scholarly journals Watershed Response to Legacy Phosphorus and Best Management Practices in an Impacted Agricultural Watershed in Florida, U.S.A.

Land ◽  
2021 ◽  
Vol 10 (9) ◽  
pp. 977
Author(s):  
Yogesh P. Khare ◽  
Rajendra Paudel ◽  
Ruscena Wiederholt ◽  
Anteneh Z. Abiy ◽  
Thomas Van Lent ◽  
...  
Keyword(s):  
Water Quality ◽  
Best Management Practices ◽  
Environmental Planning ◽  
Management Practices ◽  
Soil Phosphorus ◽  
Agricultural Watershed ◽  
Assessment Model ◽  
Evaluation Tool ◽  
South Central ◽  
P Sources

Soil phosphorus (P) built up due to past management practices, legacy P, in the Lake Okeechobee Watershed (LOW) in south-central Florida, U.S.A., is often discussed as the root cause of lake eutrophication. Improvement of the lake’s water quality requires the identification of critical P sources and quantifying their contributions. We performed a global sensitivity analysis of the Watershed Assessment Model (WAM), a common evaluation tool in LOW environmental planning, using the Morris method. A pre-calibrated WAM setup (Baseline) of the LOW sub-watershed, Taylor Creek Nubbin Slough (TCNS), was used as a test case. Eight scenarios were formulated to estimate the contributions of various P sources. The Morris analysis indicated that total phosphorus (TP) loads were highly sensitive to legacy P in improved pastures, the major land use covering 46.2% of TCNS. The scenario modeling revealed that legacy P, inorganic fertilizers, and other sources contribute 63%, 10%, and 32%, respectively, to the Baseline TP load of 111.3 metric tons/y to the lake. Improved pastures, dairies, citrus, and field crops are the top TP load contributors. Our results have important implications for water quality improvement plans in the LOW and highlighted the need for accurate spatial mapping of legacy P and incorporation of such information in modeling efforts for watersheds demonstrating legacy P problems.

scholarly journals Summer Dissolved Oxygen Concentrations in Forested Streams of Northern Louisiana

2003 ◽  
Vol 27 (2) ◽  
pp. 92-99 ◽  
Author(s):  
George Ice ◽  
Brian Sugden
Keyword(s):  
Water Quality ◽  
Dissolved Oxygen ◽  
Best Management Practices ◽  
Management Practices ◽  
Aquatic Communities ◽  
Central Plains ◽  
Best Management ◽  
South Central ◽  
Forest Stream ◽  
Management Effects

Abstract Dissolved oxygen (DO) concentrations are critical to aquatic communities and are an important measure of water quality conditions in streams. Best Management Practices that maintain shade near streams and avoid introduction of slash should minimize forest management effects on DO concentrations. However, many streams in the South Central Plains Ecoregion of Louisiana have summer DO concentrations below the 5 mg/L criterion recommended by EPA. Based on a synoptic survey of 43 least-impaired and reference forest stream reaches, we found that over 80% of these reaches had DO concentrations below 5 mg/L, and almost 60% of monitored sites had DO concentrations below 3 mg/L. These low DO concentrations are associated with low streamflow velocities and organic channel bottoms. Unachievable DO standards in the region need to be addressed to realistically reflect local environmental conditions. South. J. Appl. For. 27(2):92–99.

Using Atmospheric Fallout Radionuclides 137Cs and 210Pbxs to Identify Sources of Suspended Sediment in an Agricultural Watershed

2019 ◽  
Vol 62 (2) ◽  
pp. 529-538
Author(s):  
Jasmeet Lamba ◽  
K. G. Karthikeyan ◽  
Anita M. Thompson ◽  
Kritika Malhotra ◽  
Natalie L. H. Huisman ◽  
...  
Keyword(s):  
Land Use ◽  
Suspended Sediment ◽  
Best Management Practices ◽  
Management Practices ◽  
Transport Processes ◽  
Agricultural Watershed ◽  
Atmospheric Fallout ◽  
Fallout Radionuclides ◽  
South Central ◽  
Mixed Land Use

