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HomeMy WebLinkAboutRequest for Zoning Info (2) s ANDERSON ENGINEERING of Minnesota,LLC CIVIL ENGINEERING & LAND SURVEYING 13605 1st Avenue North,Suite 100 • Plymouth, Minnesota 55441 • Tel:763.412.4000 • Fax: 763.412.4090 June 18, 2009 RECEIVED JUL 0 6 2009 Ms. Melanie Curtis Via Email: mcurtis@ci.orono.mn.us C�TYOFORONO Planning &Zoning Coordinator City of Orono P.O. Box 66 Crystal Bay, MN 55323 RE: 2687 Wayzata Boulevard— Response to Comments Orono Building—Spensa Development AELLC Project 11586 Dear Ms. Curtis: We are writing in response to the comments provided by Darren Amundsen of Bonestroo for the grading and stormwater management plan dated May 19, 2009 for parking lot expansion and rain garden at 2687 Wayzata Boulevard. Responses by Anderson Engineering (AE) directly follow each comment. Bonestroo: Concrete curb and gutter should be installed around the perimeter of the parking lot. AE: Per June 8th on-site meeting, it was concluded that this is a private parking area and surface water sheet drains to rain garden; therefore, no curb is necessary. Bonestroo: The discharge rates for the rain garden (4.63 cfs 10-year and 6.79 cfs 100- year event) exceed those of the existing conditions(2.96 cfs 10-year and 4.50 cfs 100- year event). All runoff rates for proposed conditions should be less than or equal to existing condition rates. AE: Rain garden area/size has been adjusted and post run-off rates are less than or equal to pre run- off rates. Revised summary stormwater report. Bonestroo: Geotechnical reports for the adjacent Crystal Bay Business Center indicated that parking lot pavement sections include a 12-inch select granular, 6-inch aggregate base,and 3-inch bituminous pavement section for normal duty pavement. Heavy duty pavement(drive lanes of the parking lot) was to have 24-inches select granular,8-inches of aggregate base,and 4-inches of bituminous. We would recommend using these pavement sections or have the applicant submit a geotechnical report stating that the 6- inch aggregate base and 2.5-inch bituminous is sufficient. AE: Private parking areas maintain 3"section and private drive aisle was increased to 3% " pavement section per on site discussion with Tom Kellogg. Z:\Docs 11 500\1 1586 Orono Bldg-Spensa\Response to Comments 6-18-09.doc Orono Building—Spensa Page 2 of 3 Response to Comments June 18,2009 Bonestroo: Draintile should be provided for the rain garden. AE: Updated plans and details to reflect 6"draintile in rain garden. Bonestroo: The applicable code section is 79-7(c)(2)for all commercial or industrial sites in which land disturbance activities fill or excavate more than 100 cubic yards. AE Plans and narratives were revised to meet code. Sonestroo: To bring this submittal in to compliance with the ordinance,the following information should be provided separately or on the grading plan. Phasing plan. A phasing plan shall be provided that clearly indicates the areas in the order they are to be disturbed and restored. The phasing plan shall consider minimization of area and duration of exposed soil and unstable conditions, minimization of the disturbance of natural soil cover and vegetation,erosion and sediment control measure installation,weather conditions and the schedule