Federal and state programs have encouraged farmers in the Mississippi Delta region to implement best management practices (BMPs) to promote soil and water conservation. An onarm water storage (OFWS) system is a structural BMP that has several potential benefits, namely, the ability to capture and reuse rainwater and tailwater runoff, provide supplemental water for irrigation, reduce groundwater withdrawals, and improve downstream water quality. However, research demonstrating these benefits and providing new insights for downstream water quality improvement and nutrient-rich runoff management is limited. This dissertation addresses these research gaps by examining the ability of OFWS systems to mitigate off-site nutrient movement, analyzing the impacts of rainfall characteristics on the ability of OFWS systems to reduce NO3-N, studying the hydrological and physical-chemical characteristics of the volume of water exiting an OFWS system, and using the AnnAGNPS model to simulate runoff, nutrient, and sediment loads entering a tailwater recovery ditch and identify the critical contributing areas of non-point source pollution. Significant seasonal water quality improvements were observed at different locations throughout the OFWS system, and more importantly, highlight downstream nutrient reduction, particularly during winter and spring. However, recurrent and high intensity rainfall events can minimize the system’s effectiveness in reducing downstream nutrient pollution. The NO3-N concentrations observed in the ditch were strongly dependent on antecedent hydrological conditions with characteristics of next-to-last rainfall events playing a more influential role. The nutrient load was greater in winter, as this season produced the highest effluent discharge. Agricultural fields draining to the outlet of the system produced 7.1 kg NO3-N ha-1yr-1 and 2.3 kg TP ha-1yr-1 that was discharged with outflow events. AnnAGNPS simulations showed that larger fields coupled with poorly drained soils resulted in higher runoff, and this condition mirrored the annual rainfall patterns. High nitrogen loss was due to fertilization of corn and winter wheat. TP and sediment loss patterns were similar and influenced by the hydrological condition. This study can be used by stakeholders and agencies to better identify where these systems can be implemented to improve water quality and offer a supplemental source of surface water.

M. S.

Water conservation efforts have led to a decrease of flow rates in buildings, increasing water retention time (WRT) and sometimes opportunistic pathogens (OPs) growth. A novel experiment with replicated distal pipes operated at commonly used flow rates was designed to evaluate the effects of water age, flush frequency, flow rate, pipe diameter, water temperature, disinfectant residual presence, and microbial regrowth in hot and cold pipes. In cold water, total bacterial regrowth was a function of water age, plateauing after approximately 6 days at cell counts 20 times higher than influent water with minimal disinfectants. In warm (40 °C) water, most regrowth occurred in the heater tank, reducing the relative growth in the pipes. When cold water with ~1 mg/L chloramine was present, cold-water total bacteria regrowth plateaued after about 2 days WRT with cell counts 14 times higher than influent water, but regrowth still occurred in the heater tank. With 1 mg/L chloramine and elevated heater temperature (60 °C), regrowth in the tank was suppressed and cell counts in the pipes increased 82 times above cold-water influent levels at 7.5 days WRT. Legionella spp. and Mycobacterium spp. demonstrated opposite responses to flow rate with chloramine minimization. The highest levels of Legionella spp. (1.7 log higher than influent) were present when flow velocity was >2 feet per second (fps), but the highest levels of Mycobacterium spp. (1.5 log higher than influent) were observed at the lowest flow velocity (0.33 fps). This study highlights the tradeoffs between water conservation and water quality. / Master of Science / Regulations that decrease flow rates of faucets and showers have driven water conservation in buildings, increasing the time water sits in pipes and tanks (i.e., water retention time or WRT) elevating the likelihood of harmful bacterial growth. A novel faucet rig was designed to carry out a comprehensive experiment revealing the combined effects of WRT, flush frequency, flow rate, pipe diameter, water temperature, and disinfectant residual presence on water quality at the tap. In water without disinfectant, growth in cold water pipes increased with WRT, but in hot water the growth of bacteria occurred mostly in the warm water tank at 40 °C, which is a temperature known to leave a system vulnerable to bacterial growth. Cold pipes with a disinfectant residual saw a decrease in bacterial regrowth in comparison to cold pipes without disinfectant. However, if there was a disinfectant residual and an elevated water heater temperature set point in the tank, regrowth occurred when water was in the pipes at room temperature and there were lower disinfectant residuals. Potentially harmful bacteria, like Legionella spp. and Mycobacterium spp., which cause Legionnaires' disease and nontuberculous Mycobacteria (NTM) infections, grew more readily at higher flow rates, whereas others grew less readily, but all harmful bacteria were reduced by lowering WRT to less than ≈ 2 days and maintaining the water at 60 °C with a disinfectant. This study has important implications for regulations requiring minimum disinfectant levels to buildings, faucet flow rates regulations, and design and operation of building plumbing systems.

