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.

Philosophiae Doctor - PhD / The need for a fundamental change in our approach to water management in South Africa is largely underpinned by the country's Constitution (Act 108 of 1996). Section 24 in Chapter 2 of the Constitution is perhaps the most relevant to be considered when developing a groundwater source and aquifer protection zoning policy, as it explicitly endorses the right to have the environment protected. The mandate required to give effect to the overall protection of South Africa's water resources spans across several sectors and government departments, with expected roles and responsibilities not always clearly defined. The Department of Water Affairs and Forestry (DWAF) is primarily responsible for water resource management. However, the Department of Environmental Affairs and Tourism (DEAn, the National Department of Agriculture (NDA) and the Department of Provincial and Local Government (DPLG) are all key role-players because of their respective responsibilities for biodiversity conservation, land management and development planning across government.

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.

No description available.

No description available.

No description available.

No description available.

Salt marshes along many tidal systems in New England have been ditched since colonial times. These ditches have been thought to help control mosquito populations and increase salt marsh hay production by improving water drainage from the marsh. Although these ditches are prominent geomorphic features, little quantitative work has focused on how these man-made ditches may alter marsh hydrology and geomorphology. This study attempts to quantify the ways in which ditches alter sediment and water transport pathways and how that affects the overall morphology and surface geology. This study also addresses treatment affects on sedimentation from fertilization and fish removal associated with the NSF funded TIDE project. Short-term sediment deposition rates and relative elevations were determined for ditched and non-ditched marsh areas in four tidal creeks along the Rowley River in the summers of 2003, 2004, 2005, and 2006. Total suspended solids samples were also collected in the creek channels adjacent to the marsh areas sampled. Marsh surface samples for grain size analysis and organic content were collected as well. To quantify flow patterns, a grid system of stakes was set up on the marsh platform of two creek systems and water height was measured relative to these stakes over the course of a tidal cycle. This allowed for a better determination of the areas that flooded first and how long water stayed on the marsh platform in ditched and non-ditched areas. Measurements of marsh platform elevation indicated that the interior regions of ditched areas stand significantly lower than non-ditched areas. In ditched marsh areas, the hydrologic data demonstrated that the interior regions of the marsh were typically flooded first and stayed flooded longer. Non-ditched regions instead were flooded only after the water had topped the creek bank. As a result of these modified flow pathways, classic patterns of sedimentation and of organic matter and grain size distribution occurred less often in ditched marsh areas relative to non-ditched areas. In contrast to non-ditched marsh platforms, ditched platforms commonly had areas of increased deposition, decreased organic matter and increased grain size in innermost marsh areas. Although the absolute magnitude of deposition was similar with or without ditches, deposition in ditched areas was somewhat less responsive to the classic control of hydroperiod. Possible explanations for lower platform elevation in ditched marshes include (i) trapping of suspended sediment in ditches and (ii) enhancement of sediment export associated with the short distance from platform to ditch. The former is consistent with observations of lower concentration in ditches relative to natural creeks, and the latter is consistent with observations of coarser grain size and lower organic content observed on ditched marshes relative to non-ditched marshes. A longer hydroperiod and lower elevation in ditched areas would then be required at equilibrium to enhance net deposition so that accretion could keep up with relative sea level rise. The similar observed magnitudes of deposition in ditched and non-ditched areas supports the conclusion that the lower elevation of ditched platforms is in quasi-equilibrium with the higher elevations of non-ditched areas. Other results of this study include a demonstration of the high (1-2 cm) accuracy of the tide stick method for measuring marsh elevation, the finding that short term source of marsh sediment is primarily internal cycling, and the finding that fertilizing creeks systems and removing fish have no significant effects on short term sediment concentration, sediment delivery, sedimentation, inorganic sediment properties or marsh elevation.

Natural coastal habitats throughout Chesapeake Bay are increasingly threatened with shoreline modification due to population growth and rising rates of development. The replacement of these natural coastlines with hardened structures such as seawalls (bulkheads) and stone revetments (riprap) not only compromises vegetation at the land-water interface, but also can influence several elements of local aquatic food webs. Effects of these alterations have been well-studied with respect to fish assemblages and intertidal communities, particularly in conjunction with larger-scale watershed development, and recently, interest has shifted toward investigation of the effects of shoreline development on subtidal benthic infaunal communities.This study evaluated the direct, local impacts of bulkhead and riprap compared to natural marsh shorelines, as well as the effects of sediment characteristics, predator abundance, and system-specific physical features on benthic infauna in the Patuxent River, Chesapeake Bay. Forty-five sites were divided among three shoreline types and distributed across three main river zones. At each site, a benthic infaunal suction sample (3-mm mesh), push-core sample (500-μm mesh), sediment samples, water-quality measurements, and trawls for predators were taken. Samples were sorted to determine density, diversity, and biomass of infaunal organisms. Data were assessed using an Information-Theoretic approach (AIC analysis) to determine the most influential variables, of those measured, on the infaunal community for two benthic data sets: 3-mm-suctions and 500-μm-cores. Results from these analyses on 3-mm samples suggested that shoreline type was the best predictor of diversity, while wave energy, sediment chlorophyll concentration, sediment type, and predator abundance best predicted density and biomass. Benthic responses within the 500-μm dataset were not strongly affected by shoreline type. Rather, responses were best predicted by sediment chlorophyll, wave energy, sediment type, predator abundance, and sediment organic carbon (TOC) content.Results indicate that, compared to other Bay tributaries, the Patuxent River is a relatively degraded system. The small range in long-term responses of Patuxent infauna from previous work provides a possible explanation as to why I was unable to see significant differences in infaunal response among shoreline types in the current study (i.e., there was little scope for change by shoreline in the system as a whole). However, I suggest that natural marsh habitats are healthier subsystems of the Patuxent River, due to the greater variety of infaunal feeding guilds and higher infaunal biomass observed at these compared to hardened sites. Higher predator abundance was associated with higher infaunal biomass at natural marsh sites in both size fractions, suggesting the bottom-up control of higher-trophic-level species in this system, as predators seek out suitable prey items. Given these observations, and the fact that influential variables such as wave energy, sediment nutrient and chlorophyll content, predator abundance, and sediment type may vary according to shoreline type, the replacement of natural shoreline with hardened structures will lead to complex changes in subtidal benthic communities in Chesapeake Bay tributaries and should be minimized to maintain qualities of the natural system.