D). Runoff from each of these proposed basins was routed via the proposed conveyance system. The detention volumes I and flow control structures designed in HydroCAD were input into XP-SWMM in order to model their hydraulic impacts, primarily backwater conditions on the upstream pipes. The conveyance system was sized to convey the 25-year, 24-hour storm event with a minimum of 1 foot of I freeboard between the hydraulic grade line (HGL)and the finished grade elevation. A Manning's n value of 0.013 was applied to the storm conveyance pipes in the network. Appendix D includes output information from the XP- I SWMM model, summarizing the pipe network characteristics and results of the hydraulic routing during the conveyance design storm event. Inlet Capacity Check I Inlet capacity calculations were performed for all catch basins in the proposed conveyance system using the I methodology shown in Chapter 13, Appendix D of the Oregon Department of Transportation Hydraulics Manual (ODOT, 2014), which provides guidance for inlet capacity and spacing. ODOT Method A was used, which does The Fields Apartments 8 I L:\Project\170001170521ReportsIStormwater Management PIan117052_SWMP_final_02-26-18.docx otak Stormwater Management Plan IInot apply a clogging factor to the inlet opening and limits bypass flow for inlets on grade to 30 percent. Due to narrow inlets into the LIDA planters (see Appendix G for detail), interception efficiencies for this project range I between 27 to 100 percent, with bypass flows being directed to the next downstream inlet. All bypass flows are less than 0.71 cfs, except for the inlets at the sag, where zero bypass flow was allowed and ponding depth and spread were assessed (see Appendix E). I Curb cut inlets into LIDA planters were designed for the 10-year, 5-minute storm event, while curb inlets located at sag points were designed using the 25-year, 5-minute event. A spreadsheet based on the ODOT methodology has been prepared to compute the bypass flows for each inlet in the Fields Apartments project and frontage Iimprovements, and is included in Appendix E. Operations and Maintenance IThe private stormwater facilities, comprising LIDA flow-through planters and an underground detention pipe system which includes a flow control manhole, are to be privately maintained by the property owner. An IOperations & Maintenance Plan for these stormwater facilities is in Appendix G. The plan includes an inspection and maintenance schedule, procedures, and forms to document these activities. The Owner must complete and sign the Private Stormwater Facilities Agreement (see Appendix F), and submit the form to CWS. IConclusions IThe proposed Fields Apartments project will include a stormwater management system designed to meet the requirements of SLOPES V, the City of Tigard, and Clean Water Services. The residential development and public improvements will create approximately 8.03 acres of new impervious area. Water quality and water Iquantity facilities will meet both CWS and SLOPES V standards. Water quality treatment will be achieved with LIDA planters, rain garden and vegetated filter strip. Water quantity requirements will be met by a detention pond and two underground detention systems. The onsite conveyance system has been sized to convey the 25-year, I24-hour storm event while maintaining a minimum of 1 foot of freeboard below the structure rim elevations. References ICity of Tigard, 1998. Public Improvement Design Standards, City of Tigard, July 15, 1998. I CWS, 2017. Design and Construction Standards for Sanitary Sewer and Surface Water Management, Clean Water Services, March 2017. ICWS, 2016. Low Impact Development Approaches Handbook, Clean Water Services, 2016. SCS, 1986. Technical Release 55: Urban Hydrology for Small Watersheds, United States Department of IAgriculture Soil Conservation Service, June 1986. USACE, 2014. SLOPES V for Stormwater, Transportation or Utilities, United States Army Corps of Engineers, March 14, 2014. I The Fields Apartments 9 L:1Project1170001170521Reports\Stormwater Management Plan 117052_SWMP_iinal_02-26-18.docx otak Notil'I 4.11. 0 0.0 • 11111 11111 MIN INN 11111 111111 MIN Ell NMI 11111 Ell MEI NMI 11111 4-4 - 0 a) MIN ROI MI MN 1•1111 EMI NM I= =I MIMI Ili EMI NMI NM MIN OM NM ME =I mit q� II 7411 0 fl TL V V W 1..1. MN 111111 1..1. 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Area of Interest(AOI) C/D Warning:Soil Map may not be valid at this scale. Soils D Soil Rating Polygons Enlargement of maps beyond the scale of mapping can cause I A ® Not rated or not available misunderstanding of the detail of mapping and accuracy of soil line placement.The maps do not show the small areas of contrasting L I A/D Water Features soils that could have been shown at a more detailed scale. Streams and Canals B Transportation Please rely on the bar scale on each map sheet for map 'o7p, BID i y t Rails measurements. I C Interstate Highways Source of Map: Natural Resources Conservation Service Web Soil Survey URL: http://websoilsurvey.nres.usda.gov C/D US Routes Coordinate System: Web Mercator(EPSG:3857) D Major Roads Maps from the Web Soil Survey are based on the Web Mercator n Not rated or not availableLocal Roads projection,which preserves direction and shape but distorts distance and area.A projection that preserves area,such as the Soil Rating Lines Background Albers equal-area conic projection,should be used if more accurate AK," AAerial Photography calculations of distance or area are required. 0, A/D This product is generated from the USDA-N RCS certified data as of B the version date(s)listed below. A„r B/D Soil Survey Area: Washington County,Oregon Survey Area Data: Version 14,Sep 16,2016 • C Soil map units are labeled(as space allows)for map scales 1:50,000 C/D or larger. D Date(s)aerial images were photographed: Aug 3,2014—Aug 23, • * Not rated or not available 2014 Soil Rating Points The orthophoto or other base map on which the soil lines were A compiled and digitized probably differs from the background imagery displayed on these maps.As a result,some minor shifting • A/D of map unit boundaries may be evident. ▪ B ® B/D USDA Natural Resources Web Soil Survey 12/14/2016 di" Conservation Service National Cooperative Soil Survey Page 2 of 4 i 111111 - EN I i - - - i N - - - EN 11111 N MI r IHydrologic Soil Group—Washington County,Oregon Fields Property I i Hydrologic Soil Group I Hydrologic Soil Group—Summary by Map Unit—Washington County,Oregon(OR067) Map unit symbol Map unit name Rating Acres in AO1 Percent of AOI Aloha oam 3. 11B Corneliulsland Kinton silt C/D 4.7 19.8% loans,2 to 7 percent slopes I11C Cornelius and Kinton silt C 8.3 34.8% barns,7 to 12 percent slopes I 37C Quatama loam,7 to 12 C 7.3 30.4% percent slopes Totals for Area of Interest 23.9 100.0% I I I I I I III I I I USDA Natural Resources Web Soil Survey 12/14/2016 mos Conservation Service National Cooperative Soil Survey Page 3 of 4 I Hydrologic Soil Group—Washington County,Oregon Fields Property 1 Description Hydrologic soil groups are based on estimates of runoff potential. Soils are assigned to one of four groups according to the rate of water infiltration when the soils are not protected by vegetation, are thoroughly wet, and receive precipitation from long-duration storms. The soils in the United States are assigned to four groups (A, B, C, and D)and ' three dual classes (ND, B/D, and C/D). The groups are defined as follows: Group A. Soils having a high infiltration rate(low runoff potential)when thoroughly wet. These consist mainly of deep, well drained to excessively drained sands or gravelly sands. These soils have a high rate of water transmission. Group B. Soils having a moderate infiltration rate when thoroughly wet. These , consist chiefly of moderately deep or deep, moderately well drained or well drained soils that have moderately fine texture to moderately coarse texture. These soils have a moderate rate of water transmission. Group C. Soils having a slow infiltration rate when thoroughly wet. These consist chiefly of soils having a layer that impedes the downward movement of water or soils of moderately fine texture or fine texture.These soils have a slow rate of water transmission. Group D. Soils having a very slow infiltration rate (high runoff potential)when 1 thoroughly wet. These consist chiefly of clays that have a high shrink-swell potential, soils that have a high water table, soils that have a claypan or clay layer at or near the surface, and soils that are shallow over nearly impervious material. These soils have a very slow rate of water transmission. If a soil is assigned to a dual hydrologic group (ND, B/D, or C/D), the first letter is for drained areas and the second is for undrained areas. Only the soils that in their natural condition are in group D are assigned to dual classes. Rating Options Aggregation Method: Dominant Condition Component Percent Cutoff- None Specified Tie-break Rule: Higher 1 I USDA Natural Resources Web Soil Survey 12/14/2016 -dim Conservation Service National Cooperative Soil Survey Page 4 of 4 I Chapter 2 Estimating Runoff Technical Release 55 IUrban Hydrology for Small Watersheds I Existing Conditions Table 2-2c Runoff curve numbers for other agricultural lands_v nii ICurve numbers for ----------------------- Cover description ------------------------- hydrologic soil group------- ' Hydrologic Cover type condition A B C D Pasture,grassland,or range—continuous Poor 68 79 86 89 I forage for grazing.2/ Fair 49 69 79 84 Good 39 61 74 80 Meadow—continuous grass,protected from — 30 58 71 78 grazing and generally mowed for hay. Brush—brush-weed-grass mixture with brush Poor 48 67 77 83 the major element.5' Fair 35 56 70 77 I Good 30 v 48 65 73 Woods—grass combination(orchard Poor 57 73 82 86 or tree farm).5' Fair 43 65 76 82 I Good 32 58 72 79 Woods. Poor 45 66 77 83 Fair 36 60 73 4— 79 *--- I Good 30_v 55 70 77 Farmsteads—buildings,lanes,driveways, 59 74 82 86 and surrounding lots. I 1 Average runoff condition,and Ia=0.2S. 2 Poor: <50%)ground cover or heavily grazed with no mulch. Fair: 50 to 75%ground cover and not heavily grazed. Good: >75%ground cover and lightly or only occasionally grazed. I 3 Poor. <50%ground cover. Fair: 50 to 75%ground cover. Good: >75%ground cover. 4 Actual curve number is less than 30;use CN=30 for runoff computations. Ia CN's shown were computed for areas with 50%woods and 50%grass(pasture)cover.Other combinations of conditions may be computed from the CN's for woods and pasture. 6 Poor: Forest litter,small trees,and brush are destroyed by heavy grazing or regular burning. Fair: Woods are grazed but not burned,and some forest litter covers the soil. IGood: Woods are protected from grazing,and litter and brush adequately cover the soil. I I I 1 (210-VI-TR-55,Second Ed.,June 1986) 2-7 I Chapter 2 Estimating Runoff Technical Release 55 I Urban Hydrology for Small Watersheds Proposed Conditions I Table 2-7a Runoff curve numbers for urban areas v iiiimilm I Curve numbers for -------------------------- Cover description — —---- -----hydrologic soil group — Average percent I Cover type and hydrologic condition impervious area_v A B C D Fully developed urban areas(vegetation established) I Open space(lawns,parks,golf courses,cemeteries,etc.)3/: Poor condition(grass cover<50%) 68 79 86 89 Fair condition(grass cover 50%to 75%) 49 69 79 84- f-- I Good condition(grass cover>75%) 39 61 74 * 80 Impervious areas: Paved parking lots,roofs,driveways,etc. (excluding right-of-way) 98 98 4— 98 98 I Streets and roads: Paved;curbs and storm sewers(excluding right-of-way) 98 98 98 98 Paved;open ditches(including right-of-way) 83 89 92 93 I Gravel(including right-of-way) 76 85 89 91 Dirt(including right-of-way) 72 82 87 89 Western desert urban areas: Natural desert landscaping(pervious areas only)_v 63 77 85 88 I Artificial desert landscaping(impervious weed barrier, desert shrub with 1-to 2-inch sand or gravel mulch and basin borders) 96 96 96 96 Urban districts: I Commercial and business 85 89 92 94 95 Industrial 72 81 88 91 93 Residential districts by average lot size: 1/8 acre or less(town houses) 65 77 85 90 92 I 1/4 acre 38 61 75 83 87 1/3 acre 30 57 72 81 86 1/2 acre 25 54 70 80 85 1 acre 20 51 68 79 84 1 2 acres 12 46 65 77 82 Developing Urban ar@8S _:, Newly graded areas (pervious areas only,no vegetation)5i 77 86 91 94 I Idle lands(CN's are determined using cover types similar to those in table 2-2c). 1 Average runoff condition,and Ia=0.2S. 2 The average percent impervious area shown was used to develop the composite CN's.Other assumptions are as follows:impervious areas are I directly connected to the drainage system,impervious areas have a CN of 98,and pervious areas are considered equivalent to open space in good hydrologic condition.CN's for other combinations of conditions may be computed using figure 2-3 or 2-4. 3 CN's shown are equivalent to those of pasture.Composite CN's may be computed for other combinations of open space cover type. I 4 Composite CN's for natural desert landscaping should be computed using figures 2-3 or 2-4 based on the impervious area percentage (CN=98)and the pervious area CN.The pervious area CN's are assumed equivalent to desert shrub in poor hydrologic condition. 5 Composite CN's to use for the design of temporary measures during grading and construction should be computed using figure 2-3 or 2-4 based on the degree of development(impervious area percentage)and the CN's for the newly graded pervious areas. I (210-VI-TR-55,Second Ed.,June 1986) 2-5 I MI NM MN N En I NM EN MN 11111 MI NM N MI E M all UN MB Basin Areas 17052 - The Fields Apartments Pre-developed Drainage Basins: Impervious Area Pervious Area Total Area Sidewalk Roadway Basin Name (sf) (sf) Roof (sf) Total (sf) Total (ac) Total (sf) Total (ac) Total (sf) Total (ac) Hunziker 0 0 0 0 0.000 22,423 0.51 22,423 0.51 North Residential 0 0 0 0 0.00 246,275 5.65 246,275 5.65 South Residential 0 0 0 0 0.00 300,068 6.89 300,068 6.89 Employment 0 0 0 0 0.00 226,527 5.20 226,527 5.20 Wall 0 0 0 0 0.00 207,846 4.77 207,846 4.77 Total Onsite Managed 23.03 West Slope (drains offsite) 0 0 0 0 0.00 53,698 1.23 53,698 1.23 East Wall (drains offsite) 0 0 0 0 0.00 1,633 0.04 1,633 0.04 Existing Drainage Basin: Varns (offsite) Future Connection estimated 60% impervious 242,565 5.57 161,710 3.71 404,275 9.28 Basin Areas 17052- The Fields Apartments Proposed (Post-developed) Drainage Basins: Impervious Area Pervious Area Total Area Basin Name Sidewalk (sf) Roadway (sf) Roof(sf) Total (sf) Total (ac) Total (sf) Total (ac) Total (sf) Total (ac) North -Total 22,494 71,634 30,091 124,219 2.85 144,479 3.32 268,698 6.17 North- Residential 18,197 65,093 30,091 113,381 2.60 132,894 3.05 246,275 5.65 Hunkizer 4,297 6,541 0 10,838 0.249 11,585 0.266 22,423 0.51 H1 1,877 3,402 0 5,279 0.12 5,973 0.14 11,252 0.26 H2 2,420 3,139 0 5,559 0.13 5,612 0.13 11,171 0.26 M1 0 0 11,998 11,998 0.28 956 0.02 12,954 0.30 M2 51 0 11,650 11,701 0.27 971 0.02 12,672 0.29 M3 2161 0 4,183 6,344 0.15 12,990 0.30 19,334 0.44 R1 1,124 11,080 0 12,204 0.28 3,263 0.07 15,467 0.36 R2 565 7,961 0 8,526 0.20 2,857 0.07 11,383 0.26 R3 1,292 11,128 0 12,420 0.29 23,436 0.54 35,856 0.82 R4 1,929 9,886 0 11,815 0.27 13,622 0.31 25,437 0.58 R5 2,849 6,000 2,260 11,109 0.26 16,810 0.39 27,919 0.64 R6 2,176 2,661 0 4,837 0.11 7,830 0.18 12,667 0.29 R7 1,688 4,370 0 6,058 0.14 5,904 0.14 11,962 0.27 R8 2,843 12,007 0 14,850 0.34 41,135 0.94 55,985 1.29 R8a 1,519 0 0 1,519 0.03 3,120 0.07 4,639 0.11 South -Total 53,097 252,172 77,470 382,739 8.79 351,702 8.07 734,441 16.86 South-Residential 22,735 89,551 45,590 157,876 3.62 142,192 3.26 300,068 6.89 Wall 14,040 56,411 0 70,451 1.62 137,395 3.15 207,846 4.77 Employment 16,322 106,210 31,880 154,412 3.54 72,115 1.66 226,527 5.20 W1 2733 8554 0 11,287 0.26 30,765 0.71 42,052 0.97 W2a 843 4770 0 5,613 0.13 11,807 0.27 17,420 0.40 W2b 1125 6350 0 7,475 0.17 12,942 0.30 20,417 0.47 W3a 1084 5682 0 6,766 0.16 5,988 0.14 12,754 0.29 W3b 454 2671 0 3,125 0.07 849 0.02 3,974 0.09 W4 1054 6312 0 7,366 0.17 1,999 0.05 9,365 0.21 W5 458 3136 0 3,594 0.08 4,292 0.10 7,886 0.18 M4 0 0 11,038 11,038 0.25 875 0.02 11,913 0.27 M5 446 0 14,210 14,656 0.34 8,567 0.20 23,223 0.53 M5a 2810 0 0 2,810 0.06 11,585 0.27 14,395 0.33 M6 0 0 13,752 13,752 0.32 1,201 0.03 14,953 0.34 R9 934 7535 0 8,469 0.19 1,440 0.03 9,909 0.23 Page 1 of 3 Ell - M M M IIIIII M NM MI O MN IIIIII I IIIIII INIIII MO M PIN IIIIII MS MB MB NM MN 11111 11111 M 111111 N M NU 111111 NE EN MI all MN NE Basin Areas 17052- The Fields Apartments Proposed (Post-developed) Drainage Basins: Impervious Area Pervious Area Total Area Basin Name Sidewalk (sf) Roadway (sf) Roof (sf) Total (sf) Total (ac) Total (sf) Total (ac) Total (sf) Total (ac) R10 2474 13017 1 15,492 0.36 4,443 0.10 19,935 0.46 R11 953 8362 0 9,315 0.21 3,570 0.08 12,885 0.30 R12 814 9771 0 10,585 0.24 1,913 0.04 12,498 0.29 R13 3065 4171 3,605 10,841 0.25 19,885 0.46 30,726 0.71 R14 1601 0 2,984 4,585 0.11 10,289 0.24 14,874 0.34 R15 2330 9293 0 11,623 0.27 15,419 0.35 27,042 0.62 R16 1917 10611 0 12,528 0.29 22,102 0.51 34,630 0.79 R17 1863 10015 0 11,878 0.27 20,894 0.48 32,772 0.75 R18 574 2999 0 3,573 0.08 11,051 0.25 14,624 0.34 R19 190 1879 0 2,069 0.05 2,203 0.05 4,272 0.10 R20 621 1241 0 1,862 0.04 954 0.02 2,816 0.06 R21 784 2520 0 3,304 0.08 2,234 0.05 5,538 0.13 R22 638 1886 0 2,524 0.06 2,469 0.06 4,993 0.11 R23 721 6251 0 6,972 0.16 1,098 0.03 8,070 0.19 W7 422 1172 0 1,594 0.04 2,194 0.05 3,788 0.09 W8 881 5341 0 6,222 0.14 7,336 0.17 13,558 0.31 W9 125 4390 0 4,515 0.10 2,463 0.06 6,978 0.16 W10 2651 0 0 2,651 0.06 18,080 0.42 20,731 0.48 W6 2210 8033 0 10,243 0.24 38,680 0.89 48,923 1.12 C2 493 2467 0 2,960 0.07 5,434 0.12 8,394 0.19 C3 2756 10228 0 12,984 0.30 24,153 0.55 37,137 0.85 C4 2706 13528 0 16,234 0.37 1,888 0.04 18,122 0.42 C5 99 1219 0 1,318 0.03 1,349 0.03 2,667 0.06 C6 1021 6673 0 7,694 0.18 8,756 0.20 16,450 0.38 C7 145 2286 0 2,431 0.06 3,282 0.08 5,713 0.13 C8 251 2613 0 2,864 0.07 4,358 0.10 7,222 0.17 C9 993 8999 0 9,992 0.23 2,960 0.07 12,952 0.30 010 0 2988 0 2,988 0.07 1,674 0.04 4,662 0.11 C11 459 8513 0 8,972 0.21 4,273 0.10 13,245 0.30 C12 0 2685 0 2,685 0.06 775 0.02 3,460 0.08 C13 528 0 11,375 11,903 0.27 447 0.01 12,350 0.28 C14 512 3638 0 4,150 0.10 707 0.02 4,857 0.11 C15 0 0 11,127 11,127 0.26 775 0.02 11,902 0.27 Page 2 of 3 Basin Areas 17052- The Fields Apartments Proposed (Post-developed) Drainage Basins: Impervious Area Pervious Area Total Area Basin Name Sidewalk (sf) Roadway(sf) Roof (sf) Total (sf) Total (ac) Total (sf) Total (ac) Total (sf) Total (ac) C16 841 3865 0 4,706 0.11 1,246 0.03 5,952 0.14 C17 0 0 9,378 9,378 0.22 734 0.02 10,112 0.23 C18 1089 6629 0 7,718 0.18 2,381 0.05 10,099 0.23 C19 2008 12825 0 14,833 0.34 2,973 0.07 17,806 0.41 C20 603 5556 0 6,159 0.14 1,317 0.03 7,476 0.17 C21 1818 11498 0 13,316 0.31 2,633 0.06 15,949 0.37 Total Managed 75,591 323,806 107,561 506,958 11.64 496,182 11.39 1,003,139 23.03 West Slope 436 0 0 436 0.01 56,053 1.29 56,489 1.30 East Wall 0 0 0 0 0.00 1,633 0.04 1,633 0.04 South Res Detained 22,014 83,300 45,590 150,904 3.46 141,094 3.24 291,998 6.70 Employment Detained 16,322 106,210 31,880 154,412 3.54 72,115 1.66 226,527 5.20 Wall Detained 12,154 42,372 0 54,526 1.25 121,110 2.78 175,636 4.03 Wall Undetained 1,886 14,039 0 15,925 0.37 16,285 0.37 32,210 0.74 South