|
History of Streamflow and Suspended-Sediment Collection in the Rio Puerco Basin, New Mexico Allen Gellis, U.S. Geological Survey, Albuquerque, NM 87110
The high sediment loads and sediment transport characteristics of the Rio Puerco, central New Mexico, have for decades attracted the attention of geologists, hydrologists, and engineers (Bryan and Post, 1927; Nordin and Curtis, 1962; Nordin, 1963; Heath, 1983; Gellis,1992). Suspended-sediment concentrations in excess of 400,000 ppm were observed by Nordin (1963) for the Rio Puerco near Bernardo and averages of 79,000 mg/L were reported by the Bureau of Reclamation (1994). Simons and others (1991) estimated that 90 percent of the suspended-sediment load in the Rio Puerco is silt and clay (<0.062mm). The problems caused by the transport of this sediment into the Rio Grande has been a concern since the 1920's when Bryan and Post (1927) outlined a detailed plan to control erosion and sediment transport in the Rio Puerco. In response to continuing problems of sedimentation in Elephant Butte Reservoir and the Rio Grande, the Bureau of Reclamation, in 1994, investigated the development of a sediment control project for the Rio Puerco (Bureau of Reclamation, 1994). The drainage area of the Rio Puerco located in central New Mexico is 7,350 mi2 (19,036 km2) of which 1,130 mi2 (2,927 km2) does not contribute to surface runoff (fig. 1). The Rio Puerco is intermittent through most of its length with higher elevations receiving snowmelt and precipitation runoff events and lower reaches dominated by convective rainfall-runoff events. The large aerial extent of erosive geologic units in the basin provides a large source of available sediment to the channel. Happ (1948) estimated the sources of sediment in the Rio Puerco as: 40% erosion of the existing Rio Puerco channel (bed and banks), 30% erosion in tributary channels, and 30% sheet, rill, and minor gully erosion.
For the period of suspended-sediment collection at the Rio Puerco near Bernardo, 1948-96, the average annual suspended-sediment load was 4.44 million tons (4.03 metric tons). The sediment yield of the Rio Puerco is moderately high compared to world rivers (fig. 2a). However, by normalizing sediment load by average annual runoff instead of drainage area the Rio Puerco has the third highest sediment concentration (fig. 2b). Compared to the suspended-sediment loads transported at the Rio Grande near San Marcia, located approximately 52 miles (84 km) downstream of the Rio Puerco, the Rio Puerco transported 83% of the total load of the Rio Grande from 1948 to 1973 and 64% of the total load from 1974 to 1996. For the same periods, 1948-73 and 1974-96, the Rio Puerco transported 5.6 and 2.3%, respectively, of the total runoff measured at the Rio Grande near San Marcia. In 1974, Cochiti Reservoir located approximately 92 miles (148 km) upstream from the mouth of the Rio Puerco, was closed and therefore, 1974 was chosen as a break in the two time periods. The closure of Cochiti Reservoir may have reduced the upstream contributions of sediment and therefore, may have effected downstream sediment transport. During the period of sediment collection at the five stations (fig. 1) most of the runoff (30 to 50%) occurs in August or September (fig. 3a). Rainfall events during the monsoonal period in New Mexico from July to September are typical of convective-type rainfall events. The station Rio Puerco above Arroyo Chico has peak runoff in May and is a function of snowmelt in the Nacimiento Mountains above Cuba. Thirty-one to 51 percent of the suspended-sediment load at the five stations is transported during the monsoonal period in August or September (fig. 3b). A sediment budget for the Rio Puerco was developed using suspended-sediment data from these five stations from 1949 to 1955 (fig. 1). Compared to the Rio Puerco near Bernardo, the largest upstream contributor of suspended sediment from 1949 to 1955, is the Arroyo Chico which drains 24 percent of the basin and delivers 34 percent of the suspended-sediment load (fig. 4). The Arroyo Chico also contributed most of the runoff (52%). The highest average annual sediment yield of any station is the Rio Puerco above Arroyo Chico (2,721 tons/mi²). The highest total sediment concentration of any station, reported as total suspended sediment for the period divided by total runoff, is the Rio Puerco above Arroyo Chico (190 tons sediment/acre-feet runoff). The Rio San Jose at Correo reported the lowest values on sediment transport of any station (fig. 4). This low value of suspended-sediment transported at the Rio San Jose near Correo relative to the main stem Rio Puerco and Arroyo Chico may reflect differences in geology, soils, and channel hydraulics.
