Best management practices (BMPs) are used in the nursery and greenhouse industry to increase production efficiency, and also serve to help meet clean water limitations on contaminants entering waters such as the Chesapeake Bay Watershed. Research is lacking on which BMPs are most widely used or most efficacious for Virginia nursery and greenhouse growers. Objectives of this work were to determine BMP use, barriers to adoption, and scientific efficacy. We conducted a survey of Virginia growers to find the 1) most widely used BMPs, 2) reasons behind BMP use, and 3) any barriers to BMP adoption. Sixty growers (17%) responded to the survey. The most widely used BMPs included irrigation scheduling, integrated pest management, optimized irrigation efficiency, plant need based watering, grouping plants by water needs, on-site water capture and collection, and use of controlled-release fertilizers (CRFs). Cost was a barrier to BMP adoption, and environmental concern was a commonly reported reason for BMP use. We documented the science supporting selected water-related BMPs (grass buffer strips, CRFs, and irrigation optimization BMPs). Providing the science supporting BMP use gives growers confidence in implementing BMPs to limit water contamination, and prevent waste. / Master of Science / Best management practices (BMPs) are used in the nursery and greenhouse industry to increase production efficiency, and also serve to help meet clean water limitations on contaminants entering waters such as the Chesapeake Bay Watershed. Research is lacking on which BMPs are most widely used or most efficacious for Virginia nursery and greenhouse growers. Objectives of this work were to determine BMP use, barriers to adoption, and scientific efficacy. We conducted a survey of Virginia growers to find the 1) most widely used BMPs, 2) reasons behind BMP use, and 3) any barriers to BMP adoption. Sixty growers (17%) responded to the survey. The most widely used BMPs included irrigation scheduling, integrated pest management, optimized irrigation efficiency, plant need based watering, grouping plants by water needs, onsite water capture and collection, and use of controlled-release fertilizers (CRFs). Cost was a barrier to BMP adoption, and environmental concern was a commonly reported reason for BMP use. We documented the science supporting selected water-related BMPs (grass buffer strips, CRFs, and irrigation optimization BMPs). Providing the science supporting BMP use gives growers confidence in implementing BMPs to limit water contamination, and prevent waste.

Farmyard runoff, i.e. the effluent generated by the rain falling over farmyards, tracks and roofs, is a significant and overlooked source of nutrients and pathogens which degrades aquatic ecosystems through eutrophication, siltation and wildlife poisoning, raises public health concerns, and incurs considerable costs for society. Among other Best Management Practices implemented to address agricultural water pollution and help achieve compliance with the Water Framework Directive, Constructed Farm Wetlands (CFWs), i.e. shallow surface flow wetlands comprising several vegetated cells in series, are being recommended for remediation of farmyard runoff, due to their capacity to remove or store pollutants. Investigation is therefore needed of their long-term water treatment efficiency and ecological value to optimize their design and cost-effectiveness and minimize their negative externalities. The main aims of this study were to: 1) evaluate the treatment performance of CFWs and the link between design, hydrology and efficiency; 2) assess their ecological value and the influence of water quality and design on wetland ecology; 3) identify their costs, benefits and the way they are perceived by farmers; and 4) inform guidelines for the design, construction and aftercare of sustainable CFWs. Research focused on two CFWs in south-east Scotland, one at a dairy farm and one at a mixed beef-arable farm, which receive runoff from yards and roofs, field drainage and septic tank overflow. From February 2006 to June 2008, rainfall, evaporation, water levels and flow at the CFWs were monitored, and their treatment efficiency was assessed from water samples collected manually regularly or with automatic samplers during storm events, and analysed using standard methods. In addition, their ecological value was assessed twice a year from vegetation and aquatic macroinvertebrate surveys. Finally, semi-structured interviews with eight farmers and a farm advisor and discussions with three CFW designers in Scotland and Ireland allowed collection of technical and economic data on farm practices, CFW construction and maintenance, and helped assess CFW cost-effectiveness and acceptance by farmers. Both CFWs reduced pollutant concentrations between inlet and outlet, with efficiencies at CFW1 and CFW2 respectively of 87% and < 0% for five-day biochemical oxygen demand, 86% and 