for temporary and permanent restoration.The area and duration of each phase shall be indicated on the plan. AE: Phasing plan sequencing has been added to the grading plan. Standard detail sheet. A standard detail sheet shall be provided that consists of applicable construction details for approved erosion and sediment control measures as developed by the City. Other techniques may be used upon prior approval by the City with details provided by the designer. AE: Standard details are shown on Grading/Site Plan and Erosion Control Plan. Specifications. Written specifications for land disturbance activities such as product descriptions, installation and maintenance procedures required by the applicant to carry out the project in accordance with this Chapter. AE: Written narrative is provided on Grading Plan via SWPPP Notes and Procedures. Temporary erosion and sediment control plan: Indicate the location of perimeter controls, construction fence,temporary sedimentation basins, inlet protection, areas to be seeded,areas to be mulched or blanketed, location of construction waste control (dumpsters,chemical storage,concrete washout, portable restroom facilities, etc.)and all other required temporary erosion and sediment control measures. This plan shall also indicate staging of temporary erosion control measures. AE: Added Temporary Erosion Control Plan. Narrative and notes dictate appropriate sequencing and staging for temporary erosion measures. ZADocs 11 500\1 1586 Orono Bldg-Spensa\Response to Comments 6-18-09.doc + Orono Building—Spensa Page 3 of 3 Response to Comments June 18,2009 Permanent erosion and sediment control plan: Indicates areas to be seeded and sodded, sediment ponds,storm sewer systems and all other required permanent erosion and sediment control measures. Permanent storm water pollution controls including, but not limited to ponds,vegetated buffers and structural measures shall be designed and constructed in accordance with other Chapters of the City Code and requirements of other agencies having jurisdiction. AE:Added Permanent Permit Erosion Control Plan. Narrative and notes dictate appropriate sequencing and staging for permanent erosion measures. Narrative: Describes,at a minimum,the nature of construction activity, person(s) responsible for inspection and maintenance of site erosion and sediment control including contact information, project phasing,schedules,along with the timing, installation and maintenance of erosion and sediment control measures and specifications necessary to carry out the project. AE: Narrative added on Grading and Phasing Plan. The$2,000 financial guarantee identified in Section 79-7(b)(2) should be sufficient for this project. AE: Owner to provide. Please feel free contact me with any questions. My direct dial is 763.412.4017 or mbrandvold@ae-mn.com. Sincerely, Anderson Engineering of Minnesota, LLC Michael B. Brandvold, P.E. Enclosure: c Roger Anderson, Anderson Engineering of MN, LLC Greg Engel, Spensa Development Darren Amundsen, PE, Bonestroo ZADocs 11500\11586 Orono Bldg-Spensa\Response to Comments 6-18-09.doc Storm Water Management Plan Calculations & Summaries SPENSA DEY. GROUP Orono, MN Project No. 11586 June 18, 2009 Prepared By: Prepared For: Anderson Engineering of Minnesota, LLC Spensa Dev Group 