洪涝风险胁迫下登封市蓝绿基础设施网络构建研究

Construction of blue-green infrastructure network in Dengfeng City under flooding risk stress

为提高城市生态防洪韧性,构建蓝绿基础设施网络,依据登封市2021年4月Landsat遥感影像数据,通过降雨-径流水文模型分析枯水月、平水月以及丰水月的淹没范围,并将分析结果转化为电阻面纳入潜在生态廊道的识别与构建中,利用连通性分析和电路理论筛选匹配登封市的最佳扩散距离和廊道“宽度”,并综合分析廊道关键障碍点、夹点以及易涝区现状条件,提出了登封市蓝绿基础设施网络的构建策略。结果表明:1)14个汇水区内的林地在枯水月、平水月以及丰水月的平均雨洪消减率逐渐降低,分别为94.42%、80.85%、47.46%;2)在丰水月随着雨量增加林地逐渐成为在建设用地之下的第二大产流体,导致9.10 km^(2)的建设用地处于淹没风险区。位于洪涝高压区的告城镇受淹面积由枯水月的0.29 km^(2)扩大至丰水月的3.13 km^(2)。3)识别出26个重要源地、4个一般源地、56条潜在廊道、107处关键障碍点以及14处重要夹点。其中登封市东南地区关键廊道较窄且电流密度较高,多处重要夹点毗邻建设用地,且每条廊道均存在多个关键障碍点,多为城镇建筑、交通道路及废弃矿坑。4)结合研究结果,提出恢复颍河下游河道河岸缓冲带、增设河漫滩、拓宽河道行洪断面等生态策略以强化蓝绿空间融合,借助绿道与河流走廊的交织缝合串联各地坑塘水库,形成安全稳固的“化整为零、分散排水”的雨洪调蓄空间格局。本研究可为建设登封市蓝绿基础设施网络提供参考。

In order to improve urban ecological flood protection resilience and build a blue-green infrastructure network,the rainfall-runoff hydrological model was adopted to analyze the inundation range of dry month,normal month and wet month based on the Landsat remote sensing image data of Dengfeng City in April 2021.The inundation identification results were transformed into resistive surfaces and input into the identification and construction of potential ecological corridors.The connectivity analysis and circuit theory were used to screen and match the optimal diffusion distance and corridor"width"in Dengfeng City,and the corridors were comprehensively analyzed based on the key obstacles,pinch points and the current conditions of flood-prone areas.Finally the construction strategy of the blue-green infrastructure network in Dengfeng City was proposed.The result showed that:1)The average rainwater reduction rates of forest land in the 14 catchment areas in dry,normal,and wet month gradually decreased by 94.42%,80.85%,and 47.46%,respectively.2)With the increase of rainfall in the wet month,forest land gradually became the second largest runoff type under construction land,which caused 9.10 km^(2) of construction land to be in the inundation risk area,and the inundated area of Gaocheng located in the flood high pressure area in the dry month expanded from 0.29 km^(2) to 3.13 km^(2).3)A total of 26 important sources,4 general sources,56 potential corridors,107 key obstacle points and 14 important pinch points were identified.Among them,the key corridors in the southeastern part of Dengfeng City were narrower and had higher current density.Many important pinch points were adjacent to the construction land,and each corridor had several key obstacle points,most of which were urban buildings,traffic roads and abandoned mines.This study proposed to strengthen the integration of blue and green spaces through ecological strategies such as restoring the river bank buffer zone,adding floodplains,and widening the flood section of the river in the lower reaches of the Ying River.It also proposed to form a safe and stable spatial pattern of rain and flood regulation and storage that is“dividing into parts and dispersion drainage”.This research provided reference for the construction of blue-green infrastructure network in Dengfeng City.