MANAGEMENT&ECONOMICS

Assessment of streamflow variation considering long-term land-use change in a watershed

Joonwoo Noh1   Yeonsu Kim1   Wansik Yu1   Jisoo Yu2,*   

1Integrated Water Resources Management Research Center, K-water Research Institute, Daejeon 34045, Korea
2River Basin Management Department, Yeongsangang&Seomjingang Rivers Basin Head Office, K-water, Gwangju 61949, Korea

Abstract

Land-use change has an important role in the hydrologic characteristics of watersheds because it alters various hydrologic components such as interception, infiltration, and evapotranspiration. For example, rapid urbanization in a watershed reduces infiltration rates and increases peak flow which lead to changes in the hydrologic responses. In this study, a physical hydrologic model the soil and water assessment tool (SWAT) was used to assess long-term continuous daily streamflow corresponding to land-use changes that occurred in the Naesungchun river watershed. For a 30-year model simulation, 3 different land-use maps of the 1990s, 2000s, and 2010s were used to identify the impacts of the land-use changes. Using SWAT-CUP (calibration and uncertainty program), an automated parameter calibration tool, 23 parameters were selected, optimized and compared with the daily streamflow data observed at the upstream, midstream and downstream locations of the watershed. The statistical indexes used for the model calibration and validation show that the model performance is improved at the downstream location of the Naesungchun river. The simulated streamflow in the mainstream considering land-use change increases up to -2 - 30 cm compared with the results simulated with the single land-use map. However, the difference was not significant in the tributaries with or without the impact of land-use change.

Figures & Tables

Fig. 1. Land use update (LUP) tool (saraswat-swat.rcac.purdue.edu). HRU, hydrologic response units; SWAT, soil and water assessment tool; LULC, land use and land cover; ID, identification; LUC, land use change.