Evaluation of AnnAGNPS in cold and temperate regions

2006 ◽  
Vol 53 (2) ◽  
pp. 263-270 ◽  
Author(s):  
S. Das ◽  
R.P. Rudra ◽  
P.K. Goel ◽  
B. Gharabaghi ◽  
N. Gupta

Identification of the pollution sources and understanding the processes related to runoff generation and pollution transportation is effective for the water quality management and selection of the Best Management Practices. The ANNualized AGricultural Non-Point Source (AnnAGNPS) model was applied to a watershed in Southern Ontario to evaluate the hydrology and sediment component from the non-point sources. The model was run for two years (1998 to 1999); one year's data was used to calibrate and the second year's data was used for validation purposes. The model has under predicted runoff amount and over predicted the sediment yield. However, the simulated runoff and sediment yield compared fairly well with the observed data indicating that the model had an acceptable performance in simulation of runoff and sediment. The study is still in progress to assess its performance for estimation of TMDL and improvements needed for the model to use under Ontario conditions.

2006 ◽  
Vol 41 (3) ◽  
pp. 283-295 ◽  
Author(s):  
Renaud Quilbé ◽  
Alain N. Rousseau ◽  
Pierre Lafrance ◽  
Jacinthe Leclerc ◽  
Mohamed Amrani

Abstract Numerous models have been developed over the last decades to simulate the fate of pesticides at the watershed scale. Based on a literature review, we inventoried thirty-six models categorized as management, research, screening or multimedia models, each of them having specific strengths and weaknesses. Given this large number of models, it may be difficult for potential users (stakeholders or scientists) to find the most suited one with respect to their needs. To help in this process, this paper proposes a pragmatic approach based on a multi-criteria analysis. Selection criteria are defined following the user's needs and classified in five classes: modelling characteristics, output variables, model applicability, possibilities to simulate best management practices (BMPs) and ease of use. The relative importance of each criterion is quantified by a weight and the total score of a model is calculated by adding the resulting weights of satisfied criteria. This selection framework is illustrated with a case study that consists in selecting a model to develop water quality standards at the watershed scale with respect to the implementation of BMPs. This resulted in the selection of three models: BASINS, SWAT and GIBSI.


PeerJ ◽  
2019 ◽  
Vol 7 ◽  
pp. e7093
Author(s):  
Solmaz Rasoulzadeh Gharibdousti ◽  
Gehendra Kharel ◽  
Arthur Stoecker

Best management practices (BMPs) are commonly used to reduce sediment loadings. In this study, we modeled the Fort Cobb Reservoir watershed located in southwestern Oklahoma, USA using the Soil and Water Assessment Tool (SWAT) and evaluated the impacts of five agricultural BMP scenarios on surface runoff, sediment yield, and crop yield. The hydrological model, with 43 sub-basins and 15,217 hydrological response units, was calibrated (1991–2000) and validated (2001–2010) against the monthly observations of streamflow, sediment grab samples, and crop-yields. The coefficient of determination (R2), Nash-Sutcliffe efficiency (NS) and percentage bias (PB) were used to determine model performance with satisfactory values of R2 (0.64 and 0.79) and NS (0.61 and 0.62) in the calibration and validation period respectively for streamflow. We found that contouring practice reduced surface runoff by more than 18% in both conservation tillage and no-till practices for all crops used in this modeling study. In addition, contour farming with either conservation tillage or no-till practice reduced sediment yield by almost half. Compared to the conservation tillage practice, no-till practice decreased sediment yield by 25.3% and 9.0% for cotton and grain sorghum, respectively. Using wheat as cover crop for grain sorghum generated the lowest runoff followed by its rotation with canola and cotton regardless of contouring. Converting all the crops in the watershed into Bermuda grass resulted in significant reduction in sediment yield (72.5–96.3%) and surface runoff (6.8–38.5%). The model can be used to provide useful information for stakeholders to prioritize ecologically sound and feasible BMPs at fields that are capable of reducing sediment yield while increasing crop yield.


