Development and Application of a QGIS-Based Model to Estimate Monthly Streamflow

Hanyong Lee,Min Suh Chae,Jong-Yoon Park,Kyoung Jae Lim,Youn Shik Park

doi:10.3390/ijgi11010040

Abstract

Changes in rainfall pattern and land use have caused considerable impacts on the hydrological behavior of watersheds; a Long-Term Hydrologic Impact Analysis (L-THIA) model has been used to simulate such variations. The L-THIA model defines curve number according to the land use and hydrological soil group before calculating the direct runoff based on the amount of rainfall, making it a convenient method of analysis. Recently, a method was proposed to estimate baseflow using this model, which may be used to estimate the overall streamflow. Given that this model considers the spatial distribution of land use and hydrological soil groups and must use rainfall data at multiple positions, it requires the usage of a geographical information system (GIS). Therefore, a model that estimates streamflow using land use maps, hydrologic soil group maps, and rain gauge station maps in QGIS, a popular GIS software, was developed. This model was tested in 15 watersheds.

Highlights

QGIS-Based Model to EstimateThe hydrological behavior of a watershed may vary according to changes in rainfall pattern or land use typically caused by urbanization or industrialization [1,2]
The Long-Term Hydrologic Impact Analysis (L-THIA) model was initially developed in a spreadsheet format [4], which was later developed for use in geographic information systems (GISs) [5,6]
This study developed an L-THIA model that estimates seasonal variations in streamflow using a monthly baseflow estimation method [21], which can be applied to the recently proposed L-THIA model using land use maps, hydrological soil group maps, and rainfall data measured from multiple sources

Summary

Introduction

The hydrological behavior of a watershed may vary according to changes in rainfall pattern or land use typically caused by urbanization or industrialization [1,2]. These changes may increase the impermeability in the watershed or alter the frequency or amount of rainfall, which decreases the groundwater recharge; thereby, increasing or changing direct runoff, peak runoff, the potential of downstream flooding, and seasonal variance in hydrological behavior [3]. Rainfall patterns or land use change analyses are performed using hydrological models; the Long-Term Hydrologic Impact Analysis (L-THIA) model has been regularly used since its development in 1994 [4,5,6,7]. Bhaduri et al [5] and Lim et al [7] used the L-THIA/NPS

Methods

Results

Conclusion