Realizing Zero Delta Q Due to the Change of Land-Use Using Horizontal Recharge Pipe

Abstract

Though recharge buildings such as recharge wells and bio pores have widely been implemented in the field, their design to reduce flood runoff is not as expected. This study aims to formulate recharge using the porous horizontal recharge pipelines (HRP) as a basis to calculate the needs of HRP purposely to achieve zero ΔQ due to the changes in land use. The experimental method uses PVC pipe 20cm in diameter, 2m; 4m; 6m; and 8m in length, with the middle part connected with a 100 cm high vertical pipe. The horizontal pipe was perforated with a pipe wall porosity of 0.006; 0.012; 0.018; 0.024; and 0.048 and wrapped in geotextile. The observation of the infiltration recharge -was conducted by filling the water and observing the decrease in the water level using the sensor and recording. The decline in water level was converted into infiltration recharge -for each high water pressure. The research was conducted in a horizontal pipe with holes below the groundwater surface on clay soil with a 6.89x10-7 cm/sec permeability. It was then found the correlation between infiltration recharge -and pipe wall porosity, pipe length, and water pressure height were obtained in the form of a regression equation of Q=0.0972*P0.025*L0.193*H2,179 with a correlation coefficient of 0.9136. The HRP implementation to meet zero ΔQ due to the changes in land use using the rational method has been produced in graphical form, while the hydrograph method was presented in the case form. In the Silandak watershed, with an area of 10.30 km2, there was an increase in the coefficient of drainage from 0.39 in 2002 to 0.58 in 2019. To achieve zero ΔQ of flood hydrograph of a 50-year return period, 4200 HRP units are needed. Thus, HRP can overcome flooding due to changes in land use. However, this research must still be developed by adding pipe diameter and soil permeability variables.