M. S.

Since this broad subject is now neither organized nor outlined, there is a particular need for a definite outline of material for teaching this course at Virginia Polytechnic Institute. The proposed outline, by eliminating overlapping subject matter, and by making use of the great abundance of experimental data and written material, will make it possible to give students a broad understanding of the fundamentals of the course in the short time allotted. This arrangement will also eliminate the necessity for students to purchase text books covering all the divisions, which is undesirable from an economic standpoint even if satisfactory texts were available. For the above reasons there is an urgent need to have in the department an up-to-date outline for the use of any instructor teaching the course. The purpose of this outline is to enable the Agricultural Engineering Department to offer an improved course in soil and water conservation. In order to promote more efficient teaching, it seems desirable to combine the subjects of Soil Erosion, Drainage, Flood Control, and Irrigation in one course. The flexible nature of the outline method of presentation permits the inclusion of up-to-date material and will facilitate future revision. The organization and development of material is, therefore, taken up as a thesis subject in the hope that a real contribution may be made to the work of the department, as well as to any instructor desiring to install a course of this kind. / Master of Science

Pollinators provide key ecological services. With one-third of our global food production dependent on pollinators, maintaining healthy pollinator communities is vital. Bees are the most pervasive and effective pollinator species, yet are currently declining worldwide, with the main cause linked to habitat loss. To combat this decline, researchers are turning to suburban landscapes to aid in pollinator conservation. Incorporating native plants into suburban landscapes has been shown to benefit pollinators. However, there is a lack of information on how different landscape designs and growing conditions influence pollinator communities. To better understand whether native plants can effectively improve suburban pollinator habitats, this research asked: 1) how does irrigation and soil composition influence the availability of floral resources, 2) which plants attract the greatest number and diversity of pollinators, and 3) how do native vs non-native landscape designs impact a residential neighborhood’s ability to support pollinator communities? Using 27 different native plant species that were subjected to a combination of irrigation and compost treatments, we examined plant-pollinator interactions in 16 fully replicated and randomized experimental plots. Additionally, we compared the pollinator communities of two newly developed neighborhoods - one using traditional, non-native plants and the other incorporating native plants into their landscape design. Pollinators were sampled during the spring, summer, and fall of 2022-2023 through visual counts of pollinators visiting open flowers. Blooming flowers for each plant species were counted concurrently to determine floral abundance. Compost addition at planting greatly increased both floral and pollinator abundance over two years, but regular irrigation did not have a clear impact. Native-based landscapes had significantly higher pollinator abundance and diversity when compared to traditional landscape designs. The results of this study show the benefits of incorporating native plants into suburban landscapes and their potential for supporting both water conservation and pollinator communities.

Call number: LD2668 .T4 1986 H64 / Master of Science / Civil Engineering

A research report submitted to the Faculty of the Built Environment and Engineering, University of the Witwatersrand, in partial fulfillment of the requirement for the degree of Master of Science in the field of Development Planning (MSc DP) August 2015 / Since the democratic transition in 1994, the role of local government has changed dramatically. Local governments are now expected to play a far more active role in their constituencies. As such, municipalities are expected to implement broader national policies and legislatures. The literature reviewed as part of the research indicated that most municipalities are faced with inadequate performance skills to manage and sustain their projects. This particular study seeks to understand the institutional and human resources strengths and weaknesses that help or hinder Sedibeng municipality to actively pursue water conservation through implementing Integrated Water Resources Management (IWRM) principles. In pursuit of this purpose, a qualitative research approach was adopted with interviews conducted with Sedibeng Municipality’s seven senior officials and community members. The main findings of this study revealed that the key technical department of the water sector in Sedibeng has capacity challenges at individual and organizational level. Of special concern is the failure of the municipality to give ongoing training to staff, so as to pass on modern advanced knowledge and new technological innovation skills. This is further compounded by the mismatch between the qualifications and job descriptions of some staff members. The study also finds that public-private partnership between the municipalities and private companies is needed in the water sector to promote water conservation and thus provide a better level of service delivery. The research concludes that institutional capacity is a prerequisite for the implementation of IWRM principles. In regard to this study, it has been established that to some extent Sedibeng District Municipality has the required institutional capacity in terms of organizational arrangement to harness the principles of IWRM. The accomplishment of IWRM depends profoundly on financial and human capacity of each municipality. Therefore, the key recommendation is that the municipalities should employ individuals based on merit and work experience to ensure efficient management of funds and effective execution of water related projects. Key words: Water Conservation, IWRM, Institutional capacity, Sedibeng, Emfuleni

