Statistical estimation of streamflow depletion from irrigation wells

Abstract

[1] A multiple regression model was applied to annual time series data in an attempt to quantify the influence of irrigation wells on annual streamflows of Frenchman Creek in Southwestern Nebraska where intensive well development has taken place since 1950. A strong statistical relationship was found between the logarithm of streamflow and number of wells, current and lagged annual precipitation, and two variables that are the geometric mean of precipitation and number of wells in the current year and the year before last. Estimated mean streamflow from the statistical model in 1998 is approximately one third of that in 1950. A simpler model without the interaction terms between number of wells and precipitation was estimated for the Republican River near its final entry into Kansas from Nebraska, and an even greater decline in mean annual streamflow was found. The present mean is approximately one quarter of the 1950 level.

Evaluation of the impact of groundwater irrigation on streamflow in Nebraska

“…The average growth of the number of registered wells was over 1000 per year; even recently, the number of registered wells grew in 2002, 2003, and 2004. Intensive groundwater development for irrigation or other land use typically causes the depletion of nearby streamflow; the analysis of the hydrologic data for the Frenchman Creek in the Republican River basin by Burt et al (2002) suggested that streamflow depletion was closely related to the increase in the number of irrigation wells over the last 50 years. The impact of pumping on 0022-1694/$ -see front matter ª 2005 Elsevier B.V. All rights reserved.…”

Reply to comments provided by J. Szilagyi on “Evaluation of the impact of groundwater irrigation on streamflow in Nebraska” by Fujiang Wen and Xunhong Chen

“…For the Platte River basin, four gauging stations were detected with decreasing streamflow; for the Republican River basin, there were 20 gauges detected with decreasing streamflow''; for the temporal tendency using the data of 10-year periods, ''The Republican River basin had the biggest tendency in streamflow decreases; it started at seven stations in the 1970s, and occurred at more stations in later decades''. These findings presented in Wen and Chen (2006) have not been reported before, even though Szilagyi (1999Szilagyi ( , 2001 and others (Burt et al, 2002;Bennett and Howe, 1998) had analyzed streamflow trend for one or several gauging stations in a river basin of Nebraska. For instance, Szilagyi (1999Szilagyi ( , 2001) used a twosample t-test with a polynomial regression for step trend tests of seven gauging stations: 6821500, 6823000, 6827500, 6846500, 6849500, 6852500, 6853500, and a hydrological model to conduct the analysis on one gauging station: 6853500.…”

Analyzing streamflow changes: irrigation-enhanced interaction between aquifer and streamflow in the Republican River basin

“…The crop in the basin is heavily dependent on central pivot irrigation from pumping wells. Although lacking of well documented groundwater consumptive use data, studies have shown a strong statistical relationship between the number of pumping wells and stream depletion in this watershed (Burt et al, 2002). In this study, the pumping is estimated from annual irrigated crop acreage from the National Agricultural Statistics Service (USDA, 1999).…”

“…In this study, the Soil and Water Assessment Tool (SWAT) (Arnold et al, 1998), a widely used watershed management model is modified by linking the baseflow component to aquifer storage in order to simulate the complex effect of groundwater pumping and irrigation return flow on streamflow, and to understand the impact of irrigated agricultural development on streamflow change. The model is applied to the Frenchman Creek basin (FCB), a subbasin of the Republican River basin (RRB), where groundwater-fed irrigation has been developed in the area since the 1950s and considerable streamflow depletion has been reported (Burt et al, 2002). This case study will then illustrate the streamflow change in the context of stream-aquifer interaction under the effects of pumping and return flow.…”