Water Resources Research Act Program

Details for Project ID 2009OK119B

Stream Depletion by Ground Water Pumping: A Stream Depletion Factor for the State of Oklahoma

Institute: Oklahoma
Year Established: 2009 Start Date: 2009-03-01 End Date: 2010-08-15
Total Federal Funds: $25,000 Total Non-Federal Funds: $50,002

Principal Investigators: Garey Fox, Mike Kizer

Abstract: Long-term planning and development of a comprehensive water plan requires an understanding of surface and ground water availability and the depletive effects of all water uses within a basin. Standardized methods can be developed for determining the effects of alluvial ground water pumping and/or recharge on stream flow. For example, Colorado uses a stream depletion factor (SDF) to estimate the influence of alluvial pumping on adjacent streamflow. However, these SDFs are based on analytical solutions developed in the 1960s. Significant research advances have been made in the past 10 years on developing solutions that better represent the physical reality of the system: (1) streams commonly do not extend throughout the entire saturated thickness of the alluvial aquifer and (2) streams commonly have a streambed with different hydraulic characteristics than the underlying alluvial aquifer. The objective of this research is to develop an Oklahoma SDF, called the OSDF, for analyzing the impact of stream depletion of surface water by ground water pumping, either by irrigation wells or domestic water use. The stream depletion methodology will mimic systems utilized by western states such as Colorado; however, the proposed methodology is based on state-of-the-art analytical solutions. Specific tasks include the following: (1) measuring streambed conductivity in two major alluvial river systems in the state of Oklahoma (i.e., North Canadian River and Washita River) using grain size analyses and/or falling head permeameter tests; (2) developing a database of geologic characterization (i.e., depth and extent of the alluvial aquifer) and aquifer parameters for specific reaches along the North Canadian and Washita River alluvial aquifers and identify critical areas where additional parameterization is needed; (3) long-term monitoring of stream and ground water levels during both recharge and pumping conditions and conducting stream/aquifer analysis tests to evaluate existing analytical solutions and determine applicability of the solutions at one field site within each alluvial aquifer; and (4) developing a modified SDF based on new and improved analytical solutions for stream depletion by ground water pumping. The benefit of such a stream depletion tool is that it allows water managers the opportunity to determine short-term and/or long-term impact of ground water pumping on the availability of surface water resources. For example, the SDF system can be used to determine the impact of upstream irrigation or domestic wells on water supply to downstream users. Such a system will impact the management of water resources in the state of Oklahoma by assessing the limitation in current water policy regarding surface water and ground water interaction in alluvial systems. Further examination of these alluvial aquifers will also provide an updated estimate of the quantity of water stored within these alluvial systems, which will benefit the development of a comprehensive water plan.