辽宁省降雨变化对海绵城市低影响开发雨水系统建设的影响

Influence of variation in precipitation on the construction of a low-impact-development rain-water system for sponge city in Liaoning province

利用辽宁省50个气象站1956—2016年逐日降雨量资料,分析了辽宁省海绵城市低影响开发雨水系统建设首要控制目标——年径流总量控制率的分区、分区与降雨的关系,同时分析了降雨的变化特征,并研究了降雨变化对年径流总量控制率分区稳定性的影响。结果表明:辽宁省在1956—2016年、1956—1985年、1987—2016年3个时段的年径流总量控制率的分区整体呈现辽宁西部、东北部为II区,辽宁省中部、东部和沿海地区为III区,东港周围地区为V区,其余地区为IV区。其差异主要集中在辽宁省中部和东北部地区;辽宁省年径流总量控制率分区的设计降雨量(分区等级)与暴雨比例、中雨比例和暴雨总量关系密切,相关系数大部分通过0.01显著性检验,占总站点的78%,但与大雨总量基本无关;年径流总量控制率的分区受降雨变化影响而存在不稳定区域,主要分布在辽宁的中部、西部、北部以及丹东的南部(丹东和东港),其中,分区变更次数达到5次以上(含5次)的地区,建议年径流总量控制率分区选择出现过的最高等级,其余分区变更次数的地区的分区等级可选取出现频率最高的等级;因辽宁省的降雨存在10 a左右的周期变化,建议在海绵城市低影响开发雨水系统建设中以年径流总量控制率及其对应的设计降雨量为参考的设计参数每10 a进行一次修订。

Based on the historical daily precipitations at 50 national meteorological stations in Liaoning province from 1956 to 2016,the main control targets to the low-impact-development rain-water system for sponge city were investigated.The study includes the regional division of the detailed volume capture ratio to annual rainfall runoff and its relation with the precipitation,temporal variation of precipitation and its effects on the stability of the regional division of the detailed volume capture ratio to annual rainfall runoff.The results show that according to the regional division of detailed volume capture ratio of annual rainfall runoff in Liaoning province in 1956-2016,1956-1985 and 1987-2016,the western and northeastern Liaoning province belong to the second division,the eastern and coastal areas of Liaoning province are the third,the region around Donggang is the fifth,and the rest of the region is the fourth.The difference mainly occurs in the central and northeastern part of Liaoning province.A close relationship exists across rainstorm or moderate rain ratio,amount of rainstorm and the design rainfall for the regional division of detailed volume capture ratio of annual rainfall runoff,with the correlation coefficient test passing 0.01 of significance level,and 78% of the total measurement sites pass the test.No relationship is found with heavy rainfall.Changes of the regional division of detailed volume capture ratio of annual rainfall runoff exist due to the variation of precipitation.These regions mainly distribute in the central,western and northern parts of Liaoning province and southern Dandong （including Dandong and Donggang）.Division revision to their historical highest level should be adopted in the areas with a number of divisional changes no less than 5 times.The regions with a number of divisional changes less than 5 times should choose the historical most frequent level.As the precipitation in Liaoning province has a 10-year periodical variation,a revision of sponge city master plan should be advised every 10-year in the construction of a low-impact-development rain-water system for sponge city,based on the design rainfall of detailed volume capture ratio of annual rainfall runoff.