Res Undetained 721 6,251 0 6,972 0.16 1,098 0.03 8,070 0.19 Page 3 of 3 I 1 Time of Concentration Calculations I I Project Name: Fields Property By: RCH Date: 09/14/17 Project Number: 17052 Check: Date: IPre-dev North Pre-dev South Pre-dev South BASINS Residential Residential Commercial SHEET FLOW I INPUT Surface Description (from Table 3-I) Woods Woods Woods IManning's Roughness Coefficient 0.4 0.4 0.4 Flow Length , L (<300 ft) ft 300 300 300 2-Year, 24-Hour Rainfall, P2 in 2.5 2.5 2.5 Land Slope, s ft/ft 0.084 0.108 0.110 OUTPUT ITravel Time hr 0.55 0.50 0.49 SHALLOW CONCENTRATED FLOW I INPUT Surface Description Woods Woods Woods K value 5 5 5 IFlow Length, L ft 220 250 255 Watercourse Slope, s ft/ft 0.115 0.104 0.090 IOUTPUT Average Velocity, V ft/s 1.69 1.61 1.50 Travel Time hr 0.04 0.04 0.05 ICHANNEL FLOW INPUT ICross Sectional Flow Area, a ft2 - Wetted Perimeter, pW ft - I Channel Slope, s ft/ft - Manning's Roughness Coefficient - Flow Length, L ft - IOUTPUT Average Velocity, V ft/s - I Hydraulic Radius, r = a/pw ft - Travel Time hr 0.00 0.00 0.00 Basin Time of Concentration, Tc hrs 0.59 0.54 0.54 Imin 35.1 32.3 32.4 I I Time of Concentration Calculations I Project Name: Fields Property By: RCH Date: 07/18/17 I Project Number: 17052 Check: Date: Pre-dev I BASINS Existing Varns Hunziker Pre-dev Wall SHEET FLOW I INPUT Surface Description (from Table 3-I) Grass Woods Woods I Manning's Roughness Coefficient 0.15 0.4 0.4 Flow Length , L (<300 ft) ft 300 210 300 2-Year, 24-Hour Rainfall, P2 in 2.5 2.5 2.5 I Land Slope, s ft/ft 0.022 0.119 0.088 OUTPUT Travel Time hr 0.43 0.36 0.54 SHALLOW CONCENTRATED FLOW INPUT I Surface Description (paved or unpaved) Paved Woods K Value 27 5 I Flow Length, L ft 386 60 Watercourse Slope, s ft/ft 0.047 0.042 OUTPUT I Average Velocity, V ft/s 5.83 1.02 Travel Time hr 0.02 0.02 I CHANNEL FLOW INPUT - Cross Sectional Flow Area, a ft2 - I Wetted Perimeter, pW ft - Channel Slope, s ft/ft - I Manning's Roughness Coefficient - Flow Length, L ft - I OUTPUT Average Velocity, V ft/s - Hydraulic Radius, r = a/pw ft - I Travel Time hr 0.00 0.00 0.00 Basin Time of Concentration, Tc hrs 0.45 0.36 0.55 I min 27.0 21.5 33.3 I - o 0 a - L V a) 4-+ cU X a) a M N — — N M M — M M N I — — M M NM N N M M E E M IIM M IIIIII M M MO 111111 M M IIIIII M M M M Water Quality Sizing 17052- The Fields Apartments WQV= (0.36 inch)(12 inch)(Proposed IA,ft2) (CWS,4.05.06) WQV= (1.25 inch)(12 inch)(Proposed Impervious Area,ft2) SLOPES V Contributing Contributing Contributing Req Treatment Min.Depth of Impervious Area Impervious Pervious Area LIDA @ Area Water Quality Actual Sizing LIDA Facility (sf) Area(ac) (ac) WQV(cf) .06 Shown(sf) Mix(in) Factor Total 689,788 15.84 15.27 41,387 46,178 Total Public and Residential 354,926 8.15 9.19 21,296 23,035 6.49% Public 61,095 1.40 1.71 3,666 3,409 5.58% Varns 10,590 0.24 1103 635 495 24 4.7% H1 5,279 0.121 0.137 550 317 250 24 4,7% W1 11,287 0.259 0.706 1,176 677 690 18 6.1% W2a 5,613 0.129 0.271 585 337 383 18 6.8% W2b 7,475 0.172 0.297 779 449 469 18 6.3% W3a 6,766 0.155 0.137 705 406 420 18 6.2% W3b 3,125 0.072 0.019 326 188 196 18 6.3% W4 7,366 0.169 0.046 767 442 346 24 4.7% W5 3,594 0.083 0.099 374 216 160 24 4.5% North Residential 113,381 2.60 3.05 6,803 7,987 7.04% M1 11,998 0.275 0.022 1,250 720 725 18 6.0% M2 11,701 0.269 0.022 1,219 702 741 18 6.3% M3 6,344 0.146 0.298 661 381 404 18 6.4% R1 12,204 0.280 0.075 1,271 732 779 18 6.4% R2 8,526 0.196 0.066 888 512 648 18 7.6% R3 12,420 0.285 0.538 1,294 745 785 18 6.3% R4 11,815 0.271 0.313 1,231 709 736 18 6.2% R5 * 15,946 0.366 0.566 1,661 957 993 18 6.2% R7 6,058 0.139 0.136 631 363 273 24 4.5% R8 14,850 0.341 0.944 1,547 891 784 24 5.3% R8a 1,519 0.035 0.072 158 91 1,119 18 73.7% vegetated filter strip * Facility serves two basins. L:\Project\17000\17052\WaterRes\17052 BasinAreas.xlsx 1 of 3 0 V Water Quality Sizing 17052- The Fields Apartments WQV= (0.36 inch)\12inch)(Proposed IA,ft2) (CWS,4.05.06) WQV= (1.25 inch)(12 ttch)(Proposed Impervious Area,ft2) SLOPES V Contributing Contributing Contributing Req Treatment Min.Depth of Impervious Area Impervious Pervious Area LIDA @ Area Water Quality Actual Sizing LIDA Facility (sf) Area(ac) (ac) WQV(cf) .06 Shown(sf) Mix(in) Factor South Residential 180,450 4.14 4.43 10,827 11,639 6.45% M4 11,038 0.253 0.020 1,150 662 813 18 7.4% M5 14,656 0.336 0.197 1,527 879 1,059 18 7.2% M5a 2,810 0.065 0.266 293 169 180 18 6.4% M6 13,752 0.316 0.028 1,433 825 993 18 7.2% R9 8,469 0.194 0.033 882 508 524 18 6.2% R10 15,492 0.356 0.102 1,614 930 967 18 6.2% R11 9,315 0.214 0.082 970 559 569 18 6.1% R12 10,585 0.243 0.044 1,103 635 679 18 6.4% R13 10,841 0.249 0.456 1,129 650 640 18 5.9% R14 4,585 0.105 0.236 478 275 347 18 76% R15 11,623 0.267 0.354 1,211 697 697 18 6.0% R16 12,528 0.288 0.507 1,305 752 785 18 6.3% R17 11,878 0.273 0.480 1,237 713 736 18 6.2% R18 3,573 0.082 0.254 372 214 228 18 6.4% R19 2,069 0.047 0.051 216 124 128 18 6.2% R20 1,862 0.043 0.022 194 112 115 18 6.2% R21 3,304 0.076 0.051 344 198 200 18 6.1% R22 2,524 0.058 0.057 263 151 159 18 6.3% W8 * 7,816 0.179 0.219 814 469 501 18 6.4% W9 * 11,487 0.264 0.082 1,197 689 702 18 6.1% W6 10,243 0.235 0.888 1,067 615 617 18 6.0% * Facility serves two basins. L:\Project\17000\17052\WaterRes\17052_BasinAreas.xlsx 2 of 3 - Mill - IIIII NMI NM IIIII - Ell OM NM IIIIII 111111 IIIIII MN Mill MI - - EN — — EN MI — I MN MN MI MI EN M 1 E 1 ! EN Water Quality Sizing 17052-The Fields Apartments WQV= (0.36 inch)(12 inch))(Proposed IA,f tz) (CWS,4.05.06) WQV= (1.25 inch)(12 i th))(Proposed Impervious Area,ftz) SLOPES V Contributing Contributing Contributing Req Treatment Min.Depth of Impervious Area Impervious Pervious Area LIDA @ Area Water Quality Actual Sizing LIDA Facility (sf) Area(ac) (ac) WQV(cf) .06 Shown(sf) Mix(in) Factor Future Employment Site C2 2,960 0.068 0.125 308 178 202 18 6.8% C3 12,984 0.298 0.554 1,352 779 765 24 5.9% C4 16,234 0.373 0.043 1,691 974 1,029 18 6.3% C5 1,318 0.030 0.031 137 79 440 18 33.4% C6 7,694 0.177 0.201 801 462 480 18 6.2% C7 2,431 0.056 0.075 253 146 113 24 4.6% C8 2,864 0.066 0.100 298 172 191 18 6.7% C9 9,992 0.229 0.068 1,041 600 1,202 18 12.0% C10 2,988 0.069 0.038 311 179 387 18 13.0% C11 8,972 0.206 0.098 935 538 1,202 18 13.4% C12 2,685 0.062 0.018 280 161 180 18 6.7% C13 11,903 0.273 0.010 1,240 714 865 18 7.3% C14 4,150 0.095 0.016 432 249 222 24 5.3% C15 11,127 0.255 0.018 1,159 668 696 18 6.3% C16 4,706 0.108 0.029 490 282 397 18 8.4% C17 9,378 0.215 0.017 977 563 576 18 6.1% C18 7,718 0.177 0.055 804 463 486 18 6.3% C19 14,833 0.341 0.068 1,545 890 900 18 6.1% C20 6,159 0.141 0.030 642 370 390 18 6.3% C21 13,316 0.306 0.060 1,387 799 780 24 5.9% #"'lo Sizing factor less than 6%and water quality media depth increased to 24" #% Sizing factor 10%greater than required L:\Project\17000\17052\WaterRes\17052_BasinAreas.xlsx 3 of 3 ig A 0 U 0 L U a_ MI Ell MI MI MI MI — MIN MI MI MIN MO IMO MIN NM =I HIM OM MINI 1 I 1 <8S> <9S> Pre-dev - N th Pre-d v Hunziker Post-d v North Post-dev Hunziker Residential Resi ential 10P 11 P I> 12P i POC - Pre-North Detention North POC - Post-North Residential 2yr=0.27cfs; 2yr=0.25cfs; 10yr=0.81 cfs; 10yr=0.63cfs; 25yr=1.13cfs 25yr=0.91 cfs I /Subca Reach 'on. Link Routing Diagram for 17052_FinalDesign J Prepared by Otak, Inc., Printed 2/22/2018 HydroCAD®10.00-14 s/n 05775 ©2015 HydroCAD Software Solutions LLC I North 1 7052_Final Design Type IA 24-hr 2yr Rainfall=2.50" Prepared by Otak, Inc. Printed 2/22/2018 HydroCAD® 10.00-14 s/n 05775 ©2015 HydroCAD Software Solutions LLC Page 2 Summary for Subcatchment 1S: Pre-dev - North Residential Runoff = 0.25 cfs @ 8.90 hrs, Volume= 0.267 af, Depth= 0.57" ' Runoff by SBUH method, Split Pervious/Imperv., Time Span= 0.00-72.00 hrs, dt= 0.06 hrs Type IA 24-hr 2yr Rainfall=2.50" Area (ac) CN Description 5.650 73 Woods, Fair, HSG C 1 5.650 73 100.00% Pervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 35.1 Direct Entry, Summary for Subcatchment 2S: Pre-dev Hunziker 1 Runoff = 0.03 cfs @ 8.28 hrs, Volume= 0.024 af, Depth= 0.57" Runoff by SBUH method, Split Pervious/Imperv., Time Span= 0.00-72.00 hrs, dt= 0.06 hrs Type IA 24-hr 2yr Rainfall=2.50" Area (ac) CN Description 0.510 73 Woods, Fair, HSG C 0.510 73 100.00% Pervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 21.5 Direct Entry, Summary for Subcatchment 8S: Post-dev North Residential I Runoff = 1.98 cfs @ 7.95 hrs, Volume= 0.705 af, Depth= 1.50" Runoff by SBUH method, Split Pervious/lmperv., Time Span= 0.00-72.00 hrs, dt= 0.06 hrs 1 Type IA 24-hr 2yr Rainfall=2.50" Area (ac) CN Description , 2.600 98 Paved parking, HSG C 3.050 79 50-75% Grass cover, Fair, HSG C 5.650 88 Weighted Average 3.050 79 53.98% Pervious Area 2.600 98 46.02% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 5.0 Direct Entry, I I I I 17052 FinalDesign North Type IA 24-hr 2yr Rainfall=2.50" Prepared by Otak, Inc. Printed 2/22/2018 I HydroCAD® 10.00-14 s/n 05775 ©2015 HydroCAD Software Solutions LLC Page 3 Summary for Subcatchment 9S: Post-dev Hunziker IRunoff = 0.18 cfs @ 7.95 hrs, Volume= 0.065 af, Depth= 1.54" Runoff by SBUH method, Split Pervious/lmperv., Time Span= 0.00-72.00 hrs, dt= 0.06 hrs I Type IA 24-hr 2yr Rainfall=2.50" Area (ac) CN Description I 0.250 98 Paved parking, HSG C 0.260 79 50-75% Grass cover, Fair, HSG C 0.510 88 Weighted Average I 0.260 79 50.98% Pervious Area 0.250 98 49.02% Impervious Area ITc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 5.0 Direct Entry, ISummary for Pond 10P: POC - Pre-North Inflow Area = 6.160 ac, 0.00% Impervious, Inflow Depth = 0.57" for 2yr event I Inflow = 0.27 cfs @ 8.87 hrs, Volume= 0.291 af Primary 0.27 cfs @ 8.87 hrs, Volume= 0.291 af, Atten= 0%, Lag= 0.0 min IRouting by Dyn-Stor-Ind method, Time Span= 0.00-72.00 hrs, dt= 0.06 hrs/3 Summary for Pond 11P: Detention North Residential IInflow Area = 5.650 ac, 46.02% Impervious, Inflow Depth = 1.50" for 2yr event Inflow = 1.98 cfs @ 7.95 hrs, Volume= 0.705 af Outflow = 0.13 cfs @ 24.08 hrs, Volume= 0.553 af, Atten= 93%, Lag= 967.9 min I Primary 0.13 cfs @ 24.08 hrs, Volume= 0.553 af Routing by Dyn-Stor-Ind method, Time Span= 0.00-72.00 hrs, dt= 0.06 hrs/ 3 1 Peak Elev= 183.56' @ 24.08 hrs Surf.Area= 0.170 ac Storage= 0.539 af Plug-Flow detention time= 1,603.0 min calculated for 0.553 af (78% of inflow) ICenter-of-Mass det. time= 1,465.4 min ( 2,195.7 - 730.3 ) Volume Invert Avail.Storage Storage Description #1 A 179.81' 0.000 af 16.00'W x 464.001 x 4.58'H Field A I 0.781 af Overall - 0.781 af Embedded = 0.000 af x 30.0% Voids #2A 179.81' 0.575 of Oldcastle_Storm_Capture SC1 4 x 58 Inside #1 Inside= 84.0"W x 48.0"H => 27.38 sf x 16.00'L = 438.0 cf I Outside= 96.0"W x 55.0"H => 36.67 sf x 16.00'L = 586.7 cf 2 Rows adjusted for 360.0 cf perimeter wall 0.575 af Total Available Storage IStorage Group A created with Chamber Wizard 1 North 17052_FinalDesign Type IA 24-hr 2yr Rainfall=2.50" Prepared by Otak, Inc. Printed 2/22/2018 HydroCAD® 10.00-14 s/n 05775 ©2015 HydroCAD Software Solutions LLC Page 4 Device Routing Invert Outlet Devices #1 Primary 179.81' 12.0" Round RCP Round 12" L= 50.0' RCP, sq.cut end projecting, Ke= 0.500 Inlet/Outlet Invert= 179.81' / 179.31' S= 0.0100 7' Cc= 0.900 n= 0.013 Concrete pipe, bends & connections, Flow Area= 0.79 sf #2 Device 1 179.81' 1.6"Vert. Orifice/Grate C= 0.600 #3 Device 1 183.60' 5.0' long x 0.5' breadth Broad-Crested Rectangular Weir Head (feet) 0.20 0.40 0.60 0.80 1.00 Coef. (English) 2.80 2.92 3.08 3.30 3.32 Primary OutFlow Max=0.13 cfs @ 24.08 hrs HW=183.56' TW=0.00' (Dynamic Tailwater) t-1=RCP_Round 12" (Passes 0.13 cfs of 6.49 cfs potential flow) 4L2=Orifice/Grate (Orifice Controls 0.13 cfs @ 9.24 fps) 3=Broad-Crested Rectangular Weir ( Controls 0.00 cfs) Summary for Pond 12P: POC - Post-North Inflow Area = 6.160 ac, 46.27% Impervious, Inflow Depth > 1.21" for 2yr event 1 Inflow = 0.25 cfs @ 7.96 hrs, Volume= 0.619 af Primary = 0.25 cfs @ 7.96 hrs, Volume= 0.619 af, Atten= 0%, Lag= 0.0 min Routing by Dyn-Stor-Ind method, Time Span= 0.00-72.00 hrs, dt= 0.06 hrs/ 3 1 I 1 1 I I 1 I — North 17052 FinalDesign Type IA 24-hr 10yr Rainfall=3.45" Prepared by Otak, Inc. Printed 2/22/2018 ' HydroCAD® 10.00-14 s/n 05775 ©2015 HydroCAD Software Solutions LLC Page 5 Summary for Subcatchment 1S: Pre-dev - North Residential Runoff = 0.73 cfs @ 8.24 hrs, Volume= 0.540 af, Depth= 1.15" Runoff by SBUH method, Split Pervious/lmperv., Time Span= 0.00-72.00 hrs, dt= 0.06 hrs Type IA 24-hr 10yr Rainfall=3.45" Area (ac) CN Description 5.650 73 Woods, Fair, HSG C 5.650 73 100.00% Pervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 35.1 Direct Entry, ' Summary for Subcatchment 2S: Pre-dev Hunziker ' Runoff = 0.08 cfs @ 8.10 hrs, Volume= 0.049 af, Depth= 1.15" Runoff by SBUH method, Split Pervious/lmperv., Time Span= 0.00-72.00 hrs, dt= 0.06 hrs Type IA 24-hr 10yr Rainfall=3.45" Area (ac) CN Description 0.510 73 Woods, Fair, HSG C 1 0.510 73 100.00% Pervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 21.5 Direct Entry, ' Summary for Subcatchment 8S: Post-dev North Residential Runoff = 3.11 cfs @ 7.94 hrs, Volume= 1.085 af, Depth= 2.30" Runoff by SBUH method, Split Pervious/Imperv., Time Span= 0.00-72.00 hrs, dt= 0.06 hrs Type IA 24-hr 10yr Rainfall=3.45" ' Area (ac) CN Description 2.600 98 Paved parking, HSG C 3.050 79 50-75% Grass cover, Fair, HSG C ' 5.650 88 Weighted Average 3.050 79 53.98% Pervious Area 2.600 98 46.02% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 5.0 Direct Entry, I North 17052_FinalDesign Type IA 24-hr 10yr Rainfall=3.45" Prepared by Otak, Inc. Printed 2/22/2018 HydroCAD® 10.00-14 s/n 05775 ©2015 HydroCAD Software Solutions LLC Pace 6 I Summary for Subcatchment 9S: Post-dev Hunziker Runoff = 0.29 cfs @ 7.94 hrs, Volume= 0.100 af, Depth= 2.36" Runoff by SBUH method, Split Pervious/Imperv., Time Span= 0.00-72.00 hrs, dt= 0.06 hrs Type IA 24-hr 10yr Rainfall=3.45" Area (ac) CN Description I 0.250 98 Paved parking, HSG C 0.260 79 50-75% Grass cover, Fair, HSG C 0.510 88 Weighted Average 0.260 79 50.98% Pervious Area 0.250 98 49.02% Impervious Area Tc Length Slope Velocity Capacity Description I(min) (feet) (ft/ft) (ft/sec) (cfs) 5.0 Direct Entry, Summary for Pond 10P: POC - Pre-North 1 Inflow Area = 6.160 ac, 0.00% Impervious, Inflow Depth = 1.15" for 10yr event Inflow = 0.81 cfs @ 8.22 hrs, Volume= 0.588 af Primary = 0.81 cfs @ 8.22 hrs, Volume= 0.588 af, Atten= 0%, Lag= 0.0 min Routing by Dyn-Stor-Ind method, Time Span= 0.00-72.00 hrs, dt= 0.06 hrs/3 I Summary for Pond 11P: Detention North Residential Inflow Area = 5.650 ac, 46.02% Impervious, Inflow Depth = 2.30" for 10yr event I Inflow = 3.11 cfs @ 7.94 hrs, Volume= 1.085 of Outflow = 0.58 cfs @ 12.72 hrs, Volume= 0.928 af, Atten= 81%, Lag= 286.5 min I Primary = 0.58 cfs @ 12.72 hrs, Volume= 0.928 af Routing by Dyn-Stor-Ind method, Time Span= 0.00-72.00 hrs, dt= 0.06 hrs/ 3 I Peak Elev= 183.70' @ 12.72 hrs Surf.Area= 0.170 ac Storage= 0.559 of Plug-Flow detention time= 1,103.8 min calculated for 0.927 af (85% of inflow) Center-of-Mass det. time= 1,008.9 min ( 1,729.4 - 720.5 ) I Volume Invert Avail.Storage Storage Description #1A 179.81' 0.000 of 16.00'W x 464.00'L x 4.58'H Field A I 0.781 of Overall - 0.781 of Embedded = 0.000 af x 30.0% Voids #2A 179.81' 0.575 of OldcastleStorm_Capture SC1 4 x 58 Inside #1 Inside= 84._0"W x 48.0"H => 27.38 sf x 16.00'L = 438.0 cf I Outside= 96.0"W x 55.0"H => 36.67 sf x 16.00'L = 586.7 cf 2 Rows adjusted for 360.0 cf perimeter wall 0.575 of Total Available Storage Storage Group A created with Chamber Wizard I North 17052 FinalDesign Type IA 24-hr 10yr Rainfall=3.45" Prepared by Otak, Inc. Printed 2/22/2018 HydroCAD® 10.00-14 s/n 05775 ©2015 HydroCAD Software Solutions LLC Page 7 Device Routing Invert Outlet Devices ' #1 Primary 179.81' 12.0" Round RCP Round 12" L= 50.0' RCP, sq.cut end projecting, Ke= 0.500 Inlet/Outlet Invert= 179.81' / 179.31' S= 0.0100 '/' Cc= 0.900 1 n= 0.013 Concrete pipe, bends & connections, Flow Area= 0.79 sf #2 Device 1 179.81' 1.6" Vert. Orifice/Grate C= 0.600 #3 Device 1 183.60' 5.0' long x 0.5' breadth Broad-Crested Rectangular Weir ' Head (feet) 0.20 0.40 0.60 0.80 1.00 Coef. (English) 2.80 2.92 3.08 3.30 3.32 Primary OutFlow Max=0.58 cfs @ 12.72 hrs HW=183.70' TW=0.00' (Dynamic Tailwater) 1 L1-RCP Round 12" (Passes 0.58 cfs of 6.62 cfs potential flow) -2=Orifice/Grate (Orifice Controls 0.13 cfs @ 9.42 fps) 3=Broad-Crested Rectangular Weir (Weir Controls 0.45 cfs @ 0.89 fps) Summary for Pond 12P: POC - Post-North ' Inflow Area= Inflow 6.160 ac, 46.27% Impervious, Inflow Depth > 2.00" for 10yr event 0.63 cfs @ 12.69 hrs, Volume= 1.028 af Primary = 0.63 cfs @ 12.69 hrs, Volume= 1.028 af, Atten= 0%, Lag= 0.0 min Routing by Dyn-Stor-Ind method, Time Span= 0.00-72.00 hrs, dt= 0.06 hrs/3 I I I North 17052_FinalDesign Type IA 24-hr 25yr Rainfall=3.90" Prepared by Otak, Inc. Printed 2/22/2018 HydroCAD® 10.00-14 s/n 05775 ©2015 HydroCAD Software Solutions LLC Page 8 Summary for Subcatchment 1S: Pre-dev - North Residential Runoff = 1.02 cfs @ 8.20 hrs, Volume= 0.686 af, Depth= 1.46" 1 Runoff by SBUH method, Split Pervious/Imperv., Time Span= 0.00-72.00 hrs, dt= 0.06 hrs Type IA 24-hr 25yr Rainfall=3.90" Area (ac) CN Description 5.650 73 Woods, Fair, HSG C ' 5.650 73 100.00% Pervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 35.1 Direct Entry, Summary for Subcatchment 2S: Pre-dev Hunziker Runoff = 0.11 cfs @ 8.08 hrs, Volume= 0.062 af, Depth= 1.46" , Runoff by SBUH method, Split Pervious/Imperv., Time Span= 0.00-72.00 hrs, dt= 0.06 hrs Type IA 24-hr 25yr Rainfall=3.90" Area (ac) CN Description 0.510 73 Woods, Fair, HSG C 0.510 73 100.00% Pervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 21.5 Direct Entry, Summary for Subcatchment 8S: Post-dev North Residential ' Runoff = 3.68 cfs @ 7.94 hrs, Volume= 1.273 af, Depth= 2.70" Runoff by SBUH method, Split Pervious/lmperv., Time Span= 0.00-72.00 hrs, dt= 0.06 hrs ' Type IA 24-hr 25yr Rainfall=3.90" Area (ac) CN Description , 2.600 98 Paved parking, HSG C 3.050 79 50-75% Grass cover, Fair, HSG C 5.650 88 Weighted Average 3.050 79 53.98% Pervious Area 2.600 98 46.02% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 5.0 Direct Entry, I I North I 17052 FinalDesign Type IA 24-hr 25yr Rainfall=3.90" Prepared by Otak, Inc. Printed 2/22/2018 IHydroCAD® 10.00-14 s/n 05775 ©2015 HydroCAD Software Solutions LLC Page 9 Summary for Subcatchment 9S: Post-dev Hunziker IRunoff = 0.34 cfs @ 7.94 hrs, Volume= 0.117 af, Depth= 2.76" Runoff by SBUH method, Split Pervious/Imperv., Time Span= 0.00-72.00 hrs, dt= 0.06 hrs I Type IA 24-hr 25yr Rainfall=3.90" Area (ac) CN Description I 0.250 98 Paved parking, HSG C 0.260 79 50-75% Grass cover, Fair, HSG C 0.510 88 Weighted Average I 0.260 79 50.98% Pervious Area 0.250 98 49.02% Impervious Area Tc Length Slope Velocity Capacity Description I (min) (feet) (ft/ft) (ft/sec) (cfs) 5.0 Direct Entry, ISummary for Pond 10P: POC - Pre-North Inflow Area = 6.160 ac, 0.00% Impervious, Inflow Depth = 1.46" for 25yr event I Inflow = 1.13 cfs @ 8.18 hrs, Volume= 0.747 of Primary 1.13 cfs @ 8.18 hrs, Volume= 0.747 af, Atten= 0%, Lag= 0.0 min IRouting by Dyn-Stor-Ind method, Time Span= 0.00-72.00 hrs, dt= 0.06 hrs /3 Summary for Pond 11P: Detention North Residential IInflow Area = 5.650 ac, 46.02% Impervious, Inflow Depth = 2.70" for 25yr event Inflow = 3.68 cfs @ 7.94 hrs, Volume= 1.273 af IOutflow = 0.83 cfs @ 10.83 hrs, Volume= 1.115 af, Atten= 