Aogu Farm was built on reclaimed land. Because of its rich ecological resources, Aogu was defined as a "Major Wildlife Habitat" in Chiayi County by the Forest Service and is also expected to reduce carbon in the plan for the flatland forest. Power pumps are currently used to irrigate and cultivate the area. However, after becoming the Forest Recreation Area in the future, Aogu Farm has to reduce the influence of human beings. However, if the Taisugar Company doesn¡¦t support the plan of Forest Service or abandons farming and stops the pumping power, the Aogu Wetlands will suffer the crisis of coastal inundation. Hydrological models have their own characteristics. For example, inundation models for regional drainage using one-dimensional channel flow, two-dimensional overland flow, and runoff in the mountains all can be assessed to solve the inundation problems in the coastal lowlands. Nevertheless, the Aogu Wetlands, the Case Study area, has both a dry season and a wet season even in the lowland. When rainstorms occur, the area is unable to discharge the water by gravity but can depend only on pumps to discharge the water into the sea. Therefore, based on the need to manage water, hydrological surveys must be conducted to assess the hydrological impact of continuous rainfall on the Aogu Wetlands and to provide reference information to assist in the management. In the thesis, I use both the Geographic Information System (GIS) and the Storm Water Management Model (SWMM) as analysis tools. Moreover, the different regions are further divided into watershed and the route of drainage, establishing two kinds of models of watershed hydrology for precipitation simulations. Finally, to compare these two methods, the Arc Hydro and SWMM models are used in watershed analysis.

This thesis presents an investigation of ensemble Gaussianity, the effect of non- Gaussianity on covariance structures, storm-centered data assimilation techniques, and the relationship between commonly used data assimilation variables and the underlying dynamics for the case of Hurricane Humberto. Using an Ensemble Kalman Filter (EnKF), a comparison of data assimilation results in Storm-centered and Eulerian coordinate systems is made. In addition, the extent of the non-Gaussianity of the model ensemble is investigated and quantified. The effect of this non-Gaussianity on covariance structures, which play an integral role in the EnKF data assimilation scheme, is then explored. Finally, the correlation structures calculated from a Weather Research Forecast (WRF) ensemble forecast of several state variables are investigated in order to better understand the dynamics of this rapidly intensifying cyclone. Hurricane Humberto rapidly intensified in the northwestern Gulf of Mexico from a tropical disturbance to a strong category one hurricane with 90 mph winds in 24 hours. Numerical models did not capture the intensification of Humberto well. This could be due in large part to initial condition error, which can be addressed by data assimilation schemes. Because the EnKF scheme is a linear theory developed on the assumption of the normality of the ensemble distribution, non-Gaussianity in the ensemble distribution used could affect the EnKF update. It is shown that multiple state variables do indeed show significant non-Gaussianity through an inspection of statistical moments. In addition, storm-centered data assimilation schemes present an alternative to traditional Eulerian schemes by emphasizing the centrality of the cyclone to the assimilation window. This allows for an update that is most effective in the vicinity of the storm center, which is of most concern in mesoscale events such as Humberto. Finally, the effect of non-Gaussian distributions on covariance structures is examined through data transformations of normal distributions. Various standard transformations of two Gaussian distributions are made. Skewness, kurtosis, and correlation between the two distributions are taken before and after the transformations. It can be seen that there is a relationship between a change in skewness and kurtosis and the correlation between the distributions. These effects are then taken into consideration as the dynamics contributing to the rapid intensification of Humberto are explored through correlation structures.

Land development transforms the natural landscape and impacts in stream ecosystems and downstream communities as it alters the natural flow regime. An increase in impervious areas results in higher volumes of storm water runoff, reduced time to peak, and more frequent flooding. Best Management Practices (BMP) and Low Impact development (LID) are a few of the set of measures which are used to mitigate the impact of urbanization. Peak flow, runoff volume are few of the conventional metrics which are used to evaluate the impact and performance of these storm water management strategies on the watershed. BMP are majorly used to control the flood runoff but results in the release of large volumes of runoff even after the flood wave passed the reach and LIDs are used to replicate the natural flow regime by controlling the runoff at the source. Therefore need to incorporate a metric which includes the timing and area being inundated needs to be considered to study the impact of these strategies on the downstream. My proposed research will focus on simulating the Low Impact Development (LID) techniques like permeable pavements and rainwater harvesting on an urbanized watershed using a curve number approach to quantify the hydrologic performance of these strategies on the watershed. LID, BMPs, and combined strategies are introduced for retrofitting existing conditions and their hydrologic performance is accessed based on the peak flow and a new metric Hydrologic Footprint Residence. A simulation optimization framework would be developed which identifies cost effective LID options that maximize the reduction of peak flow from the existing condition design storms while meeting budget restrictions. Further LID and BMP placement is included in the optimization model to study the impact of the combined scenario on the storm water management plans and their performance based on different storms and corresponding budget. Therefore a tradeoff can be illustrated between the implementation cost and the hydrological impact on the watershed based on the storm water management approach of using only LID and combination of LID and BMP corresponding to varied spectrum of design storm events.

