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Home My WebLink About20073263.tiff • • • • � • CHANGE OF ZONE DRAINAGE REPORT • • WATERFRONT AT FOSTER LAKE • • WELD COUNTY, COLORADO • • • Prepared for: • • HF HOLDINGS C/O DARWIN HORAN • ATTN: LINDA SWEETMAN-KING • 4 Inverness Court East#300 • Englewood, CO 80112 • • Prepared by: TETRA TECH 1900 S. Sunset Street, Suite 1-F • Longmont, Colorado 80501 • • • Tetra Tech Job No. 80-5161.002.04 • • • July 2007 • • • [ThJ TETRA TECH • , • 2007-3263 • 9 TETRA TECH • July 3, 2007 Mr. David Bauer, P.E. Senior Engineer . Weld County—Public Works 1111 H Street Greeley, CO 80632 . Re: Change of Zone Drainage Report for Waterfront at Foster Lake, Weld County, Colorado Tetra Tech Job No. 80-5161.002.04 Dear Mr. Bauer: Tetra Tech,on behalf of Terravisions, is submitting this Change of Zone Drainage Report for Waterfront at Foster Lake. This report provides information regarding historic and developed drainage patterns, as well as the on site permanent water quality measures. This drainage report corresponds to the change of zone plans contained with this submittal. . • If there are any questions or comments, or if you would like additional information concerning this report, please feel free to contact us. Sincerely, TETRA TECH, • Aaron tines, E.I.T. . Design Engineer Reviewed By: Cameron Fowlkes, P.E. Project Manager • Attachment R:\5161_002_anderson\Documents\5161_002_04\drainage\report\Chan geOfzuneDrai n ageReport(062807).doc ▪ • S 9 S utSwic I c ;'no�!.OO(3)501 5 Tel. nl Fax -r,� ,. ...✓:cl k ' wn- TETRA TECH ENGINEER'S CERTIFICATION • • "I hereby certify that this report for the preliminary drainage design of Waterfront at Foster Lake • was prepared under my direct supervision in accordance with the provisions of the Weld County • storm drainage criteria for the owners thereof." • ameron i•s es, P.E. ,/ • s Registered : Qe9sjg wl 'cc"- er • State of Colo '. c,t k11E • • •• • 9 ▪ • TABLE OF CONTENTS • Page 1.0 General Location and Description 1 2.0 Drainage Basins and Sub-Basins 2 3.0 Drainage Design Criteria 3 4.0 Drainage Facility Design 3 5.0 Conclusions 6 6.0 References 7 APPENDICES References A Historic Drainage Calculations B ▪ • Detention Pond Sizing Calculations C Developed Drainage Calculations D Water Quality Measures E DRAWINGS . Historic Drainage Plan Back Pocket Developed Drainage Overall Plan Back Pocket . Sub Basin Drainage Map Back Pocket Erosion Control Plan Back Pocket ▪ • H - 9 • CHANGE OF ZONE DRAINAGE REPORT WATERFRONT AT FOSTER LAKE • WELD COUNTY, COLORADO 1.0 GENERAL LOCATION AND DESCRIPTION Intent The purpose of this report is to provide a conceptual drainage design for Waterfront at Foster . Lake. This drainage report provides the calculations for the historic and developed runoff, and the design of the proposed detention ponds. Street capacity calculations, pipe sizing, and inlet sizing will be submitted with the Final Drainage Report. Information regarding offsite roads, nearby schools and adjacent land parcels has been included in this report. Location Waterfront at Foster Lake is approximately a 587 acre subdivision located in the South Half of . Section 27 and the North Half of Section 34, Township 3 North, Range 68 West and the . Northeast Quarter of Section 3, Township 2 North, Range 68 West of the 6th Principal Meridian, county of Weld, state of Colorado. More specifically, the property is bordered on the east by I- 25, on the west by Weld County Road (WCR) 7, on the south by the St. Vrain State Recreation area and the St. Vrain River, and on the north by Foster Reservoir and agricultural land. (Refer to Appendix A for Vicinity Map.) The 5 acre property owned by James Anderson and located at I 3528 Weld County Road 28 is not included with this project development. This property will be identified on the drainage plans. Description of Property The property encompasses the majority of the land surrounding Foster Reservoir. Weld County Road (WCR) 28 bisects the northern portion of the project, and WCR 7 abuts a portion of the . western property boundary. Five single family residences with outbuildings exist on the site. The Anderson Farm headquarters is located at 3528 WCR 28. This 5 acre piece of property is not part of this development. This area contains one single family residence, a garage, a truck scale, a shop, two barns, and a cattle feedlot. An equipment storage area and silage pits are north of WCR 28. The southern portion of the property contains an abandoned home and a storage . building. The remainder of the property was developed for agricultural production. Fields were . alternately cultivated with hay, or were lying fallow. Fallow fields were most recently used to grow corn. One main, and several localized irrigation ditches occur on the property, as well as six natural gas production facilities. The irrigation ditches include the Hay Seed Ditch and the Highland Ditch, along with various tailwater ditches. The Hay Seed Ditch is an existing ditch that carries pumped water from the St. Vrain River to existing storage ponds at the south end of the property. This water will be used for a non-potable irrigation system for the proposed development. This Highland Ditch will be piped near its . current alignment until our Eastern Property Boundary. ID • • 1- I . • The proposed development on the site will consist of approximately 1800 residential units with a . small amount of commercial property. The project is currently surrounded by agricultural land and is located north of the St. Vrain River and south of Foster Reservoir. Due to the size of the development, it is proposed that the subdivision will be constructed in . multiple phases. The number of phases and what each would entail has not been determined as of yet, but it is likely that some phases will be built concurrently. Elevations on this site range from 4820 to 4985. Topography is variable, ranging from gentle in . the northern portion of the property, to moderate near the St. Vrain River. Geology includes . alluvial sands and gravels deposited by the St. Vrain River in the southern portion of the site, and eolian clays, silts and sands in the northern portion, all underlain by the Upper Unit of the Cretaceous Age Pierre Shale (Tweto, 1979). The Anderson property soil is classified as a Wiley- Colby combination. Wiley-Colby combination soil belongs to NRCS Hydrologic Soil Group B . (Soil Survey of Weld County, Colorado, Southern Part. Soil Conservation Service. September 1980.) Vegetation on the site consists of some native grasses and weeds as well as various wheats and alfalfas. Some cottonwood trees are located around Foster Reservoir and around the existing retention ponds. Refer to Appendix D for Developed Drainage Calculations. Construction of the proposed development may require placing fill within the 100-year floodplain boundaries. If this does occur, the required LOMR/CLOMR shall be submitted to the authoritative committees. • 2.0 DRAINAGE BASINS AND SUB-BASINS Discussions in this section correspond to the Historic Drainage Plan located in back pocket of . this report. The majority of the Anderson property historically drains to the southeast and ultimately into the St. Vrain River. Refer to Appendix B for Historic Drainage Calculations. The southwestern portion of the property receives off-site drainage from the north, which is also the location for the proposed St. Vrain Valley School District High School No. 5 (Basin H2). Offsite drainage from north of the Anderson property is conveyed directly into Foster Reservoir. There are two major existing drainageways on the property, the St. Vrain River and outflow of Foster Reservoir. The St. Vrain River runs along the southern border of the property, while Foster Reservoir is on the far north end of the property and is partially surrounded by the . property. The outflow from the reservoir is currently conveyed through the existing spillway Channel. It is proposed to be relocated to the South East portion of the reservoir. These two existing drainageways have FEMA floodplains associated with them which are delineated in the FIRM maps located in Appendix A of this report. Foster Reservoir is within the northern portion of the site. This reservoir is owned and operated by the Highland Ditch Company. The reservoir is 173 surface acres and stores, on average, 1,670 acre-feet of water and has the maximum capacity to store 2,704 acre feet. The southern • portion of the property drains directly to the St. Vrain River. ID -2- I • There are also several irrigation ditches which currently cross the site. They are as follows: • Highland Ditch . • Ditch between the Sanborn Reservoir and the Highland Ditch • Ditch to serve Gerald Bacon's property • Ditch to serve the St. Vrain Valley School District Property In addition to the existing ditches throughout the site there are also four ponds in the southern portion of the site, one of which is proposed to remain. Historical Basins H1 and H2: Basin H1 and H2 are the historic basins. Runoff generated in these basins sheet flows south and towards the St. Vrain River. The flow generated in these historic basins during the 5-year storm is approximately 73.95 cfs. At the center of the property is the outflow channel associated with Foster Reservoir which conveys the reservoir's outlet flows into the St. Vrain River. The Historic Drainage Plan is located in the back pocket of this report. 3.0 DRAINAGE DESIGN CRITERIA The drainage design criteria were taken from the Urban Storm Drainage Criteria Manual dated • • June, 2001 and revised August, 2006. This criteria was followed in accordance with Weld County Code, Section 24-7-110 through 24-7-130 and Section 8-11-10 through 8-11-150 as well as the Weld County Storm Drainage Criteria Addendum to the Urban Storm Drainage Criteria Manuals, dated October, 2006. Drainage basins for the pond design exceeded 160 acres in size; 5 therefore the ponds were sized using the CU TIP method in conjunction with Urban Drainage criterion. The program entitled CUHP 2005 by Urban Drainage was used to generate hydrographs, and the program entitled EPA SWMM 5.0 was used to size detention. The Rational Method was used to calculate the developed flows for each sub basin. "C" values were determined using the Urban Storm Drainage Criteria Manual (See Appendix D). The rainfall depth-duration curves were generated by CUHP using 1-hour rainfall data obtained from figures RA-2 and RA-6 of the Urban Drainage Criteria Manual. The 5-year storm was used for minor storm calculations, and the 100-year storm was used for major storm calculation. This information can be viewed in Appendix B. 4.0 DRAINAGE FACILITY DESIGN Developed Runoff All runoff from the proposed site will be ultimately directed to the St. Vrain River as it is historically. Detention, water quality, and erosion control facilities will be implemented in the • design of the site. The overland flow length for each basin was calculated using the longest flow path distance from the uphill side of the basin to where it exits the basin. 5 -3- • • • • • The proposed site is divided into five major drainage basins (D1 through D5) and a detention • pond is proposed at the downstream end of each basin. All of the site runoff will be collected in • the site's proposed storm sewer system and directed towards detention ponds that will control the • release into one of the channels associated with the Foster Reservoir (Hydrologic and Hydraulic • Analysis Proposed Spillway and Channel Highland No. 3 Reservoir for Waterfront at Foster Lake dated June 2007). The spillway and breach channel for Foster Reservoir contain a low- • flow channel that will convey this runoff to the St. Vrain River. The total runoff released into • the St. Vrain River will be limited to the 5-Year Historic release rate as required by the criteria • developed by Weld County. It is proposed that the breach path and spillway will be resized and • realigned. Meetings with the State Engineer's Office and ditch companies regarding the proposed design have taken place and we are currently working to resolve all of their concerns. • • The total runoff that will be discharged into St. Vrain River from the proposed development will . not exceed the historic 5-Year release of 73.95 cfs. Proposed Basins, Sub-basins and Detention Ponds • There are five proposed major basins that are divided into sub-basins which convey runoff to the five detention ponds. The numbering system of the proposed ponds corresponds to the numbering system of the proposed basins. Historic basins include one basin for the entire Anderson property and one basin for offsite flows generated on the high school property. II Basin Dl: Located at the northwest corner of the property Basin D1 is bounded at the north by the Kitely Farms property and Foster Lake Reservoir. The west edge is bounded by WCR 7 while the south will be bound by the future alignment of WCR 28 and the east by the current Clear Day Breach Channel. Basin D1 will have five sub-basins with all of them conveying flow southeast to the proposed Pond #1 through both gutter flow and storm pipe. Pond#1 will store a volume of 24.2 ac-ft during the 100-year storm. Pond#1 outfalls into the proposed Clear Day Breach Channel and ultimately into the St. Vrain River. Basin D2: ' Basin D2 with four sub basins is located east of basin D1 and to the south of Foster Reservoir. ' The proposed alignment for WCR 28 will bound the south end of the basin. This alignment allows for the Clear Day Breach Channel to run along the north side WCR 