||Irrigation return flow water quality monitoring, modeling and variability in the middle Rio Grande Valley, New Mexico /
Gelhar, L. W. ;
Wierenga, P. J. ;
Rehfeldt, K. R. ;
Duffy, C. J. ;
Simonett, M. J.
||New Mexico Inst. of Mining and Technology, Socorro. ;New Mexico State Univ., Las Cruces. Dept. of Agronomy.;Robert S. Kerr Environmental Research Lab., Ada, OK.
|| Robert S. Kerr Environmental Research Laboratory, Office of Research and Development, U.S. Environmental Protection Agency ; [Available from the National Technical Information Service],
Irrigation--Environmental aspects--New Mexico--Rio Grande Valley. ;
Salinity--New Mexico--Rio Grande Valley. ;
Agricultural chemicals--New Mexico--Rio Grande Valley--Pollution. ;
Groundwater--Pollution--New Mexico--Rio Grande Valley. ;
Groundwater flow--New Mexico--Rio Grande Valley--Mathematical models. ;
Agricultural chemicals--Pollution--New Mexico--Rio Grande Valley ;
Water, Underground--Pollution--New Mexico--Rio Grande Valley
Water pollution ;
Rio Grande Valley ;
Subsurface drainage ;
Ground water ;
Mathematical models ;
Fluid flow ;
Corn plants ;
Inorganic nitrates ;
New Mexico ;
Irrigation efficiency ;
||Most EPA libraries have a fiche copy filed under the call number shown. Check with individual libraries about paper copy.
||xxi, 492 pages : illustrations ; 28 cm
A 250-acre (100 hectare) irrigated farm in the middle Rio Grande valley at San Acacia, New Mexico, was intensively monitored for the five year period from 1977 through 1982. During that time there was no statistically significant change in the total dissolved solids concentration in the shallow groundwater underlying the site. Upwelling of water from a deep, high-salinity regional aquifer is the probable source of a majority of the salinity observed in the drains. A significant increase in nitrate concentration in the drains and shallow groundwater was observed as portions of the farm were converted from alfalfa to corn. Analyses of extensive, systematic measurements of the spatial variability of chemical and physical parameters gave spatial correlation scales on the order of 10 meters in the horizontal direction and less than 1 meter in the vertical. Major weekly chemical variations were observed in the irrigation water, groundwater, and drains. Two computer-based models were used to simulate the flow and water quality behavior. A two-cell lumped parameter model adequately simulated the average monthly drain water chloride concentration.
"September 1983." "Grant No. R-806092." "PB83-261719." Includes bibliographical references (pages 220-221). Photocopy.