Floating treatment wetlands (FTWs) are an innovative best management practice that can enhance the performance of traditional retention ponds by increasing removal of the nutrients nitrogen (N) and phosphorous (P). FTWs consist of floating rafts on which wetland plants are planted, allowing the roots to be submerged below the water surface while the shoots remain above. A growing body of research has documented FTW performance with regard to urban runoff treatment, however evaluation of FTW effectiveness for treatment of agricultural runoff has received less attention. Due to high fertilization and irrigation rates, commercial nursery runoff contains much higher concentrations of N and P than runoff from urban areas. We conducted this study over two growing seasons (2015 and 2016) to assess the effectiveness of FTWs for use in commercial nursery retention ponds. In the first study we used two different nutrient concentrations, one to simulate nursery runoff (17.1 mg∙L-1 TN and 2.61 mg∙L-1 TP) and one to simulate concentrations that fall between urban and nursery runoff (5.22 mg∙L-1 TN and 0.52 mg∙L-1 TP). Four treatments were used: 1) Pontederia cordata planted in cups supported by a Beemat, 2) Juncus effusus planted in cups supported by a Beemat, 3) a Beemat with no plants, and 4) no treatment (open-water). Performance was evaluated based on a 7-day hydraulic retention time (HRT). Pontederia cordata removed between 90.3% and 92.4% of total phosphorus (TP) and 84.3% and 88.9% total nitrogen (TN), depending on initial loads. These reductions were significantly more than other treatments at both high and low nutrient loading rates. Juncus effusus performed better than the control treatments for TP removal at low nutrient concentrations, but did not perform any better than the control at higher nutrient loads. In the second study, conducted in 2016, we evaluated different plant species over two 8-week trials using simulated nursery runoff. We used five monoculture FTWs with the following species: Agrostis alba, Canna ×generalis, Carex stricta, Iris ensata, and Panicum virgatum. Additionally, two treatments were created from mixed species plantings and the final treatment consisted of an open water control mesocosm. Nutrient removal performance was evaluated over a 7-day HRT. P removal (phosphate-P) by FTW treatments ranged from 26.1% to 64.7% for trial 1 and 26.8% to 63.2% for trial 2. Trial 1 N removal (sum of ammonium-N, nitrate-N, and nitrite-N) efficiencies ranged from 38.9% to 82.4%, and trial 2 ranged from 12.9% to 59.6%. Panicum virgatum removed significantly more N and P than the control and any other FTW treatment in the second study. Both studies indicated, depending upon plant species, that FTWs can effectively remove nitrogen and phosphorous from urban and commercial nursery retention ponds. / Master of Science

Intensively managed forests of the Southern United States are among the most important sources of wood fiber and timber in this country. There is a great deal of concern that disturbances associated with trafficking by heavy machinery might diminish long-term soil-site productivity. However, determining the effect of harvesting disturbance and silvicultural treatments on the long-term productivity of pine plantations is difficult because, in addition to harvesting effects, growth distributions are affected by changes in climate, silviculture, and genetics. The primary objectives of this study were to determine (1) whether logging disturbances under operationally realistic circumstances affect soil quality, hydrologic function, and loblolly pine (Pinus taeda L.) productivity on wet pine flats, and (2) whether intensive forest management practices mitigate disturbance effects if they exist. Three 20-ha loblolly pine plantations located on wet pine flats in South Carolina were subjected to combinations of wet- and dry-weather harvesting and mechanical site preparations. Changes in soil-site productivity after five years were evaluated using a new rank method. The key advantage of the rank change method is that it is largely independent of the confounding factors (e.g. genetics, silvicultural practices, and climate) that affect comparisons of tree growth and soil quality between growth cycles. After five years, loblolly pine site indexes (base age 25) ranged between 13 and 33 m, and production ranged between 0.5 and 95 Mg ha-1. Soil bulk densities increased from 1.15 to as high as 1.44 g cm-3 after harvesting; by age 7 years it had decreased to approximately 1.25 g cm-3. At the sub-stand scale (0.008 ha), visually assessed soil physical and harvesting residue disturbances had little influence on relative changes in soil-site productivity after five years. Factors that specifically reflect site drainage were the most influential on changes in productivity. At the operational scale (3.3 ha), there were no differences between wet- and dry- harvested sites as long as bedding was applied as a site treatment. These results indicate that when standard site preparation is employed, fertile, wet pine flats such as these are resilient in that they recover from severe, but operationally realistic, harvesting disturbances. / Ph. D.