13605 1St Avenue North, Suite 100 Minnetonka, MN 55305 Plymouth, MN 55441 Ph. 763 412-4000 Fax 763 412-4090 Spensa Dev. Group Proj No. 11586 - June 18, 2009 2687 Wayzata Blvd, Orono, MN STORM WATER COMPARISON Volume Summary ac-ft ac-ft 2-(2.8") 0.16 0.03 1021.6 10-(4.2') 0.29 0.05 1022.5 100-(6.0'7 0.45 0.201 1023.3 Rate Summary cfs cfs 2-(2.8") 2.74 0.50 10-(4.2") 4.68 0.76 100- 6.0" 7.17 5.15 ZADocs 11 500\1 1586 Orono Bldg-Spensa\DRAINAGE\6-17-09 SWMP\6-18-09 RUNOFF Comparison.xls n x (U.S.MGHFAY NO.12)A. . seeroi a2-- u�.w PNae ro g p 50' ___w AY A D SNpY fEKC EASDAINT b lM.r4u : e PER 8001(]!l,POE 2M DOG _—�� _________u_JNAIEA T . . 4 -------- -------------- -------------- ---------- 1 1 � ------------ _ ; I -- --,-,-, ----- `11 i - _ _ I I� II , ;I ------------- I ---- «a - --------------- ---------- Go — - r I it I I O a 1 IDai •T , I bel r I ? 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' a - e�o , 1 M GW-Well-graded gravels, sandy gravels Gravel, sandy gravel and GP— Gap-graded or uniform gravels, sandy 1.63 silty gravels gravels A GM-Silty gravels, silty sandy gravels SW-Well-graded,gravelly sands 0.8 Sand, loamy sand or sandy SP - Gap-graded or uniform sands, gravelly loam sands B0.6 Silt loam SM-Silty sands, silty gravelly sands 0.3 Loam MH — Micaceous silts, diatomaceous silts, volcanic ash C 0.2 Sandy clay loam ML-Silts, very fine sands, silty or clayey fine sands GC—Clayey gravels, clayey sandy gravels SC—Clayey sands, clayey gravelly sands D <0.2 Clay loam, silty clay loam, CL—Low plasticity clays, sandy or silty clays sandy clay, silty clay or clay OL—Organic silts and clays of low plasticity CH—Highly plastic clays and sandy clays OH—Organic silts and clays of high plasticity "Thirty guidance manuals and many other stormwater references were reviewed to compile recommended infiltration rates. All of these sources use the following studies as the basis for their recommended infiltration rates: Rawls,Brakensiek and Saxton(1982); Rawls,Gimenez and Grossman(1998); Bouwer and Rice (1989);and Urban Hydrology for Small Watersheds(NRCS). The rates presented in this infiltration table use the information compiled from these sources as well as eight years of infiltration rates collected in various infiltration practices located in the Twin Cities metropolitan area. levels of runoff. Care must also be taken when numbers appropriate to AMC II. However, if the selecting curve numbers for agricultural land as its specific conditions of interest are expected to use can change considerably annually and even differ, curve numbers appropriate to AMC I or III over the course of a season. should be used. IAntecedent Moisture Conditions Antecedent moisture conditions (AMC) describe Infiltration Rates the moisture already present in the soil at the Infiltration is the process of water entering the time of the rain event. AMC level I represents dry soil matrix. The rate of infiltration depends on conditions, level II represents normal conditions, soil properties, vegetation, and the slope of the and level III represents wet conditions. Normal surface, among other factors. Discussions of conditions are defined as 1.4 to 2.1 inches of infiltration often include a discussion of hydraulic rainfall in the growing season in the five days conductivity. Hydraulic conductivity is a measure preceding the event of interest. Most evaluations of ease with which a fluid flows through the soil, of expected future site conditions use the curve but it is not the infiltration rate. The infiltration rate tame N S. WAaolmm or wmvurv. P0"sm R • .