Final San Jacinto River Basin Master Drainage Study Released Today, Recommendations Revealed

This afternoon, Harris County Flood Control District (HCFCD), San Jacinto River Authority (SJRA), Montgomery County, and City of Houston released final results of the massive San Jacinto River Master Drainage Plan (SJMDP) study which began in April 2019.

It will take weeks to digest all this information. It consists of:

That’s more than 3,600 pages, EXCLUDING the zipped materials.

Executive Summary Summarized

The executive summary includes a heat map of historically flooded areas, estimated structural damage costs in the next 50 years, and projected population growth during the same period. Not surprisingly, the three fasted growing areas (West Fork, Spring Creek and Cypress Creek) also show the most projected damage.

The summary then proceeds to flood-damage-reduction strategies. They include:

  • Detention Basins
  • Channel Improvements
  • Floodplain Preservation
  • Buyouts
  • Flood Warning Improvements
  • Floodplain Re-mapping
  • Policy updates
  • Formation of a vision group
  • Flood Response Improvements (Evacuation planning, protection of critical facilities such as hospitals, etc.)

The exec summary also lists the top sixteen project priorities, estimates their costs, outlines possible sources of funding, and lays out next steps.

Project Location Map
Project rankings. Note: Rankings do not necessarily coincide with numbers on map above.

“Benching” in reference to the Kingwood Area involves lowering the floodplain near the West Fork to increase flood capacity. This link shows how a similar project in California worked.

The proposed projects will provide tangible benefits, including reduction in the number of at-risk structures for a range of storms as shown in Figure 1.10 below.

With these projects in place, the level of a 100-year flood at I-69 and the West Fork could be reduced by 5.94 feet, Likewise, where Caney Creek meets the East Fork, the 100-year flood would be reduced by 2.82 feet.

Next Steps

That’s good news indeed for everyone who lives in the San Jacinto Watershed. With this information now in hand, we now can quantify the benefits of projects, priorities them, and get on with the hard work of actual mitigation.

More news to follow.

Posted by Bob Rehak on 12/30/2020

1219 Days since Hurricane Harvey