Development of a Coupled Water Quality Model

2017 ◽  
Vol 60 (4) ◽  
pp. 1153-1170 ◽  
Author(s):  
Lili Wang ◽  
Dennis C. Flanagan ◽  
Keith A. Cherkauer
Keyword(s):  
Water Quality ◽  
Time Series ◽  
Soil Erosion ◽  
Total Phosphorus ◽  
Land Management ◽  
Management Practices ◽  
Nitrate Nitrogen ◽  
Storm Events ◽  
Nutrient Losses ◽  
Soluble Phosphorus

Abstract. . Nonpoint-source (NPS) pollutants, especially from agriculture, continue to be a primary source of waterquality degradation problems. Effective land management decisions at the field scale must be made to minimize nutrient losses that could pollute streams. Existing NPS models often cannot directly estimate the impacts of different land management practices or determine the effectiveness of combined best management practices (BMPs) in a distributed way at the farm scale. In many cases, they rely on application of the Universal Soil Loss Equation (USLE) or its improved versions, which represent fields in a lumped fashion and use empirical rather than process-based modeling methodologies. In this study, a coupled Water Erosion Prediction Project and Water Quality (WEPP-WQ) model was completed, updated, improved, and evaluated for simulation of hydrology, soil erosion, and water quality. The WEPP model is a well-established process-based model that simulates runoff and erosion processes from a hillslope. The water quality components are based on those of the Soil and Water Assessment Tool (SWAT). A single overland flow element (OFE) on a hillslope is used to represent a single soil and land use management. The WEPP-WQ model was tested by comparing simulated values from the coupled model with observed nutrient and sediment concentrations in surface runoff following storm events at experimental sites near Waterloo in northeastern Indiana and at the Throckmorton Purdue Agricultural Center in west central Indiana. Time series evaluation of the WEPP-WQ model was performed with observed nutrient and sediment losses from an experimental plot near Tifton, Georgia. The model performed quite well in simulating nutrient losses for single storm events, with R2 greater than 0.8, Nash-Sutcliffe efficiency (NSE) greater than 0.65, and percent bias (PBIAS) less than 31% for runoff, sediment, nitrate nitrogen, total nitrogen, soluble phosphorus, and total phosphorus losses. In predicting time series nutrient loss, the WEPP-WQ model simulated daily nitrate nitrogen losses adequately, with the ratio of the root mean square error to the standard deviation of measured data (RSR) less than 0.7, NSE greater than 0.55, and PBIAS within the range of ±40%. Comparisons between simulated soluble phosphorus, total phosphorus, and literature results were performed due to the absence of an available observational dataset. The WEPP-WQ model with a single OFE in this study provides a basic but important step for the development of WEPP-WQ models with multiple OFEs that can evaluate the effectiveness of BMPs Keywords: Modeling, Nitrogen, Phosphorus, Soil erosion, Water quality, WEPP.

scholarly journals Effectiveness of Best Management Practices to Reduce Phosphorus Loading to a Highly Eutrophic Lake

2018 ◽  
Vol 15 (10) ◽  
pp. 2111 ◽  
Author(s):  
Alan D. Steinman ◽  
Michael Hassett ◽  
Maggie Oudsema
Keyword(s):  
Water Quality ◽  
Total Phosphorus ◽  
Best Management Practices ◽  
Management Practices ◽  
Soluble Reactive Phosphorus ◽  
Base Flow ◽  
Phosphorus Loading ◽  
Storm Events ◽  
Best Management ◽  
Significant Difference

Reducing nonpoint source pollution is an ongoing challenge in watersheds throughout the world. Implementation of best management practices, both structural and nonstructural, is the usual response to this challenge, with the presumption that they are effective. However, monitoring of their efficacy is not a standard practice. In this study, we evaluate the effectiveness of two wetland restoration projects, designed to handle runoff during high flow events and serve as flow-through retention basins before returning flow further downstream. The Macatawa Watershed is located in west Michigan, is heavily agricultural, and drains into Lake Macatawa, a hypereutrophic lake with total phosphorus concentrations usually exceeding 100 µg/L. We measured turbidity, total phosphorus, and soluble reactive phosphorus both upstream and downstream of these wetland complexes during base flow and storm events. While both turbidity and phosphorus increased significantly during storm events compared to baseflow, we found no significant difference in upstream vs. downstream water quality two years following BMP construction. We also measured water quality in Lake Macatawa, and found the lake remained highly impaired. Possible reasons for the lack of improved water quality: (1) The restored wetlands are too young to function optimally in sediment and phosphorus retention; (2) the scale of these BMPs is too small given the overall loads; (3) the locations of these BMPs are not optimal in terms of pollutant reduction; and (4) the years following postconstruction were relatively dry so the wetlands had limited opportunity to retain pollutants. These possibilities are evaluated.