-.`",W`"L'"�'.�.��.. 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PHASING, GRADING, aua..Aa Pw aauKc C /J >r a.N AaaL.aa w r...a.r r SPENSA DEVELOPMENT GROUP, LLC UTILITY do DETAIL PLAN 1 OF 2 X:\11500\11586 Spensa 0rono\dwg\11586S1TE.dwg,1:65.0688 EXISTING PROPOSED EXISTING PROPO ED NG POND 1 Subcat Reach on Llnk Drainage Diagram for 11586 SPENSA-ORONO-revised 5-28-09 Prepared by{enter your company name here} 6/17/2009 HydroCAD®8.00 s/n 000837 ©2006 HydroCAD Software Solutions LLC 11586 SPENSA - ORONO -revised 5-28-09 Prepared by{enter your company name here} Page 2 HydroCAD®8.00 s/n 000837 ©2006 HvdroCAD Software Solutions LLC 6/17/2009 Area Listing (all nodes) Area (acres) CN Description (subcats) 0.278 61 >75% Grass cover, Good, HSG B (1 P,1 P,1 P,1 X,1 X) 0.684 85 Gravel roads, HSG B (1 P,1 P,1 X,1 X,2X) 0.278 98 Building (1P,1X) 1.018 98 Paved parking & roofs (1P,1X,2P,2X) 2.259 11586 SPENSA - ORONO -revised 5-28-09 Type 1124-hr 2 yr Rainfall=2.80" Prepared by{enter your company name here} Page 3 HydroCADO 8.00 s/n 000837 ©2006 HydroCAD Software Solutions LLC 6/17/2009 Time span=4.00-27.00 hrs, dt=0.05 hrs, 461 points Runoff by SCS TR-20 method, UH=SCS Reach routing by Stor-Ind+Trans method - Pond routing by Stor-Ind method Subcatchment 1P: PROPOSED RunoffArea=42,540 sf Runoff Depth=1.64" Tc=10.0 min CN=88 Runoff=2.41 cfs 0.134 of Subcatchment 1X: EXISTING Runoff Area=42,590 sf Runoff Depth=1.64" Tc=12.0 min CN=88 Runoff=2.27 cfs 0.134 of Subcatchment 2P: PROPOSED Runoff Area=6,630 sf Runoff Depth>2.54" Tc=11.0 min CN=98 Runoff=0.50 cfs 0.032 of Subcatchment 2X: EXISTING Runoff Area=6,630 sf Runoff Depth>2.35" Tc=12.0 min CN=96 Runoff=0.47 cfs 0.030 of Pond RAIN G: POND 1 Peak Elev=1,021.56' Storage=3,996 cf Inflow=2.41 cfs 0.134 of Discarded=0.05 cfs 0.059 of Primary=0.00 cfs 0.000 of Outflow=0.05 cfs 0.059 of Total Runoff Area=2.259 ac Runoff Volume=0.329 of Average Runoff Depth = 1.75" 42.62% Pervious Area=0.963 ac 57.38% Impervious Area= 1.296 ac 11586 SPENSA- ORONO -revised 5-28-09 Type 11 24-hr 2 yr Rainfall=2.80" Prepared by(enter your company name here) Page 4 HydroCAD®8.00 s/n 000837 ©2006 HydroCAD Software Solutions LLC 6/17/2009 Subcatchment 1 P: PROPOSED Runoff = 2.41 cfs @ 12.01 hrs, Volume= 0.134 af, Depth= 1.64" Runoff by SCS TR-20 method, UH=SCS, Time Span=4.00-27.00 hrs, dt=0.05 hrs Type II 24-hr 2 yr Rainfall=2.80" Area (sf) CN Description 1,590 61 >75% Grass cover, Good, HSG B 190 61 >75% Grass cover, Good, HSG B 6,420 61 >75% Grass cover, Good, HSG B 7,240 85 Gravel roads, HSG B 580 85 Gravel roads, HSG B 20,460 98 Paved parking &roofs 6,060 98 Building 42,540 88 Weighted Average 16,020 Pervious Area 26,520 Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 10.0 Direct Entry, Typical Inspection Subcatchment 1X: EXISTING Runoff = 2.27 cfs @ 12.04 hrs, Volume= 0.134 af, Depth= 1.64" Runoff by SCS TR-20 method, UH=SCS, Time Span=4.00-27.00 hrs, dt=0.05 hrs Type II 24-hr 2 yr Rainfall=2.80" Area (sf) CN Description 1,590 61 >75% Grass