基于新安江改进模型和NAM模型的通县站洪水预报研究

Flood Forecasting Research of Tongxian Based on Improved Xin’anjiang and NAM Model

【目的】以北京市北运河通县站为例,使用新安江改进模型和降雨径流(NAM)模型进行洪水预报。【方法】选取1980—2018年共18场历史洪水进行参数率定和验证,考虑下垫面变化等因素,分为1980—2000年和2001—2018年2个阶段进行模拟。【结果】(1)新安江改进模型1980—2000年的洪峰总体合格率达75%,洪量达50%;2001—2018年间洪峰总体合格率达到67%,洪量达78%,明显优于1980—2001年间的模拟结果;(2)NAM模型1980—2000年间洪峰总体合格率达89%,洪量达40%;2001—2018年间洪峰、洪量总体合格率均为78%;(3)NAM模型对洪峰的模拟效果在2个时段均优于新安江改进模型,但对洪量模拟优势并不明显;NAM模型和新安江改进模型对2001—2018年洪峰和洪量模拟效果相近;(4)新安江改进模型中不透水面积Imp、地表径流调蓄系数Cks、土壤含水总量Wm、壤中流调蓄系数Cki和自由水蓄量Sm对模拟结果较为敏感;NAM模型中地表蓄水层蓄水容量Umax、浅层蓄水层土壤蓄水量Lmax和地表径流调蓄系数CQOF对模拟结果影响较大。【结论】新安江改进模型和NAM模型对通县站洪水预报均有一定适用性,但二者模拟效果差异并不明显。整体上,二者对2000年后的历史洪水模拟效果要优于2000年前,2000年前的洪峰模拟合格率明显高于洪量。建议根据预报流域、资料具体情况,综合选用模型进行模拟。

【Objective】The flood forecasting research was focused on Tongxian which was located on Bei Channel riverside in Beijing.Improved Xin’anjiang and NAM model were used in the process of forecasting.Significant floods in the year of 1980—2018 were chosen to simulate.【Method】There were 18 historical floods.Because of the changing of land surface condition,they were grouped by the periods of 1980—2000 and 2001—2018,respectively.【Result】(1)In the period of 1980—2000,the qualification rate of flood peak and flood total aggregate predicted by Xinanjiang model has reached 75%and 50%generally.Besides,in the stage of 2001—2018,the qualification rate of flood peak and flood total aggregate value were reached at 67%and 78%also predicated by Xin’anjiang model,which was obviously better than the results of 1980—2000.(2)The qualification rate of flood peak and flood total aggregate predicted by NAM model in the stage of 1980—2000 were 89%and 40%,perspectively.In the stage of 2001—2018,the qualification rate of flood peak and flood total aggregate both reached at 78%.(3)NAM Model was more suitable than Xin’anjiang model to simulate flood peak in two different stages,but it was weak in simulating flood total aggregate.In the period of 2001—2018,the two models performed similarly.(4)Parameters of Imp,Cks,Wm,Cki and Sm in Xin’anjiang model were sensitive to the simulating results.In NAM model,parameters of Umax,Lmax and CQOF influenced the simulating results positively.【Conclusion】Both the improved Xin’anjiang and NAM model were generally applicable to the flood forecasting of Tongxian.However,the difference of simulating performance between the two models was not obvious.In general,the simulating performance of the two kinds of models in the period of 2001—2018 was better than the period of 1980—2000.The qualification rate of flood peak in the period of 2001—2018 was obviously higher than the qualification rate of floods total aggregate in the period of 1980—2000.Choosing the simulating model was decided by the detail situation of drainage area and the historical hydrology data.