77%, Lag= 173.6 min Primary 0.83 cfs @ 10.83 hrs, Volume= 1.115 af Routing by Dyn-Stor-Ind method, Time Span= 0.00-72.00 hrs, dt= 0.06 hrs/3 ' Peak Elev= 183.74' @ 10.83 hrs Surf.Area= 0.170 ac Storage= 0.564 af Plug-Flow detention time= 943.0 min calculated for 1.115 of (88% of inflow) ICenter-of-Mass det. time= 859.2 min ( 1,575.8 - 716.5 ) Volume Invert Avail.Storage Storage Description #1A 179.81' 0.000 af 16.00'W x 464.00'L x 4.58'H Field A I 0.781 af Overall - 0.781 af Embedded = 0.000 af x 30.0% Voids #2A 179.81' 0.575 af Oldcastle_Storm_Capture SC1 4 x 58 Inside#1 Inside= 84.0"W x 48.0"H => 27.38 sf x 16.00'L = 438.0 cf I Outside= 96.0"W x 55.0"H => 36.67 sf x 16.00'L = 586.7 cf 2 Rows adjusted for 360.0 cf perimeter wall 0.575 af Total Available Storage IStorage Group A created with Chamber Wizard 1 North 17052_FinalDesign Type IA 24-hr 25yr Rainfall=3.90" Prepared by Otak, Inc. Printed 2/22/2018 HydroCAD® 10.00-14 s/n 05775 ©2015 HydroCAD Software Solutions LLC Page 10 Device Routing Invert Outlet Devices #1 Primary 179.81' 12.0" Round RCP Round 12" L= 50.0' RCP, sq.cut end projecting, Ke= 0.500 Inlet/ Outlet Invert= 179.81' / 179.31' S= 0.0100 '/' Cc= 0.900 n= 0.013 Concrete pipe, bends & connections, Flow Area= 0.79 sf #2 Device 1 179.81' 1.6" Vert. Orifice/Grate C= 0.600 #3 Device 1 183.60' 5.0' long x 0.5' breadth Broad-Crested Rectangular Weir Head (feet) 0.20 0.40 0.60 0.80 1.00 Coef. (English) 2.80 2.92 3.08 3.30 3.32 Primary OutFlow Max=0.83 cfs @ 10.83 hrs HW=183.74' TW=0.00' (Dynamic Tailwater) L1=RCP_Round 12" (Passes 0.83 cfs of 6.66 cfs potential flow) -2=Orifice/Grate (Orifice Controls 0.13 cfs @ 9.46 fps) 3=Broad-Crested Rectangular Weir (Weir Controls 0.70 cfs @ 1.03 fps) Summary for Pond 12P: POC - Post-North Inflow Area = 6.160 ac, 46.27% Impervious, Inflow Depth > 2.40" for 25yr event I Inflow = 0.91 cfs @ 10.81 hrs, Volume= 1.232 af Primary = 0.91 cfs @ 10.81 hrs, Volume= 1.232 af, Atten= 0%, Lag= 0.0 min Routing by Dyn-Stor-Ind method, Time Span= 0.00-72.00 hrs, dt= 0.06 hrs/ 3 1 1 1 1 I I I I I I I I (38S) KV \24 S) \C 6S) f\40S1 t\28S 1 �14Sj (22S) Pre-dev-Sout Pre--d v Wall Pr-dev Employment Post-d South Post-dev Resi olio! Post-des Wallldet Post-:ev Wall under Past-devv plloyment Residential Resi ential under i A 7P 13 POC-Pre-South Detention South Detention Employment Residential I 2yr=0.93cfs; I/19 10yr=2.58cfs; 25yr=3.52cfs POC-Post-South I 2yr=0.90cfs; 10yr=2.07cfs; 25yr=3.49cfs I I I I I I I Subcat Reach Pon Mill Routing Diagram for 17052_FinalDesign Prepared by Otak, Inc., Printed 2/15/2018 HydroCADO 10.00-14 s/n 05775 ©2015 HydroCAD Software Solutions LLC I South 17052_Final Design Type IA 24-hr 2yr Rainfall=2.50" Prepared by Otak, Inc. Printed 2/15/2018 HydroCAD® 10.00-14 s/n 05775 ©2015 HydroCAD Software Solutions LLC Page 2 Summary for Subcatchment 6S: Post-dev South Residential Runoff = 2.24 cfs @ 7.95 hrs, Volume= 0.819 af, Depth= 1.47" 1 Runoff by SBUH method, Split Pervious/Imperv., Time Span= 0.00-72.00 hrs, dt= 0.06 hrs Type IA 24-hr 2yr Rainfall=2.50" Area (ac) CN Description 3.460 98 Paved parking, HSG C 1 3.240 74 >75% Grass cover, Good, HSG C 6.700 86 Weighted Average 3.240 74 48.36% Pervious Area 3.460 98 51.64% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 5.0 Direct Entry, Summary for Subcatchment 14S: Post-dev Wall undet ' Runoff = 0.29 cfs @ 7.94 hrs, Volume= 0.101 af, Depth= 1.63" Runoff by SBUH method, Split Pervious/lmperv., Time Span= 0.00-72.00 hrs, dt= 0.06 hrs Type IA 24-hr 2yr Rainfall=2.50" Area (ac) CN Description 0.370 98 Paved parking, HSG D 0.090 74 >75% Grass cover, Good, HSG C 0.280 84 50-75% Grass cover, Fair, HSG D 0.740 90 Weighted Average 0.370 82 50.00% Pervious Area 0.370 98 50.00% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 5.0 Direct Entry, Summary for Subcatchment 22S: Post-dev Employment 1 Runoff = 2.17 cfs @ 7.93 hrs, Volume= 0.754 af, Depth= 1.74" Runoff by SBUH method, Split Pervious/Imperv., Time Span= 0.00-72.00 hrs, dt= 0.06 hrs Type IA 24-hr 2yr Rainfall=2.50" I South I 17052 FinalDesign Type lA 24-hr 2yr Rainfall=2.50" Prepared by Otak, Inc. Printed 2/15/2018 IHydroCAD® 10.00-14 s/n 05775 ©2015 HydroCAD Software Solutions LLC Page 3 Area (ac) CN Description 3.540 98 Paved parking, HSG C I1.660 74 >75% Grass cover, Good, HSG C 5.200 90 Weighted Average 1.660 74 31.92% Pervious Area I3.540 98 68.08% Impervious Area Tc Length Slope Velocity Capacity Description I (min) (feet) (ft/ft) (ft/sec) 5.0 (cfs) Direct Entry, ISummary for Subcatchment 24S: Pre-dev Employment Runoff = 0.23 cfs @ 8.85 hrs, Volume= 0.246 af, Depth= 0.57" IRunoff by SBUH method, Split Pervious/Imperv., Time Span= 0.00-72.00 hrs, dt= 0.06 hrs Type IA 24-hr 2yr Rainfall=2.50" IArea (ac) CN Description 5.200 73 Woods, Fair, HSG C 5.200 73 100.00% Pervious Area ITc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) I32.4 Direct Entry, Summary for Subcatchment 27S: Pre-dev Wall IRunoff = 0.41 cfs @ 8.24 hrs, Volume= 0.313 af, Depth= 0.79" I Runoff by SBUH method, Split Pervious/lmperv., Time Span= 0.00-72.00 hrs, dt= 0.06 hrs Type IA 24-hr 2yr Rainfall=2.50" Area (ac) CN Description 1 1.170 73 Woods, Fair, HSG C 3.600 79 Woods, Fair, HSG D 4.770 78 Weighted Average 1 4.770 78 100.00% Pervious Area Tc Length Slope Velocity Capacity Description I (min) (feet) (ft/ft) (ft/sec) (cfs) 33.3 Direct Entry, South 17052_FinalDesign Type IA 24-hr 2yr Rainfall=2.50" Prepared by Otak, Inc. Printed 2/15/2018 HydroCAD® 10.00-14 s/n 05775 ©2015 HydroCAD Software Solutions LLC Page 4 Summary for Subcatchment 28S: Post-dev Wall det Runoff = 1.25 cfs @ 7.96 hrs, Volume= 0.455 af, Depth= 1.35" I Runoff by SBUH method, Split Pervious/Imperv., Time Span= 0.00-72.00 hrs, dt= 0.06 hrs Type IA 24-hr 2yr Rainfall=2.50" Area (ac) CN Description 1.250 98 Paved parking, HSG D 0.700 74 >75% Grass cover, Good, HSG C 2.080 84 50-75% Grass cover, Fair, HSG D 4.030 87 Weighted Average 2.780 81 68.98% Pervious Area 1.250 98 31.02% Impervious Area Tc Length Slope Velocity Capacity Description I (min) (feet) (ft/ft) (ft/sec) (cfs) 5.0 Direct Entry, Summary for Subcatchment 38S: Pre-dev - South Residential Runoff = 0.31 cfs @ 8.84 hrs, Volume= 0.326 af, Depth= 0.57" , Runoff by SBUH method, Split Pervious/Imperv., Time Span= 0.00-72.00 hrs, dt= 0.06 hrs Type IA 24-hr 2yr Rainfall=2.50" Area (ac) CN Description 6.890 73 Woods, Fair, HSG C 6.890 73 100.00% Pervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 32.3 Direct Entry, Summary for Subcatchment 40S: Post-dev Residential undet ' Runoff = 0.09 cfs @ 7.91 hrs, Volume= 0.032 af, Depth= 2.01" Runoff by SBUH method, Split Pervious/Imperv., Time Span= 0.00-72.00 hrs, dt= 0.06 hrs Type IA 24-hr 2yr Rainfall=2.50" Area (ac) CN Description 0.160 98 Paved parking, HSG D 0.030 74 >75% Grass cover, Good, HSG C 0.190 94 Weighted Average 0.030 74 15.79% Pervious Area 0.160 98 84.21% Impervious Area 1 I I 17052 FinalDesign South Type IA 24-hr 2yr Rainfall=2.50" Prepared by Otak, Inc. Printed 2/15/2018 HydroCAD® 10.00-14 s/n 05775 ©2015 HydroCAD Software Solutions LLC Page 5 I Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) I5.0 Direct Entry, Summary for Pond 7P: Detention South Residential IInflow Area = 6.700 ac, 51.64% Impervious, Inflow Depth = 1.47" for 2yr event Inflow = 2.24 cfs @ 7.95 hrs, Volume= 0.819 af I Outflow = 0.32 cfs @ 20.19 hrs, Volume= 0.818 af, Atten= 86%, Lag= 734.5 min Primary 0.32 cfs @ 20.19 hrs, Volume= 0.818 of Routing by Dyn-Stor-Ind method, Time Span= 0.00-72.00 hrs, dt= 0.06 hrs /3 Peak Elev= 185.14' @ 20.19 hrs Surf.Area= 0.079 ac Storage= 0.370 af Plug-Flow detention time= 668.7 min calculated for 0.817 af (100% of inflow) ICenter-of-Mass det. time= 669.2 min ( 1,389.2 - 720.0 ) Volume Invert Avail.Storage Storage Description I #1A 179.72' 0.000 af 24.00'W x 144.00'L x 6.58'H Field A 0.522 af Overall - 0.522 af Embedded = 0.000 af x 0.0% Voids #2A 179.72' 0.410 af Oldcastle_Storm_Capture SC1 6 x 27 Inside #1 I Inside= 84.0"W x 72.0"H => 42.00 sf x 16.00'L = 672.0 cf Outside= 96.0"W x 79.0"H => 52.67 sf x 16.00'L = 842.7 cf 3 Rows adjusted for 294.0 cf perimeter wall 0.410 af Total Available Storage I Storage Group A created with Chamber Wizard I Device Routing Invert Outlet Devices #1 Primary 179.72' 12.0" Round RCP Round 12" L= 50.0' RCP, sq.cut end projecting, Ke= 0.500 I Inlet/Outlet Invert= 179.72'/ 179.22' S= 0.0100 7' Cc= 0.900 n= 0.013 Concrete pipe, bends & connections, Flow Area= 0.79 sf #2 Device 1 179.72' 2.3" Vert. Orifice/Grate C= 0.600 ' #3 Device 1 185.20' 5.0' long x 0.5' breadth Broad-Crested Rectangular Weir Head (feet) 0.20 0.40 0.60 0.80 1.00 Coef. (English) 2.80 2.92 3.08 3.30 3.32 I Primary OutFlow Max=0.32 cfs @ 20.19 hrs HW=185.14' TW=0.00' (Dynamic Tailwater) L1=RCP Round 12" (Passes 0.32 cfs of 7.98 cfs potential flow) -2=Orifice/Grate (Orifice Controls 0.32 cfs @ 11.11 fps) I 3=Broad-Crested Rectangular Weir ( Controls 0.00 cfs) Summary for Pond 13P: Detention Employment IInflow Area = 5.200 ac, 68.08% Impervious, Inflow Depth = 1.74" for 2yr event Inflow = 2.17 cfs @ 7.93 hrs, Volume= 0.754 of IOutflow = 0.24 cfs @ 22.03 hrs, Volume= 0.751 af, Atten= 89%, Lag= 846.3 min Primary 0.24 cfs @ 22.03 hrs, Volume= 0.751 af I I South 17052_FinalDesign Type IA 24-hr 2yr Rainfall=2.50" Prepared by Otak, Inc. Printed 2/15/2018 HydroCAD® 10.00-14 s/n 05775 ©2015 HydroCAD Software Solutions LLC Page 6 I Routing by Dyn-Stor-Ind method, Time Span= 0.00-72.00 hrs, dt= 0.06 hrs / 3 Peak Elev= 174.55' @ 22.03 hrs Surf.Area= 0.106 ac Storage= 0.410 af Plug-Flow detention time= 937.9 min calculated for 0.751 af (100% of inflow) Center-of-Mass det. time= 934.5 min ( 1,634.1 - 699.6 ) Volume Invert Avail.Storage Storage Description I #1A 170.00' 0.000 af 16.00'W x 288.00'L x 5.58'H Field A 0.591 af Overall - 0.591 af Embedded = 0.000 af x 0.0% Voids ' #2A 170.00' 0.450 af Oldcastle_Storm_Capture SC1 5 x 36 Inside #1 Inside= 84.0"W x 60.0"H => 34.69 sf x 16.00'L = 555.0 cf Outside= 96.0"W x 67.0"H => 44.67 sf x 16.00'L = 714.7 cf I 2 Rows adjusted for 380.0 cf perimeter wall 0.450 af Total Available Storage Storage Group A created with Chamber Wizard I Device Routing Invert Outlet Devices #1 Primary 170.00' 12.0" Round RCP_Round 12" I L= 50.0' RCP, sq.cut end projecting, Ke= 0.500 Inlet/ Outlet Invert= 170.00' / 169.50' S= 0.0100 '/' Cc= 0.900 n= 0.013 Concrete pipe, bends & connections, Flow Area= 0.79 sf I#2 Device 1 170.00' 2.1" Vert. Orifice/Grate C= 0.600 #3 Device 1 174.80' 6.0' long x 0.5' breadth Broad-Crested Rectangular Weir Head (feet) 0.20 0.40 0.60 0.80 1.00 1 Coef. (English) 2.80 2.92 3.08 3.30 3.32 Primary OutFlow Max=0.24 cfs @ 22.03 hrs HW=174.55' TW=0.00' (Dynamic Tailwater) t-1-RCP Round 12" (Passes 0.24 cfs of 7.24 cfs potential flow) I'L2=Orifice/Grate (Orifice Controls 0.24 cfs @ 10.18 fps) 3=Broad-Crested Rectangular Weir ( Controls 0.00 cfs) Summary for Pond 19P: POC - Post-South I Inflow Area = 16.860 ac, 52.08% Impervious, Inflow Depth > 1.53" for 2yr event I Inflow = 0.90 cfs @ 7.98 hrs, Volume= 2.156 af Primary = 0.90 cfs @ 7.98 hrs, Volume= 2.156 af, Atten= 0%, Lag= 0.0 min Routing by Dyn-Stor-Ind method, Time Span= 0.00-72.00 hrs, dt= 0.06 hrs/3 I Summary for Pond 26P: Wall Inflow Area = 4.030 ac, 31.02% Impervious, Inflow Depth = 1.35" for 2yr event I Inflow = 1.25 cfs @ 7.96 hrs, Volume= 0.455 af Outflow = 0.17 cfs @ 22.91 hrs, Volume= 0.455 af, Atten= 87%, Lag= 897.3 min I Primary = 0.17 cfs @ 22.91 hrs, Volume= 0.455 af Routing by Dyn-Stor-Ind method, Time Span= 0.00-72.00 hrs, dt= 0.06 hrs /3 I I I South 17052 FinalDesign Type IA 24-hr 2yr Rainfall=2.50" Prepared by Otak, Inc. Printed 2/15/2018 IHydroCAD® 10.00-14 s/n 05775 ©2015 HydroCAD Software Solutions LLC Page 7 Peak Elev= 160.83' @ 22.91 hrs Surf.Area= 5,963 sf Storage= 8,362 cf I Plug-Flow detention time= (not calculated: outflow precedes inflow) Center-of-Mass det. time= 536.8 min ( 1,292.4 - 755.6 ) I Volume #1 Invert Avail.Storage Storage Description 158.50' 26,430 cf Custom Stage Data(Prismatic) Listed below (Recalc) I Elevation Surf.Area Inc.Store (cubic feet) Cum.Store (feet) (sq ft) (cubic-feet) 158.50 1,280 0 0 159.00 2,260 885 885 I 160.00 4,240 3,250 4,135 161.00 6,320 5,280 9,415 162.00 8,510 7,415 16,830 I163.00 10,690 9,600 26,430 Device Routing Invert Outlet Devices I #1 Primary 157.00' 12.0" Round Culvert L= 11.0' CMP, square edge headwall, Ke= 0.500 Inlet/ Outlet Invert= 157.00'/ 156.94' S= 0.0055 '/' Cc= 0.900 n= 0.013 Concrete pipe, bends & connections, Flow Area= 0.79 sf I #2 Device 1 155.00' 1.8" Vert. Orifice/Grate C= 0.600 #3 Device 1 161.50' 5.0' long x 0.5' breadth Broad-Crested Rectangular Weir Head (feet) 0.20 0.40 0.60 0.80 1.00 ICoef. (English) 2.80 2.92 3.08 3.30 3.32 Primary OutFlow Max=0.17 cfs @ 22.91 hrs HW=160.83' TW=0.00' (Dynamic Tailwater) I L1=Culvert (Passes 0.17 cfs of 6.90 cfs potential flow) AL2=Orifice/Grate (Orifice Controls 0.17 cfs @ 9.42 fps) 3=Broad-Crested Rectangular Weir ( Controls 0.00 cfs) ISummary for Pond 30P: POC - Pre-South Inflow Area= 16.860 ac, 0.00% Impervious, Inflow Depth = 0.63" for 2yr event I Inflow = 0.93 cfs @ 8.37 hrs, Volume= 0.885 af Primary = 0.93 cfs @ 8.37 hrs, Volume= 0.885 af, Atten= 0%, Lag= 0.0 min IRouting by Dyn-Stor-Ind method, Time Span= 0.00-72.00 hrs, dt= 0.06 hrs/3 I I I South 17052_FinalDesign Type IA 24-hr 10yr Rainfall=3.45" Prepared by Otak, Inc. Printed 2/15/2018 HydroCAD® 10.00-14 s/n 05775 ©2015 HydroCAD Software Solutions LLC Page 8 Summary for Subcatchment 6S: Post-dev South Residential Runoff = 3.52 cfs @ 7.94 hrs, Volume= 1.253 af, Depth= 2.24" ' Runoff by SBUH method, Split Pervious/Imperv., Time Span= 0.00-72.00 hrs, dt= 0.06 hrs Type IA 24-hr 10yr Rainfall=3.45" Area (ac) CN Description 3.460 98 Paved parking, HSG C 3.240 74 >75% Grass cover, Good, HSG C 6.700 86 Weighted Average 3.240 74 48.36% Pervious Area 3.460 98 51.64% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 5.0 Direct Entry, Summary for Subcatchment 14S: Post-dev Wall undet ' Runoff = 0.45 cfs @ 7.94 hrs, Volume= 0.153 af, Depth= 2.48" Runoff by SBUH method, Split Pervious/Imperv., Time Span= 0.00-72.00 hrs, dt= 0.06 hrs Type IA 24-hr 10yr Rainfall=3.45" Area (ac) CN Description 0.370 98 Paved parking, HSG D 0.090 74 >75% Grass cover, Good, HSG C 0.280 84 50-75% Grass cover, Fair, HSG D 0.740 90 Weighted Average 0.370 82 50.00% Pervious Area 0.370 98 50.00% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 5.0 Direct Entry, Summary for Subcatchment 22S: Post-dev Employment 1 Runoff = 3.23 cfs @ 7.92 hrs, Volume= 1.116 af, Depth= 2.57" Runoff by SBUH method, Split Pervious/Imperv., Time Span= 0.00-72.00 hrs, dt= 0.06 hrs Type IA 24-hr 10yr Rainfall=3.45" 1 1 — South 17052 FinalDesign Type IA 24-hr 10yr Rainfall=3.45" Prepared by Otak, Inc. Printed 2/15/2018 HydroCAD® 10.00-14 s/n 05775 ©2015 HydroCAD Software Solutions LLC Page 9 Area (ac) CN Description 3.540 98 Paved parking, HSG C 1.660 74 >75% Grass cover, Good, HSG C 5.200 90 Weighted Average 1.660 74 31.92% Pervious Area 3.540 98 68.08% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 5.0 Direct Entry, ' Summary for Subcatchment 24S: Pre-dev Employment Runoff = 0.70 cfs @ 8.21 hrs, Volume= 0.497 af, Depth= 1.15" ' Runoff by SBUH method, Split Pervious/Imperv., Time Span= 0.00-72.00 hrs, dt= 0.06 hrs Type IA 24-hr 10yr Rainfall=3.45" ' Area (ac) CN Description 5.200 73 Woods, Fair, HSG C 5.200 73 100.00% Pervious Area ' Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 32.4 Direct Entry, Summary for Subcatchment 27S: Pre-dev Wall Runoff = 0.96 cfs @ 8.14 hrs, Volume= 0.580 af, Depth= 1.46" Runoff by SBUH method, Split Pervious/lmperv., Time Span= 0.00-72.00 hrs, dt= 0.06 hrs Type IA 24-hr 10yr Rainfall=3.45" Area (ac) CN Description ' 1.170 73 Woods, Fair, HSG C 3.600 79 Woods, Fair, HSG D 4.770 78 Weighted Average 1 4.770 78 100.00% Pervious Area Tc Length Slope Velocity Capacity Description ' (min) (feet) (ft/ft) (ft/sec) (cfs) 33.3 Direct Entry, South 17052_FinalDesign Type IA 24-hr 10yr Rainfall=3.45" Prepared by Otak, Inc. Printed 2/15/2018 HydroCAD® 10.00-14 s/n 05775 ©2015 HydroCAD Software Solutions LLC Page 10 Summary for Subcatchment 28S: Post-dev Wall det Runoff = 2.08 cfs @ 7.95 hrs, Volume= 0.722 af, Depth= 2.15" ' Runoff by SBUH method, Split Pervious/Imperv., Time Span= 0.00-72.00 hrs, dt= 0.06 hrs Type IA 24-hr 10yr Rainfall=3.45" Area (ac) CN Description 1.250 98 Paved parking, HSG D ' 0.700 74 >75% Grass cover, Good, HSG C 2.080 84 50-75% Grass cover, Fair, HSG D 4.030 87 Weighted Average 2.780 81 68.98% Pervious Area 1.250 98 31.02% Impervious Area Tc Length Slope Velocity Capacity Description 1 (min) (feet) (ft/ft) (ft/sec) (cfs) 5.0 Direct Entry, Summary for Subcatchment 38S: Pre-dev - South Residential Runoff = 0.92 cfs @ 8.21 hrs, Volume= 0.658 af, Depth= 1.15" ' Runoff by SBUH method, Split Pervious/Imperv., Time Span= 0.00-72.00 hrs, dt= 0.06 hrs Type IA 24-hr 10yr Rainfall=3.45" ' Area (ac) CN Description 6.890 73 Woods, Fair, HSG C 6.890 73 100.00% Pervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 32.3 Direct Entry, Summary for Subcatchment 40S: Post-dev Residential undet 1 Runoff = 0.14 cfs @ 7.91 hrs, Volume= 0.046 af, Depth= 2.90" Runoff by SBUH method, Split Pervious/Imperv., Time Span= 0.00-72.00 hrs, dt= 0.06 hrs Type IA 24-hr 10yr Rainfall=3.45" Area (ac) CN Description 0.160 98 Paved parking, HSG D 0.030 74 >75% Grass cover, Good, HSG C 0.190 94 Weighted Average 0.030 74 15.79% Pervious Area 0.160 98 84.21% Impervious Area I I South 17052 FinalDesign Type IA 24-hr 10yr Rainfall=3.45" Prepared by Otak, Inc. Printed 2/15/2018 HydroCADO 10.00-14 s/n 05775 ©2015 HydroCAD Software Solutions LLC Page 11 I Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 1 5.0 Direct Entry, Summary for Pond 7P: Detention South Residential IInflow Area = 6.700 ac, 51.64% Impervious, Inflow Depth = 2.24" for 10yr event Inflow = 3.52 cfs @ 7.94 hrs, Volume= 1.253 of I Outflow = Primary = 1.30 cfs @ 8.87 hrs, Volume= 1.252 af, Atten= 63%, Lag= 55.9 min 1.30 cfs @ 8.87 hrs, Volume= 1.252 af I Routing by Dyn-Stor-Ind method, Time Span= 0.00-72.00 hrs, dt= 0.06 hrs/3 Peak Elev= 185.37' @ 8.87 hrs Surf.Area= 0.079 ac Storage= 0.386 af Plug-Flow detention time= 487.7 min calculated for 1.251 af (100% of inflow) ICenter-of-Mass det. time= 488.7 min ( 1,202.7 - 714.0 ) Volume Invert Avail.Storage Storage Description I #1A 179.72' 0.000 af 24.00'W x 144.00'L x 6.58'H Field A 0.522 af Overall - 0.522 af Embedded = 0.000 af x 0.0% Voids #2A 179.72' 0.410 af Oldcastle_Storm_Capture SC1 6 x 27 Inside#1 I Inside= 84.0"W x 72.0"H => 42.00 sf x 16.00'L = 672.0 cf Outside= 96.0"W x 79.0"H => 52.67 sf x 16.00'L = 842.7 cf 3 Rows adjusted for 294.0 cf perimeter wall 0.410 of Total Available Storage IStorage Group A created with Chamber Wizard I Device Routing Invert Outlet Devices #1 Primary 179.72' 12.0" Round RCP_Round 12" L= 50.0' RCP, sq.cut end projecting, Ke= 0.500 I Inlet/Outlet Invert= 179.72' / 179.22' S= 0.0100 '/' Cc= 0.900 n= 0.013 Concrete pipe, bends & connections, Flow Area= 0.79 sf #2 Device 1 179.72' 2.3" Vert. Orifice/Grate C= 0.600 #3 Device 1 185.20' 5.0' long x 0.5' breadth Broad-Crested Rectangular Weir I Head (feet) 0.20 0.40 0.60 0.80 1.00 Coef. (English) 2.80 2.92 3.08 3.30 3.32 I Primary OutFlow Max=1.30 cfs @ 8.87 hrs HW=185.37' TW=0.00' (Dynamic Tailwater) t-1=RCP Round 12" (Passes 1.30 cfs of 8.16 cfs potential flow) 4L2=Orifice/Grate (Orifice Controls 0.33 cfs @ 