植草沟草种选择对降雨径流调蓄效应的影响

Effect of grass species selection for grass swales on runoff regulation

【目的】探究不同草种对植草沟控制径流和渗水蓄水功能的影响,针对不同降水强度选择出更适合的植草沟草种,为海绵城市建设提供参考资料和理论依据.【方法】选用由大叶油草(Axonopus compressus)、百慕大草(Cynodon dactylon)、假俭草(Eremochloa ophiuroide)3种不同植物构成的植草沟进行小雨、大雨、暴雨3个降雨强度的模拟降雨观察试验,分析在不同降雨条件下,3种植草沟对径流的消减能力、对径流洪峰的延缓能力以及蓄排水能力.【结果】假俭草植草沟在消减径流方面最为出色,不同降水条件下地表径流率均未超过10%,百慕大草植草沟消减径流性能次之,大叶油草植草沟最差,且三者差异显著.小雨条件下由百慕大草构成的植草沟砂层渗水率能力最高,为73.197%,大雨时三者无明显差异,暴雨时由假俭草构成的植草沟表现最好,砂层渗水率为79.922%;蓄水效果方面,假俭草植草沟在不同降雨条件下均优于其他2种植草沟.【结论】小雨状态下,百慕大草植草沟的渗排水能力更强;暴雨条件下,假俭草植草沟对于地表径流的消减能力和延缓径流洪峰的能力均为最优.

【Objective】 The effects of different grass species on runoff control and water conservation in grass swales were studied in order to screen suitable grasses for the usage in grass swale grasses under different rainfall intensities,and provide theoretical basis for the construction of sponge city.【Method】 Axonopus compressus,Cynodon dactylon and Eremochloa ophiuroide were used to study the ability to reduce runoff,delay runoff flood peak,water conservation and drainage under 3 simulated rainfall intensities(light rain,heavy rain and rainstorm).【Result】 E.ophiuroide showed the best performance in reducing runoff,and the surface runoff rate under different rainfall intensities was less than 10%.C.dactylon take the second place and followed by A.compressus.The difference between 3 species was significant.The water infiltration of sand layer of grass swale by growing C.dactylon was the highest under light rain(73.197%).There was no significant difference between 3 species under heavy rain.And it was the highest while E.ophiuroide was used under rainstorm(79.922%).In terms of water conservation,E.ophiuroide was the best under 3 rainfall intensities.【Conclusion】 The infiltration and drainage of grass swale with C.dactylon were strong under light rain.Under rainstorm,the ability of E.ophiuroide to reduce the surface runoff and delay runoff peak was the best.