A. Topographic Map: A topographic survey of the property at two foot (2') contours under existing and proposed conditions, and areas upstream and downstream, necessary to determine off site impacts of the proposed drainage plan. One foot (1') intervals may be required if deemed necessary by the county engineer. The map shall be keyed to USGS elevations in English units as specified by the county.
B. Drainage System: Mapping and descriptions, where relevant, of existing and proposed drainage system features of the property and immediate vicinity including:
1. The banks and centerline of streams and channels;
2. Shoreline of lakes, ponds, and detention basins;
3. Farm drains and tiles;
4. Sub-watershed boundaries within the property;
5. Watershed soils classifications;
6. The property's location within the larger watershed;
7. Location, type, size and slope of stormwater conduits and drainage swales;
8. Sanitary or combined sewers;
9. Existing depressional storage areas;
10. Delineation of upstream and downstream drainage features and watersheds which might be affected by the development;
11. Detention facilities;
12. Roads and streets and associated stormwater inlets;
13. Base flood elevation, and regulatory floodway where identified for the property; and
14. Basis of design for the final drainage network components, including supporting calculations.
C. Environmental Features: A depiction of environmental features of the property and immediate vicinity including the following:
1. The limits of wetland areas as depicted upon the appropriate wetland delineation map from the USDA soil conservation service and/or the U.S. fish and wildlife service national wetland inventory maps.
2. Any designated natural areas; and
3. Any proposed environmental mitigation features.
D. Erosion And Sedimentation Plan: A plan depicting the methods utilized to control erosion and sedimentation with BMPs. (Ord., 2-22-1999)