A Study to Develop Strategies for Proactive Water-Loss Management Hyun Jung Park Directed by Dr. Mary Beth Walker Water conservation is one of the important policy concerns. However, most water conservation practices have focused primarily on reducing use by customers. Since a large amount of water lost in supply systems causes water providers to lose money, resources, and reliability, and the current passive approach cannot deal with water losses effectively, a proactive approach is necessary for water-loss management. The goal of this study is to help policymakers and water utilities develop strategies that proactively solve water losses. To develop strategies for water-loss management, it is essential to identify key factors that determine the level of water losses as well as the factors that encourage the adoption of the innovative control practices. Using three different datasets and statistical methodology, this study analyzed the factors associated with water losses and utilities responses to the problems. Based on case studies, this study explored managers perceptions about the adoption of water-loss management and identified organizational characteristics that may influence managements decisions to adopt such strategies. Operational and Maintenance (O and M) factors had the most significant impacts on water losses. In particular, system size, represented by total production or population served, and infrastructure rehabilitation were crucial factors. The effects of some internal factors on water losses were predicted but those of several internal factors were rather unclear and relatively complicated. This study confirmed that utilities were more likely to be motivated to combat water losses if certain external conditions, such as higher water demand, limited resource availability, and institutional pressure exist. This study found several internal and external factors associated with the adoption of proactive water-loss management; however, internal factors seemed to dominate in the decision-making processes over such adoption. The utilities that have already adopted proactive water-loss management seem to be more amenable to adopt new practices because they have certain characteristics and their managers have more positive perspectives. The findings suggest several policy implications and recommendations for the water industry. Finally, this study discussed limitations of the study, and suggestions for further studies.

Thesis (MScEng (Civil Engineering))- -University of Stellenbosch, 2011 / ENGLISH ABSTRACT: The limited water supply and an increasing water demand means that the effective management of water resources becomes much more important than in the past. The implementation of water demand management / water conservation (WDM/WC) projects are usually used as a crisis management tool to reduce immediate water shortage and to allow time for the planning and construction of infrastructure to increase water supply. It is however possible to incorporate WDM/WC into integrated water resource management and to use WDM/WC as an economic viable option for the upgrade of infrastructure to balance supply and demand. Existing economic evaluation methods to compare different options with each other were used to evaluate WDM/WC measures. Literature showed that to perform an economic evaluation of WDM/WC measures, the costs associated with the implementation of the WDM/WC measures, as well as the expected water saving from the implementation of the WDM/WC measure, must be known. Models were developed to estimate the expected water savings from different WDM/WC measures. The economic impacts of specific WDM/WC measures were investigated by using these models. Different economic models were developed to perform an economic evaluation of WDM/WC measures. WDM/WC measures were evaluated in terms of its economic feasibility. Economical evaluations of WDM/WC measures were also done as an alternative to the upgrading of infrastructure. In the last evaluation, the financing of WDM/WC measures through the deferral of capital cost, was investigated. Case studies from literature, where costs as well as water savings were available, were used to evaluate these WDM/WC measures by using the developed economic models. Cost estimates for the upgrading of infrastructure, to supply an equal amount of water as the water saving achieved in each case study, were done. These estimates were used to compare WDM/WC measure with the upgrading of infrastructure. / AFRIKAANSE OPSOMMING: Daar word al hoe meer druk op bestaande hulpbronne geplaas om voldoende water te lewer. Die fokus skuif na effektiewe bestuur van hierdie hulpbronne. Wateraanvraagbestuur/ Waterbewaring (WAB/WB) projekte word geïmplementeer om krisisse van water tekorte aan te spreek en tyd te wen om nuwe hulpbronne te ontwikkel. Dit is wel moontlik om WAB/WB in geïntegreerde waterbron bestuur in te sluit en WAB/WB as ʼn ekonomiese alternatief tot kapitale investering aan te wend. Om die ekonomiese aspekte van WAB/WB te ondersoek, is daar op bestaande ekonomiese evaluerings metodes gefokus om verskillende opsies met mekaar te vergelyk. Uit die literatuur is gevind dat die belangrikste aspekte vir die ontleding van WAB/WB alternatiewe i.t.v. hul ekonomiese waarde, die koste van implementering van die WAB/WB alternatief is en die waterbesparing wat deur die implementering van die WAB/WB alternatief verkry word. WAB/WB modelle is ontwikkel om die verwagte water besparing van bepaalde WAB/WB alternatiewe te beraam. Die moontlike ekonomiese impak van bepaalde WAB/WB alternatiewe is deur die gebruik van hierdie modelle ondersoek. Ekonomiese evaluerings modelle is opgestel om WAB/WB alternatiewe te ontleed. WAB/WB alternatiewe kan as ʼn ekonomiese haalbare projek geïmplementeer word waar die kostes van die waterbesparings meer as die kapitale koste van die projek is. WAB/WB alternatiewe kan ook meer ekonomies as die ontwikkeling van nuwe bronne of opgradering van ʼn bestaande netwerk wees. Laastens is die moontlikheid om WAB/WB as ʼn alternatief te finansier deur die besparing wat bereik kan word deur ʼn kapitale projek uit te stel, ondersoek. Gevalle studies uit die literatuur, waar die kostes en waterbesparings bekend is, is ontleed deur van hierdie ekonomiese evaluerings modelle gebruik te maak. Vir elk van die gevalle studies is ʼn koste vir die opgradering van die infrastruktuur beraam om die ekwivalente hoeveelheid water te voorsien as wat deur die WAB/WB alternatief bespaar is.