This paper describes a study designed to determine average labor and machine times required to implement erosion control and revegetation best management practices (BMPs) for skid trails in Kentucky. Labor and machine activities were recorded for 14,400 feet of skid trail on 10 nonindustrial private logging sites. Water bar construction and reshaping activities such as filling ruts and berm removal were filmed continuously with a video camera and then analyzed using time-motion study techniques. Labor activities for revegetation such as seeding and application of fertilizer were also timed. The average total machine time for retirement activities per 1000 feet was 51 minutes for sites using dozers and 52 minutes for sites using skidders. The average water bar construction time using a bulldozer was 1.5 minutes (n=112) while the average construction time using a skidder was 3.5 minutes (n = 21). The average amount of labor time required to seed 1000 feet of skid trail was 23 minutes (n = 5). Three methods of water bar construction were observed and analyzed to identify differences among them. While there were significant differences among the three methods, the data suggest that skid trail percent slope may have the greatest effect on water bar construction times.

Les Bmps sont des morphogènes appartenant à la superfamille du Tgf-[beta] et sont impliqués dans plusieurs processus cellulaires tels que la prolifération, la migration, la différenciation et le maintien de l'homéostasie autant chez l'embryon que chez l'adulte. La liaison des Bmps aux récepteurs entraîne l'activation au niveau du cytoplasme de facteurs de transcription nommés les BR-Smads (Smadl, 5 et 8). Parmi les rôles attribués à la voie de signalisation des Bmps, très peu d'études ont démontré précisément quels BR-Smads médiaient ces rôles et fonctions. Une étude au sein de notre laboratoire avait préalablement caractérisé les rôles de la voie de signalisation des Bmps au niveau de l'épithélium intestinal suite à la délétion conditionnelle de Bmpr1a chez la souris. Nous avons voulu déterminer les rôles spécifiques de chaque BR-Smad au niveau de l'épithélium intestinal. Nous avons utilisé le système de délétion conditionnelle Cre/loxP afm d'effectuer la délétion individuelle de Smad1, Smad5 ou Smad8 strictement au sein des cellules épithéliales intestinales à l'aide de la Cre recombinase sous le contrôle du promoteur tronqué de la Villine . Des analyses de prolifération et de migration par incorporation de BrdU ont permis de démontrer que Smadl était impliqué dans le contrôle de la prolifération tandis que Smad5 était impliqué dans la migration des cellules épithéliales intestinales. Le marquage des différents types de cellules sécrétrices composant l'épithélium de l'intestin ont été effectués. Les résultats obtenus ont permis de démontrer que les rôles des Bmps dans la différenciation des cellules caliciformes seraient médiés par Smadl et Smad5 alors que Smadl serait le seul BR-Smad impliqué dans la différenciation des cellules de Paneth. Les défauts dans la détermination des cellules entéroendocrines observés chez les souris Bmpr1a[indice supérieur deltaCE1] n'ont pas été observés suite à la délétion individuelle de chacun des BR-Smads. Ce résultat suggère donc la présence d'une compensation entre les divers BR-Sxnads ou que les défauts de la détermination des cellules entéroendocrines nécessitent la perte de deux ou des trois BR-Smads en même temps. Nous avons également généré des modèles cellulaires stables exprimant diverses constructions de shARN contre chaque BR-Smad chez les cellules IEC-6. Les résultats obtenus in vitro confirment l'implication de Smadl dans le contrôle de la prolifération et le rôle de Smad5 dans la migration de cellules épithéliales intestinales. De plus, ces modèles cellulaires permettront l'étude plus approfondie des mécanismes impliqués dans la prolifération et la migration suite à la délétion de Smadl et Smad5 respectivement en plus de faciliter la combinaison de la perte de plusieurs BR-Smads en même temps. Les résultats obtenus démontrent que les BR-Smads ont des rôles distincts au niveau de la prolifération, de la migration et de la différenciation de l'épithélium intestinal, mais suggèrent également que les BR-Smads aient des rôles combinatoires et compensatoires entre eux dans certaines fonctions cellulaires. [symboles non conformes]

