<p> The Sierra Nevada is estimated to provide over 66% of California's water supply, which is largely derived from snowmelt. Global climate warming is expected to result in a decrease in snow pack and an increase in melting rate, making the attenuation of snowmelt by any means, an important ecosystem service for ensuring water availability. Montane meadows are dispersed throughout the mountain range providing wildlife habitat, water filtration, and water storage. Despite the important role of meadows in the Sierra Nevada, the majority are degraded from stream incision, which increases volume outflows and reduces overbank flooding, thus reducing infiltration and potential water storage. Restoration of meadow stream channels would therefore improve hydrological functioning, including increased water storage. The potential water holding capacity of restored meadows has yet to be quantified, thus this research seeks to address this knowledge gap by estimating the restorable water volume due to stream incision. More than 17,000 meadows were analyzed by categorizing their erosion potential using channel slope and soil texture, ultimately resulting in six general erodibility types. Field measurements of over 100 meadows, stratified by latitude, elevation, and geologic substrate, were then taken and analyzed for each erodibility type to determine average depth of incision. Restorable water volume was then quantified as a function of water holding capacity of the soil, meadow area and incised depth. Total restorable water volume across meadows in the Sierra Nevada was found to be 120 x 10⁶m³, or approximately 97,000 acre-feet. Using 95% confidence intervals for incised depth, the upper and lower bounds of the total restorable water volume were found to be 107 x 10⁶m³ &ndash; 140 x 10⁶m³. Though this estimate of restorable water volume is small in regards to the storage capacity of typical California reservoirs, restoration of Sierra Nevada meadows remains an important objective. Storage of water in meadows benefits California wildlife, potentially attenuates floods, and elevates base flows, which can ease effects to the spring snowmelt recession from the expected decline in Sierran snowpack with atmospheric warming.</p>

<p> In at least 45 low- and middle-income countries, piped water systems deliver water for limited durations. Few data are available of the impact of intermittent water supply (IWS) on the water quality and quantity delivered to households. This thesis examines the impact of intermittently supplied piped water on the quality and quantity of water delivered to residential taps in Hubli-Dharwad, India, when compared to continuous piped water supply. A framework for understanding the pathways through which IWS can impact water quality is first developed. The extent to which contamination occurs in Hubli-Dharwad is quantified by comparing microbial water quality throughout the distribution system in an intermittent system and a continuous system in the same city. The mechanisms affecting water quality in the IWS network in Hubli-Dharwad are identified by measuring changes in water quality over time using continuous measurements from pressure and physico-chemical sensors paired with grab samples tested for indicator bacteria. In the final chapter, a new method of measuring household water consumption in an IWS when supply durations are limited and few metered data are available is developed. This thesis showed that the intermittent supply was frequently subject to contamination in the distribution system and that households with intermittent supply consumed limited quantities of water. While these results demonstrated that converting to a continuous water supply can improve water quality when compared to intermittent supply, this conversion may not be possible in the near future for resource-constrained towns and cities. This thesis contributes to knowledge of the mechanisms causing contamination and constricting water access in IWS systems, which can help improve systems to ensure that people with piped water receive water that is reliable, safe, and sufficient.</p>

<p> The abstract is not available from PDF copy and paste.</p>

<p>Dissolved organic matter (DOM) is an important component of nutrient cycling and energy transfer within and between ecosystems. Understanding controls over the magnitude and quality of DOM that is transferred from soils to surface water is needed to better characterize the terrestrial-aquatic carbon flux and effects of terrestrial DOM on downstream ecosystems. A meta-analysis of the response of in-stream dissolved organic nitrogen concentration (DON) to high flow events indicates that DON typically increases with flow across a wide range of ecosystem types, likely as novel DOM sources in the landscape are mobilized and transported to streams and rivers. Mechanisms controlling DOM export, including dissolved organic carbon (DOC) and DON concentrations and the quality of DOM, were examined in a small agricultural catchment in eastern Washington State. In the soil column, DOC concentration declined and source of DOM shifted from humic-like and plant-derived to microbially-derived with depth through the profile. Across seasons and years, DOM exported via drain discharge during low flows resembled that found deep in the soil profile, and DOM exported during high flows suggests topsoil and litter sources contribute to export. A simple mixing model suggests that litter leachate can contribute over 50% of DOM during peak flow. Based on modeled contributions of litter, topsoil and subsoil DOM during storm events, DOC concentration is over-predicted, except for peak flows, suggesting removal via sorption and/or microbial decomposition in the soil column control DOC export on the timescale of events. Although the character of exported DOM shifts with flow conditions, laboratory incubations suggest bioavailability to the stream sediment microbial community is consistently low, with a maximum of 7% loss over 6 days, indicating exported DOM is likely transported beyond the immediate stream reach. An analysis of anticipated effects of climate change on the flow regime in the catchment projects the wettest years to become more variable, with non-linear effects on the magnitude of DOC export. Finally I explore how climate change assessments can be incorporated into nonpoint source nutrient management plans, despite current uncertainty about the magnitude and timeframe of climate effects on nutrient loading.

