The Sevier River Basin situated in south central Utah is characterized by its semiarid climate, snowmelt-driven runoff, and high dependency on agricultural economy. High evapotranspiration and low precipitation make agricultural production challenging, but naturally stored water in the snowpack in the mountains alleviates water stresses during high water demand seasons. The snowmelt-driven river flow along the main channel is highly exploited for irrigation for farms near the Sevier River. Reservoir operations and river diversions result in heavily regulated flows from the upper to the lower basins. The return flows of over-irrigated water in the upper basin increase salinity of surface water. Long-term applications of salinity water in agriculture eventually produce high soil salinity in the agricultural areas near Delta in the lower basin, which deteriorated farmers’ crop productivity. Farmers cropping near Delta struggle with both water and salinity stresses. Indeed, crop prices and yields are always their concerns. For them, efficient water management can be achieved with consideration of hydrologic, agronomic, and economic aspects of water resources. The overall goal of this research was to develop a decision supporting framework for efficient water and land allocations that considered hydrologic processes, crop response to water in salinity-affected farms, and farmers’ profit and financial risk. This research introduces a methodology for predicting water availability in a given cropping year from the snowpack in the mountains, and agronomic simulations with satellite images follow for quantifying crop response to water. The hydrologic predictions and the agronomic simulations are finally incorporated into an economic analysis that provides efficient water and land allocations with multiple crop selections. In a rural river basin, data limitation is a common concern for water resources engineers; thus simple but robust methodologies are proposed for hydrologic prediction. In the same context, satellite images are used for the estimation of crop yields in individual farms near Delta with no prior crop experimental plots. Historical records of crop prices are used for the economic analysis. The methodologies developed in this research provide a comprehensive decision analysis framework for efficient water management where water is scare and available from snowmelt only, the economy depends on agriculture only, and salinity is present in both soil and water due to long-term irrigation. The case study is for the agricultural area near Delta in the Sevier River Basin, but its applicability is not limited and is flexibly applicable to other agricultural regions.

Thesis (M.S.)--Oregon State University, 2007. / Printout. Includes bibliographical references (leaves 198-204). Also available on the World Wide Web.

Thesis (Ph.D.)--Australian National University, 2002. / Australian Digital Theses Program. Includes bibliographical references (leaves 343-380).

Field scale research shows concentrated flow paths (CFPs) are prevalent in agricultural watersheds. They are an important source of soil erosion in cropland and significantly contribute to the transport and delivery of agricultural pollutants such as sediment and nutrients to nearby water resources. High resolution LiDAR data have enabled the investigation of the prevalence of concentrated flow at a large geographic extent. This study focused on identifying CFPs in 389 agricultural fields in Jackson County in southern Illinois and estimating the contribution of the CFPs to drainage of the fields. Addressing the lack of literature on factors influencing CFP characteristics, this study also investigates various topographical and soil factors that influence CFP development. LiDAR derived DEMs with a cell resolution of 3 meters were used to identify areas of flow concentration and delineate a drainage basin of each CFP using the Hydrology tools in the Spatial Analyst toolbox in ArcMap 10.3.1. Information on the topographical and soil characteristics were obtained from the DEMs and SSURGO database using the Soil Data Viewer 6.2 extension for ArcMap. Multiple regression analysis in SAS v. 9.4 was used to identify factors influencing CFP characteristics, while CART analysis in R v. 3.3.1 was conducted to detect linear dependencies among predictor variables. An average of 5 CFPs per agricultural field were observed in the study area with a minimum of 0 and maximum of 17 CFPs, but only two fields had no CFPs indicating a high prevalence of CFPs throughout the study area. The mean percent of field area drained by CFPs was estimated to be 81 percent with minimum of 36 percent and ii maximum of 100 percent. The majority of the fields, 85 percent, had more than 70 percent of their area drained by CFPs. Statistically significant regression equations were found for all CFP characteristics with slope, LS factor, K factor and organic matter as the factors influencing CFP characteristics. However, the factors only explained 2 to 22 percent of variation observed. Both multiple regression and CART analysis indicated slope as the most important influencing factor. Variation in CFP characteristics followed regional trends with higher values in the floodplain region and lower values in the rough hills region suggesting residual variation could be explained by other environmental factors along with topographical and climatological factors which were not included in the study. Results from this study highlight the prevalence of CFPs at a regional scale and their substantial contribution to field drainage identifying a need for research in quantifying the impacts of CFP on soil loss and water quality. This study also reports a need of future research to identify important factors controlling CFP formation and development that could help build empirical and physical models to accurately predict CFP locations and morphology. Such information could be useful in designing and targeting conservation practices that protect both soil health and water quality.

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In this study, we discussed the impacts of human water consumption to the nutrient burden in a river estuary, and used Huanghe River as a case study. The agricultural water consumption from the Huanghe River has significantly decreased the natural water flows, and the amount of water consumption could be almost twice as high as the water entering into the estuary. According to our calculation, agricultural water usage decreased TN outflows by 6.5 x 104 Mg/year and TP outflows by 2.0 x 103 Mg/year. These account for 74% and 77% of the total output loads. It has been widely reported that the majority of the rivers in northern China were severely polluted by nutrients. Its implication on the budget of nutrient in the estuary ecosystem is not well characterized. Our study showed that the discharge of nutrients in the coast waters from polluted rivers was over concerned. Nutrients in the polluted rivers were transported back to the terrestrial systems when water was drawn for human water consumption. The magnitudes of changes in riverine nutrient discharges even exceed the water-sediment regulation trails in the Huanghe River. It has non-negligible impact on estimating the nutrient burden in costal water ecosystem.

