HR: 1340h
AN: B33D-1072    [Abstracts]
TI: Runoff From a Spring-Fed Rangeland Catchment and Influence of Woody Plants
AU: * Huang, Y
EM: yunh@tamu.edu
AF: Water Management and Hydrologic Science, Texas A&M University, College Station, TX 77843 United States
AU: Wilcox, B P
EM: bwilcox@tamu.edu
AF: Rangeland Ecology and Management, Texas A&M University, College Station, TX 77843 United States
AU: Perotto, H
EM: hperotto@tamu.edu
AF: Rangeland Ecology and Management, Texas A&M University, College Station, TX 77843 United States
AB: The possibility that streamflow may be increased through control of woody plants is a particularly appealing one for arid or semiarid rangelands. However, few studies have documented that such a method is effective (except in Mediterranean and some humid climates). Some researchers suggest that it may also be effective in areas that naturally support spring flow-such as those having an underlying karst geology- but this is far from well documented. In this study, we characterize runoff from a small karst catchment that supports spring flow and evaluate the extent to which runoff changed following removal of most of the woody plant cover (Ashe juniper) using hydrometric as well as isotopic characterization. At the study site, a 19-ha catchment on the Edwards Plateau, we monitored streamflow for four years (two before plant removal and two following removal). Hydrograph separation indicated that the contribution to runoff from pre-event water was substantially greater for the winter event (about 46%) than for the summer event (only about 16%).We found that (1) runoff made up about 22% of the water budget, the annual percentage varying from 4% to 34% during the four observation years; (2) almost 80% of the runoff was generated by the largest 20% of the runoff-producing storms; (3) streamflow did increase following removal of juniper, by about 60% (p<0.04), or about 64 mm annually; and (4) most increase occurred in the non-summer (October to April) period. This is the largest scale experiment of its kind in this area and these results are important because they demonstrate that where springs are present, runoff may be augmented by decreasing woody plant cover.
DE: 0481 Restoration
DE: 0495 Water/energy interactions (1878)
DE: 0498 General or miscellaneous
DE: 1813 Eco-hydrology
DE: 1876 Water budgets
SC: Biogeosciences [B]
MN: Fall Meeting 2005