11.35 fps) I3=Broad-Crested Rectangular Weir (Weir Controls 0.98 cfs @ 1.15 fps) Summary for Pond 13P: Detention Employment IInflow Area = 5.200 ac, 68.08% Impervious, Inflow Depth = 2.57" for 10yr event Inflow = 3.23 cfs @ 7.92 hrs, Volume= 1.116 af Outflow = 0.81 cfs @ 9.83 hrs, Volume= 1.112 af, Atten= 75%, Lag= 114.1 min 1 Primary = 0.81 cfs @ 9.83 hrs, Volume= 1.112 af t South 17052_FinalDesign Type IA 24-hr 10yr Rainfall=3.45" Prepared by Otak, Inc. Printed 2/15/2018 HydroCAD® 10.00-14 s/n 05775 ©2015 HydroCAD Software Solutions LLC Page 12 Routing by Dyn-Stor-Ind method, Time Span= 0.00-72.00 hrs, dt= 0.06 hrs/3 Peak Elev= 174.90' @ 9.83 hrs Surf.Area= 0.106 ac Storage= 0.441 af Plug-Flow detention time= 731.5 min calculated for 1.112 af (100% of inflow) Center-of-Mass det. time= 728.9 min ( 1,422.0 - 693.1 ) Volume Invert Avail.Storage Storage Description 1 #1 A 170.00' 0.000 af 16.00'W x 288.00'L x 5.58'H Field A 0.591 af Overall - 0.591 af Embedded = 0.000 af x 0.0% Voids #2A 170.00' 0.450 af Oldcastle_Storm_Capture SC1 5 x 36 Inside #1 Inside= 84.0"W x 60.0"H => 34.69 sf x 16.00'L = 555.0 cf Outside= 96.0"W x 67.0"H => 44.67 sf x 16.00'L = 714.7 cf 2 Rows adjusted for 380.0 cf perimeter wall 0.450 af Total Available Storage Storage Group A created with Chamber Wizard , Device Routing Invert Outlet Devices #1 Primary 170.00' 12.0" Round RCP Round 12" L= 50.0' RCP, sq.cut end projecting, Ke= 0.500 Inlet/Outlet Invert= 170.00' / 169.50' S= 0.0100 '/' Cc= 0.900 n= 0.013 Concrete pipe, bends & connections, Flow Area= 0.79 sf #2 Device 1 170.00' 2.1" Vert. Orifice/Grate C= 0.600 #3 Device 1 174.80' 6.0' long x 0.5' breadth Broad-Crested Rectangular Weir Head (feet) 0.20 0.40 0.60 0.80 1.00 Coef. (English) 2.80 2.92 3.08 3.30 3.32 Primary OutFlow Max=0.81 cfs @ 9.83 hrs HW=174.90' TW=0.00' (Dynamic Tailwater) L1=RCP Round 12" (Passes 0.81 cfs of 7.55 cfs potential flow) t2=Orifice/Grate (Orifice Controls 0.25 cfs @ 10.57 fps) 3=Broad-Crested Rectangular Weir (Weir Controls 0.55 cfs @ 0.90 fps) Summary for Pond 19P: POC - Post-South ' Inflow Area = 16.860 ac, 52.08% Impervious, Inflow Depth > 2.34" for 10yr event Inflow = 2.07 cfs @ 9.74 hrs, Volume= 3.284 af Primary = 2.07 cfs @ 9.74 hrs, Volume= 3.284 af, Atten= 0%, Lag= 0.0 min Routing by Dyn-Stor-Ind method, Time Span= 0.00-72.00 hrs, dt= 0.06 hrs / 3 ' Summary for Pond 26P: Wall Inflow Area = 4.030 ac, 31.02% Impervious, Inflow Depth = 2.15" for 10yr event Inflow = 2.08 cfs @ 7.95 hrs, Volume= 0.722 af Outflow = 0.38 cfs @ 14.72 hrs, Volume= 0.722 af, Atten= 82%, Lag= 405.9 min Primary = 0.38 cfs @ 14.72 hrs, Volume= 0.722 af Routing by Dyn-Stor-Ind method, Time Span= 0.00-72.00 hrs, dt= 0.06 hrs/ 3 1 I I 17052_FinalDesign South Type IA 24-hr 10yr Rainfall=3.45" Prepared by Otak, Inc. Printed 2/15/2018 IHydroCAD® 10.00-14 s/n 05775 ©2015 HydroCAD Software Solutions LLC Page 13 Peak Elev= 161.56' @ 14.72 hrs Surf.Area= 7,541 sf Storage= 13,280 cf I Plug-Flow detention time= 658.2 min calculated for 0.721 af (100% of inflow) Center-of-Mass det. time= 658.9 min ( 1,400.1 - 741.1 ) I Volume #1 Invert Avail.Storage Storage Description 158.50' 26,430 cf Custom Stage Data (Prismatic) Listed below (Recalc) I Elevation Surf.Area Inc.Store (cubic feet) Cum.Store (feet) (sq ft) (cubic-feet) 158.50 1,280 0 0 159.00 2,260 885 885 I160.00 4,240 3,250 4,135 161.00 6,320 5,280 9,415 162.00 8,510 7,415 16,830 1 163.00 10,690 9,600 26,430 Device Routing Invert Outlet Devices I #1 Primary 157.00' 12.0" Round Culvert L= 11.0' CMP, square edge headwall, Ke= 0.500 Inlet/Outlet Invert= 157.00'/ 156.94' S= 0.0055 '/' Cc= 0.900 I n= 0.013 Concrete pipe, bends & connections, Flow Area= 0.79 sf #2 Device 1 155.00' 1.8" Vert. Orifice/Grate C= 0.600 #3 Device 1 161.50' 5.0' long x 0.5' breadth Broad-Crested Rectangular Weir Head (feet) 0.20 0.40 0.60 0.80 1.00 ICoef. (English) 2.80 2.92 3.08 3.30 3.32 Primary OutFlow Max=0.38 cfs @ 14.72 hrs HW=161.56' TW=0.00' (Dynamic Tailwater) I L1=Culvert (Passes 0.38 cfs of 7.62 cfs potential flow) L2=Orifice/Grate (Orifice Controls 0.18 cfs @ 10.28 fps) 3=Broad-Crested Rectangular Weir (Weir Controls 0.19 cfs @ 0.67 fps) ISummary for Pond 30P: POC - Pre-South IInflow Area= 16.860 ac, 0.00% Impervious, Inflow Depth = 1.23" for 10yr event Inflow = 2.58 cfs @ 8.18 hrs, Volume= 1.735 of Primary = 2.58 cfs @ 8.18 hrs, Volume= 1.735 af, Atten= 0%, Lag= 0.0 min 1 Routing by Dyn-Stor-Ind method, Time Span= 0.00-72.00 hrs, dt= 0.06 hrs / 3 I I I I 1 South 17052_FinalDesign Type IA 24-hr 25yr Rainfall=3.90" Prepared by Otak, Inc. Printed 2/15/2018 HydroCAD® 10.00-14 s/n 05775 ©2015 HydroCAD Software Solutions LLC Page 14 Summary for Subcatchment 6S: Post-dev South Residential Runoff = 4.17 cfs @ 7.94 hrs, Volume= 1.468 af, Depth= 2.63" 1 Runoff by SBUH method, Split Pervious/Imperv., Time Span= 0.00-72.00 hrs, dt= 0.06 hrs Type IA 24-hr 25yr Rainfall=3.90" Area (ac) CN Description 3.460 98 Paved parking, HSG C 3.240 74 >75% Grass cover, Good, HSG C 6.700 86 Weighted Average 3.240 74 48.36% Pervious Area 3.460 98 51.64% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 5.0 Direct Entry, Summary for Subcatchment 14S: Post-dev Wall undet 1 Runoff = 0.52 cfs @ 7.93 hrs, Volume= 0.178 af, Depth= 2.89" Runoff by SBUH method, Split Pervious/Imperv., Time Span= 0.00-72.00 hrs, dt= 0.06 hrs Type IA 24-hr 25yr Rainfall=3.90" Area (ac) CN Description 0.370 98 Paved parking, HSG D 0.090 74 >75% Grass cover, Good, HSG C 0.280 84 50-75% Grass cover, Fair, HSG D 0.740 90 Weighted Average 0.370 82 50.00% Pervious Area 0.370 98 50.00% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 5.0 Direct Entry, Summary for Subcatchment 22S: Post-dev Employment 1 Runoff = 3.75 cfs @ 7.92 hrs, Volume= 1.292 af, Depth= 2.98" Runoff by SBUH method, Split Pervious/Imperv., Time Span= 0.00-72.00 hrs, dt= 0.06 hrs Type IA 24-hr 25yr Rainfall=3.90" I I I ' 17052 FinalDesign South Type lA 24-hr 25yr Rainfall=3.90" Prepared by Otak, Inc. Printed 2/15/2018 HydroCAD® 10.00-14 s/n 05775 ©2015 HydroCAD Software Solutions LLC Page 15 Area (ac) CN Description ' 3.540 98 Paved parking, HSG C 1.660 74 >75% Grass cover, Good, HSG C 5.200 90 Weighted Average 1.660 74 31.92% Pervious Area ' 3.540 98 68.08% Impervious Area Tc Length Slope Velocity Capacity Description ' (min) (feet) (ft/ft) (ft/sec) 5.0 (cfs) Direct Entry, Summary for Subcatchment 24S: Pre-dev Employment Runoff = 0.97 cfs @ 8.17 hrs, Volume= 0.631 af, Depth= 1.46" Runoff by SBUH method, Split Pervious/Imperv., Time Span= 0.00-72.00 hrs, dt= 0.06 hrs Type IA 24-hr 25yr Rainfall=3.90" Area (ac) CN Description 5.200 73 Woods, Fair, HSG C 5.200 73 100.00% Pervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) ' 32.4 Direct Entry, Summary for Subcatchment 27S: Pre-dev Wall ' Runoff = 1.26 cfs @ 8.12 hrs, Volume= 0.719 af, Depth= 1.81" Runoff by SBUH method, Split Pervious/Imperv., Time Span= 0.00-72.00 hrs, dt= 0.06 hrs Type IA 24-hr 25yr Rainfall=3.90" Area (ac) CN Description ' 1.170 73 Woods, Fair, HSG C 3.600 79 Woods, Fair, HSG D 4.770 78 Weighted Average 4.770 78 100.00% Pervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 33.3 Direct Entry, 1 1 South 17052_FinalDesign Type IA 24-hr 25yr Rainfall=3.90" Prepared by Otak, Inc. Printed 2/15/2018 HydroCAD® 10.00-14 s/n 05775 ©2015 HydroCAD Software Solutions LLC Page 16 Summary for Subcatchment 28S: Post-dev Wall det Runoff = 2.49 cfs @ 7.95 hrs, Volume= 0.854 af, Depth= 2.54" I Runoff by SBUH method, Split Pervious/Imperv., Time Span= 0.00-72.00 hrs, dt= 0.06 hrs Type IA 24-hr 25yr Rainfall=3.90" Area (ac) CN Description 1.250 98 Paved parking, HSG D 0.700 74 >75% Grass cover, Good, HSG C 2.080 84 50-75% Grass cover, Fair, HSG D 4.030 87 Weighted Average 2.780 81 68.98% Pervious Area 1.250 98 31.02% Impervious Area Tc Length Slope Velocity Capacity Description 1 (min) (feet) (ft/ft) (ft/sec) (cfs) 5.0 Direct Entry, Summary for Subcatchment 38S: Pre-dev - South Residential Runoff = 1.29 cfs @ 8.17 hrs, Volume= 0.836 af, Depth= 1.46" 1 Runoff by SBUH method, Split Pervious/Imperv., Time Span= 0.00-72.00 hrs, dt= 0.06 hrs Type IA 24-hr 25yr Rainfall=3.90" Area (ac) CN Description 6.890 73 Woods, Fair, HSG C 6.890 73 100.00% Pervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 32.3 Direct Entry, Summary for Subcatchment 40S: Post-dev Residential undet 1 Runoff = 0.16 cfs @ 7.91 hrs, Volume= 0.053 af, Depth= 3.33" Runoff by SBUH method, Split Pervious/Imperv., Time Span= 0.00-72.00 hrs, dt= 0.06 hrs Type IA 24-hr 25yr Rainfall=3.90" Area (ac) CN Description 0.160 98 Paved parking, HSG D 0.030 74 >75% Grass cover, Good, HSG C 0.190 94 Weighted Average 0.030 74 15.79% Pervious Area 0.160 98 84.21% Impervious Area I I South I 17052 FinalDesign Type IA 24-hr 25yr Rainfall=3.90" Prepared by Otak, Inc. Printed 2/15/2018 IHydroCAD® 10.00-14 s/n 05775 ©2015 HydroCAD Software Solutions LLC Page 17 Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) I5.0 Direct Entry, Summary for Pond 7P: Detention South Residential IInflow Area = 6.700 ac, 51.64% Impervious, Inflow Depth = 2.63" for 25yr event Inflow = 4.17 cfs @ 7.94 hrs, Volume= 1.468 af I Outflow = 2.36 cfs @ 8.28 hrs, Volume= 1.467 af, Atten= 43%, Lag= 20.4 min Primary 2.36 cfs @ 8.28 hrs, Volume= 1.467 of I Routing by Dyn-Stor-Ind method, Time Span= 0.00-72.00 hrs, dt= 0.06 hrs /3 Peak Elev= 185.47' @ 8.28 hrs Surf.Area= 0.079 ac Storage= 0.393 af Plug-Flow detention time= 424.5 min calculated for 1.467 af (100% of inflow) ICenter-of-Mass det. time= 423.8 min ( 1,135.1 - 711.3 ) Volume Invert Avail.Storage Storage Description I #1 A 179.72' 0.000 of 24.00'W x 144.00'L x 6.58'H Field A 0.522 af Overall - 0.522 of Embedded = 0.000 af x 0.0% Voids #2A 179.72' 0.410 af Oldcastle_Storm_Capture SC1 6 x 27 Inside #1 I Inside= 84.0"W x 72.0"H => 42.00 sf x 16.00'L = 672.0 cf Outside= 96.0"W x 79.0"H => 52.67 sf x 16.00'L = 842.7 cf 3 Rows adjusted for 294.0 cf perimeter wall I0.410 af Total Available Storage Storage Group A created with Chamber Wizard I Device Routing Invert Outlet Devices #1 Primary 179.72' 12.0" Round RCP_Round 12" L= 50.0' RCP, sq.cut end projecting, Ke= 0.500 I Inlet/Outlet Invert= 179.72' / 179.22' S= 0.0100 '/' Cc= 0.900 n= 0.013 Concrete pipe, bends & connections, Flow Area= 0.79 sf #2 Device 1 179.72' 2.3" Vert. Orifice/Grate C= 0.600 I #3 Device 1 185.20' 5.0' long x 0.5' breadth Broad-Crested Rectangular Weir Head (feet) 0.20 0.40 0.60 0.80 1.00 Coef. (English) 2.80 2.92 3.08 3.30 3.32 I Primary OutFlow Max=2.36 cfs @ 8.28 hrs HW=185.47' TW=0.00' (Dynamic Tailwater) 4-1=RCP Round 12" (Passes 2.36 cfs of 8.24 cfs potential flow) 12=Orifice/Grate (Orifice Controls 0.33 cfs @ 11.45 fps) I3=Broad-Crested Rectangular Weir (Weir Controls 2.03 cfs @ 1.49 fps) Summary for Pond 13P: Detention Employment IInflow Area = 5.200 ac, 68.08% Impervious, Inflow Depth = 2.98" for 25yr event Inflow = 3.75 cfs @ 7.92 hrs, Volume= 1.292 of Outflow = 1.39 cfs @ 8.79 hrs, Volume= 1.288 af, Atten= 63%, Lag= 52.1 min Primary 1.39 cfs @ 8.79 hrs, Volume= 1.288 of I I South 111 17052_FinalDesign Type IA 24-hr 25yr Rainfall=3.90" Prepared by Otak, Inc. Printed 2/15/2018 HydroCAD® 10.00-14 s/n 05775 ©2015 HydroCAD Software Solutions LLC Page 18 I Routing by Dyn-Stor-Ind method, Time Span= 0.00-72.00 hrs, dt= 0.06 hrs/3 Peak Elev= 174.97' @ 8.79 hrs Surf.Area= 0.106 ac Storage= 0.447 af Plug-Flow detention time= 641.0 min calculated for 1.288 af (100% of inflow) Center-of-Mass det. time= 638.8 min ( 1,329.4 - 690.6 ) I Volume Invert Avail.Storage Storage Description #1A 170.00' 0.000 af 16.00'W x 288.00'L x 5.58'H Field A 0.591 af Overall - 0.591 af Embedded = 0.000 af x 0.0% Voids #2A 170.00' 0.450 af Oldcastle_Storm_Capture SC1 5 x 36 Inside #1 Inside= 84.0"W x 60.0"H => 34.69 sf x 16.00'L = 555.0 cf Outside= 96.0"W x 67.0"H => 44.67 sf x 16.00'L = 714.7 cf 2 Rows adjusted for 380.0 cf perimeter wall 0.450 af Total Available Storage Storage Group A created with Chamber Wizard I Device Routing Invert Outlet Devices #1 Primary 170.00' 12.0" Round RCP_Round 12" I L= 50.0' RCP, sq.cut end projecting, Ke= 0.500 Inlet/Outlet Invert= 170.00'/ 169.50' S= 0.0100 '/' Cc= 0.900 n= 0.013 Concrete pipe, bends & connections, Flow Area= 0.79 sf #2 Device 1 170.00' 2.1"Vert. Orifice/Grate C= 0.600 #3 Device 1 174.80' 6.0' long x 0.5' breadth Broad-Crested Rectangular Weir Head (feet) 0.20 0.40 0.60 0.80 1.00 Coef. (English) 2.80 2.92 3.08 3.30 3.321 Primary OutFlow Max=1.39 cfs @ 8.79 hrs HW=174.97' TW=0.00' (Dynamic Tailwater) L1=RCP Round 12" (Passes 1.39 cfs of 7.60 cfs potential flow) I AL2=Orifice/Grate (Orifice Controls 0.26 cfs @ 10.63 fps) 3=Broad-Crested Rectangular Weir (Weir Controls 1.13 cfs @ 1.14 fps) Summary for Pond 19P: POC - Post-South I Inflow Area = 16.860 ac, 52.08% Impervious, Inflow Depth > 2.73" for 25yr event I Inflow = 3.49 cfs @ 8.73 hrs, Volume= 3.840 af Primary = 3.49 cfs @ 8.73 hrs, Volume= 3.840 af, Atten= 0%, Lag= 0.0 min Routing by Dyn-Stor-Ind method, Time Span= 0.00-72.00 hrs, dt= 0.06 hrs/3 I Summary for Pond 26P: Wall Inflow Area = 4.030 ac, 31.02% Impervious, Inflow Depth = 2.54" for 25yr event Inflow = 2.49 cfs @ 7.95 hrs, Volume= 0.854 af Outflow = 0.54 cfs @ 11.30 hrs, Volume= 0.854 af, Atten= 78%, Lag= 200.9 min I Primary = 0.54 cfs @ 11.30 hrs, Volume= 0.854 af Routing by Dyn-Stor-Ind method, Time Span= 0.00-72.00 hrs, dt= 0.06 hrs/3 I I South 17052 FinalDesign Type lA 24-hr 25yr Rainfall=3.90" Prepared by Otak, Inc. Printed 2/15/2018 HydroCAD® 10.00-14 s/n 05775 ©2015 HydroCAD Software Solutions LLC Page 19 I Peak Elev= 161.59' @ 11.30 hrs Surf.Area= 7,604 sf Storage= 13,497 cf I Plug-Flow detention time= 578.9 min calculated for 0.853 af (100% of inflow) Center-of-Mass det. time= 579.8 min ( 1,315.2 - 735.4 ) I Volume #1 Invert Avail.Storage Storage Description 158.50' 26,430 cf Custom Stage Data(Prismatic) Listed below (Recalc) I Elevation Surf.Area Inc.Store (cubic feet) Cum.Store (feet) (sq ft) (cubic-feet) 158.50 1,280 0 0 159.00 2,260 885 885 I 160.00 4,240 3,250 4,135 161.00 6,320 5,280 9,415 162.00 8,510 7,415 16,830 I163.00 10,690 9,600 26,430 Device Routing Invert Outlet Devices I #1 Primary 157.00' 12.0" Round Culvert L= 11.0' CMP, square edge headwall, Ke= 0.500 Inlet/Outlet Invert= 157.00'/ 156.94' S= 0.0055 '/' Cc= 0.900 n= 0.013 Concrete pipe, bends & connections, Flow Area= 0.79 sf I #2 Device 1 155.00' 1.8" Vert. Orifice/Grate C= 0.600 #3 Device 1 161.50' 5.0' long x 0.5' breadth Broad-Crested Rectangular Weir Head (feet) 0.20 0.40 0.60 0.80 1.00 ICoef. (English) 2.80 2.92 3.08 3.30 3.32 Primary OutFlow Max=0.54 cfs @ 11.30 hrs HW=161.59' TW=0.00' (Dynamic Tailwater) I L1=Culvert (Passes 0.54 cfs of 7.64 cfs potential flow) -2-Orifice/Grate (Orifice Controls 0.18 cfs @ 10.31 fps) 3=Broad-Crested Rectangular Weir (Weir Controls 0.35 cfs @ 0.82 fps) ISummary for Pond 30P: POC - Pre-South Inflow Area = 16.860 ac, 0.00% Impervious, Inflow Depth = 1.56" for 25yr event I Inflow = 3.52 cfs @ 8.15 hrs, Volume= 2.186 of Primary 3.52 cfs @ 8.15 hrs, Volume= 2.186 af, Atten= 0%, Lag= 0.0 min IRouting by Dyn-Stor-Ind method, Time Span= 0.00-72.00 hrs, dt= 0.06 hrs/3 I I CL - 4-) 0 0 0 0 MINI Mil MR =I ill 111111 MIN MN Mil 111111 WIN NIB MIN - Mill Mill HIM I I The Fields Apartments XP-SWMM Layout IProposed Conditions , ,r,„: tr:'s'14':i-i'4', :':1‘'‘''''!7' I y f6�' I I 1111 / ;--f ';',/-?"-'--! Paes 2-4 g 44*1 1 Pages 5 9 „ ,„., „. , ,-Siii,,.:.„.,,,,.., :,,,,tcri:i71,,,,,,,,,.1i, „} . pI ,,,,,,,,,,„ er 1 , ,„„,,,,,„,„,, . ,,,,, ,,, , , .., _,„ . _ _ „ ,_ , .„.„ . ,„ , , ,,,,,,, . ... . , ,,,, ..„. . , . ... , ,. ,,.. ..: , , --,,,,,,-,,,,,,,":,,.:-„:::---„,-,„,„.„,...,,,-.,,.,-.:-.-i-,,,,,,,,,',.:„,,,,,,i.,,,,,i;,,,,,,,,,,,,,:,:,,,,,\:,„.--,,,,,,„,,s„, ,, 111 ....„...........,, .. „.„..„...... .. , ..., ..„,„,„„, „, „,, , , „ , , o ,,,, ..s< ,�� Pages 10-13 I IPage 1of13 XP-SWMM Layout The Fields Apartments Proposed Conditions I SD,1H-11B I Link712 1 1 SDMH-11C Link885 I SDFC-1 B Link726 r r r r f rr Aink725 t r r filet_N_FC 1 Lin k684 Link722 1 1 Page 2of13 , 1 I I XP-SWMM Layout The Fields Apartments I Proposed Conditions I Oet_N_FC 111 0 I ink684 I Link722 1 I 'iet_ _Res ILink721 nk683 I *SFS-1D ILink682 •.t §H-1 E I Link681 Link713 I'', I •MH-1 F SDMH-1 410 SDC0-p1 t Link680 I I I 1 Page 3 of 13 1 XP-SWMM Layout The Fields Apartments Proposed Conditions I Link879 1 •IMH-1H 1 I ink678 ' 1 I .tMH-1J ' • Link677 S-59 SDMH-1M SDH-1 K Link737 S(J 1H- Link676 Lini5 ' Page 4of13 ' I I XP-SWMM Layout 1 The Fields Apartments Proposed Conditions I ' Link677 S59 SDMH-1 K Link737 I Link735 S5(} S51 Li nk686 Link702 • a,7 ink69O Link687 I I '194 Link688 1 ink691 Ink689 Li59 1 ink692 7 I IPage 5 of 13 1 I XP-SWMM Layout The Fields Apartments Proposed Conditions I ink691 I 49 I L nk689 I J4 ink692 Link729 48 I I Link714 ink693 D- ILin€ .- FCMH S47 Lin AA! Link's'' Link700 S41 Mkt_ink694 Link 4 C. S46 tg Link699 542 Link698 S43 ink696 45 I Link697 tit S44 Link696 I I Page 6 of 13 I I I 1 XP-SWMM Layout 1 The Fields Apartments Proposed Conditions Link71 A Det_S Resi Link728 ' Link727 L%etsIrMH ,�/ Link700 Link703 I I I 1 Page 7 of 13 1 1 XP-SWMM Layout The Fields Apartments Proposed Conditions p 1 1 i Link704 1 1 i 1 1 1 Link715 1 1 1 Page 8 of 13 1 1 I XP-SWMM Layout The Fields Apartments Proposed Conditions 1 ' Link715 SOB ' Link716 ' SDCO-CA SDMH-10G Link705 ' Lin' 06 SP H-10F Page 9of13 I XP-SWMM Layout The Fields Apartments Proposed Conditions nk723 ' SDMH-9B , Link720 1 SDH-9C , Link719 ' SDH-9D '. 