Disaster Preparedness

Natural disasters such as those caused by Tropical Storm Allison and Hurricanes Andrew and Hugo take many businesses and communities by surprise with the insurmountable damage caused.  Although floods and hurricanes cannot be controlled, Dodson & Associates, Inc. can use the technology and knowledge available to assess businesses and communities for possible risk in order to prepare for and recover after a natural disaster.

Hurricane Preparedness Study

Harris County Public Infrastructure Department

Dodson & Associates, Inc. was authorized to prepare a two-phase study to address Harris County’s hurricane preparedness.  Phase I, which has been completed, was to evaluate the hazards and the damages Harris County would face during a major hurricane and to identify the need for developing a more comprehensive hurricane basic plan.  The results of Phase I indicated that Harris County is extremely vulnerable to a Category 4 or 5 hurricane because the current hurricane basic plan administered by the Harris County Office of Emergency Management (HCOEM) is only adequate to handle Category 1 and 2 hurricanes.  The Phase I study also estimated that the damages for the county would be a least $18-36 billion, which primarily comprises direct losses due to storm surge, rainfall flooding, and wind damage.

Phase II is currently underway.  As a part of this effort, the team is:

1.      Identifying the magnitude of the disaster in terms of the area likely to be flooded and destroyed by rainfall runoff, wind, and storm surge.

2.      Specifically identifying the number of structures affected and economic impacts to the community.

3.      Formulating mitigation measures and expanding the emergency management plan.

The results of the Phase II effort will conclude with a report and a multi-media product that will be geared toward increasing public awareness and support for this effort.

ALERT System Reference Guide

Harris County, Texas

Dodson & Associates, Inc. worked closely with the Harris County Flood Control District (HCFCD) to carefully analyze historical rainfall data and prepare a reference guide used by engineers in advising emergency management officials.  The reference guide is intended to support the Harris County ALERT (Automated Local Evaluation in Real Time) System.  The Harris County ALERT System is a network of precipitation and stream gages that electronically transmit data to a central location for processing of real time flood events.  There are approximately 80 gage sites located throughout Harris County and many of them have been continually monitored since approximately 1983.  

The guide summarizes and illustrates key hydrologic characteristics of previous storm events (such as threshold levels and durations of rainfall which would induce flooding) that can be used to identify flood crests in real time.  With this reference tool engineers can interpret the precipitation and stream stage information for each major drainage channel as the storm occurs.  This analysis represents an extensive effort which involves processing over 10 years of digital data files from about 80 rainfall gages across Harris County. About 2,000 occurrences of flooding or "near flooding" have been identified and analyzed separately, including an analysis of the relationship between the time of rainfall and the time of flooding at various locations. The study involves all major Harris County watersheds.  The immense information in the rainfall and streamflow database is being distilled to a few heuristic relationships between rainfall and the resulting flooding in Harris County.