cover, Good, HSG B 2,340 61 >75% Grass cover, Good, HSG B 7,240 85 Gravel roads, HSG B 13,600 85 Gravel roads, HSG B 11,760 98 Paved parking & roofs 6,060 98 Building 42,590 88 Weighted Average 24,770 Pervious Area 17,820 Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 12.0 Direct Entry,Typical Inspection 11586 SPENSA - ORONO -revised 5-28-09 Type 1124-hr 2 yr Rainfall=2.80" Prepared by{enter your company name here} Page 5 HydroCADO 8.00 s/n 000837 ©2006 HydroCAD Software Solutions LLC 6/17/2009 Subcatchment 213: PROPOSED Runoff = 0.50 cfs @ 12.02 hrs, Volume= 0.032 af, Depth> 2.54" Runoff by SCS TR-20 method, UH=SCS, Time Span=4.00-27.00 hrs, dt= 0.05 hrs Type II 24-hr 2 yr Rainfall=2.80" Area (sf) CN Description 6,630 98 Paved parking & roofs 6,630 Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 11.0 Direct Entry, Typical Inspection Subcatchment 2X: EXISTING Runoff = 0.47 cfs @ 12.03 hrs, Volume= 0.030 af, Depth> 2.35" Runoff by SCS TR-20 method, UH=SCS, Time Span=4.00-27.00 hrs, dt= 0.05 hrs Type II 24-hr 2 yr Rainfall=2.80" Area (sf) CN Description 1,140 85 Gravel roads, HSG B 5,490 98 Paved parking & roofs 6,630 96 Weighted Average 1,140 Pervious Area 5,490 Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 12.0 Direct Entry,Typical Inspection Pond RAIN G: POND 1 Inflow Area = 0.977 ac, Inflow Depth = 1.64" for 2 yr event Inflow = 2.41 cfs @ 12.01 hrs, Volume= 0.134 of Outflow = 0.05 cfs @ 17.54 hrs, Volume= 0.059 af, Atten= 98%, Lag= 331.9 min Discarded = 0.05 cfs @ 17.54 hrs, Volume= 0.059 of Primary = 0.00 cfs @ 4.00 hrs, Volume= 0.000 of Routing by Stor-Ind method, Time Span=4.00-27.00 hrs, dt= 0.05 hrs Peak Elev= 1,021.56' @ 17.54 hrs Surf.Area= 3,331 sf Storage= 3,996 cf Plug-Flow detention time=436.1 min calculated for 0.059 of(44% of inflow) Center-of-Mass det. time= 316.2 min ( 1,137.5 - 821.3 ) 11586 SPENSA- ORONO -revised 5-28-09 Type 11 24-hr 2 yr Rainfall=2.80" Prepared by{enter your company name here} Page 6 HydroCAD®8.00 s/n 000837 ©2006 HydroCAD Software Solutions LLC 6/17/2009 Volume Invert Avail.Storage Storage Description #1 1,019.50' 7,760 cf Custom Stage Data (Prismatic) Listed below(Recalc) Elevation Surf.Area Inc.Store Cum.Store (feet) (sq-ft) (cubic-feet) (cubic-feet) 1,019.50 610 0 0 1,020.00 1,233 461 461 1,021.00 2,557 1,895 2,356 1,022.00 3,947 3,252 5,608 1,022.50 4,660 2,152 7,760 Device Routing Invert Outlet Devices #1 Discarded 0.00' 0.600 in/hr Exfiltration over Horizontal area #2 Primary 1,022.50' 2.0' long x 5.0' breadth Broad-Crested Rectangular Weir Head (feet) 0.20 0.40 0.60 0.80 1.00 1.20 1.40 1.60 1.80 2.00 2.50 3.00 3.50 4.00 4.50 5.00 5.50 Coef. (English) 2.34 2.50 2.70 2.68 2.68 2.66 2.65 2.65 2.65 2.65 2.67 2.66 2.68 2.70 2.74 2.79 2.88 Qiscarded OutFlow Max=0.05 cfs @ 17.54 hrs HW=1,021.56' (Free Discharge) 1=Exfiltration (Exfiltration Controls 0.05 cfs) Primary OutFlow Max=0.00 cfs @ 4.00 hrs HW=1,019.50' (Free Discharge) t2=Broad-Crested Rectangular Weir ( Controls 0.00 cfs) 11586 SPENSA- ORONO -revised 5-28-09 Type 11 24-hr 10 yr Rainfall=4.20" Prepared by{enter your company name here} Page 7 HydroCADO 8.00 s/n 000837 0 2006 HydroCAD Software Solutions LLC 6/17/2009 Time span=4.00-27.00 hrs, dt=0.05 hrs, 461 points Runoff by SCS TR-20 method, UH=SCS Reach routing by Stor-Ind+Trans method - Pond