From the Proceedings of the 1974 Meetings of the Arizona Section - American Water Resources Assn. and the Hydrology Section - Arizona Academy of Science - April 19-20, 1974, Flagstaff, Arizona / A plan for the reuse of sewage effluent is proposed for the city of Tucson, Arizona. Several kinds of use would be possible, but utilization for irrigation of existing farmland in the Avra-Marana area seems particularly attractive for several reasons: (1) conveyance can be accomplished by gravity flow, (2) no tertiary treatment is required for the presently grown crops, (3) the nutrients in the effluent would be better used, and (4) effluent use would reduce the pumpage of high quality groundwater, conserving it for municipal or other uses. An exchange of wastewater for groundwater for use in the city system is seen as a good alternative to the present practice of the city purchasing farmland in Avra valley in order to acquire the groundwater for conveyance to the Tucson basin. Objectives to maximize the quantity and efficiency of wastewater use may not appear compatible with the profit maximization motive of the individual farmer, and suitable provisions will have to be written into wastewater sales agreements to assure coordination between user and supplier.

From the Proceedings of the 1974 Meetings of the Arizona Section - American Water Resources Assn. and the Hydrology Section - Arizona Academy of Science - April 19-20, 1974, Flagstaff, Arizona / In the lower reaches of the Colorado River, damages from the increase in salinity to U.S. water users are now estimated to be about 53 million dollars per year and will increase to about 124 million dollars per year by the year 2000 if no salinity control measures are taken. Physical, legal, economic, and institutional aspects of the salinity problem and proposed actions to mesh salinity control with a total water management plan for the basin are discussed. A scheme is presented for planning under the Colorado River water quality improvement program. Recent legislative action is also discussed which provides control plans to improve the water quality delivered to Mexico as well as upper basin water users. These efforts now under study will assure the continued, full utility of Colorado River water to U.S. users and Mexico. However, more extensive development of the basin's natural resources puts new emphasis on total resources management through improved water and land use planning to conserve a most precious western resource - water.

From the Proceedings of the 1974 Meetings of the Arizona Section - American Water Resources Assn. and the Hydrology Section - Arizona Academy of Science - April 19-20, 1974, Flagstaff, Arizona / Semiarid environments exhibit certain hydrologic characteristics which must be taken into consideration for the effective modeling of the behavior of catchments in these areas. Convective storms, which cause most of the runoff, occur in high intensity and short duration during the summer months and are highly localized so that only a small portion of the catchment actually contributes flow to the storm hydrograph. Also, streams in semiarid catchments are ephemeral with flow occurring only about 1 percent of the time. This study attempts to develop a simple synthetic catchment model that reflects these features of the semiarid environment and for which (1) the simplifying assumptions do not preclude the inclusion of the important components of the runoff process, and (2) parameters of the equations representing the component processes have physical interpretation and are obtainable from basin characteristics so that the model may be applicable to ungaged sites. A reductionist approach is then applied in which the entire catchment is subdivided into a finite number of meshes and the various components of the runoff phenomenon are delineated within each mesh as independent functions of the catchment. Simplified forms of the hydrodynamic equations of flow are used to route flow generated from each mesh to obtain a complete hydrograph at the outlet point.

From the Proceedings of the 1974 Meetings of the Arizona Section - American Water Resources Assn. and the Hydrology Section - Arizona Academy of Science - April 19-20, 1974, Flagstaff, Arizona / The inner basin is a collapse and erosional feature in San Francisco Mountain, an extinct volcano of late Cenozoic age, which lies approximately eight miles north of flagstaff, Arizona. The main aquifer's coefficient of transmissibility is approximately 14,000 gallons per day per foot and the storage coefficient was 0.08. Aquifer boundaries increased rates of drawdown of water levels in the inner basin well field. Inner basin springs which issue from perched reservoirs are not affected by pumpage of inner basin wells. Recharge is greater than the average yield from springs and wells in the basin which has an average of 8,000 acre-feet of water in storage in the principal aquifer. A large amount of water is lost from the inner basin aquifer system via leakage into underlying fractured volcanic rocks. It is believed that a part of this water could be intercepted by pumpage from a well constructed in the interior valley.

