Estimation of Peak Flood Discharge for an Ungauged River: A Case Study of the Kunur River, West Bengal

Abstract

Due to unavailability of sufficient discharge data for many rivers, hydrologists have used indirect methods for deriving flood discharge amount, that is, application of channel geometry and hydrological models, for the estimation of peak discharge in the selected ungauged river basin(s) in their research/project works. This paper has studied the estimation of peak flood discharge of the Kunur River Basin, a major tributary of the Ajay River in the lower Gangetic plain. To achieve this objective, field measurements, GIS technique, and several channel geometry equations are adopted. Three important geomorphic based hydrological modelsmanning's equation, kinematic wave parameter (KWP), and SCS curve number (CN) method-have been used for computing peak discharge during the flood season, based on daily rainfall data of September, 2000. Peak discharges, calculated by different given models, are 239.44 m 3 /s, 204.08 m 3 /s, and 146.52 m 3 /s, respectively. The hydrograph has demonstrated the sudden increase with heavy rainfall from the 18th to the 22nd of September, 2000. As a result, a havoc flood condition was generated in the confluence zone of Ajay and Kunur Rivers. This hydrograph might be not only successful application for flood forecasting but also for management of the lower Ajay River Basin as well as the downstream area of Kunur Basin.

Relative Effect of Location Alternatives on Urban Hydrology. The Case of Greater Port-Harcourt Watershed, Niger Delta

“…Compared to other studies, the MAE for peak discharge was 39.8 m 3 /s and was reasonable when compared to the MAE value observed [72]. Similarly, RMSE estimated as 45.48 m 3 /s suggests a reasonable performance when compared to RMSE values recorded in Roy and Mistri [68]. Given the limited data and the performance of the model, model prediction was deemed reliable for modelling other historical and future hydrologic changes.…”

“…This is a reliable alternative for determining parameters X and K and for simulating open channel discharge downstream in ungagged river channels. K equals the flood wave time travel through the reach and X equals the dimensionless weight (0 ≤ X ≤ 0.5) [68].…”

“…Calibration of the model for this study was challenging due to the unavailability of observed discharge data and this is a typical problem for hydrology research in most developing regions. To overcome this problem, an alternative method-prediction in the ungagged basin (PUB) approach was adopted as described by Roy [68] and Ford [66]. In this method, the model parameters for loss, transform and channel routing were mainly derived from the digital elevation model (DEM), soil and satellite land cover maps.…”

Analysis of a Flash Flood in a Small Basin in Crete

“…where A is the area of the basin equal to 23.17 km 2 , L is the length of the main thalweg equal to 11.705 km and ∆H is the difference in mean elevation from outlet's elevation equal to 197.17 m, as derived from the ArcGIS design. Another empirical formula widely used for calculating T c (h) is the one of Kirpich, which was developed for rural watersheds in Tennessee ranging from 0.004 km 2 to 0.453 km 2 and having slopes from 3% to 10% [41], as follows:…”

Modeling of the Precipitation Induced Flash Flood in Sarpang, Bhutan Using Hec-Ras

“…Average daily rainfall data (1996-2016) of Sarpang rain gauge station were collected from DHMS, Bhutan and peak discharge was calculated by Kinematic Wave Parameter (KWP) for Flow Velocity and Discharge Estimation method (Rodriguez-Iturbe et al 1982) shown in equation (1) 11 . Average slope of channel as 0.4 and channel outlet cross section of 600 m 2 were calculated from stream profile and stream cross section respectively which were generated in HEC-RAS software.…”