Flood-reduction scenario based on land use in Kedurus river basin using SWAT hydrology model

Abstract

The rapid growth population phenomenon has causes excessive land demand for residential and economic activity. Moreover, the rapid urbanization also increases the contribution of land constrains. Land conversion from conservation to cultivation uses affects the surface runoff volume that leads to flooding. According to these problems, it is necessary to take steps to control flood in Kedurus Watershed. One of the proper urban development concept is the Water Sensitive City (WSC). The protection against flood in WSC can be accomplished with the land use arrangement that can reduces the surface runoff. The aim of this research is to determine the proper land use scenario to reduce floods in Kedurus Watershed. In order to reach this aim, the writer uses sensitivity analysis to identify the proper land use scenario to be applied in the watershed and SWAT to select the best scenario. The efforts to reduce flood through the land use scenario (scenario 2) could reduce the flood volume by 44,320.32 m3 or 8.11% of the total volume of flood in the area. The average reduction of flood volume in each sub basins is 12,92% and the highest number of reduction is 65,67% (sub basin 22).

Influence of land use enclave distribution on discharge in a small catchment

“…When the community is not protected by good quality flood protection, the increase in peak discharges over the current terrain configuration when modelling an extreme water year was only an average increase of 165.62% over normal. Similar management functionality in urbanised areas is also described by Purwitaningsiha et al (2020), who describe a decrease in peak discharges of tens of per cent from regular for large catchments.…”

“…A comparison of the simulation of a typical summer rainfall-runoff episode under the model solution with and without the inclusion of the polder in the year used in the actual land use scenario for the above-normal rainfall year (Scenario C0) and the simulation already after the implementation of the polder in 2017 is presented in Figure 5). These results show that, similarly to the assessment of Purwitaningsiha (2020), the SWAT model is highly suitable for simulating possible alternative flood protection solutions in the flood protection planning process. 1).…”