<p> There is an undisputed need to increase accuracy of snow cover estimation in regions comprised of complex terrain, especially in areas dependent on winter snow accumulation for a substantial portion of their annual water supply, such as the Western United States, Central Asia, and the Andes. Presently, the most pertinent monitoring and research needs related to alpine snow cover area (SCA) are: (1) to improve SCA monitoring by providing detailed fractional snow cover (FSC) products which perform well in temporal/spatial heterogeneous forested and/or alpine terrains; and (2) to provide accurate measurements of FSC at the watershed scale for use in snow water equivalent (SWE) estimation for regional water management. </p><p> To address the above, the presented research approach is based on Landsat Fractional Snow Cover (Landsat-FSC), as a measure of the temporal/spatial distribution of alpine SCA. A fusion methodology between remotely sensed multispectral input data from Landsat TM/ETM+, terrain information, and IKONOS are utilized at their highest respective spatial resolutions. Artificial Neural Networks (ANNs) are used to capture the multi-scale information content of the input data compositions by means of the ANN training process, followed by the ANN extracting FSC from all available information in the Landsat and terrain input data compositions. The ANN Landsat-FSC algorithm is validated (RMSE ~ 0.09; mean error ~ 0.001-0.01 FSC) in watersheds characterized by diverse environmental factors such as: terrain, slope, exposition, vegetation cover, and wide-ranging snow cover conditions. ANN input data selections are evaluated to determine the nominal data information requirements for FSC estimation. Snow/non-snow multispectral and terrain input data are found to have an important and multi-faced impact on FSC estimation. Constraining the ANN to linear modeling, as opposed to allowing unconstrained function shapes, results in a weak FSC estimation performance and therefore provides evidence of non-linear bio-geophysical and remote sensing interactions and phenomena in complex mountain terrains. The research results are presented for rugged areas located in the San Juan Mountains of Colorado, and the hilly regions of Black Hills of Wyoming, USA. </p>

<p> In this paper, we study solute transport in an individual fracture and the surrounding porous rock. Specifically, we consider a parallel-plate model of a single fracture that allows for the diffusion of solute within the matrix and the adsorption of solute to the fracture walls. We developed two stochastic particle-tracking methods to numerically solve for the concentration of the fracture model. The first is the hi-res method which captures the solute dynamics at a micro-scale. The second algorithm we develop, the upscaled method, captures the large-scale dynamics of the system at vastly reduced computational cost. We verified the accuracy of these methods by comparing their results to numerical results from the literature. We also compared the efficiency of the developed particle tracking methods to an existing particle tracking method from the literature in the case of no interface absorption.</p>

<p> The hydrogeologic controls, flow velocities and paths, groundwater delineation, and physical characteristics in a joint controlled dendritic conduit-spring system have been characterized. The known conduit branches from C My Shovel (CM) Cave with 4475 meters (m) of measurable passages and tributaries. Surface entrance to CM Cave is located 1360 m upstream from discharge at Magic Springs. </p><p> Four storm events were measured characterizing the dynamics. The maximum discharge of these four events was 1.2 m³/s (41 ft³/s) with 0.08 m³/s (3 ft³/s) baseflow conditions at Magic Springs. The characteristic shape and response of discharge are well defined with a rise time between 5.5 and 6.5 hours (hr). The half flow period time (t_0.5) ranges between 12.9 and 15.7 hr, depending on peak discharge. The rise time and t0.5 occur in less than one day and the conduit volume exceeds 0.5 x 10⁶ m³. The conduit-spring system drains within 3.7 to 7.5 days after the storm event. The thermal effects are event driven, maintaining 85% of the temperature change over 1300 m. The spring discharge has total dissolved solids around 350 mg/L and is chemically stable. </p><p> The field component of this study include a karst density survey, four dye traces, and continuous monitoring of specific conductance, pressure, temperature, water-level stage height, and discharge at Magic Springs and in the conduit below CM Cave. The general karst density survey identifies caves and dolines within given area. There is a sinking stream that transfers flow from Spring Branch Creek into the conduit system and two focused regions in a karst plain having densities of 20 and 44 karst features/0.16 km². </p><p> Hydrographs and chemographs show patterns interpreted as pulses of dilute water recharging through exposed caves, sinkholes, and sinking streams. These pulses have minimal reaction with the rock or matrix during recharge, which is superimposed on baseflow from the joint controlled dendritic conduit-spring system in this karst terrane. </p><p> The groundwater drainage basin has been defined. The dye tracing results identified groundwater piracy across surface water divides and helped define the groundwater drainage basin. Groundwater velocities were measured between 1800 m/d and 3000 m/d under baseflow conditions. The discharge at Magic Springs under these four storm events showed velocities between 8,700 and 15,120 m/d. </p><p> An autosampler and charcoal packets were both employed during dye tracing. Both detected fluorescence from all four injection sites. The measured velocities ranged between 1865 up to 2929 m/d under baseflow conditions. All dye trace tests were conducted under baseflow. Under baseflow conditions, dye was only traced to the Magic Springs locations from the eleven charcoal monitoring locations.</p>

