Storm System Models

Project Overview

The City of San Marcos has identified the need to evaluate some of its existing flooding problem areas with the use of two-dimensional (2D) hydraulic modeling.  The utilization of 2D modeling allows for the dynamic analysis of a system considering drainage installations (ditches, storm sewers, curbs and inlets, etc.), streets and topography.  2D model results will help identify proposed drainage facility requirements.

The first area evaluated with 2D modeling was within the Purgatory Creek Watershed. The project included the initial setup of a detailed InfoWorks ICM model for approximately two square miles of the Purgatory Creek Watershed and an assessment of existing flood conditions in this area. The primary intent of the drainage study was to identify areas that do not currently meet the City’s design storm criteria which requires that all drainage facilities (including street curbs, gutters, inlets and storm drains) be designed to intercept and transport runoff from a 25-year frequency storm.  Results will be used to identify future capital improvement projects to correct the identified drainage issue.

The City is in the process of identifying additional areas to be evaluated using 2D modeling.

 Purgatory Creek Watershed Phase 1 Drainage Study (PDF)