1 Link718 1 SDMH-9E Page 10 of 13 1 i XP-SWMM Layout The Fields Apartments 1 Proposed Conditions f 1 1 SDFC-10C St _. Sk I-10E ink709 1 Link72 tall FCRa9Fl Link' 9.1 1 1 *� Wall FC — ILin' 30 4'all_Pond L. 1 1 Link723 ' Sl 19H-913 1 Page 11 of 13 1 I 111 XP-SWMM Layout The Fields Apartments I Proposed Conditions I I I I N Y E. I 0-- t J d O ti Y LO C J lL Page 12 of 13 I I ' XP-SWMM Layout ' The Fields Apartments Proposed Conditions SDMH-10G Link705 Lin 06 S .N-10F Lin. 07 SDFC-1003 S j.. LIWVU Link709 Link724 Page 13 of 13 I IIXP-SWMM RUNOFF DATA The Fields Apartments IProposed Conditions ISCS Type I A 25-Year Storm Event XP-SWMM Input Data XP-SWMM Output Data Max. IRainfall Surface Total Area Impervious Curve Tc Intensity Unit Hydrograph Infiltration Runoff I Node Name (ac) % Number (min) (in/hr) Method Depth (in) Flow (cfs) S194 0.29 100 98 5 1.26 Santa Barbara 2.09 0.34 S194 0.51 0 79 5 1.26 Santa Barbara 0.00 0.28 I S38 0.10 100 98 5 1.26 Santa Barbara 2.09 0.12 S38 0.06 0 79 5 1.26 Santa Barbara 0.00 0.03 S41 0.22 100 98 5 1.26 Santa Barbara 2.09 0.26 I S41 0.08 0 79 5 1.26 Santa Barbara 0.00 0.04 S42 0.48 100 98 5 1.26 Santa Barbara 2.09 0.56 I S42 0.46 0 79 5 1.26 Santa Barbara 0.00 0.25 S43 0.04 100 98 5 1.26 Santa Barbara 2.09 0.05 S43 0.02 0 79 5 1.26 Santa Barbara 0.00 0.01 I S44 0.05 100 98 5 1.26 Santa Barbara 2.09 0.06 S44 0.05 0 79 5 1.26 Santa Barbara 0.00 0.03 S45 0.08 100 98 5 1.26 Santa Barbara 2.09 0.09 IS45 0.25 0 79 5 1.26 Santa Barbara 0.00 0.14 S48 0.27 100 98 5 1.26 Santa Barbara 2.09 0.32 S48 0.48 0 79 5 1.26 Santa Barbara 0.00 0.26 S51 0.25 100 98 5 1.26 Santa Barbara 2.09 0.29 S51 0.35 0 79 5 1.26 Santa Barbara 0.00 0.19 IS54 0.53 100 98 5 1.26 Santa Barbara 2.09 0.62 S54 0.07 0 79 5 1.26 Santa Barbara 0.00 0.04 IS56 0.25 100 98 5 1.26 Santa Barbara 2.09 0.29 S56 0.02 0 79 5 1.26 Santa Barbara 0.00 0.01 I S58 0.25 100 98 5 1.26 Santa Barbara 2.09 0.29 S58 0.09 0 79 5 1.26 Santa Barbara 0.00 0.05 S59 0.71 100 98 5 1.26 Santa Barbara 2.09 0.83 IS59 0.80 0 79 5 1.26 Santa Barbara 0.00 0.44 SDC0-01 0.88 100 98 5 1.26 Santa Barbara 2.09 1.03 I SDCO-01 1.72 0 79 5 1.26 Santa Barbara 0.00 0.94 SDCO-6A 0.14 100 98 5 1.26 Santa Barbara 2.09 0.16 SDCO-6A 0.17 0 79 5 1.26 Santa Barbara 0.00 0.09 1 I XP-SWMM RUNOFF DATA I The Fields Apartments I Proposed Conditions SCS Type IA 25-Year Storm Event I XP-SWMM Input Data XP-SWMM Output Data Max. Rainfall Surface Total Area Impervious Curve Tc Intensity Unit Hydrograph Infiltration Runoff i , Node Name (ac) % Number (min) (in/hr) Method Depth (in) Flow (cfs) SDFS-1D 0.74 100 98 5 1.26 Santa Barbara 2.09 0.87 SDFS-1D 0.11 0 79 5 1.26 Santa Barbara 0.00 0.06 SDMH-10F 0.04 100 98 5 1.26 Santa Barbara 2.09 0.05 I SDMH-10F 0.05 0 79 5 1.26 Santa Barbara 0.00 0.03 SDMH-10G 0.08 100 98 5 1.26 Santa Barbara 2.09 0.09 e SDMH-10G 0.09 0 79 5 1.26 Santa Barbara 0.00 0.05 SDMH-11C 0.16 100 98 5 1.26 Santa Barbara 2.09 0.19 SDMH-11C 0.14 0 79 5 1.26 Santa Barbara 0.00 0.08 SDMH-1C 0.36 100 98 5 1.26 Santa Barbara 2.09 0.42 SDMH-1C 0.17 0 79 5 1.26 Santa Barbara 0.00 0.09 SDMH-1H 0.89 100 98 5 1.26 Santa Barbara 2.09 1.04 SDMH-1H 1.18 0 79 5 1.26 Santa Barbara 0.00 0.64 I SDMH-1M 5.57 100 98 5 1.26 Santa Barbara 2.44 6.53 SDMH-1M 3.71 0 79 27 1.26 Santa Barbara 0.00 0.81 SDMH-9C 0.17 100 98 5 1.26 Santa Barbara 2.09 0.20 I SDMH-9C 0.30 0 79 5 1.26 Santa Barbara 0.00 0.16 SDMH-9D 0.13 100 98 5 1.26 Santa Barbara 2.09 0.15 SDMH-9D 0.27 0 79 5 1.26 Santa Barbara 0.00 0.15 Wall Pond 0.46 100 98 5 1.26 Santa Barbara 2.09 0.5- Wall_Pond 0.62 0 79 5 1.26 Santa Barbara 0.00 0.34 1 I I I I 1 1 1 i 1 1 i 1 1 Appendix n d i x E — I n l e t Capacity a c i t P P P Y 1 Calculations 1 1 1 1 1 1 1 1 Utak I Inlet Report IHydraflow Express Extension for Autodesk®AutoCAD®Civil 3D®by Autodesk,Inc. Thursday, Feb 15 2018 LIDA R5.1 ICurb Inlet Calculations Location = Sag Compute by: Known Q ICurb Length (ft) = 2.00 Q (cfs) = 0.78 Throat Height (in) = 6.00 Grate Area (sqft) = -0- Highlighted IGrate Width (ft) = -0- Q Total (cfs) = 0.78 Grate Length (ft) = -0- Q Capt (cfs) = 0.78 Q Bypass (cfs) = -0- IGutter Depth at Inlet (in) = 3.08 Slope, Sw (ft/ft) = 0.026 Efficiency (%) = 100 Slope, Sx (ft/ft) = 0.025 Gutter Spread (ft) = 10.20 ILocal Depr (in) = -0- Gutter Vel (ft/s) = -0- Gutter Width (ft) = 1.50 Bypass Spread (ft) = -0- Gutter Slope (%) = -0- Bypass Depth (in) = -0- ' Gutter n-value = -0- I Iu dmersions ie fe6 f.,28_,, 01° 1 .{ Report eport I Hydraflow Express Extension for Autodesk®AutoCAD®Civil 3D®by Autodesk,Inc. Thursday, Feb 15 2018 1 LIDA R8.2 I Curb Inlet Calculations Location = Sag Compute by: Known Q Curb Length (ft) = 2.00 Q (cfs) = 0.61 Throat Height (in) = 6.00 Grate Area (sgft) = -0- Highlighted Grate Width (ft) = -0- Q Total (cfs) = 0.61 111 Grate Length (ft) = -0- Q Capt (cfs) = 0.61 Q Bypass (cfs) = -0- Gutter Depth at Inlet (in) = 2.61 I Slope, Sw (ft/ft) = 0.045 Efficiency (%) = 100 Slope, Sx (ft/ft) = 0.025 Gutter Spread (ft) = 7.51 I Local Depr (in) = -0- Gutter Vel (ft/s) = -0- Gutter Width (ft) = 1.50 Bypass Spread (ft) = -0- Gutter Slope (%) = -0- Bypass Depth (in) = -0- I Gutter n-value = -0- I 4,11d„»Rrs,ans,nr� I __..............___ r . .,, 00 I zz I 7-7 I I I I Inlet Report IHydraflow Express Extension for Autodesk®AutoCAD®Civil 3D®by Autodesk, Inc. Thursday, Feb 15 2018 LIDA R12.3 ICurb Inlet Calculations Location = Sag Compute by: Known Q ICurb Length (ft) = 2.00 Q (cfs) = 0.28 Throat Height (in) = 6.00 Grate Area (sgft) = -0- Highlighted 1 Grate Width (ft) = -0- Q Total (cfs) = 0.28 Grate Length (ft) = -0- Q Capt (cfs) = 0.28 Q Bypass (cfs) = -0- 1 Gutter Depth at Inlet (in) = 1.55 Slope, Sw (ft/ft) = 0.055 Efficiency (%) = 100 Slope, Sx (ft/ft) = 0.025 Gutter Spread (ft) = 3.38 ILocal Depr (in) = -0- Gutter Vel (ft/s) = -0- Gutter Width (ft) = 1.50 Bypass Spread (ft) = -0- Gutter Slope (%) = -0- Bypass Depth (in) = -0- 1 Gutter n-value = -0- I II dlmer,siors,n feet I . 7 13 Inlet Report Hydraflow Express Extension for Autodesk®AutoCAD®Civil 3D®by Autodesk,Inc. Thursday, Feb 15 2018 I LIDA R15.4 1 Curb Inlet Calculations Location = Sag Compute by: Known Q I Curb Length (ft) = 2.00 Q (cfs) = 0.08 Throat Height (in) = 6.00 Grate Area (sgft) = -0- Highlighted Grate Width (ft) = -0- Q Total (cfs) = 0.08 Grate Length (ft) = -0- Q Capt (cfs) = 0.08 Q Bypass (cfs) _ -0- Gutter Depth at Inlet (in) = 0.67 I Slope, Sw (ft/ft) = 0.027 Efficiency (%) = 100 Slope, Sx (ft/ft) = 0.025 Gutter Spread (ft) = 2.13 I Local Depr (in) = -0- Gutter Vel (ft/s) = -0- Gutter Width (ft) = 1.50 Bypass Spread (ft) _ -0- Gutter Slope (%) = -0- Bypass Depth (in) = -0- I Gutter n-value = -0- I ?At d;mensiuns Sn Fe9 I 1 I 1 I 1. u.`3 P 1 Inlet Report IHydraflow Express Extension for Autodesk®AutoCAD®Civil 3D®by Autodesk, Inc. Thursday, Feb 15 2018 LIDA R16.4 ICurb Inlet Calculations Location = Sag Compute by: Known Q 1 Curb Length (ft) = 2.00 Q (cfs) = 0.14 Throat Height (in) = 6.00 Grate Area (sqft) = -0- Highlighted IGrate Width (ft) = -0- Q Total (cfs) = 0.14 Grate Length (ft) = -0- Q Capt (cfs) = 0.14 Q Bypass (cfs) = -0- 1 Gutter Depth at Inlet (in) = 0.98 Slope, Sw (ft/ft) = 0.023 Efficiency (%) = 100 Slope, Sx (ft/ft) = 0.025 Gutter Spread (ft) = 3.38 ILocal Depr (in) = -0- Gutter Vel (ft/s) = -0- Gutter Width (ft) = 1.50 Bypass Spread (ft) = -0- Gutter Slope (%) = -0- Bypass Depth (in) = -0- ' Gutter n-value = -0- I �tl dmens:on%in feet I PB ISI ' 1.5 1.88 FY Inlet Report I Hydraflow Express Extension for Autodesk®AutoCAD®Civil 3D®by Autodesk, Inc. Thursday, Feb 15 2018 I LIDA R17.4 I Curb Inlet Calculations Location = Sag Compute by: Known Q Curb Length (ft) = 2.00 Q (cfs) = 0.11 Throat Height (in) = 6.00 Grate Area (sqft) = -0- Highlighted I Grate Width (ft) = -0- Q Total (cfs) = 0.11 Grate Length (ft) = -0- Q Capt (cfs) = 0.11 Q Bypass (cfs) = -0- I Gutter Depth at Inlet (in) = 0.83 Slope, Sw (ft/ft) = 0.006 Efficiency (%) = 100 Slope, Sx (ft/ft) = 0.025 Gutter Spread (ft) = 3.92 1 Local Depr (in) = -0- Gutter Vel (ft/s) _ -0- Gutter Width (ft) = 1.50 Bypass Spread (ft) = -0- Gutter Slope (%) _ -0- Bypass Depth (in) = -0- 111 ' Gutter n-value = -0- I ,"-.II tlim ensions in fe8 I I I 1 Com' __._ 4. s I NN I if I I I I 1 Inlet Report IHydraflow Express Extension for Autodesk®AutoCAD®Civil 3D®by Autodesk,Inc. Thursday, Feb 15 2018 LIDA W8.3 ICurb Inlet Calculations Location = Sag Compute by: Known Q ICurb Length (ft) = 2.00 Q (cfs) = 0.13 Throat Height (in) = 6.00 Grate Area (sgft) = -0- Highlighted IGrate Width (ft) = -0- Q Total (cfs) = 0.13 Grate Length (ft) = -0- Q Capt (cfs) = 0.13 Q Bypass (cfs) = -0- IIGutter Depth at Inlet (in) = 0.93 Slope, Sw (ft/ft) = 0.020 Efficiency (%) = 100 Slope, Sx (ft/ft) = 0.025 Gutter Spread (ft) = 3.40 ILocal Depr (in) = -0- Gutter Vel (ft/s) = -0- Gutter Width (ft) = 1.50 Bypass Spread (ft) = -0- Gutter Slope (%) _ -0- Bypass Depth (in) = -0- ' Gutter n-value = -0- I �t!dlmensians in fed I i8 { 1 /'' 1 1 1 I I 1 1 1 1 1 1 1 1 1 Appendix n d i x F — O erations and p p a d 1 Maintenance Plan 1 1 1 1 1 1 1 1 utak 1 1 1 The Fields Apartments 1 Operations & Maintenance Plan 1 for Stormwater Facilities February 20, 2018 1 1 Prepared for: DBG Properties, LLC 2164 SW Park Place ' Portland, OR 97205 1 1 1 1 Prepared by: Otak, Inc. 808 SW Third Avenue ' Suite 300 Portland, Oregon 97204 1 Otak 1 1 1 Otak Stormwater Operations & Maintenance Plan ' The Fields Apartments February 20, 2018 ' Prepared by: Otak, Inc. 808 SW Third Avenue, Suite 300 Portland, OR 97204 Responsibility The privately owned stormwater facilities are to be maintained by DBG Properties. The preparer has designed a system that can be maintained by maintenance staff and contractors. The DBG Properties contact is Melora Banker(503) 816-4084. A copy of the O&M plan shall be provided to all property owners. Description of Stormwater Facilities Runoff from the The Fields Apartments will be collected and conveyed in a storm sewer system and managed with LIDA flow-through planters, rain gardens, a vegetated filter strip, pretreatment water quality manholes, and underground detention systems. Figure 1 shows the location of these facilities on the site plan. The storm sewer in the public right-of-way will be maintained by City of Tigard. Regular inspections and maintenance of the privately owned storm facilities will need to be performed as described below. See attached site plan Figure 1 for locations of each stormwater management feature. LIDA Flow-Through Planters ' There are 29 privately owned LIDA flow-through planters located amongst the multi-family buildings. These planters provide water quality treatment of the rooftop and parking area runoff, allowing sediments and debris to settle out and pollutants to be removed as the stormwater infiltrates through a layer of water quality mix. Beneath ' the water quality mix layer is a gravel layer with a perforated pipe, to collect the treated flows and discharge them to the piped storm sewer system. An overflow structure in the planters will help drain the planter should the stormwater runoff entering the planter exceed the infiltration capacity of the water quality mix. These vegetated ' flow-through planters also have rock energy dissipation pads and vegetation which all require inspection and maintenance to function as designed. L:IProject117000\170521Reports\Stormwater Management PlanlAppendix F-O&M Plan\17052 O&M Plan.docx 1 808 SW Third Avenue,Suite 300,Portland,OR 97204•Phone(503)287-6825 Fax(503)415-2304 otak.com I I Rain Garden Runoff from SW Varns Street and two adjacent properties will be collected and treated in a rain garden. A rain garden is also located between multi-family buildings in the southern portion of the site, which provides water quality treatment of the rooftop and sidewalk. A rain garden allows sediments and debris to settle out and pollutants to be removed as the stormwater infiltrates through a layer of water quality mix. An overflow structure in I the facility will help drain the rain garden should the stormwater runoff entering the facility exceed the infiltration capacity of the water quality mix. Vegetated Filter Strip I Adjacent to the SW 76th Avenue concrete path is a vegetated filter strip. The filter strip provides water quality treatment of the rooftop and parking area runoff, allowing sediments and debris to settle out and pollutants to be removed as the stormwater infiltrates through a layer of water quality mix. Beneath the water quality mix layer is a I gravel layer with a perforated pipe, to collect the treated flows and discharge them to the piped storm sewer system. An overflow structure in the planters will help drain the planter should the stormwater runoff entering the planter exceed the infiltration capacity of the water quality mix. These vegetated flow-through planters also have I rock energy dissipation pads and vegetation which all require inspection and maintenance to function as designed. Detention Vault System I Stormwater runoff from The Fields Apartments development will be treated and detained in two underground detention vault systems. One underground detention vault system will detain stormwater from the North I Residential Basin, while one underground detention vault system will detain stormwater from the South Residential Basin. A flow control manhole downstream of the detention pipes will control release rates to protect the downstream conveyance system from the increase flows resulting from development. The location of the two 1 detention vault systems are shown on Figure 1. Detention system release rates are controlled by structures in the flow control manhole. A weir wall in the flow control manhole with an orifice provides a controlled release of flows from the detention facility to the downstream I conveyance system. Flow Control Manhole Summary I Facility Manhole Orifice Weir Discharge Point r Diameter Diameter Length North Flow Control 72 inches 1.6 inches 72 inches To conveyance system I Manhole South Flow Control 72 inches 2.3 inches 72 inches To conveyance system Manhole I Inspection/Maintenance Schedule Eachprivate facilityshall be inspected and maintained quarterly for the first three years of operation, twice per I p year thereafter, and within 48 hours after a major storm event. For this O&M Plan, a major storm event is defined as 1.0 inches of rainfall in a 24-hour period. All components of the storm system as described above must be I inspected and maintained frequently or they will cease to function effectively. The facility owner shall keep a log, L.1Project1170001170521Reports\Stormwater Management PlanlAppendix F-O&M Plan117052 O&M Plan.docx 2 1 808 SW Third Avenue,Suite 300, Portland,OR 97204•Phone(503)287-6825 Fax(503)415-2304 otak.com I I recording all inspection dates, observations, and maintenance activities. Maintenance Logs are included in Appendix A. Receipts shall be saved when maintenance is performed and there is a record of expense. RECOMMENDED MAINTENANCE CALENDAR (tasks per month) I STORMWATER FACILITY Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec LIDA Flow-Through Planters 1 1 1 1 Rain Garden 1 1 1 1 I Vegetated Filter Strip 1 1 1 1 Detention Vault System 1 1 1 1 I NOTE: Maintenance schedule reflects ongoing maintenance after the first 3 years of facility construction. In the first 3 years, facilities shall be inspected quarterly as well as within 48 hours of a storm event greater than or equal to 1.0 inches of rain during a 24-hour period. IInspection/Maintenance Procedures I Source Control Source Control measures prevent pollutants from mixing with stormwater. Typical non-structural control measures include raking and removing leaves, and limited and controlled application of pesticides, herbicides, and Ifertilizers. • Source control measures shall be inspected and maintained quarterly. I • Signage shall be maintained. • Insects and Rodents shall not be harbored in any part of the storm system. • Pest control measures shall be taken when insects/rodents are found to be present. Standing water and food I sources shall be prevented. • If sprays are considered, a mosquito larvicide such as Bacillus thurendensis or Altoside formulations can be applied only if absolutely necessary and shall not be used where it will enter groundwater or come into I contact with any standing water. Sprays shall be applied only by licensed individuals or contractors. • Holes in the ground located in and around the storm system shall be filled. Access shall be maintained for all facilities so operations and maintenance can be performed as regularly Ischeduled. LIDA Flow-through Planter I See attached O&M Specifications for Flow-through Planters. Rain Garden ISee attached O&M Specifications for Rain Gardens. Vegetated Filter Strip 1 See attached O&M Specifications for Vegetated Filter Strip. Detention Vault System I See attached O&M Specifications for Stormcapture System and Closed Detention System. I L:1Project1170001170521Reports\Stormwater Management PlanlAppendix F-O&M Plan\17052 O&M Plan.docx 3 808 SW Third Avenue,Suite 300,Portland,OR 97204•Phone(503)287-6825 Fax(503)415-2304 otak.com 1 Flow Control Manhole The flow control manhole is vital to protect the upstream system from flooding and the downstream system from high flows due to development. Inspection shall be performed quarterly for the first 2 years, and twice per year thereafter. Structures shall also be inspected within 48 hours of a major rainfall event(more than 1-inch in 24- hours). Inspection and maintenance activities include: • Flow control structures shall be inspected in the fall and spring, monitoring the water level and sediment level in the manhole. • Debris shall be removed from the orifice structures as needed. ' • Orifices, caps, and other mechanical features shall remain intact. Damaged or disconnected parts shall be repaired or replaced in-kind. • Do not use any solvents or chemicals in the flow control manhole. • Remove sediment from the sump when sediment accumulates to level of orifice. • Dewater and dispose of sediment properly. Test sediment that has a heavy oil sheen and/or odors to determine the appropriate disposal. • Maintain the orifices to prevent floatable materials, such as trash and debris, from entering the storm drain system. • Repair/seal cracks. Replace when repair is insufficient. Record the amount of sediment collected and the date of removal in the Maintenance Log. 1 1 1 L:IProject1170001170521Reports\Stormwater Management PIanlAppendix F-O&M Plan117052 O&M Plan.docx 4 808 SW Third Avenue,Suite 300,Portland,OR 97204•Phone(503)287-6825 Fax(503)415-2304 otak.com 1 1 1 1 1 1 i 1 Figures 1 ( Operations & Maintenance ) 1 1 i 1 1 1 1 i Otak 1Sia 1 1 1 I Appendices ' ( Operations & Maintenance ) 1 Otak I 1 I Appendix A : 0 & M Plan Forms ( Operations & Maintenance ) I Otak I IAfter Recording Return to: Clean Water Services I2550 SW Hillsboro Hwy. Hillsboro, OR 97123 I I I PRIVATE STORMWATER FACILITIES AGREEMENT This Agreement is made and entered into this day of 20�by and between Clean Water Services I (District)and (Owner). RECITALS 1 A. Owner has developed or will develop the Facilities listed below. (List the type of private stormwater facilities on site and the quantity of each type). Facility type(list each) Quantity I I B. The Facilities enable development of property while mitigating the impacts of additional surface water and I pollutants associated with stormwater runoff prior to discharge from the property to the public stormwater system. The consideration for this Agreement is connection to the public stormwater system. ' C. The property benefited by the Facilities and subject to the obligation of this Agreement is described below or in Exhibit A(Property)attached hereto and incorporated by reference. I I I D. The Facilities are designed by a registered professional engineer to accommodate the anticipated volume of runoff and to detain and treat runoff in accordance with District's Design and Construction Standards. I E. Failure to inspect and maintain the Facilities can result in an unacceptable impact to the public stormwater system. I 88 Low Impact Development Approaches Handbook C1eanWaterrV Services I NOW,THEREFORE,it is agreed by and between the parties as follows: 1. OWNER INSPECTIONS District shall provide Owner an Operations and Maintenance Plan(O&M Plan)for each Facility. Owner agrees to operate,inspect and maintain each Facility in accordance with the current O&M Plan and any subsequent modifications to the Plan. Owner shall maintain a log of inspection activities. The log shall be available to District upon request or during District inspections. 2. DEFICIENCIES All aspects in which the Facilities fail to satisfy the O&M Plan shall be noted as"Deficiencies". 3. OWNER CORRECTIONS All Deficiencies shall be corrected at Owner's expense within thirty(30) days after completion of the inspection. If more than 30 days is reasonably needed to correct a Deficiency, Owner shall have a reasonable period to correct the Deficiency so long as the correction is commenced within the 30-day period and is diligently prosecuted to completion. 