Today, let’s talk about ecological water replenishment

On June 2, the three-month 2023 Beijing-Hangzhou Grand Canal successfully completed its full-line water replenishment mission, with a total water replenishment of 926 million cubic meters, and the Zhanghe River was connected to the sea. The Beijing-Hangzhou Grand Canal is once again fully connected, and the ecological water replenishment has achieved remarkable results. Today, let's talk about ecological water replenishment.

1.What is ecological water replenishment?

Ecological water replenishment, in simple terms, is to restore or protect the local ecological environment through water replenishment. In professional terms, it means that by taking engineering or non-engineering measures, water is transferred to the damaged ecosystem due to the inability to meet the minimum ecological water demand, the water consumption of the ecosystem is supplemented, the destruction of the ecosystem structure and the loss of function are curbed, and the original self-regulating function of the ecosystem is gradually restored . Among them, ecological water demand refers to the amount of water required to maintain the balance and stability of the normal ecosystem and material cycle of rivers and lakes. Ecological water replenishment can not only increase the self-purification capacity of water bodies and alleviate water pollution, but also has important functions such as restoring water ecosystems, maintaining biodiversity , regulating local climate, and alleviating urban heat island effects .

Yongding River

2. Why do some rivers and lakes have insufficient ecological water needs?

Insufficient ecological water demand can be understood as "imbalance between income and expenditure", that is, "loss" of water resources in rivers and lakes. "Income" refers to ice and snow meltwater, natural precipitation, surface runoff, groundwater, local reservoir water, etc.; "Expenditure" refers to infiltration, evaporation, flow, human use, etc. When income is less than expenditure, there will be "loss", resulting in insufficient ecological water demand. Under water shortage conditions, many problems will arise in the ecological environment. Such as shrinking wetlands, reduced vegetation coverage, reduced biodiversity, eutrophication of water bodies, etc., which will affect the balance of the natural environment. Taking North my country as an example, the northern region has been short of water for a long time, especially the over-exploitation of water resources in the Huanghuaihai Basin in the 1980s and 1990s, which led to the drying up of rivers and lakes and siltation of river mouths. In addition, the water resource endowment conditions in North China are poor and the total amount of water resources is small. After large-scale development and utilization of groundwater, groundwater over-exploitation in North China has been serious. In 2019, the Ministry of Water Resources, the Ministry of Finance, the National Development and Reform Commission, and the Ministry of Agriculture and Rural Affairs jointly issued the "Action Plan for Comprehensive Management of Groundwater Overexploitation in North China", which clearly proposed to carry out ecological water replenishment and groundwater replenishment for the river and lake systems in Beijing, Tianjin and Hebei, while ensuring normal water supply.

Wuliangsuhai Lake

3.Is there a time requirement for replenishing water?

There is no strict time limit for ecological water replenishment. For example, during the Yellow River ice flood season, ecological water replenishment was carried out in Wuliangsu Lake, which not only reduced the pressure of ice flow on the Yellow River, but also met the ecological water demand of Wuliangsu Lake during the dry season. For example, before the main flood season, the Yangtze River Water Conservancy Commission discussed and deployed the pre-flood drawdown dispatching of important reservoirs, and reserved sufficient storage capacity in advance to welcome concentrated rainfall. At the same time, ecological dispatching of reservoirs such as the Three Gorges was carried out simultaneously, so that the water during the drawdown period could give full play to the comprehensive benefits of water replenishment and ecology.

4.What are the measures for ecological water replenishment?

Ecological water replenishment mainly includes engineering and non-engineering measures. Engineering measures mainly use artificial water conservancy facilities such as canals, reservoirs, and gates to replenish ecological water. It can better control the time and amount of water delivery and ensure the safety of water quality; non-engineering measures use natural river channels for water replenishment, which has the characteristics of low cost and small engineering volume. In practice, different options will be made by comprehensively considering the water replenishment situation and requirements.

Chaobai River

Ecological water replenishment is good, but it is not a one-time solution. We must be prudent in using water resources and remember not to waste water while diverting water for replenishment.