EROSION CONTROL NARRATIVE

Transcription

1 EROSION CONTROL NARRATIVE Erosion and sediment control has been designed for the Willow Bend Phase I Subdivision according to UDFCD and the City of Thornton criteria, in order to minimize erosion and sediment movement. This Erosion Control plan has been divided into four (4) phases; Initial, Interim, Final A and Final B. The initial phase will take place before construction activities begin on the site. The purpose of this phase will be to set up perimeter control construction best management practices (CBMP). This phase will consist of CBMPs such as silt fence, vehicle tracking control, concrete washout areas, stabilized staging areas, drainage swales/diversion ditches, and temporary sediment basins. These CBMPs will ensure proper sediment and erosion control as construction activities commence within the site. This phase will stay as is in the release plans dated June 12, After the Initial Phase erosion control CBMPs have been established, the Interim Erosion Control phase will begin. During this phase, construction activities such as clearing, grading, utility and infrastructure placement will begin. Rough cut street control will be in place during this phase once overlot grading is completed. In addition, as part of this phase, a temporary detention pond will be put in place, additional to the two sediment basins. All the Erosion Control design calculations for the temporary detention pond 0, sediment basin 1 and 2, as well as the temporary Diversion Ditch and swale have been included with this submittal. A basin map showing the tributary areas going into each of the sediment basins has been included in the report (see map SBTM). The percentage of imperviousness used to design the temporary detention pond 0 is 40% per the Residential % Imperviousness calculations, attached in this report. Diversion Ditch section EC A-A (see construction plans) has been sized for cfs which is the proposed flow from design points 22, 25, 30, and 27 (see Drainage Map). Drainage Swale section EC C-C (see construction plans) has been sized for cfs which is the sum of flows from proposed basins A- 23, A-24, A-25, A-26, A-27, and A-28 (see Drainage Map). Temporary Detention Pond 0 has been sized to required volume of 173, c.f. of storage (3.987 acre-feet), and the spillway weir has been designed for 167 cfs inflow, per the StormCAD results. Temporary Sediment Basin 1 and Sediment Basin 2, have been sized per UDFCD s sediment basin specifications of 3,600 cf/ac. Temporary Detention Pond 0 was designed with a temporary outlet structure as part of the roads draining to this pond will be paved before the Floodplain permit is granted. Sediment Basins 1 was designed to release the design volume through a 5 Floating Skimmer in no less than 48 hours per UDFCD s Sediment Basin Chapter 7, Volume 3. Sediment Basin 2 was designed as a standard sediment basin, using the SB-1 table in the above mention UDFCD chapter for a basin of 15 acres. This sediment basin will release through a riser pipe per the SB-1 table. The outlet structure, floating skimmer and riser pipe were designed in conformance with City of Thornton Standards and Specifications, UDFCD and State requirements. These CBMPs will ensure proper sediment and erosion control as construction activities commence within the site. The Final A phase will take place after the overlot grading has been completed. The Final A Phase will consists of the final stabilization of part of the site (see construction plans, paving area), including CBMPs such as surface roughening, mulching, permanent seeding, and inlet protection. While keeping previous CBMPs such as silt fence, and drainage swales/ditches. The Temporary Detention Pond 0 and the two Sediment Basins will remain during this phase. Final B phase will take place once the Floodplain permit has been issued and permanent stormwater facilities have been constructed, the temporary detention pond and sediment basins can be removed. As inlets/outlets are constructed, inlet/outlet protection will be placed. Final B phase will consists of the

2 final stabilization for the whole site, including CBMPs such as surface roughening, mulching, permanent seeding, and inlet protection. Applicable CBMPs will be kept in place until construction has been completed and final stabilization is complete. This phase will stay as is in the release plans dated June 12, 2017, called Final Erosion Control plans.

