Water Quality Assessment Rio Conchos By Dr. Melida Gutierrez Visiting Professor from Southern Missouri State University
The Chihuahuan Desert The Chihuahuan Desert is approximately 800 miles long and 250 miles wide. Included in the region are parts of the states of Arizona, New Mexico, and Texas. Chihuahua, Coahuila, Nuevo Leon, Durango, Zacatecas, and San Luis Potosi in Mexico. Elevation and Climate: Although the Chihuahuan Desert region extends farther south than other North American deserts, extensive portions lie above 4,000 ft. in elevation. The lowest portions of the Chihuahuan Desert region are about 1000 ft. in elevation along the Rio Grande while the highest portions, in Mexico, approach 10,000 ft. in elevation
Sampling Locations 1997 (about 100) H C B A Rio Conchos Basin
Water Quality Study, 1997 105 water samples 10 sediment samples ph, electrical conductivity Nitrates, phosphates, and 64 elements (21 found below detection limits, ICP-mass spectrometer) No anions (sulfates, chlorides) No data was available for comparing values
Results: a concentration pattern for each element Sampling points included river and incoming flows Sampling locations not evenly distributed
Elements following each concentration pattern: Ca (concentrations increase downstream): Ca, K, Ge, Sr, Cd, Ba, La Na (concentrations reach a maximum at end of segment B, where irrigation is extensive): Na, Li, Be, B, Mg, Al, V, Cr, Mn, Fe, Cu, As, Se, Rb, Zr, Mo, Pd, Ce, Hf, U. Pb (highest concentration at end of segment A): Pb, W, Au, Hg, Nd, Ta Ni (no pattern): Ni, Zn, Ti, Co, Ag, Cs, Th.
Drastic change in water chemistry occurs in this area Rio Conchos Basin
There is a need for background data Why? There are not enough data for this area The Conchos is one of the largest tributaries of the Rio Grande; it supplies >75% of water in the Rio Grande at its confluence Region (central Chihuahua) is growing in population, services and industry. Wildlife protection is imperative Results could be applicable to other parts of the Chihuahuan desert or other semi-arid regions.
Study Area: Rio Conchos near El Granero Reservoir Last reservoir before the river joins the Rio Grande Water quality changes Wildlife abundant; riparian zone is an important source for habitat and food Potential use as drinking water source for the city of Chihuahua?
Contribution by Springs Location/Time of sampling SC TDS Ca+2 Na+ HCO 3 - SO 4-2 Cl- µs/cm mg/l ppm ppm ppm ppm ppm Spring Chorreras Jun. 1983 640 432 48 63 152 94 57 Oct. 2001 614 n.d. 62 53 n.d. n.d. n.d. Spring El Atascadero Jun. 1983 930 556 38 110 183 104 99 Spring Las Minas Jun. 1983 1,050 700 43 73 207 292 21 Spring (no-name)* Jun. 1983 3,200 2,748 508 75 256 294 291 Río Conchos (El Potrero) Jun. 1983 1,460 891 44 187 207 355 60 Oct. 2001 2,460 n.d. 149 342 n.d. n.d. n.d. Shallow well (El Potrero) Jun. 1983 2,190 1,416 110 314 256 563 142 Oct. 2001 2,160 n.d. 164 272 n.d. n.d. n.d. Luis L. León Reservoir Jun. 1983 1,450 863 42 183 189 344 67 Jun. 1997 1,054 n.d. 67 118 n.d. n.d. n.d.
Geology of the area granodiorite shale Limestone limestone Rhyolite Conglomerate conglomerate alluvium Limestone w/gypsum rhyolite limestone w/gypsum Alluvium
Almost the perfect research area Unique location due to: Undisturbed land (no irrigation, sparsely populated, mostly native vegetation, some springs) Unique geology, wide variety of rock outcrops; salt deposits (playa lakes) in nearby closed-drainage basins Several different types of salts/types of soils are expected, which provides a (challenging) way to test the separability among salt- and sodium-affected soils. Relatively distant (100 km) highly utilized land (urban, agriculture, industrial) can be used to test the effectiveness of natural cleansing processes
How much of the area will look like this in the future? Salt affected parcels by Meoqui: how much of them are natural and how much irrigation-induced?