<p> The theme that binds together the four papers in this dissertation is the tracking of physical quantities of water used by industries in the economy, and an exploration of whether and how this tracking could be helpful in informing water policies, as applied to the state of Nevada or sub-regions of Nevada. The concept of water footprints has been wildly popular in disciplines outside of economics and has been used to help make policy decisions normally considered to lie within the economist's realm. Yet many economists shun 'footprints' in general and water footprints in particular, seeing them as descriptive methods that have little or nothing to add to policy analysis. This thesis attempts to bridge a gap between economists, engineers and planners and the popular imagination about what economic concepts footprints are related to and how they can best be used in policy analysis.</p>

Access to safe and clean water is a problem in many countries in the world, especially sub-Saharan Africa. The urgency of the was recognized by the United Nations through its 2008 Millennium Development Goals, which were recently replaced by the new Sustainable Development Goals. Lack or poor access to clean water not only creates conflicts and rifts among the people, but also makes them more susceptible to a wide assortment of water borne diseases. The purpose of this dissertation is to complete a pilot study of ways of thinking and actions of a small group of people from Falifah, a village in The Gambia, who suffered from lack of access to safe and clean water. During my fieldwork in Falifah, I helped the community install a water filtration system in the village, and explored its value in improving the lives of the villagers. In particular, I conclude that village gained a sense of empowerment, for the water filtration system offered them the opportunity to become intimately involved in its implementation and its continued sustainability. This is especially important for women, given the long history of patriarchal control in this African village and many others like it.

The purpose of this study was to investigate the levels and quality of groundwater in a farming area to the north of Doha, the capital of the State of Qatar. Two rows of about five wells were selected, the lines being more or less parallel to each other, about 30 km apart, running for 45 km inland from the east coast. Vertical electrical sounding surveys were undertaken and groundwater samples were taken from these wells in winter and in summer. The water was chemically analysed, and the results formed the basis for a hydrogeochemical modelling exercise. The results of the geophysical and geochemical surveys indicate that there is a seasonal vertical and lateral migration of the fresh water/salt water interface in winter before the rainfall replenishes the groundwater aquifers. The geochemistry of the groundwater indicate that there is a gradual decrease of cations and anions, particularly Na+, cr, S04, and HC03-, together with a decrease in conductivity CEC), total dissolved solids (TDS) and sodium absorption ratio (SAR) from the coast inland. There is an upconing which brings the saline water to the surface near the middle of the southern profile in both seasons. In both profiles the fresh water/salt water interface migrates inland due to the excessive extraction of fresh water from the wells.

Doctor of Philosophy / Department of Geography / Charles W. Martin / Disturbance regimes are important determinants of both terrestrial and aquatic ecosystem structure and function. Disturbances may linger in the landscape and lag temporally, influencing stream ecosystem form and function for decades, if not centuries. The recent enhanced Mountain Pine Beetle (MPB) infestation in pine forests of the Rocky Mountain region has resulted in extensive tree mortality, producing the potential for significant increases in carbon supply to stream channels. To better understand MPB impacts on in-stream large wood (LW), a census was conducted in 30 headwater streams within the Medicine Bow National Forest in south-central Wyoming, across the temporal spectrum from early- to late-stage MPB-infestation. A subset of those streams exhibiting mean conditions at each level of infestation was surveyed to determine any significant differences in channel morphology or aquatic ecosystem function. Results indicate that wood loads related to the MPB-infestation significantly increase with time since initial infestation. However, even in late-stage infestation streams, many of the fallen MPB-killed trees are bridging across the channels and have yet to break and ramp down sufficiently enough to enter between the channel margins. Wood loads will continue to increase as more trees fall and bridging pieces decompose, break and then enter the channel. Measurable increases in the amount of LW with time since initial beetle infestation have both positive and negative effects on channel form and function. Although forest MPB-infestation has peaked in the study area, streams are still early on a curve of rapidly increasing wood loads that are beginning to affect streams and have the potential to dramatically increase the carbon base of regional stream ecosystems.