3 DETENTION BASIN STAGE-STORAGE TABLE BUILDER Project: Willow Bend 1 UD-Detention, Version 3.07 (February 2017) Basin ID: Temporary Detention Pond 0 Depth Increment = ft Optional Optional Example Zone Configuration (Retention Pond) Stage - Storage Stage Override Length Width Area Override Area Volume Volume Description (ft) Stage (ft) (ft) (ft) (ft^2) Area (ft^2) (acre) (ft^3) (ac-ft) Required Volume Calculation Top of Micropool Selected BMP Type = EDB , , Watershed Area = acres , , Watershed Length = 3,218 ft , , Watershed Slope = ft/ft , , Watershed Imperviousness = 40.00% percent , , Percentage Hydrologic Soil Group A = 0.0% percent , , Percentage Hydrologic Soil Group B = 0.0% percent , , Percentage Hydrologic Soil Groups C/D = 100.0% percent , , Desired WQCV Drain Time = 40.0 hours , , Location for 1-hr Rainfall Depths = Thornton - Civic Center Water Quality Capture Volume (WQCV) = acre-feet Optional User Override Excess Urban Runoff Volume (EURV) = acre-feet 1-hr Precipitation 2-yr Runoff Volume (P1 = 0.97 in.) = acre-feet 0.97 inches 5-yr Runoff Volume (P1 = 1.38 in.) = acre-feet 1.38 inches 10-yr Runoff Volume (P1 = 1.37 in.) = acre-feet inches 25-yr Runoff Volume (P1 = 1.77 in.) = acre-feet inches 50-yr Runoff Volume (P1 = 2.1 in.) = acre-feet inches 100-yr Runoff Volume (P1 = 2.69 in.) = acre-feet 2.69 inches 500-yr Runoff Volume (P1 = 3.4 in.) = acre-feet inches Approximate 2-yr Detention Volume = acre-feet Approximate 5-yr Detention Volume = acre-feet Approximate 10-yr Detention Volume = acre-feet Approximate 25-yr Detention Volume = acre-feet Approximate 50-yr Detention Volume = acre-feet Approximate 100-yr Detention Volume = acre-feet Stage-Storage Calculation Zone 1 Volume (WQCV) = acre-feet Zone 2 Volume (EURV- Zone 1) = acre-feet Zone 3 Volume (100-year - Zones 1 & 2) = acre-feet Total Detention Basin Volume = acre-feet Initial Surcharge Volume (ISV) = user ft^3 Initial Surcharge Depth (ISD) = user ft Total Available Detention Depth (H total) = user ft Depth of Trickle Channel (H TC) = user ft Slope of Trickle Channel (S TC) = user ft/ft Slopes of Main Basin Sides (S main) = user H:V Basin Length-to-Width Ratio (R L/W) = user Initial Surcharge Area (A ISV) = user ft^2 Surcharge Volume Length (L ISV) = user ft Surcharge Volume Width (W ISV) = user ft Depth of Basin Floor (H FLOOR) = user ft Length of Basin Floor (L FLOOR) = user ft Width of Basin Floor (W FLOOR) = user ft Area of Basin Floor (A FLOOR) = user ft^2 Volume of Basin Floor (V FLOOR) = user ft^3 Depth of Main Basin (H MAIN) = user ft Length of Main Basin (L MAIN) = user ft Width of Main Basin (W MAIN) = user ft Area of Main Basin (A MAIN) = user ft^2 Volume of Main Basin (V MAIN) = user ft^3 Calculated Total Basin Volume (V total) = user acre-feet UD-Detention_v3.07-Sediment Pond 0.xlsm, Basin 5/23/2018, 12:33 PM

4 DETENTION BASIN STAGE-STORAGE TABLE BUILDER UD-Detention, Version 3.07 (February 2017) User Defined Stage-Area Boolean for Message 1 Equal Stage-Area Inputs Watershed L:W 1 CountA 0 Calc_S_TC H_FLOOR L_FLOOR_OTHER Length, Width (ft.) ISV 0.00 ISV 0.00 Floor 0.00 Floor 1.97 Zone 1 (WQCV) 1.97 Zone 1 (WQCV) 3.26 Zone 2 (EURV) 3.26 Zone 2 (EURV) 200 Area (sq.ft.) 5.57 Zone 3 (100-year 5.57 Zone 3 (100-year) Stage (ft) Length (ft) Width (ft) Area (sq.ft.) Area (acres) Volume (ac-ft) Stage (ft.) Area (acres) Volume (ac-ft) UD-Detention_v3.07-Sediment Pond 0.xlsm, Basin 5/23/2018, 12:33 PM