Ozonation has been utilized for water treatment for over 100 years. During that time, the range of applications has grown considerably, and includes the remediation of nursery and greenhouse irrigation water. Ozone is dissolved into irrigation water to kill pathogens and degrade chemical contaminants. By convention, growers remove ozone from solutions, prior to distribution to the crop, to avoid phytotoxic effects. The available literature regarding aqueous ozone (O3(aq)) phytotoxicity is limited, making this a sagacious practice, although the removal does preclude any ancillary benefits beyond the point of treatment. The effects of applying O3(aq) under two irrigation systems are examined. Initial studies suggested O3(aq) concentrations as high as 20 mg⋅L-1 could be applied directly to mineral wool substrate in a limited (one time) fashion without a negative response. To be effective as a remediation tool, however, ozone would need to be applied more frequently (e.g. daily). The effects of daily O3(aq) application, via drip irrigation in mineral wool hydroponic tomato culture, was examined. In the first of two studies, daily applications of 3.0 mg⋅L-1 O3(aq) elicited an overall positive growth response. In a follow-up study, 6.0 mg L-1 elicited a negative response. Nursery operators often utilize overhead irrigation. A study was conducted to determine if overhead irrigation utilizing O3(aq) was compatible with select woody perennial nursery species. The amount of ozone lost from solution during application was examined, as well as crop response to the ozone environment generated. It was shown that 60 to 70% of the ozone was unaccounted for at canopy level, while phytotoxic effects were elicited at emitter concentrations above 1.5 mg L-1. Marchantia polymorpha is a significant weed species in greenhouse and nursery production; a species with few control options. Anatomical features of M. polymorpha suggested sensitivity to O3(aq). Studies were performed to examine contact time (CT) and exposure frequencies required for M. polymorpha suppression. A CT of 0.84 mg⋅L-1⋅min at an application frequency of 3-times/week achieved measurable suppression. / Natural Science and Engineering Research Council (NSEARC); Ontario Ministry of Agriculture Food and Rural Affairs (OMAFRA); Ontario Centres of Excellence (OCE); Purification Research Technologies INC (PRTI); Flowers Canada (Ontario).

No description available.

To achieve economic development, regional authorities have to address issues that relate to climate change, efficient information flow in the market place, and health care. This dissertation presents three essays on current issues of concern to economic development in Africa. Climate change is examined in terms of its effects on the Egyptian agricultural sector; transmission of world price to small scale growers is examined in Uganda; and the benefits of insecticide-treated bed nets use is examined in Africa. In essay I, to address the impact of climate change on the Egyptian agricultural sector under alternative population growth rates, water use and crop yield assumption; the Egyptian Agricultural Sector Model (EASM) is updated and expanded to improve hydrological modeling and used to portray agricultural activity and hydrological flow. The results indicate that climate change will cause damages (costs) to the Egyptian agricultural sector and these will increase over time. Egypt may reduce these future damages by controlling its population growth rate and using water conservation strategies. In essay II, I use vector autoregressive analysis to examine the transmissions of price information to Uganda coffee growers; using monthly coffee price data on retail, futures, farmgate and world prices from 1994 to 2010. Improved transmission of world prices to farmers may increase their decision making to obtain a better market price. Directed acyclic graphs reveal that there is a causal flow of information from the indicator price to the London futures price to the Uganda grower?s price in contemporaneous time. Forecast error variance decomposition indicates that at moving ahead 12 months, the uncertainty in Uganda grower price is attributable to the indicator price (world spot price), own price (farmgate), London future and Spain retail price in rank order. In essay III, the cost of malaria in children under five years and the use of insecticide treated bed nets is examined in the context of 18 countries in Africa. I examine the direct and indirect cost of malaria in children under five years and the benefit of investing in insecticide treated mosquito nets as a preventative strategy in 18 African countries. The results indicate that the use of mosquito treated nets reduces the number of malaria cases in children; and this can induce 0.5% reduction in outpatient treatment costs, 11% reduction in inpatient treatment costs, 11% reduction in productivity loss, and 15% reduction in disability adjusted life years (DALY) annually.

Magister Economicae - MEcon / In this thesis, I explore the allocation and use of water for productive and domestic purposes in the village of Siyandhani in the Klein Letaba sub-area, and how the allocation and use is being affected by new water resource management and water services provision legislation and policies in the context of water reform. This problem is worth studying because access to water for domestic and productive purposes is a critical dimension of poverty alleviation.The study focuses in particular on the extent to which policy objectives of greater equity in resource allocation and poverty alleviation are being achieved at local level with the following specific objectives: to establish water resources availability in Letaba/Shingwedzi sub-region, specifically surface and groundwater and examine water uses by different sectors (e.g. agriculture, industry, domestic, forestry etc.,); to explore the dynamics of existing formal and informal institutions for water resources management and water services provision and the relationship between and among them; to investigate the practice of allocation and use of domestic water; to investigate the practice of allocation and use of irrigation water.The study concludes that there is a problem of water scarcity in the study area and that the water scarcity is caused by the growth in the population, specifically in the Giyani area; these problems are exacerbated by financial and institutional obstacles within local institutions of governance. The water scarcity is not, therefore, natural but anthropogenic in nature.The water scarcity is not felt by all sectors, however: some farmers have access to water for irrigation, while many others face great challenges in their farming activities.Overall, people in Siyandhani and surrounding villages surrounding villages in the Letaba Catchment do not have access to water because of human action, hence the use of the concept of manufactured scarcity. The lack of access to water, it is argued,leads to the violation of the human right to water. This study concludes that water reform, which is widely seen as a priority for South Africa, has not yet reached the villages of the Klein Letaba.