Conselho Nacional de Desenvolvimento Científico e Tecnológico / The creation of rural settlements in areas of agrarian reform has been allowing greater social inclusion for families who were previously deprived of land ownership and subsequent income source. However, unorganized splitting or inadequate location of infrastructure in places historically worked can hamper economic and social activities of a settlement project, apart from causing environmental damage. This study had the following aims: (a) temporal diagnosis of land use and occupation of the Alvorada settlement in two distinct periods, before its creation and after 12 years of occupation, (b) to map the land-use conflicts in areas of permanent preservation in two small watersheds located in the settlement, (c) to analyze the existing relationship between land use, riparian zones and water quality of streams in the two small watersheds, and (d) to assess the potential of water used for human consumption in rural properties as a risk factor to consumers health. The Alvorada settlement is situated in southern part of the city of Júlio de Castilhos, located in the central region of Rio Grande do Sul. To better discuss the results, this dissertation is organized in three studies. In the first, the temporal diagnosis of use and occupation of the land in the Alvorada settlement by means of cartographic products in two distinct periods, before its creation and after 12 years of settlement, was made, and the conflicts of land use in area of preservation in two small watersheds were identified. The second study dealt with the relations between water quality, land use and riparian zone in two small watersheds. In the third study monitoring the water quality of sources used for drinking-related to land use and conditions surrounding the protection of the cavity drilled in two small watersheds was performed. Analysis of thematic maps allowed better visualization of changes in the geographic area of the settlement. The main changes relate to population pressure and the replacement of areas formerly used for pasture or native grassland by annual crops and extensive dairy farming. Both the small watersheds showed land use conflicts in the areas of permanent preservation totaling 86.39% of the area in a small watershed and 100% in two small watershed. The waters of the streams showed a low concentration of chemical elements reflecting the low use of agricultural factors by the farmers. The organic load showed a small contamination, this is due to physical degradation of the landscape. There was no improvement in water quality parameters in the small watershed with the highest percentage of riparian forests which was attributed to the loss of their original characteristics by grazing animals and the felling of trees inside the forest. The water used for drinking water in the two small basins showed physiochemical and microbiological parameters outside limits for drinking water as established by the Ministry of Health; thus representing a high risk and health damage to humans who drink it. / A criação de assentamentos rurais em áreas de reforma agrária tem promovido maior inserção social para famílias que anteriormente estavam desprovidas da propriedade da terra e de fontes de renda. Entretanto, o parcelamento desordenado ou locação inadequada da infra-estrutura em locais historicamente explorados pode inviabilizar as atividades econômicas e sociais de um projeto de assentamento, além de causar danos ambientais. Este trabalho teve como objetivos: (a) Diagnóstico temporal do uso e ocupação da terra no assentamento Alvorada em dois períodos distintos, anterior a sua implantação e 12 anos após; (b) Mapear os conflitos de uso da terra em áreas de preservação permanente em duas pequenas bacias hidrográficas localizadas no mesmo assentamento; (c) Analisar as relações existentes entre uso terra, zona ripária e qualidade da água de arroios em duas pequenas bacias hidrográficas; (d) Avaliar o potencial da água utilizada para consumo humano nas propriedades rurais como fator de risco à saúde dos consumidores. O assentamento Alvorada situa-se na porção Sul do município de Júlio de Castilhos, região central do Estado do Rio Grande do Sul. Para melhor discussão dos resultados, a dissertação foi organizada em três estudos: No primeiro deles fez-se o diagnóstico temporal do uso e ocupação da terra no assentamento Alvorada através de produtos cartográficos de dois períodos distintos, anterior a sua implantação e 12 anos após e, identificaram-se os conflitos de uso da terra em área de preservação permanente em duas pequenas bacias hidrográficas. O segundo estudo tratou das relações entre qualidade da água, uso da terra e zona ripária em duas pequenas bacias hidrográficas. No terceiro estudo fez-se um monitoramento da qualidade da água de fontes utilizadas para consumo humano relacionando-a ao uso da terra no entorno e condições de proteção da cavidade perfurada nas duas pequenas bacias hidrográficas. A análise dos mapas temáticos possibilitou melhor visualização das alterações ocorridas no espaço geográfico do assentamento. As principais alterações referem-se à pressão demográfica e a substituição de áreas anteriormente utilizadas com pastagens ou campo nativo por cultura anual e pecuária leiteira extensiva. Nas pequenas bacias hidrográficas, ambas apresentaram conflitos de uso da terra em área de preservação permanente sendo 86,39 % da área na pequena bacia hidrográfica 1 e 100 % na pequena bacia hidrográfica 2. As águas dos arroios apresentaram baixa concentração de elementos químicos refletindo a baixa utilização de insumos agrícolas pelos agricultores. A carga orgânica indicou uma pequena contaminação, isso se deve a degradação física da paisagem. Não houve melhoria nos parâmetros de qualidade da água na pequena bacia hidrográfica com maior percentual de matas ripárias, o que foi atribuído a descaracterização delas pelo pastoreio animal e derrubada das árvores no interior da mata. As águas utilizadas para consumo humano nas duas pequenas bacias apresentaram parâmetros físicoquímicos e microbiológicos fora dos padrões de potabilidade estabelecidos pelo Ministério da Saúde, este fato representa alto risco e agravos à saúde dos seres que a consomem.