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

Thesis (M.Ing.)--Stellenbosch University, 2000. / ENGLISH ABSTRACT: The objective of this research has been to compare nonpoint sources assessment techniques for simulating phosphorous production in rural catchments which have a variety ofland use types. Four nonpoint source assessment techniques capable of simulating phosphorous production, operating at different spatial and temporal resolutions, were selected after an intensive literature review. The model selection criteria included the capability to simulate phosphorous production, the need for the study to cover a range of spatial and temporal resolutions, model data requirements, model affordability and availability in South Africa. The models selected using these criteria are the Phosphorous Export Model (PEM) (Weddepohl & Meyer, 1992), Impoundment and River Management and Planning Assessment Tool for Water Quality Simulation Model (IMPAQ) (DWAF,1995), the Hydrological Simulation Program Fortran (HSPF) (Bricknell,1993) and the Agricultural Catchments Research Unit Model (ACRU) (Smithers and Caldecott, 1994). Four ofthe study catchments were selected within the Berg River basin in the Western Cape and the remaining four were selected within the Amatole catchments in the Eastern Cape. The four subcatchments in the Berg River basin are the Twenty-Four Rivers, Leeu River, Kompanjies River and Doring River catchments and the four in the Amatole catchments are the Upper Buffalo, Cwencwe, Yellowwoods and Gqunube River catchments. The range of land use/cover types comprises: Western Cape catchments : wheat, grapes, natural vegetation and forestry Eastern Cape catchments : natural vegetation and forestry The PEM and IMPAQ models were applied reasonably successfully to all the catchments to simulate phosphorous production, with the observed flow as the input. The HSPF model could not successfully be applied to the catchments to simulate both the catchment hydrology and phosphorous production. Hence, the investigation into HSPF was abandoned, and in its place, the ACRU daily phosphorous yield model was incorporated at a fairly late stage in the research. ACRU was applied to only the Western Cape catchments. The estimated parameters for different land use types were compared to investigate the potential for parameter transfer in space and time. Both the PEM and IMP AQ models showed promise that land use parameters could be transferred in time for catchments located in the Western Cape catchments, but did not show promise for catchments located in the Eastern Cape. The IMPAQ model showed promise that land use parameters could be transferred in space for catchments located in the Eastern Cape, but did not perform as well in the Western Cape catchments. The PEM model showed promise that land use parameters could be transferred in space for catchments located in the Western Cape, but did not perform as well in the Eastern Cape. Since the ACRU phosphorous yield model was included at a late stage of the research, the potential for land use parameter transfer in space and time could not investigated. The model results were verified at the relevant flow and water quality gauging stations. The ACRU phosphorous model verification results showed promise for catchments located in humid parts of the Berg River basin, but did not perform as well in the catchment located in the semi-arid part. RECOMMENDATIONS FOR FURTHER RESEARCH: I. Intensive research should be undertaken to develop a database ofland use