5 Detention Basin Outlet Structure Design Project: Willow Bend 1 Basin ID: Temporary Detention Pond 0 UD-Detention, Version 3.07 (February 2017) Stage (ft) Zone Volume (ac-ft) Outlet Type Zone 1 (WQCV) Orifice Plate Zone 2 (EURV) Orifice Plate Zone 3 (100-year) Weir&Pipe (Restrict) Example Zone Configuration (Retention Pond) Total User Input: Orifice at Underdrain Outlet (typically used to drain WQCV in a Filtration BMP) Calculated Parameters for Underdrain Underdrain Orifice Invert Depth = N/A ft (distance below the filtration media surface) Underdrain Orifice Area = N/A ft 2 Underdrain Orifice Diameter = N/A inches Underdrain Orifice Centroid = N/A feet User Input: Orifice Plate with one or more orifices or Elliptical Slot Weir (typically used to drain WQCV and/or EURV in a sedimentation BMP) Calculated Parameters for Plate Invert of Lowest Orifice = 0.00 ft (relative to basin bottom at Stage = 0 ft) WQ Orifice Area per Row = 1.806E-02 ft 2 Depth at top of Zone using Orifice Plate = 3.26 ft (relative to basin bottom at Stage = 0 ft) Elliptical Half-Width = N/A feet Orifice Plate: Orifice Vertical Spacing = N/A inches Elliptical Slot Centroid = N/A feet Orifice Plate: Orifice Area per Row = 2.60 sq. inches (diameter = 1-13/16 inches) Elliptical Slot Area = N/A ft 2 User Input: Stage and Total Area of Each Orifice Row (numbered from lowest to highest) Row 1 (required) Row 2 (optional) Row 3 (optional) Row 4 (optional) Row 5 (optional) Row 6 (optional) Row 7 (optional) Row 8 (optional) Stage of Orifice Centroid (ft) Orifice Area (sq. inches) Row 9 (optional) Stage of Orifice Centroid (ft) 2.74 Orifice Area (sq. inches) 2.60 Row 10 (optional) Row 11 (optional) Row 12 (optional) Row 13 (optional) Row 14 (optional) Row 15 (optional) Row 16 (optional) User Input: Vertical Orifice (Circular or Rectangular) Calculated Parameters for Vertical Orifice Not Selected Not Selected Not Selected Not Selected Invert of Vertical Orifice = N/A N/A ft (relative to basin bottom at Stage = 0 ft) Vertical Orifice Area = N/A N/A ft 2 Depth at top of Zone using Vertical Orifice = N/A N/A ft (relative to basin bottom at Stage = 0 ft) Vertical Orifice Centroid = N/A N/A feet Vertical Orifice Diameter = N/A N/A inches User Input: Overflow Weir (Dropbox) and Grate (Flat or Sloped) Calculated Parameters for Overflow Weir Zone 3 Weir Not Selected Zone 3 Weir Not Selected Overflow Weir Front Edge Height, Ho = 4.50 N/A ft (relative to basin bottom at Stage = 0 ft) Height of Grate Upper Edge, H t = 4.50 N/A feet Overflow Weir Front Edge Length = 5.67 N/A feet Over Flow Weir Slope Length = 2.92 N/A feet Overflow Weir Slope = 0.00 N/A H:V (enter zero for flat grate) Grate Open Area / 100-yr Orifice Area = 3.23 N/A should be > 4 Horiz. Length of Weir Sides = 2.92 N/A feet Overflow Grate Open Area w/o Debris = N/A ft 2 Overflow Grate Open Area % = 80% N/A %, grate open area/total area Overflow Grate Open Area w/ Debris = 6.62 N/A ft 2 Debris Clogging % = 50% N/A % User Input: Outlet Pipe w/ Flow Restriction Plate (Circular Orifice, Restrictor Plate, or Rectangular Orifice) Calculated Parameters for Outlet Pipe w/ Flow Restriction Plate Zone 3 Restrictor Not Selected Zone 3 Restrictor Not Selected Depth to Invert of Outlet Pipe = 0.00 N/A ft (distance below basin bottom at Stage = 0 ft) Outlet Orifice Area = 4.11 N/A ft 2 Outlet Pipe Diameter = N/A inches Outlet Orifice Centroid = 0.97 N/A feet Restrictor Plate Height Above Pipe Invert = inches Half-Central Angle of Restrictor Plate on Pipe = 1.70 N/A radians User Input: Emergency Spillway (Rectangular or Trapezoidal) Calculated Parameters for Spillway Spillway Invert Stage= 6.00 ft (relative to basin bottom at Stage = 0 ft) Spillway Design Flow Depth= 0.60 feet Spillway Crest Length = feet Stage at Top of Freeboard = 7.60 feet Spillway End Slopes = 4.00 H:V Basin Area at Top of Freeboard = 1.19 acres Freeboard above Max Water Surface = 1.00 feet Routed Hydrograph Results Design Storm Return Period = WQCV EURV 2 Year 5 Year 10 Year 25 Year 50 Year 100 Year 500 Year One-Hour Rainfall Depth (in) = Calculated Runoff Volume (acre-ft) = OPTIONAL Override Runoff Volume (acre-ft) = Inflow Hydrograph Volume (acre-ft) = Predevelopment Unit Peak Flow, q (cfs/acre) = Predevelopment Peak Q (cfs) = Peak Inflow Q (cfs) = Peak Outflow Q (cfs) = Ratio Peak Outflow to Predevelopment Q = N/A N/A N/A Structure Controlling Flow = Plate Plate Plate Plate Plate Overflow Grate 1 Overflow Grate 1 Outlet Plate 1 Spillway Max Velocity through Grate 1 (fps) = N/A N/A N/A N/A N/A Max Velocity through Grate 2 (fps) = N/A N/A N/A N/A N/A N/A N/A N/A N/A Time to Drain 97% of Inflow Volume (hours) = Time to Drain 99% of Inflow Volume (hours) = Maximum Ponding Depth (ft) = Area at Maximum Ponding Depth (acres) = Maximum Volume Stored (acre-ft) =

