4.3. Ecological restoration scenarios
Average sustainability value for each month in 2006 is lower than 0.618 (Figure 6), which indicates ecological restoration is necessary at the same period.
4.3.1. Scenario 1 - Water replenishment
Table 7 summarizes the required quantity of water replenishment. The water quantity needed to achieve the desired water quality is almost three times larger than that required to reach the sustainability goal. The aforementioned methods chose the maximum value as the final water quantity to satisfy the requirements of water quality and ecological sustainability. This selection reflects the real demands. In this scenario, water quality goal is a constraint which can be met by reducing the concentration of three major indicators, i.e. CODMn (Chemical Oxygen
Demand), TN (Total Nitrogen) and TP (Total Phosphorous) by dilution.