Identification of Critical Source Areas (CSAs) and Evaluation of Best Management Practices (BMPs) in Controlling Eutrophication in the Dez River Basin

Hadi Babaei,Sajjad Ahmad,Mohammad Nazari-Sharabian,Moses Karakouzian

doi:10.3390/environments6020020

Hadi Babaei, Sajjad Ahmad + Show 2 more

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https://doi.org/10.3390/environments6020020

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Abstract

Best Management Practices (BMPs) are commonly used to control pollution in the river basins. Prioritization of BMPs helps improve the efficiency and effectiveness of pollution reduction, especially in Critical Source Areas (CSAs) that produce the highest pollution loads. Recently, the Dez River in Khuzestan, Iran, has become highly eutrophic from the overuse of fertilizers and pesticides. In this basin, dry and irrigated farming produce 77.34% and 6.3% of the Total Nitrogen (TN) load, and 83.56% and 4.3% of the Total Phosphorus (TP) load, respectively. In addition, residential, pasture, and forest land uses together account for 16.36% of the TN and 12.14% of the TP load in this area. The Soil and Water Assessment Tool (SWAT) was implemented to model the Dez River basin and evaluate the applicability of several BMPs, including point source elimination, filter strips, livestock grazing, and river channel management, in reducing the entry of pollution loads to the river. Sensitivity analysis and calibration/validation of the model was performed using the SUFI-2 algorithm in the SWAT Calibration Uncertainties Program (SWAT-CUP). The CSAs were identified using individual (sediment, TN, TP) and combined indices, based on the amount of pollution produced. Among the BMPs implemented, the 10 m filter strip was most effective in reducing TN load (42.61%), and TP load (39.57%).

Highlights

With population growth, industrialization, and climate change, water management is a major global challenge [1]
In order to reduce pollution entry into the Dez River, the following Best Management Practices (BMPs) were implemented: point source pollution elimination; implementation of 5 m and 10 m filter strips in residential and agricultural lands; a 20% and 50% reduction in livestock grazing in the basin; and management of the main river channel
In order to find the most effective parameters affecting the yields of runoff, sediment, Total Nitrogen (TN), and Total Phosphorus (TP), the sensitivity analysis was performed on each variable separately

Summary

Introduction

Industrialization, and climate change, water management is a major global challenge [1]. In arid and semi-arid areas, this challenge is even more severe [2]. Water pollution further reduces the availability of already stressed water resources [3]. Due to water scarcity in Iran, the quality of water resources has become one of the major concerns of the country [4]. This situation necessitates the development of managerial strategies to identify critical source areas (CSAs) that contribute most to pollutant loading. Pollution sources are mainly classified into two categories of point and non-point sources

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Conclusion