Showing papers on "Nonpoint source pollution published in 1998"
TL;DR: A conceptual, continuous time model called SWAT (Soil and Water Assessment Tool) was developed to assist water resource managers in assessing the impact of management on water supplies and nonpoint source pollution in watersheds and large river basins as discussed by the authors.
Abstract: A conceptual, continuous time model called SWAT (Soil and Water Assessment Tool) was developed to assist water resource managers in assessing the impact of management on water supplies and nonpoint source pollution in watersheds and large river basins. The model is currently being utilized in several large area projects by EPA, NOAA, NRCS and others to estimate the off-site impacts of climate and management on water use, nonpoint source loadings, and pesticide contamination. Model development, operation, limitations, and assumptions are discussed and components of the model are described. In Part II, a GIS input/output interface is presented along with model validation on three basins within the Upper Trinity basin in Texas.
6,674 citations
TL;DR: In this article, a review of the available scientific information, they are confident that nonpoint pollution of surface waters with P and N could be reduced by reducing surplus nutrient flows in agricultural systems and processes, reducing agricultural and urban runoff by diverse methods, and reducing N emissions from fossil fuel burning, but rates of recovery are highly variable among water bodies.
Abstract: Agriculture and urban activities are major sources of phosphorus and nitrogen to aquatic ecosystems. Atmospheric deposition further contributes as a source of N. These nonpoint inputs of nutrients are difficult to measure and regulate because they derive from activities dispersed over wide areas of land and are variable in time due to effects of weather. In aquatic ecosystems, these nutrients cause diverse problems such as toxic algal blooms, loss of oxygen, fish kills, loss of biodiversity (including species important for commerce and recreation), loss of aquatic plant beds and coral reefs, and other problems. Nutrient enrichment seriously degrades aquatic ecosystems and impairs the use of water for drinking, industry, agriculture, recreation, and other purposes.
Based on our review of the scientific literature, we are certain that (1) eutrophication is a widespread problem in rivers, lakes, estuaries, and coastal oceans, caused by overenrichment with P and N; (2) nonpoint pollution, a major source of P and N to surface waters of the United States, results primarily from agriculture and urban activity, including industry; (3) inputs of P and N to agriculture in the form of fertilizers exceed outputs in produce in the United States and many other nations; (4) nutrient flows to aquatic ecosystems are directly related to animal stocking densities, and under high livestock densities, manure production exceeds the needs of crops to which the manure is applied; (5) excess fertilization and manure production cause a P surplus to accumulate in soil, some of which is transported to aquatic ecosystems; and (6) excess fertilization and manure production on agricultural lands create surplus N, which is mobile in many soils and often leaches to downstream aquatic ecosystems, and which can also volatilize to the atmosphere, redepositing elsewhere and eventually reaching aquatic ecosystems.
If current practices continue, nonpoint pollution of surface waters is virtually certain to increase in the future. Such an outcome is not inevitable, however, because a number of technologies, land use practices, and conservation measures are capable of decreasing the flow of nonpoint P and N into surface waters.
From our review of the available scientific information, we are confident that: (1) nonpoint pollution of surface waters with P and N could be reduced by reducing surplus nutrient flows in agricultural systems and processes, reducing agricultural and urban runoff by diverse methods, and reducing N emissions from fossil fuel burning; and (2) eutrophication can be reversed by decreasing input rates of P and N to aquatic ecosystems, but rates of recovery are highly variable among water bodies. Often, the eutrophic state is persistent, and recovery is slow.
5,662 citations
TL;DR: The importance of agricultural sources to nonpoint source pollution of surface waters has been an environmental issue for decades because of the well-known role of P in eutrophication as mentioned in this paper.
Abstract: The importance of P originating from agricultural sources to the nonpoint source pollution of surface waters has been an environmental issue for decades because of the well-known role of P in eutrophication. Most previous research and nonpoint source control efforts have emphasized P losses by surface erosion and runoff because of the relative immobility of P in soils. Consequently, P leaching and losses of P via subsurface runoff have rarely heen considered important pathways for the movement of agricultural P to surface waters. However, there are situations where environmentally significant export of P in agricultural drainage has occurred (e.g., deep sandy soils, high organic matter soils, or soils with high soil P concentrations from long-term overfertilization andlor excessive use of organic wastes). In this paper we review research on P leaching and export in subsurface runoff and present overviews of ongoing research in the Atlantic Coastal Plain of the USA (Delaware), the midwestern USA (Indiana), and eastern Canada (Quehec). Our objectives are to illustrate the importance of agricultural drainage to nonpoint source pollution of surface waters and to emphasize the need for soil and water conservation practices that can minimize P losses in suhsurface runoff.
