1. The Influence of Urban Development Density on Water Pollution Kyushik Oh and Dong woo Lee Department of Urban Planning Hanyang University, Korea

2. Introduction ◈ Occurrence of many kinds of Environmental problems by urban developments ◈ Need for comprehensive water quality management approach such as Total Maximum Daily Load Program (TMDL) ◈ Need for Cumulative impacts for SEA (Strategic Environmental Assessment)

3. Analyzing the pattern of cumulative impacts on water pollution caused by urban developments Using in the decision making of urban planning Assistance in the enforcement of SEA of EIA Objective

4. Concept of cumulative impacts ◈ Result of interactions between incremental developments projects in space and time periods Exceeding an environmental carrying capacity Occurrence of serious environmental problems

5. YongIn BunDang The study area and methods ◈ Study area ■ The upper reaches of the Tancheon watershed area

6. ◈ Remote sensed data on study area Before development (1985) After development (2003)

7. Comparison of the increase of BOD intensity with the increase of urban developments Identification of patterns of water pollution Analysis of rainfall data Rainfall data Pollution intensity for seasons Water quality data ◈ M ethods Urban developments increase Urban Developments Factor Urban area Population Employee …

8. ◈ Sub-basins and water quality observation points Legend

9. Result The diffusion of a sewerage Urban area Population Employees

10. ◈ Results of hierarchical cluster analysis on rainfall ■ Dry season: January-May, October-December ■ Wet season: June-September ◈ Changes of BOD intensity Dry seasonWet season

11. Patterns of water pollution WQOP1WQOP2 Urban area Popu- lation

12. WQOP1WQOP2 Employee Water pollution is getting more serious by urban developments

13. Variable linearlogicExponential FunctionR2R2 R2R2 R2R2 Variation of urban area WQOP1 y = 3.606x - 15.186 0.704 y = 22.09Ln(x) - 31.434 0.5537 y = 1.4681e 0.2576 x Exponenti al R2 = 0.8381 WQOP2 y = 1.2839x - 3.6406 0.6927 y = 11.121Ln(x) - 14.589 0.5476 y = 2.6509e 0.1096 x 0.8254 Variation of population WQOP1 y = 0.2102x - 4.7031 0.9223 y = 16.608Ln(x) - 58.873 0.8115 y = 3.2312e 0.0146 x 0.9711 WQOP2 y = 0.1206x + 0.4958 0.9247 y = 8.071Ln(x) - 22.762 0.7084 y = 3.9593e 0.0098 x 0.9387 Variation of business WQOP1 y = 0.0125x - 19.055 0.8228 y = 31.427Ln(x) - 232.81 0.7682 y = 1.205e 0.0009x 0.9105 WQOP2 y = 0.0075x - 12.585 0.9421 y = 26.128Ln(x) - 198.77 0.9178 y = 1.7951e 0.0005 x 0.9487 ◈ Patterns of water pollution

14. Conclusions ◈ Results ■ Observing cumulative impacts occurred as a result of urban developments ■ Demonstrating the need for considering cumulative impacts for an effective water quality management ◈ Limitations ■ Insufficient water quality observation data ■ Considering urban developments as only sources of cumulative impacts

15. Cumulative Impacts of Urban Developments on Water Pollution Kyushik Oh and Dong woo Lee Department of Urban Planning Hanyang University, Korea