Stormwater runoff is a major environmental concern, particularly in urban environments. Trends in managing stormwater have evolved (and continue to evolve) from a quantity only approach into a sustainable approach, which integrates quantity, quality, the environment, and aesthetics. Best management practices (BMPs) and Low Impact Development (LID) are two well-documented techniques capable of managing to sustainable standards. There are a number of stormwater models available to design professionals today. However, there are few which integrate site-scale BMP/LID analysis in a simplified fashion. The purpose of this study is to determine if there is a demand in the design profession for simplified stormwater modeling tools to help designers make informed decisions about integrating BMP/LID strategies into site plans. A Web-based questionnaire was administered to a group of design professionals to determine their knowledge of BMPs and their technological needs and preferences in meeting stormwater goals and requirements.

Urban stormwater management is evolving toward sustainable approaches which rely on dispersed small-scale bioretention BMPs. One such BMP is the flow-through planter, commonly applied in areas where infiltration into in situ soil is restricted or not possible. A project was developed to evaluate 18, vertically scaled flow-through mesocosms. Three replicates of six treatments, including four soil mixtures containing varied percentages of sand, compost and topsoil, were tested for orthophosphate and nitrate removal, volume reduction capabilities, and peak flow attenuation through the application of a synthetic solution over a simulated 2-inch, Type II storm event. Runoff volume was significantly (p < 0.05) reduced compared to controls. Nutrient levels observed along the hydrograph at different time-steps and flow rates revealed patterns not apparent in cumulative results. The observation of preferential flow patterns along with variability in nutrient removal across treatments highlights the need for design modifications of flow-through facilities.

The onarm water storage (OFWS) systems at Metcalf and Pitts farm in Porter Bayou Watershed were monitored for changes in nutrient levels and water withdrawal for irrigation from March 2012 to April 2013. Nitrogen and phosphorus levels were generally higher during the early part of the growing season. The OFWS systems can reduce nitrate and phosphorus in runoff up to 81% and 85%, respectively. However, the systems did not consistently reduce sediment and nutrients especially after significant rainfall and runoff events. The systems provided a total of 130 and 233 acreeet of recycled water for irrigating crops at Metcalf and Pitts, respectively, during the 2012 growing season. These amounts reflect significant savings in terms of groundwater. This study highlights the advantages of OFWS systems as structural BMPs to reduce nutrient loading into the Gulf of Mexico and to minimize groundwater withdrawals from the Mississippi Alluvial Aquifer.

This research conducted a GIS analysis of twenty-eight sub-watersheds in Massachusetts and considered five factors which the literature suggested influenced base flow. The literature suggested a positive relation between precipitation, forest cover and base flow and a negative relationship between impervious surfaces, soil drainage class, slope and base flow. A multiple regression analysis of the sub-watershed information confirmed the literature for two factors (soil drainage class and slope) and questioned it on three factors (impervious surfaces, precipitation, and forest cover). The resulting predictive equation indicated that imperviousness and precipitation were the most significant factors affecting base flow. The first derivative of the predictive equation indicated that the interaction effects between these factors had a substantial impact on the base flow values. A number of land use impacts were also considered in this research. Natural land use features such as open land, wetland, forest cover, agricultural, and recreation uses were found to promote the infiltration and increase base flow. These uses promote base flow because their surfaces are more pervious than unnatural surfaces such as high density/multi-family residential, industrial and commercial areas which are mostly covered by impervious surfaces reducing base flow. The research also used a case study of two Massachusetts sub-watersheds to consider the effectiveness of structural stormwater Best Management Practices for promoting base flow. Two sub-watersheds were considered: the Neponset where stormwater BMPs had been implemented and Quinsigamond that had not implemented them. The case study results suggested that structural stormwater BMPs were effective in increasing base flow.

Excessive nutrient concentrations from a different point and non-point sources are the main cause of water impairment in the United States. Appropriate management practices, according to the source and quantity of pollutions, need to be implemented to control excessive nutrient influx in the water body. Various types of hydrological and water quality models with diverse function, capability and degree of complexity are employed to quantify watershed hydrologic processes and nutrient pollution. Multiple models can be applied to a watershed but the suitable model must be selected based on watershed type and simulation need. Two watershed-scale models, Soil and Water Assessment Tool (SWAT) and Hydrologic Simulation Program-Fortran (HSPF) were chosen for this study to simulate runoff, sediment yield, and nutrient load from the Big Sunflower River Watershed (BSRW) of Mississippi. The objectives of this study are to access the nutrient sources within the watershed, determine the appropriate model to quantify them, develop and evaluate model considering spatial and temporal variations in input data, and evaluate the effectiveness of different Best Management Practices (BMPs) on surface runoff, sediment yield and nutrient load at watershed scale. This study has identified a potential source of nutrients in BSRW and provided a suitable BMP for its management. Similarly, the study found both SWAT and HSPF were efficient in the simulation of streamflow, sediment yield and nutrient load, where SWAT was more efficient during simulation streamflow and sediment yield. Likewise, the study established that both water-quantity and water-quality are sensitive to the change in LULC data layers and thus, seasonal LULC data applied to SWAT will better explain variation in hydrology and water quality as compared to the annual cropland data layer. Moreover, the study showed that well managed vegetative filter strip was very efficient in reducing sediment yield, TN, and TP at both field and watershed scale among different BMPs evaluated at field and watershed scale. This study will be beneficial in developing efficient nutrient management strategy at field and watershed scale, selecting appropriate model and input according to the need and type of watershed, and providing further research opportunities to the scientific community.

