降雪对乌鲁木齐市海绵城市LID设施的影响

Impact of snowfall on LID facilities for sponge city of Urumqi

为研究冬季降雪对海绵城市LID(low impact development)设施的影响,以乌鲁木齐市某城市主干道为例,借助SWMM模拟软件建立海绵化改造模型,讨论模型各重要参数的取值方式,进行降雪及融雪模拟,分析降雪在不同模拟环境下对道路海绵化改造的影响。结果显示:在冬季降雪期,蒸发速率对模型的影响较大,在没有当地准确的蒸发速率资料时,推荐使用基于Hargreaves方程的公式法进行模拟分析。利用SWMM模拟冬季融雪期径流过程,各汇水区域的积雪处理方式对模拟结果影响很大,应合理分析并结合当地实际情况进行设定。模拟结果表明:若乌鲁木齐市冬季降雪全部堆积在道路两旁生物滞留设施上,可利用融雪量达10.6万m 3,能够减轻乌市的水资源压力。研究成果对积雪量较大而水资源短缺地区海绵城市的建设具有工程上的参考价值。

In order to study the impact of snowfall in winter on the LID(low impact development)facilities for the sponge city,a sponge transformation model is established by means of SWMM simulation software,and then the value-taking modes of all the important parameters of the model are discussed herein,while the simulations of snowfall and snow melting are carried out and then impacts from different simulated environments on the sponge transformation of road are analyzed.The result shows that during snowfall in winter,the impact of the evaporation rate on the model is larger,for which it is recommended to make the simulative analysis with the Hargreaves equation-based formula method when no any accurate data of local evaporation rate is available.For simulating runoff process during snowmelt period in winter with SWMM,the modes for the treatment of accumulated snow in all the catchment areas have large impacts on the simulation result,which must be reasonably analyzed and set in accordance with the actual local conditions.The simulation result indicates that if all the snowfalls in winter in Urumqi are piled up on the bio-retention facilities on both the sides of road,the available snowmelt amount can reach 106 000 m 3 and the pressure on water resources in Urumqi can be alleviated as well.The study result has an engineering referential value for the construction of sponge city in the region with larger accumulated snow and shortage of water resources.