The alongshore variability of beach-dune systems and the response and recovery from extreme storms remains poorly understood. The height and extent of foredunes along barrier islands varies over a range of spatial scales, implying that during extreme storms, the beach-dune system should respond in different ways depending on the elevation and volume of the dunes relative to the storm surge. The purpose of this study is to use Ground-Penetrating Radar (GPR) and vibra-cores to investigate the internal structure of small, intermediate and large dunes along a 2.5 km transect of beach in Padre Island National Seashore, TX with particular attention to storm impacts. A series of dune normal and parallel GPR profiles were collected to capture the variation in beach-dune morphology at the three sites. Site locations were chosen along a transition from dissipative to intermediate beach states. Following the Sallenger (2000) storm impact model, the small dune is defined by low-lying topography that is susceptible to overwash and inundation depending on the size of the storm surge. The large dune is characteristic of the “collision regime”, while the intermediate dune represents a transition between “overwash” and “collision regimes”, with the underlying assumption that all three dunes would be impacted by the same level of surge during a single storm event. Results from the GPR survey suggest that each site contains a bright, laterally continuous radar reflector that is interpreted with the aid of the sedimentary data as an erosional layer. Different characteristic radar facies and sequence boundaries provide evidence as to how each dune evolved through and after the storm. Results from XRF scans and grain size analysis show a direct comparison between the GPR reflectors at the storm surface and spikes in calcium counts from XRF scans to distinct changes in grain size parameters at the same depth. It is argued that the location of each shell layer corresponds to a storm surface generated during a single storm, which means it is possible to interpret different recovery mechanisms. The presence of the storm layer across the backbeach and dunes provides evidence for the height and extent of the surge during the storm event. The data suggests that the small dune was overtopped by the surge, experiencing minimal erosion and recovery. The intermediate dune was completely eroded by the surge, but showed the greatest recovery of all the dune sites. The large dune was scoured at the base with marginal impact along its crest and shows minimal recovery after the storm. These results suggest that the evolution (i.e., transgression) of a barrier island varies considerably over short distances.

This thesis contains an observational analysis of the genesis of Tropical Storm Allison (2001). Using a paradigm of tropical cyclone formation as the superposition of potential vorticity (PV) anomalies, the importance of different scales of PV merger to various aspects of Allison’s formation is discussed. While only the case of Allison is discussed in great detail, other studies have also documented PV superposition on various scales, and superposition could be important for most tropical cyclones. Preceding Allison’s genesis, PV superposition on the large scale destabilized the atmosphere and increased low-level cyclonic vorticity. This presented a more favorable environment for the formation of MCV-type PV anomalies and smaller, surface-based, meso-β-scale vortices. Although these vortices eventually merged to form a more concentrated vortex with stronger surface pressure gradients, the merger happened well after landfall of Allison and no strengthening ensued. The unstable, vorticity-rich environment was also favorable for the development of even smaller, meso-γ-scale vortices that accompanied deep convective cells within one of Allison’s meso-β-scale vortices. The observations herein suggest that the meso-γ- scale convective cells and vortices are the respective source of PV production and building blocks for the meso-β-scale vortices. Finally, this thesis discusses issues related to the multiple vortex nature of tropical cyclone formation. For instance, the tracking of developing tropical cyclones is greatly complicated by the presence of multiple vortices. For these cases, the paradigm of a single cyclone center is inappropriate and alternative tracking methods are introduced.

Stormwater pollutants originating from industrial facilities can lead to degraded water quality, even in residentially dominated regions of the country. The National Pollutant Discharge Elimination System permit program regulates stormwater pollutants generated at industrial sites using Multi-Sector General Permits (Generic permits) for industrial facilities and a permit requirement for Municipal Separate Storm Sewer System (MS4) operators. All industrial facilities within 11 broad categories of industry are responsible for self-identifying the need to comply with the Generic permit, and subsequently, implementing self-selected pollution prevention strategies. MS4 operators are required to identify and inspect high risk industrial and commercial facilities that may be contributing substantial pollutant loads to the MS4, in addition to other requirements. This is partially in recognition that compliance with the Generic permit has been poor. This dual level of regulations is designed to enhance water quality protection, however, the reliance on local inspectors to develop a definition of high risk has led to irregular implementation. This research developed a methodology to identify industrial facilities and then screen out facilities that may not require inspection by the MS4 operator. Phone questionnaires were administered to 250 industrial facilities. Results were validated using fenceline visits and on-site inspections with local inspectors. Overall compliance by participating facilities with the Generic permit was approximately 10%. Neither the Generic permit nor the MS4 permit has been effective because numerous facilities have gone unregulated. Currently, the Generic permit has attempted to regulate too many facilities, many of which may not be affecting water quality. MS4 high risk inspections have not improved compliance with Generic permit either because of the prioritization of facilities. The reliance on local interpretation, which requires MS4 operators to select a definition of high risk based on their desired level of water quality protection and available resources, can potentially exclude many facilities from inspection. Adopting a definition of intensity for regulating industry may both improve compliance with the General permit, ensure water quality protection, and improve resource usage.

