Impact of agroecosystems on groundwater resources in the Central High Plains, USA

Abstract Agroecosystems impact water resources by consuming most fresh water through irrigation and by changing water partitioning at the land surface. The study assesses impacts of agroecosystems on groundwater resources in the Texas Central High Plains (37,000 km 2 area) by evaluating temporal variations in groundwater storage and quality. Percolation/recharge rates were estimated using groundwater Cl data and using unsaturated zone matric potential and water-extractable chloride and nitrate from 33 boreholes beneath different agroecosystems. Total groundwater storage decreased by 57 km 3 since the 1950s when irrigation began and individual well hydrographs had declines ≤1.3 m/yr. The renewable portion of groundwater is controlled by percolation/recharge, which is related to soil texture and land use. In fine–medium (f–m) grained soils, there is no recharge beneath natural ecosystems or rain-fed agroecosystems; however, recharge is focused beneath playas and drainages. In medium–coarse (m–c) grained soils, percolation/recharge is low (median 4.8 mm/yr) beneath natural ecosystems and is moderate (median 27 mm/yr) beneath rain-fed agroecosystems. Although irrigation increased percolation under all soil types (median 37 mm/yr), irrigation return flow has not recharged the aquifer in most areas because of deep water tables. Groundwater depletion (21 km 3 over 52 yr) is 10 times greater than recharge (11 mm/yr; 2.1 km 3 ) where water table declines are greatest (≥30 m). Therefore, current irrigation practices are not sustainable and constitute mining of the aquifer, which is being managed as a nonrenewable resource.

[1]  B. Scanlon,et al.  Assessing controls on diffuse groundwater recharge using unsaturated flow modeling , 2005 .

[2]  R. Reedy,et al.  Effects of irrigated agroecosystems: 1. Quantity of soil water and groundwater in the southern High Plains, Texas , 2010 .

[3]  J. Lenters,et al.  On the role of groundwater and soil texture in the regional water balance: An investigation of the Nebraska Sand Hills, USA , 2009 .

[4]  Jason J. Gurdak,et al.  Storage and transit time of chemicals in thick unsaturated zones under rangeland and irrigated cropland, High Plains, United States , 2006 .

[5]  Marios Sophocleous,et al.  Groundwater recharge estimation and regionalization: the Great Bend Prairie of central Kansas and its recharge statistics , 1992 .

[6]  B. Scanlon,et al.  Effects of irrigated agroecosystems: 2. Quality of soil water and groundwater in the southern High Plains, Texas , 2010 .

[7]  P. Gowda,et al.  Irrigation in the Texas High Plains: a brief history and potential reductions in demand , 2009 .

[8]  P. Cook,et al.  Using groundwater levels to estimate recharge , 2002 .

[9]  Jason J. Gurdak,et al.  Ground-water quality beneath irrigated agriculture in the central High Plains aquifer, 1999-2000 , 2003 .

[10]  Marios Sophocleous,et al.  Combining the soilwater balance and water-level fluctuation methods to estimate natural groundwater recharge: Practical aspects , 1991 .

[11]  R. Reedy,et al.  Impacts of land use change on nitrogen cycling archived in semiarid unsaturated zone nitrate profiles, southern High Plains, Texas. , 2008, Environmental science & technology.

[12]  R. Reedy,et al.  Impact of deep plowing on groundwater recharge in a semiarid region: Case study, High Plains, Texas , 2008 .

[13]  R. Reedy,et al.  Inventories and mobilization of unsaturated zone sulfate, fluoride, and chloride related to land use change in semiarid regions, southwestern United States and Australia , 2009 .

[14]  D. Whittemore,et al.  Uses of Chloride/Bromide Ratios in Studies of Potable Water , 1998 .

[15]  J. Wickham,et al.  Completion of the 2001 National Land Cover Database for the conterminous United States , 2007 .

[16]  S. Massuel,et al.  Land clearing, climate variability, and water resources increase in semiarid southwest Niger: A review , 2009 .

[17]  Sharon L. Qi,et al.  Classification of irrigated land using satellite imagery, the High Plains aquifer, nominal date 1992 , 2002 .

[18]  Sharon L. Qi,et al.  Vulnerability of recently recharged ground water in the High Plains aquifer to nitrate contamination , 2006 .

[19]  M. Becker,et al.  Hydrogeology, water use, and simulation of flow in the High Plains aquifer in northwestern Oklahoma, southeastern Colorado, southwestern Kansas, northeastern New Mexico, and northwestern Texas , 1999 .

[20]  R. Reedy,et al.  Variations in flow and transport in thick desert vadose zones in response to paleoclimatic forcing (0–90 kyr): Field measurements, modeling, and uncertainties , 2003 .

[21]  B. Scanlon,et al.  Field study of spatial variability in unsaturated flow beneath and adjacent to playas , 1997 .

[22]  G. B. Allison,et al.  The use of natural tracers as indicators of soil-water movement in a temperate semi-arid region , 1983 .

[23]  V. Holliday,et al.  Evidence of Active Dune Sand on the Great Plains in the 19th Century from Accounts of Early Explorers , 1995, Quaternary Research.

[24]  Nancy L. Barber,et al.  Estimated withdrawals from principal aquifers in the United States, 2000 , 2005 .

[25]  John Karl Böhlke,et al.  Geochemistry, radiocarbon ages, and paleorecharge conditions along a transect in the central High Plains aquifer, southwestern Kansas, USA , 2004 .

[26]  V. Holliday,et al.  Eolian sedimentation and soil development on a semiarid to subhumid grassland, Tertiary Ogallala and Quaternary Blackwater Draw Formations, Texas and New Mexico High Plains , 1999 .

[27]  Rodger B. Grayson,et al.  Towards a framework for predicting impacts of land-use on recharge: 1. A review of recharge studies in Australia , 2002 .

[28]  P. Cook,et al.  A new chloride leaching approach to the estimation of diffuse recharge following a change in land use , 1991 .

[29]  Christopher A. Barnes,et al.  Completion of the 2006 National Land Cover Database for the conterminous United States. , 2011 .

[30]  A. Flint,et al.  Artificial Recharge Through a Thick, Heterogeneous Unsaturated Zone , 2008, Ground water.

[31]  D. Stonestrom,et al.  Estimates of deep percolation beneath native vegetation, irrigated fields, and the Amargosa-River Channel, Amargosa Desert, Nye County, Nevada , 2003 .

[32]  Petra Döll,et al.  Development and validation of the global map of irrigation areas , 2005 .

[33]  Glen R. Walker,et al.  Land clearance and river salinisation in the western Murray Basin, Australia , 1990 .

[34]  R. Reedy,et al.  Semiarid unsaturated zone chloride profiles: Archives of past land use change impacts on water resources in the southern High Plains, United States , 2007 .

[35]  W. W. Wood,et al.  Chemical and Isotopic Methods for Quantifying Ground‐Water Recharge in a Regional, Semiarid Environment , 1995 .

[36]  M. Sophocleous,et al.  Water movement through thick unsaturated zones overlying the central High Plains aquifer, southwestern Kansas, 2000-2001 , 2003 .

[37]  J. Banner,et al.  Controls on the regional-scale salinization of the Ogallala aquifer, Southern High Plains, Texas, USA , 2000 .

[38]  Glen R. Walker,et al.  Factors affecting groundwater recharge following clearing in the south western Murray Basin , 1994 .

[39]  V. L. McGuire.  Water-Level Changes in the High Plains Aquifer, Predevelopment to 2007, 2005-06, and 2006-07 , 2009 .

[40]  I. Shiklomanov.  Appraisal and Assessment of World Water Resources , 2000 .