83% for suspended solids, 68% and 26% for nitrate/nitrite, 42% and 34% for ammonium, and 12% and 31% for reactive phosphorus. Nevertheless, the concentration of all pollutants at the outlet of CFW1, and concentration of nitrate/nitrite at the outlet of CFW2 frequently exceeded river water quality standards. Water treatment efficiency varied seasonally, being significantly lower in winter, mainly due to lower temperatures, increased volume of inputs and reduced residence time. The ecological value of the two CFWs differed greatly. At CFW1 and CFW2 respectively, 14 and 22 wetland plant species and 24 and 46 aquatic macroinvertebrate species (belonging to 13 and 27 BMWP scoring families respectively) were recorded, illustrating the greater biodiversity conservation value of CFW2, which was one year older, larger, cleaner, comprised several ponds with a combination of open water and densely vegetated areas, and was subsequently more structurally diverse. The socio-economic study revealed that, despite significant costs associated with their construction (£20 000-£50 000 ha-1) and maintenance (£900-£1500 ha-1 yr-1), CFWs may still represent a more cost-effective alternative than conventional methods. However, their adoption, implementation and sustainable use by farmers were conditioned by land availability and suitability, existing farm infrastructure, detailed information on limitations and maintenance requirements, and adequate financial support for both construction and aftercare. To ensure a long-term, consistent and efficient water treatment, and to enhance biodiversity and landscape, well-maintained, large, vegetated, multi-cell CFWs with shallow overflows are recommended. Their size should be adapted to local precipitation patterns and catchment characteristics. Keywords: agriculture, best management practice (BMP), biodiversity, constructed farm wetland (CFW), costs, farmyard runoff, water pollution, water treatment.

Changing weather patterns, the declining social fabric of rural communities, and economic uncertainty increasingly pose challenges to Vermont communities. The socially and environmentally embedded production practices within sustainable agriculture present a potential solution to these problems. In order to make the most of the potential benefits of these practices society must maximize their adoption. This requires an understanding of both farmer adoption of these practices and consumer perceptions of the resulting food products. This thesis contributes two original articles on sustainable agriculture through the analysis of factors driving both farmer adoption and consumer perceptions of products and practices often thought of as sustainable. The first article seeks to understand farmer adoption of climate change best management practices (CCBMPs). Farmer perceptions of risk and profitability of best management practices (BMPs) are key determinants of adoption, which traditional incentive programs like the Environmental Quality Incentives Program (EQIP) attempt to address by providing financial and technical support. To ensure appropriate price points are offered through these programs, regional price structures must be based upon locally established costs. Thus, this article focuses on the economic cost of implementing and maintaining CCBMPs for twelve diverse farms in Vermont. Specifically, three CCBMPs for Vermont are examined: cover cropping, management intensive rotational grazing (MIRG), and riparian buffer strips. Results of a yearlong farmer based data collection process indicate that the average cost for cover cropping is $129.24/acre, for MIRG is $79.82/acre, and for a tree based riparian buffer strip is $807.33/acre. We conclude that existing incentive payments for cover cropping and MIRG are below costs, likely resulting in under-adoption. The second article reports on a study which seeks to understand the factors influencing Vermont consumer perceptions of raw milk safety. While this article makes no assertion regarding the sustainability of raw milk, an association is established between the motivations for raw milk consumption and sustainable agriculture support. Vermonterâ??s appear to be continuing the trend of consuming raw milk at an increasing rate despite continued declarations from local and national public health officials that raw milk is too microbiologically dangerous to justify its consumption. Thus this study was designed to increase understanding of the factors driving consumer perceptions of raw milk safety. A conceptual model was developed to establish potential factors and related questions were incorporated into the 2014 Vermonter Poll. Resulting data were analyzed using a Probit regression analysis. We conclude that observable factors have the greatest influence on perceptions of raw milk safety. Specifically, perceived health benefits, presence of children in the household, and taste all influence perceptions of raw milk safety.

