Thesis (M.S. - Civil Engineering and Engineering Mechanics)--University of Arizona, 1984. / Includes bibliographical references (leaves 79-81).

Thesis (M.S. - Renewable Natural Resources)--University of Arizona, 1985. / Includes bibliographical references (leaves 119-122).

Thesis (M.S. - Renewable Natural Resources)--University of Arizona. / Includes bibliographical references.

Thesis (M.S.)--Washington State University, August 2006. / Includes bibliographical references (p. 29-31).

A study was undertaken to determine the effect of urbanization on the rainfall-runoff relationship of a semiarid region. A concentrated network of rain gages was installed on the urban Tucson Arroyo-Arroyo Chico Watershed located in the city of Tucson, Arizona. Rainfall data from this watershed were compared with that of the non-urban Atterbury Experimental Watershed located to the southeast of the city of Tucson in order to determine if there were significant differences in the runoff from these two watersheds. In addition, test plots were constructed by the researcher for the study of the effects of intensity of precipitation, season, antecedent moisture, and percent of impervious cover on the rainfall-runoff relationship. Data from the test plots were compared with that of the Tucson Arroyo-Arroyo Chico Watershed. A prediction model was developed for the Tucson Arroyo-Arroyo Chico Watershed. The feasibility of retaining urban runoff for more beneficial uses was investigated. It was determined that the runoff from the urban Tucson Arroyo- Arroyo Chico Watershed was 4.75 times greater per square unit of area than that from the non-urban Atterbury Experimental Watershed. Significant factors in the rainfall-runoff relationships of the test plot data were found to be intensity of precipitation and amount of impervious cover. Season was found not to be significant. Antecedent moisture was a significant factor in the analysis of variance of the data. However, it was not significant in the regression analysis. In the comparison of the test plot data and the data from the Tucson Arroyo-Arroyo Chico Watershed, it was found that intensity of precipitation was the predominant factor in the rainfall-runoff relationship. In plotting the effects of intensity of precipitation versus runoff, the resulting graph indicated an increasing effect of impervious cover and intensity of precipitation on runoff from the test plots. A regression model was developed from the data of the Tucson Arroyo-Arroyo Chico Watershed. The factors of average precipitation and intensity of precipitation accounted for 82 percent of the variation in the analysis. Of these two factors, intensity of precipitation accounted for 68 percent of the variation. Duration of precipitation and the antecedent moisture index did not significantly increase the correlation coefficient of the regression analysis when they were included. The projected runoff from the city of Tucson would amount to less than 10 percent of the present yearly use. The treatment necessary for the domestic use of urban runoff would be greater than the present cost of producing municipal water from well-sites. Recharging this water into the groundwater supply appears to be the most feasible method of utilizing urban runoff at this time.

This study was based on the premise that watershed management on mountainous forested land generally, and in the Coast Mountains of British Columbia more specifically, will be benefitted by further knowledge of soil water drainage from the root zone of forested soils and by such development of methods of measuring soil water drainage as will make increased sampling more feasible. The study was concerned with (1) the development and application of two methods for evaluating soil water drainage; a tension lysimeter system and a method based on Darcy's equation, (2) the exploration of the relationship between rainfall, soil water drainage and streamflow. It was carried out at a forest site of Jamieson Creek Experimental Watershed in the upper Seymour River basin, southwestern B.C. near Vancouver. The tension lysimeter system incorporated a simple capability for manually regulating suction on the lysimeter plate in close conformity with the tension in surrounding soil and also a lysimeter plate that ensured satisfactory hydraulic contact between it and the soil. The application of Darcy's equation for calculating soil water drainage was based on field determinations of both soil hydraulic conductivity and hydraulic gradient at the study site. Soil water drainage rates measured by the tension lysimeter system and those calculated by Darcy's equation showed good agreement, although the former were consistently and slightly higher. It was concluded that each method can provide reasonable estimates of soil water drainage and may be particularly useful in developing countries where a cheap labor source permits extensive and frequent soil water drainage sampling within a watershed. Soil water drainage amounts obtained by these two methods during each of two drying periods were in good agreement with those estimated from a water balance equation. Possible sources of error associated with soil water drainage measurements by tension lysimeter and by the method of Darcy's equation are discussed and possible improvements suggested. This study also indicated that, in the humid coastal region of southwestern British Columbia, soil water drainage is a major component of water balance for the root zone of forested soil and deserves further study. The time trends of soil water drainage were found to be similar to that of streamflow from the small watershed containing the study site. This suggests that the geologic, edaphic, topographical, climatological conditions favor a large and direct contribution of root zone soil water drainage to streamflow. / Forestry, Faculty of / Graduate

