Journal of the Arkansas Academy of Science Volume 58 Article 6 2004 Tailwater Recovery Systems for Irrigation: Benefit/ Cost Analysis and Water Resource Conservation Technique in Northeast Arkansas Jennifer L. Bouldin Arkansas State University Nate A. Bickford Arkansas State University H. B. Stroud Arkansas State University G. S. Guha Arkansas State University Follow this and additional works at: http://scholarworks.uark.edu/jaas Part of the Fresh Water Studies Commons, and the Water Resource Management Commons Recommended Citation Bouldin, Jennifer L.; Bickford, Nate A.; Stroud, H. B.; and Guha, G. S. (2004) "Tailwater Recovery Systems for Irrigation: Benefit/ Cost Analysis and Water Resource Conservation Technique in Northeast Arkansas," Journal of the Arkansas Academy of Science: Vol. 58 , Article 6. Available at: http://scholarworks.uark.edu/jaas/vol58/iss1/6 This article is available for use under the Creative Commons license: Attribution-NoDerivatives 4.0 International (CC BY-ND 4.0). Users are able to read, download, copy, print, distribute, search, link to the full texts of these articles, or use them for any other lawful purpose, without asking prior permission from the publisher or the author. This Article is brought to you for free and open access by ScholarWorks@UARK. It has been accepted for inclusion in Journal of the Arkansas Academy of Science by an authorized editor of ScholarWorks@UARK. For more information, please contact [email protected]. * Journal of the Arkansas Academy of Science, Vol. 58 [2004], Art. 6 Tailwater Recovery Systems for Irrigation: Benefit/Cost Analysis and Water Resource Conservation Technique inNortheast Arkansas J.L. Bouldin*,N.A.Bickford, H.B. Stroud and G.S. Guha Arkansas State University Environmental Sciences Ph.D. Program P.O. Box 847 State University, AR 72467 *Corresponding author Abstract Water, one ofthe earth's most vital resources, is particularly significant in the Arkansas Delta agricultural landscape. While both surface and groundwater are extremely important, 94% of the 26.9 billionL (7.1 billiongal) of water pumped daily from the AlluvialAquifer is used for agricultural purposes. This common property is subsequently being depleted and sustainable conservation methods are being pursued. State and federal incentive programs encourage the use of a tailwater recovery system inagricultural irrigation. With the use of a complete recovery system, benefits include not only government incentives for wetland habitat, but reduced groundwater use and decreased agricultural runoff entering receiving streams. Costs incurred to the farm manager include crop loss due to reservoir storage, additional ditch construction, and the cost of a liftpump. Use of these systems offers not only economic benefits associated with aquifer preservation but also ecological benefits including reduced nutrient and sediment loading to receiving streams concurrent with ecosystem services. The overall benefit/cost analysis ofthese systems shows that the economic benefits of using a tailwater recovery system exceed the cost. Other positive features include the ecological benefits of surface water protection and ecosystem services. Introduction water for each kg (228 gal/lb) produced and soybeans requiring 2,000 L of water for each kg produced (238 Surface water uses in Arkansas include navigation for gal/lb). shipment of goods on the Arkansas and White rivers, The National Agriculture Statistics Service (NASS, withdrawal for public water supply, and discharge for 2003) states that Arkansas was the largest producer ofrice in municipality, industry and agricultural waste, and limited the United States, producing 4.35 billionkg (9.6 billion lb) rrigation for agriculture (Arkansas Environmental in 2002. In this year, the state supported 5.91 million ha federation (AEF), 2003). Although there are a variety of (14.6 million acres) of crop production with 1.50 million of uses for surface water, 73% of the total water used in the those ha (3.7 million acres) under irrigation. Total irrigated tate is groundwater, making Arkansas the fourth largest acres in northeast Arkansas included 89,702 ha (221,658 user of groundwater in the nation (ASWCC, 2004). It acres) in Craighead County with 31,970 and 29.495 ha hould also be noted that two areas of the state have been (79,000 and 63,000 acres) respectively inrice and irrigated declared critical with regard to groundwater, including a soybean production. NASS reported a total of 47,100 egion of south-central Arkansas and an area in east-central irrigated ha (116,388 acres) for Greene County, with24,848 Arkansas that are experiencing depletion of the Sparta and 20,235 ha (61,400 and 50,000 acres) inrice and irrigated Aquifer and the Sparta and Alluvial aquifers, respectively. soybean production. For the same year, Poinsett County Groundwater is also used by municipalities, as a drinking supported 110,895 irrigated ha (274,028 acres) with 54,673 water source, as well as fire protection. Inaddition, industry and 46,944 ha (135,100 and 116,000 acres) in rice and s attracted to water rich areas and often uses large quantities irrigated soybean production. This extensive production of water in on-line processing and cooling. acreage in northeast Arkansas illustrates how water As the largest user of water in the state, agriculture is availability and fertile soils combine to make Arkansas the dependent upon this resource for the application of fourth largest user of groundwater in the nation (AEF, ertilizers and pesticides and the irrigation ofstanding crops. 