1,101 citations
TL;DR: Water quality of highway runoff in the Austin, Texas, area was determined by monitoring runoff at three locations on the MoPac Expressway as mentioned in this paper, where a grassy swale at one site was effective in reducing the concentrations of most constituents in runoff.
Abstract: Water quality of highway runoff in the Austin, Texas, area was determined by monitoring runoff at three locations on the MoPac Expressway. Daily traffic volumes, surrounding land uses, and highway drainage system types were different at each site. The concentrations of constituents in runoff at all sites were similar to median values compiled in a nationwide study of highway runoff quality. A grassy swale at one site was effective in reducing the concentrations of most constituents in runoff. The lower runoff coefficient at this site is attributable to infiltration of runoff into the grassy swale. The pollutant loads discharged from the pipe draining the swale were lower than those observed at the sites where runoff drained directly from the pavement. A first flush effect (i.e., higher pollutant concentrations at the beginning of an event) was evident during selected events, but was generally limited to a small volume. The overall effect was negligible when all monitored events were considered.
359 citations
TL;DR: In this article, three highway segments typical of urban, semi-urban, and rural settings in the Piedmont region of North Carolina were monitored to characterize the respective runoff constituent concentrations and pollutant discharge or export loadings.
Abstract: Three highway segments typical of urban, semiurban, and rural settings in the Piedmont region of North Carolina were monitored to characterize the respective runoff constituent concentrations and pollutant discharge or export loadings. Runoff from the impervious bridge deck (Site I) carried total suspended solids (TSSs) concentrations and loadings that are relatively higher than typical urban highways, whereas nitrogen and phosphorus loadings are similar to agricultural runoff. Site II included a pervious roadside shoulder with traffic volume equal to that of Site I. Site III was a nonurban highway having lower traffic counts and imperviousness due to the presence of a roadside median. The existing roadside shoulder and median appeared to attain at least 10–20% hydrologic attenuation of peak runoff discharges, more than 60% reduction of event mean concentration of TSSs, and attenuation of the first-flush concentrations for most pollutant constituents. Bulk precipitation data collected at the bridge deck s...
283 citations
TL;DR: The Clean Water Act defines concentrated animal feeding operations as point sources of pollution that are required to obtain permits to discharge into waters of the USA and all other agricultural sources are considered nonpoint and are not regulated under federal law as mentioned in this paper.
Abstract: Pollution of lakes, rivers, and estuaries from agricultural sources of P is a major water quality problem in the USA. This paper explains the regulatory and nonregulatory programs developed by the U.S. Environmental Protection Agency (USEPA) to implement its legal mandate to control water pollution from these sources. The Clean Water Act defines concentrated animal feeding operations as point sources of pollution that are required to obtain permits to discharge into waters of the USA. All other agricultural sources are considered nonpoint and are not regulated under federal law. The USEPA provides grant money to the states to develop and implement nonpoint source programs. The Coastal Zone Act Reauthorization Amendments of 1990 requires coastal states to adopt nonpoint management measures that are backed by enforceable policies and mechanisms. For water bodies that continue to be impaired despite the basic implementation of these laws and other programs, states are required to develop a total maximum daily load (TMDL). The TMDL process is the quantitative basis for reaching water quality standards. The USEPA is putting a new emphasis on controlling nutrient pollution sources to meet the goal of the Clean Water Act.
222 citations
TL;DR: In this paper, the authors investigated a number of methods that can be used to generate constituent concentrations for use in stormwater modeling, including the use of event mean concentrations (EMCs) and pollutant buildup and washoff formulations.