Addressing climate change is a major undertaking. Agricultural soil has the potential to assist in decreasing the concentration of GHGs in the atmosphere by storing CO2 in the soil. Carbon offset markets have been suggested as a cost effective means of reducing GHG emissions. Farmers can increase their soil sink potential by applying Beneficial Management Practices (BMPs) that enhance carbon sequestration through improvements to soil, nutrient and livestock management practices (Fulton et. al., 2005). Whether or not a market for carbon offsets will emerge depends on a number of factors which mainly are related to the profitability of the BMPs and the costs of implementing a carbon contract. Provided that a market for carbon offsets emerges, the effectiveness of the market depends, in part, on the degree to which buyers and sellers in the market comply with the terms of the contracts they sign. The resource costs associated with monitoring and verification may result in incomplete monitoring. As long as monitoring is not perfect, non-compliance will be an issue. <p>The analysis that will be performed in this thesis introduces non-compliance in the economic analysis of carbon-offset market. The purpose of this work is to examine the overall cost effectiveness of the carbon-offset market when introducing non-compliance. <p>Firstly the theoretical model investigates the incentives for different farmers to participate in the carbon offsets market as well as incentives for engaging in cheating. The model recognizes farmers heterogeneity with respect to cost differences and examines the economic determinants of farmers non-compliance as well as the consequences of non-compliance on the performance of the carbon-offset market. Results support the standard finding that the extent of producers non-compliance decreases with an increase in the audit probability and/or an increase in the penalty per unit of non-compliance. In addition, the number of producers participating in the carbon offsets market is shown to increase with an increase in the carbon-offset price.<p> The analysis then introduces intermediaries in the market that will take care of trading carbon offsets as well as monitoring producers. The traders role in this study is played by an IOF (investor owned-firm) or a PA (producers association). Within the IOF, the analysis focuses on the monopoly and oligopoly structures. The key role of the traders is to guarantee, based on the amount of monitoring that is undertaken, that the emitters purchase only carbon offsets that actually correspond to sequestered carbon. The analysis then examines three cases for the group that monitors farmers compliance a group owned by for-profit traders, a government-run agency and a group owned by the PA trader. This part of the thesis examines what impact the involvement of the traders in the carbon-offset market has on non-compliance, as well as how the structure of the monitoring group affects non-compliance and the amount of carbon offsets traded in the market. The results of the analysis show that the monitoring groups always undertake sufficient monitoring to ensure that full compliance is achieved thus, while non-compliance is possible, it does not occur in equilibrium. The finding suggests that the formation of a government monitoring agency can potentially increase traded output and lower the price paid by emitters, still these changes are likely to be small, particularly when the trading sector is monopolistic. The overall analysis in this chapter shows that the optimal amount of enforcement, and as a result the cost effectiveness of a carbon-offset market, depends on the nature of the organization that undertakes the enforcement. <p>The next consideration of the thesis is the heterogeneity attributed to the timing of sequestration by different farmers. The analysis focuses on the carbon offsets pooling by considering two structures for the aggregator: a for-profit aggregator and a producers association. Pooling resources enables the farmers to benefit from economies of scale. The pricing schedule used by the aggregator is a two-part tariff. The two-part tariff is used as a way of providing an incentive for the farmers sequestering large amounts of carbon to participate in the pool. The study considers two alternatives for the coefficients that might be used to decide on the amount of carbon offsets to which each farmer will be entitled: default coefficient and custom coefficients. Each situation is modeled in a principal agent framework. <p>The analysis examines how the aggregator will target the monitoring service for different group of farmers. The investigation reveals that, under different scenarios, a PA or a FPA (for-profit aggregator) might lead to the formation of a heterogeneous pool or a homogeneous pool of each type. <p>The last issue investigated in this dissertation is the coexistence of a FPA and a PA in the default coefficient case. The analysis show that both aggregator structures can exist together in the market in the same time if the savings in the monitoring costs made possible by the PA are smaller than the cost of organizing the pool. If this condition is not satisfied the FPA cannot survive in the market and the producers association will dominate. <p>In addition to providing a better understanding of how the carbon-offset market may perform when introducing non-compliance, the results of this study can assist in assessing the cost effectiveness of the carbon-offset market when enforcement is undertaken by different organizations. Furthermore, the last consideration of the pooling option might help in selecting which type of pool a heterogeneous or a homogeneous one might perform better under different alternatives.

