From the Proceedings of the 1990 Meetings of the Arizona Section - American Water Resources Association and the Hydrology Section - Arizona-Nevada Academy of Science - April 21, 1990, Arizona State University, Tempe, Arizona / Effects of applications of cytokinin-like and gibberellic growth regulators, nitrogen fertilizer, and irrigation on the development of containerized eldarica pine (Pinus brutia var. eldarica) seedlings was studied in a greenhouse for 13 weeks. All concentrations of growth regulators reduced nitrogen content of needles and dry weight of shoots; importantly, medium and high concentrations also adversely affected root collar diameter growth and shoot elongation. Nitrogen fertilization alone was not significant in its effect on seedling development, due probably to the nitrogen-rich nature of the potting medium. It is suggested that contentration is a critical factor when applying growth regulators, as phytotoxicity of seedlings can result at high rates.

From the Proceedings of the 1991 Meetings of the Arizona Section - American Water Resources Association and the Hydrology Section - Arizona-Nevada Academy of Science - April 20, 1991, Northern Arizona University, Flagstaff, Arizona / The erosion process by overland flow was analyzed in its fundamental aspects. A general predictive erosion equation was developed by combining the conditions for conservation of mass of the sediment, boundary hydraulic shear, and the sediment transport formula of Einstein-Brown. The ability of the equation to predict sediment yield from overland flow areas was demonstrated using field data from rainfall simulator plots. Comparison of the results indicated that the erosion equation presented herein can be used to predict sediment yield from unrilled overland flow areas with satisfactory confidence.

From the Proceedings of the 1991 Meetings of the Arizona Section - American Water Resources Association and the Hydrology Section - Arizona-Nevada Academy of Science - April 20, 1991, Northern Arizona University, Flagstaff, Arizona / New technical approaches and cost cutting alternatives are being utilized in the environmental engineering field. These unique methods are used in the mapping, delineation and remediation of contaminated sites. One development which has seen a sudden increase in the recent past is the utilization of soil vapor surveys to map contamination plumes in the vadose zone. Using the soil vapor method, industrial sites and sites containing potential buried drums or underground storage tanks can be quickly evaluated for the presence of volatile contaminants. This information can be especially important in property transactions where buyers desire to protect themselves from potential costly clean-ups. The soil vapor survey consists of sampling volatile vapors in the vadose zone and analysis of the vapors on analytical instruments. The survey targets those contaminants which have volatilized from residues in soils or shallow ground water. One method of sampling soil vapors is penetrating five to ten feet into the sub-surface with a sampling probe. Upon collection of the vapors, concentrations may be measured. The analytical instruments can range from simple Drager Tubes to a laboratory gas chromatograph. The methodology for selecting sampling locations depends on the site. An underground storage tank facility may be approached by completing sampling locations at the tank pit and near the product lines. A grid sampling location map may be used to sample a property with an unknown organic content. Soil vapor surveys have limitations in regards to soil types, sampling depths and constituents being analyzed. However, given the proper conditions, soil vapor surveys can provide qualitative data at lower costs than alternative methods.

From the Proceedings of the 1989 Meetings of the Arizona Section - American Water Resources Association and the Hydrology Section - Arizona-Nevada Academy of Science - April 15, 1989, University of Nevada, Las Vegas, Nevada

From the Proceedings of the 1989 Meetings of the Arizona Section - American Water Resources Association and the Hydrology Section - Arizona-Nevada Academy of Science - April 15, 1989, University of Nevada, Las Vegas, Nevada

From the Proceedings of the 1989 Meetings of the Arizona Section - American Water Resources Association and the Hydrology Section - Arizona-Nevada Academy of Science - April 15, 1989, University of Nevada, Las Vegas, Nevada / Casa del Agua is a research and demonstration project to test the efficiency and liveability of a house that has been relandscaped and redesigned with water saving and recycling devices. Ongoing research focuses on six interrelated tasks: 1) water quality and sampling to characterize graywater and rainwater and to determine their potential to impact the environment; 2) water balance analysis that quantifies fresh water use, graywater production and use, and rooftop runoff and use; 3) evaluation of system components that could enhance graywater reuse; and 4) maintenance and modification of existing systems. An interpretation of recent data and information derived from the performance of the above tasks indicates the effectiveness of the project's water-saving strategies, as well as other significant findings relevant to water conservation in an urban, residential setting.