4. DISTRICT INSPECTIONS Owner grants District the right to inspect the Facilities. District will endeavor to give ten(10) days prior written notice to Owner, except that no notice shall be required in case of an emergency. District shall determine whether Deficiencies need to be corrected. Owner(at the address provided at the end of this Agreement,or such other address as Owner may designate in writing to District)will be notified in writing through the US Mail of the Deficiencies and shall make corrections within 30 days of the date of the notice. 5. DISTRICT CORRECTIONS If correction of all Owner or District identified Deficiencies is not completed within thirty(30) days after Owner's inspection or District notice,District shall have the right to have any Deficiencies corrected. District(i) shall have access to the Facilities for the purpose of correcting such Deficiencies and(ii) shall bill Owner for all costs reasonably incurred by District for work performed to correct the Deficiencies(District Correction Costs)following Owner's failure to correct any Deficiencies in the Facilities. Owner shall pay District the District Correction Costs within thirty(30)days of the date of the invoice. Owner understands and agrees that upon non-payment, District Correction Costs shall be secured by a lien on the Property for the District Correction Cost amount plus interest and penalties. 6. EMERGENCY MEASURES If at any time District reasonably determines that the Facilities create any imminent threat to public health, safety or welfare,District may immediately and without prior notice to Owner take measures reasonably designed to remedy the threat. District shall provide notice of the threat and the measures taken to Owner as soon as reasonably practicable, and charge Owner for the cost of these corrective measures. 7. FORCE AND EFFECT This Agreement has the same force and effect as any deed covenant running with the land and shall benefit and bind all owners of the Property present and future, and their heirs, successors and assigns. 8. AMENDMENTS The terms of this Agreement may be amended only by mutual agreement of the parties.Any amendments shall be in writing, shall referspecifically-to-this—Agreement, and shall be valid only when executed by the owners of the Property,District and recorded in the Official_Records of the county where the Property is located. ' 9. PREVAILING PARTY In any action brought by either party to enforce the terms of this Agreement,the prevailing party shall be entitled to recover all costs,including reasonable attorney's fees as may be determined by the court having jurisdiction,including any appeal. 10. SEVERABILITY The invalidity of any section, clause, sentence, or provision of this Agreement shall not affect the validity of any other part of this Agreement,which can be given effect without such invalid part or parts. C1eanWater Services Low Impact Development Approaches Handbook 89 IN WITNESS WHEREOF, Owner and District have signed this Agreement. INOTARIZE DOCUMENT BELOW I INDIVIDUAL OWNERS SIGN BELOW CORPORATE,LLC,PARTNERSHIP, TRUST OR OTHER LEGAL ENTITY SIGN BELOW IOwner(Individual) (Entity name) Owner(Individual) By. (Sign here for entity) ' Title: ICLEAN WATER SERVICES APPROVED AS TO FORM 1 By: General Manager or Designee District Counsel [Use this notary block if OWNER is an individual.] I STATE OF ) ) County of ) IThis instrument was acknowledged before me this day of , 20 , by Notary Public [Use this notary block if OWNER is an entity.] STATE OF ) ) County of ) IThis instrument was acknowledged before me on (date) I. by (name of person) as (title) of (name of entity). Notary Public 90 Low Impact Development Approaches Handbook C1eanWater` Services Operations & Maintenance Plan I Contact List I Owner's Name: DBG Properties, LLC Contact Name: Melora Banker Phone Number: ' (503)816-4084 Owner's Mailing Address: 2164 SW Park Place Portland, OR 97205 Site Address: Site Tax Lot(s): Tax Lot ID 2S1010001600 Party(ies) responsible for maintenance (only if different than Owner): Name: ' Company: Address: I Phone Number: Emergency/After-Hours Contact Information: Name: , Phone Number: I 1 Work Plan Template Submitted by: ISite address: Work performed by: Work starting date: Work ending date: These dates are estimated and may change due to weather or other unforeseen factors. Clean Water I Services will be notified at 503-681-3605 immediately of any changes to this plan. ❑ - Structures to be cleaned between the dates of and I ❑ Water quality manhole ❑ Outfall structure ❑ Catch basins ❑ Filter vault ❑ Filter catch basins ❑ Closed Detention System ❑ Other I ❑ - Vegetation management to occur between the dates of and ❑ Pruning of desirable vegetation [' Remove invasive vegetation ❑ Pruning of desirable vegetation and remove invasive vegetation ❑ No invasive plants I The removal method used will be: ❑ Manually or mechanically remove all invasive vegetation from the facility. I ❑ Use the appropriate herbicide then physically remove the dead vegetation from the facility.* ❑ Spot spray with the appropriate herbicide as necessary.* ❑ No invasive vegetation or other undesirable weeds on corrective maintenance list I ❑ Other: *It may be necessary to repeat this process several times to insure complete eradication of the invasive vegetation. I (see IPM Guidance for specific invasive vegetation, methods and chemicals to use) ❑ - Grading and/or sediment removal will be done between the dates of: and I . Approved plans will be referenced to determine correct slope and elevations. ❑ - Planting and erosion control will be done between the dates of and I . Approved plans will be referenced for plant and/or seed mix requirements. If planting plan is not available contact CWS for guidance. All exposed areas of water quality facilities shall be I protected from erosion. Coconut matting or high density jute matting (Geojute Plus or approved equal) shall be used in the treatment area of swales and below the water quality volume levels of ponds. Low density jute matting (Econojute or approved equal) may be used on all other zones. IClean Water Services will be notified at 503-681-3605 • Immediately of any changes to this plan Signature; I • 48 hours prior to starting work Sign or type name • For inspection when all work is complete Date IInclude other issues or comments on a separate sheet if necessary. I 2550 SW Hillsboro Highway Hillsboro, Oregon 97123 Phone: (503)681-3600 Fax: (503)681-3603 cleanwaterservices.org Clean Waterer Services 1 1 I 1 I I Appendix B : Standard Procedures ( Operations & Maintenance ) I I I I Utak I I i Flow-Through Planter Page 1of4 . , , .‘,., „... „ , .., , .„, , ..., . \ , ,,,,;,..-t-,-. , ' �, , , ,.. ,,-,',,,,z4-N.,, - - 7 4 �, � tit.--t O t � ,, buildings 11014/ i \ ',..aaltt"'. !7',,isZW,W41,,,,,. ...ri,,, ,:i7^41%*',Z.:1'\'';', ',,"k �I parking areas &impermeable � � � � � � landscape � i'r �- as � �y — 'U� Etit a impermeable soils t. i N- s s Course Description Application & Limitations IFlow-through planters are structural landscaped reservoirs that Flow through planters may help fulfill a site's land soaping area collect stormwater and filter out pollutants as the water percolates requirement and can be used to manage stormwater runoff from through the vegetation,growing medium,and gravel.These all types of impervious surfaces on private property and within the are appropriate where soils do not drain well or there are site public •right-of-way.Check with the local jurisdiction if proposing constraints. A liner may be required when located adjacent to to use a flow through planter in the public right-of-way.Flow through buildings,over contaminated soils,and on unstable slopes.Excess planters can be placed next to buildings and are ideal for sites I stormwater collects in a perforated pipe at the bottom of the flow with poorly draining soils,steep slopes or other constraints.Design through planter and drains to an approved discharge point. variations of shape,wall treatment,and planting scheme will fit the character of any site. Tree box filters are flow-through planters with al concrete"box"that I contains filtering growing media and a tree or large shrub.Tree box filters are used singly or in multiples,often adjacent to streets . �� 1 where runoff is directed to them to treat stormwater runoff before it e�o� enters a catch basin. I I I Headwaters at Tryon Creek, Portland 34 Low Impact Development Approaches Handbook C1eanwate�seMces I II Page Flow—Through , s ,.—,.„... sly s,--,,,i ,,,,-, '- , __.„. s , .,„ ,. .--, , „, s ..4„, ,. -. Planter- - -IF -4 -iv...e:' '--:-.: -,--.:.-1,:..tr-,::,351,..-e, II s Structural wall `' " ,,,, --* / ''' 7,7", , ',: \ %,* b' . (with waterproofing) � ' I Downspout : •-.4:17:410,1/41,4, #�Hooded overflow ' "Freeboard sAGravel or splash block "#1.44 $F} I �_ •• f G"Ponding Depth I * , `' ' ems _ 18°Growing M:cu-r ium IPerforated pipe .. , .N ir Y (to run length of planter) . r ; Z ,� _ Foundation drain 3"Choker se Structural footing ° . :' . 9 Drain Rork o I - moi _ -v ' .a r . t-4.-.e-4.%-- �r b r - a._- � a�.,.• ' Design Factors Sizin To calculate the planter size,multiply the imervious surface or adjacent parking lot areas via curb openings. The overflow (rooftops,driveways,parking lots,etc.)area Pby 6%.The square drain allows not more than 6 inches of water to pond in the planter footage is the peak water surface prior to overflow.For example,a prior to overflow.A perforated pipe system under the planter drains 1,200 sf rooftop and 300 sf driveway(1,500 sf total impervious area) water that has filtered through the topsoil to prevent long-term requires a 90 sf stormwater planter(1,500 x 0.06).This could be ponding.On private property,the overflow drain and piping must accomplished with one 9-foot by 10 foot flow through planter. meet Plumbing Code requirements and direct excess and filtered Geometry/Slopes stormwater to an approved disposal point. Check with the local • Stormwater planters may be any shape,and can be jurisdiction or use Clean Water Services Design and Construction designed as square,rectangular,circular,oblong,or Standards for additional information on piping material for use in 1 irregular. the public right-of-way. • Regardless of the shape,a minimum planter width of 30 inches is needed to achieve sufficient time for jt ' t "} : F� 1 treatment and to avoid short-circuiting. ,_ • The minimum treatment depth of 18 inches is achievedi. N in the growing medium. -- • Planters are designed to evenly distribute and filter flows. 4 .,., Surface longitudinal slopes should be less than 0.5%. �« " Piping for Flow Through Planters Follow Plumbing Code requirements for piping that directs , ' stormwater from impervious surfaces to flow through planters. _ E Stormwater may flow directly from the public street right-of-way Portland Rebuilding Center I C1eanWate Services Low Impact Development Approaches Handbook 35 I i Flow-Through Planter Page3of4 1L1 1' j II a 8 :"- _1 ;,,-„,-„:7, ,„ ,,:f41:1 -,---1,,,,,,,0- ,,, I �c 4# x 'm F g ti ' itS�� °, , "tee- � A�'"T \��\\�: �. RiverEast Center,SE Portland I N reduces erosion,and limits the spread of weeds.Appropriate, carefully selected plantings enhance the aesthetic and habitat PSU Stephen Epler Hall, Portland value.For a complete list of allowable plants refer to page 76. I Design Factors (continued) The entire water quality treatment area should be planted appropriately for the soil conditions.Walled infiltration run-on Setbacks planters will be inundated periodically.Therefore the entire I Check with the local building department to confirm site-specific planter should be planted with herbaceous rushes,sedges, requirements. perennials,ferns and shrubs that are well-suited to wet-to-moist • For planters without an impermeable liner,generally the soil conditions. minimum setback from building structures is 10 feet. Because the entire facility will be inundated periodically,plant I .I Typically,no building setback is required for planters lined with the water quality treatment area with herbaceous species such waterproofed concrete or 60 mil.PVC liner to prevent infiltration. as rushes,sedges,perennials,ferns and shrubs appropriate for Soil Amendment/Mulch wet-to-moist soil conditions. Most moisture-tolerant plants can I Amended soils with appropriate compost and sand provide withstand seasonal droughts during the dry summer months and numerous benefits:infiltration;detention;retention;better do not need irrigation after they become established. plant establishment and growth;reduced summer irrigation Native plants are encouraged,but non-invasive ornamentals that I needs;reduced fertilizer need;increased physical/chemical/ add aesthetic and functional value are acceptable.All vegetation microbial pollution reduction;and,reduced erosion potential. should be planted densely and evenly to ensure proper hydrological Primary treatment will occur in the top 18 inch flow-through function of the flow-through planter. planter.Amended soil in the treatment area is composed of I organic compost,gravelly sand and topsoil. Compost is weed Quantities per 100 square feet: free,decomposed,non-woody plant material;animal waste is not •115 herbaceous plants,1'on center spacing,''/-gal container allowed.Check with the local jurisdiction or Clean Water Services size;or for Seal of Testing Approval Program(STA)Compost provider. •100 herbaceous plants,1'on center,and 4 shrubs,1gal iTo avoid erosion,use approved erosion control BMPs for flow container size 2'on center. through planters. I Vegetation Planted vegetation helps to attenuate stormwater flows and break down pollutants by interactions with bacteria,fungi,and other I organisms in the planter soil.Vegetation also traps sediments, 36 Low Impact Development Approaches Handbook cleanwate `Services I I Flow-Through Planter Page4of4 I ; - a � Il ,,,, ,,,,,„, ._ - 4 ,,,... ,.- ,,...„,, II lam+ { f ''''4\' ':''. , \� �1 � �0 4, I *: 4;2:::7: ‘.&„::'14zs,..:NZ.,.(4..:, : $ *-' 1 '-it 1%,..Sz-; ‘'''''-i-'4*-44C.$: ,-,--SZ, ''Z'-t4,,, .' -k' 4,`•‘ ' 44=. -4.1:* .«. 'k17-.- ' „„4"..fit "" IRose Quarter parking structure, NE Portland Washougal Town'.;;-:41,1i:;;;i*\ Square ma ,.,• :...--;;* 7 �'' f -,. t,t; -3 � } +,» '',#;„-4 3 A ark' . off t �e _ � VT3 x 3 lid }} t moo` ' 41314' � ze�� -.' - —,_.„. , \ , t 1... :::\\. Aloha Dog and Cat Clinic, Washington County , + / f ' f1 Buckman Terrace Apartments, Portland Required Maintenance Period References • Water efficient irrigation should be applied for the first two years Clean Water Services Design and Construction Standards after construction of the facility,particularly during the dry summer months,while plantings become established.Irrigation after these two years is at the discretion of the owner. • If public,the permittee is responsible for the maintenance of the flow through planter fora minimum of two years following construction and acceptance of the facility. Long Term Maintenance I If private,the property owner will be responsible for ongoing maintenance per apt recorded maintenance agreement(see page 88 for example maintenance agreement). For detailed Operation and Maintenance Plans that describe proper maintenance activities please refer to page 91. All publicly maintained facilities not located in the public I right-of-way must have a public easement to ensure access for maintenance. I cleanwater 'services Low Impact Development Approaches Handbook 37 MIN MI UN 11111 111111 all IIIIIN 11111111 MN =II SIM ill PIM 11111 Flow-Through Planter and Maintenance Plan Operation Annual inspections are required. it is recommended that the facility is inspected on a monthly basis to ensure proper function.The plan below describes inspection and maintenance activities, and may be used as an inspection log. Contact the design engineer, Clean Water Services or City representative for more information. Identified Problem Condition to Check for Maintenance Activity Maintenance Timing V Task Complete Comments Sediment Accumulation in Sediment depth exceeds 3 inches Remove sediment from treatment Treatment Area area Ensure planter is level from side to side and drains freely toward SUMMER FALL outlet;no standing water within 24 hours after any major storm (1-inch in Ideally in dry season 24 hours) 0rff Erosion Erosion or channelization that impacts Repair eroded areas and stabilized or effects the function of the facility or usingpmperemsinncnntm|mea' FALL WINTER SPRING creates asafety concern sures Establish appropriate vegetation rt) sneeded Inspect after major storm ro (1-inch in 24 hours) Standing Water Standing water in the planter between Remove sediment or trash blockages. tot storms that does not drain freely Grade out areas of mounding and - Water should drain after 34hours uf improve end toend grade sothere is dry weather. no stwater.andin� WINTER SPRING CIL �T. Flow Not Distributed Flow unevenly distributed through Level the spreader and clean so 0� Evenly planter width due to uneven or that flows spread evenly over entire clogged flow spreader planter width WINTER SPRING Obstructed Inlet/Outlet Material such as vegetation,sediment, Remove blockages from facility trash is blocking more than 10%of WINTER SPRING the inlet/outlet pipe Inspect after major storm co Flow-Through Planter Operation and Maintenance Plan ��=m�^���j�o~� ^ ^~^^ ' '^^ ~ cn^^ (continued) Annual inspections are required. It is recommended that the facility is inspected on a monthly basis to ensure proper function.The plan below describes inspection and maintenance activities, and may be used as an inspection log. Contact the design engineer, Clean Water Services or City representative for more information. Identified Problem Condition to Check for Maintenance Activity Maintenance Timing i/Task Complete Comments Poor Vegetation Coverage 80%survival of approved vegetation Determine cause of poor growth and and no bare areas large enough to correct the condition;replant with � facility.�����n� plugsormr�in��dc�/��ra� SPRING FALL * plants proved plans and applicable standards Ideal time to plant is springand at time of conruction.Remove ex- fall season cessive weeds and all invasive plants. rt Invasive Vegetation as Invasive vegetation found in facilityRemoveemce�siveweedsanda|| "' — r ��e outlined in Appendix Examplesindude�Hima|�mn Blackber- invasive plants.A�empttocontrn| �� '" ��r r�Reed[ana�G[a���Tease[ emenifcomp|etee�dicaboni�not SPRING SUMMER FALL English Ivy,Nightshade,Clematis, feasible.Refer to Clean Water Services Cattail,Thistle Integrated Pest Management Plan for appropriate control methods,includ- inging proper use of chemical treatment. Excessive Vegetation Vegetation gmwssota|| it competes Prunenvephanging limbs,if possible; with or shades approved emergent remove brushy vegetation as needed. SPRING wetland grass/shrubs;interferes with Prune emergent wetland grass/shrubs Ideal time to prune emergent access or becomes a fire danger that have become overgrown, wetland grass is spring Vector Control Evidence of rodents or water flowing Repair damage to facility. Remove As Needed through facility via rodent holes.Harm- harmful insects,call professional if ful insects such as wasps or hornets needed.Refer to Clean Water Services present Integrated Pest Management Plan for management options. INN NM EN EMI NM UN 1111 INN MIN OM IMO 11111 NM MI 1111 MEI 11111 VIE 11111 MN i IIIIII M MI M M VIII P IIIIII I MI E UM M M N v Flow-Through Planter Operation and Maintenance Plan (continued) Annual inspections are required. It recommended that the facility is inspected on a monthly basis to ensure proper function.The plan below describes inspection and maintenance activities, and may be used as an inspection log. Contact the design engineer, Clean Water Services or City representative for more information. ro Identified Problem Condition to Check for Maintenance Activity Maintenance Timing 6/Task Complete Comments Trash and Debris Visual evidence of trash,debris or Remove and dispose of trash and debris wo dumping. from facility. Dispose of properly SPRING SUMMER FALL WINTER Contamination and Evidence of oil,gasoline,contaminants, If contaminants or pollutants present, Pollution or other pollutants.Look for sheens, coordinate removal/cleanup with local odor or signs of contamination. jurisdiction. SPRING SUMMER FALL WINTER 3 r-. a Outlet Structure Damaged Grate or overflow structure is missing Repair or replace outlet structure. As Needed or only partially in place and may have missing or broken grate members. ro 0 ro tv 0- 0- 0 LSDLU I Infiltration Planter/Rain Garden Page lof4 Overflow drain Growing medium Structural wall parking areas &impermeable i landscape Inlet I .G A t f �e , , „txz, , t,1,,iii.,,,z..,„4,2:4:4; 1:z,,,,.'''''',\**,,:aii., , ,,,, 111111111 � '„ ,� 2 , , s.. permeable e freeboard � � �� jag k. soils t •6 \ � � �� € �- gala a sa *,,� ' � �a . ,'.