Abstract. The use of atmospheric fallout radionuclides as sediment tracers can provide valuable information on sediment transport processes within watersheds. Research was conducted in cropland and mixed land use subwatersheds of the Pleasant Valley watershed (50 km2) in south-central Wisconsin to identify sources of suspended sediment using cesium-137 (137Cs) and excess lead-210 (210Pbxs). In the cropland-dominated subwatershed, contributions to suspended sediment from in-stream and agricultural sources ranged from 36% to 81% and from 19% to 64%, respectively. In the mixed land use subwatershed, contributions to suspended sediment from in-stream and agricultural sources ranged from 68% to 100% and from 0% to 32%, respectively. The relative contribution to suspended sediment from agricultural sources was greater in the cropland subwatershed compared to the mixed land use subwatershed. The phosphorus (P) concentration in suspended sediment and fine sediment deposited on the streambed varied from 601 to 1545 mg kg-1, and cropland areas were the dominant sources of P-enriched sediment in streams. The legacy P and sediment in this watershed can result in a lag time between implementation of best management practices and attainment of desired water quality improvement. Depending on the fingerprinting properties considered (metals vs. fallout radionuclides) and suspended sediment source considerations, the source apportionment results may vary. Keywords: Fallout radionuclides, Legacy sediment, Phosphorus, Sediment fingerprinting, Soil erosion, Streambanks.

scholarly journals Evaluation of nutrient retention in vegetated filter strips using the SWAT model

2017 ◽  
Vol 76 (10) ◽  
pp. 2742-2752 ◽  
Author(s):  
Alper Elçi
Keyword(s):  
Water Quality ◽  
Best Management Practices ◽  
Management Practices ◽  
Swat Model ◽  
Assessment Model ◽  
Septic Tank ◽  
Nutrient Loads ◽  
Western Turkey ◽  
Discharge Data ◽  
The Impact

Abstract Nutrient fluxes in stream basins need to be controlled to achieve good water quality status. In stream basins with intensive agricultural activities, nutrients predominantly come from diffuse sources. Therefore, best management practices (BMPs) are increasingly implemented to reduce nutrient input to streams. The objective of this study is to evaluate the impact of vegetated filter strip (VFS) application as an agricultural BMP. For this purpose, SWAT is chosen, a semi-distributed water quality assessment model that works at the watershed scale, and applied on the Nif stream basin, a small-sized basin in Western Turkey. The model is calibrated with an automated procedure against measured monthly discharge data. Nutrient loads for each sub-basin are estimated considering basin-wide data on chemical fertilizer and manure usage, population data for septic tank effluents and information about the land cover. Nutrient loads for 19 sub-basins are predicted on an annual basis. Average total nitrogen and total phosphorus loads are estimated as 47.85 t/yr and 13.36 t/yr for the entire basin. Results show that VFS application in one sub-basin offers limited retention of nutrients and that a selection of 20-m filter width is most effective from a cost–benefit perspective.

A Survey of Nursery Water Quality Best Management Practices

HortScience ◽  
1998 ◽  
Vol 33 (3) ◽  
pp. 501e-502
Author(s):  
Cody J. White ◽  
Michael A. Schnelle ◽  
Gerrit W. Cuperus
Keyword(s):  
Water Quality ◽  
Best Management Practices ◽  
Management Practices ◽  
Cultural Practices ◽  
Plant Materials ◽  
Best Management ◽  
Employee Safety ◽  
Current Water ◽  
Management Approaches ◽  
Environmentally Sound

A survey was designed to assess high-risk areas with respect to environmental contamination, specifically how it relates to water quality. Oklahoma growers of all economic levels, retail and/or wholesale, were queried at their place of business for their current state of implementing best management practices (BMPs) and other strategic actions that could potentially affect current and future water quality standards. Specific areas such as the physical environment of the nursery, primary pesticides and fertilizers used, Integrated Pest Management (IPM) practices, and employee safety training were covered as well as other aspects germane to preserving and protecting current water quality and related environmental issues. More than 75 nurseries were surveyed and given the opportunity to participate in future training at Oklahoma State Univ. Results indicated that nurseries have not fully implemented many BMPs, but have adopted fundamental IPM approaches. The stage is set for the implementation of the next phase of expansion and refinement into ecologically based programs such as propagation and sale of low pesticide input plant materials, improved cultural practices, and the integration of environmentally sound management approaches. As an example, many growers are in the process of phasing out calendar-based pesticide application programs in favor of aesthetic and/or economic threshold-driven pesticide spray programs.

