<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.

Uncertainty in climate change plays a major role in watershed systems. The increase in variability and intensity in temperature and precipitation affects hydrologic cycle in spatial and temporal dimensions. Predicting uncertainty in climate change impacts on watershed systems can help to understand future climate-induced risk on watershed systems and is essential for designing policies for mitigation and adaptation. Modeling the temporal patterns of uncertainties is assessed in the New England region for temperature and precipitation patterns over a long term. The regional uncertainty is modeled using Python scripting and GIS to analyze spatial patterns of climate change uncertainties over space and time. The results show that the regional uncertainty is significant in variation for changes in location and climatic scenarios. Watershed response to climate change under future scenarios is assessed using hydrologic simulation modeling for the Connecticut River watershed. Changes in water budgets are assessed for each of the subbasins using spatial analysis and process modeling using GIS and Soil and Water Assessment tool (SWAT). The results show that climate change uncertainty in precipitation and temperature can lead to uncertainty in both quantity and quality in the watershed system. A spatiotemporal, dynamic model was applied to subbasins within the Chicopee River Watershed to estimate climate change uncertainty impacts at a micro scale. These changes were assessed relative to changes in land use and climatic change. The results show that there is a significant potential for climate change to increase evaporation, watershed runoff and soil erosion rates and this varied with climate change uncertainty. Finally, water sustainability gradient analysis was applied to the Volga River watershed in Russia to assess potential climate change impacts by combining with downscaled Global Circulation Model estimates and spatial assessment. Results show that runoff and evapotranspiration are projected to increase with potential for more localized floods and drought events effecting both water resources and food supply. Overall results show that climate change uncertainty can impact watershed systems and spatial and temporal assessments is important for developing strategies for adaptation to climatic change conditions at local and regional scales.

No description available.

The Weber Basin Water Conservancy District is a state institution, but its primary function is collecting money for the U.S. Bureau of Reclamation, to pay for the Weber Basin Project. Ditferent classes of water users pay markedly different fees for identical Project services. More than half of the water developed by the Project is not used consumptively, yet supply facilities continue to be built in the Basin because they are less expensive to their owners than prices charged for the underused capacity of the Project. Paradoxically, some Basin residents are bitterly resentful of both the District and the Bureau, claiming that water rights formerly their own have, by means of the Project, been stolen. That is, both the enemies and the proponents of the Project adhere to the Western orthodoxy that water i.s scarce and drought imminent. The principal difficulty of this investigation lay in identifying the nature of the problem, for the situation seemed full of contradictions. Consequently, the primary contribution of the dissertation is an explanation of Basin circumstances that accounts for arresting observations without inconsistency or contradiction. The most important hypotheses are, therefore, empirical, or historical and institutional. Economics, according to Richard T. Elya and Frank H. Knight, is a set of principles concerning what ought to be, not empirical description of what ~· Consistent with that perspective, once the nature of the problem is clear, application of economic principles is a prescriptive judgment of how the problem may be resolved. The most important empirical hypotheses are as follows: Water is not scarce in the Weber Basin; neither are storage and conveyance facilities. All are abundant, even redunda nt. Nevertheless, in combination with certain institutional arrangements and a sustained propaganda campaign, this very abundance contributes to persistence of the attitude that water is scarce. Redundant facilities the reby encourage even more unneeded development. What appears on first examination to be a case of misallocated water resources by discriminatory prices, turns out to be a problem of distributing the burden of paying for excessive, unwanted public works. Water itself is a free good in the Basin. Actual distribution of the repayment burden is partly ideological and partly pragmatic; partly a political choice and partly a bureaucratic decision; partly a manifestation of agrarian policy and partly what the traffic will bear. If water is free, it is not an economic good, and not a subject for economic analysis . The Basin has an ample water supply, but water may nevertheless be locally and periodically scarce. The water problem is therefore one of conveyance and timing. Control of timing requires storage. Conveyance requires energy, as well as aqueducts. In the Weber Basin, conveyance energy may be either the controlled flow of falling (mountain) water, or electrically powered pumps tapping abundant groundwater reservoirs. The water development problem is, therefore, an issue of alternative capital facilities for the control and delivery of water (itself abundant). Efficient resource allocation in water development is consequently relevant at the !.!!vestment level; it is not a matter of pricing water. In this case, the major investment decisions have already been implemented, and the problem is one of evaluating distribution of the repayment burden. The relevant economics literature is principles of equitable taxation, and of public utilities' pricing. Application to the Basin situation produces a conclusion that present arrangements are as equitable as could be devised. Further redundant investment (inefficient use of resources), however, could be avoided if the State Engineer's Office took a harder line on requests to drill new wells. The information provided in this work could be the basis for making such a program popularly acceptable.