28. Basin D3 is just east of Basin D2 and east of the proposed channel running north and south in the eastern portion of the site. A small portion of this basin is located to the south of WCR 28. This channel ties ' into the existing alignment of the Clear Day Channel and ultimately outfalls into the St. Vrain ' River. Although this channel is the eastern boundary of the basin, the basin conveys runoff through gutters and storm drains to Pond #2 at the center of the basin just north of the Clear Day Channel. Pond #2 will store a volume of 10.7 ac-ft during the 100-year storm Pond#2 outfalls ' into the proposed Clear Day Breach Channel and ultimately into the St. Vrain River. The • I -4- I I • S • • • • Anderson Property is located within Basin D2. This 5 acre parcel designated as H3 will be left as historic flow and will not be developed with the rest of this basin. • Basin D3: . Basin D3 is located along the northeast corner of the property. Foster Reservoir is also a boundary to this basin. Foster Reservoir is located along the northwest portion of the basin while the eastern portion of the basin abuts to Interstate 25. WCR 28 also runs along the south edge of basin while Basin D2 bounds the remaining edge of the west side of the basin. The flows from Basin D3 with five sub-basins convey runoff south and west toward Pond#3 through both gutter . flow and storm pipes. Pond #3 will store a volume of 3.1 ac-ft measured with one foot of freeboard. Pond#3 outfalls into the proposed channel and ultimately into the St. Vrain River. Basin D4: Basin D4 and the nine sub-basins within it make up the majority of the southern portion of the property. It encompasses the western area south of WCR 28 down to the St. Vrain River. Along . the western edge of the basin lies the St. Vrain School District#7 property and the Adler property. The eastern adjoining basin boundary is Basin D5. The flow from this basin is conveyed south through storm pipes and gutter flow to Pond #4 at the center of the basin. The pond is in the approximate location of the largest existing pond. Pond #4 will store a volume of 20.2 ac-ft during the 100-year storm. Pond#4 outfalls directly into the St. Vrain River. . • Basin D5: Basin D5 is adjacent to and east of Basin D4. To the north of the basin is Basin D3, to the east is Interstate 25 and to the south is the St. Vrain River. This basin with three sub-basins will also flow south as the majority of the site does historically. This flow is directed to Pond #5 at the south end of the basin through gutter flow and storm pipes. Pond#5 will store a volume of 6.6 ac-ft during the 100-year storm. Pond#5 outfalls directly into the St. Vrain River. Neighboring Flows The neighboring flows are only from the high school property west of the Anderson site. The • flows from the northern neighboring property convey runoff south into Foster Reservoir. The offsite flow from the future high school site convey southeast onto the Anderson site. The 100- year flow from the high school offsite basin is estimated to be 35.93 cfs Hydraulic Analysis, Storm System, Pipe Sizing, and Outfall Design Sizing of storm sewer components will be completed for final submittal. StormCAD will be used to model this system. Storm system flows will be directed into detention ponds before ' being released into the St. Vrain River. • 1 -5- p I . • Groundwater The groundwater in this site has been carefully evaluated. Recommendations from the Geotechnical Due Diligence Study for the Waterfront at Foster Lake, completed by A.G. . Wassenaar in April 2006; and the Groundwater Occurrence at the Waterfront at Foster Lake . PUD, Anderson Farms Property prepared for the Colorado Geological Study by Tetra Tech in July 2007, were followed. The whole site was graded such that basement foundations are 3-4 feet above the high ground water levels. An underdrain system is planned for the site and will serve as a conveyance for surface water that infiltrates the soil around the foundations. Temporary/Construction Erosion Control Measures During the construction phases temporary structural best management practices (BMPs) will be . utilized to ensure that sediments and other pollutants are not transported off-site. The temporary . structural BMPs will include: silt fence, vehicle tracking control, straw bale barriers, and inlet protection. Please refer to the enclosed Erosion Control Plan for the locations and type of BMPs to be used. . Anderson Water Quality Feature Design The water quality feature designs shown with the Waterfront at Foster Lake Final Drainage Report and Construction Plans are based on design criteria which have been developed by the • • Urban Drainage Flood Control District and are found in their Criteria Manuals, Volumes 1 . through 3. Foster Lake Spillway Analysis . The hydrologic and hydraulic analysis associated with Foster Reservoir and Clear Day Breach and spillway relocation is located in the report entitled Hydrologic and Hydraulic Analysis Proposed Spillway and Channel Highland No. 3 Reservoir for Waterfront at Foster Lake dated June 2007. 5.0 CONCLUSION . In conclusion, the proposed development of Waterfront at Foster Lake will not adversely affect . the existing drainage facilities or drainage patterns surrounding the site. Runoff from this site will be conveyed through the streets as well as a series of inlets, pipes, ditches and ponds. Storm runoff from the site will eventually be released into the St. Vrain River at a rate equal to or less then the historic 5-yr release rate. Several permanent detention ponds are proposed to treat the water prior to the release into the river. ▪ • -6- I S S . • 6.0 REFERENCES 1. Weld County Code. Sections 24-7-110 through 24-7-130. 2. Urban Storm Drainage Criteria Manual Volume 1 through 3. 2001. 3. CUHP 2005. Urban Drainage and Flood Control District 4. Urban Drainage and Flood Control District website. www.udfcd.org. 5. FlowMaster 2005 by Haestad Methods, Inc. 6. EPA SWMM 5.0. U.S. Environmental Protection Agency . 7. Geotechnical Due Diligence Study-Waterfront at Foster Lake. A.G. Wassenaar, Inc. 2006 . 8. Hydrologic and Hydraulic Analysis Proposed Spillway and Channel Highland No. . 3 Reservoir for Waterfront at Foster Lake. Tetra Tech, June 2007 . RAl5l 61_002_andcrson\Documents\5161_002_04\drainage\report\ChangeOfZoneDrainageReport(062807).doc IDyr di ▪ • • -7- II • APPENDIX A 0 REFERENCES S•• w • • S VICIIIITY MAP .0 ..ii.,-.7-- 4.[:,-,,,,. :::: iiiil,rii ...,.„4_,E,Li'l: ::' .. l II yaziOt„AND 1 1 • t 1 z . otECir <x C ORADO HIGHWAY 66 ■ - . Ill a r1ol � � ♦� , . KITELEY � .�� 1:� 3 Ott . CENTU( ' r,2IT-T T* FARMS c �, 27 7 26 • SLATER _ • THE T _Foster Resew it S nborn • R SeN01f AT OSTER LAKE �• ire„ / �___ ,..:-....:..tea/aa/� _ / ./ o• i71ItJk ; / iyy, \\ ,-9 " / -?,1_71:-4 .0,Ic � }Me iisecRisn • Z J T EGRIST _.—"_'� • 1111, • / BACON _ %v�_J • o Rg , U O — • V. ATE PAR: _ / Q • ` 3Q �- 2 • / I I J , it I • • e 0 1000' 2000' 4000' Milit TETRA TECH RMC 1900 S.SUNSET ST.,SUITE 1-F.LONGMONT,CO 80501 • • TEL 303.7728282 METRO 303.665.6283 FAX 303.665.6959 06/23/06 ALS 1 O F 1 • SCALE: 1 " = 2000' JOBS 8 80-51 61 .002.01 • • • 8 D 82 i 82 1. .: 16 `a 79 ` ID - !.. .r e 1fi ce-- '�., r . '' -. . . U/A %ilia - 82 ID lc. f f f�ID 1 y 5q' f, .� t [ ` 8P1 *.: 1,f..1 . ,4i rrYT ' k eh: ..Wi..-n: t ERVO!' �1� ", ."z , ID 9�r 4` nillitSbk+ ' - 4 tJ /ID Milli 82 r t ii 81 s ID 11 ID ID _ 82 ' '� r ID Z �v Y;' 1. x*1 _ N gi ID � � � L � A f LAST 3 1}34...- :Pi t'aat, { f` Ill }a" ₹ ,,;;f4-.- n ,/c f '1,::::-.:'-ft.tv' $g ...Fs .its s a+,•`� , . : ,. i, ::. ID iii L: eil. • s• x yr._,St 10 X' ,. 7 >ne4,g$` `( ^ x m.r Ye ,-,,e;,&., 4 ink Q '� • l ''%°` '%° -`f*• 'it - } .tl q' _ T ri .y b yy� -L�' a' ID i �.iAir ' Y- iY .7 j� { 3 a a� 1 ` AT S Pf <f •• t b cars i >•Y' ` ,,.r s 'i� lb ,t ; ,-,k,•1!,"--4. . f F ';',";1-?..44t., f' ''At -' ' } ti - 48 4" . . r } t S 51 ID - _. Wes. :� e 5 .. IP II • 132 SOIL SURVEY II TABLE 14.--SOIL AND WATER FEATURES ID • (Absence of an entry indicates the feature is not a concern. See text for descriptions of symbols and such . terms as "rare," "brief," and "perched." The symbol < means less than; > means greater than] • Flooding High water table Bedrock . Soil name and Hydro- Potential map symbol logic Frequency ; Duration Months Depth Kind Months Depth Hard- frost . group ; ness ; action Ft In . 1 , 2 B None --- --- >6.0 --- --- >60 --- Moderate. Altvan II 3*: . Aquolls D Frequent---- Brief Apr-Jun 0.5.1.0 Apparent Apr-Jun >60 --- High. . Aquents D Frequent---- Brief Apr-Jun 0.5-1.0 Apparent Apr-Jun >60 ---p High. II 4* --- Aquolls D Frequent---- Brief Apr-Jun 0.5-1.5 Apparent Apr-Jun >60High. . Aquepts D Frequent---- Brief Apr-Jun 0.5-1.5 Apparent Apr-Jun >60 --- High. . 5, 6, 7, 8, 9 B None --- --- >6.0 --- --- >60 --- Moderate. Ascalon • 10 A Frequent---- Brief Mar-Jun >6.0 --- --- >60 --- Low. . Bankard . 11 , 12 B None --- --- >6.0 --- --- >60 --- Moderate. Bresser II13 A None-- ___ --- >6.0 --- --- >60 --- Low. Cascajo II 14, 15, 16, 17 B None --- >6.0 --- --- >60 --- Low. III • Colby II 18*: Colby B None --- --- >6.0 --- --- >60 --- Low. • Adena C None --- --- >6.0 --- --- >60 --- Low.II 19, 20 B Rare --- --- >6.0 --- --- >60 --- Moderate. . Colombo II21 , 22 C None --- --- >6.0 --- --- >60 --- Low. Dacono II23, 24 B None to rare; --- --- >6.0 --- --- >60 --- Low. Fort Collins II 25, 26 B Rare to ;Brief May-Sep >6.0 --- --- >60 --- Low. IIHaverson common. II27, 28 C None I --- --- >6.0 --- --- >60 --- Low. Heldt II 29, 30 A None --- --- >6.0 --- --- >60 --- Moderate. . Julesburg 31, 32, 33, 34---- B None II '-- --- >6.0 1 >60 ---___ ___ :Low. Kim II 35*. Loup D Rare to Brief ,Mar-Jun +.5-1.5 Apparent Nov-May >60 --- ;Moderate. . common. IIBoel A Occasional Brief Mar-Jun 1.5-3.5 Apparent Nov- --- 'pp May; >60 ,Moderate. . 3M*: Midway D None --- --- >6.0 --- --- :10-20 Rip- ;Low. II pable; IIII • See footnote at end of table. II II II .). , II x: A ` , Ar U ID WELD COUNTY, COLORADO, SOUTHERN PART 133 II TABLE 14.--SOIL AND WATER FEATURES--Continued . Flooding High water table Bedrock IlliID map name and Hydro- Potential map symbol logic Frequency Duration ;Months Depth Kind :Months Depth Hard- frost group ness action ID I Ft In i Il3 h S i Shngle D None --- ; --- >6.0 --- ; --- 10-20 Rip- Low. . i pable 37, 38 B None --- --- >6.0 --- --- 20-40 Rip- Low. p) Nelsonpable . 39, 40, 41 , 42, 43 C None --- --- >6.0 --- --- >60 --- Moderate. . Nunn . 44, 45, 46, 47, 48 B None --- --- >6.0 --- --- >60 --- Low. , Olney . 49 A None --- --- >6.0 --- --- >60 --- Low. Osgood . 50, 51, 52, 53---- B None --- --- >6.0 --- --- >60 --- Low. Otero • 54, 55 B None to rare --- -- >6.0 --- --- >60 --- Moderate. II Paoli . 56, 57 C None --- --- >6.0 --- --- 20-40 Rip- Low. Renohill pable Ill58, 59 D None --- --- >6.0 --- --- 10-20 Rip- Low. . Shingle pable 60•: ', Mingle D None --- --- >6.0 --- --- 10-20 Rip- Low. I) RenohillRenohill C None --- --- >6.0 --- --- 20-40 Rip- Low. . pable 61 D None --- --- >6.0 --- --- 10-20 Rip- Low. Tassel pable li62, 63 B None --- --- >6.0 --- --- 20-40 Rip- Low. Terry pable 64, 65 C None --- --- >6.0 --- , --- 20-40 Rip- Low. IllThedalundpable ID 66, 67 ; C None --- --- ; >6.0 --- --- >60 --- Low. Uim Ill 68• A None --- --- >6.0 --- --- >60 --- Low. II Ustic Torriorthents 1 69, 70 ; A None --- ; --- >6.0 --- --- >60 --- Low. , Valent in 71•: I 1 Valent 1 A None --- --- ->6.0 --- --- >60 --- Low. . ---Loup 1 D Rare to Brief Mar-Jun t.5-1.5 Apparent;Nov-May >60Moderate. common. • 72, 73, 74, 75, I 576, 77 1 B None --- --- >6.0 --- --- >60 --- Low. Vona II I , , See footnote at end of table. • ,' F. L • 134 SOIL SURVEY • TABLE 14.--SOIL AND WATER FEATURES--Continued • • Flooding High water table Bedrock_ . Soil name and :Hydro- Potential map symbol logic Frequency Duration Months Depth Kind Months Depth Hard- frost . ;group ness action Ft In . --- >6.0 --- --- >60 --- Moderate. 78, 79, 80 C None ---i . Weld . 81',W 82', 83': -__ >6.0 --- >60 --- Low. Wiley B None --- --- --- >6.0 --- >60 --- Low. Colby B None --- --- • • See map unit description for the composition and behavior of the map unit. II 4 c.. LLo cc at CD W z m O en h y W O o = co W /� FO = O U Q A M Z 4 �JJl [r] to W 0 6. ¢ W l G!'�ct ^ w = 0 a L h z = H O a d 0 w Q ^ � O LL.0 IL H K 0� -o h O x o o = I o C_ o WToT\ o�\ z4 W o U. Lti = lip � VU6 ay 1 \ — eii .4 0 N n t .t. 0 '000 n 00Y oO . 20 O N O n 0 N Z vat^. o ^ p ccc `^c ; o_.000 n 3u 3 � c u c E v m ^ X `0 O o ,,y LT C "�q j s, q8 ^tts .0.00 T° c "ud t �v �v O iO J M G O Z u NL 'T 1 T. CO C' O �50-0 0 >t >r e0r 9 c... o O p C V O N N O C7 Z 'o E .uio .s- o 2uC y$ u � o go- 6 .a $ °o too 0 u o N o s o.'o v c c coo t. cuv � ._ 3C 3C y v `u O ~ $ E o—°c g ° o Z . 0 ,22 ?a A = $ o c 'oro 37 Q ._.._ r > a 0 L y .5 c o C y 3 N ^ y ° 0c' C 0 W Z . Y OO „ 0 0 t,_ O E 1, '> ,Z 0 C 0 — c 2 a o a a 5 E "ii t._ a ° c a N o 0 0 cy °sv ea v } L N w c c 1 0 •,—Q _3 h i o �i l 0 c u u v- l7 iy Cn^ —o C u E o E•, u v 9 c g. v o W ° c c O aq t.• c � ,.cM • >o .SC _ Quo c ; u i° tp Y o o o o C . LL N Y 2 z 0 C o ° O c' c o ' O O 0 , g M F Jr,ZN I'' c br` Y_ 0 O p c 0 c C V c i' z O N p E C O E O u D v• ' 0 o g EuwE vNE c „ ;8ncwt" E ° -LIFE '�u ' o • _ o 'o g °. 05 u y _ tot: `o3vv `o3cd oA o2c 0 °owc of o .O. ...,15 oac co co C m pm ''! ,c to,- z O 2 t O O ] 0 0 0 0 O O V C ,!•,), g V O Z d ° 0 Y v u t >9 0 ° V O y 0 u 0o Or 0 V V y r V r V ° ° m o w o e Q ¢w ¢ qo n Q Av el a c Q 'a-V, Q a.°. Ef Q < ¢ A °c Qno W LL ▪ v t C J 8 c ^ n 0 O u d • O u u } Y Y } LL W LL e X w O in c 0 0 o' o m 3• m 3 w cC . * 0 <. Q Q 4. �. .m .V_.0 yr - N .. e N Q ? oI I 0 1 � ul v_ 1 N N m • r ) li to D tch ,f i:1 r E I I ..