2012-11-05_REVISION - C1982056 (5)

Home Browse Search

of a contour furrow is depicted in Figure 13 Design of Typical Contour Furrow. According to data derived from studies at the Energy Mine No. 1, the water detention capacity of these furrows, when spaced thirty feet apart, is 2,599.7 cubic feet per acre. A brief evaluation of the total projected impact from a 10 -year, 24- hour rainfall event is illustrative of the effectiveness of chisel plowing and contour furrowing techniques. The projected precipitation from a 10 -year, 24 -hour rainfall event is 1.8 inches, or 6,534 cubic feet per acre. The water detention capacity of reclaimed sites prepared with both chisel - plowing and contour furrowing techniques amounts to 5,121 cubic feet per acre, or 78% (1.41 inches) of the projected 10 -year, 24 -hour rainfall event. Therefore, the total amount of water capable of becoming surface runoff from a rainfall event of this magnitude is only .39 inches. Research recently conducted at Energy Mine No. 1 and at the Edna Mine demonstrates that a reasonable estimate for infiltration of water on reclaimed land is 85% of detention capacity (McWhorter, 1979:104; and John Gilley, USDA -SEA unpublished data). Hence, the infiltration potential of reclaimed lands within the proposed permit area is 1.19 inches or approximately three times greater than total potential surface water runoff (.39 inches) from a 10 -year, 24 -hour rainfall event. Consequently, the detention capacity and infiltration potential of reclaimed lands taken together, will allow all rainfall to be potentially available for plant growth and no surface runoff from reclaimed lands is expected. Due to the effectiveness of the two surface maniplulation techniques described above, TCC proposes to utilize chisel- plowing and contour furrowing as the primary methods of soil stabailization. 2.05 -36