Master of Science / Department of Biological & Agricultural Engineering / Stacy L. Hutchinson / Urban stormwater is one of the leading causes of water quality impairment and stream channel degradation in the United States. In an effort to address the negative effects of stormwater runoff on receiving aquatic systems, Best Management Practices for stormwater, including ecologically-designed stormwater systems, are becoming more common across the urban landscape. Throughout eastern Kansas and the rest of the Midwestern United States, prairie grasses are beginning to receive attention for their potential to enhance infiltration within these systems. However, the function of vegetated stormwater systems and the influence of factors such as vegetation age on infiltration and system performance are not well understood because monitoring data for these systems is limited. When performance data is collected, it often pertains only to the hydraulic and water quality aspects of the system but neglects any assessment of the integrity of the ecosystem functions on which the system's performance is dependent. The objective of this study was to address the need for an assessment tool that considers the ecological integrity, or health, of ecologically-designed stormwater systems, as well as to fill the gap in the literature regarding the function of ecologically-designed stormwater systems in the tallgrass prairie region. Since many of the eco-based stormwater practices in the region rely upon the establishment of native prairie grasses to enhance infiltration on the site, the specific focus of this study was to gain a better understanding of infiltration processes in ecologically-designed systems and the extent of our ability to regain these processes through prairie restoration in previously disturbed urban sites. To address these objectives, two stormwater systems at different stages of vegetative maturity were examined. In general, ecosystem health scores were higher for the more mature system and could be used to guide future management decisions at both sites. Results from the hydraulic analysis indicate the function of the system may improve over the course of the growing season, but statistical relationships between system age and infiltration rate could not be established.

This document includes three completed publications to represent Urban Agriculture as a ideal solution to meet the UN Sustainable Development Goals. The first publication (Weaver, 2017a) provided in Chapter Two examines the stormwater Best Management Practices (BMP) modelling parameters for the current EPA Stormwater Management Model (SWMM) as the first step to developing Urban Agriculture BMPs. The second publication (Weaver, 2015) provided in Chapter Three highlights how many high-rated scholars have identified agriculture as a critical driver for the planetary systems impacts we find with community development. The third publication (Weaver, 2017b) provided in Chapter Four breaks down a completely new definition for Urban Agriculture, as the foundational works disagree on meaning, resulting in an ambiguous definition. Together, these publications encourage engineers to model Sustainable Development options with green infrastructure (Weaver, 2017a), distinct from the Planetary Systems impacts of other contemporary options (Weaver, 2015), with a greater understanding of the social capital to engage stakeholders in meeting the UN Sustainable Development Goals (Weaver, 2017b).

