Civil Engineering ETDs

Publication Date

5-20-1970

Abstract

The San Pedro Creek basin has a drainage area of 195 square miles stretching from the eastern slopes of the Sandia Mountains to the Rio Grande in the northwest. The lower elevations in the basin have a typical semiarid climate, but the higher elevations are more humid. The basin is disected by dendritic patterned drainage systems; approximately twenty-two of these systems compose the basin. The area is a woodland with juniper, pinon, and grasses prevalent. The geology of the area is very complex numerous faults occur within the basin, and three major faults border it. The soils in the basin, ranging from deep to shallow, are eroding at moderate to high rates.

Precipitation in the form of thunderstorms is the initial source of water; the amount and distribution varies considerably. The amount increases with altitude at a rate of 3.5 inches per 1000 feet. Partial duration and annual flood series frequency curves were drawn from crest-stage gage data for a part of the basin.

Five hydrographs derived from a unit hydrograph, individual sub-basins, two storm transpositions, and Snyder's Method for synthetic hydrographs were computed for the watershed and compared. Only two were found to be representative of the watershed for a given frequency. The standards used were developed in a ten-year study by the U. S. Geological Survey on a nearby watershed. Volumes and peak discharges of the five hydrographs and using various other equations and graphs were also compared but no relation was available. As a result, flood volume rather than peak discharge was found to be more descriptive of the basin and its hydrology.

Sedimentation was found to be dependent on the flood volume and not the peak. Bedload samples from the mouth of the stream were tested for size distribution. 30 percent was coarser than 1 mm, and the median diameter was 0.5 mm. Bedload was computed using the Kalinske Equation, the Schoklitsch Equation, and a graphical solution of this modified Einstein procedure. The resulting volumes did not compare favorably with each other; the modified Einstein procedure gave values which fell between values from the other two methods.

Total sediment load was computed using the Straub Equation and a rate of sediment production computed by the U.S. Bureau of Reclamation for tributary inflow into the Rio Grande from this area. These results do not compare favorably either.

Suspended sediment was not computed because no data had been collected in this basin. It was concluded that current methods of computing runoff and sediment in the semiarid areas are inadequate, and at best, are approximations. Raw data on volumes of flow for a known frequency and its respective sediment concentration are necessary in the study of the San Pedro Creek basin.

Document Type

Thesis

Language

English

Degree Name

Civil Engineering

Level of Degree

Masters

Department Name

Civil Engineering

First Committee Member (Chair)

Jose Eleazar Martinez

Second Committee Member

John Bryan Carney Jr.

Third Committee Member

Marvin Clark May

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