From abstract: This report presents the theory and method of calculation used by MIX2, describes the input to the program, presents results of two test cases, and provides a program listing.

The Anza-Terwilliger area consists of about 96 square miles (24-9 square kilometers) in the upper parts of the Santa Margarita River and Coyote Creek drainage basins in Riverside County, Calif., about 90 miles (145 kilometers) southeast of Los Angeles. This report deals with geology, steady state and transient state of ground water, net depletion of ground water, surface-water flow, precipitation, chemistry of water, land and water use, and gravity data for the Anza-Terwilliger area. The data indicate that the rate of ground-water depletion ha's accelerated since 1950. Pumping depressions adjacent to the Cahuilla Indian Reservation have increased the hydraulic gradient and are.causing water beneath the reservation to flow toward these depressions. Total depletion of ground water since 1950 is about 14,000 acre-feet (17.3 cubic hectometers). Chemical analyses indicate that the ground water in local areas contains concentrations of nitrate above that recommended by the Environmental Protection Agency for human consumption.

From introduction: The primary objective of this study was to determine the net transport of zinc into the study area from urbanized perimeter, out of the study area across the northern boundary of the study area, and across the sediment-water interface within the study area, all within a limited time period. A secondary objective was to assemble as much data on other trace metals--their concentrations and chemical states in water, suspended solids, sediments and interstitial fluids--as possible within the time and funding constraints of the study in order to describe the existing trace metal conditions in the south bay. Thus the bulk of effort was directed toward evaluating the distribution and movements of zinc, but the data collected on the distribution and movements of zinc, but the data collected on the distribution of other metals is important and is reported here.