This dissertation presents three chapters of contemporary research in environmental and development economics. Each chapter echoes a common theme, in that achievement of regional goals constitute 'Wicked Problems' and that the approaches that parties may take to address these specific regional goals may have complex interactions with other regional goals. Decision-making, cost analysis, and multipurpose efficacy of the approaches that regional parties may take to achieve goals are evaluated in environmental and development contexts and implications for program analysis and policy design are discussed. The first chapter of this dissertation seeks to understand how regulated parties, i.e. Municipal Separate Storm Sewer Systems (MS4s), choose from the strategies at their disposal to achieve compliance with their Chesapeake Bay Total Maximum Daily Load (TMDL) obligations. To address declining Chesapeake Bay water quality, the United States Environmental Protection Agency (EPA) set extensive nutrient and sediment reduction goals under the 2010 Chesapeake Bay TMDL. Virginia has responded by passing along explicit nutrient and sediment reduction requirements to its MS4s, which can choose from a variety of urban stormwater, land use change, source control, and restoration practices to achieve reductions toward these requirements. MS4s in Virginia have also been granted flexibility to achieve reduction requirements through purchase of nutrient and sediment credits toward requirements through trade. In spite of the cost-savings that these credits provide, MS4s' interest in trading for these credits has been low. MS4s instead generally engage in onsite nutrient and sediment reduction themselves, in spite of the high costs of doing so. In response to low interest in trade, case analysis of MS4s' Bay TMDL compliance behavior and semi-structured interviews are conducted to better understand the role of trade in compliance strategy and the reasons for its non-use. Findings reveal that the Virginia MS4s studied typically choose to implement onsite urban stormwater practices, source control practices, and restoration practices in order to generate long-lasting local benefits, like erosion control, flood risk reduction, and progress toward local TMDL obligations, alongside reductions toward the Bay TMDL. MS4s refrain from term credit purchases out of concern over future availability and refrain from perpetual credit purchases because they have been able to use funding sources to achieve reductions from long-lasting onsite practices at similar per-pound costs, while also receiving local benefits. Implications are that supply-side efforts to support trade markets may not generate the level of activity expected, given that would-be buyers have generally limited interest in trade as a compliance strategy. The second chapter studies the degree to which the practices used to meet local TMDL water quality obligations contribute to Bay TMDL compliance for the Loudoun County MS4. Linear programming is used to estimate the minimal cost of achieving Bay compliance in addition to local obligations through representative nutrient and sediment reduction strategies. The model estimates that Loudoun County MS4 faces substantial costs just to meet local water quality goals ($11 million/yr). Since many of the actions taken to meet local water quality goals also generate pollutant reductions to the Chesapeake Bay, adding Bay TMDL obligations adds 0.2%, 3%, and 32.9% to these costs, depending on the water quality trading used to reach Bay TMDL compliance. Findings shed additional light on Chapter 1's goal of investigating the role of trade by explaining low interest in trade as stemming from heavy local water quality needs. Implications are that the burden imposed by the Bay TMDL may not be as high as generally thought. The third chapter shifts focus to the Opioid Crisis to evaluate the efficacy of Syringe Exchange Programs, best known for their efforts to prevent bloodborne illness transmission, at achieving their secondary intervention goal of preventing opioid overdose. While research has established that Syringe Exchange Programs, or SEPs, are effective at preventing bloodborne illness, little focus has been given to their ability to prevent fatal overdose, which they aim to do by engaging in intervention practices like naloxone and fentanyl test strip distribution. In response for need for understanding of Syringe Exchange Programming's impact on overdose, fixed effects analysis is used to empirically study the impact of county-level SEP in North Carolina following the state's 2016 SEP legalization. Need-based programming complicates analysis and likely biases findings of the impact of SEP on overdose upward. Regardless, findings consistently fail to find that SEP has a significant effect on fatal overdose from four categories of opioids, which should reduce concerns in recent literature that they may increase overdose death. Implications are that, since SEPs have a richly documented history of saving lives through the prevention of bloodborne illness and do not appear to increase overdose, contrary to findings in other work, policy makers should continue to incorporate SEP into their portfolio of strategies used to address the Opioid Crisis. / Doctor of Philosophy / This dissertation presents three chapters of contemporary research in environmental and development economics. Each chapter echoes a common theme, in that achievement of regional goals constitute 'Wicked Problems' and that the approaches that parties may take to address these specific regional goals may have complex interactions with other regional goals. Decision-making, cost analysis, and multipurpose efficacy of the approaches that regional parties may take to achieve goals are evaluated in environmental and development contexts and implications for program analysis and policy design are discussed. The first chapter of this dissertation seeks to understand how regulated parties, i.e. Municipal Separate Storm Sewer Systems (MS4s), choose from the strategies at their disposal to achieve compliance with their Chesapeake Bay Total Maximum Daily Load (TMDL) obligations. To address declining Chesapeake Bay water quality, the United States Environmental Protection Agency (EPA) set extensive nutrient and sediment reduction goals under the 2010 Chesapeake Bay TMDL. Virginia has responded by passing along explicit nutrient and sediment reduction requirements to its MS4s, which can choose from a variety of urban stormwater, land use change, source control, and restoration practices to achieve reductions toward these requirements. MS4s in Virginia have also been granted flexibility to achieve reduction requirements through purchase of nutrient and sediment credits toward requirements through trade. In spite of the cost-savings that these credits provide, MS4s' interest in trading for these credits has been low. MS4s instead generally engage in onsite nutrient and sediment reduction themselves, in spite of the high costs of doing so. In response to low interest in trade, case analysis of MS4s' Bay TMDL compliance behavior and semi-structured interviews are conducted to better understand the role of trade in compliance strategy and the reasons for its non-use. Findings reveal that the Virginia MS4s studied typically choose to implement onsite urban stormwater practices, source control practices, and restoration practices in order to generate long-lasting local benefits, like erosion control, flood risk reduction, and progress toward local TMDL obligations, alongside reductions toward the Bay TMDL. MS4s refrain from term credit purchases out of concern over future availability and refrain from perpetual credit purchases because they have been able to use funding sources to achieve reductions from long-lasting onsite practices at similar per-pound costs, while also receiving local benefits. Implications are that supply-side efforts to support trade markets may not generate the level of activity expected, given that would-be buyers have generally limited interest in trade as a compliance strategy. The second chapter studies the degree to which the practices used to meet local TMDL water quality obligations contribute to Bay TMDL compliance for the Loudoun County MS4. Linear programming is used to estimate the minimal cost of achieving Bay compliance in addition to local obligations through representative nutrient and sediment reduction strategies. The model estimates that Loudoun County MS4 faces substantial costs just to meet local water quality goals ($11 million/yr). Since many of the actions taken to meet local water quality goals also generate pollutant reductions to the Chesapeake Bay, adding Bay TMDL obligations adds 0.2%, 3%, and 32.9% to these costs, depending on the water quality trading used to reach Bay TMDL compliance. Findings shed additional light on Chapter 1's goal of investigating the role of trade by explaining low interest in trade as stemming from heavy local water quality needs. Implications are that the burden imposed by the Bay TMDL may not be as high as generally thought. The third chapter shifts focus to the Opioid Crisis to evaluate the efficacy of Syringe Exchange Programs, best known for their efforts to prevent bloodborne illness transmission, at achieving their secondary intervention goal of preventing opioid overdose. While research has established that Syringe Exchange Programs, or SEPs, are effective at preventing bloodborne illness, little focus has been given to their ability to prevent fatal overdose, which they aim to do by engaging in intervention practices like naloxone and fentanyl test strip distribution. In response for need for understanding of Syringe Exchange Programming's impact on overdose, fixed effects analysis is used to empirically study the impact of county-level SEP in North Carolina following the state's 2016 SEP legalization. Need-based programming complicates analysis and likely biases findings of the impact of SEP on overdose upward. Regardless, findings consistently fail to find that SEP has a significant effect on fatal overdose from four categories of opioids, which should reduce concerns in recent literature that they may increase overdose death. Implications are that, since SEPs have a richly documented history of saving lives through the prevention of bloodborne illness and do not appear to increase overdose, contrary to findings in other work, policy makers should continue to incorporate SEP into their portfolio of strategies used to address the Opioid Crisis.