From the Proceedings of the 1974 Meetings of the Arizona Section - American Water Resources Assn. and the Hydrology Section - Arizona Academy of Science - April 19-20, 1974, Flagstaff, Arizona / The Coconino Sandstone of Permian age is the principal aquifer for the Woody Mountain well field, a source of municipal water for the City of Flagstaff. Wells of highest yield are located where the frequency of occurrence of faults is greatest and where the principal aquifer is down-faulted. The locations and displacements of all but the most prominent faults cannot be determined using conventional geologic mapping techniques because relatively undeformed Late Cenozoic basaltic lavas cover the faulted Paleozoic rock terrain. Approximately 3,500 feet of Paleozoic sedimentary rocks, which have little magnetic effect and which have a density of approximately 2.4, comprise most of the stratigraphic section in the well field. The basalt cover is strongly reversely magnetized and has a density of approximately 2.7. Changes in thickness of the basalt cover cause changes in the geomagnetic and gravitational field strength. Analysis of data from geomagnetic and gravity surveys was used to delineate boundaries and thicknesses of blocks of basalt which fill down -faulted areas. The correlation coefficient (r² = 0.96) for plots of known thicknesses of basalt versus complete Bouguer anomaly supports use of gravity data to estimate displacement of down -faulted blocks.

From the Proceedings of the 1974 Meetings of the Arizona Section - American Water Resources Assn. and the Hydrology Section - Arizona Academy of Science - April 19-20, 1974, Flagstaff, Arizona / An examination of potential water sources for power plant cooling in Arizona is presented along with information pertinent to Arizona's future water needs relative to electrical usage growth. It has been projected that Arizona's peak electrical power demands in 1980 and 1990 will exceed that of 1970 by some 5000 megawatts and 16000 megawatts of electricity respectively. At present, the bulk of the electrical energy generated in the western states originates at hydroelectric installations. Utilization of nuclear reactors for power generation requires a larger amount of cooling water than is required for a comparable fossil-fueled plant. It is suggested that the utilization of reclaimed wastewater for cooling purposes is a viable and attractive alternative to groundwater pumpage from both economic and ecological standpoints. Savings arise from conservation of fuel normally required for well pumps, costs of well construction are not required, quantities of fresh water should be released for consumption by alternate users, and a previously unused resource would be effectively recycled.

From the Proceedings of the 1974 Meetings of the Arizona Section - American Water Resources Assn. and the Hydrology Section - Arizona Academy of Science - April 19-20, 1974, Flagstaff, Arizona / Diatremes of Late Pliocene age in the Hopi Buttes area of Arizona are becoming increasingly important sources of groundwater to the Indian nations. These volcanic vent structures are prime sources of groundwater because sedimentary formations in the Hopi Buttes area yield only limited amounts of water or yield poor quality water. Diatremes act as traps for groundwater and some have yielded moderate amounts of good quality water to wells. Surface geologic investigations and analysis of drillers' logs indicate that structural relationships and diatreme lithology provide a means to project the hydrologic properties of the vent. Diatremes most suitable for groundwater development should have a diameter greater than one half mile, should contain volcanic tuff and breccia at its center, and should be fractured from collapse. Lava flows covering diatremes reduce recharge from sheet wash or from ephemeral stream flow. Data from geomagnetic and gravity surveys will be analyzed to determine its suitability for predicting subsurface size, shape, and lithology of the diatreme. The integration of geophysical and surface geologic data will reveal the total geometry of the structure enabling the most accurate appraisal of the hydrologic properties of the diatreme.