From the Proceedings of the 1989 Meetings of the Arizona Section - American Water Resources Association and the Hydrology Section - Arizona-Nevada Academy of Science - April 15, 1989, University of Nevada, Las Vegas, Nevada / A typical single family residence in Tucson, Arizona (Casa del Agua) was retrofitted with water conserving devices, graywater and rainwater recycling systems, and a low water use landscape. An educational tour designed to promote the incorporation of these water saving techniques has been ongoing at the home since December, 1985. A questionnaire survey was administered between April and July 1988 to determine the extent of water conservation behavior, demonstrated by the adoption of the water conservation techniques, of the Pima County population and the tour participants. Both population samples exhibited similar water conservation behaviors. It was also determined, from the analysis of the survey results, that the tour led to additional water conservation technique adoption.

From the Proceedings of the 1990 Meetings of the Arizona Section - American Water Resources Association and the Hydrology Section - Arizona-Nevada Academy of Science - April 21, 1990, Arizona State University, Tempe, Arizona / A test protocol was evaluated for estimating the acute toxicity of urban stormwater runoff to aquatic life. Potential deleterious effects of storm flows on the aquatic community of small artificial impoundments were examined by application of short-term bioassays. Definitive, static renewal, acute toxicity tests were performed using the fathead minnow, Pimephales promelas, and the crustacean, Daphnia magna. The feasibility study indicated that short-term bioassays may provide an alternative to individual chemical constituent measurements and comparisons to numerical water quality criteria for protection of aquatic life. Biotoxicity tests may identify synergistic interactions to chemicals which individually meet specific water quality criteria but collectively lead to toxicity.

From the Proceedings of the 1990 Meetings of the Arizona Section - American Water Resources Association and the Hydrology Section - Arizona-Nevada Academy of Science - April 21, 1990, Arizona State University, Tempe, Arizona / A study of over 11,000 event rainfall and associated direct runoff events from 100 small watersheds was done, in a search for distinct patterns of runoff response and/or association with land type. The results show unexpected variety in the geometry and scale of the rainfall -runoff response. Groupings of similar response type and magnitude were made, and the associations with vegetative cover were tested. Five separate response groups were identified as follows: 1) Inactive, characterized by no recorded responses to any rainstorm in an extended period of record; 2) Complacent, characterized by a very small part of the rainfall (ca 0.1 to 3 percent) being converted to direct runoff, often as a linear response; 3) Standard behavior, the expected "textbook" response common to agricultural lands and humid sites, and in which the runoff slope increases with increasing rainfall, and the scale of runoff far exceeds the complacent response; 4) Violent behavior, in which an abstraction threshold of 2 -6 cm clearly precedes a sudden high response; and 5) Abrupt response in which a very high portion of the rainfall is converted to event runoff without appreciable abstraction, as typified by extensively urbanized drainages. The responses and the group identifications were parameterized by a simple broken -line linear rainfall-runoff equation, and a dichotomous key based on coefficient values is proposed. Only mild associations between response type or coefficient values and the four vegetative covers (Forest, Range, Agriculture, and Urban) were found. The variety of hydrologic behavior on forested watersheds encompassed that of the other three land types.

From the Proceedings of the 1990 Meetings of the Arizona Section - American Water Resources Association and the Hydrology Section - Arizona-Nevada Academy of Science - April 21, 1990, Arizona State University, Tempe, Arizona / Although riparian system researchers intuitively understand the general role of flooding in these plant communities, very little quantitative analysis or physical modelling of these flooding effects has been undertaken. This paper describes a methodology for analyzing flood influences by utilizing vegetation monitoring along river transects and a sophisticated flood hydraulics computer model (HEC 2). The project is addressing important questions such as "What magnitude of foods will alter the physical structure and species composition of the plant community? Are major floods essential in creating open floodplain areas wherein regeneration of riparian plants can take place? How does flood timing during the growing season affect the germination of seeds and survival of seedlings?" The flood hydraulics study described herein provides an analysis method that is readily transferrable to other riparian systems, and anticipated results may offer some quantification of flooding characteristics which translate to any system composed of similar plant species. For instance. if mortality thresholds of such physical forces as flow velocity. depth. tractive shear stress, and stream power can be identified for selected riparian species, such information may be quite valuable to those engaged in restoration of disturbed systems. in specifying reservoir releases needed to maintain riparian vegetation downstream of dams, and in instream flow protection efforts seeking to protect essential environmental processes which sustain natural riparian systems.