Elliott (1979) distinguished downstream channel reaches from upstream reaches based on multiple discriminant function analyses of selected channel geometric, sedimentologic, and planimetric variables. Upstream channel reaches had large width-to-depth ratios, contained relatively small amounts of silt and clay sized material in the channel perimeter, contained low vegetation density, and a lateral shifting channel that was actively eroding. The channel in the downstream reaches had relatively small width-to-depth ratios, large amounts of silt and clay sized material in the channel perimeter, high vegetation density, and a relatively stable channel position. According to Elliott (1979), the 1930's lower Rio Puerco channel was similar to the 1977 upstream reaches and led Elliott to conclude that channel stabilization was progressing from downstream to upstream reaches. Resurveys of the 1977 cross sections in 1994 to 1997 by Elliott and others (1998), reaffirmed this earlier hypothesis. Channel changes were continuing in the upper reaches of the Rio Puerco where decreasing width-to-depth ratios were observed. Love (1997) attributed the decrease in suspended-sediment loads at the Rio Puerco to a decrease in annual peak flows since the 1930's (fig. 6). The decrease in peak flows coupled with the planting of tamarisk led to an increase in vegetation on the floodplain. The increased vegetation led to an increase in roughness, increase in sediment deposition, and a decrease in suspended-sediment loads. Further research may indicate whether the decrease in peak flows is due to climate (rainfall and rainfall intensity) or to changes in channel cross-sectional and planform geometry. Another possible explanation for the decrease in suspended-sediment loads may include successful land-management treatments in reducing erosion implemented by various land-management agencies in the Rio Puerco basin. The Bureau of Land Management, National Resource Conservation Service, Bureau of Indian Affairs, and other agencies have been implementing programs to reduce erosion and improve vegetation cover in the Rio Puerco since the 1930's (Burkham, 1966; Soil Conservation Service, 1977). However, the success of these programs is often not monitored and quantified. The lack of monitoring of erosion-control structures has not been limited to the Rio Puerco but is a problem present throughout the Southwest. For example, a lack of project documentation, monitoring, and evaluation of watershed and riparian treatments was documented for the U.S. Forest Service southwestern region (Ahlborn and others, 1992). Gellis and others (1995) noted a similar lack of project documentation, maintenance, and monitoring for erosion-control structures built on the Zuni Indian Reservation, New Mexico.
Conclusions
A decrease in suspended-sediment loads over time is observed at three stations in the Rio Puerco with long periods of record, the Rio Puerco near Bernardo, the Rio Puerco above Arroyo Chico, and the Arroyo Chico near Guadalupe. The decrease in sediment loads may be due to changes in channel and planform geometry of the Rio Puerco or to a decrease in peak flows. Both explanations favor an increase in vegetation, which leads to an increase in channel roughness and an increase in sediment deposition. It is also possible that the decrease in sediment loads is due to successful upland erosion-control strategies implemented over time by various land-management agencies. The success of many of these strategies has not been monitored or quantified.