parameters/ export coefficients related to phosphorous production (and other non-conservative constituents) in South African catchments. Availability of these parameters would make phosphorous modelling much easier. HSPF should be configured and calibrated, more especially its water quality component, for catchments with hourly rainfall and rainfall stations located within/on the catchment boundaries, to investigate its performance under South African conditions. Given the complexity of the HSPF algorithms and the time required to familiarise oneself with the model, it is recommended that such an investigation be undertaken which is not inclusive of any other models. The spatial resolution ofPEM is extremely coarse, and should be improved to allow the user to partition the total flow in the catchment according to contributions from the variety ofland use types and to estimate soluble and particulate phosphorous parameters for each land use type. A study should be undertaken to investigate the potential for the ACRU phosphorous yield model parameter transfer in time and space. Sampling frequency of water quality data in South Africa should be improved, because it is difficult to assess the performance of the calibrated water quality models, more especially phosphorous export models, due to a lack of continuous data sets. Rainfall data collection in gauged catchments, more especially Western Cape catchments (e.g. Twenty-Four Rivers, Leeu, Kompanjies and the Doring River catchments), should be improved. There should be at least one rainfall gauging station located within the catchment boundaries. This would contribute towards achieving reasonable hydrological calibration or verification. Since runoff is the driving factor for water quality components, improved hydrological calibration/verification would result in reasonable water quality calibration/verification. / AFRIKAANSE OPSOMMING: Die doel van die navorsing was om die simulering van fosfaat produksie in landelike gebiede, wat 'n verskeidenheid grondgebruike het, met behulp van nie-punt bron evaluerings tegnieke te evulaeer. Vier nie-punt bron evaluerings tegnieke, met die vermoë om fosfaat produksie op verskillende ruimtelike en tyds resolusies te simuleer, is gekies na 'n intensiewe ondersoek van beskikbare literatuur. Die kriteria vir die keuse van die model het ingesluit die vermoë om fosfaat produksie te simuleer, die behoefte vir die studie om 'n reeks van ruimtelike en tyds resolusies te simuleer, model data vereistes, model bekostigbaarheid en beskikbaarheid in Suid Afrika. Die gekose modelle, gebaseer op bogemelde kriteria, was die PEM, IMPAQ, HSPF en ACRU modelle. Vier van die opvanggebiede gebruik in die studie, was in die Bergrivier bekken in die Wes-Kaap en vier was in die Amatole opvanggebiede in die Oos-Kaap. Die vier opvanggebiede in die Bergrivier bekken is die Vier-en- Twentigriviere, Leeurivier, Kompanjiesrivier en die Doringrivier en die vier opvanggebiede in die Amatole opvanggebiede is die Bo-Buffels, Cwencwe, Yellowwoods, en die Gunubierivier opvanggebiede. Grondgebruik beslaan die volgende: Wes-Kaap opvanggebiede : koring, druiwe, natuurlike weiding en plantasies. Oos-Kaap : natuurlike plantegroei en plantasies Die PEM en IMPAQ modelle is met redelike sukses in al die opvanggebiede gebruik vir die simulasie van fosfaat produksie, met die waargenome vloei as invoer. Die HSPF model kan nie met enige sukses gebruik word om beide die opvanggebied hidrologie en fosfaat produksie, te simuleer nie. Die HSPF model is dus uitgeskakel