Exploitation of groundwater and excess nutrient runoff are major issues plaguing agriculture and streams in the Lower Mississippi River Basin, and increased irrigation intensity has yielded a proportionate increase in water use. Quantifying the use and effects of conservation practices like on-farm water storage (OFWS) systems will justify continued adoption of these practices to mitigate groundwater decline and nutrient runoff. Since 2010, over 795 hectares of surface water storage has been added in the Big Sunflower River Watershed, and analysis of aquifer saturation shows a recent rise in the water table and a decrease in seasonal water table drawdowns. Modeling pre- and post- construction conditions of a small agricultural subwatershed shows little difference in runoff at the watershed outlet after the construction of an OFWS system, but field monitoring and modeling show more water retained within the system and the importance of management to maximize the benefits of conservation practices.

Sediment is a prevalent non-point source pollutant associated with forest operations. Roads and skid trail surfaces have erosion rates that are greater than the harvest area. Forestry best management practices (BMPs) have been developed to minimize erosion on skid trails, but few projects have compared the effectiveness of different BMPs for bladed skid trails in the mountains. This project evaluated soil erosion rates from bladed skid trails in the Ridge and Valley physiographic region of Virginia following an operational timber harvest. Skid trails were assigned into six blocks where each block had similar slopes and soils. All BMP treatments had waterbars, which are considered the minimum acceptable BMP closure treatment. Each block contained four different skid trail closure BMP treatments (waterbar only (Control), slash-covered (Slash), seeded (Seed), and seeded with fertilizer and mulch (Mulch)). The 24 treatment units were isolated with waterbars and installed following the Virginia Department of Forestry (VDOF) BMP guidelines. The randomized complete block design had three slope class ranges: gentle (0%-10%), moderate (11%-20%), and steep (21%-30%). Stormwater runoff from skid trails was directed at downslope waterbars and eroded material was trapped in silt fences at each treatment area. Depth and area of eroded soil collected in silt fences was measured monthly to quantify total erosion volume for the skid trail area and converted to a per acre basis. Volumes were converted to mass using soil bulk density within the trapped sediment. Control treatments had an average erosion rate of 6.8 tons ac-1 yr-1, with rates up to 73.5 tons ac-1 yr-1 following installation and during extreme rainfall events. Seed treatments recorded an average erosion rate of 2.6 tons ac-1 yr-1, with rates reaching 27.2 tons ac-1 yr-1. Adding grass seed provided ground cover, but not consistently over time. Due to high rates of ground cover, the Mulch treatments averaged 0.5 tons ac-1 yr-1 with an extreme of 3.8 tons ac-1 yr-1. Slash treatments were found to reduce erosion rates to an average of 0.4 tons ac-1 yr-1, with the highest rate being 1.8 tons ac-1 yr-1. Site characteristics on experimental units were collected quarterly in order to model erosion rates with commonly used erosion models for forestland (USLE-Forest, RUSLE2, WEPP:Road). Direct erosion estimates were compared to erosion model predictions produced by USLE-Forest, RUSLE2, and WEPP:Road in order to partially confirm the relationship between sediment trap data and the models. Using multiple analyses it was determined that USLE-Forest and RUSLE2 predicted mean values that are more similar to the actual measured rates, RUSLE2 and WEPP:Road have better linear relationships to the measured rates than does USLE-Forest, and USLE-Forest was the most statistically similar to the measured data using a nonparametric Steel-Dwass Multiple Comparisons Test. All models performed inadequately when attempting to predict Control or Slash treatments; while all models performed the best at predicting Mulch treatments. / Master of Science

