Each applicant shall submit the following information, depending on development size, to ensure that the provisions of this chapter are met. The submittal shall include sufficient information to evaluate the environmental characteristics of the property, the potential adverse impacts of the development on water resources both on site and downstream, and the effectiveness of the proposed drainage plan in managing storm water runoff. The following information shall be submitted concurrently with the development plans for both existing and proposed property conditions.
Properties smaller than forty (40) acres shall submit only the basic drainage plan called for in subsection A of this section. Properties larger than forty (40) acres shall comply with the submittal requirements of both the basic drainage plan and the advanced drainage plan of subsection B of this section. For properties smaller than forty (40) acres, the submittal of the advanced drainage plan may be required, when deemed necessary by the village engineer.
A. Basic Drainage Plan:
1. Topographic Map: A topographic survey of the property at one foot (1') or two foot (2') contours under existing and proposed conditions, and all adjacent land within one hundred feet (100') of the boundary of the property and any areas upstream and downstream, necessary to determine off site impacts of the proposed drainage plan. The map shall be keyed to the United States geological survey national geodetic vertical datum of 1929.
2. Drainage System: Mapping and descriptions, where relevant, of existing and proposed drainage system features of the property and immediate vicinity including:
a. The banks and centerline of streams and channels;
b. Shoreline of lakes, ponds, and detention basins;
c. Any known farm drains and tiles;
d. Subwatershed boundaries within the property (including basin and inlet tributary areas);
e. Watershed soils classifications;
f. The property's location within the larger watershed;
g. Location, size and slope of storm water conduits and drainage swales;
h. Existing sewers or other utilities on the property;
i. Depressional storage areas;
j. Delineation of upstream and downstream drainage features and watersheds which might be affected by the development;
k. Detention facilities (including high water level and emergency overflow elevations and locations);
l. Roads and streets and associated storm water inlets;
m. 100-year flood limits and elevation, and regulatory floodway where identified for the property;
n. Basis of design (proposed methodology) for the final drainage network components;
o. The limits of wetland areas;
p. Any designated natural areas; and
q. Any proposed environmental mitigation features.
B. Advanced Drainage Plan: The same information as required in subsection A of this section is required for properties larger than forty (40) acres along with the following additional information for the minor drainage system's design runoff event and the 100-year runoff event of critical duration. The submittal of the advanced drainage plan may be required, when deemed necessary by the village engineer:
1. Elevations and maps of 100-year flooding;
2. Cross section data for open channel flow paths and designated overland flow paths;
3. Routing and direction of storm flows;
4. Flow rates and velocities at representative points in the drainage system; and
5. A statement by the design engineer of the drainage system's provisions for handling events greater than the 100-year's runoff. (Ord. 1630, 4-12-1999)