en in 'n redelike laat stadium van die studie met die ACRU daaglikse fosfaat leweringsmodel vervang. Die ACRU model is net op die Wes-Kaap opvanggebiede toegepas. Die beraamde parameters vir die verskillende grondgebruik tipes is vergelyk om die potensiaal vir parameter oordrag in ruimte en tyd te ondersoek. Beide die PEM en IMPAQ modelle het belowend vertoon ten opsigte van die oordrag van grondgebruik parameters in tyd vir opvanggebiede in die Wes- Kaap, maar het geensins belowend vertoon vir die Oos-Kaap opvanggebiede nie. Die IMPAQ model het belowend vertoon ten opsigte van die ruimtelike oordrag van grondgebruik parameters vir die Oos-Kaap opvanggebiede, maar het nie so goed vertoon in die Wes-Kaap opvanggebiede nie. Die PEM model het belowend vertoon ten opsigte van die ruimtelike oordrag dat grondgebruikte parameters in die Wes-Kaap opvanggebiede is, maar het nie so goed in die Oos-Kaap opvanggebiede vertoon nie. Aangesien die ACRU fosfaat leweringsmodel op 'n laat stadium van die navorsing ingesluit is, kan die potensiaal vir die oordrag van grondgebruik parameters in ruimte en tyd nie ondersoek word nie. Die model resultate is by die toepaslike vloei en waterkwaliteit meetstasies geverifiëer Die resultate van die ACRU fosfaat model verifikasie het belowend vertoon vir opvangebiede in die humiede gedeeltes van die Bergrivier bekken, maar het nie so goed vertoon in die semi-droeë deel van die opvangebied nie. AANBEVELINGS VIR VERDERE NAVORSING : Y4 Intensiewe navorsing moet onderneem word ten einde in 'n databasis van grondgebruik parameters/oordrag koëffisiente met betrekking tot fosfaat produksie (en ander niekonserwatiewe bestandelle ) in Suid Afrikaanse opvanggebiede op te bou. Beskikbaarheid van hierdie parameters sal fosfaat modellering vergemaklik. Die HSPF model moet opgestel en gekalibreer word, meer spesifiek ten opsigte van die waterkwaliteit komponent, vir opvanggebiede met uurlikse reënval en reënvalstasies binne of op die opvanggebied grense, om die model se vertoning onder Suid Afrikaanse omstandighede te ondersoek. Gegewe die kompleksiteit van die HSPF algoritmes en tyd benodig om met model vertroud te raak, word dit aanbeveel dat so 'n ondersoek onderneem word met uitsluiting van die ander modelle. Die ruimtelike resolusie van die PEM model is uitermatig grof, en behoort verbeter te word ten einde die gebruiker toe te laat om die totale vloei in die opvanggebied in ooreenstemming met die bydraes van die onderskeie grondgebruik tipes te verdeel en om oplosbare en partikulere fosfaat parameters vir elke grondgebruik tipe te beraam. 'n Studie om die potensiaal vir die ruimtelike en tydsoordrag van die ACRU fosfaat leweringsmodel parameters te ondersoek, moet onderneem word. Die frekwensie van waterkwaliteit monitering in Suid Afrika moet verbeter word, aangesien dit moelik is om, weens 'n gebrek aan deurlopend waargenome data, die vertoning van gekalibreerde waterkwaliteit modelle te ondersoek, meer spesifiek nog fosfaat uitvoer modelle. Reënval inligting versameling in gemete opvanggebied, meer spesifiek die Wes-Kaap opvanggebiede (bv.Vier-en-Twintigriviere, Leeu, Kompanjies en Doringrivier opvanggebiede), behoort verbeter te word. Daar behoort ten minste een reënval stasie binne die opvanggebied grense te wees. Dit sal bydra tot die bereiking van redelike hidrologiese kalibrasie ofverifikasie. Aangesien afloop die dryfveer van die waterkwaliteit komponente is, sal verbeterde hidrologiese kalibrasie/verifikasie lei tot redelike waterkwaliteit kalibrasie/verifikasie.

