Physicochemical water quality characteristics in relation to land use pattern and point sources in the basin of the Dongjin River and the ecological health assessments using a fish multi-metric model

Geon-Su Jang,Kwang-Guk An

doi:10.1186/s41610-016-0011-2

Abstract

Little is known about how chemical water quality is associated with ecological stream health in relation to landuse patterns in a watershed. We evaluated spatial characteristics of water quality characteristics and the ecological health of Dongjin-River basin, Korea in relation to regional landuse pattern. The ecological health was assessed by the multi-metric model of Index of Biological Integrity (IBI), and the water chemistry data were compared with values obtained from the health model. Nutrient and organic matter pollution in Dongjin-River basin, Korea was influenced by land use pattern and the major point sources, so nutrients of TN and TP increased abruptly in Site 4 (Jeongeup Stream), which is directly influenced by wastewater treatment plants along with values of electric conductivity (EC), bacterial number, and sestonic chlorophyll-a. Similar results are shown in the downstream (S7) of Dongjin River. The degradation of chemical water quality in the downstream resulted in greater impairment of the ecological health, and these were also closely associated with the landuse pattern. Forest region had low nutrients (N, P), organic matter, and ionic content (as the EC), whereas urban and agricultural regions had opposite in the parameters. Linear regression analysis of the landuse (arable land; AL) on chemicals indicated that values of AL had positive linear relations with TP (R 2 = 0.643, p < 0.01), TN (R 2 = 0.502, p < 0.05), BOD (R 2 = 0.739, p < 0.01), and suspended solids (SS; (R 2 = 0.866, p < 0.01), and a negative relation with TDN:TDP ratios (R 2 = 0.719, p < 0.01). Chemical factors were closely associated with land use pattern in the watershed, and these factors influenced the ecological health, based on the multimetric fish IBI model. Overall, the impairments of water chemistry and the ecological health in Dongjin-River basin were mainly attributes to point-sources and land-use patterns.

Highlights

Little is known about how chemical water quality is associated with ecological stream health in relation to landuse patterns in a watershed
Previous studies pointed out that water quality is degradated in the downstream regions, which are directly influenced by the wastewater treatment plants or agricultural crop-cultivation in the wide ranges of rice paddy (Seo et al 2001; Jung et al 2009; Seong and Park 2012)
Descriptions of study sites Nine sampling sites belong to three streams in the basin; four sites of site 1–site 4 belong to the Jeongeup Stream, three sites of S5–S7 belong to the Dongjin River, and the remaining two sites of site 8 and site 9 belong to the Gobu Stream

Summary

Introduction

Little is known about how chemical water quality is associated with ecological stream health in relation to landuse patterns in a watershed. The stream water is largely used by drinking water and agricultural irrigation along with partial use of industrial water For these reasons, previous studies pointed out that water quality is degradated in the downstream regions, which are directly influenced by the wastewater treatment plants or agricultural crop-cultivation in the wide ranges of rice paddy (Seo et al 2001; Jung et al 2009; Seong and Park 2012). Previous studies pointed out that water quality is degradated in the downstream regions, which are directly influenced by the wastewater treatment plants or agricultural crop-cultivation in the wide ranges of rice paddy (Seo et al 2001; Jung et al 2009; Seong and Park 2012) For these reasons, basin management is important for maintaining chemical water quality and the aquatic ecosystem

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