扎龙湿地水量平衡分析

对扎龙湿地1956-2000年的水循环要素特征进行分析,并计算了扎龙湿地在自然条件下的水量平衡关系。结果表明,扎龙湿地在研究时段内蓄水量总体呈下降趋势,蓄水量平均每年减少16.8×106m₃。大气降水是扎龙湿地的主要水源,占总来水量的61.5%,其次是上游乌裕尔河和双阳河的河川径流量,占36.5%,区间径流很小,只占2.0%;扎龙湿地的主要耗水项是蒸散(发),占总耗水的74.4%,其次是渗漏,占14.5%,下游出流只占11.1%。

Analysis of Water Balance in Zhalong Wetland

Zhalong Wetland is a floodplain wetland with an area of 2 100km₂.The main source rivers are Wuyur and Shuangyang rivers.The surface of the wetland is very flat except some small ridges.It is composed of a wide central area covered by flush reeds and surrounded by lakes.A root and humus layer of reed with a depth of 1-2m covers a deeply embedded clay layer in the wetland.The maximum depth of water in the central area of the wetland is about 2m.The area of water surface accounts for 70% of the total area of the nature reserve in an average hydr-ological year. Wetlands are now recognized as one of the world's most productive ecosystems which through their functions provide goods and services for the health,safety and welfare of human populations.These functions include groundwater discharge and recharge,sediment trapping,flood storage,water quality improvement and fishery and wildlife habitat.Unfortunately,wetland loss has occurred at devastating rates throughout the world over the past two centuries due to climate change and human activities.In order to conduct a successful wetland restoration and sustainable management of wetlands,understanding and quantifying the hydrological processes are vital.The most common approach for determining wetland hydrology is to calculate water balance based on all sources and sinks to the system.Water balance for the Zhalong wetland was calculated for the period of 1956-2000.Firstly,the methods of accumulated difference is uesd to analyze the characteristics of water cycling elements including precipitation,evapotranspiration and inflow.Then,water balance was caculated in Zhalong wetland in light of its nanual condition for the period 1956-2000.The results show that the water storage of Zhalong wetland had a trend of slightly decrease by an annual average of 16.8×106m3.The annual average water inputs into Zhalong wetland were as follows:61.5% from precipitation,36.5% from upstream inflow,and 2.0% from upland runoff;the annual average water outputs from Zhalong wetland consisted of 74.4% from evaporation and evapotranspiration,14.5% from estimated seepage,and 11.1% from down-steram outflow.Finally,an effect analysis of the hydrological change to Zhalong wetland ecosystem was conducted.The results show that both quantity and qulity of the biology such as birds,fishes and reed marsh were degradated in the last decades.The paper also shows that additional water are required to restore the wetland ecosystem.Diverting water from Nenjiang River maybe a feasible measure to solve this problem,however,more work should be done for the reasonable wetland water resouces management.