6 FLOW [cfs] Detention Basin Outlet Structure Design UD-Detention, Version 3.07 (February 2017) COUNTA for Basin Tab = 1 Ao Dia WQ Plate Type Vert Orifice 1 Vert Orifice 2 500YR Count_Underdrain IN = eter = 3/8 inch) YR OUT Count_WQPlate = eter = 7/16 inch) 100YR IN 100YR Count_VertOrifice1 OUT = eter = 1/2 inch) Outlet Plate 1 Outlet Plate 2 Drain Time Message Boolean 50YR Count_VertOrifice2 IN = eter = 9/16 inch) 4 1 5yr, <72hr 0 50YR OUT Count_Weir1 = eter = 5/8 inch) >5yr, <120hr 0 25YR IN Count_Weir2 = er = 11/16 inch) Max Depth Row 25YR OUT 10YR Count_OutletPipe1 IN = eter = 3/4 inch) WQCV 186 Watershed Constraint Check 10YR Count_OutletPipe2 OUT = er = 13/16 inch) 2 Year 260 Slope COUNTA_2 5YR (Standard IN FSD Setup)= eter = 7/8 inch) EURV 307 Shape 4.96 MaxPondDepth_Error? 5YR OUT FALSE 0.67 er = 15/16 inch) 5 Year 370 2YR IN Hidden Parameters & Calculations 0.76 meter = 1 inch) 10 Year 404 Spillway Depth 2YR OUT 0.86 = 1-1/16 inches) 25 Year EURV IN WQ Plate Flow at 100yr depth = = 1-1/8 inches) 50 Year 531 EURV OUT CLOG #1= 40% 1.08 = 1-3/16 inches) 100 Year Z1_Boolean WQCV IN C dw #1 = = 1-1/4 inches) 500 Year Z2_Boolean WQCV OUT C do #1 = = 1-5/16 inches) Zone3_Pulldown Message 1 Z3_Boolean Overflow Weir #1 Angle = = 1-3/8 inches) 1 Opening Message CLOG #2= #VALUE! 1.59 = 1-7/16 inches) Draintime Running C dw #2 = #VALUE! 1.73 = 1-1/2 inches) Outlet Boolean Outlet Rank Total (1 to 4) C do #2 = #VALUE! 1.88 = 1-9/16 inches) Vertical Orifice Overflow Weir #2 Angle = #VALUE! 2.03 = 1-5/8 inches) Vertical Orifice Boolean 0 Underdrain Q at 100yr depth = /16 inches) Overflow Weir Max Depth VertOrifice1 Q at 100yr depth = = 1-3/4 inches) Overflow Weir 2 TIME [hr] yr Depth VertOrifice2 Q at 100yr depth = /16 inches) Outlet Pipe Freeboard PONDING DEPTH [ft] 7 EURV_draintime_user = 2.72 = 1-7/8 inches) Outlet Pipe Spillway Count_User_Hydrographs 500YR /16 inches) 0 Spillway Length CountA_3 100YR(EURV & 100yr) = eter = 2 inches) Button Visibility Boolean FALSE Time Interval CountA_4 50YR (100yr Only) = gular openings) 1 Button_Trigger 25YR 10YR 5YR 2YR EURV WQCV 0 Underdrain 1 WQCV Plate 0 EURV-WQCV Plate 0 EURV-WQCV VertOrifice 1 Outlet 90% Qpeak 0 Outlet Undetained DRAIN TIME [hr] AREA [ft^2], VOLUME [ft^3] 400, , , , , , ,000 User Area [ft^2] Interpolated Area [ft^2] Summary Area [ft^2] Volume [ft^3] Summary Volume [ft^3] Outflow [cfs] Summary Outflow [cfs] 1, , , OUTFLOW [cfs] 50, PONDING DEPTH [ft] S-A-V-D Chart Axis Override X-axis Left Y-Axis Right Y-Axis minimum bound maximum bound