Abstract: This paper investigates a number of methods that can be used to generate constituent concentrations for use in stormwater modeling. These include the use of event mean concentrations (EMCs) and pollutant buildup and washoff formulations. Suspended solids data collected in the Austin, Texas, area from single-land-use watersheds were used to evaluate the usefulness of these methods. Use of a single EMC for all urban land uses was shown to provide a reasonable estimate of solids loads. This suggests that increases in total suspended solids loads resulting from development will be primarily a function of the increase in runoff volume, which in turn may be related to increased impervious cover. Water quality data did not indicate a strong correlation between initial pollutant load on the watershed and length of the antecedent dry period; however, the concentration of suspended solids in stormwater runoff does follow a simple washoff model.
201 citations
TL;DR: In this article, the authors developed and analyzed models pre- dicting landscape discharge based on material release by an uphill source area, the spatial distribution of riparian buffer along a stream, and retention within the buffer.
Abstract: For landscapes with riparian buffers, we develop and analyze models pre- dicting landscape discharge based on material release by an uphill source area, the spatial distribution of riparian buffer along a stream, and retention within the buffer. We model the buffer as a grid of cells, and each cell transmits a fixed fraction of the materials it receives. We consider the effects of variation in buffer width and buffer continuity, quantify the relative contributions of source elimination and buffer retention to total discharge reduction, and develop statistical relationships to simplify and generalize the models. Width variability reduces total buffer retention, increases the width needed to meet a management goal, and changes the importance of buffer retention relative to source elimination. Variable- width buffers are less efficient than uniform-width buffers because transport through areas of below-average buffer width (particularly gaps) dominates landscape discharge, especially for narrow buffers of highly retentive cells. Uniform-width models overestimate retention, so width variability should be considered when testing for buffer effects or designing buffers for water quality management. Adding riparian buffer to a landscape can decrease material discharge by increasing buffer retention and by eliminating source areas. Source elimination is more important in unretentive or wide buffers, while buffer retention dominates in narrow, retentive buffers. We summarize model results with simpler statistical relationships. For unretentive buffers, average width is the best predictor of landscape discharge, while the frequency of gaps was best for narrow, retentive buffers. Together, both predictors explain >90% of the variance in average landscape transmission for any value of buffer reten- tiveness. We relate our results to ecological theory, landscape-scale buffer effects, buffer management, and water quality models. We recommend more empirical studies of buffer width variability and its effects on material discharge. Landscape models should represent width variability and the nonlinear interactions between buffers and source areas.
121 citations
TL;DR: The U.S. EPA QUAL2E model is currently the standard for river water quality modelling as discussed by the authors, but it does not address a number of practical problems such as stormwater flow events, nonpoint source pollution, and transient streamflow.
102 citations
TL;DR: In this paper, the authors present a framework for combining ecological and economic information to compare management scenarios for nonpoint pollution, a common environmental problem, focusing on the eutrophication of lakes caused by nonpoint phosphorus pollution.
Abstract: The hypothesis that economic damage due to nonpoint pollution exceeds costs of mitigation can be tested by ecologists, economists, and resource managers working at the spatial scale of watersheds for periods of years to decades. We present a framework for combining ecological and economic information to compare management scenarios for nonpoint pollution. Eutrophication of lakes caused by nonpoint phosphorus pollution, a common environmental problem, is the focus of our approach. Economic advantages of mitigating nonpoint pollution increase as the uncertainty of ecological predictions decreases. Uncertainty is measured by the prediction variance of nonpoint pollution models. A major source of variance in nonpoint pollution predictions is the effect of land use change on phosphorus transport. This variance is often large because calibration data sets do not have sufficiently wide ranges of land use variables. Ecological predictions and the resulting economic assessments could be improved by comparative studies of watersheds with contrasting land uses, and by viewing nonpoint pollution management as a large-scale experiment.
01 Jan 1998
TL;DR: Riparian ecosystems have been the subject of ecosystem research for about the last twenty years as mentioned in this paper and have been used as a landscape and watershed management technique to reduce the risk of pollution and to create and preserve healthy stream ecosystems.