<p> This thesis examines the significance of a micro-level approach to the Israeli-Palestinian water conflict. By rethinking scale of analysis and examining local insecurities, Palestinian experiences reveal how water conflict plays out in latent and discursive ways. In a step-by-step method, I detail the processes and outcomes of the water struggle in the West Bank. First, I show how technical challenges ((i) poor water supply, (ii) antiquated water infrastructure, (iii) failed institutions) are shaped by political imperatives. Second, I show how Palestinians have responded to local water sector challenges: (iv) nonpayment to the Palestinian Water Authority for their water supply, (v) increasing rural to urban migration by Palestinian farmers. As a result, Palestinian society is stuck in cycles of crisis that make the conditions increasingly ungovernable. While Palestinians are stuck in a mode of ungovernability, their position in the peace process with Israel is undermined.</p>

<p> The Runoff Risk Advisory Forecast (RRAF) provides Wisconsin's farmers with an innovative decision support tool which communicates the threat of undesirable conditions for manure and nutrient spreading for up to 10 days in advance. The RRAF is a pioneering example of applying the National Weather Service's hydrologic forecasting abilities towards the Nation's water quality challenges. Relying on the North Central River Forecast Center's (NCRFC) operational Snow17 and Sacramento Soil Moisture Accounting Models, runoff risk is predicted for 216 modeled watersheds in Wisconsin. The RRAF is the first-of-its-kind real-time forecast tool to incorporate 5-days of future precipitation as well as 10-days of forecast temperatures to generate runoff risk guidance. The forecast product is updated three times daily and hosted on the Wisconsin Department of Agriculture, Trade, and Consumer Protection (DATCP) website. Developed with inter-agency collaboration, the RRAF model was validated against both edge-of-field observed runoff as well as small USGS gauged basin response. This analysis indicated promising results with a Bias Score of 0.93 and a False Alarm Ratio (FAR) of only 0.34 after applying a threshold method. Although the threshold process did dampen the Probability of Detection (POD) from 0.71 to 0.53, it was found that the magnitude of the events categorized as hits was 10-times larger than those classified as misses. The encouraging results from this first generation tool are aiding State of Wisconsin officials in increasing awareness of risky runoff conditions to help minimize contaminated agriculture runoff from entering the State's water bodies.</p>

<p> Ordered mesoporous carbon (OMC) materials have attracted great interests from NASA due to their remarkable properties, such as high specific surface area, regular and tunable pore size. These features show great potential for being used in the water recovery system (WRS) in the International Space Station (ISS) as potential adsorbents. Various methods have been explored on the OMC preparation and modification to achieve better adsorption results. In this research, acrylic acid was used as a carbon precursor to synthesize OMC using a common silica mesoporous template (SBA-15). The influence of silica template amount was tested by using different ratios of SBA-15 to acrylic acid. The modification processes were conducted by immersing methods using four different aqueous solutions: 30% ammonium hydroxide, 0.1% sodium hydroxide, 1 mol/L aluminum chloride, and 0.02 g/mL urea solution. BET-SSA, FT-IR, TEM, TGA, and XRD were used to characterize the structures of OMCs and modified OMCs. It demonstrated that all the products had well-ordered hexagonal structure. The modifying procedures had eroded the surface of the OMC, but the highly ordered structures had been preserved based on the TEM and XRD results. FT-IR analysis indicated that the functional groups were introduced to the surface of the modified OMCs, which affected the adsorption capacity significantly. Resorcinol, a typical total organic carbon (TOC) model compound, was selected to evaluate the adsorption behavior of the OMCs and modified OMCs. Adsorption study illustrates that OMC produced by 3:1 ratio of SBA-15 to acrylic acid showed a higher adsorption capacity than that of OMCs produced with other ratios. The ammonium hydroxide modified OMC had the highest adsorption capacity of 40.6 mg/g for resorcinol removal, compared with that of the other three modified OMCs.</p>

<p> Forecasts of hydrological information are vital for many of society's functions. Availability of water is a requirement for any civilization, and this necessitates quantitative estimates of water for effective resource management. The research in this dissertation will focus on the forecasting of hydrological quantities, with emphasis on times of anomalously low water availability, commonly referred to as droughts. Of particular focus is the quantification of uncertainty in hydrological forecasts, and the factors that affect that uncertainty. With this focus, Bayesian methods, including ensemble data assimilation and multi-model combinations, are utilized to develop a probabilistic forecasting system. This system is applied to the upper Colorado River Basin for water supply and drought forecast analysis. </p><p> This dissertation examines further advancements related to the identification of drought intensity. Due to the reliance of drought forecasting on measures of the magnitude of a drought event, it is imperative that these measures be highly accurate. In order to quantify drought intensity, hydrologists typically use statistical indices, which place observed hydrological deficiencies within the context of historical climate. Although such indices are a convenient framework for understanding the intensity of a drought event, they have obstacles related to non-stationary climate, and non-uniformly distributed input variables. This dissertation discusses these shortcomings, demonstrates some errors that conventional indices may lead to, and then proposes a movement towards physically-based indices to overcome these issues. </p><p> A final advancement in this dissertation is an examination of the sensitivity of hydrological forecasts to initial conditions. Although this has been performed in many recent studies, the experiment here takes a more detailed approach. Rather than determining the lead time at which meteorological forcing becomes dominant with respect to initial conditions, this study quantifies the lead time at which the forecast becomes entirely insensitive to initial conditions, and estimating the rate at which the forecast loses sensitivity to initial conditions. A primary goal with this study is to examine the recovery of drought, which is related to the loss of sensitivity to below average initial moisture conditions over time. Through this analysis, it is found that forecasts are sensitive to initial conditions at greater lead times than previously thought, which has repercussions for development of forecast systems.</p>