7 Storm Inflow Hydrographs Detention Basin Outlet Structure Design Outflow Hydrograph Workbook Filename: UD-Detention, Version 3.07 (February 2017) The user can override the calculated inflow hydrographs from this workbook with inflow hydrographs developed in a separate program. SOURCE WORKBOOK WORKBOOK WORKBOOK WORKBOOK WORKBOOK WORKBOOK WORKBOOK WORKBOOK WORKBOOK Time Interval TIME WQCV [cfs] EURV [cfs] 2 Year [cfs] 5 Year [cfs] 10 Year [cfs] 25 Year [cfs] 50 Year [cfs] 100 Year [cfs] 500 Year [cfs] 6.74 min 0:00: :06: Hydrograph 0:13: Constant 0:20: :26: :33: :40: :47: :53: :00: :07: :14: :20: :27: :34: :41: :47: :54: :01: :08: :14: :21: :28: :35: :41: :48: :55: :01: :08: :15: :22: :28: :35: :42: :49: :55: :02: :09: :16: :22: :29: :36: :43: :49: :56: :03: :10: :16: :23: :30: :37: :43: :50: :57: :03: :10: :17: :24: :30: :37: :44: :51: :57: :04: :11: :18: :24: :31: :38: :45: :51: :58: :05:

8 UD-Detention, Version 3.07 (February 2017) Summary Stage-Area-Volume-Discharge Relationships The user can create a summary S-A-V-D by entering the desired stage increments and the remainder of the table will populate automatically. The user should graphically compare the summary S-A-V-D table to the full S-A-V-D table in the chart to confirm it captures all key transition points. Stage - Storage Description Detention Basin Outlet Structure Design Stage Area Area Volume Volume Total Outflow [ft] [ft^2] [acres] [ft^3] [ac-ft] [cfs] For best results, include the stages of all grade slope changes (e.g. ISV and Floor) from the S-A-V table on Sheet 'Basin'. Also include the inverts of all outlets (e.g. vertical orifice, overflow grate, and spillway, where applicable).

