Georeference, rainfall-runoff modeling and 3D dynamic simulation

Abstract

Current 2D-GIS based rainfall-runoff modeling provides very little evidence regarding the influence of georeference and its transformation while modeling flow direction and runoff volume. Within GIS, all stream networks, surface structures and its properties must be assigned and preserved within appropriate projection plane characteristics. In addition, the inability of GIS to realistically explore the momentum and continuity aspects of overland flow and runoff process has been proven to be the shortcomings of the system. Inclusion of volumetric soft geoobjects (VSG) would offer substantial effort towards representing 3D dynamic stormwater flow that hits the flood-plain areas, estimating infiltrated and saturated stormwater to reduce flash flood and preventing landslide disaster realistically. This study aims to visualize the influence of georeference towards determining areas prone to runoff and its volume using 3D VSG data model for empirical based Soil Conservation Service -Curve Number (SCS-CN) method. Runoff and overland flow generated from these methods are analyzed by focusing on spatial object preservation techniques of currently implementing conformal based Malaysian Rectified Skew Orthomorphic (MRSO) and equidistant based Cassini-Soldner projection. Land use of Industrial, Infrastructure and Grass / Pasture distributes high differential computation of surface runoff volume with 10.86 percent, 16.98 percent and 13.48 percent respectively due to different projection plane.

Hydrological Modeling in Malaysia

“…References [53][54][55][56][57] used the commercial software InfoWorks River Simulation (IWRS), while [58] used InfoWorks Collection System (IWCS) from the UK to simulate rainfall runoff. Hydrological model from USA such as HEC [59][60][61], L-THIA program [62], MIKE [63][64][65], and MAYA 3D have been used to simulate flood events [66]. The 2DSWAMP and XP-SWMM models from Australia are used by [67] and [68] to simulate runoff.…”

“…They were successful in producing a Flood Hazard Mapping for Urban Area (FHMUA). A free commercial program, L-THIA (developed by Purdue University), simulated the runoff at Pinang River, Pulau Pinang [62]. Reference [65] analyzed the flood event at Damansara River, Selangor using MIKE-FLOOD.…”