------`p,or cnc yr- $ z � z o cc 04, =_ 0 / W _� i, N. m M 0 0 0 If II / 1 II 1 _ O S •• ▪ • • • APPENDIX B • • HISTORIC DRAINAGE CALCULATIONS • • • • • • • • • ••• • • • • • • • • • • • • • • ••• S S . • Comment Weld County 5-YR Depth Duration Curve ,Hr Depth 1':3$ Return Period 1;5 Years . Time Depth CurveValue 0:05 0.027 0.02 • 0:10 0.05 0.037 0:15 0.117 0.087 0:20 0.207 0.153 0:25 0.338 0.25 . 0:30 0.176 0.13 0:35 0.078 0.058 0:40 0.059 0.044 . 0:45 0.049 0.036 0:50 0.049 0.036 0:55 0.041 0.03 1:00 0.041 0.03 . 1:05 0.041 0.03 1:10 0.041 0.03 1:15 0.034 0.025 1:20 0.03 0.022 1:25 0.03 0.022 1:30 0.03 0.022 . 1:35 0.03 0.022 1:40 0.02 0.015 1:45 0.02 0.015 • • 1:50 0.02 0.015 . 1:55 0.02 0.015 2:00 0.018 0.013 . 2:05 0 ▪• ▪ • Comment Weld County 100-YR Depth-Duration Curve 1 Hr Depth 2.65 Return Period 100 Years . Time Depth CurveValue 0:05 0.027 0.01 0:10 0.08 0.03 . 0:15 0.122 0.046 0:20 0.212 0.08 0:25 0.371 0.14 . 0:30 0.663 0.25 0:35 0.371 0.14 0:40 0.212 0.08 • 0:45 0.164 0.062 . 0:50 0.133 0.05 0:55 0.106 0.04 1:00 0.106 0.04 1:05 0.106 0.04 1:10 0.053 0.02 • 1:15 0.053 0.02 . 1:20 0.032 0.012 1:25 0.032 0.012 1:30 0.032 0.012 ID 1:35 0.032 0.012 1:40 0.032 0.012 1:45 0.032 0.012 ▪ • 1:50 0.032 0.012 . 1:55 0.032 0.012 2:00 0.032 0.012 2:05 0 P A 6601 2LA 16061'OVA 2$252111E0C13NOHd to } 10505 OG61 DW 0100,1NONOl A]3111150 3301013SNn3 1111100 0061 > 8 d u i y,3 0IHOISIH \ NV1d 3`JVNIVH0 $E & r e H331A131 © p 9 r Vld3NO2d03 NVHJ RR t1 NO ssimons M n IIINI xxxI 3NV18313031v1NOHJ1131VM 3H1 € € M 0 I¢ 53 NOILdI00000 31v0 �NyrW! Fil� or 1 � o . f 1 /7 4 '�a Y.i tlLL /T, -e-2rs 2"� Q? e n NA.. I ft,J — ,iii,, N 1 n n I� Y r 6s i J^M{ FA i. v ,, Xl u L'�.6 .x, r� � >` � my�, .� N r s 0 1 ill � J 3 1 , e f ,!, 1 }-- t_,. i rr h. 80'0 J 0'SZ 0 "3 H l 1." a __ ii iy '7 C I1 F, i X�B 'r.1 , 1 �1LfU F{s 60:0 SJ L06ZS ' ` 2 it wi; i ',,,,,,.- ---"---1 ' , . --..-.4-,., \ 0" EE 1.1 a % § wo M >�'ra ,ate Pn+s.4-µF F'�'tt" Y ,.. u icl1 0 9 $ I � e = N �.., _ i „ r, y �\[ J r t ' r. — w a 1, 1 ` a , d 2 W - IT i —_T _ : 1 0 T w o m f 93a is 50305-3135530011 00551530 JI3OISIH incur,050 0-013'SSue d 350,0500 39VNIYH01SIDS ueldl6,9 uo lep l?000 00151:5 9515 l0 'le n,00 L L002'121e0N AaWOW S S^� uI 1 S r. Pxtii kin 1 xxxi N 'II Logo 0000 q + 5�y�3vy . I 000 fait �,:;i 0 0 0 0 Via - E ILI ,:, `s , 0 'Li0000 r III Liz, .1..1., Et f,rii gz,fr oo° s §.§§§ Pi it too- 10006 “I J0000 2 22 ri S il 3 E J, En st __i.° j0000 'O E r5 ELL, v 5 . E E a 6 o u0, N_ _nn s, S2 u II--g- Y E q v te) 5E ` A v � :i m 0 as - I i ': E t" S `- . sA-Eit•ic Cu" - 5tJMM Link This sheet is used to map CUHP subcatchments to SWMM nodes. • CUHP Catchment to EPA SWMM Node Link Table CUHP Catchment Name I EPA SWMM Target Node H1 J6 H2 J7 . H1m J8 3 tv\\ H2m J9 nor 5'tor • 9 S Sc d N CO Q r 0.-3 E . "n m` o e O ' _ nnOr . - ≥ N ,-co o N � N n a �n Z ti 0 . • E lc' "n ° ° o . N u O n a 0 co N 0. 2 d1 Q N l? U U U n• 0 C n W - i W — N r N 5 a CO N d N N CO CO . m t - -0 0 X U W X C S E 0 M m M . G Q m m m m m CO o . > N N ONO N IS N m ° . LI N m 0 . a N r N r w . d A C CJ t7 9 E a E II m < M v re C. N N S ^ 9 Si pF g O N f N A d d N m O 0 y O O O O • ... E eN C l Q •] Q • q a 5 • CO a CO� d y N 1 • MO 4 N m r m n -o co . ^ N LO N N C C • O D Ndnn�N i E 3 E d . > 0 o r o cJ N f] N • 00 a o 0 0 0 co • a re a mdmm m ,- NWr ‘r r N . a _ o o O 0 o • Z U C C m Sc—) o = • E r o • m a o d • M J E . E Y E a E • E U CO N y o J• O. 6 t o0 5,5 N N • ` V V U U O O 0 .3 O a N_ _N N_ • D nix 2 N r N_N t Z • Y_ o S . C E J E • `o i • c m d E E E L • lo E E _ N a 2 2 S 2 • 0 I D '' 11 s - YfZ & Ina-`� � ST�RNLS . �T� 5�� c I I . . • • .._. • _•. :, 'It - ,, 1 t .1 i' ID • •. • • •.;•••=,,•,• .-...._. - - .'.:' :.;-_--"...:;:;;;;:.1,• ` -:: ., ..r:. ter. ! t . i • { r r r t s ; pg 06 1_., • ti� •'07i i, • ID 0 ? • -LH' ;1.•,:;i_ ...-t � °- . I 1 • 08' -;':;.. -4--•••:',..=-7.r - ' 1 09 ` •'` ` . . • II II II II 1 EPA S kimin OkTp,t#• /C }{ hs}orlc) li liEPA STORM WATER MANAGEMENT MODEL - VERSION 5.0 (Build 5.0.008) li ID AnalysisOptions • « ««*«««Flow Units CFS llFlow Routing Method KINWAVE Starting Date JAN-01-2005 00:00:00 . Ending Date JAN-01-2005 06:00:00 Antecedent Dry Days 0.0 . Report Time Step 00:05:00 Routing Time Step 60.00 sec li li ************************** Volume Volume Flow Routing Continuity acre-feet Mgallons li Dry Weather Weather*Inflow 0.000 0.000 0.000 Wet Weather Inflow 0.000 0.000 . Groundwater Inflow 0.000 0.000 RDII Inflow 0.000 0.000 . External Inflow 87.732 28.589 External Outflow 87.732 28.589 llSurface Flooding 0.000 0.000 Evaporation Loss 0.000 0.000 liInitial Stored Volume 0.000 0.000 Final Stored Volume 0.000 0.000 . Continuity Error (%) 0.000 . Node*Depth*Summary S . Average Maximum Maximum Time of Max Total Total Depth Depth HGL Occurrence Flooding Minutes . Node Type Feet Feet Feet days hr:min acre-in Flooded J6 JUNCTION 0.00 0.00 0.00 0 00:00 0 0 J7 JUNCTION 0.00 0.00 0.00 0 00:00 0 0 . J8 JUNCTION 0.00 0.00 0.00 0 00:00 0 0 J9 JUNCTION 0.00 0.00 0.00 0 00:00 0 0 06 OUTFALL 0.00 0.00 0.00 0 00:02 0 0 . 07 OUTFALL 0.00 0.00 0.00 0 00:06 0 0 08 OUTFALL 0-00 0.00 0.00 0 00:06 0 0 ID09 OUTFALL 0.00 0.00 0.00 0 00:06 0 0 • :....:..x..«.«.«« . Nod* FlowSummar'y « « ' li . Maximum Maximum Maximum Lateral Total Time of Max Flooding Time of Max . Inflow Inflow Occurrence Overflow Occurrence Node Type CFS CFS days hr:min CFS days hr:min II J6 JUNCTION 532.90 532.90 0 01:05 0.00 . J7 JUNCTION 35.93 35.93 0 00:40 0.00 . .. _ 5_ye. H isto O G �CLEhsE 06 OUTFACE 0.00 532.90 0 01:05 0.00 247E 07 OUTFALL 0.00 35.93 0 00:40 0.00 • 08 OUTFALL 0.00 68.97 0 00:55 0.00 . 09 OUTFALL 0.00 4.98 0 00:35 0.00 ID II li SWMM 5 Page 1 II II II II S . II . Outfall Loading Summary II IIFlow Avg. Max. Freq. Flow Flow . Outfall Node Pcnt. CFS CFS II06 98.61 153.71 532.90/6/��.JOr S+6 r••••• 07 54.44 11.60 35.93 II OB 98.61 18.61 68.97 ^/� 09 49.72 1.39 4.98 Iv ` nor S VD CM IISystem 75.35 185.31 628.80 II * • «*k * Link Flow Summary II IIMaximum Time of Max Maximum Max/ Max/ Total Flow Occurrence Velocity Full Full Minutes IILink Type CFS days hr:min ft/sec Flow Depth Surcharged . P6 DUMMY 532.90 0 01:05 P7 DUMMY 35.93 0 00:40 IIP8 DUMMY 68.97 0 00:55 P9 DUMMY 4.98 0 00:35 II IIII . Routing*Time*Step*Summary II * * ******** Minimum Time Step 60.00 sec II Average Time Step 60.00 sec Maximum Time Step 60.00 sec . Percent in Steady State 0.00 Average Iterations per Step 1.00 II Analysis begun on: Thu May 03 08:02:40 2007 IITotal elapsed time: < 1 sec II II II II II II II II II II II II II II . SWMM 5 Page 2 r 0 •• r • • APPENDIX C 0 • DETENTION POND SIZING CALCULATIONS • • • • • • • • • •• a • • • • • • • • • • • • • • • • urir',FT tbiglk Vkw tie ss OK € EEEE €8$ r lilliii 'e oo o8 o 8 o 000838E I SZ 111 r Vit, a 6u a 4 a A 4y 000 000000 100""' , 000000000 0 0000000 A .0.0"0.0 0000 00.00000000.0. yi Doh 0>00oo eee WADWil tanngitg'II` tip` ev ! Ioe 00000000'00 Wc. a _ emem mmm PxE1aa8888sos8888s , g eee e O s, ba€ " g00000000e00000 III 1, . E' * 4nooaoonnnnnnn 9 , g0 00000006 ' E , �0 8r7,*AOr 6li Q "1, s, e$ aE 3 g g "s"s"sssg"sa"s"8= 0i //S� .a�, 2 O— 00 000a 0— n ' e 65 gy 92"P.82,192 `9= a" SEOOOO oe8o 00 Q- It ; £aY I; 0 a 0'00 000 E' tr 4EE EJ. J >G `J P _ E- 14'SEac.:i §a eeE jV E e o a e Fc m zzzz • �vki i,4 iii, vi pp,, �JJJJfe££= oo ? . E' 0000� 9g �00 d O ss n- 2 so9ao "pooao O € 33333333�333 7 E a /d S S om -gi F-r .06 °?, o Fr-.11 a E$r. "aE fl EEEEE_xz_EE me' B .- Sc888oee3ozx eco<Btt IW[1,1Yd LIN LI!lcoc): 110Hd 6 3 10000 OOVdOIOO"1NONONOF d'1311115 133015135X05 vN p O50081 - �,v,.1.,N1..... .>� '11Vel3AO 3 3 ! °die a { NHId 3OVNIdgI0 (N F H331VRI131 KIEL a qd° kind allozdoaONVH3 p $ m m t—� 3X01 tl31SQd 1V 1NOLatl31VM F IAB NO11dISJ53O 3100 I<MIN i 11 Ie rIl Z CO ,: - ` # F f11 g ` 1 J'. e I III % il t ICI / \ \ / ;; n�m�� fuu► l� N ��u�� uu 1 r---,, 1 .. J a v e � .I III 21 i 11 I— � �0ayl , F J X5.!!1 % :✓ I J ��l _ air - li►� ,(t zX f'. _ ,s _.ter _ ,3YQ:i6i® 111 `� 1 RBI { / i p 1 :, ' ii � y5 W --- p " a € _ � a �'� Ids, b LJI `f� ��iM �' 1 1 1 ° $ ir 'aS ! h. A. OC �" �I �r s. yY s 1/ �, _ ' w oW lC g a g ,2 o ! ,1. a6 ,c •C - - a- -- -- - I e i Vag »` , a e 3so I 1 24q ,, g` w 111- I .. } w -' , a �\��I v z I : ° u t< o In 63N110 N03003NVN N36l 33<O:1110101 DMO IW.udud)uqd<avulse<3OVNIV301 V5 u.Id16-NuouepollZOO IMO ONLNVtlo NV 54'01:11 IOW Cl.u^I"A.pWP•M S . • This sheet is used to map CUHP subcatchments to SWMM nodes. . ;';' a�HP Catchment to EFTA 5WllAlirde'L�nk halite . CUHP Catchment Name IEPA SWMM Target Node D1 J1 D2 J2 . D3 J3 . D4 J4 D5 J5 D1m J6 D2m J7 D3m J8 D4m J9 . D5m J10 III •▪ • 1. p . • L N N ytj O 001 n m O N N O n9 a '> Ov a.q tonain N ar : 5 o_ion 6 an 0ry n� a II2 N 7 0)N E le y 0 0 V1 0 m N n V01 . a.n a o N LL CO0g0,0 '-0°400 a 04 0n d n O N 1 0 t7 0 0 V 01 CO CO 0 0 IllO W 0 0 n M.a 1F)- N n 0 . 0 N n '" V a — 00 co r-- a fl . 0 N m 01 01— n N ut co 00000 tu n C W • an 0 0) f-)LO 03 0 0 N M !a� � tu 5(on _ o_I,- Ill ) V 6'F 00)81,2- INn 0 o in 0) N N O)m n N ID01'm tm0 m OV1 Y O t2 • aor n C) oc . a n n m nto my CO ^N c,n 6 1p N q C . E E a E y h 1 rcc m m- n o^ m= 0 0 . ws q 60in ea nn . ^ a y m 1 m an u)0 m n N N 0 0 5 E in rr — o ry m n n o r m ry O 3 5 E o. C4 m N tv r)CO Q_ C m CD 0,I-- C 1n co to -m in eu 0 tll LO 3 E — qqm `1 N el tt 1 C0)t0V N m m 0 N 43 a 0 0 0 0 0 0 0 0 0 0 ▪ d 43 m . Q m co 0 CO 0 0 0 el m m el _ 0 00.- 0 00 I q (j o O o O O O O O O o 0 0 It) o n co E co 0 0 d E M2 o 0 a m N O `rv o P m E E 0 q `m » 0. 3 t E € E € E € E € E E 8 0 0 0 o N N „ N co(flown) q t 0 0 0 0 0 = 0 0 0 C E E 0 E E E a to_, aN M o o 0 0 0 0 0 0 0 0 • o c o z III E q 0 E E E ' 3 2 E E E E E CO 0 0 0 0 0 0 0 0 0 0 0 O E PA SWMM DQ-Lt ks O • 01/01/2005 00:0510 • • • • J6 • JB • PI J] • POND1 • 01 P2 P3 S R1 POND2 • STR Cl • • C2 031123 PONDS • C3 • J9 • 04 J10 • P4 POND55 • STR5 PON04 • C5)iy • OUTFALLI str4 IX/TFALL2 • • • • • • • • • • • • • • • • • • • SWMM 5 Page 1 a II ID .S . a C a . Q L N • $4 a • - 0 • £ £ • £ 3 0) 0. • • a v v • - O ral C 0 W O H 0 0. Q 0000000000 • et Z 0 b o • H 0 0 H 1. M F f7 Z v .G F • a H 0 NI (n ❑ (Dona 0 0 0 0 0 0 • O H N 0 H 0 H N H • .a H 0 N m in -F 0 • L L O o 0 N 0 E L ry m E Q L-d O 0 0 0 0 0 0 0 0 0 0 • 0 • 0 H 0 H F M • N G L w (0L W 0 G N O C >� 1C ICI 0 0 0 0 0 0 0 0 0 0 0 H E ❑ 0 0 0 0 0.0 0110 .0.) O E 4 • 2 >\O\O\O O O O 00 Q b 04 .-10 HOHOHH (n In O H 4 • W H 33000000 on oo0H Fin 0 O N O H O H0 N 1 N 00H H 0 4 1 0 0 0 L LC) tn in C' m N d' L U Z 4 0 0 0 0 0 0 0 H 0 0 0 0 0 Z 0. 0 0 0 Z Z Z o H H a 0 > in Ln in Ln in r 4 n 10 m 0 > 0 • I > 0 m m m n m o W N N m > 0 N H H H N Q T 01 N N co O\ T 0) G N CO ❑ 10 W a P C C C a c c c v H W C • DI 14 E. X WF 01 to H • 2 O E. FI a Z £ 1 H FI4 a1F I En 1. W • OZ O) F a WH EOW3 > 2 Ell .. N H H W W Q Q a W H❑ ❑ W 2 W O o Q H 3 ZE QEr� F. E-.ZwCO 14 W F 2 co maa N I00 .]I WIZ4Q.. WW a' 0 2 W .H] it • ., ZDF aas OI EI HI FIQ � WIWI4 HIF H [Z[-..'I� 0))0000ii WI --Z a 46 < • F E. 01+. 04 NI 0 I 1 WOO 4 0. 0. ❑I❑I W W Q a E10 I>HIO a W H 2 2 O HIZ ..1 W NI U b .n r m m .oi a 1n m N H [H 0 e • 0. .] Z .] EE W W 22334' W W 40aZ4 W H00 HO) 0 2 hhhhh00000 0 Z 0 �_ E OG. H W Ul W 40) W W W W ❑❑ (K344H> .] ZZ0H a0 h .- ,- ; O U • • 0 II C C • 7 E • H 3 X O M ri Z W 0000 ° 0000o • • • -.1• O N L rW 0000000000 w▪ O Z Z Z Z Z • N rt Rl D. o o 0 0 0 • N LC 0 • a m m a v o .n a L'H x in i++ to in in a m a a r 7 N v C W a a a OW 0000000000 a 0 0 0 0 0 ° f-i in. < m .iH • o H o0 m • ..... H NH L v N W• 01 v A 4 • G al N"I O y NON .a m IQ H H H `1 ri H .'G 0 0 0 0 0 0 0 0 0 0 a Q' H m r ? V • .l .1 .] .4 .] • m m 00000 00000 ro 0 H 0irr .C v FHE. 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UUUUU • • • 0 U ill .P . a 0 a ID ID II a N O O • TD a P PP o u-, oMM O. o N m P a N N • N o ID r P- OD CT mm 0 en M 0 c 0 Ul 0 a N . r v 0 N ti Tr In N IllH 0 0 N 0H N N C r N 0 N N LIIH 0 0 M 0 N a VIN P N N N 0 a N M In 'i W N 0 P OI N N N H b a 0 0 0 b N N P N N IN O P 0 M 0 M 0 a O b N 0 N H H N en N M N > 00T- P r N r N 0 M O r IO O H Ip 0 O N M P P 0 H N Ip 0111 \00 r 0 0 OI N O N N N C O M M O r O N H b N 0 P O P b 0 O N N M N b h 0 OI O N N M 0 N b 10 0 OI N N M a N N0 } p N a r N H N N Cl 0 P P 0 In N N N N N N N N I0 W 0 1p IO`Lb l0 b LO In N N N N N N O P P 00 O N ID > N P b 0 Oa P b CO ry P IO 0 N0 VD 0 N P MOD N a b CO N P 1 N N P O CO X 0 " H H H H H N N N N N M M M M 1N P P P P P N N N N N IO IO 10 b TD IT r r r a a P ID H N O y 0 n m N N IU I O H0 P 0 4-I Try O N (I) u H r N 0 H P • W 0 W• � 00 0 N ^ X r r r k a P P P N CO w P a a jj IV E H TO O ID .— h W O M M M In G H H H H H H H H H H HH H H H N H H N H H N N Tit-1H H N H H H H N H H H H H � . NmN W N robb'0'0'0'0rorororororo ro'Ororobbrororo ro'Obrobrorob'Obbbbbbro Z o V P P a > S '0 0 C 0 0 0 0 0 0 0 0 0 0 C C C C C C C C G C C C C G C C C k C C C C C C C C c 4K b 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 C F - zx � �� uz . aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa ✓ S • Sco o 0 0 0 01 CO r1 r 1l1 N 0 b 0 00 0 0 0 N N 0 N 0 N N(lace P 0 T H N P CO P N N N CO r M 0 0 H H H 0 0 0 01 N b N 0 N 0 H 0 0 0 N 0 0 P O ry P H O b O N ry0 O CO N NCO 1� b Ol IO ry O 0 b P i"1 N N N N N N O . N 0 N Ol 0 Ol O r-I N O kti0 N N W N '1 O N N H b N N N P O CO C') q b N O1 H O\ WH U) P b 0 ON 'Cr CO CO 0 N P O 1� 0 N O N N PO N N N O H N H N H N N H H H P N 01 N CO O H N P N 0 O\ H N N N CO 0 0 O 0 N P CO N 0 0 el r [� h 0 0 0 0 0 OI .i rl ry P H P I- H H H N N t l l+l N P Y C P P C C N N JI Ill N N Ip b N COb b N N lO N . N 0 N P N CO N O N N C N CO N P N CO NO. N CO N P N CO NO.N 0 N P N N P b 0 N N 0 0 0 0 0 01 Ol H H H H H O H H H H H N N N N N I'1 NI N r•1 t+l P P P P P N N N N VI N N lO N 0 ii HHHHHHHHHHHHHHZ N N N N N N N N N N N N N N N N N N N N N N N N N N N N N N N N N N N • roO121 21rovrororo roro rororovro TI'0 v'CS'0 roro 01'0'0'CI'CI'0'CI'0'0 911'0'0 91'0'0 11'0 TI 11 r0'0 roro C C C G F C C C C C G G C C ro C C C G C C C C C C C F C C C C C C C 0 C F C C F C C G C C F C F C C O O O 0 O O O O O O O 0 O O C 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 a a a asaaaa P. aa0 a0, as a a a a a as a a a as a a a a a a a a a a a a a as as co p S Lc r S S S S S S S S . (0 T 0 CO to 0 0 0 H to 01 H P T N ID N. O CO to P H P T N m 0\O m m Vl a ✓1 fl x 0 0 0 H r O M N 01 m P 0 N N H H of 01 m P) m ID P 0 01 m au m 0 Cl H H .4 m 0) m m r H H O 01 0. 