routing by Stor-Ind method Subcatchment 1P: PROPOSED Runoff Area=42,540 sf Runoff Depth=2.92" Tc=10.0 min CN=88 Runoff=4.20 cfs 0.237 of Subcatchment 1X: EXISTING Runoff Area=42,590 sf Runoff Depth=2.92" Tc=12.0 min CN=88 Runoff=3.95 cfs 0.238 of Subcatchment 2P: PROPOSED Runoff Area=6,630 sf Runoff Depth>3.90" Tc=11.0 min CN=98 Runoff=0.76 cfs 0.049 of Subcatchment 2X: EXISTING Runoff Area=6,630 sf Runoff Depth>3.72" Tc=12.0 min CN=96 Runoff=0.73 cfs 0.047 of Pond RAIN G: POND 1 Peak Elev=1,022.46' Storage=7,591 cf Inflow=4.20 cfs 0.237 of Discarded=0.06 cfs 0.084 of Primary=0.00 cfs 0.000 of Outflow=0.06 cfs 0.084 of Total Runoff Area=2.259 ac Runoff Volume=0.571 of Average Runoff Depth=3.04" 42.62% Pervious Area=0.963 ac 57.38%Impervious Area= 1.296 ac 11586 SPENSA- ORONO -revised 5-28-09 Type //24-hr 10 yr Rainfall=4.20" Prepared by{enter your company name here} Page 8 HydroCAD®8.00 s/n 000837 0 2006 HydroCAD Software Solutions LLC 6/17/2009 Subcatchment 1 P: PROPOSED Runoff = 4.20 cfs @ 12.01 hrs, Volume= 0.237 af, Depth= 2.92" Runoff by SCS TR-20 method, UH=SCS, Time Span=4.00-27.00 hrs, dt= 0.05 hrs Type II 24-hr 10 yr Rainfall=4.20" Area (sf) CN Description 1,590 61 >75% Grass cover, Good, HSG B 190 61 >75% Grass cover, Good, HSG B 6,420 61 >75% Grass cover, Good, HSG B 7,240 85 Gravel roads, HSG B 580 85 Gravel roads, HSG B 20,460 98 Paved parking & roofs 6,060 98 Building 42,540 88 Weighted Average 16,020 Pervious Area 26,520 Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 10.0 Direct Entry, Typical Inspection Subcatchment 1X: EXISTING Runoff = 3.95 cfs @ 12.04 hrs, Volume= 0.238 af, Depth= 2.92" Runoff by SCS TR-20 method, UH=SCS, Time Span=4.00-27.00 hrs, dt= 0.05 hrs Type II 24-hr 10 yr Rainfall=4.20" Area (sf) CN Description 1,590 61 >75% Grass cover, Good, HSG B 2,340 61 >75% Grass cover, Good, HSG B 7,240 85 Gravel roads, HSG B 13,600 85 Gravel roads, HSG B 11,760 98 Paved parking & roofs 6,060 98 Building 42,590 88 Weighted Average 24,770 Pervious Area 17,820 Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 12.0 Direct Entry, Typical Inspection 11586 SPENSA- ORONO -revised 5-28-09 Type 11 24-hr 10 yr Rainfall=4.20" Prepared by{enter your company name here} Page 9 HydroCADO 8.00 s/n 000837 ©2006 HvdroCAD Software Solutions LLC 6/17/2009 Subcatchment 213: PROPOSED Runoff = 0.76 cfs @ 12.02 hrs, Volume= 0.049 af, Depth> 3.90" Runoff by SCS TR-20 method, UH=SCS, Time Span=4.00-27.00 hrs, dt= 0.05 hrs Type II 24-hr 10 yr Rainfall=4.20" Area (sf) CN Description 6,630 98 Paved parking & roofs 6,630 Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 11.0 Direct Entry, Typical Inspection Subcatchment 2X: EXISTING Runoff = 0.73 cfs @ 12.03 hrs, Volume= 0.047 af, Depth> 3.72" Runoff by SCS TR-20 method, UH=SCS, Time Span=4.00-27.00 hrs, dt= 0.05 hrs Type II 24-hr 10 yr Rainfall=4.20" Area (sf) CN Description 1,140 85 Gravel roads, HSG B 5,490 98 Paved parking & roofs 6,630 96 Weighted Average 1,140 Pervious Area 5,490 Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 12.0 Direct Entry, Typical Inspection Pond RAIN G: POND 1 Inflow Area = 0.977 ac, Inflow Depth = 2.92" for 10 yr event Inflow = 4.20 cfs @ 12.01 hrs, Volume= 0.237 of Outflow = 0.06 cfs @ 18.67 hrs, Volume= 0.084 af, Atten= 98%, Lag= 399.3 min Discarded = 0.06 cfs @ 