Drought Risk Assessment of Irrigation Project Areas in a River Basin

A model is developed for drought risk estimation in a river basin with an irrigation project. Drought risk is expressed as a product of drought hazard, exposure and vulnerability. Drought hazard is a function of rainfall, groundwater potential, groundwater quality and water storage in reservoirs. Exposure is the presence of irrigation system and crop areas inside or outside the irrigation project. Vulnerability or the lack of resistance damages due to drought depends on types of irrigation system, types of crop and their economic values. Vulnerability and exposure can be combined as consequences. The product of normalized hazard and consequences is called risk. The model is applied to assess drought risk in drought year of 2015 in the Munbon-Lamsae River Basin in Northeast Thailand. Monthly data in the past 30 years are collected. This includes rainfall, stream flow, groundwater potential and groundwater quality; and available water storage in reservoirs. Maps of hazard, consequences and risk conditions of the study area are computed in drought months such as in June 2015. The maps are calibrated for consistency with the actual field conditions by adjusting the weighting factors or coefficients of the model parameters. The developed model is further applied to estimate change in drought risk due change of irrigation system, for example when the types of irrigation system is changed from surface irrigation system to sprinkler irrigation system. The drought risk in the study area is significantly reduced because the sprinkler system can supply irrigation water more efficiently with less water loss

A framework of integrated hydrological and hydrodynamic models using synthetic rainfall for flash flood hazard mapping of ungauged catchments in tropical zones

Flash flood hazard maps provide a scientific support to mitigate flash flood risk. The present study develops a practical framework with the help of integrated hydrological and hydrodynamic modelling in order to estimate the potential flash floods. We selected a small pilot catchment which has already suffered from flash floods in the past. This catchment is located in the Nan River basin, northern Thailand. Reliable meteorological and hydrometric data are missing in the catchment. Consequently, the entire upper basin of the main river was modelled with the help of the hydrological modelling system PANTA RHEI. In this basin, three monitoring stations are located along the main river. PANTA RHEI was calibrated and validated with the extreme flood events in June 2011 and July 2008, respectively. The results show a good agreement with the observed discharge data. In order to create potential flash flood scenarios, synthetic rainfall series were derived from temporal rainfall patterns based on the radar-rainfall observation and different rainfall depths from regional rainfall frequency analysis. The temporal rainfall patterns were characterized by catchment-averaged rainfall series selected from 13 rainstorms in 2008 and 2011 within the region. For regional rainfall frequency analysis, the well-known L-moments approach and related criteria were used to examine extremely climatic homogeneity of the region. According to the L-moments approach, Generalized Pareto distribution was recognized as the regional frequency distribution. The synthetic rainfall series were fed into the PANTA RHEI model. The simulated results from PANTA RHEI were provided to a 2-D hydrodynamic model (MEADFLOW), and various simulations were performed. Results from the integrated modelling framework are used in the ongoing study to regionalize and map the spatial distribution of flash flood hazards with four levels of flood severities. As an overall outcome, the presented framework can be applied in areas with inadequate runoff records

Inflow Prediction for the Upstream Boundary Condition of the Chao Phraya River Model Using an Artificial Neural Network

Source: ICHE Conference Archive - https://mdi-de.baw.de/icheArchiv

Tide Prediction for the Downstream Boundary Condition of the Chao-Phraya River Integrated River Model Using Harmonic Analysis

Source: ICHE Conference Archive - https://mdi-de.baw.de/icheArchiv

Comprehensive Assessment of Flood Hazard, Vulnerability, and Flood Risk at the Household Level in a Municipality Area: A Case Study of Nan Province, Thailand

Estimating flood hazard, vulnerability, and flood risk at the household level in the past did not fully consider all relevant parameters. The main objective of this study is to improve this drawback by developing a new comprehensive and systematic methodology considering all relevant parameters and their weighting factors. This new methodology is applied to a case study of flood inundation in a municipal area of Nan City in the Upper Nan River Basin in Thailand. Field and questionnaire surveys were carried out to collect pertinent data for input into the new methodology for estimating flood hazard, vulnerability, and risk. Designed floods for various return periods were predicted using flood simulation models for assessing flood risk. The flood risk maps constructed for the return periods of 10–500 years show a substantial increase in flood risk with the return periods. The results are consistent with past flood damages, which were significant near and along the riverbanks where ground elevation is low, population density is high, and the number of household properties are high. In conclusion, this new comprehensive methodology yielded realistic results and can be used further to assess the effectiveness of various proposed flood mitigation measures

Comprehensive Assessment of Flood Hazard, Vulnerability, and Flood Risk at the Household Level in a Municipality Area: A Case Study of Nan Province, Thailand

Estimating flood hazard, vulnerability, and flood risk at the household level in the past did not fully consider all relevant parameters. The main objective of this study is to improve this drawback by developing a new comprehensive and systematic methodology considering all relevant parameters and their weighting factors. This new methodology is applied to a case study of flood inundation in a municipal area of Nan City in the Upper Nan River Basin in Thailand. Field and questionnaire surveys were carried out to collect pertinent data for input into the new methodology for estimating flood hazard, vulnerability, and risk. Designed floods for various return periods were predicted using flood simulation models for assessing flood risk. The flood risk maps constructed for the return periods of 10–500 years show a substantial increase in flood risk with the return periods. The results are consistent with past flood damages, which were significant near and along the riverbanks where ground elevation is low, population density is high, and the number of household properties are high. In conclusion, this new comprehensive methodology yielded realistic results and can be used further to assess the effectiveness of various proposed flood mitigation measures