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H N W AW • N M M M M I'1 M M M M m M M M M M M M M M M M M M M z P P P P P P P P a V P P P P P P P a P V ILO ro ro rororo v ro v ro rororororo rorov ro ro TI rororo 21 21 v ro roro v vro Tit ro 21 TI V ro ro ro v ro rororo C'0 C C C C C C C C C C C C C C C CSC C C C C 0 0 0 0 0 0 0 0 OCOCC COCC C 0o . 00 . 0 . 0000 . 0000000000000 . 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 . a0 a s CL aa a s as a as aaaa a aaaaaaaa as a a a a a aaa a a a CL a s aaa U • S ✓ IP • . N N 0 111 to 01 P H N 01 H 1l1 H 01 0 01 N b M H N P P b N M 0 111 M fi r1 rn N N M 01 N 0 a to N 1+1 N Ci M 0 b N b O\ P 001 N H P O 0 N 0 . M P N b 0 0 H M N N 01 H 1+1 b 0 H p N 0 M 111 N V1 M 0 H O a 0 N1.0011110\ V101 ,11 01 111 H b N 01 0 N 0 Y1 N N P b 0 O N 111 N 01 H M b 0 O N 111 N 01 N P ✓I M P N O 111 111 0 0 0 N O 1(1 01 M N N H b H 1(1 O p N p 0 M 0 N N N N M M M M M Q P P p 0 1O N 1O N 10 b 10 H N N P N 01 01 N H b 0 0 0 H H N N M M P N 111 1(1 111 10 1.0 h N H H H H H H HHHHHHHH H H rl H N V N b 1� 0 01 0 H H H H H H H H H H H H H H H H H . O V. 0 N 10 p CO N 10 P 0 N 10 p to . O N N p tO CO CO p 10 CO N 10 CO N V 1D CO N P O O H H N NN M M C P p 1(1 0 1p b CO N p b 0 CO 01 01 H H H H H ri H H H HHHHHHHHH 0 . . . - H H H H H N N N N N M M M M M VI. P P P N 111111 m 0I Ocn b s. E to P p P P P P C C P P P P P P C P P p p a a C N 111 N N 111 1(1 111 in 111 111 111 Ifl 111 111 N N V1 111 ✓1 10 01 111 N 10 1O in • rovv vvrorororott Ottdrorororororo bvrovrororovrorororororovrorovrororoarorovroro 000000000000000000000'0 010 0 0 0 0 0 00000000000000000000000 . 0000000000000000000000 0 0000000000000000000000000000 aaaaaaaaaaaaaaaaaaaaaa aaaaaaaaaaaaaaaaaaaaaaaaaaaa 0 V N . a c 0 I r v N N N N H M N N o M o N H H H H I(1 H a N N N ✓1 0 r H t r N 0 M a 111 N M N M N 0 tT 0 % . O N N N N 01 H to H M H N H N H N H N H M H to H 0 H N N N N O M 0 Ol M lO Ol M 0 N H N M lO N 01 N 0 H l0 N N N b N t0 N 10 N N N N N IO M M N o H 1H N 0 M W 0 C to 10 O N N 1O N H H H H N N N N N N M in N N Ol N N N N N 0 N N O O N M N N M M to V 111 M 10 r t` 0 O O N rl N N N N N N N N N N N N N N N N N N N N N N M M M M M M M M M M M M M M M M M N N U] U . 0 N C N 0 N Y 7)- 0 N p 14?0 N C N F up CO N V' t0 0 ry C t0 CO N p N CO N C N Co . 000 0 0 H H H H H N N N NNNNNN N N N N N N N N NNNN 0 CO CO CO CO 01 N N Ot 0 HHHHHHHHHH H HHHHH H H H H r N H 1 0 • C . N N L t0 N � U O O 0 U Z cn an • I(1 JI N in in 01 in N N N 111 ui t0 V1 in to co in an in an N 01 in in 0 N m 0 VI 111 N11 in in tl 1l 01 OI in tO v W H 0 Zi H h I 'd'O'0'0'tl'd'd'dro'd'droro'0ro'0 ro'O ro'0 r0 'CJ'CS Oro roO ro T1'0'O'O 90 '011 T1 25 21'0 NH 2' [. R' ON C C C C C C C C C C C C C C C C C C C C C C C C C C C C C C C C C C 0 C C C C C C a IJ O F H a 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 7 ] O. Ci Z F f c a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a 0 0 N Z 0 L4 N 3 IX H U OF h IP Ill O .. e.ve L o p e S -`(R STa KM 8 • ;f • J8 8 • . J8 • 8 P1 i POND1 ?..: . STR1 O1 P2 -.'f'P3 '� '-!i-' POND2 •,, ).44,.. ir slit -•,',- ,.. ,r: ' •• 1, i . , 1,..:• , s 2 • 1'� . - —E —,`C2 ..03TR3 OND3;-_{{I ' : " ID - • , f . J9f. s ,{ _, 04 y ID /.7-'.., •P ON .7'., . 8TR5.. II ID . �~ . . .t..'•:: • OU TEAL L1 'ti: . ..�*••••..e-''''l. 0UTFALL2 '-?•I - •:, �..< D 0 . . . I I I IP ID II DeVe.10reA S -YK STo RM • EPA sort k RES v LTS II . EPA STORM WATER MANAGEMENT MODEL - VERSION 5.0 (Build 5.0.008) II • • Analysis Options • * 4i;**' Flow Units CFS . Flow Routing Method KINWAVE Starting Date JAN-01-2005 00:00:00 . Ending Date JAN-01-2005 06:00:00 Antecedent Dry Days 0.0 . Report Time Step 00:05:00 Routing Time Step 60.00 sec II II Volume Volume Flow Routing Continuity acre-feet Mgallons • * * `•*!+}*{ IIDry Weather Inflow 0.000 0.000 Wet Weather Inflow 0.000 0.000 IIGroundwater Inflow 0.000 0.000 RDII Inflow 0.000 0.000 IIExternal Inflow 28.747 9.368 External Outflow 17.093 5.570 . Surface Flooding 0.000 0.000 Evaporation Loss 0.000 0.000 . Initial Stored Volume 0.000 0.000 Final Stored Volume 11.656 3.798 . Continuity Error (al -0.005 I▪ • Node*Depth*Summary II S Average Maximum Maximum Time of Max Total Total Depth Depth HGL Occurrence Flooding Minutes . Node Type Feet Feet Feet days hr:min acre-in Flooded II J7 JUNCTION 0.00 0.00 4935.00 0 00:00 0 0 J7 JUNCTION 0.00 0.00 4935.00 0 00:00 0 0 J8 JUNCTION 0.00 0.00 4935.00 0 00:00 0 0 . J9 JUNCTION 0.00 0.00 4935.00 0 00:00 0 0 J10 JUNCTION 0.00 0.00 4935.00 0 00:00 0 0 Ill04 JUNCTION 0.33 0.38 4907.83 0 02:11 0 0 05 JUNCTION 0.28 0.35 4864.35 0 02:00 0 0 . 03 JUNCTION 0.39 0.46 4924.01 0 02:14 0 0 02 JUNCTION 0.39 0.46 4926.56 0 02:14 0 0 . 01 JUNCTION 0.13 0.14 4933.59 0 02:29 0 0 OUTFALL1 OUTFALL 5.90 6.00 4831.00 0 00:07 0 0 . OUTFALL2 OUTFALL 0.00 0.00 4831.00 0 00:00 0 0 P0NO1 STORAGE 6.20 7.22 4938.42 0 02:29 0 0 . P0ND2 STORAGE 2.20 3.42 4931.62 0 02:11 0 0 POND3 STORAGE 2.09 2.98 4925.18 0 02:05 0 0 . POND4 STORAGE 4.17 5.11 4881.31 0 02:13 0 0 PONDS STORAGE 1.77 4.12 4870.32 0 01:42 0 0 II Nod• e*Flow*Summary * **************** IIMaximum Maximum Maximum II Inflow Total Time of Max Flooding Time of Max • Inflow Inflow Occurrence Overflow Occurrence • Node Type CFS CFS days hr:min CFS days hr:min IIJ6 JUNCTION 131.28 131.28 0 00:35 0.00 II II SWMM 5 Page 1 MP • • • •S . J7 JUNCTION 37.04 37.04 0 00:40 0.00 . J9 JUNCTION 51.61 51.61 0 00:40 0.00 J9 JUNCTION 106.62 106.62 0 00:35 0.00 • J10 JUNCTION 21.69 21.69 0 00:40 0.00 04 JUNCTION 0.00 26.20 0 02:11 0.00 OS JUNCTION 0.00 35.19 0 02:00 0.00 03 JUNCTION 0.00 26.20 0 02:10 0.00 II 01 JUNCTION 0.00 14.13 0 02:14 0.00 01 JUNCTION 0.00 3.22 0 02:29 0.00 IIOUTFALL1 OUTFALL 0.00 35.19 0 02:00 0.00 OUTFALL2 OUTFALL 0.00 10.17 0 02:13 0.00 IIPOND1 STORAGE 0.00 131.28 0 00:35 0.00 POND2 STORAGE 0.00 37.04 0 00:40 0.00 IIPOND3 STORAGE 0.00 51.61 0 00:40 0.00 POND4 STORAGE 0.00 106.62 0 00:35 0.00 PONDS STORAGE 0.00 21.69 0 00:40 0.00 II • *.......•.*****....... Storage Volume Summary II Average Avg Maximum Max Time of Max Maximum IIVolume Pcnt Volume Pcnt Occurrence Outflow Storage Unit 1000 ft3 Full 1000 ft3 Full days hr:min CFS • POND2 1 293.907 28 357.678 34 0 02:29 3.22 II48.302 10 93.843 20 0 02:11 10.92 POND3 65.279 11 124.392 20 0 02:05 12.08 II POND4 222.022 12 303.436 16 0 02:13 10.17 PONDS 14.314 5 38.777 13 0 01:42 9.14 * » IIOutfall Loading Summary II IIIFlow Avg. Max. Freq. Flow Flow III Outfall Node Pant. CFS CFS III OUTFALL1 98.33 25.96 35.19 OUTFALL2 98.61 9.10 10.17 ll System 98.47 35.05 45.33 II IlLink*Flow*Summary'**III IIMaximum Time of Max Maximum Max/ Max/ Total IIFlow Occurrence Velocity Full Full Minutes Link Type CFS days hr:min ft/sec Flow Depth Surcharged ' P1 DUMMY 131.28 0 00:35 ' P2 DUMMY 37.04 0 00:40 P3 DUMMY 51.61 0 00:40 P4 DUMMY 106.62 0 00:35 PS DUMMY 21.69 0 00:40 Cl CHANNEL 3.22 0 02:30 5.34 0.00 0.02 0' C2 CHANNEL 14.13 0 02:14 6.09 0.00 0.08 C3 CHANNEL 26.20 0 02:11 13.99 0.00 0.06 0, C4 CHANNEL 26.20 0 02:11 19.47 0.00 0.05 0 CS CHANNEL 35.19 0 02:00 20.77 0.00 0.06 0 STR1 DUMMY 3.22 0 02:29 0 • STR2 DUMMY 10.92 0 02:12 STR3 DUMMY 12.08 0 02:05 STR5 DUMMY 9.14 0 01:43 I I SWMM 5 Page 2 I • • • • • str4 DUMMY 10.17 0 02:13 . Routing* * Time ** * Step Summary . Minimum Time Step 60.00 sec Average Time Step 60.00 sec Maximum Time Step 60.00 sec . Percent in Steady State 0.00 Average Iterations per Step : 1.00 . Analysis begun on: Wed Jun 13 07:57:31 2007 Total elapsed time: 00:00:01 ID • SWMMS Page 3 I Da>ae._to f.e.41to o- Yg- ID . 0 lye..-'t.. : .,L-��::„.::,' i E . =a r. .. STR1. 1': 'PON • i- .•� • \' •a .� om •+e, l VA :..t1 D 0 • . • - Lt. — C2\. 03TR3 "POND3.,; �c : rr f _y`, —.. it.i , C3 +ti c•��"':. � •. • +, a t' , : .fig. r -. t +_�- S. �' r. a.s r ! lT 4'i' ;.•. •.+e ,it ." ' •,tr. �� •;PONDS ' , '7 ;'-- /'S t"[ -II •• i—41. •s-,-STR5,:` :r'„zz ,v • a:.. t , ';POND ..r;_ • ':,:. :' I - - - ' str4, -'' �T�•,1-;b • : - , -4-4-,,,..!),:...' OUTFALL2- , ---- IP II ID Dve,apeA I oo-YR srorkM li EPA st,JMM RESULTS I S . . EPA STORM WATER MANAGEMENT MODEL - VERSION 5.0 (Build 5.0.008) ID • * Analysis Options ID Flow Units CFS . Flow Routing Method KINWAVE Starting Date JAN-01-2005 00:00:00 . Ending Date JAN-01-2005 06:00:00 Antecedent Dry Days 0.0 . Report Time Step 00:05:00 Routing Time Step 60.00 sec II . u........**********.««.«« Volume acre-feet Volume Flow Routing Continuity e-feet Mgallons IIDry+Weather Inflow 0.000 0.000 Wet Weather Inflow 0.000 0.000 IIGroundwater Inflow 0.000 0.000 RDII Inflow 0.000 0.000 . External Inflow 96.541 31.459 External Outflow 31.132 10.145 IISurface Flooding 0.000 0.000 Evaporation Loss 0.000 0.000 . Initial Stored Volume 0.000 0.000 Final Stored Volume 65.411 21.315 IIContinuity Error (%) -0.002 *▪ • Node*Depth*Summary **** ***ID ID Average Maximum Maximum Time of Max Total Total Depth Depth HGL Occurrence Flooding Minutes . Node Type Feet Feet Feet days hr:min acre-in Flooded . Jl JUNCTION 0.00 0.00 4935.00 0 00:00 0 0 J2 JUNCTION 0.00 0.00 4935.00 0 00:00 0 0 J3 JUNCTION 0.00 0.00 4935.00 0 00:00 0 0 IDJ4 JUNCTION 0.00 0.00 4935.00 0 00:00 0 0 JS JUNCTION 0.00 0.00 4935.00 0 00:00 0 0 . O4 JUNCTION 0.45 0.50 4907.95 0 02:32 0 0 O5 JUNCTION 0.42 0.47 4864.47 0 02:30 0 0 . O3 JUNCTION 0.54 0.60 4924.15 0 02:40 0 0 O2 JUNCTION 0.54 0.60 4926.70 0 02:39 0 0 . O1 JUNCTION 0.16 0.17 4933.62 0 02:31 0 0 OUTFALL1 OUTFALL 5.92 6.00 4831.00 0 00:06 0 0 . OUTFALL2 OUTFALL 0.00 0.00 4831.00 0 00:00 0 0 POND1 STORAGE 12.10 13.97 4945.17 0 02:30 0 0 IDPOND2 STORAGE 7.01 9.00 4937.20 0 02:39 0 0 POND3 STORAGE 5.56 6.99 9929.19 0 02:25 0 0 li POND4 STORAGE 10.44 12.61 4888.81 0 02:23 0 0 PONDS STORAGE 10.24 13.56 48]9.]6 0 02:26 0 0 II Node*Flow*Summary ll ..««.«..««*...... Maximum Maximum Maximum Lateral Total Time of Max Flooding Time of Max li • Inflow Inflow Occurrence Overflow Occurrence . Node Type CFS CFS days hr:min CFS days hr:min . J1 JUNCTION 385.76 385.76 0 00:40 0.00 li II SWMM 5 Page 1 IP II II J2 JUNCTION 134.05 134.05 0 00:50 0.00 II J3 JUNCTION 189.65 189.65 0 00:45 0.00 11J4 JUNCTION 382.05 382.05 0 00:40 0.00 J5 JUNCTION 91.78 91.78 0 00:45 0.00 04 JUNCTION 0.00 40.66 0 02:32 0.00 11 05 JUNCTION 0.00 57.23 0 02:30 0.00 03 JUNCTION 0.00 40.66 0 02:31 0.00 11 02 JUNCTION 0.00 22.18 0 02:39 0.00 01 JUNCTION 0.00 4.48 0 02:31 0.00 11 OUTFALL1 OUTFALL 0.00 57.23 0 02:31 0.00 OUTFALL2 OUTFALL 0.00 15.98 0 02:24 0.00 , POND1 STORAGE 0.00 385.76 0 00:40 0.00 POND2 STORAGE 0.00 134.05 0 00:50 0.00 11 POND3 STORAGE 0.00 189.65 0 00:45 0.00 POND4 STORAGE 0.00 382.05 0 00:40 0.00 11 PONDS STORAGE 0.00 91.78 0 00:45 0.00 IIaaaa.faaaaaaffaaaafaaa llStorage*Volume*Summary Il Average Avg Maximum Max Time of Max Maximum II Volume Pcnt Volume Pcnt Occurrence Outflow Storage Unit 1000 ft3 Full 1000 ft3 Full days hr:min CFS II POND1 875.451 83 1049.197 100 0 02:30 4.48 II POND2 331.012 71 464.971 100 0 02:39 17.70 POND3 445.394 73 610.416 100 0 02:25 18.50 IIPOND4 967.030 53 1224.155 67 0 02:23 15.98 PONDS 191.316 66 287.928 99 0 02:26 16.57 II • k Loading*Outfall Summary ID falla.oadnaf Suaaary III Flow Avg. Max. Freq. Flow Flow Outfall Node Pcnt. CFS CFS IIIOUTFALL1 98.61 49.47 57.23 OUTFALL2 100.00 14.09 15.98 I ' System 99.31 63.56 73.20 ' a a a.a Link Flow Summary ' ******************** ID Maximum Time of Max Maximum Max/ Max/ Total ' Flow Occurrence Velocity Full Full Minutes Link Type CFS days hr:min ft/sec Flow Depth Surcharged / P1 DUMMY 385.76 0 00:40 II P2 DUMMY 134.05 0 00:50 P3 DUMMY 189.65 0 00:45 ' P4 DUMMY 382.05 0 00:40 PS DUMMY 91.78 0 00:45 ' Cl CHANNEL 4.48 0 02:31 5.96 0.00 0.03 0 C2 CHANNEL 22.18 0 02:40 6.75 0.00 0.10 0 1C3 CHANNEL 40.66 0 02:32 15.82 0.00 0.08 0 C4 CHANNEL 40.66 0 02:32 22.57 0.00 0.06 0 ' C5 CHANNEL 57.23 0 02:31 24.05 0.00 0.08 0 al STR1 DUMMY 4.48 0 02:31 ' STR2 DUMMY 17.70 0 02:39 STR3 DUMMY 18.50 0 02:25 ' STR5 DUMMY 16.57 0 02:26 1 1 SWMM 5 Page 2 I VP • str4 DUMMY 15.98 0 02:24 . ......................... Routing **iime` Step.Summary Minimum Time Step 60.00 sec . Average Time Step 60.00 sec Maximum Time Step 60.00 sec . Percent in Steady State 0.00 Average Iterations per Step : 1.00 . Analysis begun on: Wed Jun 13 07:44:44 2007 Total elapsed time: < 1 sec r S • p S SWMM 5 Page 3 II p p II i �II II IP APPENDIX D 0 DEVELOPED DRAINAGE CALCULATIONS • • • • • • • • • ••• • • • • • • • • • • • • • • ••• IP • DRAINAGE CRITERIA MANUAL (V. 1) RUNOFF • • , TABLE RO-3 • Recommended Percentage Imperviousness Values • Land Use or Percentage r Surface Characteristics Imperviousness . Business: Commercial areas 95 ill Neighborhood areas 85 . Residential: Single-family * Il Multi-unit(detached) 60 . Multi-unit(attached) 75 Half-acre lot or larger 5 Apartments 80 Industrial: Light areas 80 II Heavy areas 90 . Parks, cemeteries 5 Playgrounds 10 Schools 50 . Railroad yard areas 15 Undeveloped Areas: 5 Historic flow analysis 2 . Greenbelts, agricultural 2 5 Off-site flow analysis 45 (when land use not