Long-Term (15 Years) Results of NPS Controls in an Agricultural Watershed upon a Receiving Lake's Water Quality

1993 ◽  
Vol 28 (3-5) ◽  
pp. 441-449 ◽  
Author(s):  
Paul J. Garrison ◽  
Timothy R. Asplund
Keyword(s):  
Water Quality ◽  
Structural Changes ◽  
Soil Phosphorus ◽  
Water Clarity ◽  
Management Control ◽  
Agricultural Watershed ◽  
Control Measures ◽  
Phosphorus Loading ◽  
Phosphorus Concentration ◽  
White Clay

Nonpoint source controls were installed in a 1215 ha agricultural watershed in northeastern Wisconsin in the late 1970. Changes were made in handling of animal wastes and cropping practices to reduce runoff of sediment and nutrients. Modelling results predicted a reduction in phosphorus runoff of 30 percent. The water quality of White Clay Lake has worsened since the installation of NPS controls. The lake's phosphorus concentration has increased from a mean of 29 µg L−1 in the late 1970s to 44 µg L−1 in recent years. Water clarity has declined from 2.7 to 2.1 m and the mean summer chlorophyll levels have increased from 9 to 13 µg L−1 with peak values exceeding 40 µg L−1. Increased phosphorus loading is not the result of elevated precipitation but instead the failure of the control measures to sufficiently reduce P loading. Most of the effort was placed on structural changes while most of the P loading comes from cropland runoff. Further, soil phosphorus concentrations have increased because of artificial fertilizers and manure spreading. The White Clay Lake experience is discouraging since the majority of the polluters in this watershed utilized some NPS control practices, including 76 percent of the farms which installed waste management control facilities.

Pesticide Contamination of Groundwater in Virginia: BMP Impact Assessment

1993 ◽  
Vol 28 (3-5) ◽  
pp. 379-387 ◽  
Author(s):  
S. Mostaghimi ◽  
P. W. McClellan ◽  
R. A. Cooke
Keyword(s):  
Water Quality ◽  
Land Use ◽  
Best Management Practices ◽  
Water Samples ◽  
Management Practices ◽  
Water Quality Monitoring ◽  
Pesticide Contamination ◽  
Cropping Patterns ◽  
Creek Watershed ◽  
Surface And Groundwater

The Nomini Creek Watershed/Water Quality monitoring project was initiated in 1985, as part of the Chesapeake Bay Agreement of 1983, to quantify the impacts of agricultural best management practices (BMPs) on improving water quality. The watershed monitoring system was designed to provide a comprehensive assessment of the quality of surface and groundwater as influenced by changes in land use, agronomic, and cultural practices in the watershed over the duration of the project. The primary chemical characteristics monitored include both soluble and sediment-bound nutrients and pesticides in surface and groundwater. Water samples from 8 monitoring wells located in agricultural areas in the watershed were analyzed for 22 pesticides. A total of 20 pesticides have been detected in water samples collected. Atrazine is the most frequently detected pesticide. Detected concentrations of atrazine ranged from 0.03 - 25.56 ppb and occurred in about 26 percent of the samples. Other pesticides were detected at frequencies ranging from 1.6 to 14.2 percent of all samples collected and concentrations between 0.01 and 41.89 ppb. The observed concentrations and spatial distributions of pesticide contamination of groundwater are compared to land use and cropping patterns. Results indicate that BMPs are quite effective in reducing pesticide concentrations in groundwater.

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