9 PROJECT : Willow Bend 1 DATE : 3/30/2018 PROJECT NO. : BY : IC Grate Capacity Calculations - TEMPORARY DETENTION POND 0 A. Verify grate can pass the 100-year flow: Q 100 = cfs Determine the area necessary to pass the required flow through grate: A = Q / (C*(2GH) 1/2 ) Q: cfs C: 0.65 G: 32.2 ft/s 2 H: 2.30 ft A open = 4.59 ft 2 (Required) Try: CDOT Close Mesh Grate Grate size: (L*W) 5.67 X 2.92 ft Area of grate = Ft 2 Bars Across Length Bar size: 4.0 in deep X 0.38 in wide spaced at 2.38 inches OC No. of bars = [(W ft * 12 in/ft) / Sp(in)] + 1 = 16 Bars Area of bars = L Bar * W Bar * Number of bars = 2.84 ft 2 Bars Across Width Bar size: in deep X 0.38 in wide spaced at 8 inches OC No. of bars = [(W ft * 12 in/ft) / Sp(in)] + 1 = 5 Bars Area of bars = L Bar * W Bar * Number of bars = 0.46 ft 2 Area of grate open to flow = A Grate - A Bars = ft 2 % Open = 80.1% Area** 6.63 Ft 2 > 4.59 Ft 2 Grate can pass the required flow ** 50% reduction of the open area of the inlet has been applied for a clogging factor

10 Chapter 12 Storage TEMPORARY DETENTION POND #0 RIPRAP RUNDOWN Figure Embankment protection details and rock sizing chart (adapted from Arapahoe County) September 2017 Urban Drainage and Flood Control District Urban Storm Drainage Criteria Manual Volume 2

11 Chapter 12 Storage TEMPORARY DETENTION POND #0 SPILLWAY RIPRAP Figure Embankment protection details and rock sizing chart (adapted from Arapahoe County) September 2017 Urban Drainage and Flood Control District Urban Storm Drainage Criteria Manual Volume 2

12 Determination of Culvert Headwater and Outlet Protection Project: Basin ID: Willow Bend 1 Sediment Pond 0 - Outfall Soil Type: Choose One: Sandy Non-Sandy Design Information (Input): Design Discharge Q = 36.3 cfs Circular Culvert: Barrel Diameter in Inches D = 36 inches Inlet Edge Type (Choose from pull-down list) Box Culvert: OR Barrel Height (Rise) in Feet Height (Rise) = ft Barrel Width (Span) in Feet Width (Span) = ft Inlet Edge Type (Choose from pull-down list) Number of Barrels No = 1 Inlet Elevation Elev IN = 5233 ft Outlet Elevation OR Slope Elev OUT = ft Culvert Length L = ft Manning's Roughness n = Bend Loss Coefficient k b = 0 Exit Loss Coefficient k x = 1 Tailwater Surface Elevation Elev Y t = ft Max Allowable Channel Velocity V = 5 ft/s Required Protection (Output): Tailwater Surface Height Y t = 1.20 ft Flow Area at Max Channel Velocity A t = 7.26 ft 2 Culvert Cross Sectional Area Available A = 7.07 ft 2 Entrance Loss Coefficient k e = 0.20 Friction Loss Coefficient k f = 1.00 Sum of All Losses Coefficients k s = 2.20 ft Culvert Normal Depth Y n = 1.97 ft Culvert Critical Depth Y c = 1.96 ft Tailwater Depth for Design d = 2.48 ft Adjusted Diameter OR Adjusted Rise D a = - ft Expansion Factor 1/(2*tan(Θ)) = 5.32 Flow/Diameter 2.5 OR Flow/(Span * Rise 1.5 ) Q/D^2.5 = 2.33 ft 0.5 /s Froude Number Fr = 0.98 Tailwater/Adjusted Diameter OR Tailwater/Adjusted Rise Yt/D = 0.40 Inlet Control Headwater HW I = 2.89 ft Outlet Control Headwater HW O = 2.69 Design Headwater Elevation HW = 5, ft Headwater/Diameter OR Headwater/Rise Ratio HW/D = 0.96 Minimum Theoretical Riprap Size d 50 = 6 in Nominal Riprap Size d 50 = 6 in UDFCD Riprap Type Type = VL Length of Protection L p = 17 ft Width of Protection T = 7 ft

13 Channel Report Hydraflow Express Extension for Autodesk AutoCAD Civil 3D by Autodesk, Inc. Wednesday, May TEMPORARY DETENTION POND 0 - OUTFALL PIPE ANALYSIS Circular Diameter (ft) = 3.00 Invert Elev (ft) = Slope (%) = 0.50 N-Value = Calculations Compute by: Known Q Known Q (cfs) = Highlighted Depth (ft) = 1.98 Q (cfs) = Area (sqft) = 4.96 Velocity (ft/s) = 7.31 Wetted Perim (ft) = 5.70 Crit Depth, Yc (ft) = 1.96 Top Width (ft) = 2.84 EGL (ft) = 2.81 Elev (ft) Depth (ft) Section Reach (ft)