defined) . Streets: Paved 100 Gravel (packed) 40 . Drive and walks 90 . Roofs 90 Lawns, sandy soil 0 . Lawns, clayey soil 0 . *See Figures RO-3 through RO-5 for percentage imperviousness. II II Based in part on the data collected by the District since 1969, an empirical relationship between C and ll the percentage imperviousness for various storm return periods was developed. Thus, values for C can II be determined using the following equations(Urbonas, Guo and Tucker 1990). Ill CA = KA + (1.31P - 1.44i' + 1.135i- 0.12) for CA ≥0, otherwise CA = 0 (RO-6) IIII Cr o = Ku) + (0.8581' - 0.7861' + 0.774i+ 0.04) (RO-7) II ' Ca =(CA +Ca))/2 II II in which: I• I=% imperviousness/100 expressed as a decimal(see Table RO-3) I I 06/2001 RO-9 ' Urban Drainage and Flood Control District DRAINAGE CRITERIA MANUAL (V. 1) RUNOFF ; , CA = Runoff coefficient for Natural Resources Conservation Service (NRCS)Type A soils C8 = Runoff coefficient for NRCS Type B soils • Ce,, = Runoff coefficient for NRCS Type C and D soils • KA =Correction factor for Type A soils defined in Table RO-4 K o = Correction factor for Type C and D soils defined in Table RO-4 TABLE RO-4 • Correction Factors KA and Kell for Use With Equations RO-6 and RO-7 • Storm Return Period • NRCS Soil Type 2-Year 5-Year 10-Year 25-Year 50-Year 100-Year • C and D 0 -0.10i+ 0.11 -0.18i+ 0.21 -0.281+ 0.33 -0.33i+0.40 -0.391+ 0.46 A 0 -0.08i+ 0.09 -0.141+0.17 -0.191+ 0.24 -0.22/+0.28 -0.25i+ 0.32 . • The values for various catchment imperviousnesses and storm return periods are presented graphically in • Figures RO-6 through RO-8, and are tabulated in Table RO-5. These coefficients were developed for the Denver region to work in conjunction with the time of concentration recommendations in Section 2.4. Use Ile• of these coefficients and this procedure outside of the semi-arid climate found in the Denver region may • not be valid. • • See Examples 7.1 and 7.2 that illustrate the Rational method. The use of the Rational method in storm • sewer design is illustrated in Example 6.13 of the STREETS/INLETS/STORM SEWERS chapter. • • • •• • • 06/2001 RO-10 41 Urban Drainage and Flood Control District w 3 .43 e.1 } :apa,s 'r'*e�A #, ' yes� d" - ,' ' d o c, c, y4 it ss& n r 'dFy„a*" rx b: - r ap ct . C J .V. O yy sy '3.,,+-;.'u"i^. : ',� w. 'it y' ,�,: 30 {� '` `' .M£ l ,d by FE _ h 1("y t {r,vne F .Y h p.,, .P4A ✓� r_ :, Y 3,k v,ry*u.4 fi.#' b{� i z { 3 as ��`fi9" Y ?:�;'" 'r X V C N W, # e t v,15,„ *i n}6{ Af w T 3 1 W T 4,,,,,ssvw t., a+ x $)r vtt a a $ sv.,,,,or,, C \ d *Il p ' . #nxt,g r i R a sitr "iynom,iv� . 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(1990), USGS(1986), US EPA(1983), Veenhuis et a1. (1989), Whipple and Hunter(1981), Urbonas(1997) III Type of BMP (1) TSS TP TN 12 TPb BOD Bacteria Grass Buffer LRR: 10-50 0-30 0-10 0-10 N/A N/A N/A EPR 10-20 0-10 0-10 0-10 N/A N/A N/A • Grass Swale LRR: 20-60 0-40 0-30 0-40 N/A N/A N/A 5 EPR 20-40 0-15 0-15 0-20 N/A N/A N/A . Modular Block Porous Pavement LRR: 80-95 65 75-85 98 80 80 N/A EPR 70-90 40-55 ' 10-20 40-80 60-70 N/A N/A Porous Pavement Detention LRR: 8-96 5-92 -130-85 10-98 60-80 60-80 N/A • EPR 70-90 40-55 10-20 40-80 60-70 N/A N/A • Porous Landscape Detention LRR: 8-96 5-92 -100-85 10-98 60-90 60-80 N/A . EPR 70-90 40-55 20-55 50-80 60-80 N/A N/A . Extended Detention Basin LRR: 50-70 10-20 10-20 30-60 75-90 N/A 50-90 . EPR 55-75 45-55 10-20 30-60 55-80 N/A N/A . Constructed Wetland Basin LRR: 40-94 -4-90 21 -29-82 27-94 18 N/A EPR 50-60 40.80 20-50 30-60 40-80 N/A N/A • • Retention Pond LRR: 70-91 0-79 0-80 0-71 9-95 0-69 N/A . EPR 80-90 45-70 20-60 20-60 60-80 N/A N/A . Sand Filter Extended Detention LRR: 8-96 5-92 -129-84 10-98 60-80 60-80 N/A IllEPR 80-90 45-55 35-55 50-80 60-80 60-80 N/A . Constructed Wetland Channel' LRR: 20-60 0-40 0-30 0-40 N/A N/A N/A EPR 30-50 20-40 10-30 20-40 20-40 N/A N/A • (I)LRR Literature reported range, EPR— expected probable range of annual performance by Volume BMPs. • N/A Insufficient data to make an assessment. • *The EPR rates for a Constructed Wetland Channel assume the wetland surface area is equal or greater than 0.5%of . the tributary total impervious area. r • • •• • • 9-1-99 SQ-17 . Urban Drainage and Flood Control District NIP STRUCTURAL BEST MANAGEMENT PRACTICES DRAINAGE CRITERIA MANUAL(V. 3) , . 1.0 GRASS BUFFER (GB) 0 0 1.1 Description Grass buffer(GB)strips are an integral part of the MDCIA land development concept. They are uniformly . graded and densely vegetated areas of turf grass. They require sheet flow to promote filtration, infiltration and settling to reduce runoff pollutants. GBs differ from grass swales as they are designed to • accommodate overland sheet flow rather than concentrated or channelized flow. They can be used to remove larger sediment from runoff off impervious areas. Whenever concentrated runoff occurs, it should be evenly distributed across the width of the buffer via a flow spreader. This may be a porous pavement strip or another type of structure to achieve uniform sheet-flow conditions.GBs can also be combined with riparian zones in treating sheet flows and in stabilizing channel banks adjacent to major drainageways and receiving waters.GBs can be interspersed ' with shrubs and trees to improve their aesthetics and to provide shading. Irrigation in the semi-arid climate of Colorado is required to maintain a healthy and dense grass on the GB to withstand the erosive forces of runoff from impervious areas. 1.2 General Application A GB can be used in residential and commercial areas. They are typically located adjacent to impervious areas. When used, they should be incorporated into site drainage, street drainage, and master drainage planning. Because their effectiveness depends on having an evenly distributed sheet flow over their surface, the size of the contributing area, and the associated volume of runoff have to be limited. Flow can be directly accepted from an impervious area such as from a parking lot and building roofs, provided the flow is distributed uniformly over the strip. GBs provide only marginal pollutant removal and require I � S-2 9-1-99 Urban Drainage and Flood Control District DRAINAGE CRITERIA MANUAL(V. 3) STRUCTURAL BEST MANAGEMENT PRACTICES • • that follow-up structural BMPs be provided. They do, however, help to reduce some of the runoff volume from small storms.ID 1.3 Advantages/Disadvantages 1.3.1 General.The grass and other vegetation provide aesthetically pleasing green space, which can be . incorporated into a development landscaping plan. In addition, their use adds little cost to a development that has to provide open space, and their maintenance should be no different than routine maintenance of the site's landscaping. Eventually,the grass strip next to the spreader or the pavement will have . accumulated sufficient sediment to block runoff.At that point in time, a portion of the GB strip will need . to be removed and replaced. • Grass and trees within these buffer strips can provide wildlife habitat and help reduce runoff through infiltration. If infiltration occurs, it can reduce the size of downstream drainage facilities. Gravel underdrains can be used where soils are not best suited for infiltration and to help keep the GB's surface dry. 1.3.2 Physical Site Suitability. The site, after final grading, should have a uniform slope and be capable of maintaining an even sheet flow throughout without concentrating runoff into shallow swales or rivulets. The allowable tributary area depends on the width, length, and the soils that lay under the GB. • Hydrologic Soil Groups A and B provide the best infiltration capacity, while Soil Groups C and D provide best site stability. The swelling potential of underlying soils should also be taken into account in how the soils may affect adjacent structures and pavement when water is delivered to the grassed areas. 1 Because of the semi-arid nature of Colorado high plains, an irrigated grass cover is required to be effective. 1.3.3 Pollutant Removal. Pollutant removal depends on many factors such as soil permeability, site ' slope, the flow path length along the buffer, the characteristics of drainage area, runoff volumes and velocities, and the type of vegetation. The general pollutant removal of both particulate and soluble pollutants is projected to be low to moderate.GBs rely primarily upon the settling and interception of solids, and to only a minor degree, on biological uptake and runoff infiltration. See Table SQ-6 for estimated range of pollutant removals. 1.4 Design Considerations Design of GBs are based primarily on maintaining sheet-flow conditions across a uniformly graded, ' irrigated, dense grass cover strip. When a GB is used over unstable slopes, soils, or vegetation, ' formation of rills and gullies that disrupt sheet flow will occur. The resultant short-circuiting will invalidate ' the intended water quality benefits.GBs should be protected from excessive pedestrian or vehicular • I ' 9-1-99 S-3 Urban Drainage and Flood Control District 1 S STRUCTURAL BEST MANAGEMENT PRACTICES DRAINAGE CRITERIA MANUAL (V. 3) • traffic that can damage the grass cover and affect even sheet-flow distribution.A mixture of grass and trees may offer benefits for slope stability and improved aesthetics. 1.5 Design Procedure and Criteria The following steps outline the GB design procedure and criteria. Figure GB-1 is a schematic of the facility and its components. 1. Design Discharge Determine the 2-year peak flow rate of the area draining to the GB.Also, determine the flow control type; sheet or concentrated. 2. Minimum Length Calculate the minimum length(normal to flow) of the GB. The upstream flow needs to be uniformly distributed over this length. General guidance suggests that the hydraulic load should not exceed 0.05cfsllinear foot of buffer in the Colorado high plains region during a 2-year storm to maintain a sheet flow of less than 1 inch throughout dense grass that is at least 2 inches high. The minimum design length (normal to flow) is therefore calculated as: °2-year I_(-4 _ 0.05 In which: Lv = Minimum design length (feet) I O2-year = Peak discharge supplied to the GBs by a 2-year event (cfs) ' Longer lengths may be used. 3. Minimum Width The minimum width (W G) (the distance along the sheet flow direction) of the BG shall be determined by the following criteria for onsite and concentrated flow control conditions: A. Sheet Flow Control (use the larger value) WG= 0.2Lt or 8 feet In which: Li = The length of flow path of the sheet flow over the upstream impervious surface(feet) B. Concentrated Flow Control (use the larger value) WG= 0.15(At/Lt) or 8 feet In which: At = The tributary area (square feet) Lt =The length of the tributary (normal to flow) upstream of the GB(feet) The longer the buffer area is relative to the impervious area draining to • it, the smaller the effective imperviousness, per Figure ND-1. J S-4 9-1-99 Urban Drainage and Flood Control District p DRAINAGE CRITERIA MANUAL(V. 3) STRUCTURAL BEST MANAGEMENT PRACTICES • * A generally rectangular shape strip is preferred and should be free of gullies or rills that concentrate the overland flow. 4. Maximum Slope Design slopes shall not exceed 4 percent. 5. Flow Distribution Incorporate a device on the upstream end of the buffer to evenly distribute flows along the design length. Slotted curbing, modular block porous pavement (MBP), or other spreader devices can be used to apply flows. Concentrated flow supplied to the GB must use a level spreader (or a similar concept) to evenly distribute flow onto the buffer. 6. Vegetation Vegetate the GB with irrigated dense turf in semi-arid areas of Colorado to promote sedimentation and entrapment and to protect against erosion. 7. Outflow Collection Provide a means for outflow collection. Most of the runoff during . significant events will riot be infiltrated and will require a collection and conveyance system. A GS can be used for this purpose and can provide another MDCIA type of a BMP.The buffer can also drain to a storm sewer or to a street gutter. 1.6 Design Example Design forms that provide a means of documenting the design procedure are included in the Design Forms section.A completed form follows as a design example. ID • 9-1-99 S-5 . Urban Drainage and Flood Control District W • STRUCTURAL.BEST MANAGEMENT PRACTICES DRAINAGE CRITERIA MANUAL:0/3) • • Buffer Strip Width • • E-- , LI WG>8'or<02Ll • >.-t (whichever is longer) • Dense Grass(irrigation) • Swale • \ Impervious • Area T t' r k • —f k _4, IC T • At =Tributary Area Grass y ____÷ le Buffer _ 14 Strip 65` 4 • --D. Jr —► l 1T k l • 1 g Footer to k y k k Prevent Slumping S • S o • le • 5,3 Di . O 11 1 • Maximum Unit Hydraulic • Loading during 2-year Perforated Drains in • Storm=0.05 cfs/ft Gravel Trenches(optional) • SHEET FLOW CONTROL Buffer Strip Width _ • WG>0.15(At/LI). or>8' Concentrated (whichever is longer) • Flow So<4°% Swale • • 4 • N;.•::\\.., -► __ k k k k • J' A �,. • T Grass y t .\�.'.. Butterli • \.,..