Predicting the frequency and aerial extent of flooding in river valleys is essential for infrastructure design, environmental management, and risk assessment. Such flooding occurs when the discharge of water within a river channel exceeds its maximum capacity and the extra water submerges the adjoining floodplain surface. The maximum capacity of a channel is controlled by its geometry, gradient, and frictional resistance. Conventional flood prediction methods rely on assumptions of unchanging flood probabilities and channel capacities. However, changes in climate, land cover, and water management have been shown to systematically shift the magnitude and variability of flood flows in many systems. Additionally, alluvial river channels continually adjust their geometries according to characteristics of flow and sediment regimes. For example, channels can expand their geometry during high-energy flows through erosion, then contract their geometry through sediment deposition during low-energy flows. This means that changes in flow magnitudes, frequencies, or durations can cause changes in a channel’s maximum capacity due to adjustments in river channel geometry. Therefore, future changes in river flow regimes and channel geometry may amplify or attenuate the frequency and magnitude of flood inundation in unexpected ways. The focus of this thesis is the development of a novel simulation model to investigate potential changes in the frequency and aerial extent of floodplain inundation due to systematic changes in peak flows and subsequent adjustments in channel geometry and capacity. The model was run using six hypothetical flow scenarios to explore how changes in the mean and variance of an annual peak flow series influences the frequency and magnitude of floodplain inundation. In order to qualitatively simulate the various mechanisms controlling channel adjustment across a continuum of different river environments, each scenario was run multiple times while gradually varying model parameters controlling the amount of permissible adjustment in channel geometry. Results suggest that systematic shifts in peak flows cannot be translated directly to changes in the frequency or magnitude of floodplain inundation due to the non-linear factors controlling the rate and trajectory of channel adjustment. Insights gained from these results demonstrate the need to account for potential changes in both peak flows and channel capacities in the prediction and mitigation of flood hazards.

The willingness to pay of participants in cisco fishing was studied for 1970. Opportunity cost of time, calculated from foregone income, was examined as part of the total costs of fishing. The opportunity cost of time was found to be a significant factor in the consumers' decision to participate, and therefore effected the valuation of the recreation considerably. Additionally, the coefficients of income and opportunity costs of time were compared and found to be of different sign for rural counties indicating a difference between the two variables.

Application was made of the economic rent method of resource valuation for the resident deer hunt in Utah. Total economic, location and quality rent values were estimated for all hunting units. These values incorporate the relationship existing between the variable use cost and the units of activity associated with the site. Data were collected by mail survey from hunters following the 1970 season. Approximately 2033 questionnaires were used in the analysis. Additional data were collected from the Utah Division of Natural Resources. The total rent value estimated from the model was approximately $3,326,238.00. Eighty-five percent of the total was attributed to quality and 15 percent to location. Total rent values were highest for Unit 2 (Cache, Unit l (Box Elder) and Unit 6 (Lost Creek). It was hypothesized that variations in quality value could be explained by variations in site specific factors. The factors were made subject to multiple regression analysis and the number of bucks, two and one-half years of age and greater taken by resident hunters, was found to be the most significant. Variation in this variable and the others in the model explained 71.3 percent of the variation in the site quality value. To test the sensitivity of capacity in the model, an additional set of capacity constraints were estimated and used in the least-cost program. This gave a higher least cost allocation as the hunters were forced to incur a higher transfer cost. In this allocation the location value increased as the quality value decreased. Multiple regression analysis indicated that 83.3 percent of the variation in site quality was due to variations in site specific factors.

The objective of this thesis is to update the Mori-Butterworth (2006) model of the krill-predator dynamics of the Antarctic ecosystem. Their analysis aimed to determine whether predator-prey interactions alone could broadly explain the observed population trends of the species considered in their model. In this thesis, the Antarctic ecosystem is outlined brie y and details are given of the main krill-eating predators including whales, seals, fish and penguins, together with an historical record of the human harvesting in the region. The abundances and per capita krill consumption of the krill-predators are calculated and used to determine the main krill-predators to be used in the updated model developed. These predators are found to be the blue, fin, humpback and minke whales and crabeater and Antarctic fur seals. The three main ship surveys (IDCR/SOWER, JARPA and JSV) used to estimate whale abundance, and the abundance estimation method itself (called distance sampling), are summarised. Updated estimates of abundance and trends are listed for the main krill-predators. Updated estimates for the biological parameters needed for the ecosystem model are also reported, and include some differences in approaches to those adopted for the Mori-Butterworth model. The background to the hypothesis of a krill-surplus during the mid-20th century is discussed as well as the effects of environmental change in the context of possible causes of the population changes of the main krill-feeding predators over the last century. Key features of the results of the updated model are the inclusion of a depensatory effect for Antarctic fur seals in the krill and predator dynamics, and the imposition of bounds on Ka (the carrying capacity of krill in Region a, in the absence of its predators); these lead to a better fit overall. A particular difference in results compared to those from the Mori-Butterworth model is more oscillatory behaviour in the trajectories for krill and some of its main predators. This likely results from the different approach to modelling natural mortality for krill and warrants further investigation. That may in turn resolve a key mismatch in the model which predicts minke oscillations in the Indo-Pacific region to be out of phase with results from a SCAA assessment of these whales. A number of other areas for suggested future research are listed. The updated model presented in this thesis requires further development before it might be considered sufficiently reliable for providing advice for the regulation and implementation of suitable conservation and harvesting strategies in the Antarctic.

Due to increased adoption of irrigation and advancements in technology, producers in the Mississippi Delta have been unsustainably depleting the water stocks in the Mississippi River Valley Alluvial Aquifer (MRVAA). This research investigates the impacts of various regulatory threats uniformly applied to heterogeneously located producers to avert further overexploitation of the MRVAA. If a regulatory threat successfully incentivizes reduction of producers’ extraction rates, costly implementation of a binding limited-use regulation could be avoided. Laboratory experiments incorporating the major characteristics of the MRVAA were conducted to test two threatened uniform policies, limited-use and moratorium. The main finding of the research is that even with the threat of a moratorium, the regulatory trigger point was too lax to result in significantly slowing over exploitation of the water resource.

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