Applying the Soil Water Assessment Tool to 5th Canadian Division Support Base Gagetown

2014 ◽  
Vol 49 (4) ◽  
pp. 372-385
Author(s):  
Shawn Burdett ◽  
Michael Hulley ◽  
Andy Smith
Keyword(s):  
Water Quality ◽  
Soil Water ◽  
Land Management ◽  
Management Practices ◽  
Assessment Tool ◽  
Anthropogenic Activities ◽  
Quality Model ◽  
Sediment Yields ◽  
Soil Water Assessment Tool ◽  
Water Assessment

A hydrologic and water quality model is sought to establish an approach to land management decisions for a Canadian Army training base. Training areas are subjected to high levels of persistent activity creating unique land cover and land-use disturbances. Deforestation, complex road networks, off-road manoeuvres, and vehicle stream crossings are among major anthropogenic activities observed to affect these landscapes. Expanding, preserving and improving the quality of these areas to host training activities for future generations is critical to maintain operational effectiveness. Inclusive to this objective is minimizing resultant environmental degradation, principally in the form of hydrologic fluctuations, excess erosion, and sedimentation of aquatic environments. Application of the Soil Water Assessment Tool (SWAT) was assessed for its ability to simulate hydrologic and water quality conditions observed in military landscapes at 5th Canadian Division Support Base (5 CDSB) Gagetown, New Brunswick. Despite some limitations, this model adequately simulated three partial years of daily watershed outflow (NSE = 0.47–0.79, R2 = 0.50–0.88) and adequately predicted suspended sediment yields during the observation periods (%d = 6–47%) for one highly disturbed sub-watershed in Gagetown. Further development of this model may help guide decisions to develop or decommission training areas, guide land management practices and prioritize select landscape mitigation efforts.

scholarly journals Limitations of Improved Nitrogen Management to Reduce Nitrate Leaching and Increase Use Efficiency

2001 ◽  
Vol 1 ◽  
pp. 10-16 ◽  
Author(s):  
James L. Baker
Keyword(s):  
Water Quality ◽  
Nitrate Leaching ◽  
Management Practices ◽  
Nitrate Nitrogen ◽  
Nitrogen Management ◽  
N Leaching ◽  
N Loss ◽  
Use Efficiency ◽  
Rate Method ◽  
N Management

The primary mode of nitrogen (N) loss from tile-drained row-cropped land is generally nitrate-nitrogen (NO3-N) leaching. Although cropping, tillage, and N management practices can be altered to reduce the amount of leaching, there are limits as to how much can be done. Data are given to illustrate the potential reductions for individual practices such as rate, method, and timing of N applications. However, most effects are multiplicative and not additive; thus it is probably not realistic to hope to get overall reductions greater than 25 to 30% with in-field practices alone. If this level of reduction is insufficient to meet water quality goals, additional off-site landscape modifications may be necessary.

The effect of land management practices on soil erosion and land desertification in an olive grove

2013 ◽  
Vol 29 (4) ◽  
pp. 597-606 ◽  
Author(s):  
O. Kairis ◽  
C. Karavitis ◽  
A. Kounalaki ◽  
L. Salvati ◽  
C. Kosmas
Keyword(s):  
Soil Erosion ◽  
Land Management ◽  
Management Practices ◽  
Olive Grove ◽  
Land Desertification

scholarly journals Analysis of Farmers’ Perception on the Impact of Land Degradation Hazard on Agricultural Land Productivity in Jeldu District in West Shewa Zone, Oromia, Ethiopia

2018 ◽  
Vol 8 (2) ◽  
pp. 20
Author(s):  
Tesfaye Samuel Saguye
Keyword(s):  
Soil Erosion ◽  
Land Management ◽  
Land Degradation ◽  
Management Practices ◽  
Local Community ◽  
Agricultural Land ◽  
Land Productivity ◽  
Community Knowledge ◽  
Process Indicators ◽  
The Impact

Land degradation is increasing in severity and extent in many parts of the world. Success in arresting land degradation entails an improved understanding of its causes, process, indicators and impacts. Various scientific methodologies have been employed to assess land degradation globally. However, the use of local community knowledge in elucidating the causes, process, indicators and effects of land degradation has seen little application by scientists and policy makers. Land degradation may be a physical process, but its underlying causes are firmly rooted in the socio-economic, political and cultural environment in which land users operate. Analyzing the root causes and effects of land degradation from local community knowledge, perception and adapting strategies perspective will provide information that is essential for designing and promoting sustainable land management practices. The main objective of this study was to analyze the perceptions of farmers’ on the impact of land degradation hazard on agricultural land productivity decline associated with soil erosion and fertility loss. The study used a multistage sampling procedure to select sample respondent households. The sample size of the study was 120 household heads and 226 farm plots managed by these farmers. The primary data of the study were collected by using semi-structured Interview, focus group discussions and field observation. Both descriptive statistics and econometric techniques were used for data analysis. Descriptive results show that 57percent of the respondents were perceived the severity and its consequence on agricultural land productivity. The following indicators of soil erosion and fertility loss were generally perceived and observed by farmers’ in the study area: gullies formations, soil accumulation around clumps of vegetation, soil deposits on gentle slopes, exposed roots, muddy water, sedimentation in streams and rivers, change in vegetation species, increased runoff, and reduced rooting depth. The direct human activities which were perceived to be causing land degradation in the study area include: deforestation and clearing of vegetation, overgrazing, steep slope cultivation and continuous cropping. The farmers’ possibility of perceiving the impact of land degradation hazard on agricultural land productivity was primarily determined by institutional, psychological, demographic and by bio-physical factors. Farmers who perceive their land as deteriorating and producing less than desired, tend to adopt improved land management practices. On the other hand, farmers who perceive their land to be fertile tend to have low adoption of conservation practices. In order to overcome this land degradation and its consequent effects, the study recommended a need for the government to enforce effective policies to control and prevent land degradation and these policies should be community inclusive /participatory founded up on indigenous and age-honored knowledge and tradition of farmers' natural resource management as well as introduced scientific practices.