Addressing climate change is a major undertaking. Agricultural soil has the potential to assist in decreasing the concentration of GHGs in the atmosphere by storing CO2 in the soil. Carbon offset markets have been suggested as a cost effective means of reducing GHG emissions. Farmers can increase their soil sink potential by applying Beneficial Management Practices (BMPs) that enhance carbon sequestration through improvements to soil, nutrient and livestock management practices (Fulton et. al., 2005). Whether or not a market for carbon offsets will emerge depends on a number of factors which mainly are related to the profitability of the BMPs and the costs of implementing a carbon contract. Provided that a market for carbon offsets emerges, the effectiveness of the market depends, in part, on the degree to which buyers and sellers in the market comply with the terms of the contracts they sign. The resource costs associated with monitoring and verification may result in incomplete monitoring. As long as monitoring is not perfect, non-compliance will be an issue. <p>The analysis that will be performed in this thesis introduces non-compliance in the economic analysis of carbon-offset market. The purpose of this work is to examine the overall cost effectiveness of the carbon-offset market when introducing non-compliance. <p>Firstly the theoretical model investigates the incentives for different farmers to participate in the carbon offsets market as well as incentives for engaging in cheating. The model recognizes farmers heterogeneity with respect to cost differences and examines the economic determinants of farmers non-compliance as well as the consequences of non-compliance on the performance of the carbon-offset market. Results support the standard finding that the extent of producers non-compliance decreases with an increase in the audit probability and/or an increase in the penalty per unit of non-compliance. In addition, the number of producers participating in the carbon offsets market is shown to increase with an increase in the carbon-offset price.<p> The analysis then introduces intermediaries in the market that will take care of trading carbon offsets as well as monitoring producers. The traders role in this study is played by an IOF (investor owned-firm) or a PA (producers association). Within the IOF, the analysis focuses on the monopoly and oligopoly structures. The key role of the traders is to guarantee, based on the amount of monitoring that is undertaken, that the emitters purchase only carbon offsets that actually correspond to sequestered carbon. The analysis then examines three cases for the group that monitors farmers compliance a group owned by for-profit traders, a government-run agency and a group owned by the PA trader. This part of the thesis examines what impact the involvement of the traders in the carbon-offset market has on non-compliance, as well as how the structure of the monitoring group affects non-compliance and the amount of carbon offsets traded in the market. The results of the analysis show that the monitoring groups always undertake sufficient monitoring to ensure that full compliance is achieved thus, while non-compliance is possible, it does not occur in equilibrium. The finding suggests that the formation of a government monitoring agency can potentially increase traded output and lower the price paid by emitters, still these changes are likely to be small, particularly when the trading sector is monopolistic. The overall analysis in this chapter shows that the optimal amount of enforcement, and as a result the cost effectiveness of a carbon-offset market, depends on the nature of the organization that undertakes the enforcement. <p>The next consideration of the thesis is the heterogeneity attributed to the timing of sequestration by different farmers. The analysis focuses on the carbon offsets pooling by considering two structures for the aggregator: a for-profit aggregator and a producers association. Pooling resources enables the farmers to benefit from economies of scale. The pricing schedule used by the aggregator is a two-part tariff. The two-part tariff is used as a way of providing an incentive for the farmers sequestering large amounts of carbon to participate in the pool. The study considers two alternatives for the coefficients that might be used to decide on the amount of carbon offsets to which each farmer will be entitled: default coefficient and custom coefficients. Each situation is modeled in a principal agent framework. <p>The analysis examines how the aggregator will target the monitoring service for different group of farmers. The investigation reveals that, under different scenarios, a PA or a FPA (for-profit aggregator) might lead to the formation of a heterogeneous pool or a homogeneous pool of each type. <p>The last issue investigated in this dissertation is the coexistence of a FPA and a PA in the default coefficient case. The analysis show that both aggregator structures can exist together in the market in the same time if the savings in the monitoring costs made possible by the PA are smaller than the cost of organizing the pool. If this condition is not satisfied the FPA cannot survive in the market and the producers association will dominate. <p>In addition to providing a better understanding of how the carbon-offset market may perform when introducing non-compliance, the results of this study can assist in assessing the cost effectiveness of the carbon-offset market when enforcement is undertaken by different organizations. Furthermore, the last consideration of the pooling option might help in selecting which type of pool a heterogeneous or a homogeneous one might perform better under different alternatives.

