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3.5 Rernnstructed Drainageway Profiles (As-Built) <br />As agreed with the Division in Trapper's 1989 Annual Report (D.A. Berry Corres <br />6/8/90) Trapper is no longer required to provide as-built drainage profiles as part of the <br />annual report. <br />3.6 Permanent Diversion Establishment <br />As mentioned in a previous section, livestock watering tanks are often constructed on <br />water harvesting diversions to trap water on reclaimed sideslopes and make available <br />reliable water for wildlife/livestock use. <br />To increase the amount of water available to livestock tanks, appropriate water har- <br />vesting diversions may be removed immediately above the target diversion. The <br />remaining diversion and stock tank would be permanent landscape features. Permanent <br />water harvesting diversions are shown on the "Drainageway Reconstruction" map and <br />was approved by the Division in Trapper's 1989 Annual Report. <br />3.7 Results <br />Vegetation response, decreased flow rates and reduced gully formation were the pri- <br />mary factors in assessing the success of drainage reconstruction projects at Trapper <br />Mine. <br />Postmine herbaceous canopy cover, herbaceous production, and woody stem density <br />were evaluated in reconstructed drainage areas in 1988, 1989, and 1990, and compared <br />to sample data from undisturbed premine drainage areas. (Sampling was conducted on <br />drainageways reconstructed in 1987.) Various postmine drainage treatments were <br />incorporated to evaluate vegetation response on topsoiled, non-topsoiled, irrigated, and <br />non-irrigated drainage segments (Table 1). Treatments on undisturbed areas were irri- <br />gated and non-irrigated drainage segments (Table 1). Generally, vegetation measure- <br />ments were lower in reconstructed drainageways than in undisturbed drainage sites in <br />the initial growing season. However, by the end of the third growing season vegetation <br />parameters on reclaimed drainage areas were equal to or exceeded those measured on <br />undisturbed drainage areas. <br />Vegetation response was the best on topsoiled and irrigated treatments and was signifi- <br />cantly higher when comparing topsoiled versus non-topsoiled areas without irrigation. <br />The overall herbaceous canopy cover for all reconstructed drainage treatments in 1988 <br />(measure of initial growing season) was 39% compared to 71% on undisturbed drainage <br />segments. In 1989, herbaceous canopy cover had increased to 60% in reconstructed <br />drainages and decreased on undisturbed drainage segments to 69% cover. Herbaceous <br />canopy cover within postmine drainageways and in undisturbed drainages was equal at <br />65% in 1990. <br />Herbaceous primary production averaged 876 lbs/acre in reconstructed drainages and <br />1943 lbs/acre on undisturbed sites in 1988. In 1989, herbaceous primary production <br />decreased to 420 Ibs/acre on reconstructed drainages and 521 Ibs/acre on undisturbed <br />drainage segments. The reduction in production in 1989 compared to 1988 was a result <br />of severe drought conditions in the area during 1989. Herbaceous primary production <br />• averaged 1712 pounds/acre in postmine drainages and 1629 pounds/acre in undisturbed <br />drainages in 1990. <br />