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IMPACT OF IRRIGATION WELLS ON BASEFLOW OF THE BIG BLUE RWER, NEBRASKA 1
Author(s) -
Tabidian M.,
Pederson Darryll T.
Publication year - 1995
Publication title -
jawra journal of the american water resources association
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.957
H-Index - 105
eISSN - 1752-1688
pISSN - 1093-474X
DOI - 10.1111/j.1752-1688.1995.tb03381.x
Subject(s) - baseflow , hydrology (agriculture) , aquifer , groundwater , environmental science , irrigation , streamflow , hydrogeology , geology , drainage basin , geography , ecology , cartography , geotechnical engineering , biology
The Kansas‐Nebraska Big Blue River compact requires that the state of Nebraska insure a minimum flow of the Big Blue River across the state line. There are two options that the state of Nebraska may use to ensure minimum flows. The obvious option is to limit surface‐water irrigators along the river. However, under the terms of the compact, a second option may be to regulate irrigation wells that are within one mile of the river and were installed after November 1, 1968. The objective of this study is to quantify the effects of 17 irrigation wells that may be regulated on baseflow of the Big Blue River. A finite‐element model is used to study the hydrogeologic system between DeWitt and Beatrice, Nebraska. The 17 wells that may be regulated are located between these towns and are developed in sediments deposited in a cross‐cutting paleovalley anchor alluvium associated with the Big Blue River. While there wore considerable existing data, additional data were gathered by drilling an additional nine test holes, conducting several aquifer tests, stream‐stage measurements, and baseflow calculation through extensive stream‐discharge measurements, establishment of a ground water‐level monitoring network, determining the amount of water pumped for irrigation and municipal use in the area, and a short‐term precipitation network. The model was calibrated using observed baseflow and ground water level data. The model clearly shows that regulating the 17 wells to maintain baseflow would have a minimal effect on the overall water budget. This is reasonable, especially considering that there are over 250 irrigation wells in the project area. The 17 wells considered pumped only 6 percent of the total pumpage within the modeled area during the irrigation season of 1984. The computer model provides the documentation needed to demonstrate this fact. Although much of the resources spent and a significant amount of hydrogeologic data are being collected over a period of three years on a relatively small area, the simulation model could be improved through further field testing of the aquifer and stream‐bed sediment characteristics and quantification of ground water recharge, discharge, and evapotranspiration rates.