The Virginia Runoff Reduction Method (RRM) was adopted in 2014 as a compliance tool for evaluation of stormwater volume and quality, and necessitates use of urban stormwater best management practices (BMPs) to meet regulatory standards. Coastal Virginia is characterized by flat terrain, shallow water tables, and low permeable soils that may limit the application of BMPs as recommended by state regulations. Soil morphological features are often used to estimate the seasonal high water table (SHWT) for initial feasibility, but existing soil data misrepresented expected SHWT depths in the Virginia Beach, VA, study area. A GIS-based methodology relying on perennial surface water elevations and USGS groundwater monitoring data was developed to estimate the SHWT depth in Virginia Beach. The SHWT map was shown to be consistently more reliable than available predictions based on soil morphology, and was used as input to a BMP siting tool. The tool, known as BMP Checker, was developed to explore how flat terrain, shallow water tables, and poor soils influence BMP siting in coastal Virginia. The BMP Checker algorithm was validated on 11 Virginia Beach sites before application on 10,000 ft2 (929 m2) area sections across the city. Citywide application showed that the most widely applicable BMPs in the study area include wet ponds that intercept groundwater and constructed wetlands. Conversely, sheet flow to conservation area and infiltration practices are the least applicable. Because the RRM assigns more credit to infiltration-based practices, sites in Virginia Beach may find it difficult to meet regulatory standards. / Master of Science

Sediment is one of the leading non-point source pollutants in the U.S and has detrimental effects on biological communities such as aquatic communities; human use such as recreation; and natural processes such as flood water storage. For silvicultural operations, the majority of sediment is produced from erosion on highly disturbed areas, such as skid trails, haul roads, and log landings. Erosion from silvicultural activities not only has the potential to introduce sediment into waterways but can also decrease site productivity through the removal of topsoil. In order to minimize erosion from silvicultural operations, forestry Best Management Practices (BMPs) have been developed, but efficacies of various BMP options are not well documented. This study evaluated five closure and cover BMPs for the control of erosion on bladed skid trails through both field based measurements with sediment traps and soil erosion modeling. The erosion models used were the Universal Soil Loss Equation for Forestry (USLE – Forest), the Revised Universal Soil Loss Equation version 2 (RUSLE2), and the Water Erosion Prediction Project for Forest Roads (WEPP – Forest Roads). Erosion model predictions were also regressed against field based results to determine accuracy. The bladed skid trail BMP treatments evaluated were: 1) water bar only (Control); 2) water bar and grass seed (Seed); 3) water bar, grass seed, and straw mulch (Mulch); 4) water bar and piled hardwood slash (Hardwood Slash); and 5) water bar and piled pine slash (Pine Slash). Field based results show that the Control treatment was the most erosive (137.7 tonnes/ha/yr), followed by the Seed treatment (31.5 tonnes/ha/yr), Hardwood Slash treatment (8.9 tonnes/ha/yr), Pine Slash treatment (5.9 tonnes/ha/yr), and finally the Mulch treatment was the most effective erosion control technique (3.0 tonnes/ha/yr). Model accuracy results show that RUSLE2 performed the best overall. Both USLE – Forest and WEPP – Forest Roads under predicted values on the Control treatment, where erosion rates were very high. WEPP – Forest Roads under predicted these values the most. All models generally show that the Control was the most erosive followed by the Seed, Hardwood Slash, Pine Slash, and Mulch treatments. / Master of Science

Water quality practices can have a financial impact on the cost of harvesting timber in Virginia. Two hundred seventy-two timber harvesters were surveyed to determine the estimated cost for implementing best management practices (BMPs) on harvested sites. BMPs analyzed in this study are pre-harvest planning, road construction, broad base dips, water turn-outs, water bars, streamside management zones, stream crossings, and site stabilization. Loggers provided an estimate of the cost or expense for constructing each BMP. They gave an indication of how costly these practices were to implement. The responses for each BMP were then stratified by region to determine if there were regional differences in the unit costs. With the exception of haul road construction costs, the data showed no regional differences in the unit BMP costs across Virginia. Forty-six harvested sites in Virginia were visited to determine the number of BMPs constructed for the harvesting operations. The total cost of following BMP guidelines was calculated using the state median cost, regional road construction costs, and number of practices installed on the site for each tract. The BMP cost per acre was reported by region. / Master of Science