Bioretention systems are best management practices (BMPs) that make use of the biogeochemical processes within a forest-type ecosystem to provide at-source stormwater retention and pollutant removal. Laboratory studies and field monitoring have shown great potential for water quantity and quality control through the use of bioretention, but reported nutrient removal has been inconsistent between these systems. In particular, the processes involved in the cycling of phosphorus within bioretention systems are not clearly understood. Some studies report high phosphorus removal from bioretention systems, while phosphorus leaching was observed in other systems. Phosphorus is a macronutrient required by all forms of life. It is also an important water pollutant, as it controls algal growth in most freshwater environments. High phosphorus loadings to these aquatic ecosystems can lead to eutrophication, which has significant ecological, environmental and economical impacts. The Bioretention Phosphorus Removal Model (BPRM), an event-based one-dimensional finite difference model, was developed to simulate phosphorus removal in bioretention systems. The model includes four completely-mixed layers to simulate hydrologic processes as well as both soluble and particulate phosphorus transport in a bioretention system. Model processes include evapotranspiration, infiltration, overflow, exfiltration to native soils, underdrain discharge, soluble phosphorus sorption and vegetative uptake, and particulate phosphorus capture. Monitoring data collected by the Toronto and Region Conservation Authority (TRCA) at a bioretention system installed on Seneca College’s King City campus, in Ontario, Canada, was used to evaluate the performance of BPRM. The model was found to overestimate total underdrain discharge volumes, but total phosphorus concentration and mass predictions were found to be useful for design purposes. BPRM correctly predicted phosphorus leaching from the Seneca College bioretention system for all storm events considered but one. The model can be used by practitioners to evaluate the potential for phosphorus leaching in a bioretention system. A detailed sensitivity analysis revealed that BPRM phosphorus transport predictions are particularly sensitive to the drainage properties of bioretention soils, which highlights the importance of hydrologic transport processes for water quality control in bioretention systems. Modelling results suggested that soluble phosphorus desorption from bioretention soils was responsible for phosphorus leaching from the Seneca College bioretention system. / Thesis (Master, Civil Engineering) -- Queen's University, 2009-09-25 17:00:03.173

Master of Science / Department of Biological and Agricultural Engineering / Aleksey Sheshukov / The global requirements for food and agricultural products have increased enormously in recent years mainly due to increase in global population. More land is brought under human development and cultivation including marginal lands that are susceptible to degradation processes of erosion, waterlogging, and depletion of organic matter. The resulting effects include; deprivation of the roles performed by the environment, high costs of water treatment, and sedimentation of water reservoirs. This study aims at assessment of ephemeral gully (EG) erosion using topographic and hydrologically based models in two paired watersheds in Central Kansas. The effects of best management practices (BMPs) implementation on EG formation, and erosion rates within the watershed are discussed. The topographic index (TI) models used include: slope area model (SA), compound topographic index model (CTI), wetness topographic index model (WTI), slope area power (SA2), kinematic wave model (nLS), and modified kinematic wave model (nLSCSS). EGs predicted by each model threshold were compared with observed EGs obtained through digitization and field reconnaissance. The agreement of thresholds obtained from location and length approaches were compared by means of drainage density concept. Statistical analysis was performed by error matrix for EG location analysis, and root mean square error (RMSE) and Nash–Sutcliffe efficiency (NSE) for EG length analysis. A TIN-based real-time integrated basin simulator (tRIBS) model, a physically-based, distributed hydrological model was coupled with an EG erosion component (Foster and Lane model) to estimate the erosion rates, and effect of installation of BMPs on reduction of EG erosion rates from agricultural fields. The results indicated that TI models could predict EG location with a maximum total accuracy of 70%. The effectiveness of TI models at prediction of EGs is affected by watershed features such as installed structural best management practices, roads, and culverts. The CTI model outperformed all the TI models at prediction of EGs with maximum Kappa and NSE values of 0.32 and 0.55 respectively, and a minimum RMSE value of 0.087 m. Structural BMPs are effective at controlling erosion from croplands, however, the effectiveness of structural BMPs at reduction of sediment loadings from EGs vary depending on surface cover, and BMP geometry.