\� Strip if • ` T y t • \ ` So -.,...,c-Q6-5,6. �S 1 • • Level Spreader • (other designs include gravel trenches, modular porous pavement,and • stabilized turf strip) • CONCENTRATED FLOW CONTROL • Note:Not to Scale • • • FIGURE GB-1 Applications of Grass Buffers • Ill, . ) • • S-6 9-1-99 • Urban Drainage and Flood Control District • t • STRUCTURAL BEST MANAGEMENT PRACTICES DRAINAGE CRITERIA MANUAL(V.3) • • • 2.0 GRASS SWALE (GS)-SEDIMENTATION FACILITY • • • • A i • y y • • • • • • 2.1 Description • A grass swale (GS) sedimentation facility is an integral part of the MDCIA development concept.They • are densely vegetated drainageways with low-pitched sideslopes that collect and slowly convey runoff. • Design of their longitudinal slope and cross-section size forces the flow to be slow and shallow, thereby • • facilitating sedimentation while limiting erosion. Berms or check dams should be installed perpendicular • to the flow as needed to slow it down and to encourage settling and infiltration. • 2.2 General Application • • A GS can be located to collect overland flows from areas such as parking lots, buildings, residential • yards, roadways and grass buffer strips t3Bs). They can be made a part of the plans to minimize a • directly connected impervious area by using them as an alternative to a curb-and-gutter system.A GS is • set below adjacent ground level, and runoff enters the swales over grassy banks.The potential exists for • wetland vegetation to becometestablished if the swale experiences standing water or if there is a base • flow. If that condition is possible, consider the use of underdrains. A site with a base flow should be • managed as either a swale with an unlined trickle channel, or as a wetland bottom channel, the latter • providing an additional BMP to stormwater runoff. • 2.3 Advantages/Disadvantages • • 2.3.1 General.A GS, which can be more aesthetically pleasing than concrete or rock-lined drainage • systems, is generally less expensive to construct. Although limited by the infiltration capacity of local a soils, this BMP can also provide some reduction in runoff volumes from small storms. Dense grasses can • reduce flow velocities and protect against erosion during larger storm events. Swales in residential and • • commercial settings can also be used to limit the extent of directly connected impervious areas. • • S-8 9-1-99 • Urban Drainage and Flood Control District • p DRAINAGE CRITERIA MANUAL(V. 3) STRUCTURAL BEST MANAGEMENT PRACTICES ▪ • The disadvantages of using GSs without underdrains include the possibility of soggy and wet areas in • front yards, the potential for mosquito breeding areas, and the potential need for more right-of-way than is needed for a storm sewer. • 2.3.2 Physical Site Suitability. A GS is practical only at sites with general ground slopes of less than . 4 percent and are definitely not practical for sites steeper than 6 percent. The longitudinal slopes of a GS . should be kept to less than 1.0 percent,which often necessitates the use of grade control checks or drop structures. Where the general terrain slope exceeds 4 percent, a GS is often practical only on the . upslope side of the adjacent street. . . When soils with high permeability(for example, Class A or B)are available, the swale will infiltrate a • portion of the runoff into the ground, but such soils are not required for effective application of this BMP. . When Class C and D soils are present, the use of a sand/gravel underdrain is recommended. • 2.3.3 Pollutant Removal. Removal rates reported in literature vary and fall into the low to medium range. Under good soil conditions and low flow velocities, moderate removal of suspended solids and associated other constituents can be expected. If soil conditions permit,infiltration can remove low to moderate loads of soluble pollutants when flow velocities are very low. As a result, small frequently • occurring storms can benefit the most. See Table SQ-6 in the Storm water Quality Management chapter • • for estimated ranges in pollutant removal rates by this BMP. • 2.4 Design Considerations and Criteria • Figure GS-1 shows trapezoidal and triangular swale configurations. A GS is sized to maintain a low • velocity during small storms and to collect and convey larger runoff events, all for the projected fully • developed land use conditions. If the design flows are not based on fully developed land conditions,the • swales will be undersized and will not provide the intended pollutant removal, flow attenuation, or flow • conveyance capacity. • A healthy turf grass cover must be developed to foster dense vegetation. Permanent irrigation in some cases may be necessary. Judicious use of GSs can replace both the curb-and-gutter systems and greatly • reduce the storm sewer systems in the upper portions of each watershed when designed to convey the "initial storm"(for example, a 2-or a 5-year storm) at slow velocities. However, if one or both sides of the GS are also to be used as a GB, the design of the GB has to follow the requirements of Section 1. Grass • Buffers. • • • • 9-1-99 S-9 • Urban Drainage and Flood Control District STRUCTURAL BEST MANAGEMENT PRACTICES DRAINAGE CRITERIA MAMt$L (V•. } ▪ • 2,5 Design Procedure and Criteria The following steps outline the GS design procedure and criteria. . 1. Design Discharge Determine the 2-year flow rate in the proposed GS using hydrologic . procedures described in Volume 1 of the USDCM. . 2. Swale Geometry Select geometry for the GS. The cross section should be either trapezoidal or triangular with side slopes flatter than 4:1 (Horizontal/ Vertical), preferably 5:1 or flatter. The wider the wetted area of the swale, the slower the flow. . 3. Longitudinal Slope Maintain a longitudinal slope for the GS between 0.2 and 1.0 percent. If the longitudinal slope requirements can not be satisfied with available terrain,grade control checks or small drop structures must be . incorporated to maintain the required longitudinal slope. If the slope of the swale exceeds 0.5 percent in semi-arid areas of Colorado,the swale must be vegetated with irrigated turf grass. 4. Flow Velocity Calculate the velocity and depth of flow through the swale. Based on . and Depth Mannings equation and a Mannings roughness coefficient of n=0.05,find the channel velocity and depth using the 2-year flow rate determined in Step 1. Maximum flow velocity of the channel shall not exceed 1.5 feet per . second and the maximum flow depth shall not exceed 2 feet at the 2-year peak flow rate. If these conditions are not attained, repeat steps 2 • through 4 each time altering the depth and bottom width or longitudinal slopes until these criteria are satisfied. 5. Vegetation Vegetate the GS with dense turf grass to promote sedimentation, . filtration,and nutrient uptake, and to limit erosion through maintenance of low flow velocities. 6. Street and If applicable, small culverts at each street crossing and/or driveway . Driveway Crossings crossing may be used to provide onsite stormwater capture volume in a . similar fashion to an EDB(if adequate volume is available). 7. Drainage and Check the water surface during larger storms such as the 5-year Flood Control through the 100-year floods to ensure that drainage from these larger . ` events is being handled without flooding critical areas or residential, . commercial, and industrial structures. 2.6 Design Example Design forms that provide a means of documenting the design procedure are included in the Design Forms section. A completed form follows as a design example. ▪ • . S-10 9-1-99 Urban Drainage and Flood Control District . STRUCTURAL BEST MANAGEMENT PRACTICES DRAINAGE CRITERIA MANUAL(V.3) S . . Residual Capacity • for Larger Floods Ill l2-year Flow Note: •. _ Al Underdrain . Depth(D)≤3 Feet fl ment is A_41 ry For Type • V2 yr<2.0 f sN. /Ps • 6'Sandy Loam Turf iuo�� Sideslope: • ti-ti•ti-ti•ti•t•ti•t•ti-t--.-+•ti•ti-ti•ti• Z>4(Z>5 Prefered) 6'ASTMC-33 Sand P}_r.r.r_r.r_r_r_r�r_r.r.rr.r.r-r Underdrain �/ 4'Perforated pipe in 9' i CDOT Sect. 703, • AASHTO#8 Coarse Aggregate • 4 Bottom Width(W) ' • TRAPEZOIDAL GRASS-LINED SWALE SECTION • NOT TO SCALE • Slope=0.2%to 1.0% (drop toe to drop crest) Extend Along Bank to 2-yr Flow • r i /Depth Plus a Minimum of 0.5 Feet • ��;'''� 1 ' n i Grade Control Checks ♦ is V. _ ►��•i�=�.•♦�.�♦� rrrvv�.�.�.� Underdrain GRASS-LINED SWALE PROFILE ��•ivi '� NOT TO SCALE • • Residual Capacity • 2-year Flow -=- • 1 • Note: Depth(D)s 3 Feet Z Underdrain r 2'Min • Necessary ForType V2-yr Q.0 fps I C&D Soils Not Type • Ma Soils _4Sideslope: • Z>4(Z>5 preferred) • 6'Sandy Loam Turf C:1/4,_ • 6'ASTM C-33 Sand 4'Perforated pipe in 9' Underdrain CDOT Sect.703, AASHTO#8 • Coarse Aggregate • TRIANGULAR GRASS-LINED SWALE SECTION • NOT TO SCALE • FIGURE GS-1 • . Profile and Sections of a Grass Swale • • 9-1-99 • Urban Drainage and Flood Control District S-11 p . DRAINAGE CRITERIA MANUAL (V. 3) STRUCTURAL BEST MANAGEMENT PRACTICES ▪ • 5.0 POROUS LANDSCAPE DETENTION (PLD)-SEDIMENTATION FACILITY 1• 0 O . .0 owlesy• nce .,ges my 5.1 Description . Porous landscape detention (PLD) consists of a low lying vegetated area underlain by a sand bed with an underdrain pipe. A shallow surcharge zone exists above the PLD for temporary storage of the WQCV. During a storm,accumulated runoff ponds in the vegetated zone and gradually infiltrates into the underlying sand bed, filling the void spaces of the sand. The underdrain gradually dewaters the sand bed • and discharges the runoff to a nearby channel,swale, or storm sewer. Like PPD,this BMP allows WQCV to be provided on a site that has little open area available for stormwater detention. 5.2 General Application • 5.2.1 Locating. A PLD can be located in just about any of the open areas of a site. It is ideally suited for small installations such as: . • Parking lot islands . • Street medians • Roadside swale features . • Site entrance or buffer features This BMP may also be implemented at a larger scale, serving as an infiltration basin for an entire site if desired provided the water quality capture volume and average depth requirements contained in this section are met. Vegetation may consist of irrigated bluegrass or natural grasses with shrub and tree plantings if desired. 5.2.2 Example Application. The following photos illustrate an installation of PLD in Prince Georges County,Maryland. • 9-1-99 S-27 ' Urban Drainage and Flood Control District U STRUCTURAL BEST MANAGEMENT PRACTICES DRAINAGE CRITERIA MANUAL(Y. $) Parking lot island before installation of PLD '» . i = .` r ar -44*, .ta 'Excavation and installation of underdrain. h } S • ;1 a• diI � — !£r ` Sandy material used as planting medium I •• 4 f ♦`' Photos:Courtesy Prince Georges County . • S-28 9-1-99 ' Urban Drainage and Flood Control District S DRAINAGE CRITERIA MANUAL (V. 3) STRUCTURAL BEST MANAGEMENT PRACTICES S • • > �` Installation of plant materials r - { ¢ect- 7. w4 Completed PLD facility during storm -4-�" s"" event .r • a`: f • • Photos fn rtesy Prance GeoryesCovny . 5.3 Advantages/Disadvantages • 5.3.1 General.A primary advantage of PLD is making it possible to provide WQCV on a site while reducing the impact on developable land- It works well with irrigated bluegrass, whereas experience has shown that conditions in the bottom of extended detention basins (EDBs) become too wet for bluegrass. A PLD provides a natural moisture source for vegetation, enabling reen areas"to exist with reduced irrigation.The adjacent photograph shows an example of a relatively large PLD facility featuring a bluegrass bottom with a putting green. • The primary disadvantage of PLD is a potential for clogging if a moderate to high level of silts and clays is I._ allowed to flow into the facility. Also,this BMP needs to be avoided close to building foundations or other areas _ where expansive soils are present, although an underdrain and impermeable liner can ameliorate some of this concern. — - _ 5.3.2 Physical Site Suitability. If an underdrain system •. is incorporated into this BMP, PLD is suited for about any F 9-1-99 S-29 Urban Drainage and Flood Control District STRUCTURAL BEST MANAGEMENT PRACTICES DRAINAGE CRITERIA MANUAL (V. 3) • • site regardless of in-situ soil type. If sandy soils are present, the facility can be installed without an • underdrain (infiltration option); sandy subsoils is not a requirement. This BMP has a relatively flat surface • area, and may be more difficult to incorporate it into steeply sloping terrain. 5.3.3 Pollutant Removal.Although not tested to date in the Denver area, the amount of pollutant removed by this BMP should be significant and should equal or exceed the removal rates provided by sand filters. In addition to settling, PLD provides for filtering, adsorption, and biological uptake of constituents in stormwater. See Table SQ-6 for estimated ranges in pollutant removals. • 5.4 Design Considerations Figure PLD-1 shows a cross-section for a PLD. When implemented using multiple small installations on a site, it is increasingly important to accurately account for eaeh upstream drainage area tributary to each PLD site to make sure that each facility is properly sized, and that all portions of the development site are directed to a PLD. • 5.5 Design Procedure • The following steps outline the PLD design procedure and criteria. 1. Basin Storage Volume Provide a storage volume based on a 12-hour drain time. A. Find the required storage volume (watershed inches of runoff): • Using the tributary areas imperviousness, determine the Required . WQCV(watershed inches of runoff) using Figure PLD-2, based on the PLD 12-hour drain time. • B. Calculate the Design Volume in cubic feet as follows: • (WQCV Design Volume=ll *Area 12 • In which: . ` Area = The watershed area tributary to the extended . detention pond (square feet) 2. Surface Area Calculate the minimum required surface area as follows: Surface Area = Design Volume in ft3 • da„ in which, d„= average depth of the PLD basin. • 3. Base Coarses Provide base coarses as shown in Figure PLD-1. • 4. Subbase If expansive soils are a concern, install an impermeable membrane and place the base coarse on top of the membrane. If soils are not ▪ • expansive, use geotextile fabric to line the entire basin bottom and walls. S-30 9-1-99 . Urban Drainage and Flood Control District • • DRAINAGE CRITERIA MANUAL (V. 3) STRUCTURAL BEST MANAGEMENT PRACTICES • • • • 5. Average Depth Maintain the average WQCV depth between 6"and 12".Average depth • is defined as water volume divided by the water surface area. • 6. Sand-Peat Mix Provide a minimum of a 12-inch thick layer above the base course . Filter Layer consisting of a thoroughly mixed ASTMC-3 Sand and Peat for filtration and adsorption of constituents. 