Development of Stormwater Drainage Network Model: MODRAIN Code

Abstract

The development of a storm drainage design and simulation model called MODRAIN is presented. The MODRAIN code is written in visual basic language, version 6.0 (VBL) as well as Fortran IV. It consists of two parts; the MAIN program and a subroutine, SDRAIN. In the MAIN program all the input data are entered on screen for VBL. The MAIN program simulates the catchment runoff while the subroutine, SDRAIN sizes the drain by computing depth and width values of each channel cross-section from simulated runoffs. The program was then validated against the prototype network cited in literature. The error range for the manually computed (textbook solution) and simulated depth and width values of drains as per cross sectional areas is between 0.0 and 18.4%. The modrain program was further applied to the design and assessment of existing drainage network of University of Port Harcourt Permanent site (Unipark) and thus, proved to be a reliable engineering design tool.