Monitoring of a regional stormwater management facility, located on the Virginia Tech campus in Blacksburg VA, was conducted in order to assess its efficacy in reducing nonpoint source pollutant losses downstream. The facility design includes both an upper water quality (wet) pond and a lower 100-yr-event quantity (dry) pond. These on-stream ponds capture both baseflow and storm runoff from the southern portion of the Virginia Tech campus and surrounding lands, and release the water back to the unnamed stream shortly above its conjunction with Stroubles Creek, a tributary of the New River. Monitoring sites for flow measurement, water quality sampling, and biotic assessments (habitat evaluation and rapid bioassessment of benthic macroinvertebrates) were located above and below each of the ponds. Both grab samples and automated samples were collected at these stations. Between 1997 and 1999, water quality grab samples included 35 baseflow samples and 22 stormflow samples. The grab samples were analyzed for concentrations of total suspended solids (TSS), metals, bacteria, and nutrients as well as temperature, pH, dissolved oxygen, conductivity, total organic carbon (TOC), and chemical oxygen demand (COD). Automated flow-weighted sampling was initiated in February of 1999 and results are reported through the end of October 1999. Thirty-three storms in 1999 were monitored for flow and various water quality parameters (TSS, TOC, COD, and nutrients). Pollutant loads and pollutant removal estimates were calculated with regard to the wet pond, dry pond, and the combined facility. Two types of pollutant removal efficiencies were calculated: (1) the EMC efficiency, based on pollutant concentrations from individual storms; and (2) the SOL efficiency, based on pollutant loads, to estimate long-term performance over the study period. Benthic macroinvertebrate sampling and habitat assessment were performed in both 1997 and 1999. In addition, a preliminary investigation of pond characteristics was conducted, including measurements of water quality and composition, sediment deposition and composition, and residence time. As a system, the stormwater management facility appears to have minimum impact on improving the downstream water quality. Pollutant concentrations and loads both appear to increase downstream of the facility as compared to upstream, during both storm event and baseflow periods. Monitoring results of the benthic assemblages showed evidence of moderate to high impairment at all sampling locations, and habitat assessments showed evidence of high sedimentation levels within the stream, even after installation of the stormwater management facility. Total suspended solids (TSS) concentration removal efficiency was 10% for the combined wet pond and dry pond system, much lower than the 80 to 90% TSS removal expected for properly functioning stormwater management facilities (Hartigan, 1989). There is some evidence of sedimentation within the ponds because of a slight reduction in sediment-bound constituent export, but the dissolved nutrient constituents had either very low and most often negative (indicating pollutant export) removal efficiencies. Concentrations of metals measured in the stream often exceeded their respective acute and chronic water quality criteria at all sampling locations. Pollutant removal efficiencies measured in the wet pond are atypical of those reported in the literature (Schueler, 1993). Insufficient residence time (two days compared to the optimal two weeks), and wet pond embankment failure are likely the principal causes of the wet pond's inadequate performance and thus, the inadequate performance of the overall facility. TSS removal efficiencies were low in the wet pond (19% for concentrations and 33% for loads) compared to the 80 to 90% expected for similar ponds. Nevertheless, the wet pond reduced the concentrations of several pollutants typically associated with TSS and not likely to be associated with the fill material for the wet pond embankment. Zinc concentrations in sediment cores were highest near the pond inlet, where the majority of sedimentation occurs. During storm events, the following results were noted. Copper and zinc concentrations in 1998 were lower at the pond outlet as compared to the pond inlet, and TOC concentrations and loads were also reduced by the wet pond (13% for concentrations and 12% for loads). However, sedimentation is also expected to remove phosphorusl, and wet pond phosphorus loads were only reduced by 10% and 3% for orthophosphorus and total phosphorus, respectively. Because the wet pond is undersized with respect to the watershed it serves (surface area less than 1% of the watershed area (0.87 ha), as compared to the 3% ratio often recommended for optimal pollutant removal (Athanas, 1988)), higher removal efficiencies were found during baseflow periods. The greatest reductions in baseflow concentrations were for ammonia (67%), nitrate (57%), total nitrogen (54%), and COD (45%). However, the residence time of two days appears to be insufficient to reduce fecal coliform concentrations in the stream, and over 40% of the fecal coliform samples collected exceeded the water quality standard for contact recreation (DEQ-WQS, 1997). Furthermore, the wet pond did not appear to reduce TSS or TOC during baseflow periods. Export of TSS (-29% EMC efficiency) and TOC (-44% EMC efficiency) from the wet pond during baseflow periods is likely due to the wet pond embankment failure as well as pond eutrophication. Eutrophication processes are favored by the water temperature increase as flow passes through the shallow wet pond. The wet pond increased downstream temperatures by approximately 8°C above inflow temperatures during the summer, and to levels above 21°C which cannot be tolerated by sensitive coldwater species (Schueler, 1987). The dry pond did not remove dissolved nutrient