No description available.

No description available.

No description available.

No description available.

No description available.

A comprehensive, distributed parameter, annual, watershed nonpoint source management system (WATNPS) was developed for land management planning. WATNPS simulates annual sediment, nitrogen (chemical and livestock organic), and phosphorus (chemical and livestock organic) yields from nonpoint sources. The system is linked to a GIS platform to reduce the input required by personnel during analysis. WATNPS predicts potential impacts of land management practices on surface water quality. Data were compiled for the Middle Fork Holston River (MFHR) drainage basin, Owl Run and Nomini Creek watersheds in Virginia. WATNPS utilizes annual screening models for the prediction of pollutant yields. Overland delivery ratio, phosphorus yield, and animal waste models were modified for use in the system. In-stream delivery ratio, and pollutant routing procedures were developed as a part of the overall system functionality. Development and calibration of individual in-stream delivery ratio parameters was performed based on single year data from Nomini Creek and Owl Run. A procedure was developed to rank individual watersheds and sites based on predicted pollutant yields during screening. Simulation results and individual watershed characteristics were used during the development of a drainage quality index (DQI). The DQI was developed using statistical analysis to link a water quality indicator to predicted yields and watershed characteristics. The DQI was developed to assess the impact of management within individual watersheds and among watersheds within a drainage basin. WATNPS was validated using observed data. During simulations WATNPS predicted sediment yields within 50% of observed values. Nutrient yields were predicted within a order of magnitude. Simulation of alternative livestock management practices in Owl Run reflected the same trends identified in the observed data. The Hutton Creek simulation was also consistent with water quality observations. A watershed ranking based on the DQI assessment was compared to one provided by local personnel to compare predicted trends to observed watershed conditions. A demonstration of WATNPS selected a single watershed based on watershed rankings. Critical sites were identified during WATNPS site assessment and BMPs were developed. Following BMP implementation the watershed was simulated to determine the impact on sediment, nitrogen, and phosphorus yields. / Ph. D.

Field research was conducted to investigate the impact of vegetative filter strips (VFSs) on surface runoff water quality and to determine if this impact decreases with time. The field research provided information for the development and testing of a model to describe the dynamics and fate of nitrogen (N) in VFSs. The experiment had a completely randomized design, with 3 treatments and 2 replicates per treatment. The treatments were 3 VFS lengths: 0, 4.27, and 8.5 m VFSs. The distribution free Kruskal-Wallis test indicated that the runoff, TSS, NO₃⁻-N, NH₄⁺-N, and TKN yields and concentrations from the 8.5 m VFSs were significantly less (α = 0.05) than the influent values. The TSS and NH₄⁺-N yields and concentrations and the TKN concentration from the 4.27 m VFSs were significantly less than the influent yields and concentrations. The Mann-Kendall test indicated that the yields of TSS, NO₃⁻-N, NH₄⁺-N, and TKN from the filters did not significantly increase from 1992 to 1993 and neither did the FTKN yield nor the FTKN concentration from the beginning to the end of 1993. The mean percentage reductions in influent runoff, TSS, NO₃⁻-N, NH₄⁺-N,, and TKN yields from the 8.5 m filters were 73, 91, 79, 86, and 83%, respectively. The mean percentage reductions in influent TSS, NO₃⁻-N, NH₄⁺-N, and TKN concentrations from the 8.5 m filters were 88, 50, 66, and 75%. The mean percentage reductions in influent runoff, TSS, NO₃⁻-N, NH₄⁺-N, and TKN yields from the 4.27 m filters were 43, 83, 55, 40, and 56%, respectively. The mean percentage reductions in influent TSS, NO₃⁻-N, NH₄⁺-N, and TKN concentrations from the 4.27 m filters were 81, 45, 26, and 41%. Based on the information gathered from the experiment results and the literature, a continuous, long-term, field scale model (Grass Filter Strip Model, GFSM) was developed to describe N transport and dynamics in VFSs. The model was based on GRAPH (GRAssed-strip-PHosphorus), a field scale, event-based model that describes sediment and P transport in runoff. The model simulates sediment, nitrate, sediment-bound and dissolved ammonium, and sediment-bound organic N transport during a runoff event. The model simulates the daily percolation and evapotranspiration and dynamics of nitrate, sediment-bound and dissolved ammonium, and sediment-bound organic N in the filter between runoff events. The model predicts the amount of N and sediment exiting the VFSs, and it can be used to estimate the site specific effectiveness and length of VFSs. The model can also be run for an event to assess the effectiveness of VFSs in reducing nonpoint source pollution loading from a single design storm. The model was validated using runoff, sediment, NO₃⁻ and NH₄⁺ yield field data gathered from April to December, 1993. The model predicted reasonably well (within a factor of 2) the cumulative runoff volume and the yields of TSS. NO₃⁻ and NH₄⁺. The model was most sensitive to the runoff rate, depth of the EDI, soil water storage depth, field capacity, and the steady-state infiltration rates. The model was used to determine the minimum length of VFS required for a 1.3 ha field in Georgia to achieve 75% and 40% sediment and nutrient reductions, respectively, over a 10-year period. The model results indicated that a buffer length of 6.3 m was sufficient to reduce sediment and nitrogen losses by the specified percentages. / Ph. D.

