Evaluation of water‐use policies for baseflow recovery during droughts in an agricultural intensive karst watershed: Case study of the lower Apalachicola–Chattahoochee–Flint River Basin, southeastern United States

Abstract

The lower Apalachicola–Chattahoochee–Flint River Basin in the Southeast United States represents a major agricultural area underlain by the highly productive karstic Upper Floridan aquifer (UFA). During El Niño Southern Oscillation‐induced droughts, intense groundwater withdrawal for irrigation lowers streamflow in the Flint River due to its hydraulic connectivity with the UFA and threatens the habitat of the federally listed and endangered aquatic biota. This study assessed the compounding hydrologic effects of increased irrigation pumping during drought years (2010–2012) on stream–aquifer water exchange (stream–aquifer flux) between the Flint River and UFA using the United States Geological Survey modular finite element groundwater flow model. Principal component and K‐means clustering analyses were used to identify critical stream reaches and tributaries that are adversely affected by irrigation pumping. Additionally, the effectiveness of possible water restriction scenarios on stream–aquifer flux was also analysed. Moreover, a cost–benefit analysis of acreage buyout procedure was conducted for various water restriction scenarios. Results indicate that increased groundwater withdrawal in Water Year 2011 decreased baseflow in the lower Apalachicola–Chattahoochee–Flint River Basin, particularly, in Spring Creek, where irrigation pumping during April, June, and July changed the creek condition from a gaining to losing stream. Results from sensitivity analysis and simulated water restrictions suggest that reducing pumping in selected sensitive areas is more effective in streamflow recovery (approximately 78%) than is reducing irrigation intensity by a prescribed percentage of current pumping rates, such as 15% or 30%, throughout the basin. Moreover, analysis of acreage buyout indicates that restrictions on irrigation withdrawal can have significant impacts on stream–aquifer flux in the Basin, especially in critical watersheds such as Spring and Ichawaynochaway Creeks. The proposed procedure for ranking of stream reaches (sensitivity analysis) in this study can be replicated in other study areas/models. This study provides useful information to policymakers for devising alternate irrigation water withdrawal policies during droughts for maintaining flow levels in the study area.

Evaluating Baseflow Simulation in the National Water Model: A Case Study in the Northern High Plains Region, USA

“…Also, evaluation of all separation methods available in the toolbox for baseflow estimation showed comparable results in a study performed by Borchardt et al (2016). These methods have been, however, used in multiple hydrological modeling studies as an estimate for groundwater flow (baseflow) into streams (Arnold et al 2000; Peterson et al 2016; Singh et al 2017), and are therefore the best relativistic comparison for testing baseflow simulated by the NWM.…”

Multivariate Assimilation of Remotely Sensed Soil Moisture and Evapotranspiration for Drought Monitoring

“…These two rivers merge at Lake Seminole to form the Apalachicola River, which drains into the Apalachicola Bay and the Gulf of Mexico. The region has undergone extensive irrigation expansion between the 1970s and 1980s (Singh et al 2017). Irrigated farmlands make up 452 000 acres within the region, making the area susceptible to huge economical losses during drought periods.…”

Effects of Soil–Rock Geomorphic Units on the Yield of Surface Runoff: A Case Study on Uncultivated Land of a Karst Area

“…In general, the karst landform contributes less to surface runoff, and this causes a temporary drought in the surface soil and a serious shortage of water for agricultural irrigation. Water is the key to solving the area's problems, and it is therefore important to study the processes and characteristics of water movement in karstic rocky desertification areas [29][30][31]. However, the current research on karst hydrology generally pays attention to the large scale, such as a region or watershed [32][33][34], and there are few reports on a microscale, especially on soil-rock combination microgeomorphic units, and the contribution of soil and rock to surface runoff is unclear.…”