Open AccessA time-varying distributed unit hydrograph and its application in flood simulation of small mountainous watersheds
Author(s) -
Yali Wang,
Guodong Mei,
Wei Sha
Publication year - 2021
Publication title -
iop conference series. earth and environmental science
Language(s) - English
Resource type - Journals
eISSN - 1755-1307
pISSN - 1755-1315
DOI - 10.1088/1755-1315/638/1/012068
Subject(s) - hydrograph , flood myth , flash flood , environmental science , hydrology (agriculture) , flood forecasting , flow routing , hec hms , watershed , geology , computer science , geography , geotechnical engineering , archaeology , machine learning
Flood forecasting is an important non-engineering measure to reduce flood damage. Small mountainous watersheds are characterized by rapid flow concentration and steeply rising and falling floods. Their flow concentration process exhibits strong time dependence, which is not well-captured by conventional unit hydrographs. In this paper, four mountainous watersheds were studied, and an algorithm for generating a time-varying distributed unit hydrograph (TVDUH) was proposed. The algorithm was integrated with the China Flash Flood Hydrological Model (CNFF-HM) to simulate small watersheds in the study area. The results showed relatively large Nash-Sutcliffe efficiency (NSE) of about 0.8 for the watersheds during the calibration and validation periods. Then the TVDUH was compared with the time-invariant one. The results showed that the TVDUH could better reflected the flow concentration characteristics of small mountainous watersheds, as the method took into account the effect of rainfall intensity on flow concentration during the computation process. And the TVDUH has great application potential in flood forecasting in mountainous watersheds to reduce the loss of flood disasters.