Abstract: Riparian (streamside) ecosystems have been the subject of ecosystem research for about the last twenty years. Ecosystem research has shown that riparian areas are especially effective controllers of nitrogen and sediment movement to streams and other water bodies. Nitrogen control is primarily the result of biotic processes. Sediment control is primarily caused by physical processes that are enhanced by such biotic interactions as enhanced infiltration and leaf litter at the soil surface. Riparian areas are increasingly being used as a landscape-and watershed-management technique to reduce the risk of pollution and to create and preserve healthy stream ecosystems. The management practices recommended for riparian areas are based on ecosystem research. Riparian ecosystem policies and management are a success story for the application of ecosystem science to real-world problems. Riparian ecosystem research has been used to develop generalized management practices for USDA action agencies such as the Natural Resources Conservation Service and the Forest Service. Ecosystem-management recommendations for riparian areas have been incorporated into such programs as the Coastal Zone Management Act Reauthorization and the Chesapeake Bay Program. The USDA has incorporated riparian policies into the Conservation Reserve Program (CRP) reauthorized in the 1996 Farm Bill. The CRP allows farmers to voluntarily enroll such environmentally sensitive lands as riparian ecosystems because of the high environmental benefits associated with riparian areas compared to other lands. The success of riparian ecosystem research in shaping riparian policy and management results from multiple factors including: agreement among major studies on the effectiveness of riparian ecosystems for nonpoint-source pollution control; flexibility of management practices; and use of riparian ecosystems for multiple functions.
TL;DR: Statistics suggest that urban land surfaces are the primary nonpoint source of most VOCs, and surface waters in urban areas would most effectively be protected by controlling land-surface sources.
TL;DR: In this paper, a geographical information system (GIS)-based transport model (SEDMOD) was proposed to provide an index of pathogen loading potential to streams by characterizing five key transport parameters: flow-path hydraulic roughness, gradient, and slope shape, stream proximity, and normalized soil moisture index.
Abstract: Recent cases of drinking water contamination by pathogens have underscored the importance of preventing livestock waste from entering surface waters. To this end, analytical tools are needed that can identify subwatersheds or livestock operations that contribute disproportionately to contamination. This paper presents a geographical information system (GIS)-based transport model (SEDMOD) that provides an index of pathogen loading potential to streams by characterizing five key transport parameters: flow-path hydraulic roughness, gradient, and slope shape, stream proximity, and a normalized soil moisture index. We applied SEDMOD to 12 subwatersheds (10 agricultural, 2 forested controls) of the Saw Kill, a tributary of the Hudson River, New York, and compared model predictions with measured fecal coliform (FC) levels. The transport model, combined with a livestock density GIS layer, could explain 50% of the variation in average FC discharge among the subwatersheds (r = 0.71, P = 0.01, n = 12). By contrast, neither total livestock FC output nor predicted FC transport were correlated with geometric mean FC concentration (P >0.05). In a multiple regression, predicted FC transport, mean water temperature, and mean turbidity could account for 80% of the observed variation in FC discharge (r = 0.90, P = 0.001, n = 12). We conclude that, although more field work and algorithm development is needed to yield more accurate quantitative predictions, the model is useful for predicting the relative contribution of diverse livestock operations within a varied landscape. This provides watershed managers and regulators with a rating method to prioritize sites for nonpoint source pollution control.
TL;DR: In this article, the authors developed multiple regression models relating land use to in-stream concentrations of total nitrogen (TOTN) and total phosphorus (TOPP) in eight, low-order watersheds on the coastal plain of South Carolina.
Abstract: This research developed multiple regression models relating land use to in-stream concentrations of total nitrogen (TOTN) and total phosphorus (TOTP) in eight, low-order watersheds on the coastal plain of South Carolina. The study area (4860 km 2 ) included dominant land-use categories of agriculture, forest, urban, and wetland comprising the lower portion of the Lake Marion drainage. Land-use data were obtained from a pre-existing GIS database derived by classification of satellite images. The models partitioned land-use categories according to distance from stream channels using a series of buffer zones around each stream. Effects of point source contributions were removed from observed in-stream concentrations so that nonpoint source effects could be more clearly delineated. All models except two were significant at P 150 m). Land-use change scenarios (converting forest and wetland to agriculture) support the conclusion that management of stream water quality will be most effective with emphasis on riparian and adjacent lands. Seasonal models were generally significant (P < 0.05) and demonstrate that the seasonal profile of stream nutrient concentrations is dependent on the mosaic of land uses in a specific subhasin.
TL;DR: In this article, the authors estimate compliance and transaction costs of reducing nitrogen runoff from dairies in the Lower Susquehanna Watershed by 40% for perfectly targeted and uniform performance standards.