Stormwater pollutants originating from industrial facilities can lead to degraded water quality, even in residentially dominated regions of the country. The National Pollutant Discharge Elimination System permit program regulates stormwater pollutants generated at industrial sites using Multi-Sector General Permits (Generic permits) for industrial facilities and a permit requirement for Municipal Separate Storm Sewer System (MS4) operators. All industrial facilities within 11 broad categories of industry are responsible for self-identifying the need to comply with the Generic permit, and subsequently, implementing self-selected pollution prevention strategies. MS4 operators are required to identify and inspect “high risk” industrial and commercial facilities that may be contributing substantial pollutant loads to the MS4, in addition to other requirements. This is partially in recognition that compliance with the Generic permit has been poor. This dual level of regulations is designed to enhance water quality protection, however, the reliance on local inspectors to develop a definition of “high risk” has led to irregular implementation. This research developed a methodology to identify industrial facilities and then screen out facilities that may not require inspection by the MS4 operator. Phone questionnaires were administered to 250 industrial facilities. Results were validated using fenceline visits and on-site inspections with local inspectors. Overall compliance by participating facilities with the Generic permit was approximately 10%. Neither the Generic permit nor the MS4 permit has been effective because numerous facilities have gone unregulated. Currently, the Generic permit has attempted to regulate too many facilities, many of which may not be affecting water quality. MS4 “high risk” inspections have not improved compliance with Generic permit either because of the prioritization of facilities. The reliance on local interpretation, which requires MS4 operators to select a definition of “high risk” based on their desired level of water quality protection and available resources, can potentially exclude many facilities from inspection. Adopting a definition of intensity for regulating industry may both improve compliance with the General permit, ensure water quality protection, and improve resource usage.

Tropical Storm Debby affected the Gulf coast of Florida in late June, 2012. The storm's southerly approach temporarily reversed the annual net southward longshore sediment transport. The energetic conditions associated with Tropical Storm Debby can be seen in the wind, wave and tidal measurements taken from both onshore and offshore weather stations around the dual tidal inlets system of John's Pass and Blind Pass, approximately 25 kilometers north of the mouth of Tampa Bay. The energetic and persistent southerly forcing, in addition to higher storm induced water levels and wave heights, resulted in atypical beach erosion and sediment deposition on the ebb tidal deltas of the two inlets and the surrounding beaches. The John's Pass ebb delta gained 60,000 cubic meters of sediment and the Blind Pass ebb delta gained 9,000 cubic meters as a result of the storm. Shoreline position, beach profile and offshore bathymetric surveys conducted before and after Tropical Storm Debby illustrate the changes in the coastal morphology such as the development of an offshore bar south of Blind Pass and erosion of the dry beach north and south of John's Pass. The Coastal Modeling System (CMS) was used to simulate wave and tide-driven current fields during the passage of the storm. The modeled wave field qualitatively illustrated the shadowing effect of the Tampa Bay ebb delta in reducing the southerly approaching storm wave energy arriving at the study area during the storm. The tidal flow patterns through the inlets and over the ebb tidal deltas were considerably different during the storm, as compared to normal tidal cycles.

published_or_final_version / Architecture / Master / Master of Landscape Architecture

Media use of hurricane graphics to apprise populations vulnerable to severe weather provides a persuasive demonstration of the importance and complexity of visual communication. Surprisingly little research, however, has explored how audiences interpret weather graphics. This study examined whether the general public and the National Weather Service share a common understanding of selected weather related terms and meaning of a NWS informational graphic. Using a coorientation model, general public responses to a questionnaire were compared to definitions prescribed by the NWS. Additionally, the public were asked questions to measure trust of the NWS as a credible and reliable source of severe weather information. Selected broadcast meteorologists were surveyed to measure their opinions of the NWS as well as to measure their perceptions of how the general public would respond to questions relating to knowledge of weather terms and graphics. Results revealed discrepancies between the intent of such graphics and audience interpretations. While the vast majority of respondents recognized the Tropical Cyclone Track Watch/Warning Graphic and understood much of the information it conveyed, study respondents did not seem to remember or understand the meaning of the terms Watch and Warning. While these terms or conditions are only one aspect of the graphic they represent critical information for populations at risk. Additionally, the results of this study indicate that weather forecasting professionals' perceptions of the public's understanding of the graphic are inaccurate. Results also show respondents generally rate the NWS as a reliable and competent agency but they do not consistently rate their local weather providers as well. Weather scientists' foremost concern may be the accuracy of their forecasts, but they also must consider the accuracy of the perceptions of those forecasts if they are to be effective in warning populations at risk of severe weather. These results have sobering implications for both governmental and private sources of emergency communication.