Salinity trends for the Rio Conchos near Ojinaga, 1980-1998 3500 Ene-Mar 3000 Abr-Jun 2500 Jul-Sep Oct-Dic y = 29.006x - 1084.4 R 2 = 0.2004 y = 14.913x + 91.321 R 2 = 0.0151 2000 µs/cm 1500 1000 y = 15.047x - 64.114 R 2 = 0.0274 500 y = 27.095x - 949.47 R 2 = 0.0989 0 79 81 83 85 87 89 91 93 95 97 99
Salinity of the river water is increasing So what? What can be done? Determine the sources Determine the variations with time Determine the mineralogy/geochemistry Once the above are known, a control and method can be developed which includes preventive and corrective measurements, disposal of brine, regulatory policies, etc.
Work published/presented Gutiérrez, M. and E. Carreón, submitted. Salinidad en el bajo río Conchos: Tendencias y aportes, Terra (Journal of the Mexican Soil Association). Gutiérrez, M., K. Mickus, and E. Johnson, 2004. Watershed Assessment Along a Segment of the Rio Conchos in Northern Mexico Using Satellite Images, Journal of Arid Environments, 56, 395-412. Gutiérrez, M. 2000. Trace Element Concentration Patterns in Sediments of the Lower Rio Conchos, Mexico. Water, Air and Soil Pollution. 121, 259-270. Gutiérrez, M. and P. Borrego. 1999. Water Quality Assessment of the Rio Conchos, Chihuahua, Mexico. Journal of Environment International, 25, 573-583 Gutiérrez, M. Geologic Factors Influencing the Water Chemistry of a Segment of the Lower Rio Conchos, Chihuahua. Unión Geofísica Mexicana, Puerto Vallarta, Mexico, 2001, GEOS, 21, p. 228. Gutiérrez, M. and E. Johnson. Inferring the Origin of a Salt Crust Over Saline Soils by its Chemical Parameters. Geological Society of America, Albuquerque, NM, 2001. Johnson E., M. Gutiérrez, and K. Mickus. Evaluation of Pollution Sources for a Segment of the Rio Conchos in Northern Mexico by Use of Landsat TM. Am. Soc. of Photogrammetry and Remote Sensing, St. Louis, MO, 2001.
Basin management. much is water politics www.diario.com.mx/ then click Delicias News include at least one daily note on water issues: farmers concerns, reservoir levels, water policy. constant struggles!!
The latest: electricity cuts for well pumps Rio San Pedro.. Where is it? Who took it? March 8, 2004 March 10, 2004
Recent reports on the Rio Bravo&Conchos Kelly, 2001. The Rio Conchos: A Preliminary Overview. Texas Center for Policy Studies, http://www.texascenter.org/publications/rioconchos.pdf HARC, 2000. Water and Sustainable Development in the Binational Lower Rio Grande/Rio Bravo Basin. Houston Advance Research Center and ITESM (Mexico), Center for Global Studies, Woodland, Texas, 1045 pp. INEGI. 1999. Estudio Hidrológico del Estado de Chihuahua. Aguascalientes, 244 pp. IBWC, 1994. Binational Study Regarding the Presence of Toxic Substances in the Rio Grande /Río Bravo and its Tributaries Along the Boundary Portion Between the United States and Mexico. International Water and Boundary Commission, El Paso, Texas, 246 pp. have stirred interest from Mexican scientists to participate in research projects: UACH, UACJ, Instituto de la Sequía, INIFAP CONACYT awarded in 2004 a grant for a three-year water quality study of the Conchos Basin to a former UACH investigator, Dr. H. Rubio (INIFAP), also shows that Mexican agencies are more willing to participate in international collaboration research efforts.
Additional research possibilities include Effects of deforestation in the Sierra Madre on water quality and soil erosion Watershed management practices that will ensure water supply (sustainable use) Effects of sewage/primary treated water on crops and river quality Long-term crop management for a best utilization of water and soil resources Safe utilization of treated water for public parks in urban settings Water savings by large-scale greenhouse utilization Monitoring of water table levels of aquifers fed by the Rio Conchos Monitoring of riparian vegetation abundance and vitality Wildlife inventory; Protection of endangered species (habitat)
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