KOREA INSTITUTE OF GEOSCIENCE AND MINERAL RESOURCES
THE WORLD'S LEADING RESEARCH
INSTITUTE OF GEOSCIENCE
EFFECTS OF URBAN DEVELOPMENT ON HYDROGEOLOGICAL ENVIRONMENT
Land use changes of the Banseok stream catchment are analyzed quantitatively to estimate the urbanization effects on excess rainfall and runoff. After massive development in the Banseok stream catchment from the 1980s, a total area of impermeable layers such as building roofs and road pavements increased by approximately 6 km2, while the same area of forest and agricultural lands decreased. The total agricultural area bounced again after 2000 due to deforestation for farming. Decrease in forest area and increase in impermeable layers may consequence fast and intense hydrologic response by the precipitation. Using the rainfall-runoff model, hydrographs of the Banseok stream at each stage of development were estimated. The peak from the 1980 graph becomes higher and the slope steeper after the rapid development in 1990. The excess rainfall flows to outlets more rapidly and more intensely than that in the pre-development stage, implying that downstream regions in the developed area have become more susceptible to flooding.
Rapidly moving landslides are extremely hazardous phenomena capable of causing severe damage to ecosystems in the Republic of Korea. Effective and sustainable landslide risk reduction measures have been realized with the development of a reliable early-warning model. The KIGAM landslide monitoring system is operated at eleven different locations in national park areas in Korea. Each monitoring site has an identical landslide detection system, and these work by acquiring local rainfall information and in-situ geotechnical and hydrological
Fig. 1. Land use maps of the Banseok catchment area from 1980 to 2013 (left) and overall areal changes of land use by category (right).
Fig. 2. Modeled unit hydrographs of the Banseok stream in 1980 (blue), 1990 (orange), and 2000 (red).