Third Party Engineer’s Report – Phase 3 – Update on Change in Scope & Modeling

As many of you know, LID 19 engaged Aptim to provide recommendations for system improvements or modifications in its Phase 3 report. However, LID 19’s Board recently voted to modify Aptim’s Phase 3 scope to provide recommendations for system improvements or modifications for limited events up to a 100-year rainstorm event. Aptim’s Phase 3 report will also take into consideration recent updates to rainfall data from the National Oceanic and Atmospheric Administration’s (NOAA) Atlas 14 draft report.

The decision to modify Aptim’s Phase 3 Report was made as a result of the Board’s analysis of currently available 1D modeling, which may be insufficient for purposes of modeling extreme rainfall events, such as Hurricane Harvey. In order to obtain a model with improved predictive data to allow LID 19 to better analyze potential regional improvements or modifications for extreme rainfall events, LID 19’s Board voted to begin work to create a new comprehensive 2D hydraulic & hydrologic model for the entire lower Steep Bank Creek watershed, including surrounding areas. This modeling effort is expected to take several months, and updates regarding progress on the modeling project will be provided on the website.