This PhD dissertation work delves into critical issues within the forestry business related to carbon sequestration, land value maximization and climate change vulnerability. The study proposes different tools to enhance the efficiency and outcomes of forest practices. Chapter two involves an enhanced forest rotation deferral methodology for carbon dioxide sequestration, focusing on the forest's final product destination passed the Faustmann optimal rotation age. Instead of giving the same value for pulp wood and saw timber, the research acknowledges the benefit of increased carbon dioxide stored in saw timber materials. To drive landowners to the socially optimum rotation age, where the marginal benefits of extended carbon storage equal the private marginal cost of postponing forest rotation, an incentive based mechanism is proposed, using subsidies. Through sensitivity analysis on the underlying assumptions, the socially optimal rotation is consistently greater than the currently applied one-year harvesting deferral, and smaller than longer extensions, such as 20 years deferred rotations. In chapter three, a novel approach to design Streamside Management Zones widths that vary according to different landscape characteristics is presented, as opposed to the constant command and control width currently used in Virginia. This adaptive approach allows landowners to maximize land value, while ensuring water quality protection. To determine the sediment retention equation as a function of SMZ slope, width, and soil texture, we use data derived from the Watershed Erosion Prediction Project. By simulating different regulatory constraints concerning accepted sediment delivery, the study shows the tradeoff between water quality and land expectation value through the changes in the opportunity cost of Streamside Management Zones. Lastly, chapter four centers on a dataset collected in India about tree planting species choice followed by a second model that incorporates socio-economic, as well as revealed preference management choices, and tree planting species as explanatory variables in a binary crop loss model. The findings reveal that tree planting, except for fruit trees, compared to agricultural crops, diminishes the household's probability of facing losses due to climate change, extreme weather events and pest attacks. Specifically, there is a 14.4% reduction in the probability of facing a loss when planting Eucalypt and Casuarina trees, a 7.6% reduction when planting palm trees, and 13.5% reduction when planting multiple trees, which evidences how trees are less vulnerable. Throughout this dissertation, the interdisciplinary research uses rigorous methodologies, comprehensive data analysis, and environmental economics theoretical foundation, culminating in valuable insights and potential policy recommendations to enhance forest practices in environmental challenging times. / Doctor of Philosophy / Climate change is a reality and forest practices can help us mitigate some of its consequences. However, forest practices are driven by private decisions that prioritize individual net benefits, often neglecting the broader ecosystem services forests provide. To enhance the collective benefits that forests provide to society, while maximizing the private economic return, it is crucial to employ tools to drive landowners to a socially optimal outcome. This dissertation aims to improve forest practices in three key environmental areas: carbon dioxide sequestration, land value optimization with water quality conservation, and crop vulnerability. The second chapter introduces a novel harvesting deferral methodology for carbon dioxide sequestration, which assigns greater value for saw timber production due to its longer product lifespan, thereby enhancing carbon dioxide sequestration away from the atmosphere. We align private landowner and social planner's interests and propose a subsidy scheme to incentivize landowners to postpone their forest rotation age until the marginal cost of doing so equals the societal marginal benefit of the deferred rotation. The outcomes are contingent on the underlying assumptions, and in this study, all rotation deferrals were greater than the current one-year rotation deferral contract, and smaller than 20 years. In the third chapter, an alternative approach to defining Streamside Management Zones (SMZ) width is proposed. Rather than employing a fixed width value across various conditions, a varied SMZ width is suggested, according to specific landscape characteristics. The study formulates the landowner's maximization problem, which is constrained to a fixed sediment delivery value. By simulating sediment retention delivery data using the Watershed Erosion Prediction Project, the research shows the opportunity cost of water quality through forgone timber revenue. Lastly, considering the direct link between climate change and food security, the dissertation utilizes data collected in India on household characteristics and revealed management choices. The first objective is to model the factors influencing the tree species planting decision, followed by a second model that focuses on how tree planting may reduce the probability of facing losses. The findings indicate that tree planting, except for fruits, reduces the probability of losses compared to planting agricultural crops. Throughout the dissertation, different methodologies, data analysis, and interdisciplinary research with potential policy implications are presented.

No description available.

No description available.

No description available.

No description available.