7. Irrigated Vegetative Provide a sandy loam turf layer above the sand-peat mix layer. This • Layer layer shall be no less than 6-inches thick, but a thicker layer is . recommended to promote healthier vegetation. . 5.6 Design Example ID Design forms that provide a means of documenting the design procedure are included in the Design Forms section.A completed form follows as a design example. ID • S • 9-1-99 S-31 Urban Drainage and Flood Control District . STRUCTURAL BEST MANAGEMENT PRACTICES DRAINAGE CRITERIA MANUAL(V. 3) • ((r OPTIONAL 100 YEAR DETENWOCY ON AT PRIGATED TURF GRASS. . SLOTTED CURB SI ACE TER OTHER P GRASSES.AND SUgFACE OTHER PLANTINGS PAVEMENT . SANDY LOAM Rye TURF LAYER N FLOW A'EII_I THAT, AVERAGE DEPTH A n< T5%AST7mcirs 10]SX PEAT ML _ - 1B'MM! ` . .. ....� alllllll�l♦�.... Lr�_ Q GRAVEL LAYER . KART SECT AG RE ATE) NT COARSE AGGREGATE) IMPERMEABLEFONEXNINE SA . IF ON WISE USE SOILS. OPTIONAL N00.YFAR GEOTEAISE USE DETENTION MOROI GEOTFXiIE LINER . 3 TO A NCH pA PERFORATED PIPE UNDERDRNN CONNECTED TO INLET (MAY BE ELIMINATED F UNDERLAYING . • SOILS ARE SANDY) FIGURE PLD-1 Porous Landscape Detention ▪ w . S-32 9-1-99 Urban Drainage and Flood Control District a STRUCTURAL OEST MANAGEMENT PRACTICES DRAINAGE CRITERIA MANUAL(V.3) • • 10.0 CONSTRUCTED WETLANDS CHANNEL (CWC)- SEDIMENTATION FACILITY 0 • sf r-` • S S 0 , n 10.1 Description Constructed wetland-bottomed channels takes advantage of dense natural vegetation (rushes,willows, cattails, and reeds)to slow down runoff and allow time for settling out sediment and biological uptake. It • is another form of a sedimentation facility and a treatment plant. II, , Constructed wetlands differ from"natural"wetlands as they are artificial and are built to enhance stormwater quality. Sometimes small wetlands that exist along ephemeral drainageways on Colorado's high plains may be enlarged and incorporated into the constructed wetland system. Such action, however, requires the approval of federal and state regulators. 1111 Regulations intended to protect natural wetlands recognize a separate classification of wetlands constructed for a water quality treatment. Such wetlands generally are not allowed to be used to mitigate the loss of natural wetlands but are allowed to be disturbed by maintenance activities. Therefore, the . legal and regulatory status of maintaining a wetland constructed for the primary purpose of water quality enhancement is separate from the disturbance of a natural wetland. Nevertheless,any activity that disturbs a constructed wetland should be first cleared through the U.S. Army Corps of Engineers to ensure it is covered by some form of an individual, general, or nationwide 404 permit. 10.2 General Application Wetland bottom channels can be used in the following two ways: ' • A wetland can be established in a totally man-made channel and can act as a conveyance system and water quality enhancement facility. This design can be used along wide and gently sloping channels. p S-76 9-1-99 Urban Drainage and Flood Control District OP • DRAINAGE CRITERIA MANUAL(V. 3) STRUCTURAL BEST MANAGEMENT PRACTICES • • • • A wetland bottom channel can be located downstream of a stormwater detention facility(water • quality and/or flood control) where a large portion of the sediment load can be removed. The wetland • channel then receives stormwater and base flows as they drain from the detention facility, provides • water quality enhancement, and at the same time conveys it downstream. This application of a • wetland channel is recommended upstream of receiving waters and within lesser(i.e., ephemeral) receiving waters, thereby delivering better quality water to the more significant receiving water • system. . A CWC requires a net influx of water to maintain their vegetation and microorganisms. A complete water budget analysis is necessary to ensure the adequacy of the base flow. . 10.3 Advantages/Disadvantages 10.3.1 General. Constructed wetlands offer several potential advantages, such as natural aesthetic qualities,wildlife habitat, erosion control, and pollutant removal. Constructed wetlands provide an effective follow-up treatment to onsite and source control BMPs that rely upon settling of larger sediment particles. In other words, they offer yet another effective BMP for larger tributary basins. The primary drawback to wetlands is the need for a continuous base flow to ensure their presence. In addition,salts and scum can accumulate and unless properly designed and built, can be flushed out • during larger storms. 111 Other disadvantages include the need for regular maintenance to provide nutrient removal. Regular harvesting and removal of aquatic plants, cattails, and willows is required if the removal of nutrients in significant amounts has to be assured. Even with that, recent data puts into question the net effectiveness of wetlands in removing nitrogen compounds and some form of phosphates. Periodic sediment removal is also necessary to maintain the proper distribution of growth zones and of water movement within the wetland. 10.3.2 Physical Site Suitability.A perennial base flow is needed to sustain a wetland, and should be determined using a water budget analysis. Loamy soils are needed in wetland bottom to permit plants to ' take root. Infiltration through a wetland bottom cannot be relied upon because the bottom is either covered by soils of low permeability or because the groundwater is higher than the wetland's bottom. Wetland bottom channels also require a near-zero longitudinal slope; drop structures are used to create and maintain a flat grade. 10.3.3 Pollutant Removal. Removal efficiencies of constructed wetlands vary significantly. Primary variables influencing removal efficiencies include design, influent concentrations, hydrology, soils, climate, and maintenance. With periodic sediment removal and plant harvesting, expected removal • efficiencies for sediments, organic matter, and metals can be moderate to high;for phosphorous, low to moderate; and for nitrogen, zero to low. Pollutants are removed primarily through sedimentation and 1 9-1-99 S-77 Urban Drainage and Flood Contrd District S1ttUCTURAt-BEST MANAGEMENT PRACTICES DRAINAGE CRITERIA MANUAL(V. 3) I entrapment, with some of the removal occurring through biological uptake by vegetation and microorganisms. Without a continuous dry-weather base flow, salts and algae can concentrate in the water column and can be released into the receiving water in higher levels at the beginning of a storm event as they are washed out. Harvesting aquatic plants and periodic removal of sediment also removes nutrients and pollutants associated with the sediment. Researchers still do not agree that routine aquatic plant harvesting affects . pollutant removals. Until research documents these effects, periodic harvesting for the general upkeep of wetland, and not routine harvesting of aquatic plants, is recommended. • 10.4 Design Considerations - • Wetlands can be set into a drainageway to form a wetland bottom channel(see Figure CWC-1). The criteria for a wetland bottom channel presented in the following section differs somewhat from the criteria presented in Volume 2 of the USDCM under the Major Drainage chapter. This is because of the water quality focus of this BMP. An analysis of the water budget is needed so that the inflow of water throughout the year is sufficient to meet all the projected losses (such as evaporation,evapotranspiration, and seepage).An insufficient base flow could cause the wetland bottom channel to dry out and die. 10.5 Design Procedure and Criteria • • The following steps outline the Constructed Wetlands Channel design procedure. Refer to Figure CWC-1 for its design components. 1. Design Discharge Determine the 2-year peak flow rate in the wetland channel without reducing it for any upstream ponding or flood routing effects. • 2. Channel Geometry Define the newly-built channel geometry to pass the design 2-year flow rate at 2.0 feet per second with a channel depth between 2.0 to 4.0 feet. The channel cross-section should be trapezoidal with side slopes of 4:1 (HorizontalNertical) or flatter. Bottom width shall be no less than 8.0 feet. 3. Longitudinal Slope Set the longitudinal slope using Mannings equation and a Mannings . roughness coefficient of n=0.03, for the 2-year flow rate. If the desired longitudinal slope can not be satisfied with existing terrain, grade control checks or small drop structures must be incorporated to provide desired slope. • 4. Final Channel Capacity Calculate the final (or mature) channel capacity during a 2-year flood using a Mannings roughness coefficient of n=0.08 and the same geometry and slope used when initially designing the channel with . n=0.03. The channel shall also provide enough capacity to contain the flow during a 100-year flood while maintaining one foot of free-board. Adjustment of the channel capacity may be done by increasing the • bottom width of the channel. Minimum bottom width shall be 8 feet. ▪ak • S-78 9-1-99 Urban Drainage and Flood Control District IP STRUCTURAL BEST MANAGEMENT PRACTICES DRAINAGE CRITERIA MANUAL(V. 3) ID • • 5. Drop Structures Drop structures should be designed to satisfy the drop structure criteria of the Major Drainage chapter in Volume 2 of the USDCM. 6. Vegetation Vegetate the channel bottom and side slopes to provide solid . entrapment and biological nutrient uptake. Cover the channel bottom with loamy soils upon which cattails, sedges, and reeds should be established. Side slopes should be planted with native or irrigated turf grasses. 7. Maintenance Access Provide access for maintenance along the channel length. Maximum grades for maintenance vehicles should be 10 percent and provide a solid driving surface. 10.6 Design Example Design forms that provide a means of documenting the design procedure are included in the Design Forms section. A completed form follows as a design example. ID▪ • ▪ • 9-1-99 S-79 Urban Drainage and Flood Control District STR-UCTURAL$EST MANAGEMENT PRACTICES DRAINAGE CRITERIA MANUAL(V.3) O ✓ . 2-year Flood Level Additional Capacity Baseflow Level for Larger Floods S t S 3 ft.Min. Incorporate 9'Layer Bank Toe of VL Riprap into Protection Bank Sods Use Moisture Retaining . SECTION Organic Soils in Bottom NOT TO SCALE (4 to 6 inches deep) . • Baseflow Level . Drop Structure or Check Cattails L . S v y Slope r \Erosion Protection • SECTION NOT TO SCALE S FIGURE CWC-1 Plan and Section of a Constructed Wetland Channel ▪ • S 9-1-99 S-80 Urban Drainage and Flood Control District • • • • DRAINAGE CRITERIA MANUAL (V. 3) CONSTRUCTION BEST MANAGEMENT PRACTICES • • • • . EROSION CONTROL PLAN SYMBOLS • TITLE KEY SYMBOL • CHECK DAM CD ____.4-y,____-i . CONSTRUCTION ROAD CRS STABILIZATION CURB SOCK INLET 0 0 PROTECTION CS TEMPORARY DIVERSION DIKE (DC) O TEMPORARY CHANNEL Dv O DIVERSIONII / \ • STORM DRAIN IP ) INLET PROTECTION l J MULCHING M„ OUTLET PROTECTION OP 's['t f == ` PAVED FLUME PF Pr PERMANENT SEEDING (CO P5 ROUGH CUT STREET CONTROL .® g 2 Figure C-1—Map Symbols • 9-1-99 C-3 Urban Drainage and Flood Control District 1 OP • DRAINAGE CRITERIA MANUAL(V. 3) CONSTRUCTION BEST MANAGEMENT PRACTICES EROSION CONTROL PLAN SYMBOLS TITLE KEY SYMBOL SEDIMENT BASIN SB TEMPORARY STREAM CROSSING SC ,-.. SILT FENCE SF SURFACE ROUGHENING SR Sa • SEDIMENT TRAP ST STRAW BALE BARRIER STB TEMPORARY SEEDING TS iS TEMPORARY SLOPE DRAIN TSD VEHICLE TRACKING CONTROL VTC VEHICLE TRACKING CONTROL WITH WASH RACK \\ J Figure C-1A—Map Symbols(Continued) • C-4 9-1-99 Urban Drainage and Flood Control District III• • • DRAINAGE CRITERIA MANUAL(V. 3) CONSTRUCTION BEST MANAGEMENT PRACTICES S . i 0 • Ms • VEHICLE TRACKING CONTROL • a Definition • A stone stabilized pad located at points of vehicular ingress and egress on a construction II site. II Purposes To reduce the amount of mud transported onto public roads by motor vehicles or runoff. ID Note: Only applicable for sites greater than 2 acres in size S ID /" .• S „,-,- I �- I ID .---" CO - I -- I II ID ,te -..14:, : I : : ::4 • • • • • • • • • • • • iik II 9'Minimum .;:q,•4•.•.•.0.*.*...0.,.•• II VL Riprap(D50=6") *•4$1:::::g:::::.,- 4,z• ll Non-Woven Geotextile Filter Cloth r IFigure C-8--Temporary Vehicle Tracking Control lir II 9-1-99 C-33 II Urban Drainage and Flood Control District • • • DRAINAGE CRITERIA MANUAL (V 3) CONSTRUCTION BEST MANAGEMENT PRACTICES S . • • l ay VEHICLE TRACKING CONTROL ID S S Definition A stone stabilized pad located at points of vehicular ingress and egress on a construction site equipped with a concrete wash rack. . Purposes . To reduce the amount of mud transported onto public roads by motor vehicles or runoff. . Note: Only needed when required by focal City or County of jurisdiction. May be precluded from use if no water supply is available. • VEHICLE TRACKING CONTROL WITH WASH RACK / .w Ditch to carry wash water t0 sediment basin or trap • Wash Rack .c. 1' 6r .I i�� •'ilj:�'ri�', .�`• :: f::•:': N�..may.. � '• '- -.'wt.��= 1 Lr..t'r•.i. ♦i�•r.