From the Proceedings of the 1977 Meetings of the Arizona Section - American Water Resources Assn. and the Hydrology Section - Arizona Academy of Science - April 15-16, 1977, Las Vegas, Nevada / A 3-year study was conducted using tilted, vertical, directional, and recording rain gages (52 in all) to evaluate rainfall distribution on the Three Bar experimental watersheds in central Arizona. The tilted gages did not improve the determination of mean areal precipitation on the small watersheds because about as many tilted gages caught less rain as caught more. Although rugged and steep, the local topography exerted only minor effects on rainfall distribution compared to the major influence exerted by the Mazatzal Mountains to the windward (southwest). Forty-nine percent of wind travel was from the southwest quarter and wind averaged 4.4 mph when rain was actually falling. Wind exceeded 10 mph 9 percent of the time and 15 mph 0.4 percent of the time. Mean annual precipitation on the 600-acre study area ranged from 30 inches at 5,000 feet elevation to 22 inches at 3,400 feet (5 inches per 1,000 feet). Results of this study indicate that precipitation averages about 36 inches at 6,200 feet elevation along the Mazatzal crest near Four Peaks, about 6 inches more than published data show for the site.

From the Proceedings of the 1977 Meetings of the Arizona Section - American Water Resources Assn. and the Hydrology Section - Arizona Academy of Science - April 15-16, 1977, Las Vegas, Nevada

From the Proceedings of the 1977 Meetings of the Arizona Section - American Water Resources Assn. and the Hydrology Section - Arizona Academy of Science - April 15-16, 1977, Las Vegas, Nevada / Ratios of oxygen-18 to oxygen-16 in cellulose of dated rings from trees grown in nature and from plants grown in controlled environments have significance for retrieving information about the environment in which they grew. Phaseolus vulgaris was grown under varying conditions of controlled temperature, humidity and ¹⁸O/ ¹⁶O of irrigation water. The ¹⁸O/ ¹⁶O in plant tissue responds mostly to different environmental relative humidity; plant tissue grown under conditions of low relative humidity produce tissue relatively high in oxygen-18. Reasons for this response are not clear to us, but the relationship may prove a useful complement to established dendroclimatologic techniques.

Complete issue of the Proceedings of the 1977 Meetings of the Arizona Section - American Water Resources Assn. and the Hydrology Section - Arizona Academy of Science - April 15-16, 1977, Las Vegas, Nevada

From the Proceedings of the 1978 Meetings of the Arizona Section - American Water Resources Assn. and the Hydrology Section - Arizona Academy of Science - April 14-15, 1978, Flagstaff, Arizona

From the Proceedings of the 1979 Meetings of the Arizona Section - American Water Resources Assn. and the Hydrology Section - Arizona - Nevada Academy of Science - April 13,1979, Tempe, Arizona / Low rainfall and humidity, and high evapotranspiration, make irrigation necessary for domestic plant growth in the American Southwest. Irrigation supplies are limited. A large percentage of potable water used in Southwestern homes is used for home irrigation. Another large percentage Is returned to sewers. Water and sewer fees are increasing because of rapid urban expansion and increased water-quality standards. As fees increase, supplemental home irrigation sources become attractive and are sought. Major supplemental water sources are grey water, harvested runoff, and roof runoff. The amount of grey water depends on family size and habits. The amount of harvested runoff depends on land size and slope, soil's and material's properties, and rainfall. The amount of roof runoff depends on roof size and geometry, and rainfall. The quality of these sources is generally suitable for home irrigation. Engineering systems are required to use supplemental home irrigation water. The most preferred systems will have low capital expenditure and low energy requirements. A large and significant reduction in municipal costs and services is possible if supplemental home irrigation water is developed. Small-scale analysis indicates that costs are favorable for supplemental irrigation systems. A suggested research program emphasizes field trials and demonstrations which test design, operation, maintenance, and economics, as well as public and institutional acceptance.

Complete issue of the Proceedings of the 1978 Meetings of the Arizona Section - American Water Resources Assn. and the Hydrology Section - Arizona Academy of Science - April 14-15, 1978, Flagstaff, Arizona

From the Proceedings of the 1979 Meetings of the Arizona Section - American Water Resources Assn. and the Hydrology Section - Arizona - Nevada Academy of Science - April 13,1979, Tempe, Arizona

From the Proceedings of the 1979 Meetings of the Arizona Section - American Water Resources Assn. and the Hydrology Section - Arizona - Nevada Academy of Science - April 13,1979, Tempe, Arizona

From the Proceedings of the 1979 Meetings of the Arizona Section - American Water Resources Assn. and the Hydrology Section - Arizona - Nevada Academy of Science - April 13,1979, Tempe, Arizona / A method for estimating regional flood frequency was prepared by R. H. Roeske of the U.S. Geological Survey (USGS) in 1978 for the Arizona Department of Transportation. Hydrologists may wish to use these regression equations for estimating flood peaks or for other purposes in development or flood control engineering. Many of those needs are for watersheds smaller than 10 sq. mi., however, for which USGS measurements are scarce. Records from two groups of small experimental watersheds near Tombstone and Flagstaff, one gaged by the U.S. Department of Agriculture's (USDA) Science and Education Administration and the other by the Forest Service, were used to independently evaluate the generalized Arizona relationships in specific applications to small watershed work. The new design floods for each experimental watershed were compared with estimates made using the USGS equation for two of the six flood frequency regions (FFR) in Arizona. The study showed that use of the generalized regional curve may underestimate flood peaks. Deviations from the curve can be caused by land use changes, differences in analytical methods, and use of short records.