Conselho Nacional de Desenvolvimento Científico e Tecnológico / The human action induces changes in basins natural runoff. Flooding may become more intense, there may be more immediate and prolonged droughts, an accelerated erosion process and water quality tends to deteriorate. Thus, this work exposes the need to know the impact in the runoff caused by the use change and land use with emphasis on urban space. So, this study aims to evaluate the differences in the runoff between two contiguous watersheds and with the same area: one being use predominantly agricultural and the other with primarily urban use. For this, it was necessary to evaluate the urbanization influence on the hydrologic regime through the water balance, using two small small watershed, one with 54% of its urbanized area - MU and the other covered with natural grassland and areas used for agriculture - MR, both with the same area of 2.31 km². More specifically, it seeks to quantify some components of water balance variables to estimate water availability and evaluate the small discharges, using monthly retention curves of the studied period. Through the analysis of hydrographs constructed with flow data collected simultaneously each hour in two small watershed of the events that generated the maximum discharges the different variations and the maximum discharge generated in the two small watershed were evaluated using some data collected during the period between January 2011 and October 2011. The global water balance showed that MU had a 5.1 times greater discharge than the MR, and in none of the months monitored MR showed a runoff of more than MU, with emphasis on January and February when it was found the greatest difference in more than 29 times. Analyzing globally the discharges with bigger permanence than 40%, MU presented a volume disposed 7.9 times greater than the MR and in none of months the volume disposed in MR was superior to that of MU, which can be explained by the hypothesis that MR has no underground contribution in its runoff, only in the vadose layer of the soil. Examining the hydrographs it was showed that the MU presents an acceleration in its runoff causing flow oscillations in smaller periods than MR presenting its flow peak up to four hours before the MR, maximum flow rate up to 13,743 L/s, while MR showed a maximum flow of 275 L/s, representing a difference of 66 times in the urbanization effect within the small watershed. Therefore, MU showed a higher runoff volume effect of urbanization within the small watershed and greater water availability than MR, while MR showed a higher loss by evapotranspiration and soil water infiltration than MU during the period of this research. / A ação antrópica provoca alteração no escoamento natural das bacias. As cheias podem se tornar mais intensas, as estiagens mais imediatas e prolongadas, os processos erosivos acelerados, enquanto a qualidade da água tende a deteriorar-se. Com isso, a questão que se coloca neste trabalho é a necessidade de se conhecer o impacto provocado pela mudança do uso e ocupação do solo, no escoamento, com ênfase no espaço urbano. Portanto, o presente trabalho objetiva avaliar as diferenças no escoamento entre duas bacias contíguas e com a mesma área: uma com o uso preponderantemente agrícola e outra com o uso primordialmente urbano. Para isso, buscou-se avaliar a influência da urbanização sobre o regime hidrológico por meio do balanço hídrico, utilizando-se duas microbacias, uma com 54% de sua área urbanizada - MU e a outra coberta por campo nativo e áreas utilizadas para agricultura MR, ambas com a mesma área de 2,31 km². Mais especificamente, busca-se quantificar algumas variáveis componentes do balanço hídrico para estimar a disponibilidade hídrica e avaliar as pequenas vazões, utilizando curvas de permanência. Por meio da análise de hidrogramas construídos com dados de vazão coletados simultaneamente, de hora em hora, nas duas microbacias, dos eventos que geraram as vazões máximas avaliaram-se as diferentes variações de vazão e as máximas geradas, utilizando os dados coletados no período compreendido entre janeiro e outubro de 2011. O balanço hídrico global mostrou que a MU apresentou um escoamento 5,1 vezes maior que a MR, e, em nenhum dos meses monitorados, a MR apresentou um deflúvio superior a MU, merecendo destaque os meses de janeiro e fevereiro, em que se constatou a maior diferença em mais de 29 vezes. Em relação às vazões com permanência maiores que 40%, analisando de forma global, a MU apresentou volume escoado 7,9 vezes maior do que a MR, e, em nenhum dos meses, o volume escoado na MR foi superior ao da MU, o que pode ser explicado pela hipótese de a MR não possuir contribuição subterrânea em seu deflúvio, somente da camada vadosa do solo. Já a análise dos hidrogramas mostrara que a MU apresenta uma aceleração em seu escoamento, fazendo com que ocorram oscilações de vazão em períodos menores que na MR, apresentando o seu pico de vazão até quatro horas antes do que a MR, vazão máxima de até 13743 L/s, enquanto a MR apresentou uma vazão máxima de 275 L/s, o que representa uma diferença de 66 vezes, demonstrando o efeito da urbanização dentro da microbacia. Portanto, para o período da pesquisa, a MU apresentou maior volume escoado pelo efeito da urbanização dentro da microbacia e maior disponibilidade hídrica do que a MR, enquanto a MR apresentou maior perda por evapotranspiração e infiltração de água no solo do que a MU.

