An investigation of salt build -up in two saline discharge lakes was conducted during 1979 in Puerto Peñasco, Mexico. Salt water was discharged to the smaller, deeper Lake I from a shrimp aquaculture prototype at an average rate of 70 liters per second. Water flowed to Lake II through a short channel, and exited the system through either evaporation or infiltration into the underlying sandy soil. In an attempt to differentiate between the evaporation and infiltration terms in the water budget, salt-budget equations have been derived for the two-lake system. These equations have been approximated in a series of monthly time steps, using averages of weekly salinity and water level measurements. Due to imprecision in the data, meaningful results have been obtained only for Lake II. The average calculated infiltration rate is 0.015 meters per day, and calculated evaporation rates show good correspondence with pan evaporation records for a station 2 kilometers away from the lakes. Examination of the salt budget equations shows that, under steady-state conditions, the ultimate salinity is finite. Thus, the maximum expected salinity of a lake may be calculated from worst-case (summertime) values of lake volume, inflow, evaporation, and salinity of incoming water.

In an effort to utilize the lithologic information contained within the thousands of drillers' logs on file with the Arizona Department of Water Resources (DWR), a computer program was developed to analyze the logs for basic aquifer characteristics. These characteristics, estimations of specific yield, hydraulic conductivity and transmissivity, are calculated for each well log by comparing drillers' descriptions of alluvial sediments to standardized drillers' terms for which predetermined specific yield values have been assigned. These values approximate conditions in alluvial basins in Arizona. This information and identified hydrostratigraphic units are then coded for computer input. The computer program then calculates estimated aquifer characteristics for the total depth of the saturated sediments and hydrostratigraphic units. When a sufficient density of acceptable drillers' logs exist in the area being studied, the logs are used to approximate the extent and depth of the hydrostratigraphic units present. Thus the gross morphology of features, such as large clay bodies, which can have a significant effect on a hydrologic system, can be evaluated. This program has proven to be valuable by providing a preliminary overview of the geohydrologic systems of alluvial basins and for calculating initial estimates of aquifer characteristics for use in DWR computer modeling studies.

A vegetable wax (candelilla), alone or in combination with petroleum waxes, was evaluated for treating soils for water harvesting. Samples were alternately weathered in a freeze -thaw cycle chamber, tested for water repellency and structural stability against water erosion, then subjected to more weathering, etc., until sample failure occurred. Soils treated with candelilla/paraffin wax mixtures were much more resistant to laboratory freeze -thaw cycle weathering than those soils treated with either of the waxes alone. Weatherability was further improved, and wax requirement reduced by (1) prior stabilization of the soil with cellulose xanthate made from chemically pulped waste paper; (2) incorporating 28 of a commercial antistripping agent into the wax; and (3) substituting a residual type petroleum wax for the paraffin in the wax mixtures.