中文摘要：

针对平原区城镇化背景下水系减少及连通受阻等下垫面变化引起的洪涝加剧问题,综合考虑水系结构和水力特性等因素,建立满足行洪排涝需求的平原水系连通度量方法,并以浙东沿海平原河网区为例,分析了城镇化下平原水系特征变化及其对河网连通度的影响。结果表明：1近20a来研究区水系数量和结构复杂性均存在不同程度的衰减,河网密度和水面率分别减少20%和30%左右,水系尤其是低等级河道的减少导致河网结构趋于骨干化;2河网连通度受水面率等数量特征和水系空间连接结构的共同影响,在水系数量持续减少情况下,整个河网连通度呈现先减少后增加的趋势,说明了骨干河道工程对水系空间结构特征的优化,可缓解水系减弱对河网连通的负面效应;3建立的河网连通度方法合理反映了水系数量和结构变化下的河网连通度演变规律,以及水系变化下区域排涝能力的空间差异特征,具有操作性强特点。

英文摘要：

Change of river system and its impact on flood is one of the hot spots in hydrological studies especially in plain river network region. In the present study, river structure and river network connectivity was analyzed in the coastal areas of East Zhejiang Province under the rapid urbanization. The result showed that drainage density and water surface rates were declined by 20% and 30% respectively during the past 20 years, and that drainage channel was in a more simple way due to the decline in river. The river network connectivity was evaluated based on the hydraulic resistance and Shortest Path Analysis, and the result indicated that river connectivity showed an increasing trend after the first reduction while the river system had a monotonic decreasing, and result from the construction of main channel which would decrease the negative impact of water debilitating on flood risk. The above assessment method was successfully applied to the study area and provided a feasible and effective way to analyze the change and spatial difference in the river connectivity.