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 / Hydrologic information is needed to understand and control water pollution from semiarid rangelands. However, the hydrologic systems under any given conditions must be understood and the effects of various land uses predicted. Based on the concept of partial area response, a runoff tracer study was conducted on two small watersheds. The watersheds were partitioned into four geomorphic subzones or hydrologic response units. Each of the four zones on both watersheds was treated with about 1 kg/ha of an individual water soluble herbicide. Runoff volumes and sources estimated using the tracers were consistent with results from simulation studies. Also, the principle of corresponding runoff and pollutant discharge rates was used to develop two methods of runoff hydrograph estimation from each of the geomorphic subzones. Method 1 matched the mean total concentration and total runoff volume. Method 2 matched the instantaneous total concentration and the instantaneous runoff rate from the entire watershed. Results from the two methods suggested that, although they may be equivalent with respect to runoff volume, Method 2 may be more consistent with respect to peak discharge.

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 / Two native grass species, blue grama and sidecoats, were successfully seeded on a semiarid rangeland on the walnut gulch experimental watershed in southeastern Arizona. Optimum seeding dates selected were those within the time period most likely to receive precipitation, and grass stands were established in two successive years with average rainfall. Shrubs were killed by root-plowing at a depth of 14 inches, a procedure which was more than 95% successful in controlling sprouting shrubs. Forage production measurements taken on nm-28 sideoats and Vaughn sideoats showed a yield of 1,950 and 2,643 pounds of forage per acre, respectively, for the 2 years following the seeding, whereas untreated sites produced 23 and 25 pounds per acre of forage. Results indicate that success in establishing a stand of native grass is increased through use of existing hydrologic data.

From the Proceedings of the 1973 Meetings of the Arizona Section - American Water Resources Assn. and the Hydrology Section - Arizona Academy of Science - May 4-5, 1973, Tucson, Arizona / Five livestock watering ponds on the walnut gulch experimental watershed were instrumented to evaluate the use of these ponds as a method for comparing rainfall amounts with runoff sediment volumes. Pond drainage area, vegetative cover, soil type, percent slope, and years of record were tested. Instrumentation consisted of water level recorders, and a topographic survey of each stock pond to ascertain its storage capacity. The results to date have been insufficient to reach definite conclusions due to instrumentation and surveying problems, and because of the natural variability of thunderstorm rainfall. Since most of these problems have now been corrected, future data should yield valuable hydrologic data for semiarid rangelands by means of these instrumented stock ponds.

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 / Tumamoc Hill, an 869-acre (352 ha) desert area near Tucson, Arizona, is being considered as a controlled- access environmental site. Water affects the site's geology, soils, vegetation, wildlife, and archaeology. The Hill is drained by three small watersheds. The largest is rapidly urbanizing upstream. Hydrologic aspects include potential flooding and erosion hazards. These may be reduced simply, economically, and wisely in a land-use plan. Upstream development increases storm runoff volumes, and flood peaks, and frequencies routed through the site, and threatens existing downstream urban development. Return periods of channel-overflow floods become shorter with urbanization. The region may be managed to reduce hydrologic hazards by three procedures: widen channels, install low checkdams, and vegetate drainageways. These methods will slow down runoff velocities, and increase cross -sectional area of flow and roughness coefficient. More water would also be available for vegetation and wildlife. The land-use plan should include environmental education programs. These would present important effects of water on the natural ecology, and hydrologic aspects of watershed urbanization.

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 erosion prediction method that has recently received wide attention in the United States is the universal soil loss equation which is given as: a=rklscp. Where a = estimated soil loss (tons/acre/year), r = a rainfall factor, k = a soil erodibility factor, l = a slope length factor, s = a slope gradient factor, c = a cropping-management factor, and p = an erosion control practice factor. Data collected on the walnut gulch experimental watershed in southeastern Arizona were used to estimate these factors for semiarid rangeland conditions. The equation was then tested with data from watersheds of 108 and 372 acres. The predicted value of annual sediment yield was 1.29 tons/acre/year as compared with an average 1.64 tons/acre/year for 4 years of data for the 108-acre watershed, and a sediment yield of 0.39 tons/acre/year was predicted for the 372-acre watershed as compared with the measured value of 0.52 tons/acre/year. Although good agreement was noted between predicted and actual sediment yield, additional work is needed before the equation can be applied to other areas of the southwest.

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 stochastic model is presented for the prediction of sediment yield in a semi-arid watershed based on rainfall data and watershed characteristics. Random variables which lead to uncertainty in the model are rainfall amount, storm duration, runoff, and peak flow. Soil conservation service formulas are used to compute the runoff and peak flow components of the universal soil loss equation, and a transformation of random variables is used to obtain the distribution function of sediment yield from the joint distribution of rainfall amount and storm duration. Applications of the model are in the planning of reservoirs and dams where the effective lifetime of the facility may be evaluated in terms of storage capacity as well as the effects of land management of the watershed. In order to calibrate the model and to evaluate the uncertainties involved, experimental data from the Atterbury watershed near Tucson, Arizona were used.