14 PROJECT : Willow Bend DATE : 5/22/2018 PROJECT NO. : BY : IC Sediment Basin Calculations - TEMP.SED. BASIN #1 Required Sediment Basin Volume Tributary Area (ac) Provided Volume Contour Elevation Actual Elevation Total Required Volume = 1.50 ac-ft ( Volume = 3600 CF/AC ) = 65,232 ft3 = 32,616 ft3 (50% Volume) Ft 2 1/3 (A1 + A2 + (A1A2) 1/2 ) D Total Volume (ft 3 ) Total Volume (ac-ft) 12, ,782 13,773 13, ,887 15,823 29, ,164 18,014 47, ,548 20,344 67, ,963 22,745 90, ,479 Elevation Depth Pond Overflow Crest Elev= % Sediment Basin Water Elev= Sediment Basin Water elevation= JANSEN STRAWN CONSULTING ENGINEERS 1165 S. Pennsylvania St. - Denver, CO p: f:

15 PROJECT : Willow Bend DATE : 5/22/2018 PROJECT NO. : BY : IC Overflow Weirs - TEMP.SED. BASIN #1 Pond Weir Tributary Area (ac) Depth (100-yr) Basin Slope (%) Basin Length (ft) % Soil Type %: A= 0.00% B= 0.00% C= % Max Allowable Release Rate Q 100 = cfs (q= 1.19 cfs/ac) aq (Equation 12-5) Weir Equation=>Q=CLH 3/2 Try Weir Release: Q 100 = cfs C= 3.00 L= 28 ft Flow Depth= 0.38 ft USE: 28' JANSEN STRAWN CONSULTING ENGINEERS 990 S. Broadway - Denver, CO p: f:

16 5 Faircloth Skimmer Cut Sheet J. W. Faircloth & Son, Inc Coupling Sch 40 INCLUDED coupling But connection not attached 1 5 pvc float 2 Vent with Silver tip Inlet 5 Aluminum straps suspending inlet 4 Sch 40 SOLID pvc barrel or arm SUPPLIED BY USER hose, ss clamps 4 threaded male nipple on outlet end 1 5 inlet extension 4 4 HEAD on center of inlet and orifice Skimmer shown in floating position 1. Hose attached to outlet using the threaded 4 nipple. Typical methods used: on a metal structure a steel stubout welded on the side at the bottom to the side with a 4 threaded coupling or reducers; on a concrete structure with a hole or orifice at the bottom, use a steel plate with a hole cut in it and coupling welded to it that will fit over the hole in the concrete and bolted to the structure with sealant. 2. Dimensions are approximate, not intended as plans for construction. 3. Barrel (solid, not foam core pipe) should be 1.4 times the depth of water with a minimum length of 8 so the inlet can be pulled to the side for maintenance. If more than 10 long weight may have to be added to inlet to counter the increased buoyancy. 4. Inlet tapers down from 5 maximum inlet to a 4 barrel and hose. Barrel is smaller to reduce buoyancy and tendency to lift inlet but is sufficient for flow through inlet because of slope. The inlet orifice can be reduced using the plug and cutter provided to control the outflow rate. 5. Inlet is 8 pipe between the straps with slots cut in the inlet and aluminum screen door (smaller than shown in illustration) for access to the 5 inlet and orifice inside. 6. Capacity 32,832 cubic feet per day maximum with 5 inlet and 4 head. Inlet can be reduced by installing a smaller orifice using the plug and cutter provided to adjust flow rate for the particular basin volume and drawdown time required. 7. Shipped assembled. User glues inlet extension and barrel, installs vent, cuts orifice in plug and attaches to outlet pipe or structure. Includes flexible hose, rope, orifice cutter, etc. 5inchCut TM November 14, 2007

17 Chapter 12 Storage TEMPORARY SEDIMENT POND #1 RIPRAP RUNDOWN Figure Embankment protection details and rock sizing chart (adapted from Arapahoe County) September 2017 Urban Drainage and Flood Control District Urban Storm Drainage Criteria Manual Volume 2

