Identifying critical source areas of non-point source pollution to enhance water quality: Integrated SWAT modeling and multi-variable statistical analysis to reveal key variables and thresholds

Fang, Shubo; Deitch, Matthew J.; Gebremicael, Tesfay G.; Angelini, Christine; Ortals, Collin J

doi:10.1016/j.watres.2024.121286

Cited by 8 publications

(1 citation statement)

References 57 publications

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“…Vegetation cover affects the underlying surface characteristics, hydrological processes, and nutrient cycling, further influencing the storage and retention capacity of nutrients in different land use types [62]. Woodlands and shrubs can absorb and sequester nutrients to some extent, which helps mitigate the effects of pollution due to higher vegetation cover and less anthropogenic disturbance [7,63]. In contrast, agricultural land is plowed year-round, often exhibiting low vegetation cover or even bare ground.…”

Section: Cost-effectiveness Of Bmp Scenariosmentioning

confidence: 99%

Optimizing Non-Point Source Pollution Management: Evaluating Cost-Effective Strategies in a Small Watershed within the Three Gorges Reservoir Area, China

Chang,

Wang,

Liu

et al. 2024

Land

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Non-point source (NPS) pollution poses a significant threat to the water environment, yet controlling it at the watershed scale remains a formidable challenge. Understanding the characteristics and drivers of nitrogen (N) and phosphorus (P) outputs at the watershed scale, along with identifying cost-effective best management practices (BMPs), is crucial for effective pollution control. In this study, we utilized the Wangjiaqiao watershed within the Three Gorges Reservoir Area (TGRA) as a case study to explore the characteristics of N and P load outputs and their dominant drivers by combining the SWAT model and a geographic detector. Based on our analysis of N and P loads within the watershed, we employed the entropy weight method to evaluate the reduction efficiency and cost-effectiveness of 64 BMP scenarios, encompassing seven measures (vegetative filter strips, parallel terraces, 10% fertilizer reduction, 30% fertilizer reduction, residue cover tillage, grass mulching, and returning farmland to forest) and their combinations. Our findings revealed the following: (1) spatial heterogeneity in NPS loads within the watershed, primarily influenced by land use, fertilizer application, and surface runoff, with interactive enhancement effects among driving factors; (2) the differential effectiveness of BMPs at the watershed level, with structural measures, particularly terracing, exhibiting higher efficacy and achieving reduction rates of 28.12% for total nitrogen (TN) and 37.69% for total phosphorus (TP); the combined BMPs showed improved reduction efficiency, but not merely additive; and (3) in terms of cost-effectiveness, 30% fertilizer reduction emerged as the most beneficial among the individual measures. Moreover, a combination of vegetative filter strips, parallel terraces, and 30% fertilizer reduction demonstrated significant improvements in TN and TP reductions (48.05% and 61.95%, respectively), suggesting their widespread applicability. Overall, our study provides insights into developing a cost-effective BMP strategy for the Wangjiaqiao watershed and offers valuable guidance for NPS pollution management in similar small watersheds within the TGRA.

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Section: Cost-effectiveness Of Bmp Scenariosmentioning

confidence: 99%

Optimizing Non-Point Source Pollution Management: Evaluating Cost-Effective Strategies in a Small Watershed within the Three Gorges Reservoir Area, China

Chang,

Wang,

Liu

et al. 2024

Land

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Modification and testing of SWAT for paddy field water consumption and yield

Chen,

Li,

Luo

et al. 2024

River

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SWAT model is one of the primary tools for assessing irrigation district water management and water‐saving measures. However, its incapacity to consider the diverse growth and water requirements of paddy during various growth stages, as well as the insufficient availability of external water sources. This study introduces the Penman‐Monteith equation and Jensen model into the SWAT framework, setting crop coefficients, crop base coefficients, and growth stage sensitivity indices based on the different growth stage. Additionally, modifications are made to the external water source available for irrigation and paddy field leakage modules, establishing a distributed agricultural hydrological model suitable for accurately simulating water balance elements and paddy yield in multi‐source irrigation districts. The Yangshudang watershed in the Zhanghe irrigation district is chosen for the evaluation of the modified model's simulation performance, with a quantitative assessment of water‐saving and yield‐increasing effects. The results demonstrate that the modified model effectively meets the requirements for simulating paddy evapotranspiration of various growth stages, yield, agricultural irrigation water consumptions, and runoff, exhibiting a notable enhancement in performance. As two common water‐saving measures in irrigation areas, intermittent irrigation and irrigation district renovation were used as two water‐saving scenarios in the simulation of the modified SWAT model. Under intermittent irrigation, the watershed experiences a 6.58% reduction in net irrigation water use. In the scenario with irrigation district renovation, the water resources in the watershed are utilized more efficiently. The modified model from this study can be applied for assessing the synergistic effects of irrigation district water‐saving and yield‐increasing measures, providing crucial insights for the formulation of irrigation district water‐saving strategies and water resource optimization plans.

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A review on curbing non-point source pollution in watershed—the answer lies at the root

Ding,

Song,

et al. 2024

Environ Dev Sustain

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Identifying critical source areas of non-point source pollution to enhance water quality: Integrated SWAT modeling and multi-variable statistical analysis to reveal key variables and thresholds

Cited by 8 publications

References 57 publications

Optimizing Non-Point Source Pollution Management: Evaluating Cost-Effective Strategies in a Small Watershed within the Three Gorges Reservoir Area, China

Optimizing Non-Point Source Pollution Management: Evaluating Cost-Effective Strategies in a Small Watershed within the Three Gorges Reservoir Area, China

Modification and testing of SWAT for paddy field water consumption and yield

A review on curbing non-point source pollution in watershed—the answer lies at the root

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