Drainage Report

oe ACS The next segment is shallow concentrated flow 174 If with a slope of 16.7% throtighawoodsnithtight underbrush. There is no discernable channel in the field along this path that would change the categorization of the flow type. Tc= 11.5 min. Proposed Tc - Sheet Flow 100 LF @1.7% grass cover Tc= 10.1 min Shallow concentrated flow 164If @ 3.05% Tc = 1.0 min, grass cover Shallow Concentrated Flow 50LF@ 5% Tc =.1 min, Pavement Cover Total Te= 11.2 min Un-detained Area associated with Basin 5 in this analysis. This is a large area from the clubhouse down Road D and up to the limit of Basin 5. It is disturbance beyond basin 5 and counts to the overall disturbance and discharge to the Canoe Brook tributary but not precisely to basin 5. The longest path is Sheet flow 100 If @ 12% over grass Tc=6.7min Shallow concentrated flow 20 If @5% grass cover Tc= .1 Shallow concentrated flow 118 Lf @ 5.5% pavement cover .4 min Pipe flow 156 If, 15 in, n=0.01, s= 3.49% Detention basin 5 collects water from the roof of building D2, the roadway on the east side of the site in front D2 and the grass area behind D2. The drainage in this area drains to the Canoe Brook Tributary. The table below outlines the results of the routing for this area. The small scale infiltration basin is listed as green technology for water quality, quantity and recharge in table 5.1 Quantity EXISTING REDUCED OL ** BASIN TOTAL** 2YR 3.33 1.67 2.94 0 2.94 10 YR 8.02 5.61 5.38 0.35 5.73 100 YR 18.05 14.44 10.39 2.86 13.25 ™ The un-detained area included in this basin is an internal point of analysis and includes all area downstream of basin 5. The point of analysis of the areas that discharge to the Canoe Brook Tributary as it leaves the property comply with the required discharge rates. See table on page 13 for the overall quantity compliance for the Canoe Brook Tributary Water Quality Small scale infiltration basins are listed as green technology for water quality when provided with pre- treatment. Basin 3 has a pre-treatment of a Cascade separator which provides 50% removal and the small-scale infiltration basin in series with it provides a total suspended solid removal of 90% for the detained portion of Basin 5. 10 Anderson Consulting Services LLC 40 Miller Drive, Boonton, NJ 07005 973-975-0703 (O) 973-886-7336 (C) PAndersonpe@gmail.com