-4'‘, y. � � `�� � � �• ��_ � �� a � vAv� I ' \\ tea,. \ \ .� ,�----' mac:` \ e .. ;\� Description Application & Limitations Infiltration Planters(also known.as rain gardens)are landscaped Infiltration planters should be integrated into the overall site reservoirs that collect,filter,and nfiltrate stormwater runoff, design and may help fulfill the landscaping area requirement. allowing pollutants to settle and filter out as the water percolates Infiltration planters can be used to manage stormwater flowing through planter soil and infiltrates into the ground.Infiltration from all types of impervious surfaces,from private property and planters typically require less piping than flow through planters within the public right-of-way.Check with the local jurisdiction if and a smaller facility size than traditional swales where native soils proposing to use infiltration planters in the public right of way. allow for infiltration. Depending on the site,infiltration planters The size,depth,and use of infiltration planters are determined by can vary in shape and construction,with or without walls to contain the infiltration rates of the site's existing soils. I the facility,or formed as a shallow,basin-like depression. 4ik--.' ° - s , Beaumont Village Lofts,NE Portland I 30 Low Impact Development Approaches Handbook C1eanWater Services I 1 Infiltration Planter/Ra ,, ;,_ 4 in Garden Page 2of4 , .. ,t, , ,,,,b,,, ., ,..,4,_.4 _ , ...t. ,, ,„,,, ,,. ,, , .,,,,,,,,,„',FZ,, ,.,.„(,,.‘' -,,f- - t4` .._ „ I 5'14 ' ? '4*-;::.‘,,,.: '''>;:4,1I':;\--N-s - Overflow drain s , , � 47 z, , , ' ,.4k. k - *4'4 '+ Growing medium �.;°_s Jute mattin I -4.-7%-t•-j=' , -. ''' '.t''''' i :,11i:,,,,,, z*:',i- -I:It—-..- '... 14'4'1•:,;„.:PrIA'lti.iti4.0::;iii:V, :!::::::'11:4: --''' � r , - --3-‘- 1 ,—t.g., ' -. C-; ‘,---::TA7r... ' „ + :.,, ,. . .4.,f,.It.—14 &14114144:-, ;-:'' a^ am~ '�l� ' �. d{sR� tI `s!'s �"^s.' r`�'� '':, ,,,.,.._4„;.,t,:,,,,,,,,41.7' .1-1 ,,,q,,,,,,,3/4.,uss, 17.44,:=4"46, ,,':./ 4,:jc,,,,'n'f4;;.7:1',.• F .: � �. ,�. u ' ';',-er.f.:7':-.1k. ' '.i.i.a ACi*.-.A"-- ,,,,t—;.t.''' ''`.*'-''''' 1—.., - .e0-4,.:1 :--:'.4*, w."-'.. .,„.--:-,--; ,,„-, ;--',t.----7,.::,. x a r---„[ .-.;,..t.--:.,,- -„.- '--ff ';`,.,..': fr.:, ,;,... .: - - '--7:7t1i-% -- ----:7-V 4'74-47' ''-. S.--::Vi;:` ,..e.TZ-t-rf-:-.''''' ',€,..-%:-- -..-:-'7--.:-:7-7:: .9i r.„,.it ,1,,,„..,.--.:77.,,e-fi,e-L.:, --„---- -:',..f..-,-,4-'Iiii;i;;;A:,;:,;',,i' ,,-, % i.e.,- , ,,,,':---;-Ar,%-1-„?.....- _r, - IDesign Factors Soil Suitability and Facility Sizing may flow directly from the public street right-of-way or adjacent The size and depth of the infiltration planter will depend upon the parking lot areas via curb openings. For infiltration planters with Iinfiltration rate of existing soils. A sizing factor of 0.06 assumes the walls,install an overflow drain to allow not more than 6 inches of site•infiltration rate is less than 2 in/hr. water to pond.Infiltration planters with side slopes,such as rain gardens,need an overflow drain to ensure no more than 6 inches For example,the size of an infiltration planter managing 1,500 of water will pond. On private property,follow Plumbing Code Isquare feet of total•impervious area would be 90 square feet(1,500 requirements for this overflow drain and piping,and direct excess x 0.06). stormwater to an approved disposal point as identified on permit drawings. Check with local jurisdiction or use Clean Water Services Size may be decreased if: Design and Construction Standards for additional information on I • Demonstrated infiltration rate is greater than 2 in/hr piping material for use in the public right-of-way. using ASTM D3395 09 method;or Setbacks • Amended soil depth is increased Check with the local building department to confirm site-specific I requirements, Geometry/Slopes • Generally,a minimum setback of 10 feet from building The shape maybe circular,square,rectangular,etc.to suit the structures is recommended. site design requirements.Regardless of the shape,9.minimum planter width of 30 inches is needed to achieve sufficent time for • Planters should not be located immediately upslope treatment and avoid short circuiting.Planters in a relatively flat of building structures. landscaped open area should not slope more than 0.5%in any Before site work begins,clearlymark infiltration )anter areas direction, 9 P II to avoid soil disturbance during construction,No vehicular traffic Piping for Infiltration Planters should be allowed within 10 feet of infiltration planter areas, Follow Plumbing Code requiremeI nts for piping that directs Istormwater from impervious surfaces to planters.Stormwater C1eanWater Services Law. Impact Development Approaches Handbook 31 I Infiltration Planter/Rain Garden Page3of4 I « ; � ■ `,'F',04-, ,--�, 1 ' - . i 411"I **A., , ,,,, - -. ,,z.si k - ----- 4,:, .r:,0" L.1, --. oit I 1.).. .'‘,,:5". chi .11 . . \ °' - :„:.•' \''''.---,..--,.-:' ..,rz «. ,L '`` ��C� t em'. ,a y �w ,.., ,,,,,, „4„..,„,,,,,:,,,,.,_ -,..,,,,,, - ,,,,,,,4' •-•-•,,,,.!,,.. .„1.,� New Seasons,20th and SE Division St.,Portland ,, . �. a - should be planted with herbaceous rushes,sedges,perennials, I ferns and shrubs that are well-suited to wet-to-moist soil ..4 c : conditions. If the infiltration planter has side slopes(basin without vertical Buckman Terrace Apartments,Portland walls),soil conditions will vary from wet to relatively dry;several planting zones should be considered.The flat bottom area will Design Factors (continued) be moist-to-wet,and the side slopes will vary from moist at the bottom to relatively dry near the top where inundation rarely except as necessary to construct the facility.Consider construction of occurs.The moisture gradient will depend upon the designed infiltration planter areas before construction of other impervious maximum water depth,total depth of the planter,and steepness I surfaces to avoid unnecessary traffic loads. of the side slopes.This moisture gradient is a transition zone and should be planted with species that tolerate occasional standing Soil Amendment/Mulch water,and plants that prefer drier conditions toward the top of Amended soils with appropriate compost and sand provide the slope.Areas above the side slopes,immediately adjacent numerous benefits:infiltration;detention;retention;better to the basin,and above the designed high water line will not plant establishment and growth;reduced summer irrigation be inundated and should be planted with self-sustaining,low needs; reduced fertilizer need;increased physical/chemical/ maintenance grasses,perennials,and shrubs suitable for the local microbial pollution reduction;and,reduced erosion potential. climate. Primary treatment will occur in the top 18 inches of the infiltration planter.Amended soil in the treatment area is composed of Native plants are encouraged,but non-invasive ornamentals organic compost,gravelly sand and topsoil. Compost is weed- that add aesthetic and functional value are acceptable.All I free,decomposed,non-woody plant material;animal waste is not vegetation should be planted densely and evenly to ensure proper allowed.Check with the local jurisdiction or Clean Water Services hydrological function of the infiltration planter. for Seal of Testing Approval Program(STA)Compost provider. Quantities per 100 square feet: To avoid erosion,use approved erosion control BMPs for non- •115 herbaceous plants,1'on center spacing,/-gal container structural infiltration planters. size;or Vegetation •100 herbaceous plants,l'on center,and 4 shrubs,1-gal I Planted vegetation helps to attenuate stormwater flows and break container size 2'on center. down pollutants by interactions with bacteria,fungi,and other organisms in the planter soil.Vegetation also traps sediments, Trees are optional;if used,minimum 2 gallon by 2 feet tall. I reduces erosion,and limits the spread of weeds.Appropriate, carefully selected plantings enhance the aesthetic and habitat Trees are allowed in infiltration planters and should be selected value.For a complete list of allowable plants refer to see page 76. by their adaptability to wet-to-moist conditions and full size at maturity.An area twice the width of tree rootball and the depth of The entire water quality treatment area should be planted the rootball plus 12"(or total depth of 30",whichever is greater) appropriately for the soil conditions.Walled infiltration run-on should be backfilled with amended soil for optimal growth,with planters will be inundated periodically.Therefore the entire planter no sub-surface rock layer.For infiltration planters with side slopes, I trees should be placed along the side slopes of the facility rather than at the bottom. I { 32 Low Impact Development Approaches HandbookC1eanWater'Services I ..,, , „u‘s.,,,, ' " : '*:,;..".44:.4-1:-:#7.-::*--.--..,. 1-- .,,;:iI 1 Infiltration - - . 4,-., .; . 42' .;'' ?:::,° ...or.--:' 4'.' Planter ..;.., ,,,„ ,....„:„..,,, i. . .,7::4.-;,i4,..c.,.,. .„.„.,,, -, /Rain Garden Page4of4 ..,..„,,, . , ,... ., ;„- - ...„ ..- - -,-.,,4. I „-, , ,,,,.. .,,,,,,, ,-.,- ,,- -, --...., . ,-...„.*t. ..,,,,, ,,,,,:. „..-.'1 .,++,44 J -,..,+ A ', _ , , , ,., te- e'e '`.c- .-�, _ `. �� x yam,..; „, 4."11,- ...--- � ���� •� '� , ��� 1”‘„+ 5 ' ... - ,rte „..,..;,` '' „,„ , 4.,:`,"* A ,, ,,k ...,,, � A � c`f ` -„, „-, , .„ 3 r „, ...,...4.,.,,,N..'•_,.,Iirw. I . � � v� R= . I Mississippi Commons,NE Portland Fowler Middle School, Tigard Required Maintenance Period3....,e-•.`'. .: ria:,1,-,4,,,,, ;• ,i,--,T,,, ,,,,, ,. .. ..,-*:-,,, • Water efficient irrigation should be applied for the first two ears �� ' aI fter construction of the facility,particularly during the dry y � � ' i..,.....,,,....,, ,..,,,,,,-- -.. summer months,while plantings become established.Irrigation z r.7.7„-.404- , � I after these two years is at the discretion of the owner. AP''' • If public,the permittee is responsible for the maintenance of the infiltration planter for a minimum of two years following construction and acceptance of the facility. I Long Term Maintenance � I If private,the property owner will be responsible for ongoing Q'”' �=�A maintenance per a recorded maintenance agreement(see page 88 for example maintenance agreement). 12th and Montgomery St., Portland I For detailed Operation and Maintenance Plans that describe proper maintenance activities please refer to page 91. IAll publicly maintained facilities not located in the public right of way must have a public easement to ensure access for maintenance. References Clean Water Services Design and Construction Standards 1 I _i cteanwa Services Low Impact Development Approaches Handbook 33 4- Infiltration Planter / Rain Garden Operation and Maintenance Plan Annual inspections are required. It is recommended that the facility is inspected on a monthly basis to ensure proper function.The plan below describes inspection and maintenance activities, and may be used as an inspection log. Contact the design engineer, Clean Water Services or City representative for more information. Identified Problem Condition to Check for Maintenance Activity Maintenance Timing V Task Complete Comments Invasive Vegetation as Invasive vegetation found in facility. Remove excessive weeds and all outlined in Appendix A Examples include:Himalayan Blackberry; invasive plants.Attempt to control Reed Canary Grass;Teasel; English Ivy; even if complete eradication is not Nightshade;Clematis;Cattail;Thistle; feasible.Refer to Clean Water Services Scotch Broom Integrated Pest Management Plan for SPRING SUMMER FALL appropriate control methods,including Q7) proper use of chemical treatment. ro rn -6- 3 Obstructed Inlet/Outlet Material such as vegetation,trash, Remove blockages from facility sediment is blocking more than 10% of the inlet pipe or basin opening WINTER SPRING 7:3 Inspect after major storm (-1 (1-inch in 24 hours) rD LI Excessive Vegetation Vegetation grows so tall it competes Cut tall grass 4"to 6"and remove CT with or shades approved emergent clippings.Prune emergent wetland 0 wetland grass/shrubs; interferes with grass/shrubs that have become SPRING access or becomes a fire danger overgrown. Ideal time to prune emergent wetland grass is spring.Cut grass during dry months Tree/Shrub Growth Tree/shrub growth shades out Prune trees and shrubs that block sun wetland/emergent grass in treatment from reaching treatment area.Remove area. Interferes with access for trees that block access points. WINTER maintenance/inspection Do not remove trees that are not interfering with access or maintenance Ideal timing for pruning trees is without first contacting Clean Water winter .74 Services or local City. WIN IIIIII ale Ell MIN Mil NIB nil IMO IIIIIII MIN IIIIII 11111 NMI MIN NMI MI1 11111 11111 NS r all 1 NS M — s NM 1 i V N - - - - r w Infiltration Planter / Rain Garden Operation and Maintenance Plan (continued) Annual inspections are required. It is recommended that the facility is inspected on a monthly basis to ensure proper function.The plan below describes ti inspection and maintenance activities, and may be used as an inspection log. Contact the design engineer, Clean Water Services or City representative for more information. Identified Problem Condition to Check for Maintenance Activity Maintenance Timing V Task Complete Comments Hazard Trees Observe dead,dying or diseased trees Remove hazard trees. A certified As Needed arborist may need to determine health of tree or removal requirements Poor Vegetation Coverage 80% survival of approved vegetation Determine cause of poor growth and 0 and no bare areas large enough to correct the condition.Replant per the affect function of facility. approved planting plan and applicable SPRING FALL standards at the time of construction. Ideal time to plant is spring and Remove excessive weeds and all fall seasons rD invasive plants. rD0 rDTrash and Debris Visual evidence of trash,debris or Remove trash and debris from facility. dumping Dispose of properly �:F '� SPRING SUMMER FALL WINTER 0 9J Contaminants and Pollu- Evidence of oil,gasoline,contaminants If contaminants or pollutants are tion ; or other pollutants.Look for sheens, present,coordinate removal/cleanup odor or signs of contamination. with local jurisdiction SPRING SUMMER FALL WINTER 0 Erosion Erosion or channelization that impacts Repair eroded areas and stabilize using or effects the function of the facility or proper erosion control measures. creates a safety concern Establish appropriate vegetation as needed. FALL WINTER SPRING Flow Not Distributed Flows unevenly distributed through Level the spreader and clean so Evenly planter width due to uneven or that flows spread evenly over entire ; , clogged flow spreader planter width WINTER SPRING Cid _n cy, Infiltration Planter / Rain Garden Operation and Maintenance Plan (continued) Annual inspections are required. It is recommended that the facility is inspected on a monthly basis to ensure proper function.The plan below describes inspection and maintenance activities, and may be used as an inspection log. Contact the design engineer, Clean Water Services or City representative for more information. Identified Problem Condition to Check for Maintenance Activity Maintenance Timing V Task Complete Comments Vector Control Evidence of rodents or water piping Repair facility if damaged.Remove As Needed through facility via rodent holes. harmful insects,use professional if Insects such as wasps and hornets needed.Refer to Clean Water Services interfere with maintenance/inspection Integrated Pest Management Plan for activities management options rD Sediment Accumulation in Sediment depth in treatment area Remove sediment from treatment -0 Treatment Area exceeds 3 inches area.Ensure planter is level from , f CD side to side and drains freely toward SUMMER FALL outlet;no standing water within 24 -0 hours after any major storm(1-inch Ideally in the dry season in 24 hours) ro 0.) Standing Water Standing water in the planter Remove sediment or trash blockages; ca_ between storms that does not drain improve end to end grade so there is freely.Water should drain after 24 no standing water 24 hours after any WINTER SPRING c•'" hours of dry weather major storm(1-inch in 24 hours) Inspect after major storm (1-inch in 24 hours) Grate Damaged, Missing Grate is missing or only partially in Grate must be in place and meets As Needed or Not in Place place may have missing or broken design standards. Replace or repair grate members any open structure I CA F). CD, all all 111111 11111 NIB Ell 111111 all NM NM MN NM EN EN NMI 11111 I i Vegetated Filter Strip Page 1 of 3 IAdjacent impermeable surface Evenly distributed sheet flow of Gravel trench&level set grade stormwater through vegetation �_ board(if required) parking areas Jute matting &impermeable I i?d ._ landscape Iiis Check dam or berm every 10'for slopes greater than 20H:1V IT). impermeable s t a \ soils 4.= 1 ".' -8, . 1 t ,kj, *.� t awl r A d ,,,,,..*:‘,..4.-&',8„,..z . i°` �a )311,�: �' IIIIIIIIIIIIIIIIII I '.� N t . . �a :- permeable a , i 4. soils 7 k ,� .� {4 1 .\' ,.1c.4- �, � .a_ --„''..q-.,-'„.•. '� ..s �� '� '..\,J.\\�\ �'� -'-%.,„.,,,_k,-1,....-N,,,. . \,- ,, � .\£����... DescriptI ion Application & Limitations I Vegetated filter strips are gently sloped areas designed to receive Vegetated filter strips should be integrated into the overall site sheet flows from adjacent impervious surfaces.Filter strips are design and may help fulfill a site's landscaping area requirement. vegetated with grasses and groundcovers that filter and reduce the Vegetated filter strips can be used to manage stormwater runoff I velocity of stormwater.Peak stormwater flows are attenuated as from aa variety of impervious surfaces such as walkways and stormwater travels across the filter strip and infiltrates or is stored driveways on private property and within the public right-of-way. temporarily in the soils below. Check with the local jurisdiction if proposing to use a vegetated filter strip in the public right of way. I For residential driveways,center filter strips typically are 3 feet wide between two 3-foot wide paved sections.The strip treats and infiltrates stormwater only from the impervious area of the drive aisles which slope toward the center filter strip.The driveway center e � � a „ fI ilter strip must be maintained to the design requirements for ;ik vegetated filter strips. _ , til I A. @ ?t4414 \pi V%4.,,*,','44 44-k '1 ty47,4:4 r*,) ,,-, f i.