MODELING FLOOD RUNOFF RESPONSE TO LAND COVER CHANGE WITH RAINFALL SPATIAL DISTRIBUTION IN URBANIZED CATCHMENT

Abstract

This present study is proposed to overcome the lack of distributed data, usually occurs in developing country, in order to simulate fully distributed flood runoff response to land cover change in urbanized catchment. A method to produce spatial distributed hourly rainfall is developed. Linear interpolation approach is used to estimate hourly rainfall by considering hourly rainfall deviation from daily average. Infiltration in urban area is accommodated by applying spatial distributed urban density. The urban density is detected using the land cover and district area data. This parameter is further adjusted to get the value of infiltration coefficient in urban area which determines the loss of water in urban area. The model, a combination of 2D runoff model with NCF tank model, is applied to the upper part of Ciliwung River basin in Indonesia. By using spatial distributed parameters, model performance has improved. It is also shown that land cover changes due to urbanization, in response, have intensified flood runoff discharge.