Relationships between thunderstorm and watershed variables and runoff from or within semiarid watersheds at Walnut Gulch, Arizona were examined. Variables showing greater sensitivity to basin and storm size were better flow predictors. Stepwise regression with three increasingly nonlinear algebraic models showed mean storm depth was the best simple predictor of runoff. Predictions improved using storm volume, a product of storm depth and areal extent. Initial runoff to streams was best described as a highly nonlinear function of storm and watershed variables. Runoff from a basin was a more linearized function of similar variables. The above differences were ascribed to channel transmission losses, reductions in runoff moving down initially dry channels. For a given basin and small storms, loss to runoff ratios exceeded 10:1 and were highly variable. Ratios were similar and less than 0.5:1 for storms centrally located over a basin and generating sufficient initial runoff to minimize flow variation due to losses. Losses increased disproportionately with basin size. Antecedent rainfall and first summer flows also affected rainfall runoff relationships in a differential manner. Wet conditions enhanced runoff more from larger versus smaller storms. First summer flows were less than expected probably because of higher soil infiltration and channel losses at the onset of summer storms. Overall, as storm size decreased or basin area increased, initial runoff was more often a localized phenomenon and downstream flow more dependent on storm depth, extent, location, and seasonal timing and basin channel losses, but less dependent on antecedent rainfall. Consequently, storm depth accounted for only 60% to 70% of the variation in flows while storm volume, antecedent rainfall, channel losses, and first summer flows explained 80% to 90%. Finally, oversimplifying storm or watershed variables or analytical methods led to errors in assessing their affect on runoff. It was also determined that current arguments supporting a recommendation to delete smaller, frequent annual floods to better fit remaining data to flood frequency curves were oversimplified. Distributed rainfall - runoff models with channel losses and regional storm depth - area - frequency data may be the way to develope flood curves for semiarid basins with short runoff records.

Forested watersheds play a dominant role in the global hydrological cycle. Very few experimental observatories especially in tropical forested regions of India have been undertaken. This study has been initiated for this reason and to gain insights into functioning of the hydrological system in such climatic conditions. This study involves experimental setup of a watershed, it’s monitoring till date, modelling of the hydrological processes observed and the challenges in modelling components of the water balance in this watershed. A Small Experimental Watershed of 4.3 Km2 was set up at Mule Hole, in South India along the Kerala-Karnataka State borders, and is situated inside the Bandipur National park. After an overview of watershed studies, review of literature related to forest watershed studies and processes in the first two chapters, Chapter 3 introduces the study area, Mule Hole Experimental Watershed and explains the methodology used to study this watershed. Model SWAT was used initially to simulate the water balance components. A brief description of the model, methodology adopted and discussion on the results obtained is presented in Chapter 4. The watershed initially modelled as an ungauged watershed using the default parameters in the model, simulated very high groundwater contribution to the runoff. The calibrated model although performed favourably for annual average values and monthly calibration, the daily calibration was unsatisfactory. An auxiliary study on quantification of actual and potential evapotranspiration (ET0) has been carried out in Chapter 5 . Ten methods including Penman-Montieth were compared and evaluated for efficacy of the methods. All methods except for Hargreaves method showed agreement with the Penman-Montieth for annual average values. Priestly-Taylor method was found be the best estimator in comparison with Penman-Montieth method, when used to estimate AET. Adjusted Hargreaves and FAO Blaney -Criddle method were found to be very useful when few or limited climatic data were available for estimation of Potential evapotranspiration. A multidisciplinary approach of estimating recharge consisting of chloride mass balance technique coupled with study of water table fluctuations and groundwater flow analytical modelling has been attempted in Chapter 6. Direct and localized recharge was estimated at 45 mm/yr and indirect recharge 30 mm/yr for the monitored years in the watershed. The low values of recharge rates implied an unexpected very high evapotranspiration rate. It may be inferred that in the absence of groundwater flow to the stream, the recharge joins groundwater flow as outflow of the hydrologic system. An integrated lumped model incorporating the regolith zone and the capability of the tree roots to access this store is presented in Chapter 7. The model was able to simulate the pattern of lag-time between water table rise was observed in shallow piezometers in comparison with hillslope piezometers. The patterns of water table variation among the different hillslope piezometers suggest that they are linked with local processes and not by a regional aquifer dynamics. This study shows that water uptake, combined with the spatial variability of regolith depth, can account for the variable lag time between drainage events and groundwater rise observed for the different piezometers. Chapter 8 discusses the results, conclusions derived from this study and possibility of further scope of studies.

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.