DRAINMOD-P: A Model for Simulating Phosphorus Dynamics and Transport in Drained Agricultural Lands: I. Model Development

2021 ◽  
Vol 64 (6) ◽  
pp. 1835-1848
Author(s):  
Manal H. Askar ◽  
Mohamed A. Youssef ◽  
Peter A. Vadas ◽  
Dean L. Hesterberg ◽  
Aziz Amoozegar ◽  
...  
Keyword(s):  
Water Quality ◽  
Soil Erosion ◽  
Best Management Practices ◽  
Management Practices ◽  
Subsurface Drainage ◽  
Water Quality Modeling ◽  
List Type ◽  
Macropore Flow ◽  
Drainage Systems ◽  
P Cycling

HighlightsDRAINMOD-P has been developed to simulate phosphorus (P) dynamics in drained croplands.Key hydrological and biochemical processes affecting P cycling are represented in the model.The model predicts surface and subsurface P losses as affected by weather, soil, and management factors.Abstract. High phosphorus (P) loads to streams and lakes can promote harmful algae blooms and cause water quality deterioration. Recent research has identified subsurface drainage as an important pathway for the transport of dissolved P from drained croplands to receiving surface water bodies, particularly when macropore flow contributes a considerable portion of the subsurface drainage outflow. Currently, a few models are capable of simulating P dynamics in poorly drained soils with artificial drainage systems. The objective of this study was to develop DRAINMOD-P, a field-scale, process-based model that simulates P cycling and transport in drained croplands. Processes represented in the model include atmospheric deposition, organic and inorganic fertilizer applications, plant uptake, sediment-bound and dissolved P losses in both surface runoff and subsurface drainage, tillage practices, and P mineralization and immobilization. The model predicts P losses under different management practices, climatic conditions, drainage systems, and crop rotations. The model is an extension to the nitrogen model DRAINMOD-NII, with full integration of the nitrogen and P model components. DRAINMOD-P uses the recently modified hydrology component that simulates macropore flow. A soil erosion component, based on the RUSLE approach, has been incorporated into the model to estimate sediment loss and associated particulate P loss. Sediment deposition in tile drains is considered to quantify particulate P settling in the drainage system. In this article, we review the approaches used in DRAINMOD-P for simulating P-related processes. Model testing against field-measured data from a subsurface-drained field in northwest Ohio is presented in a companion article. Keywords: Best management practices, Phosphorus model, Phosphorus processes, Soil erosion, Water quality modeling.

Iowa Statewide Stream Nitrate Loading: 2017-2018 Update

2019 ◽  
Vol 126 (1-4) ◽  
pp. 6-12 ◽  
Author(s):  
Christopher S. Jones ◽  
Keith E. Schilling
Keyword(s):  
Water Quality ◽  
Mississippi River ◽  
Best Management Practices ◽  
Management Practices ◽  
Nitrate Nitrogen ◽  
Nitrogen Loading ◽  
Point Sources ◽  
Nutrient Reduction ◽  
Stream Network ◽  
Discharge Data

In response to ongoing hypoxia in the Gulf of Mexico, several states in the Mississippi River basin have adopted nutrient reduction plans in recent years designed to arrest the flow of nitrogen (N) and phosphorus (P) from both point and non-point sources to the stream network. Iowa's Nutrient Reduction Strategy, implemented in 2012, aims to reduce stream loading of these nutrients by 45% within a yet-to-be-defined time frame. Because the state has chosen to integrate accountability into the strategy through the numerical objective, ongoing water monitoring is necessary to credibly measure progress. The primary objective of this research was to use water quality monitoring and discharge data to update statewide nitrate-nitrogen (NO3-N) loading using the combined data sets generated by in situ water quality sensors and traditional grab sample monitoring conducted by state government. Our research shows that the 5-year running annual average of nitrate-nitrogen loading continues to increase, and after the 2018 water year is 73% higher than that calculated in 2003. Loads from Iowa areas draining to the Missouri River are increasing more rapidly than loads from areas draining to the upper Mississippi River: 132% versus 55% since 2003. This shows that best management practices designed to stem the loss of nutrients from the corn-soybean system must be widely adopted and robustly designed for extreme environmental conditions if Iowa is to meet its water quality objectives.

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