Ecological River Health Assessments Using Chemical Parameter Model and the Index of Biological Integrity Model

Kwang-Guk An,Jang Hara,Md Mamun

doi:10.3390/w11081729

Abstract

River health is one of the important issues today because of various threats by multiple anthropogenic stressors that have long-term impacts on the physical habitats, biodiversity, ecological functions, and their services. The main objectives of this study is to diagnose the chemical and biological river health in the watershed of Geum River with regard to the chemical regimes (N, P) and fish community using multi-metric chemical pollution index (CPI), and the index of biotic integrity model (IBI), respectively. The empirical models of sestonic chlorophyll, nutrients (N, P), and nutrient ratios of N:P indicated that the watershed, including all sampling sites, was a phosphorus-limited system. Analysis of fish trophic and tolerance guilds showed that the omnivore fish species and tolerant fish species were dominant in the watershed, while the sensitive fish species decreased downstream because of nutrient enrichments (such as TN, TP) and organic matter pollutions (such as BOD, COD). The chemical model of CPI showed that 11 sampling sites were in the fair—good condition, and 8 sites were in poor—very poor condition. Species composition analysis indicated that Zacco platypus was most widely distributed in the watersheds and dominated the fish community. The biological health of the watershed, based on the multimetric IBI model, was in poor condition and was getting worse downstream. The degradation of the river health was matched with the chemical health and showed a decreased abundance of insectivores and sensitive fish species. The outcomes of the river health were supported by principal component analysis (PCA) and cluster analysis (CA) of fish model metrics and the physicochemical parameters. Overall, our study suggests that river health was directly influenced by the chemical pollutions of nutrients and organic matter inputs.

Highlights

River and streams provide multiple eco-services including clean water in sufficient quantity and quality for agricultural, industrial, and residential uses, act as a hotspot of aquatic, riparian, and migratory biota, and support fisheries and recreation for a human beings in a sustainable manner [1,2]
The purpose of this study is (a) to diagnose the chemical health of Geum River using chemical pollution index (CPI) multi-metric model; (b) to analyze the species composition, trophic and tolerance guilds and determine how are they correlated with water quality factors; (c) to evaluate the biological health using index of biotic integrity model based on fish community; (d) to predict the ecological health using artificial neural network model (ANN)
The concentration of of total phosphorus (TP) and total nitrogen (TN) was lower in G01–G10 sites, while it was higher in G11–G19 sites

Summary

Introduction

River and streams provide multiple eco-services including clean water in sufficient quantity and quality for agricultural, industrial, and residential uses, act as a hotspot of aquatic, riparian, and migratory biota, and support fisheries and recreation for a human beings in a sustainable manner [1,2]. Industrialization, and intensive agricultural farming the structure and function of the river and stream ecosystem are severely affected, which lead to the significant degradation of water quality and ecosystem integrity [3]. The assessment of ecological health in river and streams cannot be diagnosed directly because it is affected by their surrounding environments such as hydrology, water quality, physical form, riparian. Earlier studies on the diagnosis of stream and river health assessment have focused on the water quality factors [10]. Recent research pointed out that this method is not sufficient to determine the ecological health of the freshwater ecosystem [11]

Objectives

Methods

Results

Conclusion