Stonnwater and Sediment 



d) Depth to seasonal groundwater levels, approximate direction and rate of flow, 

 seasonal fluctuations; 



e) Location of 100 year flood zones; 



f) Principal vegetation types; 



g) Topography described in full contour detail, at 2 foot intervals, with areas of steep 

 slopes (over 10%) highlighted; 



h) Soils, with an accompanying analysis of the best use potential of the soils and the 

 hydrologic group classification; the soils map and use analysis prepared by the US 

 Soil Conservation Service should be used as the basis for this analysis. 



Proposed alterations of the site must be described in detail, as follows, including: 



a) Changes in topography, described in full contour details at 2 foot intervals; 



b) Areas where vegetation will be cleared or otherwise altered; 



c) Areas that will be covered with an impervious surface and a description of the 

 surfacing material; 



d) The proposed development layout including; 



i) The site arrangement, including the location of structures, roadways, parking 



areas, sewage disposal facilities, and undisturbed lands. 

 ii) All (irainage systems to be provided, including the location and design of 



roadway and individual lot sub-drains; full drainage calculations shall be 



included, with 1 or 2 year, 10 year, and 100 year storms used as the basis of 



design. 



Predicted impacts of the proposed development on existing conditions must be 

 described in detail, including: 



a) Changes in water quality; 



b) Changes in groundwater levels: 



c) Changes in the incidence and duration of flooding on the site and upstream and 

 downstream from it; 



d) Adverse impacts on wedands; 



e) Impacts on vegetation; 



Drainage system components and all measures for the detention, retention, or infiltration 

 of water or for the protection of water quality must be described in detail, including: 



a) The channel, direction, volume, and rate of the flow (CFS), and quality of 

 stonnwater that will be conveyed from the site, with a comparison to existing 

 condition, and to the extent practicable, predevelopment conditions; 



b) Detention and retention areas and devices, including; 



151 