In 2011, the Deep River Portage-Burns Waterway Watershed was identified as a priority in the Northwest Indiana watershed management framework by the Northwester Indiana Regional Planning Committee. 319 grant cost-share programs were initiated in effort of maintaining and restoring the health of Deep River Portage-Burns Waterway Watershed. A watershed management plans have been developed for this watershed which proposed the implementation of vegetated filter strips (VFS) as an option. In this thesis work, the effectiveness of VFS as a best management practice (BMP) for the Deep River system was evaluated using a hydrological model scheme. <div><br></div><div>In this research, a Nonpoint Source Pollution and Erosion Comparison Tool (NSPECT) model and a Soil Water Assessment Tool (SWAT) model were constructed with required watershed characteristic data and climate data. The initial hydrologic and nutrient parameters of the SWAT model were further calibrated using SWAT Calibration and Uncertainty Programs (SWAT_CUP) with historical flow and nutrient data in a two-stage calibration process. The calibrated parameters were validated to accurately simulate the field condition and preserved in SWAT model for effectiveness analysis of BMP implementations. </div><div><br></div><div>To evaluate the effectiveness of VFS as a BMP, four different scenarios of VFS implementations along the Turkey Creek was simulated with the calibrated SWAT model. With the implementation of VFS in the tributary subbasin of Turkey Creek, the annual total phosphorus (TP) of the VFS implemented subbasin was reduced by 1.60% to 78.95% and the annual TP of downstream subbasins were reduced by 0.09% to 55.42%. Daily percentage of TP reductions ranged from 0% to 90.3% on the VFS implemented subbasin. Annual TP reductions of the four scenarios ranged from 28.11 kg to 465.01 kg.<br></div>

Submitted by Silvana Teresinha Dornelles Studzinski (sstudzinski) on 2016-12-22T14:40:54Z No. of bitstreams: 1 Onésima Aguiar Campos Barreto_.pdf: 819320 bytes, checksum: 77032227ee24042f8cd627cc2eef5be9 (MD5) / Made available in DSpace on 2016-12-22T14:40:54Z (GMT). No. of bitstreams: 1 Onésima Aguiar Campos Barreto_.pdf: 819320 bytes, checksum: 77032227ee24042f8cd627cc2eef5be9 (MD5) Previous issue date: 2016-07-25 / Nenhuma / A indústria da construção civil exerce uma grande contribuição para o desenvolvimento da economia dos países, principalmente se considerada a quantidade de empregos gerados e a influência direta em todos os setores que produzem insumos, equipamentos e serviços para a utilização no seu processo produtivo. Apesar desse grande destaque da indústria da construção civil brasileira na economia nacional, o setor é grande consumidor de recursos naturais, pois as obras utilizam grande quantidade e variedade de materiais de construção que, na maioria das vezes, por falta de planejamento, são desperdiçados e transformados em Resíduos da Construção Civil (RCC). O crescimento progressivo dos RCC tem ocorrido juntamente com o aumento da população, e traz consigo problemas ambientais em virtude do crescimento da construção civil, que no intuito de atender as expectativas da sociedade, caminham lado a lado com este crescimento. O município de Palmas/TO nos últimos anos vem passando por um processo acelerado de verticalização, acompanhado da geração de uma grande quantidade de RCC. No que tange às disposições desses resíduos no município e os impactos que eles provocam, esta pesquisa propôs diagnosticar a atual situação, baseado em um framework teórico de boas práticas e manejo, e da classificação e quantificação dos RCC gerados pelo período de um ano. Estas informações subsidiaram a elaboração de um manual de gerenciamento baseado em boas práticas de gestão e manejo. O método de pesquisa caracteriza-se como abordagem qualitativa, de natureza aplicada, com objetivos, exploratório e descritivo, sendo utilizados como método de trabalho, a pesquisa bibliográfica, documental e estudo de caso. Os dados foram coletados através da aplicação de questionários abertos e entrevistas com roteiro previamente definido. Os principais achados são: a falta de fiscalização e ineficiência da administração pública municipal; e a falta de gerenciamento ambientalmente correto pelas empresas construtoras, que as impedem de terem ganhos financeiros com a reutilização e reciclagem dos RCC. As recomendações para trabalhos futuros tratam-se da investigação da eficácia das certificações ISO 9001 e P-BQPH nas empresas construtoras, em especial no município de Palmas; a viabilidade do ponto de vista técnico e ambiental da adoção do manual de boas práticas proposto, para que se comprove sua eficácia quanto ao gerenciamento dos RCC, e por fim, a aplicação do framework teórico em estudos de campo. / The construction industry has a significant contribution to the countries’ economy development, especially if considered the created jobs amount and the direct influence across the sectors that produce raw materials, equipment and services for use in its production process. In spite of this major highlight of Brazilian civil construction industry in the national economy, the sector is large consumer of natural resources, since the construction uses building materials in large quantity and variety , most often, for lack of planning, are wasted and turned into Construction Waste (CW) The progressive growth of the CW has been