Abstract: Reducing costs of controlling nonpoint source (NPS) pollution will be a high public priority in the next century. Compliance and transaction costs of reducing nitrogen runoff from dairies in the Lower Susquehanna Watershed by 40% are estimated for perfectly targeted and uniform performance standards. The perfectly targeted standard reduces compliance and transaction costs by almost 75% compared with the uniform standard. Future NPS control policies should use spatial information to target policy resources to priority concerns, areas, and farms. Further research is needed to lower the costs and increase the accuracy of spatial information.
TL;DR: A concerted research effort to modify, refine, and advance soil testing for P to achieve environmental as well as agronomic objectives has been underway for the past decade; unfortunately, little of this research has been adopted by soil testing programs in the United States.
Abstract: Modern agricultural management practices for phosphorus (P), including soil testing, can no longer focus exclusively on soil fertility and agricultural productivity but must also address the role of agricultural P in nonpoint source pollution of surface waters. The eutrophication of streams, rivers, lakes, and bays as a result of P loss from soil to water points to the need for advances in soil testing that can contribute to water quality protection. A concerted research effort to modify, refine, and advance soil testing for P to achieve environmental as well as agronomic objectives has been underway for the past decade; unfortunately, little of this research has been adopted by soil testing programs in the United States. The intent of this paper is two‐fold. First, to briefly review some of this research, illustrating its potential value in soil P management programs that, by necessity, must today have both agronomic and environmental components. And second, to provide recommendations as to how ...
TL;DR: In this paper, a watershed approach was used to compare land use indicators (septic system and animal unit densities), to streamwater nitrate-N in the Salmon River near Vancouver, B.C., Canada.
Abstract: Agricultural and residential activities are key non-point sources of nitrogen pollution in urban-rural fringe areas. A GIS-based watershed approach was used to compare land use indicators (septic system and animal unit densities), to streamwater nitrate-N in the Salmon River near Vancouver, B.C., Canada. The density of septic systems was used as an indicator of residential development while animal unit density was used as an indicator of the intensity of agricultural activity. Nitrate-nitrogen (nitrate-N) concentrations as high as 7.1 mg·L−1 were found in the mid-portion of the watershed during the summer months, when streamflow is low and groundwater comprises a large proportion of water in the stream. The major aquifer supplying water to the midsection of the watershed is contaminated with nitrate-N. A comparison of the relationships between septic system and animal unit density and nitrate-N in the upstream to downstream direction provided evidence that both residential and agricultural activities contribute to elevated nitrate-N in the Salmon River mainstem. In contrast, only septic system density corresponded to the pattern of streamwater nitrate-N in Coghlan Creek, the main tributary to the Salmon River.
TL;DR: In this paper, the West Branch of the Delaware River, the major tributary supplying Cannonsville Reservoir, was monitored for eight years from the early 1980s to the early 1990s.
Abstract: Eight years of monitoring data are reviewed and analyzed for the West Branch of the Delaware River, the major tributary supplying Cannonsville Reservoir: 3 years are from the early 1980s, the other 5 years include 1991–1996. Phosphorus, nitrogen, and sediment loads were measured at the mouth of the West Branch using an approach of intensified sampling during runoff events and routine sampling during baseflow intervals. Total river loads of nutrients and sediment are reported on a water-year basis; selected analytes are reported on a monthly basis. Additionally, phosphorus inputs are partitioned into nonpoint and point source loads. The point source phosphorus load decreased about 75% during the 1990's study period primarily due to upgrades at the largest municipal wastewater treatment plant in the watershed. Annual nonpoint source phosphorus loads were variable over the study period: dissolved phosphorus ranged from 6,600 kg · y−1 to 20,800 kg · y−1, while particulate phosphorus ranged from 7,400...
TL;DR: In this paper, the processes of the multipond system in an experimental agricultural watershed located in southeastern China were studied during a 2-yr period (1994-1995), with the purpose of the research being the reduction of nonpoint nutrient pollution at its sources.
