Study Of River Health Assessment Methodology Of Liaohe River Protected Areas

The investigations and identifications of aquatic organisms are the basis of the assessment of river ecosystem health. Macrozoobentho is one of the most widely distributed species in river ecological environment,and it is a kind of invertebrates and has complex groups. Macrozoobenthos is also considered a necessary part of the study of river ecosystem health and an important part of the ecological cycle. The Benthic-Index of Biotic Integrity(B-IBI) which is based on the identification of the Macrozoobenthos is widely used for the assessment of river ecosystem health. However, B-IBI Index algorithm has many problems, including overestimates the true variance of the observed variables and ignores the interactions of other variables, etc. In this paper, we used the structural equation modeling(SEM) and built the B-IBI-SEM river ecosystem health evaluation model based on the Index algorithm of B-IBI to assess the main stream of Liaohe River protected areas, for the improvement of the traditional B-IBI Index algorithm and conducting a more reasonable assessment of river ecosystem health of the main stream of Liaohe River protected areas. The main contents and results of this paper are as follows:(1) This paper conducted the identification of the Macrozoobenthos which was obtained from the sediment samples from a total of 30 sampling sites of the main stream of Liaohe River protected areas, and we identified a total of 47 kinds of Macrozoobenthos, most of which were the fouling resistant species.(2) At the beginning of modeling, the selections of the reference points and the damage points and the primary selections of biological indicators primaries was the first step, then the biological indicators was selected a second time by color discriminant matrix. The second selections of biological indicators primaries mainly used the reliability test、the validity test and the discriminantory analysis etc. After the selections, the Sihehuirukou sampling sit was selected as the reference point, and 10 biological candidate indicators that included the total number of taxa etc. were selected for the later modeling.(3) According to the principles of Structural Equation Modeling, the modeling process was carried out on the basis of traditional B-IBI assessment model. The B-IBI-SEM assessment model was constructed and amended at the upstream of the main stream of Liaohe River protected areas, then the model was built successfully. In order to verify the stabilization of the model, it is needed to use the downstream dates to verify the model. At last, the stable B-IBI-SEM model was obtained, that is B-IBI-SEM scores =(0.05K1+0.39K2-0.01 K3)+(-1.26K4-1.31K5)+(0.15K6+0.23K7)+ 0.41.(4) According to the B-IBI-SEM assessment model, the ecosystem health of the main stream of Liaohe River protected areas was assessed. Results indicated that different river sections of the main stream of Liaohe River protected areas mainly showed sub-health state and general state. The assessment results can objectively reflect the ecological status of the main stream of Liaohe River protected areas.