18.67 hrs, Volume= 0.084 of Primary = 0.00 cfs @ 4.00 hrs, Volume= 0.000 of Routing by Stor-Ind method, Time Span=4.00-27.00 hrs, dt= 0.05 hrs Peak Elev= 1,022.46' @ 18.67 hrs Surf.Area=4,608 sf Storage= 7,591 cf Plug-Flow detention time= 448.3 min calculated for 0.084 of(35% of inflow) Center-of-Mass det. time= 321.8 min ( 1,126.7- 804.9) 11586 SPENSA- ORONO -revised 5-28-09 Type 11 24-hr 10 yr Rainfall=4.20" Prepared by (enter your company name here) Page 10 HydroCAD®8.00 s/n 000837 0 2006 HydroCAD Software Solutions LLC 6/17/2009 Volume Invert Avail.Storage Storage Description #1 1,019.50' 7,760 cf Custom Stage Data(Prismatic) Listed below (Recalc) Elevation Surf.Area Inc.Store Cum.Store (feet) (sq-ft) (cubic-feet) (cubic-feet) 1,019.50 610 0 0 1,020.00 1,233 461 461 1,021.00 2,557 1,895 2,356 1,022.00 3,947 3,252 5,608 1,022.50 4,660 2,152 7,760 Device Routing Invert Outlet Devices #1 Discarded 0.00' 0.600 in/hr Exfiltration over Horizontal area #2 Primary 1,022.50' 2.0' long x 5.0' breadth Broad-Crested Rectangular Weir Head (feet) 0.20 0.40 0.60 0.80 1.00 1.20 1.40 1.60 1.80 2.00 2.50 3.00 3.50 4.00 4.50 5.00 5.50 Coef. (English) 2.34 2.50 2.70 2.68 2.68 2.66 2.65 2.65 2.65 2.65 2.67 2.66 2.68 2.70 2.74 2.79 2.88 Qiscarded OutFlow Max=0.06 cfs @ 18.67 hrs HW=1,022.46' (Free Discharge) 1=Exfiltration (Exfiltration Controls 0.06 cfs) Primary OutFlow Max=0.00 cfs @ 4.00 hrs HW=1,019.50' (Free Discharge) t2=Broad-Crested Rectangular Weir ( Controls 0.00 cfs) 11586 SPENSA-ORONO -revised 5-28-09 Type 1124-hr 100 yr Rainfall=6.00" Prepared by{enter your company name here} Page 11 HydroCADS 8.00 s/n 000837 ©2006 HydroCAD Software Solutions LLC 6/17/2009 Time span=4.00-27.00 hrs, dt=0.05 hrs, 461 points Runoff by SCS TR-20 method, UH=SCS Reach routing by Stor-Ind+Trans method - Pond routing by Stor-Ind method Subcatchment 1 P: PROPOSED Runoff Area=42,540 sf Runoff Depth>4.63" Tc=10.0 min CN=88 Runoff=6.50 cfs 0.376 of Subcatchment 1X: EXISTING Runoff Area=42,590 sf Runoff Depth>4.63" Tc=12.0 min CN=88 Runoff=6.12 cfs 0.377 of Subcatchment 2P: PROPOSED Runoff Area=6,630 sf Runoff Depth>5.64" Tc=11.0 min CN=98 Runoff=1.10 cfs 0.072 of Subcatchment 2X: EXISTING Runoff Area=6,630 sf Runoff Depth>5.47" Tc=12.0 min CN=96 Runoff=1.05 cfs 0.069 of Pond RAIN G: POND 1 Peak Elev=1,023.34' Storage=7,760 cf Inflow=6.50 cfs 0.376 of Discarded=0.06 cfs 0.090 of Primary=4.05 cfs 0.123 of Outflow=4.11 cfs 0.213 of Total Runoff Area=2.259 ac Runoff Volume=0.894 of Average Runoff Depth =4.75" 42.62% Pervious Area=0.963 ac 57.38%Impervious Area= 1.296 ac I 11586 SPENSA - ORONO -revised 5-28-09 Type 1124-hr 100 yr Rainfall=6.00" Prepared by{enter your company name here) Page 12 HydroCAD®8.00 s/n 000837 ©2006 HvdroCAD Software Solutions LLC 6/17/2009 Subcatchment 1 P: PROPOSED Runoff = 6.50 cfs @ 12.01 hrs, Volume= 0.376 af, Depth> 4.63" Runoff by SCS TR-20 method, UH=SCS, Time Span=4.00-27.00 hrs, dt=0.05 hrs Type II 24-hr 100 yr Rainfall=6.00" Area (sf) CN Description 1,590 61 >75% Grass cover, Good, HSG B 190 61 >75% Grass cover, Good, HSG B 6,420 61 >75% Grass cover, Good, HSG B 7,240 85 Gravel roads, HSG B 580 85 Gravel roads, HSG B 20,460 98 Paved parking & roofs 6,060 98 Building 42,540 88 Weighted Average 16,020 Pervious Area 26,520 Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 