Abstract: In an attempt to restore the ecology of karst wetlands, numerical simulation was conducted to calculate the water demand of wetland. We employed Mike21 for 2D numerical calculation of water demand and water replenishment scheme of Huixian wetland in the condition of multi-year average water level. By obtaining the correlation of internal water level between Liangfeng Station and Huixian wetland, we identified that the multi-year average water level of Huixian wetland is 148.86 m. Under this water level, the ecological water demand and environmental water demand of the wetland are 3.87×10⁶ m³ and 3.67×10⁶ m³ respectively, resulting in an overall water demand of 3.87×10⁶ m³. Through analysis of surface water system, we determined the water replenishment route from the Huixian River through the ancient Guiliu Canal at a flow rate of 5 m³/s. Simulation results demonstrate that the water surface rate of the wetland remains within the normal range after replenishment.

Key words: wetland water demand, water replenishment scheme, Mike21 model, numerical simulation, Huixian karst wetland