constituents or other pollutants during baseflow periods, but there is some evidence of sedimentation within the dry pond during storm events. During storm events, the dry pond was effective in removing TSS, with a concentration removal efficiency of 69% (EMC efficiency) and loading removal efficiency of 43% (SOL Efficiency). Removal of TKN and total phosphorus (36% and 37% respectively for concentrations) within the dry pond is further evidence of sedimentation within the dry pond. The wet pond embankment was built in 1997, and monitoring occurred during a potential stabilization period when evidence of water quality benefits are slow to appear, especially with respect to downstream habitat and aquatic communities. Some benefits which could have been observed more immediately may have been negated or masked by the progressive erosion of the wet pond embankment as a result of a design flaw. Further complicating the results is the appearance; based on observations of extended drawdown time and results from a water budget analysis in the wet pond (where inflow substantially exceeds inflow); that groundwater interacts with the pond in a complicated fashion, possibly including both recharge and discharge. To fully understand the impact of the stormwater management facility on the water quantity and quality within this tributary of Stroubles Creek, monitoring efforts should continue after the wet pond embankment is repaired and is fully operational. If biotic community improvement is desired, the stabilization period could be defined by the time necessary to flush out accumulated sediment within the channel. Monitoring efforts should also expand to include the investigation of the groundwater regime and water level fluctuations within the wet pond. Further measurements of pollutant removal processes and influences upon those processes within the wet pond should also be considered. Last, the influence of the stormwater management facility on downstream flow regimes should be investigated to assess the adequacy of its performance with regard to flow control and prevention of stream channel degradation. / Master of Science

Accurately delivering and precisely timing sprinkler irrigation improves peanut yield and profitability, but there are no data on how to achieve this in the mid-southern USA where furrow-irrigation dominates. This research was conducted to determine if soil water potential could be manipulated through land preparation method, irrigation delivery, and irrigation scheduling. The effects of land preparation method (flat vs bed), furrow-irrigation delivery (every vs every-other furrow), and irrigation scheduling [Food and Agriculture Organization and drainage paper 56 (FAO-56), - 50 kPa, -75 kPa, and -100 kPa] on peanut yield, net returns above irrigation costs, and irrigation water use efficiency were investigated near Stoneville, MS on a Bosket very fine sandy loam. Our data indicate that regardless of land preparation method, peanut yield, net returns above irrigation costs, and irrigation water use efficiency are most often optimized in the mid-southern USA by irrigating every other furrow at a threshold of -50 kPa.

Stream ecosystems are increasingly at risk for thermal impairment as urbanization intensifies, resulting in more heated runoff from impervious cover that is less likely to be cooled naturally. While several best management practices, including bioretention filters, have been able to reduce thermal pollution, success has been limited. The extent of thermal mitigation required to prevent ecological damage is unknown. A calibrated runoff temperature model of a case study watershed in Blacksburg, VA was developed to determine the cumulative treatment volume of bioretention filters required to reduce thermal impacts caused by runoff from development in the watershed to biologically acceptable levels. A future build out scenario of the study watershed was also analyzed. Results from this study established that runoff thermal pollution cannot be fully reduced to goal thresholds during all storms using bioretention filter retrofits. While retrofitting significantly decreased temperatures and heat exports relative to the controls, increasing treatment volumes did not really enhance mitigation. Alternate thermal mitigation methods which actively remove runoff volume should be considered where more thermal mitigation is required. / Master of Science / Stream temperature is a significant ecological, biological, and chemical property affecting the long-term health of streams. However, as development intensifies, stream ecosystems are increasingly at risk of being damaged by thermal pollution, which causes warmer and less stable temperatures that distress aquatic organisms. While several stormwater management methods that reduce runoff-related pollution, known as best management practices (BMPs), were found to also decrease thermal pollution, their success has been limited. Furthermore, the extent of thermal mitigation required to prevent ecological damage is unclear. This study aimed to determine how much treatment by a popular BMP, the bioretention filter, was necessary across a watershed in Blacksburg, VA to adequately reduce thermal pollution to protect stream health. Mitigation impacts were tested on both existing and predicted future development conditions through model simulations. Results from this study established that thermal pollution from runoff cannot be fully reduced to goal thresholds consistently using bioretention filter retrofits. While retrofitting significantly decreased thermal pollution, increasing treatment volume did not considerably enhance mitigation. Results suggested that bioretention filters are not an effective method, and alternate thermal mitigation practices which actively remove runoff volume should instead be considered where intensive reductions in thermal pollution are necessary.