<p> This study used a mass balance approach by characterizing the input, output, and sink rates of N in order to assess a declared "stage III N-saturated forest" response to decreased atmospheric N deposition in western Maryland. Relying on the conceptual model of kinetic N-saturation to holistically link stream, vegetative, soil, and atmospheric compartments and the use of a novel stable isotopic technique, the study demonstrated dynamic soil NO₃-N pools, unprocessed atmospheric NO₃-N in base flow, and significant reductions in NO₃-N yield in response to decreased atmospheric N deposition. A lumped conceptual model, incorporating a dormant season NO₃-N flush, was proposed that explains forest response to decreased deposition and sheds light on the hydrologic processes that govern the storage/release of NO₃-N among years. It is proposed that this flushing mechanism prevents forests from attaining higher stages of N-saturation and predicts forests will be responsive to further reductions in N deposition. </p>

<p> This study investigated two important aspects of hydrologic effects of low impact development (LID) practices at the watershed scale by (1) examining the potential benefits of scaling up of LID design, and (2) evaluating downstream effects of LID design and its spatial translation within a watershed. The Personal Computer Storm Water Management Model (PCSWMM) was used to model runoff reduction with the implementation of LID practices in Deer Creek watershed (DCW), Missouri. The model was calibrated from 2003 to 2007 (R² = 0.58 and NSE = 0.57), and validated from 2008 to 2012 (R² = 0.64 and NSE = 0.65) for daily direct runoff. Runoff simulated for the study period, 2003 to 2012 (NSE = 0.61; R² = 0.63), was used as the baseline for comparison to LID scenarios. Using 1958 areal imagery to assign land cover, a predevelopment scenario was constructed and simulated to assess LID scenarios' ability to restore predevelopment hydrologic conditions. The baseline and all LID scenarios were simulated using 2006 National Land Cover Dataset.</p><p> The watershed was divided in 117 subcatchments, which were clustered in six groups of approximately equal areas and two scaling concepts consisting of incremental scaling and spatial scaling were modelled. Incremental scaling was investigated using three LID practices (rain barrel, porous pavement, and rain garden). Each LID practice was simulated at four implementation levels (25%, 50%, 75%, and 100%) in all subcatchments for the study period (2003 to 2012). Results showed an increased runoff reduction, ranging from 3% to 31%, with increased implementation level. Spatial scaling was investigated by increasing the spatial extent of LID practices using the subcatchment groups and all three LID practices (combined) implemented at 50% level. Results indicated that as the spatial extent of LID practices increased the runoff reduction at the outlet also increased, ranging from 3% to 19%. Spatial variability of LID implementation was examined by normalizing LID treated area to impervious area for each subcatchment group. The normalized LID implementation levels for each group revealed a reduction in runoff at the outlet of the watershed, ranging from 0.6% to 3.7%. This study showed that over a long-term period LID practices could restore pre-development hydrologic conditions. The optimal location for LID practice implementation within the study area was found to be near the outlet; however, these results cannot be generalized for all watersheds. </p>

<p> Releases of perchloroethylene (PCE) from dry cleaners pose a threat to groundwater quality. An assessment was performed of the Niles Cone Groundwater Basin to determine its vulnerability to PCE contamination from both historic and more recently operating dry cleaners. Sensitivity assessments of the Basin's two subbasins were performed using a modification of the DRASTIC Index Method, whereby the hydrogeological variables of depth to water, aquifer media, vadose zone media, and soil drainage classification were represented by a range of sensitivity categories and ratings assigned to each range. A source assessment was performed by identifying the locations of historic and presently operating dry-cleaning plants and assigning a threat ranking to each based on the approximate years in which the four generations of dry-cleaning machinery were introduced. Using ArcGIS, the sensitivity assessments and the source assessment were mapped, and the source assessment was superimposed over the sensitivity maps to create vulnerability maps of the two subbasins. The most sensitive area of the Below Hayward Fault subbasin in the forebay area near the Hayward Fault is due to a higher proportion of coarse-grained aquifer and vadose zone media and a thinner to absent aquitard due to deposition from the Alameda Creek. The existence of dry cleaners of higher threat makes this an area that is vulnerable to PCE contamination.</p>