SLV Groundwater Level Study 2007

Home Browse Search

tributary to the Rio Grande and subject to the Rio Grande Compact. The location of the hydraulic divide changes in response to pumping stress north of the river and there is concern that the divide now coi ncides with the river . If this is the case, pumping of unconfined wells is causing depletion of the river and administration issues must be addressed . Therefore, the Plan for Water Management can not be completed until the location of the hydraulic divid e is identified. Subdistrict No. 2 Groundwater Levels Although not the same as the hydraulic divide in the Closed Basin, proposed Subdistrict No. 2 is located along the divide between the Rock Creek drainage and the Rio Grande. The groundwater flow dire ction and relative elevation compared to these two drainages is likely to be an important regulating component in their Plan for Water Management. Their plan is to maintain a positive gradient to the river. The goals of the proposed Subdistrict Plan for Water Management will be to maintain groundwater levels within a range that provides an adequate water supply for wells and replace identified depletions to senior surface water rights. The proposed area of study is approximately within the proposed bound aries of Subdistrict No. 2 as shown on the map included as Figure 1 . S COPE OF WORK H ydraulic Divide Study The study plan includes measuring the location and elevation of existing wells on a ±½ mile grid beginning at the river and extending northeasterl y from three to five miles. Wells will be located within the respective shaded area shown on the map attached as Exhibit A. Depth to groundwater will be measured in each well and converted to M.S.L. elevation using the survey elevation of the measuring p oint . River water elevations will also be obtained where the southerly edge of the study area meet s the Rio Grande. Davis Engineering proposes to use GPS equipment to accomplish the surveying. Ultimately, the measured river and groundwater elevations wi ll be mapped and groundwater contours will be plotted. Contour configuration will then be used to map the location of the hydraulic divide. The final product will consist of a GIS based map, compatible with RGDSS GIS mapping, containing the location of a ll wells in which the groundwater level was measured. The well locations will be in NAD 1983, UTM coordinates, Zone 13 N . Using measured groundwater levels at the wells, a groundwater level contour map will be prepared on the GIS map. Subdistrict No. 2 Groundwater Levels Similar to the Hydraulic Divide Study, the plan of study for Subdistrict No. 2 Groundwater Levels includes measuring the location and elevation of existing wells on a 2