A QUANTITATIVE ANALYSIS OF SHALLOW GROUNDWATER MANAGEMENT ON BOSQUE DEL APACHE NATIONAL WILDLIFE REFUGE, NEW MEXICO

The Bosque del Apache National Wildlife Refuge (Refuge) in south central New Mexico is the site of seasonal wetlands that support habitat for year-round and migratory wildlife. Water is managed at the Refuge to support agricultural plots, riparian zones, and the needs of endangered species. The Refuge currently uses a monthly time step model that integrates a variety of estimated and empirical data to develop the hydrologic budget for irrigation water. However, until this study there have been no direct measurements of how much water is infiltrating from managed wetlands into the shallow ground water. It is important to improve the accuracy of water budget estimates by developing infiltration rates based on empirically derived data. In order to accomplish this goal, we focused on 4 hydrologically distinct wetlands comprised of agriculture land, forested grass land, and flood plain mixed with conifer forest and riparian vegetation. These units were selected to represent different parts of the Refuge with unique soil texture and water management. Data collected on a weekly basis included flow measurements at 4 inflow and 4 outflow structures, daily staff plate readings, and ground water levels at 20 monitoring sites. The data are being integrated into a wetland ArcGIS tool to quantify aspects of the Refuge water budget. We hypothesize that any loss of water is due to infiltration, leakage, and evapotranspiration. Preliminary ground water well levels around each wetland unit show positive correlations (increase in height) after surface water introduction to the managed units. Further data analysis is needed to correlate the overall picture of how the managed wetlands function with respect to infiltration and consumptive properties. The final project outcome will be a quantification of infiltration rates within the 4 selected wetlands that will be scaled out to represent all Refuge wetlands in order to create an accurate water budget. This study will inform water resources managers about the connectivity between surface and ground water systems and the availability of water applied to the wetlands for water needs within and beyond the refuge property.