In recent years, the Taiwan government has established a number of flood control facilities such as dikes, pumping stations and drainage systems to effectively reduce downstream flooding. However, with continued development and urbanization of catchment areas, the original designs of most flood control facilities have become outdated. Hillside lands in the upper and middle reaches of river basins have undergone urban development through unsound engineering practices, paving the way for heavy downstream flooding. Therefore, proper river basin management should include both upstream and downstream sides. The main purpose of the paper is to simulate non-urban inundation areas with various degrees of development (0%, 10%, 20%, 40% and 60%), over two different return periods of 25 years and 200 years, for intensive rainfall events in the Shi-Chi District, Taiwan. Through hydrological analysis and numerical simulations of inundation, quantitative data on inundation potential have been established based on the land development conditions along the hillsides on the upper and middle reaches of the Keelung River Basin. The simulated results show that the increase in the extent of land development in the upper reaches causes an increase in the area and depth of inundation, resulting in an increased risk of flooding in downstream areas. If the land-use policy makers in the upper reaches of the river basin’s hillsides do not properly manage the land development, the risk of flooding in downstream areas will increase. In such an event, the policy makers should first review the situation to understand the problem with the consideration of this study. Thus, proper development and flood mitigation in hillsides can be established.
References
[1]
Leu, S.S.; Yu, J.K. Study of the impact factors of hillside construction projects[in Chinese]. J. Archit. 2003, 39, 71–86.
[2]
Chang, S.M. Implementation of hillside development regulation policy in Taiwan based on intergovernmental relation[in Chinese]. Public Admin. Policy 2001, 33, 77–100.
[3]
Chen, S.C.; Chan, H.C.; Li, Y.H. Observations on flow and local scour around submerged flexible vegetation. Adv. Water Resour. 2012, 43, 28–37, doi:10.1016/j.advwatres.2012.03.017.
[4]
Hsu, M.H.; Chen, S.H.; Chang, T.J. Inundation simulation for urban drainage basin with storm sewer system. J. Hydrol. 2000, 234, 21–37, doi:10.1016/S0022-1694(00)00237-7.
Chen, A.; Djordjevic, S.; Leandro, J.; Evans, B.; Dragan, S. Simulation of the Building Blockage Effect in Urban Flood Modeling. In Proceedings of11th International Conference on Urban Drainage, Edinburgh, UK, 31 August–5 September 2008.
[7]
Water Resources Agency. Continued assessment and Monitoring for the Effects of Flood Disaster Reduction to the Integrated Flood Control Plan at Keelung River. [in Chinese]; Water Resources Agency of Ministry of Economic Affairs: Taipei, Taiwan, 2007.
[8]
Huber, W.C.; Dickinson, R.E. Storm Water Management Model, User’s Manual Version IV; U.S. Environmental Protection Agency: Washington, DC, USA, 1988.
[9]
Hsu, M.H.; Chen, A.S.; Chen, L.C.; Lee, C.S.; Lin, F.T.; Huang, C.J. A GIS-based decision support system for typhoon emergency response in Taiwan. Geotech. Geol. Eng. 2011, 29, 7–12, doi:10.1007/s10706-010-9362-0.
[10]
Neal, J.C.; Fewtrell, T.J.; Bates, P.D.; Wright, N.G. A comparison of three parallelisation methods for 2D flood inundation models. Environ. Model. Softw. 2010, 25, 398–411, doi:10.1016/j.envsoft.2009.11.007.
[11]
Wang, J.I.; Su, M.D.; Hsu, M.H.; Chang, T.J. Establishment of Systematic Models for Flood Damage Evaluation. [in Chinese]; Water Resources Agency of Ministry of Economic Affairs: Taipei, Taiwan, 2003.
[12]
Liang, Q.; Du, G.; Hall, J.W.; Borthwick, A.G.L. Flood inundation modeling with an adaptive quadtree grid shallow water equation solver. J. Hydraul. Eng. 2008.
[13]
Smith, R.H. Development of Flood Routing Model for Small Meandering Rivers. Ph.D. Thesis, University of Missouri at Rolla, Rolla, MO, USA, 1978.
[14]
Akan, A.O.; Yen, B.C. Diffusive wave flood routing in channel networks. J. Hydraul. Div. 1981, 107, 719–732.
[15]
Yen, B.C.; Akan, A.O. Hydraulic design of urban drainage systems. In Hydraulic Design Handbook; Mays, L.W., Ed.; McGraw Hill Inc.: New York, NY, USA, 1999; pp. 1–14. Chapter 14.
[16]
Yen, B.C.; Tsai, C.W.S. On non-inertia wave versus diffusion wave in flood routing. J. Hydrol. 2001, 44, 97–104.
[17]
Saaty, T.L. A scaling method for proiorities in hierarchical structure. J. Math. Psychol. 1997, 15, 234–281, doi:10.1016/0022-2496(77)90033-5.
[18]
Teng, W.H.; Chen, C.J.; Tang, K.L.; Chen, C.H. Influence on the flood disasters in the river downstream by the degree of hillside development[in Chinese]. J. Archit. 2010, 73, 191–206.