Abstract: The processes of the multipond system in an experimental agricultural watershed located in southeastern China were studied during a 2-yr period (1994-1995), with the purpose of the research being the reduction of nonpoint nutrient pollution at its sources. The mechanisms studied included water storage capacity, sedimentation, denitrification, and removal of nutrients by the harvest of macrophytes from ponds and ditches. The results showed that the retention of both water and nutrients depended on the water storage capacity of the ponds, the total pond volume, rainfall, surface runoff, and irrigation amounts. For the years of 1994 and 1995, the water retention rate was 85.5%, while the nutrient retention rate reached 98.1 and 97.8% for total N (TN) and total P (TP), respectively. Sediment deposit was another important mechanism. The average sedimentation rate was 30.0 mm yr(-1) (from 1985-1995). For the whole multipond system (35 ha), the average retention amounts reached 9800 kg of N and 2800 kg of P by sediment accumulation per year. The results demonstrated that denitrification in ponds and ditches was an important mechanism for removing N from the watershed. The highest possible rate was more than 0.17 mg N g(-1) soil during the summer season. The results suggested that the multipond system, which kept water in balance, benefited the water, nutrient, and sediment recycling in the terrestrial ecosystem, as web as helped to reduce agricultural nonpoint pollution at its sources. Therefore, the multipond system, with its low cost in construction and maintenance, is recommended as a good practice both for the control of nonpoint pollution at its sources and for sustainable agricultural development.
TL;DR: A field monitoring study of a riparian forest buffer zone was conducted to determine the impact of the riparian ecosystem on reducing the concentration of agricultural nonpoint source pollutants as discussed by the authors, where groundwater samples were collected from 20 sampling locations between May 1993 and December 1994, and analyzed for NO 3, PO 4, and NH 4 -N.
Abstract: A field monitoring study of a riparian forest buffer zone was conducted to determine the impact of the riparian ecosystem on reducing the concentration of agricultural nonpoint source pollutants. Groundwater samples were collected from 20 sampling locations between May 1993 and December 1994, and analyzed for NO 3 -N, PO 4 , and NH 4 -N. Statistical analyses such as Friedman's test, cluster analysis, cross correlation analysis and Duncan's test were performed for the nutrient data. The study showed that the riparian buffer zone was effective in reducing nitrate concentrations originating from upland agricultural fields. Instream nitrate concentrations were 48 percent less than those measured in the agricultural field. Reductions in concentrations in sampling locations at the wetland edge ranged from 16 to 70 percent. The mean nitrate concentrations in forested hill slope were 45 percent less than concentrations in a well located in an upland agricultural field. Meanwhile, the concentrations of phosphate and ammonia did not follow any specific spatial trend and were generally higher during the summer season for most sampling locations.
TL;DR: In this paper, the authors evaluated the economic value of riparian buffers in reducing agricultural nonpoint source pollution in a Midwestern agricultural watershed using the CARE and SWAT models, respectively.
Abstract: This study determines the most cost effective spatial pattern of farming systems for improving water quality and evaluates the economic value of riparian buffers in reducing agricultural nonpoint source pollution in a Midwestern agricultural watershed. Economic and water quality impacts of alternative farming systems are evaluated using the CARE and SWAT models, respectively. The water quality benefits of riparian buffers are estimated by combining experimental data and simulated water quality impacts of fanning systems obtained using SWAT. The net economic value of riparian buffers in improving water quality is estimated by total watershed net return with riparian buffers minus total watershed net return without riparian buffers minus the opportunity cost of riparian buffers. Exclusive of maintenance cost, the net economic value of riparian buffers in reducing atrazine concentration from 45 to 24 ppb is $612,117 and the savings in government cost is $631,710. Results strongly support efforts that encourage farmers to develop or maintain riparian buffers adjacent to streams.
TL;DR: In this article, an agricultural watershed in the Iowa Loess Hills with a 23-year history of annual corn production with average N fertilization is studied, where headcut seepage is transported through a natural riparian zone and observed as weir baseflow; surface runoff is measured separately.
Abstract: Nonpoint source pollution of surface water by nitrate from agricultural activities is a national problem. An agricultural watershed in the Iowa Loess Hills with a 23-year history of annual corn production with average N fertilization is studied. Headcut seepage is transported through a natural riparian zone and observed as weir baseflow; surface runoff is measured separately. Nitrate runoff graphs illustrate the importance of high-frequency sampling of each event to permit quantitative estimation of chemical loss. The concentration of nitrate carried from the field in basin drainage steadily increased from 20 mg L-1 in 1991. The rate of cumulative increase in the amount of applied N is greater than the rate of removal by the crop. Over the 23-year record, 23% of the mean annual application of N remains stored and available for leaching or chemical conversion by soil microbes. Nitrate removal during early spring snowmelt surface runoff shows a diurnal pattern that corresponds to the d...