2018 ◽  
Vol 26 (3) ◽  
pp. 255-272 ◽  
Author(s):  
Kristen A. Kieta ◽  
Philip N. Owens ◽  
David A. Lobb ◽  
Jason A. Vanrobaeys ◽  
Don N. Flaten

The movement of excess phosphorus (P) into streams, rivers, and lakes poses a significant threat to water quality and the health of aquatic ecosystems and thus, P has been targeted for reduction. In landscapes dominated by agriculture, P is primarily transported through non-point sources, which a number of best management practices aim to target. One such practice is vegetated buffer strips (VBS), which are designed to use dense vegetation above the surface and extensive root systems below the surface to reduce runoff velocity, trap sediments, increase infiltration, and increase plant uptake of nutrients. The effectiveness of VBS in reducing P concentrations has been studied and reviewed, but most studies have been undertaken in warm or temperate climates, where runoff is primarily driven through summer rainfall events and when vegetation is actively growing. In cold climates, the majority of runoff occurs during the snowmelt period, when soils are frozen and vegetation has been flattened by snow and ice over the winter period and is not actively taking up nutrients. These conditions hinder the ability of VBS to work as designed. Additionally, frozen vegetation can release P after undergoing freeze–thaw cycles (FTCs). Thus, this review aimed to (i) summarize research designed to determine the effectiveness of VBS in reducing P transport in cold climates, (ii) collate research on the potential for vegetation to release P after undergoing FTCs, and (iii) identify research gaps to be addressed in determining VBS effectiveness in cold climates. Cold-climate VBS implemented in Canada, the northern United States, and northern Europe have shown P removal efficiencies ranging from −36% to +89%, a range that identifies the uncertainty surrounding the use of VBS in these landscapes. However, there is consensus among researchers globally that vegetation does release P after undergoing FTCs, though P concentrations from different species vary across studies. The design and management of VBS in cold climates requires careful consideration, and VBS may not always be the best management strategy to reduce P transport. Future research should be undertaken at a larger scale in natural systems and focus on VBS design and management strategies.


2019 ◽  
Vol 19 (12) ◽  
pp. 2767-2779 ◽  
Author(s):  
Gyumin Lee ◽  
Kyung Soo Jun ◽  
Minji Kang

Abstract. This study aimed to develop a risk-based approach for determining control areas to manage non-point source pollution, developing a framework to prioritize catchments by considering the characteristics of polluted runoff from non-point sources. The best management, decision-making, and scientific approaches, such as the technique for order of preference by similarity to ideal solution (TOPSIS) and the Delphi technique, are required for the designation of control areas and the application of the best management practices to the control areas. Multi-criteria decision-making (MCDM) methods can handle the diversity and complexity of non-point source pollution. The Delphi technique was employed for selecting the assessment criteria/sub-criteria and determining their weights. Sub-criteria for each catchment unit were scored with either a quantitative or qualitative scale. All non-point pollution sources in mainland Republic of Korea were included, with the exception of a few islands, with catchment prioritization and pollution vulnerability evaluations shown as thematic maps. This study contributes to the field by developing a new risk-based approach for ranking and prioritizing catchments; this provides valuable information for the Ministry of Environment to use to identify control areas and manage non-point source pollution.


2015 ◽  
Vol 33 (16) ◽  
pp. 1855-1863 ◽  
Author(s):  
Pamela L. Kunz

We have come a long way in our understanding and treatment of neuroendocrine tumors since the term “karzinoide” was coined in 1907. Neuroendocrine tumors are a group of biologically and clinically heterogeneous neoplasms that most commonly originate in the lungs, GI tract, and pancreas. The selection of initial and subsequent therapies requires careful consideration of both tumor and treatment characteristics. With recent advances, we now have more tools for the diagnosis and treatment of our patients. This comprehensive review article summarizes recent advances in the field of neuroendocrine tumors and places them into context for best management practices.


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