Increasing of Drainage Channel Capacity by Using Under-drain Box Storage Model

Abstract

The development activity will have an impact on the decrease of water absorption space. If there is happened rainfall, the volume of run-off increases; thus, the right drainage system is needed to fulfill the inundation problem due to the rainfall. The drainage system in the area of Brawijaya University is still using the conventional system, so if there is happened a rainfall, the inundation problem will appear. This research aims to develop the existing drainage system by using the echo-drainage that is Under-drain Box Storage Model. The under-drain box storage is a drainage system with the bottom holes that are serial set along the channel to fill the long storage under the drainage channel directly related to soil. The application of under-drain box storage is through the hydraulic physical model test in the Laboratory of River Engineering, University Brawijaya. The construction of under-drain box storage consists of a rainfall drainage channel, vertical drain hole, and box storage. Based on the research, it is produced the bottom-rack design as follows: the channel bed slope (So) ≤ 0.001, so the Fr number is determined from 0.3 until 0.7, if the channel bed-slope (So) > 0.001, so the Fr number > 0.7. By applying the Under-drain Box Storage in the existing drainage channel in the area of Brawijaya University with a two-year return period, the result shows that the construction can reduce 73.73% of inundation; with five-year return period it can reduce 61.07% of inundation, and with ten-year return period it can reduce 58.07% of inundation.

Keywords: under-drain box storage, run-off reduction, drainage channel capacity.