TL;DR: In this paper, the Muddy Brook watershed was monitored for two years and the development of a mathematical model that can simulate the movement of nitrogen and the evaluation of the non-linear response of the watershed to nitrogen loadings was presented.
TL;DR: In this article, preliminary screening to evaluate the vulnerability of groundwater systems of Indiana was conducted using the DRASTIC and SEEPAGE models at a 1:250,000 scale using the NRCS state soils geographic database (STATSGO) and other GIS databases provided spatial data required for these models.
Abstract: Regional scale analyses identifying the areas with nitrate leaching from non-point sources of pollution will aid
in development and implementation of efficient groundwater quality management strategies. Preliminary screening to
evaluate the vulnerability of groundwater systems of Indiana was conducted using the DRASTIC and SEEPAGE models at
a 1:250,000 scale. The NRCS state soils geographic database (STATSGO) was used to extract the soil information
required for the analysis and other GIS databases provided spatial data required for these models. The accuracy of the
DRASTIC and SEEPAGE results were evaluated by comparing the results with well water quality data sampled across the
state. The comparison showed that approximately 81% of nitrate detections were within the highest vulnerability category
(high plus very high) for DRASTIC and nearly 62% in this category for SEEPAGE despite these areas representing 25%
and 28% of the state in each model, respectively. These regional scale analyses show significant potential as screening
tools for policy and decision making in groundwater management.
TL;DR: In this paper, a water quality project was initiated in Duplin County, North Carolina, in the 2044-ha Herrings Marsh Run watershed, where a swine farm within this monitored watershed expanded its operation from 3,300 to more than 14,000 animals.
Abstract: Nonpoint source pollution from agriculture has been a major concern, particularly where intensive agricultural operations exist near environmentally sensitive waters. To address these concerns, a water quality project was initiated in Duplin County, North Carolina, in the 2044-ha Herrings Marsh Run watershed. A swine farm within this monitored watershed expanded its operation from 3,300 to more than 14,000 animals. Groundwater nitrate-N increased significantly in three of the seven wells located adjacent to the spray field and in the adjoining riparian zone. Stream nitrate-N concentrations have increased after the expansion of the swine operation in the colder months, but concentrations have remained approximately the same during the warmer months. Stream ammonia-N mean concentrations after expansion have increased as well as the frequency and magnitude of ammonia-N concentration spikes. Ortho-phosphate concentrations in the stream water have been relatively consistent over the study period. The riparian zone is reducing the impact of spray field groundwater nitrate concentrations and ammonia loadings in an adjacent stream.
01 Jan 1998
TL;DR: In this article, Pollution Control Technology in the Private Sector (PCT) in the private sector, Contaminants, Energy and Climate, Air Pollution control, Water Pollution: Wastewater, Potable Water, Soil, Waste, Recycling.
Abstract: Fundamentals.- Pollution Control Technology in the Private Sector.- Contaminants.- Energy and Climate.- Air Pollution Control.- Water Pollution: Wastewater.- Potable Water.- Soil.- Waste.- Recycling.- Appendices.
DOI•
26 May 1998
TL;DR: In 1997, uncontrolled forest fires burning in Indonesia resulted in a regional air pollution episode of smoke which impacted several Southeast Asian nations as discussed by the authors, where elevated levels of particulate matter air pollution were observed for a period of approximately 2 months in many areas, with a severe episode occurring during most of the month of September.
Abstract: In 1997, uncontrolled forest fires burning in Indonesia resulted in a regional air pollution episode of smoke which impacted several Southeast Asian nations. Beginning in late July 1997, elevated levels of particulate matter air pollution were observed for a period of approximately 2 months in many areas, with a severe episode occurring during most of the month of September. During this episode, particle levels in some areas were up to 15 times higher than normal levels. Exposures to “haze”-type air pollution can be substantial and are of public health concern due to the large numbers of individuals who may be exposed.
Journal Article•
TL;DR: In this paper, which agricultural non-point source water quality model is the best option to meet the needs of agricultural users? And what new agricultural nonpoint water quality models are being proposed.
Abstract: Which agricultural non-point source water quality model is the best option to meet your needs? What new