18 Chapter 12 Storage TEMPORARY SEDIMENT POND #1 SPILLWAY RIPRAP Figure Embankment protection details and rock sizing chart (adapted from Arapahoe County) September 2017 Urban Drainage and Flood Control District Urban Storm Drainage Criteria Manual Volume 2

19 Channel Report Hydraflow Express Extension for Autodesk AutoCAD Civil 3D by Autodesk, Inc. Friday, Apr TEMPORARY DIVERSION DITCH EC-A-A TO SEDIMENT BASIN #1 Trapezoidal Bottom Width (ft) = 4.00 Side Slopes (z:1) = 5.00, 5.00 Total Depth (ft) = 2.00 Invert Elev (ft) = Slope (%) = 2.06 N-Value = Calculations Compute by: Known Q Known Q (cfs) = Highlighted Depth (ft) = 0.85 Q (cfs) = Area (sqft) = 7.01 Velocity (ft/s) = 4.04 Wetted Perim (ft) = Crit Depth, Yc (ft) = 0.83 Top Width (ft) = EGL (ft) = 1.10 Elev (ft) Depth (ft) Section Reach (ft)

20 PROJECT : Willow Bend DATE : 5/22/2018 PROJECT NO. : BY : IC Sediment Basin Calculations - TEMP.SED. BASIN #2 Required Sediment Basin Volume Tributary Area (ac) Provided Volume Contour Elevation Actual Elevation Total Required Volume = 1.28 ac-ft ( Volume = 3600 CF/AC ) = 55,908 ft3 = 27,954 (50% Volume) Ft 2 1/3 (A1 + A2 + (A1A2) 1/2 ) D Total Volume (ft 3 ) Total Volume (ac-ft) 10, ,531 11,619 11, ,433 13,471 25, ,436 15,424 40, ,539 17,477 57, ,742 19,630 77, ,047 21,884 99, Elevation Depth Pond Overflow Crest Elev= % Sediment Basin Water Elev= Sediment Basin Water elevation= JANSEN STRAWN CONSULTING ENGINEERS 1165 S. Pennsylvania St. - Denver, CO p: f:

21 PROJECT : Willow Bend DATE : 5/22/2018 PROJECT NO. : BY : IC Overflow Weirs Pond Weir Tributary Area (ac) Depth (100-yr) Basin Slope (%) Basin Length (ft) % Soil Type %: A= 0.00% B= 0.00% C= % Max Allowable Release Rate Q 100 = cfs (q= 1.15 cfs/ac) aq (Equation 12-5) Weir Equation=>Q=CLH 3/2 Try Weir Release: Q 100 = cfs C= 3.00 L= 22 ft Flow Depth= 0.39 ft USE: 22' JANSEN STRAWN CONSULTING ENGINEERS 990 S. Broadway - Denver, CO p: f:

22 Channel Report Hydraflow Express Extension for Autodesk AutoCAD Civil 3D by Autodesk, Inc. Tuesday, May TEMPORARY SWALE EC-C-C TO SEDIMENT BASIN #2 Trapezoidal Bottom Width (ft) = 2.00 Side Slopes (z:1) = 5.00, 5.00 Total Depth (ft) = 1.20 Invert Elev (ft) = Slope (%) = 1.52 N-Value = Calculations Compute by: Known Q Known Q (cfs) = Highlighted Depth (ft) = 1.08 Q (cfs) = Area (sqft) = 7.99 Velocity (ft/s) = 3.78 Wetted Perim (ft) = Crit Depth, Yc (ft) = 1.00 Top Width (ft) = EGL (ft) = 1.30 Elev (ft) Depth (ft) Section Reach (ft)

23 Sediment Basin (SB) SC-7 August 2013 Urban Drainage and Flood Control District SB-5 Urban Storm Drainage Criteria Manual Volume 3

24 SC-7 Sediment Basin (SB) SB-6 Urban Drainage and Flood Control District August 2013 Urban Storm Drainage Criteria Manual Volume 3

25 Sediment Basin (SB) SC-7 August 2013 Urban Drainage and Flood Control District SB-7 Urban Storm Drainage Criteria Manual Volume 3