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Stream Depletion by Ground Water Pumping. Garey A. Fox and Michael A. Kizer Associate Professor and Professor Oklahoma State University. Water Research Advisory Board Meeting, July 22, 2010 Cowboy and Western Heritage Museum, Oklahoma City, OK. Streams and Alluvial Aquifers
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Stream Depletion by Ground Water Pumping Garey A. Fox and Michael A. Kizer Associate Professor and Professor Oklahoma State University Water Research Advisory Board Meeting, July 22, 2010 Cowboy and Western Heritage Museum, Oklahoma City, OK
Streams and Alluvial Aquifers Hydraulically connected – a single resource Ground water pumping adjacent to rivers depletes streamflow (“alluvial well depletion”) Research Question: Is alluvial well depletion significant in OK rivers? Critical Water Issue Stream Leakage into the Alluvial Aquifer
Controlling Factors • Aquifer Properties: • T (or K), Sy • Pumping Well: • L, Q • Stream: • Ksb • Penetration Idealizations of Alluvial Well Pumping Adjacent to a Stream
Study Sites North Canadian River Washita River
Determine typical hydrogeologic cross-sections and aquifer parameters Measure local and reach-scale streambed conductivity Conduct long-term monitoring of stream/ground water levels and stream/aquifer analysis tests (4) Develop a stream depletion worksheet for estimating alluvial well depletion Objectives/Tasks North Canadian River Washita River
Hydrogeologic Cross-Sections: Field Site #1: North Canadian River ACOG: Electrical resistivity survey Schoff and Reed (1951): T = 870 m2/d Ryder (1996): Sy = 0.29 K = 48 m/d
Streambed conductivity (Ksb) measurements at site: Empirical equations from grain-size distribution Field Site #1: North Canadian River
Streambed conductivity (Ksb) measurements at site: Falling-head permeameter tests: Field Site #1: North Canadian River
Reach-scale streambed conductivity (Ksb) measurements: Field Site #1: North Canadian River
Field Site #1: North Canadian River • Stream-Aquifer Analysis Test… • Extract ground water and measure drawdown • Use analytical solution(s) to determine aquifer and streambed parameters • Use parameters to quantify stream depletion
Hydrogeologic Cross-Sections: Field Site #2: Washita River • Kent (1978): • 12 to 30 m thick • T = 100 to 400 m2/d • Sy = 0.30
Streambed conductivity (Ksb) measurements at site Empirical equations from grain-size distribution: Field Site #2: Washita River
Streambed conductivity (Ksb) measurements at site Falling-head permeameter tests: Field Site #2: Washita River
Reach-scale streambed conductivity (Ksb) measurements: Field Site #2: Washita River
Field Site #2: Washita River 5 days
Both rivers mimic fully penetrating streams with little to no hydraulic resistance by a streambed layer Streambed conductivity similar to aquifer conductivity Easier solutions for estimating stream depletion High stream depletion in wells located near the rivers Solutions used to develop an Oklahoma Stream Depletion Factor (OSDF) worksheet Primary Findings
Questions?E-mail: garey.fox@okstate.eduResearch Website: http://biosystems.okstate.edu/Home/gareyf