Research On Ecological Water Supplementary Scheme And Impact Of Sanhuanpao Wetland

Wetlands,known as the"kidney of the earth",play an irreplaceable role in improving water quality,climate and nurturing animals and plants.However,due to the impact of human production and life,causes the rapid reduction of wetland area,the gradual degradation of wetland vegetation,the destruction of wetland for suitable habitat of waterfowl,and the gradual degradation of wetland ecosystem,wetland ecological restoration is imminent.In this paper,the Sanhuanpao Wetland in Sanjiang Plain of Heilongjiang Province is the research area,and its degradation characteristics and causes are explored.The objectives of wetland restoration are determined.The ecological water demand of wetland is calculated by hydro-ecological method and model numerical simulation,and the effect of water replenishment is analyzed according to the results of field flow evolution model.The research results have a practical guiding significance for wetland recharge and restoration.The main conclusions are as follows:(1)During the 36 years from 1980 to 2015,the land use area of Sanhuanpao National Nature Reserve changed as follows:marsh wetland decreased by 32.0%,cultivated land increased by 32.0%,and water area changed little.The vegetation changes in the reserve are as follows:the herbaceous marsh vegetation in the reserve had decreased from 94.4%to 49.0%,the marshy meadow had increased from 1.0%to 16.5%,the typical meadow had increased slightly,and the cultivated land area has increased from 4.5%to 27.0%.According to the vegetation succession law of Sanjiang Plain,the wetland vegetation in the protected area is degraded.(2)Two methods,hydro-ecological and model simulation,were used to calculate wetland ecological water demand.The ecological water requirement of wetland in reserve is calculated by hydro-ecological method mainly includes four parts:evaporation of water surface,transpiration of vegetation,soil water demand and water demand of biological habitats.The calculation results are as follows:the ecological water demand of wetland in April-October under the suitable restoration target is 201.7 million m~3,of which the water consumption is147.4 million m~3 and non-consumption is 54.3 million m~3.The total ecological water requirement of wetland is 217.8 million m~3 and the water storage is 162.4 million m~3,of which the water consumption is 55.4 million m~3.The difference between the two methods is 8.0%,mainly due to the deviation caused by the change of micro-topography and wetland area over time.The model simulation can better reflect the actual water demand of wetland.Finally,the calculated value of the model simulation is used as the result of wetland ecological water demand.(3)The final ecological water requirement of wetland is calculated by using the model simulation results.On this basis,the artificial supplementary water of wetland is calculated.The supplementary water under 50%guarantee rate is 13.3 million m~3,under 75%guarantee rate is 25.6 million m~3 and under 95%guarantee rate is 57.4 million m~3.(4)The effect of wetland recharge was analyzed from three aspects:the change of wetland area,the change of wetland vegetation and the change of rare waterfowl.The simulation results show that the submerged area in the reserve is 200.5 km~2,accounting for 72.4%of the reserve area,and the simulation results can reach the restoration goal.Continuous supplementation of appropriate water to the wetland will significantly improve the hydrological conditions of the wetland,effectively increase the wetland area,and guide the forward succession of regional vegetation.At the same time,it also provides a good habitat for rare waterfowl in the region,increases species richness,and makes the wetland ecosystem in the reserve more stable.