2008-12-11_PERMIT FILE - C1980007A ‎(36)‎

• Permit No: C1980007A
• IBM Index Class Name: Permit File
• Doc Date: 12/11/2008
• Doc Name: Small Area Exemption Demonstrations
• Section_Exhibit Name: Exhibit 66 SAE
• Media Type: D
• Archive: Yes

S...
West Elk
Small Area Exemption (SAE)
Water Tank
1. INTRODUCTION
1.1 Methods of Analysis
This review and analysis is made using the Sediment, Erosion, Discharge by Computer Aided Design
(SEDCAD+ Version 3) developed by Nfs. Pamela J. Schwab of Civil Software Design and Dr. Richard C.
Warner, Agricultural Engineering Department, University of Kentucky. It is based on field information
provided by Kathy Welt and as referenced herein. `
1.2 Project Description
The project is a water tank on a level pad. Information provided includes:
1) That the tank is located as shown on the location map (Attachment 1).
2) That the tank is located on a level piece of ground in an area generally of 13% slopes. Only l' of cut
-:-= is required to prepare the pad. There is no fill slope.
3) The pad and associated perimeter roads are gravel surfaced (the pad was assumed to extend 12 feet
beyond the tank at an outslope of 0.5% in all directions).
4) The soil is (information from a soils boring) a silty sandy clay, moderate to highly expansive.
5) The upslope is oak brush, fair cover. The tank site is grass, fair cover.
Runoff from above the tank pad would be intercepted by a ditch and diverted around the site (1/2 to each
side)(see Attachment 2, SEDCAD+ File C:\SEDCAD3\WELK\SAEIDUP). Half the runoff from the tank
and pad would be directed away from the tank with distributed discharge downslope from the pad (see
Attachment 4, SEDCAD+ File C:\SEDCAD\WELK\SAETPDS). The other half of the runoff from the tank
and pad would be directed into the slope, joining the runoff from the cut slope, and released at point
discharges on both sides of the pad (1/2 to each side)(see Attachment 3, SEDCAD+ File
C.\SEDCAD\WELK\,SAECSTP). Thus this analysis considers a number of watersheds:
1) the watershed above the interceptor ditch.
2) the cut slope above the pad.
3) that half of the exposed part of the pad that drains into the slope.
4) that half of the tank cover that drains into the slope.
5) that half of the tank cover that drains downslope.
6) that half of the exposed part of the pad that drains downslope.
The perimeter drainage system crosses the access road to the site. As flows are so low, and ditch requirements
so shallow, an open-top water bar is suggested to transport runoff across the access road.