Identifying Watershed Regions Sensitive to Soil Erosion and Contributing to Lake Eutrophication--A Case Study in the Taihu Lake Basin (China).

Chen Lin,Bin He,Ronghua Ma

doi:10.3390/ijerph13010077

Abstract

Taihu Lake in China is suffering from severe eutrophication partly due to non-point pollution from the watershed. There is an increasing need to identify the regions within the watershed that most contribute to lake water degradation. The selection of appropriate temporal scales and lake indicators is important to identify sensitive watershed regions. This study selected three eutrophic lake areas, including Meiliang Bay (ML), Zhushan Bay (ZS), and the Western Coastal region (WC), as well as multiple buffer zones next to the lake boundary as the study sites. Soil erosion intensity was designated as a watershed indicator, and the lake algae area was designated as a lake quality indicator. The sensitive watershed region was identified based on the relationship between these two indicators among different lake divisions for a temporal sequence from 2000 to 2012. The results show that the relationship between soil erosion modulus and lake quality varied among different lake areas. Soil erosion from the two bay areas was more closely correlated with water quality than soil erosion from the WC region. This was most apparent at distances of 5 km to 10 km from the lake, where the r2 was as high as 0.764. Results indicate that soil erosion could be used as an indicator for identifying key watershed protection areas. Different lake areas need to be considered separately due to differences in geographical features, land use, and the corresponding effects on lake water quality.

Highlights

Anthropogenic activities and land use/cover change (LUCC) have greatly increased soil erosion and non-point source (NPS) pollution loading in many watersheds, which can have significant impacts on lake ecosystems [1,2,3]
As soil erosion is a critical factor for watershed nutrient loss and lake eutrophication, we focused on the relationship soil erosion modulus eutrophication areasbyacross a temporal where Rrc pλqbetween is the baseline reflectance of each and band,lake which had been corrected
The Western Coastal region (WC) region was eroded slightly when compared with the other regions, and the Zhushan Bay (ZS) region had the within the 12 year period (Figure 2) and showed clear differences between lake areas

Summary

Introduction

Anthropogenic activities and land use/cover change (LUCC) have greatly increased soil erosion and non-point source (NPS) pollution loading in many watersheds, which can have significant impacts on lake ecosystems [1,2,3]. Lake water deterioration can have serious effects on the health of local inhabitants. There is a critical need to study the relationship between watershed pollution and lake water quality for the purpose of aquatic environment protection. The delineation of the watershed region sensitive to lake ecosystem deterioration is a fundamental issue in watershed environment management [5,6,7]. Many studies have directly or indirectly examined the response of lake ecosystems to changes in watershed land use. Lake nutrient concentrations and primary production have been associated with agricultural nutrient loading [8,9], while dissolved organic carbon (DOC), total suspended

Methods

Results

Discussion

Conclusion