10.0 Direct Entry,Typical Inspection Subcatchment 1X: EXISTING Runoff = 6.12 cfs @ 12.03 hrs, Volume= 0.377 af, Depth> 4.63" Runoff by SCS TR-20 method, UH=SCS, Time Span=4.00-27.00 hrs, dt= 0.05 hrs Type II 24-hr 100 yr Rainfall=6.00" Area (sf) CN Description 1,590 61 >75% Grass cover, Good, HSG B 2,340 61 >75% Grass cover, Good, HSG B 7,240 85 Gravel roads, HSG B 13,600 85 Gravel roads, HSG B 11,760 98 Paved parking & roofs 6,060 98 Building 42,590 88 Weighted Average 24,770 Pervious Area 17,820 Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 12.0 Direct Entry,Typical Inspection 11586 SPENSA -ORONO -revised 5-28-09 Type 1124-hr 100 yr Rainfall=6.00" Prepared by{enter your company name here} Page 13 HydroCADO 8.00 s/n 000837 ©2006 HydroCAD Software Solutions LLC 6/17/2009 Subcatchment 2P: PROPOSED Runoff = 1.10 cfs @ 12.02 hrs, Volume= 0.072 af, Depth> 5.64" Runoff by SCS TR-20 method, UH=SCS, Time Span=4.00-27.00 hrs, dt=0.05 hrs Type II 24-hr 100 yr Rainfall=6.00" Area (sf) CN Description 6,630 98 Paved parking & roofs 6,630 Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 11.0 Direct Entry,Typical Inspection Subcatchment 2X: EXISTING Runoff = 1.05 cfs @ 12.03 hrs, Volume= 0.069 af, Depth> 5.47" Runoff by SCS TR-20 method, UH=SCS, Time Span=4.00-27.00 hrs, dt= 0.05 hrs Type II 24-hr 100 yr Rainfall=6.00" Area (sf) CN Description 1,140 85 Gravel roads, HSG B 5,490 98 Paved parking & roofs 6,630 96 Weighted Average 1,140 Pervious Area 5,490 Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 12.0 Direct Entry, Typical Inspection Pond RAIN G: POND 1 Inflow Area = 0.977 ac, Inflow Depth > 4.63" for 100 yr event Inflow = 6.50 cfs @ 12.01 hrs, Volume= 0.376 of Outflow = 4.11 cfs @ 12.13 hrs, Volume= 0.213 af, Atten= 37%, Lag= 7.5 min Discarded = 0.06 cfs @ 12.10 hrs, Volume= 0.090 of Primary = 4.05 cfs @ 12.13 hrs, Volume= 0.123 of Routing by Stor-Ind method, Time Span=4.00-27.00 hrs, dt= 0.05 hrs Peak Elev= 1,023.34' @ 12.13 hrs Surf.Area=4,660 sf Storage= 7,760 cf Plug-Flow detention time= 249.3 min calculated for 0.213 of(57% of inflow) Center-of-Mass det. time= 141.4 min ( 933.4- 792.0) 11586 SPENSA- ORONO -revised 5-28-09 Type 1124-hr 100 yr Rainfall=6.00" Prepared by{enter your company name here} Page 14 HydroCAD®8.00 s/n 000837 ©2006 HydroCAD Software Solutions LLC 6/17/2009 Volume Invert Avail.Storage Storage Description #1 1,019.50' 7,760 cf Custom Stage Data(Prismatic) Listed below (Recalc) Elevation Surf.Area Inc.Store Cum.Store (feet) (sq-ft) (cubic-feet) (cubic-feet) 1,019.50 610 0 0 1,020.00 1,233 461 461 1,021.00 2,557 1,895 2,356 1,022.00 3,947 3,252 5,608 1,022.50 4,660 2,152 7,760 Device Routing Invert Outlet Devices #1 Discarded 0.00' 0.600 in/hr Exfiltration over Horizontal area #2 Primary 1,022.50' 2.0' long x 5.0' breadth Broad-Crested Rectangular Weir Head (feet) 0.20 0.40 0.60 0.80 1.00 1.20 1.40 1.60 1.80 2.00 2.50 3.00 3.50 4.00 4.50 5.00 5.50 Coef. (English) 2.34 2.50 2.70 2.68 2.68 2.66 2.65 2.65 2.65 2.65 2.67 2.66 2.68 2.70 2.74 2.79 2.88 Qiscarded OutFlow Max=0.06 cfs @ 12.10 hrs HW=1,023.19' (Free Discharge) 1=Exfiltration (Exfiltration Controls 0.06 cfs) Primary OutFlow Max=3.61 cfs @ 12.13 hrs HW=1,023.27' (Free Discharge) 't2=Broad-Crested Rectangular Weir (Weir Controls 3.61 cfs @ 2.35 fps)