A general multimedia mass balance model was developed for Big Dam West, Kejimkujik Park, Nova Scotia to predict mercury (Hg) flux and fate in lakes. This model can be used as a screening-level tool by researchers with little to no modeling experience. The model requires no recalibration when applied to other lakes and few input variables (i.e., concentration of Hg in air and inflow water, lake and inflow water suspended particulate matter (SPM), lake temperature, mean depth, surface area, volume, precipitation rate, sedimentation and resuspension rate) need to be changed for any given location. Limits of this model termed "Hg Environmental Ratios Multimedia Ecosystem Sources" (HERMES) model were tested through reapplication and verification on Harp and Dickie Lake, along with Lake Ontario. The HERMES model predicts that small lakes with short water residence times and larger lakes with longer residence times are dominated by water inflow Hg concentration and atmospheric Hg concentration, respectively. For Lake Ontario, air concentrations of mercury appear to be most important. These results contrast with the currently held belief that the Niagara River is the main source of Hg to the lake. To improve model applicability to lakes with limited datasets, as was the case for many of the lakes used in this thesis, estimation methods were developed or adapted from the literature to estimate the most sensitive model input variables (i.e., water inflow Hg concentration, SPM, sediment resuspension rate, water inflow rate) when measured values are missing. Methyl mercury (MeHg) is the bioavailable form that accumulates through food webs, so estimation methods were developed or found to estimate the relative amount of methylated Hg in water inflow, water, and sediment as well. Error contributions to the model from estimation methods were tested through model application to thirty-five lakes in Ontario using three estimation methods (i.e., SPM, resuspension rate, water inflow Hg). The added value of SPM and resuspension rate estimates were assessed through comparisons with fixed values. A comparison between measured and predicted values for these lakes using these estimation methods revealed no significant difference for sediments. The HERMES model was used to derive water inflow Hg concentration values from measured sediment Hg. Regression of the derived water inflow Hg values against watershed and lake variables resulted in the following equation: log water inflow Hg concentration = (0.165 x log watershed area (km2)) + (0.102 x dissolved organic carbon (mg L-1)) -- (0.342 x log water inflow rate (m3 h-1)) + 0.000778 x direct runoff (mm yr-1)) + (0.0154 x mean lake depth (m)) + 0.492 (r2 = 0.68, p &lt; 0.0001). A comparison between the water inflow Hg concentration estimation method (i.e., equation) derived in this study and average measured values for sixteen lakes located in different parts of the world (e.g., Antarctica, Russia, Canada) showed a deviation of only 15.7+/-18.0%, and was within reported ranges (n = 6). This was found to be a significant (p &lt; 0.05) improvement over the previous estimation method for water inflow Hg concentration.

Water resources systems are designed to operate under a wide range of potential climate conditions. Traditionally, systems have been designed using stationarity-based methods. Stationarity is the assumption that the climate varies within an envelope of variability, implying that future variability will be similar to past variability. Due to anthropogenic climate change, the credibility of the stationarity-based assumptions has been reduced. In response, climate change assessments have been developed to quantify the potential impacts due to climatic change. While these methods quantify potential changes, they lack the probabilistic information that is needed for a risk-based approach to decision-analysis. This dissertation seeks to answer two crucial questions. First, what is the best way to evaluate water resource systems given uncertainty due to climate change? Second, what role should climate projections or scenarios play in water resources evaluation? A decision analytic approach is applied that begins by considering system decisions and proceeds to determine the information relevant to decision making. Climate based predictor variables are used to predict system hazards using a climate response function. The function is used with climate probability distributions to determine metrics of system robustness and risk. Climate projections and additional sources of climate information are used to develop conditional probability distributions for future climate conditions. The robustness and risk metrics are used to determine decision sensitivity to assumptions about future climate conditions. The methodology is applied within the context of the International Upper Great Lakes Study, which sought to determine a new regulation plan for the releases from Lake Superior that would perform better than the current regulation plan and be more robust to potential future climate change. The methodology clarifies the value of climate related assumptions and the value of GCM projections to the regulation plan decision. The approach presented in this dissertation represents a significant advancement in accounting for potential climate change in water resources decision making. The approach evaluates risk and robustness in a probabilistic context that is familiar to decision makers and evaluates the relevance of additional climate information to decisions.