HR: 1330h
AN: H33B-04    [Abstracts]
TI: Technology for Evaluating Direct Recharge in a Juniper Dominated Karst Landscape
AU: * Gregory, L F
EM: lucasgregory@tamu.edu
AF: Department of Rangeland Ecology and Management, Texas A and M University, 2126 TAMU, College Station, TX 77843-2126 United States
AU: Veni, G
EM: gveni@satx.rr.com
AF: George Veni and Associates, 11304 Candle Park, San Antonio, TX 78249-4421 United States
AU: Wilcox, B P
EM: bwilcox@tamu.edu
AF: Department of Rangeland Ecology and Management, Texas A and M University, 2126 TAMU, College Station, TX 77843-2126 United States
AU: Munster, C L
EM: c-munster@tamu.edu
AF: Department of Biological and Agricultural Engineering, Texas A and M University, 2117 TAMU, College Station, TX 77843-2117 United States
AU: Owens, M K
EM: m-owens@tamu.edu
AF: Department of Rangeland Ecology and Management, Texas A and M University, 2126 TAMU, College Station, TX 77843-2126 United States
AB: Non-native woody plant encroachment in semi-arid regions of the world has caused speculation about the influences of such encroachment on groundwater and surface water flows, interactions, and future availability. Our study is focused north of San Antonio in an Ashe juniper dominated cavernous karst landscape. The goal of this research is to identify and quantify all aspects of the water balance equation under forested and unforested conditions. Using a large scale rainfall simulator allows recreation of rainfall events where amount, rate, and duration of water applied are known. The cave footprint is instrumented with throughfall collectors and rain gauges to quantify throughfall and aid in estimation of interception. Four trees within the plot are instrumented with stemflow collectors and transpiration measurement devices that record data that are later scaled up to account for the entire plot. Drip collectors are constructed inside the cave from PVC pipe and clear polyurethane plastic sheeting that direct recharge to electronic tipping buckets that record onto a datalogger. Continuous automatic recording of cave recharge allows us to see the effects of simulated and natural rainfall events on recharge rates, volumes, and durations. Preliminary analysis of natural and simulated data has shown us that the cave does receive significant quantities of recharge. Thus far, we have concluded that the cave is more sensitive to natural rainfalls than re-created rainfalls, suggesting that the catchment area of the cave is larger than its footprint.
DE: 1836 Hydrologic budget (1655)
SC: Hydrology [H]
MN: 2005 Joint Assembly