GIS and Hydrologic/Hydraulic Modeling for Integrated Floodplain/Stormwater Management


March 23 at 12:00 PM

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Presented by: Paul DeBarry, Director of Geospatial Services & Watershed Management,  NTM Engineering, Inc.

Webinar Description: Drainage/flooding problems in the area of the Borough of Carlisle, Cumberland County, Pennsylvania disrupted traffic and caused significant economic damage.   In addition to the flooding issue, water quality for NPDES compliance was a secondary concern.  Skelly-Loy and their sub-consultant NTM Engineering, Inc. (NTM) were contracted by PennDOT to hydrologically and hydraulically model the Borough storm sewer system and determine the cause of problems and proposed solutions.  The process involved data collection of problem areas, use of LiDAR data, survey of the storm sewers, GIS analysis, and hydrologic and hydraulic modeling of the watersheds and storm sewers.  The procedures established are customizable to any municipality that wants to create a solution for flooding, stormwater, and water quality problems.

To evaluate the complex situation, data was imported into GIS and both the Watershed Modeling System (WMS) and the EPA stormwater management model (SWMM) model to generate flows and compute storm sewer backwater conditions.    This aided in the analysis of whether flooding was caused by excess runoff, inadequate inlet capacity, inadequate storm sewer capacity, or backwater from the Letort Spring Run and/or the storm sewers themselves.  This also allowed for siting and analysis of potential low impact development scenarios and stormwater management facilities’ impact to reducing flood flows.

To register, please contact Linda Duffy