04.LaMettry - NURP - 061815Project: Audobahn Motorplex
Location: Chanhassen, Minnesota
Prepared for:
Prepared by Sathre-Bergquist, Inc.
Date: October 19, 2006
Updated: June 18, 2015
Nurp Design Pond
P =2.5 "Storm
Aw =19.35 Acres
Area of Parking Lots 5.84 Acres
Area Building Roofs =5.15 Acres
Additional Hardcover for Proposed Use
Aw =1.55 Acres Additional Drainage Area
Area of Parking Lots 0.74 Acres Additional Building over what was designed for in original report
Area Building Roofs =0.21 Acres Additional Parking over what was designed for in original report
Topology Area CN
Total Hardcover Area = 11.95 Acres 98
Grasscover (Existing) = 3.83 Acres 61
Grasscover (Proposed) = 4.52 Acres 58
Hardcover For Fi = 6.58 Acres (Streets & Drives) 98
CN =86 Weighted Mean CN
Fi = 0.57 Impervious Fraction
Pervious CN = 74.48
S = 1000/CN - 10 = 3.43 Maximum Soil Retention (inches)
Q = (P-.2S)(P-.2S)/(P+.8S)
Q = 0.63 Accumulated Direct Storm Runoff (inches)
V = QAw/12 =1.01 Permanent Pool Volume Required (Ac-Ft)
Ponding Dead Storage Volume Based on Plan Contours - 10:1 Bench Then 4:1 Slope
Contour Area (sf) Cummulative Storage(cf) (Acre-Feet)
897 Bottom 0 0 0.00
898 17063 8532 0.20
900 23171 48766 1.12
902 30143 102080 2.34
904 37850 170073 3.90
906 NWL 51912 259836 NWL 5.97 (Provided)
908 61309 373057 8.56
908.5 HWL 63774 404328 HWL 9.28
Dead Storage/Pond Surface Area =5.01