Study on the minimum ecological water requirement of Alashan bay based on grey association analysis and principal component analysis

It is one of the current hotspot subjects that study on the ecological and environmental water requirement in the world. The research was based on grey association analysis method and principal component analysis method, and took Alashan bay as an example. The results showed that although the two methods were based on different theories, the analysis conclusions were consistent. The quantity of the Larus Relictus nests and the zoobenthos species were highly correlated with the water level. They could be regarded as the indicator of the ecological environment. According to the maximum value principle, the minimum ecological water requirement is 1.9×106 m3 in the region of Alashan bay.