in conjunction with an increase in population, and bring with them environmental problems arising from construction growth that in order to attend the expectations of society go hand in hand with this development. the city of Palmas/TO in the past years has experienced an accelerated process of verticalization, accompanied by the generation of a large amount of CW. Regarding to the provisions of this waste in the city and the impacts they cause, this research proposed to diagnose the current situation, based on a theoretical framework of good practices and managing, and classification and quantification of CW generated for a period of one year. This information supported the development of a management guide based on best management and handling practices. The research method is characterized as a qualitative approach, with applied nature, exploratory and descriptive objectives, being used as a working method, bibliographical, documentary research and case study. Data were collected through the application of open questionnaires and interviews with pre-defined script. The main findings are: the lack of supervision and inefficiency of the municipal government; and the lack of environmentally proper management for construction companies, preventing them from having the financial gains from the reuse and recycling of CW. Recommendations for future studies are: the investigation of the effectiveness of ISO 9001 and PBQP-H certifications in construction companies, especially in the city of Palmas; the viability of the technical and environmental point of view of the adoption of the proposed the best management guide, in order to prove its effectiveness as the management of CW, and finally, the application of theoretical framework on field studies.

Agricultural runoff is one of largest contributors of phosphorus (P), nitrogen (N), and sediment affecting freshwater systems in watersheds across the Northeastern U.S., including the Lake Champlain Basin in Vermont. Agricultural cropping systems, such as corn silage and haylands, used for dairy feed production have been shown to impact watershed hydrology and water quality. Agricultural best management practices (BMPs) have the potential to decrease runoff volumes and flow rates and the associated export of nutrients and sediment from agricultural fields. Many states in the Northeastern U.S., including Vermont, are beginning to require farmers to implement water quality BMPs and further improve risk evaluation of export of P in runoff using evolving P site assessment tools, such as the Phosphorus Index (P-Index). Quantifying the effects of BMPs on hydrologic and nutrient exports from fields is critical for informing site assessment tools that aid in the development of nutrient management plans and to help design agroecosystems that do not degrade water quality. However, there is a lack of data on the effects of BMPs on edge-of-field hydrologic and nutrient fluxes, especially in cold-climate regions with snow-melt induced runoff events. This thesis consists of four chapters, Chapter 1 is a comprehensive literature review on agricultural hydrology and water quality, BMP effectiveness, and P site assessment tools. Chapters 2 and 3 address research objectives related to the evaluation of BMP and P site assessment tool effectiveness. Chapter 4 is a summary of the conclusions drawn from the work done in Chapters 2 and 3, and suggestions for future work. Chapter 2 evaluates the effects of soil aeration prior to manure application on edge-of-field hydrology, water quality, and P fluxes in haylands with clay soils during both precipitation and snow-melt induced runoff events. Edge-of-field water quality monitoring techniques and passive-capillary lysimeter systems were used to continuously measure the losses of surface runoff, subsurface leachate, and the associated export of nutrients (total phosphorus, total dissolved phosphorus, total nitrogen, and total dissolved nitrogen) and total suspended solids resulting from runoff events year-round from 2012 to 2018. Annual P fluxes in the form of vegetative uptake and removal, manure additions, and soil test P were also recorded. Results from this study indicated that soil aeration had the potential to reduce nutrient and sediment exports from haylands with poorly-drained, high runoff producing soils in the Northeastern U.S. where winter freeze-thaw conditions exist. However, potential increases in surface and subsurface hydrologic flows can accompany these reductions; these implications should be considered before implementation. Chapter 3 identifies potential P-Index improvements through the representation of topographic controls on phosphorus (P) transport by comparing results from the Vermont P-Index (VT P-Index) and a more complex process-based model, TopoSWAT, across topographic regions in a small agricultural watershed (360 ha) in the Lake Champlain Basin. Scenarios of varying P management strategies were modeled for corn silage production fields with poorly-drained soils and rolling topography. Modeled outputs of P risk assessments and edge-of-field dissolved and particulate P losses were compared. Results from this study suggest that the VT P-Index could improve its ability to support farm nutrient management planning and other P-based management decisions by incorporating topographic controls of runoff production into its estimation of P transport.