�—..i...?►�:.�ii:�il�r�Ar%�.��%rl. •i...!..rr.rl Reinforced Concrete Drain Space Detail of Wash Rack From: Virginia soil and Water Conservation Commission, 1985 1 Figure C-8A---Temporary Vehicle Tracking Control With Wash Rack 1 C-34 9-1-99 Urban Drainage and Flood Control District P III Ill Ill DRAINAGE CRITERIA MANUAL (V. 3) CONSTRUCTION BEST MANAGEMENT PRACTICES S . ill . d ri_, r r S1B O STRAW BALE BARRIER 0 0 I . Definition . A temporary sediment barrier consisting of a row of entrenched and anchored straw bales. . Purposes i 1. To intercept and detain small amounts of sediment from disturbed areas of limited exteni in order to reduce segment In runoff from leaving the site. • 2. To decrease the velocity of sheet flows from hillslope areas III IP • Staked and Entrenched Wood or Steel Fence Post Straw Bale (Reber not allowed) • Binding Wire or Twine Compacted Soil to 111 1111 01 Prevent Piping 4 it I Sediment Laden ID Filtered Runoff �� Runoff D I iii J 1H :----..„...--• _� ►ri . t1t1 I IIII lam`I . ., .. �ltu�- lll^--- 4"11 i Min. i �1 I llui �t��-- f ID _ II - I ._._ 1 � 111 ,'' 12" Min. From: Virginia Soil and Water Conservation Commission, 1985 ' Figure C-12—Staw Bale Barriers 1 1 , 1 ' C-42 9-1-99 Urban Drainage and Flood Control District 1 1 ID . DRAINAGE CRITERIA MANUAL(V. 3) CONSTRUCTION BEST MANAGEMENT PRACTICES • • . '� �� •i + 1, I I f _ Bale r ..... d liYt Rowidth - --0_.4.;,----s'; i 4 !.` . r� l 0 Ill Ill .cr•• - ID • l s �K�•�'s ��1 `',4 _"---4''' •-•:-_;.-..:.-: � 1+1��+�ii• 3. Wedge loose straw between 4. Backfili and compact the . bales. excavated soil. . . 0 From:Virginia Soil and Water Conservation Commission, 1985 • . Figure C-12A—Staw Bale Barrier Installation ID Ill el Ill • • • 9-1-99 C-43 Urban Drainage and Flood Control District • 0 DRAINAGE CRITERIA MANUAL(V. 3) CONSTRUCTION BEST MANAGEMENT PRACTICES pac ( SF'; . ett -SHIT,EN� -q lestleisteva- .4 Virsits44 WSW 4 4a h a . ils a f J ,�� bMfyp(f�"�' Ff ` II k.I f �t } • SILT FENCE INSTALLATION NTS- . . • FABRIC MATERIAL STEEL OR 2x4"WOOD POST z/ (ACHORED IN TRENCH) (ANCHORED TO FABRIC) -\ . _ . -- 4"x4''TRENCH a _COMPACTED BACKFILL NOTE'.EROSION CONTROL MEASURES ' `:v,.• l/ FLOW SHALL BE MAINTAINED UNTIL s A.* LANDSCAPING IS COMPLETED, 1/2H(12"MIN) ` OR AS DIRECTED BY LOCAL • JURISDICTION I _.. i4 SECTION DETAIL SILT FENCE EROSION BARRIER Details provided to District by the City of Broomfield,Colorado Figure C-13—Silt Fence Erosion Barrier • C-44 9-1-99 Urban Drainage and Flood Control District ID I� it ID DRAINAGE CRITERIA MANUAL(V. 3) CONSTRUCTION BEST MANAGEMENT PRACTICES 0 • ID II ID s:zszzsgies=lz:z SB ID TEMPORARY SEDIMENT BASIN S 0 ID Definitions A temporary basin with a controlled stormwater release structure,formed by excavation or construction of an embankment of compacted soil. Required for all drainage areas greater than 1 area. ID ID Purposes ID To detain sediment-laden runoff from distributed areas to allow the majority of the sediment to settle out. II ID Required volume to crest of emergency Limiting Geometry: spillway= 1800 cubic feet per acre of 0 , UW greater than 2.0 drainage area. Should be cleaned out prior to becoming half full. ID 100-Year or Larger Emergency Spillway ---0.9,003---- .0 I Emergency ':.'„..., acSFoa�po cNtrdYnonstructed i� .:Y ,`,�-t•.ter �.yi.�7�•.; S =1. T- O o O .-J..Y -': X41':{ •:'':.1 1R •,•t over fill _., "": • material - ,,� `.r� � ��',..af �:�.�.,� ..�2V : `�-:tea:��•'^Kf•J?L.-." �,_ it C ,,; 1` i TfNFj(ar.�S..v,.3 j j2tt; ...t' r - r• �{iiiLi • ffi. I I I From: Virginia Soil and Water Conservation Commission, 1985 Figure C-15--Teporary Sediment Basin I I . 1 ' 9-1-99 C-47 ' Urban Drainage and Flood Control District I • • DRAINAGE CRITERIA MANUAL(V. 3) CONSTRUCTION BEST MANAGEMENT PRACTICES . SEDIMENT CLEANOUT LEVEL (SWEAT OF LOWEST ORIFICE. Al 50%Of ST %A iE VOLUME) . 100 YR(OR LARGER( -8'(OR LARGER)PVC PERFORATED 100 SPILLWAY CREST(BEYOND) RISER PIPE(PERFORATIONS SIZED (SHALL BE PROTECTED WITHRWMP) . TO VFW..VOLUME BELOW EMERGENCY SPILLWAY IN 40 HOURS) BASIN EM BANRME N1 JCR FLALIER I' ]OR A FLATTER RIPRAP T os / APRON 05%l LARGER)PVC OUTLET PIPE Ir 90(OK RGERI PVC 0.5%MIN SLOPE 90'ELBOW Figure C-15A—Temporary Sediment Basin Outlet Detail r S S S S S S S p p p II p p Ill • ' C-48 9-1-99 Wban Drainage and Flood Control District r p I • DRAINAGE CRITERIA MANUAL (V. 3) CONSTRUCTION BEST MANAGEMENT PRACTICES• ii Ill SI• D Inflow--DP- . �C8 Riser (outlet) • Ii� • Normal Pool • Le = total distance from li the point of Inflow around the baffle to II j the riser. IP Normal Poolill '1.1 (; - g---- � Riser 13— III \ b — — Baffle '_ N. D -_ —IP I • • Riser Inflow IP Normal Pool L e= t + L 2 I ' •*-L2 Inflow I Sheets of 4'x8'x1/2" exterior 6" IP 7- plywood or equivalent — - Riser Crest Elevation II fl Ii 4' II 1 4 I: !: I •r-- Posts min. size 4" . It I' Ill1 'I square or 5" round. Set It 41 at least 3' into the ground. I From: Environmental Protection Agency, 1976 I I Figure C-16—Temporary Sediment Basin Outlet Detail 1 I II Ai 1 ' 9-1-99 C-49 Urban Drainage and Flood Control District U S . DRAINAGE CRITERIA MANUAL(V. 3) CONSTRUCTION BEST MANAGEMENT PRACTICES SO - See Figures 4 and 5 in the TYPICAL DETAILS section to determine the appropriate • perforation geometry(Note: Although Figures 4 and 5 are based on a flat orifice plate, the • resulting hole sizes and patterns may be applied to the cylindrical riser pipe.). The outlet pipe(8-inch or larger PVC)shall extend through the embankment at a minimum slope . of 0.5%. A riprap apron shall be provided at the outfall. A baffle should be constructed to protect the outlet and improve sedimentation in the basin if the length-to-width ratio is less than 2 to 1 (D • to D/2)for various geometry's to provide Le greater than or equal to D as shown in Figure C-16. . • Maintenance: The basin shall be dredged out prior to the design storage volume becoming half filled with sediment. 1 C-50 9-1-99 Urban Drainage and Flood Control District O DRAINAGE CRITERIA MANUAL (V- 3) CONSTRUCTION BEST MANAGEMENT PRACTICES • OP OUTLET PROTECTION 0 Definition Structurally lined aprons or other acceptable energy dissipating devices placed at the outlets O of pipes or paved channel sections. . Purposes To prevent scour at stormwater outlets and to minimize the potential for downstream erosion . by reducing the velocity of concentrated stormwater flows. Extend riprap to height of culvert or normal . channel depth, whichever is smaller Riprap thickness on channel side slopes . egua! to 1.5d50 • •::sue. • • 3:1 maximum • Downstream Channel • 4 - PLAN . L Conduit or Paved Outlet Channel Concrete cradle/cut off, lL or standard headwall 1.5d50 End slope at 1:1 2d M � 2d 50 O U2 Granular Bedding PROFILE . See Urban Storm Drainage Criteria Manual, Vol. 2, "Major Drainage", Section 5.6 for design criteria. • From: Urban Drainage and Flood Control District, 1961 Figure C-20—Outlet Protection for a Culvert in a Channel ▪ i 9-1-99 C-59 Urban Drainage and Flood Control District U S DRAINAGE CRITERIA MANUAL(V. 3) CONSTRUCTION BEST MANAGEMENT PRACTICES 0 �-- �- CD CHECK DAM 0 Definition Small temporary darn constructed across a swale or drainage ditch. Purposes To reduce the velocity of stormwater flows and erosion of the swale or ditch. . ROCK CHECK DAM 24' 0 • 4- to 6- Inch Rods 2r w,p 24° Flow "der L = The distance such that points . A and B are of equal elevation. A L _ - 1 ,, SPACING BETWEEN CHECK DAMS 1 From: Virginia Soil and Water Conservation Commission, 1985 . Figure C-21—Check Dam 0 • C-60 9-1-99 Urban Drainage and Flood Control District iii . DRAINAGE CRITERIA MANUAL (V. 3) CONSTRUCTION BEST MANAGEMENT PRACTICES IID • ill Ill � I P • INLET PROTECTION S ID • Definition • A sediment filter or an excavated impounding area around a storm drain drop inlet or curb inlet. O Purposes . To reduce sediment from entering storm drainage systems prior to permanent stabilization of . disturbed areas. . Drop Inlet with Grate Compacted Soil Staked . - to Prevent Piping Straw Bale ma ci O VAI4;7:1; _ a 0• LI -- ---7_:__—.--- Filtered • o ca with Sediment Water ti i • Straw Bales — Staked with 2 Stakces Per Bale 0 . Specific Application This method of inlet protection is applicable where the inlet drains a relatively flat area . (slopes no greater than 5 percent) where sheet or overland flows (not exceeding 0.5 cfs) are typical. The method shall not apply to inlets receiving concentrated flows, . such as in street or highway medians. • STRAW BALE DROP INLET SEDIMENT FILTER • From: Virginia Soil and Water Conservation Commission, 1985 0 Figure C-22—inlet Protection—Straw Bales 0 0 . C-62 9-1-99 Urban Drainage and Flood Control District • • DRAINAGE CRITERIA MANUAL (V. 3) CONSTRUCTION BEST MANAGEMENT PRACTICES • • • IP • • INLET PROTECTION • • • Definition • A sediment filter or an excavated impounding area around a storm drain drop inlet or curb • inlet. • Purposes • To reduce sediment from entering storm drainage systems prior to permanent stabdIization of disturbed areas. • • Drop Inlet with Grate • �f! _Stakes • Y )' 111 Stakes jf • •;. . ;;may '•c t�� • Fitter Fabric Fabric • Water Filtered Water Sediment • Washed Gravel • • • 8. -- ----- 12M Buried Filter Fabric . 8M • • From: Washington State Department of Ecology, 1991 • • Figure C-23—Inlet Protection—Filter Fabric • • • • 9-1-99 C-63 Urban Drainage and Flood Control District • • 0 • DRAINAGE CRITERIA MANUAL(V. 3) CONSTRUCTION BEST MANAGEMENT PRACTICES S . Ill ID ID I 0 5 J/--INLET W/CURB OPENING WIRE _ . 7x4"WOOD STUD SCREEN 6'\ A / - EXTENDED INTO ��___.., CONC_BLOCKS • / -T��' 4 h}'gg43T' Po.YW�gC.C'3W.<}'•H:f5 Z•:P'Atiti4A'DA\L.SS.[Y �' \\ s K�r3a. sap ix ae-r `YV ? < CONCRETE 5 A BLOCKS ROCK FILTER MATERIAL , (3/4"GRAVEL)PLACED NEXT . TO CONCRETE BLOCKS TRAFFIC CONES REQUIRED 5 ON PAVED OR TRAVELED - - SURFACES 5 S . OVERFLOW --CONCRETE END BLOCKS WIRE SCREEN- . ROCK FILTER MATERIAL--- FLOW,ID ..� F4 ic :Itc;,: Illc&flr ' . • PAVEMENT- CONCRETE 5 BLOCKS -- •- INLET 5 7x4"WOOD STUD- -_- < SECTION A-A . . .. -NTS- -Ill �� NOTE'EROSION CONTROL MEASURES SHALL 5 BE MAINTAINED AT ALL TIMES AS DIRECTED BY THE LOCAL JURISDICTION ID DETAIL ID CURB INLET GRAVEL FILTER Details provided to District by the City of Broomfield,Colorado I Figure C-24—Curb Inlet Gravel Filter 111 ID�• C-64 9-1-99 ID Urban Drainage and Flood Control District I I lk . DRAINAGE CRITERIA MANUAL (V. 3) CONSTRUCTION BEST MANAGEMENT PRACTICES rj I P • INLET PROTECTION O • Definition . A segment filter or an excavated impounding area around a storm drain drop inlet or curb inlet. Purposes 0 To reduce sediment from entering storm drainage systems prior to permanent stabRization of . disturbed areas. . Wire Screen Concrete Block i. - •�� 1•411,12;:',,;..____ • _ice" • .. •• • l N•'. 'iDiv !.: -� Gravel Fitter _ _ --. -_- . (Use graded gravel with 1.5" max. aggregate size) • Wire Screen Filtered Water Overflow Runoff Water with..j ::�.t^.. Sediment -:'�=•%'•�'• ' •.- . - .:/ ..s' tom! s, •��,�,s.�. t; lSill= ► '+IP; Drop Inlet Sediment • with Grate . From:Virginia Soil and Water Conservation Commission, 1985 • Figure C-25—Drop Inlet Protection—Block and Gravel Filter ▪ID 9-1-99 C-65 Urban Drainage and flood Control District ID Ill Ill . DRAINAGE CRITERIA MANUAL(V. 3) CONSTRUCTION BEST MANAGEMENT PRACTICES S. ID Ae tP .) • INLET PROTECTION ID 5 Definition I A sediment filter or an excavated impounding area around a storm drain drop inlet or curb . inlet. Ill Purposes Ill To reduce sediment from entering storm drainage system prior to permanent stabilization of . disturbed areas. Flow��1��`;It•„.fi.�.,• Row '' 1.,.\.*St.•%•%:•• ,:>.*'' .< ''',."..4-C-.i• gA.....,f11. ID /i--------,N:' _. sue;. �'�� i._ • • Flow,,�'i'sy �Flow i 'N�---'::,.....s.- `' ID Sediment-Laden Runoff • - . (� As Depth Below Top of Inlet III ' Required` Min. 1' - Max. 2' -_._--- _ - Max. Slope(�f 2:;: S: 11. ,. 1;.i 11.1' ;:!'�rp— . SLarge orm Water u i- HHoles 4•i l •=• `' Large ParOutticles Settle Out RemovedV for De ;ni;1— Waterin . Drain Inlet --- ID L.-MOW II - - Specific Application • This method of inlet protection is applicable where heavy flows are expected . and where an overflow capability and ease of maintenance are desirable. . From: Virginia Soil and Water Conservation Commission, 1985 • Figure C-26--Drop Inlet Protection—Excavated Drop Inlet Sediment Trap ID ID ID C-66 9-1-99 I Urban Drainage and Flood Control District ID III III . DRAINAGE CRITERIA MANUAL(V. 3) CONSTRUCTION BEST MANAGEMENT PRACTICES 0 0 C I % o EI S 4.0 A. OR �- -: •ice, • 44 Cr • \_ 3/4-inch gravel ..-- 'e _ . 3/4-inch gravel r0A 1/4-Inch mesh 0 _or h mesh or burlap V ' / burlap or Detail 1 • • • A • ao- • ,1' . •• ,,,,,,,,-.7. .,, F;y INLET ,dui ' s •, • x IP eOO mtn O • Detail 2 • NOTES • 1) Socks will be used upgradient of inlet perpendicular to and flush with curb. • 2) No less than two 10-inch diameter socks must be used in sequence,spaced no more than five feet apart,upgradient of inlet. No less than six socks shall be used if the 4-inch sock • size is chosen. • 3) Inchne at 30 degrees from perpendicular,opposite the direction of flow(see Detail 2). • 4) Erosion control measures shall be maintained at all times as directed by the local jurisdiction. • Details based on those provided to District by City of Lakewood,Colorado • • Figure C-27—Inlet Protection—Curb Sock • • • • 9-1-99 C-67 . Urban Drainage and Flood Control District • • • Drainage Report Contains Oversized Maps • - Drainage Plan Historic (Sheet 1 ) - Drainage Plan Overall (Sheet 2) - Drainage Plan Sub Basins (Sheets 3-11 ) See Originals in File • Hello