2003). Water is also utilized as a physical herbicide in rice The Mississippi River Valley Alluvial Aquifer is the )roduction, minimizing chemical application. Pimentel et surficial aquifer system located beneath the eastern one- al. (2000) reported that rice and soybeans are among the third of Arkansas (Fig. 1). Large groundwater withdrawals most water demanding crops, with rice requiring 1,910 Lof from this aquifer have resulted in a long-term decline of Journal of the Arkansas Academy of Science, Vol. 58, 2004 Published by Arkansas Academy of Science, 2004 23 23 Journal of the Arkansas Academy of Science, Vol. 58 [2004], Art. 6 Tailwater Recovery Systems for Irrigation:Benefit/Cost Analysis and Water Resource Conservation Technique inNortheast Arkansas EXPLANATION Thickness ofaqwfer, in feet 23 to 50 50 to 75 75 to 100 100 «0 150 QtMttrthan 150 BA* Uimi offcydrojcotojic A Base modified from U.S. Geologic*!Survey digital data, 1 2,000,000, 1972 Modifiedfrom Ackerman, DJ ,1996, HydrologyOfthe Mississippi River Valtey alluvial aquifer, south- centra! United States: U.S. Geological Survey Professional Paper 1416-0, 56 p Fig. 1. Location and thickness of the Mississippi River Valley AlluvialAquifer as reported byUSGS. water levels in some areas and also have reduced the groundwater per day were extracted in 2001 from the state's amount of water discharged into rivers. By the early 1980s, aquifers. Currently, the same volume of water is extracted withdrawal for irrigation and aquaculture had dropped daily from the Alluvial Aquifer for use in Arkansas, with water levels in the AlluvialAquifer below the stream bed of 94% used by agriculture (Fig. 2) (ASWCC, 2004). Since several rivers that have acted as long term drains from the 1996, the aquifer has fallen an average of 0.30 m(one ft) per aquifer (Renken, 1998). The configuration of the water table year with Craighead County's five-year (1996-2001) decline near rivers that incise the Mississippi River Valley Alluvial equivalent to 1.12 m (3.69 ft). This county is flanked with a Aquifer is influenced by seasonal changes in river stage 1.84 and 1.23-m (6.03 and 4.05-ft) decline, respectively, in (USGS, 2002). During the winter and spring, greater stream Poinsett and Greene counties for the same five-year period flow characterizes the rivers as influent, recharging the (ASWCC, 2004). In 2002 the Arkansas Water Resources aquifer and raising the water table. However, during the Center reported that over the next 30-year period the dryer seasons of summer and fall, stream flow is low, and Alluvial Aquifer would fall to critical levels, leaving most groundwater from the aquifer is discharged into the river. irrigated farms without operational wells. Groundwater use These seasonal changes in water levels in the Alluvial and uncertain aquifer levels in Arkansas have raised Aquifer may be quite large. According toRenken (1998) the concern by state officials and policy makers, calling for decline in water levels in the Mississippi River Valley conservation methods by the agricultural community and AlluvialAquifer from spring to fall, 1965, was greater than legislation encouraging alternate plans for water utilization. 3.05 meters (10 feet) in some areas. The seasonal influx Government incentives and payback enticements are now makes the alluvial aquifer a renewable resource, albeit at a available to encourage these management practices. very sluggish rate. However, the natural recharge of this The reuse of irrigation water from agricultural fields resource cannot compensate for the constant demands of targeted for discharge into receiving streams is defined as groundwater withdrawals. tailwater recovery. Capture techniques vary according to Approximately 26.9 billion L (7.1 billion gal) of source waters used; these include groundwater, surface Journal of the Arkansas Academy of Science, Vol. 58, 2004 http://scholarworks.uark.edu/jaas/vol58/iss1/6 24 24 1 Journal of the Arkansas Academy of Science, Vol. 58 [2004], Art. 6 J.L. Bouldin, N.A. Bickford, H.B. Stroud and G.S. Guha Commercial Aquaculture ° Public supply J 6% Irrigation 84% Fig 2. Groundwater use from the Mississippi River Valley Alluvial Aquifer during 1995 as reported by USGS water from rivers, streams, and runoff. Storage reservoirs of gills, and transport of sediment-bound contaminants (US hold water that is then utilized for irrigation. Irrigation EPA, 2002). Turbidity caused by erosion is often associated water is then recaptured following release from flooded with additional contaminants, such as nutrients, pathogens, fields and redirected to the reservoir for future reuse.