complete drainage report rev 9

Docusign Envelope ID: E802A2F1-2485-417E-948D-E0A4008C75BD POA#1 (Point of Analysis) Existing Conditions Tc Computations. This drainage area has a forested cover with very light underbrush due to deer over browsing. The path of the existing conditions Tc is shown on the Existing Conditions Drainage Area Map. The Tc (Time of Concentration) is calculated in the Hydrocad program with the factors shown on the map and is as follows: The Basin 1 contributing area is 395796.5 sf of Woods in good condition. The initial 100 lf (linear feet) is sheet flow with a slope of 4.5% in woods with light underbrush. Tc=14.9 min The next segment is shallow concentrated flow 1625 lf with a slope of 5.4% through woods with light underbrush. There is no discernable channel in the field along this path that would change the categorization of the flow type. Tc = 7.2 min. Total pre-development Tc= 22.1 minutes POA#2 Existing Conditions Tc Computations. This drainage area is in a forested cover with very light underbrush due to deer over browsing. The path of the existing conditions Tc is shown on the Existing Conditions Drainage Area Map. The Tc is calculated in the Hydrocad program with the factors shown on the map and is as follows. The Basin 2 contributing area is 808221.9 sf of Woods in good condition. The initial 100LF is sheet flow with a slope of 4.5% in woods with light underbrush. Tc=9.0 min The next segment is shallow concentrated flow 564 lf with a slope of 9.2% through woods with light underbrush. There is no discernable channel in the field along this path that would change the categorization of the flow type. Tc = 1.9 minutes. Total pre-development Tc= 16.8 minutes POA#3 Existing Conditions Point of analysis 3 discharges to an existing drainage system in Howell Drive. This municipal system flows to the east away from the onsite streams. This drainage area is only for disturbance associated with one half of the emergency access road . Existing Conditions are: woods with light underbrush. The existing Tc is calculated with the following factors. 100 LF. Of sheet flow @ 4% with woods coverage Tc= 15.8 minutes 70 lf of shallow concentrated Flow @ 11.5% woods cover. Tc= .2 Total Tc = 15.8 minutes 4