As landscapes become increasingly urbanized, there is an associated increase in impervious cover. Impervious surfaces, such as roads, rooftops, and parking lots contribute to the physical, hydrological, chemical, and biological alteration of stream systems. Biotic assemblages consistently degrade with increased watershed impervious cover; however, at low levels of impervious cover, these assemblages exhibit wide variability in biotic integrity. This study investigated which reach- and watershed-scale factors explained biotic condition (i.e., richness, flow traits, thermal traits, and tolerance for macroinvertebrates and fishes) at similar levels of low imperviousness. The primary objective was to identify factors that confer resistance for biota, such that they retain high biotic integrity at low levels of impervious cover, and, conversely, to determine which factors make biota more vulnerable to urban disturbance, such that they have low biotic integrity despite low levels of impervious cover. Forty sites were selected across Massachusetts within two narrow bands of impervious cover: 1–4% (n = 20) and 7–10% (n = 20). Models with reach-scale variables (reflecting habitat heterogeneity, flow, temperature, or water quality) or watershed-scale variables (representing natural characteristics, land use, flow alterations, and other measures of urbanization or impervious) explained additional variance compared to models with impervious cover alone. Reach-scale factors tended to explain more variance than watershed-scale factors for all biotic responses except fluvial fishes, with overall more variance explained for fish than macroinvertebrate assemblages. At the reach scale, colder water temperatures, higher dissolved oxygen, and more large wood were related to higher proportions of fluvial, coldwater, and intolerant fishes. For macroinvertebrates, warmer water temperature, smaller sediment size, and higher nitrate were related to higher macroinvertebrate richness and tolerance. At the watershed scale, air temperature emerged as an important predictor for both taxonomic groups and across response metrics; air temperature was highly correlated with high-elevation watersheds. Other important watershed-scale predictors were open water and dams, flow alteration, and other urban measures such as housing density, impervious in a 120-m buffer, and road crossings. Restoration should focus on strategies to reduce impacts that would degrade in-stream conditions that allow for higher biotic integrity, such as habitat heterogeneity, more large wood, and colder water temperatures. Similarly, watersheds should be prioritized for protection with those characteristics potentially more resistant to urban disturbance, such as high-elevation regions that retained high biotic integrity despite higher dam density, more road crossings, and more flow alteration.

Problems with storm water runoff are becoming more frequent, and the main cause is the increase of impervious cover (IC). The imperviousness increases stream peak flows, changes peak times, and so changes the flood distribution. Several policies are used to manage flows and flooding; however most have been reported to be inefficient because land owners do not have correct exposure to price incentives and risk. The main contributions of this thesis are an investigation into market mechanisms to price and allocate impervious cover allowances, while managing flood distribution. The market mechanisms are based on the electricity and gas markets which use linear programming formulations. This thesis develops three net pool market mechanisms: Det_MarketIC is a capped and deterministic market for IC, and Sto_MarketIC and Sto_MarketIC_Risk are stochastic market models with flood component penalties and risk positions representing the desired risk from the community respectively. Additionally, a gross pool market was extended under rainfall uncertainty, Gross_MarketIC. The market design is an auction system with operational constraints and bids for IC allowances from participants. The system relates physical routed flows at nodal or control points to these bids. The models clear the market by creating a demand (supply) curve for increments (reductions) in flows at specific places, and accounts for marginal changes in the expected flood damage and flood damage components. The market formulations estimate efficient allocations and prices. Decomposed prices from the market models are shown based on duality, as applied in electricity markets. The dual prices show spatial and temporal effects of flows, which impact at flooding areas. With Sto_MarketIC and Gross_MarketIC, prices account for changes in flood distribution. With Sto_MarketIC_Risk, prices also account for the risk as CVaR in flooding areas. Thus, prices increase as binding risk conditions are tightened. Finally, the net pool models are illustrated using hydrological and hydraulic simulators based on a small catchment located in Canterbury, New Zealand. Allocations and prices varied with the different models. Participants would face increasing prices in their IC allowances due to increments in flood damage.

There is currently a great need to expand the understanding of land use policy’s impact on water quality. The purpose of this thesis is to examine local policy in place in Covington, Louisiana in order to find out if it is having an impact on land use, which then has an impact on water quality. Methods used included reclassification of land use categories within a Geographical Information System and analysis of changes in the city over a four year period. Policy was assessed using a pre-existing evaluation method from The Center for Watershed Protection as well as by a more flexible instrument developed by staff and faculty in the Department of Landscape Architecture at Mississippi State University. Three water quality parameters were examined for impairment due to their known correlation to urban runoff. It was determined that Covington’s water quality related policy is insufficient and is having little effect to curtail the types of development occurring within its boundaries. Impervious cover within the city is rising and surface waters both within and around the city are impaired.

Thesis (M.T.S.C.)--Miami University, Dept. of English, 2005. / Title from first page of PDF document. Document formatted into pages; contains [1], vi, 64, [2] p. : ill. Includes bibliographical references (p. 32).

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