In coastal urban regions, underground stormwater treatment units are suitable infrastructure options because they take less space where premium land is expensive. Even then, they should be accessible and ideally small enough to fit into existing stormwater networks. Since 2003, the City of Tampa and Florida’s Department of Transportation (FDOT) have installed 47 baffle boxes into the city’s stormwater pipe networks. Baffle boxes are underground stormwater treatment structures designed to capture sediments and floating debris. Since their deployment, many challenges regarding their practical sediment capturing performance was raised by the city. The objective of this research was to evaluate the effects of rainfall, land use, and maintenance on the sediment trapping efficiency of the baffle boxes and identify solutions to enhance their performance. This was addressed through site visits, sediment accumulation measurements and analysis of historical and field data. The results of these measurements and analysis were then compared to rainfall intensity, catchment characteristics, size and type of the units. During the preliminary site visits and sediment measurements it was observed that most of the units located in the south of Tampa were inundated by backflows from Tampa Bay. Survey information collected from inspection crew members also showed that resuspension of trapped sediments frequently occurs in these units. Concerning operation and maintenance (O&M), it was indicated that units mounted with screens are costly and difficult to clean-out. Additionally, it was found that 80% of the units have very small trap inlets and lack the baffle structures needed to slow down and settle sediments. Historical sediment measurements and O&M practices were analyzed to calculate the overall performance of the units. The analysis of the data determined the sediments captured, the resuspension rate, and yearly cost of maintenance for different types of baffle boxes. Rainfall intensity and land use and land cover (LULC) data for each catchment of the units was correlated to the performance of the units. The LULC data used impervious fraction and tree canopy area of the catchments to project sediment and leaf matter accumulation within the units. This research study found that total daily rainfall intensity is a good predictor of sediment accumulation. Cleanout crews can use this relationship to conduct their work efficiently and to promptly react to occurring rainfall events. Thus, the prediction of sediments accumulated from rainfall events and the coordination of clean-out trucks can optimize O&M practices. It was also determined that large-sized (24-40 in) units and those with three chambers (baffles) perform better at trapping sediments. Thus, installing baffles in units within the large-sized ones can enhance their performance. The study also found that baffle boxes mounted with screens can individually take up to eight hours to cleanup which makes them costly and difficult. This can be detrimental for municipalities to follow up on their O&M practices effectively. Therefore, to alleviate the clean out complexity and reduce maintenance expenditures complementary practices such as bag filters need to be explored and implemented for trials

This research assessed the seasonal effects of contrasting tillage and crop rotation systems on soil ammonia oxidizing bacteria (AOB) and archaea (AOA). Four different cropping systems under till and no-till were analyzed in a 30 year-old agricultural field trial. Samples were collected during the 2010 growing season at times corresponding with agronomic events. Nucleic acids were preserved in the field and subsequently analyzed by quantitative real-time polymerase chain reactions (qPCR). Tillage decreased AOB activity and abundance in the plow layer (0-15 cm) immediately after fall moldboard plow events, but observed AOB dynamics at other times suggest tillage had a long-term distribution effect across depth (0-30 cm). AOA abundance was significantly greater in no-till plots at all times indicating tillage had longer-term effects on these communities. Crop rotation had minimal effect on AOB and AOA, but there was a noted yield advantage for corn following wheat, regardless of tillage treatment. / OMAFRA Highly Qualified Personnel Program, NSERC