References
Bryan, K.B., and Post, G.M., 1927, Erosion and control of silt on the Rio Puerco, New Mexico: Unpublished report to the Chief Engineer, Middle Rio Grande Conservancy District Albuquerque, N.M., October. 1927, 133 p. Bureau of Reclamation, 1994, Rio Puerco sedimentation and water quality study: U.S. Bureau of Reclamation Preliminary Findings Report, 47 p. Burkham, D.E., 1966, Hydrology of Cornfield Wash area and effects of land-treatment practices, Sandoval County New Mexico, 1951-60: U.S. Geological Survey Water-Supply Paper 1831, 87pp. Edwards, T.K., and Glysson, G.D., 1988, Field methods for measurement of fluvial sediment: U.S. Geological Survey Open-File Report 86-531, 118 p. Elliott, J.G., 1979, Evolution of large arroyos--The Rio Puerco of New Mexico: Unpublished Master's Thesis, Colorado State university, Fort Collins. Elliott, J.G., Gellis, A.C., and Aby, S.B., 1998, Evolution of Arroyos--Incised Channels of the Southwestern United States: In Thorne, C., ed., Incised Channels, IN PRESS. Gellis, A.C., Hereford, R., Schumm, S.A., and Hayes, B.R., 1991, Channel evolution and hydrologic variations in the Colorado River basin--Factors influencing sediment and salt loads: Journal of Hydrology, v. 124, p. 317-344. Gellis, A.C., 1992, Decreasing trends of suspended-sediment loads in selected streamflow stations in New Mexico: New Mexico Water Resources Research Institute Report No. 265, Proceedings of the 36th Annual New Mexico Water Conference, Las Cruces, N.Mex., p. 77-93. Gellis, A.C., Cheama, A., Laahty, V., and Lalio, S., 1995, Assessment of gully-control structures in the Rio Nutria watershed, Zuni Reservation, New Mexico: Water Resources Bulletin, v. 31, no. 4, p. 633-646. Happ, S.C., 1948, Sedimentation in the Rio Grande valley, New Mexico: U.S. Department of Agriculture, Soil Conservation Service Report. Heath, D.L., 1983, Flood and recharge relationships of the lower Rio Puerco, New Mexico: New Mexico Geological Society Guidebook, 34th Field Conference, Socorro Region II, p. 329-337. Kondolf, G.M., Matthews W.V. G., 1991, Unmeasured Residuals in Sediment Budgets-- A Cautionary Note:Water Resources Research, v. 27, no. 9, p. 2483-2486. Love, D.W., 1997, Implications for models of arroyo entrenchment and distribution of archaeological sites in the middle Rio Puerco: In Duran, M.S. and Kirkpatrick, D.T., eds., Layers of Time, the Archaeological Society of New Mexico, v. 23, p. 69-84. Marcus, W.A., Nielson, C.C., and Cornwell, J.C., 1993, Sediment budget-based estimates of trace metal inputs to a Chesapeake estuary: Environmental Geology, v. 22, p. 1-9. Milliman, J.D. and Meade, R.H. 1983 World-Wide Delivery of River Sediment to the Oceans Journal of Geology, v. 91, no. 1, p. 1-21 Nordin, C.F., and Curtis, W.F., 1962, Formation and deposition of clay balls, Rio Puerco, New Mexico: U.S. Geological Survey Professional Paper 450-B, art. 28, p. 37-40. Nordin, C.F., 1963, A preliminary study of sediment transport parameters Rio Puerco near Bernardo, New Mexico: U.S. Geological Survey Professional Paper 462-C, p. C1-C21. Porterfield, G., 1972, Computation of fluvial-sediment discharge: Geological Survey Techniques of Water-Resources Investigations of the United States Geological Survey: Book 3, Chapter C3, 66 pp. Roberts, R.G., Church, M., 1986, The sediment budget in severely disturbed watersheds, Queen Charlotte Ranges, British Columbia: Canadian Journal Of Forestry Research, v. 16, p. 1092-1106. Simons, D.B., Li, R., Li, L., and Ballantine, M.J., 1981, Erosion and sedimentation analysis of the Rio Puerco and Rio Salado Watersheds: Simons Li and Associates, Report submitted to the U.S. Army Corps of Engineers, Albuquerque District, 66 p. Soil Conservation Service, 1977, The small watershed program in New Mexico, 18 p> Sutherland. R.A. and Bryan, R.B., 1991, Sediment budgeting—A case study in the Katiorin drainage basin, Kenya: Earth Surface Processes and Landforms, v. 16, p. 383-398. Trimble, S.W., 1983, A sediment budget for Coon Creek Basin in the Driftless Area, Wisconsin,1853-1977: American Journal of Science, v. 283, p. 454-474.
Table 1. Summary of sediment and runoff characteristics for USGS gaging stations in the Rio Puerco Basin.
* Based on a water year, from October 1 of the previous year to September 30 of the current year.
U.S. Department of the Interior |