Introduction

GeoSWMM 2D allows the user to model 2D surface flow by extending the application of the US EPA SWMM 5 engine. It helps to analysis the 1D and 2D domain simultaneously.  It also provides the ability to analyze, visualize, derive and export meaningful results of 2D flood including flood maps.

Widespread overland flooding analysis could be challenges due to strictly 1D solution because the overland flow routes may not be well defined in open spaces and may change depending on the flood occurrence. An integrated 1D-2D solution might be preferred in certain circumstances. The overall concept of the 2D SWMM modeling is to extend the 1D calculation methods in 2D direction that’s why mesh generation is compulsory for 2D modeling. With the generation of 2D mesh alongside of 1D model, nodes are generated which are considered as 2D nodes and those nodes are connected with link layers (2D conduits).

In this SWMM5 2D mesh approach, the typical formulation of the 1D depth-averaged momentum and continuity equations (St-Venant equations) for homogeneous fluids is solved along each component of a computational cell, over a network of junctions and open conduits that represents the problem hydrography, bathymetry or topography. SWMM5 2D does not consider Coriolis force (which may be a factor for very large study areas), wind shear forces or turbulent eddy viscosity. SWMM5 2D assumes flow between adjacent computational cells are predominantly 1 dimensional, and that the wave length is significantly greater than the water depth (i.e. the shallow water equations apply).  Thus GeoSWMM 2D representation is a quasi-two dimensional approach.