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 / Combined urban, agricultural, industrial and mining groundwater withdrawal from the Santa Cruz River Basin exceeds natural aquifer replenishment by 74,000 acre -feet annually. Four ameliorative water management alternatives are presented singly and in combination with one another. These alternatives are importing Colorado River water, exchanging treated effluent with mining and agricultural interests for groundwater, interbasin water transfer, and retiring farmlands for groundwater rights. These management philosophies are applicable to most economically emergent urban areas in arid and semiarid regions.

South Africa’s growing elephant populations are concentrated in relatively small enclosed protected areas resulting in the over utilisation of the available food sources. Elephants and other herbivores as well as other natural disturbances such as fires and droughts play an important role in maintaining savannah environments. When these disturbances become too concentrated in a particular area the vegetation composition may be negatively affected. Excessive damage to the vegetation would result from exceeding the capacity of a protected area to provide food resources. The effect of the 120 elephants on the vegetation of Welgevonden Private Game Reserve, is not known. The rugged terrain of this reserve makes it a difficult, time consuming and labour intensive exercise to conduct ground studies. Satellite images can be used as a monitoring tool for vegetation change and improve the quantity and quality of environmental data to be collected significantly, allowing more informed management decision-making. This study evaluated the use of satellite imagery for monitoring elephant induced vegetation change on Welgevonden Private Game Reserve. The LANDSAT Thematic Mapper multispectral images, acquired at two yearly intervals from 1993 until 2007 were used. However, no suitable images were available for the years 1997, 2001 and 2003. A series of vegetation change maps was produced and the distribution of water sources and fire occurrences mapped. The areas of change were then correlated with the spatial distribution of water points and fire occurances, with uncorrelated areas of change. This was analysed using large animal population trends, weather data and management practices. On the visual comparison of the vegetation maps, it was seen that over this time period there was some decrease and thinning of woodland, but the most notable change was the increase of open woodland and decrease in grasslands. Using only the digital change detection for the period 1993 to 2007, a general increase in vegetation cover is seen. But this generalisation is misleading, since comparing the digital change detection to the vegetation maps indicates that while vegetation cover may have increased, significant changes occurred in the vegetation types. Most of the areas of significant change that were identified showed a strong positive correlation with burnt areas. The distribution of the water sources could not be directly linked to the vegetation change although rainfall fluctuations seemed to have accelerated vegetation changes. Years with high game counts, such as 1999, also coincide with very low rainfall making it difficult to differentiate between the effects of heavy utilisation of vegetation and low rainfall. Furthermore, many of the initial vegetation changes could be the result of land use changes due to the introduction of browsers, selective grazers and elephants that allow for more natural utilisation of the vegetation. Remote sensing makes it possible to successfully track changes in vegetation and identify areas of potential elephant induced vegetation change. Vegetation changes caused by disturbances, such as fire and anthropogenic activities, can be accounted for but it is not possible to conclude with a high level of certainty that the further changes seen are solely a result of elephant damage. Further work is required to reliably isolate elephant induced vegetation changes, as well as to establish the effects these changes have on the ecosystem as a whole. / Environmental Sciences / (M. Sc. (Environmetal Sciences))

This study aims at investigating household food accessibility categories (food insecure, vulnerable, marginal and food secure) of rural households in Sekhukhune district of Limpopo province. The study is based on five wards in Mamone village in the Limpopo province of South Africa. Ten households from each ward were randomly selected for the study. Structured questionnaires administered by enumerators were used to collect information from household heads. In all 50 household heads constitutes the sample size for the study. Data was collected from 20 August 2007 to 25 August 2007. Responses in the questionnaires were tabulated, coded and processed using Statistical Package for Social Sciences (SPSS) programme. Based on comprehensive food security and vulnerability analysis the study showed that over 70 per cent of the sampled households were food insecure. Lack of education, income sources, water source, and infrastructure were some of the important factors contributing to food insecurity. The government should also give special attention to policy measures that guide towards the provision of household assets. It is recommended that special attention be given to measures that will provide the necessary factors that negatively affect household food security and vulnerability. / Agriculture, Animal Health and Human Ecology / M.A. (Human Ecology)