黄土丘陵沟壑区沟道土地整治工程对流域产汇流的影响

Influence of Land Consolidation Engineering of Gully Channel on Watershed Runoff Yield and Concentration in Loess Hilly and Gully Region

针对黄土高原丘陵沟壑区沟道整治工程造成的下垫面的剧烈变化,通过野外调查、室内试验模拟的方法,研究了流域沟道不同整治比例(0%、20%、30%、40%、50%)、不同降雨强度(40、60、80、100、120mm/h)情况下,沟道地表径流流速变化、流域控制工程坝前蓄水变化及对沟道洪水标准的影响。结果表明,随着沟道整治比例的增大,相对于沟道无整治工程时地表径流平均流速分别减小6.21%、10.95%、19.85%、21.78%,流域控制工程坝前平均蓄水分别减小3.94%、15.55%、17.23%、23.90%,径流系数由无整治工程时的0.80减小至0.61。随着降雨强度的增大,平均流速由0.102m/s增大至0.160m/s,流域控制工程坝前平均蓄水与40mm/h时相比分别增加5.90%、24.17%、30.80%、38.82%,径流系数由0.59扩大至0.81。由此可见,流域沟道不同整治比例和不同降雨强度对流域控制工程的径流蓄积、径流系数及洪水设计均具有较大影响,实际工程设计中应考虑其影响,不可忽略。

Land consolidation engineering of gully channel in the loess hilly and gully region has brought dramatic changes of land surface.The impact of different land consolidation proportions and rainfall intensities on channel surface runoff velocity,the impoundment volume in front of dams and the flood standard of gully channel were studied by field investigations and lab simulations.The results show that with the increasing of land consolidation proportion,the average velocity of surface runoff decreased by 6.21%,10.95%,19.85% and 21.78%,respectively.The average impoundment volume in front of dams decreased by 3.94%,15.55%,17.23% and 23.90%,respectively,and the runoff coefficient decreased from 0.80 to 0.61.With the increasing of the rainfall intensity,the average velocity increased from 0.102m/s to 0.160m/s.Compared to the lowest rainfall intensity,the average impoundment volume in front of dams increased by5.90%,24.17%,30.80% and 38.82%,respectively,and the runoff coefficient increased from 0.59 to 0.81.Therefore,different consolidation proportions and different rainfall intensities have a great impact on runoff accumulation,runoff coefficient and designed flood standard and that should not be neglected in the real projects.