# S Niv, Ore on Zoo arkin lot Por l n 9 P 5 to d I 42 Low Impact Development Approaches Handbook cleanwater� services 1 Vegetated Filter Strip , , Page2of3 ",. � °'' >t r:TM arm � :.. ,.. '' { *,, , � , ,, - -vii.,.''4 ,Q,„ VI.,.1s ':l'A*‘, ' tket. .' *''. g 'Is. '� - ° � ? - r ,.� � sai" :,k B ` _ aad � 'A i '4� fes? �. r ,ice m`�[ r_. it � =; �� € r ,E is a �` ,�� a „a + c . € T s w F° y ' :1114.:;" V 4%,47.4 K,,„,` ' .. .cog¢`« - , - - ' , ft.•. f,* .;,, ,..'' ;,,,.„0:4,.....,,-;41. ...'. 7, YA. ,,,,, ;-... imiimim z � I IIIt 4:'1 ,t1IS:,,,,,, es4 .-. (4,14:, ,,, , ,:k•,,,i4e..„.„- -. j',."."4- -: ",.:.: *. .1*--% . -, iiiiiii iiiiiiiii z-, ii ii"-- i i li,,0 i...,,,kit'4'0 ti"N 4,1",,,,,,,,ebl''<„,.,.N.."„-i;.,:f ITsrflik,'..1,,,.:1.1.41,,,, II-1)14 4,` '' .... . , I ir � .c y n§ Design Factors Oregon Zoo parking lot Sizing Piping for Vegetated Filter Strips Vegetated filter strips are appropriate for all soil types and have Non infiltrated flows/overflows from the vegetated filter strip are 18"depth of growing medium. The size of the filter strip will collected and conveyed to an approved system or outlet structure. 111 depend upon the infiltration rate of existing soils. A sizing factor of 0.06 assumes that the site has an infiltration rate less than 2 in/hr. Setbacks Check with local building department to confirm site-specific For example,a facility managing 1,500 square feet of total requirements. impervious area would require a 90 sq ft filter strip(1,500 x 0.06). Soil Amendment/Mulch Size may be decreased if: Amended soils with appropriate compost and sand provide • Demonstrated infiltration rate is greater than 2 in/hr numerous benefits: infiltration;detention; retention;better plant using ASTM D3395 09 method;or establishment and growth;reduced summer irrigation needs; • Amended soil depth is increased reduced fertilizer need;increased physical/chemical/microbial pollution reduction;and,reduced erosion potential.Primary Geometry/Slopes treatment will occur in the top 18 inches of the vegetated filter The minimum width of a vegetated filter strip is 5 feet measured in strip.Amended soil in the treatment area is composed of organic the direction of stormwater flow.The slope is between 0.5 and 6%, compost,gravelly sand and topsoil. Compost is weed free, and the slope of the impervious area draining to the strip is less decomposed,non woody plant material;animal waste isnot than 6%. allowed.Check with the local jurisdiction or Clean Water Services Check dams may be required to maintain shallow slopes if the for Seal of Testing Approval Program(STA)Compost provider. I existing site slopes exceed 5%. Typically,check dams are 3 to 5° To avoid erosion,use app roved erosion control BMPs for vegetated inches high and are placed every 10 feet where slopes exceed 5/o. g If a level spreader such as a grade board orsand/gravel trench is filter strip. required to disperse runoff evenly across the filter strip,the top I must be horizontal and at an appropriate height to direct sheet flow to the soil without scour.Grade boards may be any material that withstands weather and solar degradation but should not be I old railroad ties,used utility poles,or other pollutant source° cleanwater 'Services Low impact Development Approaches Handbook 43 I 4 I 1 Vegetated Filter Strip Page 3 of 3 .. . ,, \ \ _ „ A �� ..i.,;,. a . - s t, \ � 4 \ ...k , :,-, 4, Al.. { , j \ 4, # 1 F � � �� � j` , 4 �� a '' * ,, ,..e , -I-4 4,4 4 ,,-,44- IT-,„kysi, 404- 34z,1'V'kV. ,,„> ). 4,,,,4,,,,\; -?,-,- : , *, ,,,,k‘,., ,..,...-,,,,..-,,,, .-,,,i...-0, -,,, -:- Arata Creek School, Troutdale I Design Factors (continued) Required Maintenance Period I Vegetation • Water-efficient irrigation should be applied for the first two years Herbs,shrubs and grasses can provide the vegetation needed after construction of the facility,particularly during the dry to remove sediment and pollutants. The vegetated filter strip summer months,while plantings become established.Irrigation IS planted or seeded with a mix of grasses,wildflowers,and after these two years is at the discretion of the owner. groundcovers well suited to moist-to-dry soil conditions. All • If public,the permittee is responsible for the maintenance of vegetation should be self-sustaining and drought tolerant. the vegetated filter strip for a minimum of two years following construction and acceptance of the facility. I Native plants are encouraged,but non-invasive ornamentals that add aesthetic and functional value are acceptable.For a complete LongTerm Maintenance list of allowable plants refer to page 76. l If private,the property owner will be responsible for ongoing Trees are not required for vegetated filter strips,but are encouraged maintenance per a recorded maintenance agreement(see page 88 where applicable. Tree species should be selected by their for example maintenance agreement). adaptability to moist-to-dry conditions and full size at maturity. The filter strip conveys evenly-distributed sheet flows of water For Detailed Operation and Maintenance Plans Refer to page 91 for II through vegetation for treatment.Because unplanted areas may maintenance. decrease stormwater treatment,the entire filter strip must have 100%vegetation coverage to ensure proper hydrologic function. All publicly maintained facilities not located in the public I right-of-way must have a public easement to ensure access for If check dams are required,plants suited to wet to moist planting maintenance. conditions may be supplemented on the upslope side of the check dam where occasional inundation and pooling of water may occur. References IClean Water Services Design and Construction Standards I I I 44 Low Impact Development Approaches Handbook cleanwaterServices Vegetated Filter Strip Operation and Maintenance Plan Annual inspections are required. It is recommended that the facility is inspected on a monthly basis to ensure proper function.The plan below describes IV inspection and maintenance activities, and may be used as an inspection log. Contact the design engineer, Clean Water Services or City representative for more information. Identified Problem Condition to Check for Maintenance Activity Maintenance Timing V Task Complete Comments Flow not distributed evenly Flows unevenly distributed through Level and clean the spreader so that filter strip due to uneven or clogged flows spread evenly over entire filter " „;` flow spreader strip width WINTER SPRING Invasive Vegetation as Invasive vegetation is found in facility. Remove excessive weeds and all m rT outlined in Appendix A Examples include:Himalayan Blackberry; invasive plants.Attempt to control Reed Canary Grass;Teasel; even if complete eradication is not SPRING SUMMER FALL English Ivy;Nightshade;Clematis; feasible.Refer to Clean Water Services Cattail Thistle;Scotch Broom Integrated Pest Management Plan for appropriate control methods,including proper use of chemical treatment. CDPoor Vegetation Coverage 80% survival of approved vegetation Determine cause of poor growth 4 ro and no bare areas large enough to and correct the condition;replant 4/ --4r affect function of facility, with plugs or containerized plants FALL SPRING per approved plans and applicable o standards at time of construction. Ideal time to plant is Spring and Remove excessive weeds and all Fall seasons CC) invasive plants 0_ Excessive Vegetation Vegetation grows so tall it competes Cut grass tall grass 4” to 6"and with or shades approved emergent remove clippings. Prune emergent SPRING wetland grass/shrubs;interferes with wetland grass/shrubs that have Ideal time to prune emergent access or becomes a fire danger become overgrown. wetland grass is Spring.Cut grass in dry months Tree/Shrub Growth Tree/shrub growth shades out Prune trees and shrubs that block sun wetland/emergent grass in treatment from reaching treatment area.Remove area.Interferes with access for trees that block access points. WINTER maintenance/inspection Do not remove trees that are not Ideal timing for pruning trees is interfering with access or maintenance winter without first contacting Clean Water Services or local City. M M MO M E I 1111111 E - - all M r g M M — M r OM NIS 11111 Ell Ell EN 11111 EN IMO MIN Ell MO 11111 11111 MN MB EN NIS c'— Vegetated Filter Strip Operation and Maintenance Plan (continued) Annual inspections are required. It is recommended that the facility is inspected on a monthly basis to ensure proper function.The plan below describes inspection and maintenance activities, and may be used as an inspection log. Contact the design engineer, Clean Water Services or City representative for more information. Identified Problem Condition to Check for Maintenance Activity Maintenance Timing V Task Complete Comments Erosion Erosion or channelization that impacts Repair eroded areas and stabilize using or effecthe functioof the facility or proper erosion control measures too,� � creates a safety concern Establish appropriate vegetation as WINTER SPRING needed Sediment Accumu|adonin Sediment depth intreatment aeu Remove sediment fmmt�atment Treatment Area exceeds 3 inches area. CD Ensurefacility is level from ` 4, ~ side to side and drains freely toward SUMMER FALL riP outlet;no standing waer once inflow Ideally in the dry season has ceased Trash and Debris Visual evidence of trash,debris or Remove trash and debris from facility. rD dumping Dispose of properly SPRING SUMMER FALL WINTER cr 74— Contaminants and Evidence of oil,gasoline,contaminants If contaminants or pollutants present; ^ ^~ ' Pollution or other pollutants. Look for sheens, coordinate removal/cleanup with local „m odor or signs of contamination jurisdiction SPRING SUMMER FALL WINTER Vector Control Evidence of rodents or water piping Repair facility if damaged.Remove As Needed through facility via rodent holes. harmful insects,use professional Harmful insects present such as wasps service if needed. and hornets that interfere with mainte- Refer to Clean Water Services nance/inspection activities Integrated Pest Management Plan for management options 0O 0. 0 :///9:,'/I: tn ') N n IC 0 M ,, > A/ MD 0,, 4 ____ = rim! :, ,,,, _ i c=,_ ///, // , rDo , , ,,„. /7O , 73 t. MO MN EN NM MN EN MN r N MN N EN NM EN EN NM General Inspection and maintenance of the StormCapture system is vital for the satisfactory performance and life cycle Iof the stormwater management system. Permit requirements, local, state and federal regulations, along with Oldcastle and any incorporated device manufacturer recommendations must be followed for system compliance. The StormCapture design provides manway access for ease of inspection and debris removal if required. Flushing, Iwhich can cause particle displacement, undermining and internal disturbance, is not recommended for gravel foundation, open bottom systems. Flushing is acceptable in systems with concrete bases. Inlet controls, internal or external, are recommended for controlling, monitoring and maintaining the StormCapture system. IExternal Inlets are typically devices that are separate from the StormCapture modules. These external devices receive site stormwater and are designed with manway access for maintenance and typically include an internal Isump for sediment capture. External inlets may receive single or multiple pipes and incorporate an open grated top with an outfall pipe to the StormCapture system. Grated inlets may incorporate protection devices or baffles to capture floatables or the "first flush". Scheduled inspections and maintenance shall include the removal of any Isedimentation build up in the external inlets. Debris or sedimentation build up shall not exceed 3" below an outfall elevation. Internal components may be incorporated for pre-treatment. Manufacturer recommendations must be followed. Scheduled maintenance and inspection will include removal of debris and sediments by manual or mechanical means. Maintenance Modules (MM's) are optional internal control modules based on design preference. MM's are Imodules with roof manway access openings and provide the primary means of access to the StormCapture system for scheduled inspection and maintenance. In addition, MM's may incorporate weirs or baffles to enhance reduction or removal of Total Suspended Solids (TSS) from the stormwater. Placement of internal components Imust be part of the system engineering and design. Grated inlets can be incorporated to accommodate surface stormwater flows into the StormCapture and may include an inlet protection device. Schedule inspection and manufacturer recommendations for maintenance must be followed. IFor open bottom systems (no concrete floor), concrete splash pads may be installed below inlet grate openings and pipe inlets to prevent base erosion. During scheduled inspection and maintenance activities, the concrete splash pads must be inspected for proper function and any sediment shall be removed. Standard StormCapture Imodule design incorporates lateral and longitudinal passageways between modules to accommodate internal stormwater conveyance between modules. These passageways may be of a window configuration with standard 12" tall sediment baffles below the windows extending from the internal module invert, or doorway configurations extending from the floor slab. Any sediment and debris build up over 6" deep inside a module shall be removed by manual or mechanical means. Removal by vacuum is recommended. Internal module flushing, which can cause particle displacement, undermining or internal disturbance, is prohibited. ' Inspection Frequency p q Y ' Oldcastle recommends that the StormCapture system be inspected quarterly, and following any significant rain events within the first year of operation. Standard Operating Procedures shall specify an annual inspection and maintenance plan as required thereafter or as stated in the permit, or as required by other governing regulations. IOnly authorized and trained personnel shall inspect and enter a StormCapture system. Personnel must be properly trained and equipped before entering any underground or confined space structure. Training includes being familiar with and following any local, state and federal regulations governing the operation, inspection and maintenance of underground structures, as well as specific StormCapture system requirements. 1 I Inspection Activities During inspection, a minimum of the following shall be inspected: I • Contributing drainage area inlets are clear of debris. • If the StormCapture system is an exfiltration system (open bottom with stormwater percolating into the I ground), monitor and confirm that the system drains completely within a reasonable time or the required permit time. • Sediment depths within modules (anything over 6" deep shall be removed as outlined above). I • Inlet and outlet pipe penetrations to check for movement and/or leakage. • Movement of modules. I • General interior condition of modules to look for concrete cracking or deterioration. • Condition of pre-treatment devices, baffles and polishing devices if part of the system. I Recordkeeping A log must be kept of all inspection and maintenance activities. I I 1 I I I 1 I I I I 3 I - - 1 ® 1 1 OUR MARKETS 1 BUILDING COMMUNICATIONS ENERGY TRANSPORTATION STRUCTURES WATER i 1 1 i 1 1 www.oldcastlestormwater.com OldCastle Precast® 800-579-8819 Stormwater Closed Detention System (TankNault) Operation and Maintenance Plan Annual inspections are required.The plan below describes maintenance and inspection activities and may be used as an inspection log. Contact the design engineer, Clean Water Services or City representative for more information. Identified Problem Condition to Check for Maintenance Activity Inspection Frequency ✓ Task Complete Comments ce Trash and Debris Visual evidence of trash,debris or Remove trash and debris from facility. Monthly and after any major r dumping Dispose of properly storm 0-inch in 24 hours) Annually Required °' Debris and Sediment in Depth of accumulated sediment Remove sediment and debris from Annually Required or as , Storage Area exceeds 10%of the storage area storage area. Dispose of properly needed diameter for'' length of storage vault, or exceeds by 15%of diameter at any point(Example:72-inch storage tank ee v to be cleaned if sediment is 7 inches deep for more than Y2 length of tank) re 0 Plugged or Damaged Air Vent is damaged or'ft of vent cross Clear vents openings.Repair if damaged Monthly from November ee 5 Vents in Storage Area section is blocked and ensure they are functioning through April Lre ee properly Annually Required 3 Open Joints Between Tank/ Openings or voids between tank/' All joint between tank/pipe sections Annually Required rD Pipe Section within Storage pipe section that allows material into are sealed.Requires engineering o Area facility analysis to determine structural ce stability re Tank/Pipe Bent Out of Any part of tankipipe is bent more Replace or repair tankipipe to design Annually Required Shape within Storage Area than 10%of its design shape standards. May require engineering analysis to determine structural stability Vault Structure Damaged. Cracks wider than 112 -inch and any Vault replaced or repaired to design Annually Required re e Cracks in Walt Bottom, evidence of soil entering the structure. specifications.May require engineering Damage to Frame and/or Inspection determines the vault is not analysis to determine structural Top Slab. structurally sound stability cA N _ .. l ME iiii 11111 N OM MI N M NE I NM MI NE M NM 111111 MII EN 1111 11111 111111 11111 11111 NB Mil INN EN MIN 1111111 INN 1111111 111111 EN NM NE 111111 Closed Detention System (Tank/Vault) Operation and Maintenance Plan (continued) Annual inspections are required.The plan below describes maintenance and inspection activities and may be used as an inspection log. Contact the P4 design engineer, Clean Water Services or City representative for more information. Identified Problem Condition to Check for Maintenance Activity Inspection Frequency V Task Complete Comments Cracks at joints of inlet/ Cracks wider than Y2 -inch at the joint Repair cracks if possib:e.If cracks Annually Required oudet pipes or walls of inlet/outlet pipe or any evidence wider than 1/2-inch at inlet/outlet pipe of soil entering the vault through the joints,seal joints or replace pipe as walls needed. ro Locking Mechanism Not Mechanism cannot be opened by one Repair mechanism to allow access Annually Required Working at Manhole maintenance person with proper tools; .c) bolts into frame have less than 'h inch of thread(may not apply to self-locking lids), fl n. Manhole Cover lc in Cover is missing or only partially Replace or reinstall rnarino,e cove,to Annual y Required Place in place;any open manhole needs ensure it is closed maintenance. CD 2 ro Lauder Rungs in Manhole Maintenance person determines ladder Ladder must be repaired or secured Annually Required --0 Unsafe is unsafe(missing rungs, misalignment, immediately.Ladder meets design rust,cracks); standards and allows safe access for maintenance CD 5 0 co � Appendix GPlan Sheets 1 Otak