Development and preliminary application of a method to assess river ecological status in the Hai River Basin, north China

Abstract

The river ecosystem in the Hai River Basin (HRB), an important economic region in China, is seriously degraded. With the aim of river restoration in the HRB, we developed a method to assess the river's ecological status and conducted a preliminary application of the method.The established method was a predictive model, which used macroinvertebrates as indicator organisms. The river's ecological status was determined by calculating the ratio of observed to expected values (O/E). The method included ecoregionalization according to natural factors, and the selection of reference sites based on combinations of habitat quality and macroinvertebrate community. Macroinvertebrate taxa included Insecta, Crustacea, Gastropoda, and Oligochaeta, with 39 families and 95 genera identified in the HRB. The HRB communities were dominated by pollution tolerant taxa, such as Lymnaeidae, Chironomus, Limnodrilus, Glyptotendipes, and Tubifex. The average ShannonWiener index was 1.40 ± 0.5, indicating a low biodiversity. In the river length of 3.31 × 10 4 km, 55% of the sites were designated poor, with a bad ecological status. Among nine secondary river systems, Luan and Zi-ya had the best and worst river conditions, respectively. Only 17 reference site groups were selected for river management in the 41 ecoregions examined. This study lays the foundation for river restoration and related research in the HRB, and we anticipate further developments of this novel method.

Using Chironomus dilutus to identify toxicants and evaluate the ecotoxicity of sediments in the Haihe River Basin

“…The Haihe River Basin is in one of the most industrialized and urbanized regions in China. The rapid rate of urbanization, which increased from 18% in 1978 to 46% in 2009, has subjected river ecosystems to great stress, especially in the plain areas 22 . The population in the Haihe River Basin increased from 8.16 million in 1985 to about 180 million in 2014, and the industrial wastewater discharge increased from 0.33 billion tons to 2.37 billion tons in the same period.…”