The passage of the Federal Water Pollution Control Act of 1972 required states to develop forestry BMPs to help reduce potential nonpoint source pollution from forest operations. Properly applied forestry best management practices (BMPs) have since been proven to protect water quality from forest operations. This research project reviewed BMP effectiveness studies in the U.S., assessed current state developed and implemented of forestry BMPs, and developed a simple method to estimate potential erosion from forest operations for the Piedmont physiographic region based on previous studies. Eighty-one BMP effectiveness studies were reviewed. The review of past effectiveness studies indicates that water quality protection is increased when BMPs are implemented correctly. These effectiveness studies provide states with valuable information on how their BMP guidelines are achieving the goals defined by the Federal Water Pollution Control Act. Every U.S. state has forestry BMP guidelines. These guidelines may be non-regulatory, quasi-regulatory, or regulatory depending on the state. Twenty states reported implementing non-regulatory BMP guidelines, 19 quasi-regulatory BMP guidelines, and 11 regulatory BMP guidelines. State forestry agencies were reported as being the lead agency responsible for BMP monitoring in 35 states. The national forestry BMP implementation rate was 91% (32 states). However, states did report deficiencies for specific BMP guideline categories. Supplementary to the reviewed BMP effectiveness studies, forest erosion studies in the southeastern U.S. that quantified erosion rates from forest operations were also reviewed. Erosion rates obtained from the literature were reviewed by operation categories (timber harvesting, forest roads, skid trails, log landings, stream crossings, and streamside management zones) and physiographic region (Mountains, Piedmont, Gulf Coastal Plain, and Atlantic Coastal Plain). There were numerous research gaps regarding erosion rates from forest operations for all the regions except the Piedmont region. The Piedmont region was selected for developing a method to estimate potential erosion from forest operations. This erosion estimation method is a quick and potentially useful tool for estimating potential erosion; however, it is based on limited data from the Piedmont region only. The basic method approach might be considered for the other physiographic regions, but further research is needed to fill current knowledge gaps. / Ph. D.

Three watersheds located in Westmoreland County, Virginia were monitored to evaluate effectiveness of forestry best management practices (BMPs) for minimizing hydrologic and water quality impacts associated with timber harvesting. One watershed was clear-cut without implementation of BMPs, one watershed was clear-cut with the implementation of BMPs and the third watershed was left undisturbed as a control. The 27 months of pre-harvest monitoring data and 17 months of post-harvest monitoring data were compared using the paired watershed regression analysis and the minimum detectable change (MDC) statistic. Analysis of the hydrologic data showed that peak discharge rates were not impacted by harvesting, regardless of whether BMPs were implemented. Harvesting with or without the implementation of BMPs resulted in no statistically significant change in stormflow volume. BMP implementation was found to be effective in minimizing harvesting impacts on stormflow total suspended solids (TSS), ammonia, total Kjeldahl nitrogen (TKN), total nitrogen (TN), sediment-bound nitrogen and total phosphorous (TP) concentrations and total flow TSS and TP concentrations. BMP implementation was also effective in minimizing harvesting impacts on stormflow TSS, TKN, sediment-bound nitrogen, TP and sediment-bound phosphorous loadings and total ammonia loading. The BMPs were not effective in reducing nitrate concentrations and loadings. The BROOK90 forest hydrology model was used to predict the site hydrology. Model predictions compared favorably with streamflow measurements from watersheds QN3 and QN4 until the time of harvest, but did not predict streamflows as accurately for the control watershed, QN5. / Master of Science

Dairy producers across the country are evaluating the effectiveness of management intensive grazing (MIG) systems as a means of reducing the economic pressures of confinement feeding and manure handling. Systems using MIG have been promoted as an environmentally safer way of managing nutrient balance on Center. However, little research has been conducted to evaluate how these systems affect phosphorus (P) loss from the Center through runoff and forage removal. The goal of this study was to investigate the effects of forage type and manure density on P levels in runoff from release plots that simulated a MIG dairy system. Two forage treatments were planted on runoff release plots and applied with three manure density treatments and four replications of each combination for a total of 24 plots. Orchardgrass (Dactylis glomerata) and a broad-leafed forage treatment consisting of buckhorn plantain (Plantago lanceolata), red clover (Trifolium pratense), and alfalfa (Medicago sativa) were planted on the runoff release plots in early spring. Manure densities with no manure (control), a density simulating a low stocking density (low), and a density simulating high stocking density (high) were applied to plots during grazing simulations. Six rainfall simulations were conducted over the season simulating grazing conditions when forage was removed and re-growth conditions when forage had reached its target re-growth height before re-grazing occurred. Thirty minutes of runoff was collected from the runoff release plots to determine first flush phosphorus losses from the various treatments. Mass losses of total phosphorus (TP) for manure treatments in series 1 were significant due to plot installation disturbance. No significant effect for ortho-phosphorus (ortho-P), particulate phosphorus (PP) or TP concentration or mass losses were observed for other simulation series. Significantly higher mass losses were observed in series 1 for both forage treatments, again due to installation disturbance. Seasonal mass losses for TP were significantly lower for the orchardgrass treatment. Forage mass removal over the season increased as the stands established. Orchardgrass treatments appeared to control P losses earlier in the season, while broadleaf treatments observed a steady increase in ortho-P losses up to series 5. Both mass and concentration losses of TP were controlled earlier in the season by orchardgrass, while PP showed no significant mass or concentration loss effects. / Master of Science