Tag Archive for: Harris County Flood Control

Surprise in Final Harvey Report

Yesterday, I published on this website the 32-page Final Hurricane Harvey Flood Report from Harris County Flood Control. Today someone asked me, “What was the biggest surprise in it?”  Talk about pressure! Harris County packed lots of meat into those 32 pages! I pondered the question all morning and connected the following dots.

Five Times the Average Flow of Niagra Falls

For me, the biggest surprises were the volume of water going over the Lake Houston Dam and where it came from. At the peak of the storm, the amount of water going over the dam exceeded the volume ofNiagra Falls on an average day by 5X. The final figures actually show more water than previously thought going over the spillway: 491,800 cubic feet per second (cfs) vs. 450,000 cfs previously estimated, an increase of almost 10 percent.

More Flow From East Fork than West

When you look at where all that water came from, there was another surprise. More came from the East Fork than the West! See page 12.

In the East Fork numbers, include Peach Creek, Caney Creek and Luce Bayou; In the West Fork numbers, include Spring Creek and Cypress Creek.

One Third of West Fork Flow Came From Lake Conroe Dam Release

Roughly 240,000 cfs came down the West Fork. Seventy-nine thousand cfs came from the release at the Lake Conroe Dam, according to SJRA estimates. So ONE THIRD of the water coming down the West Fork at its peak was from the release. That’s important for the following reason.

Previously, SJRA indicated the Conroe release was approximately 15 percent of all the water going into Lake Houston. While technically true, this observation clouds the picture of what happened on the West Fork. The West Fork sustained 2.5x more damage than the East Fork and the main body of the lake COMBINED. (See Page 14). Survivor interviews suggest that much of that damage did not happen until the release from Lake Conroe!

Conclusion: Multiple Mitigation Measures Needed

That extra 79,000 cfs underscores the need to:

  • Temporarily lower the level of Lake Conroe during the peak of hurricane season
  • Enhance the carrying capacity and velocity of the West Fork through dredging
  • Add upstream retention that helps offset Lake Conroe releases
  • Add flood gates to Lake Houston.

The last item would increase the release rate of the Lake Houston dam during a major storm. The additional discharge capacity of the ten gates proposed by Mayor Turner could easily equal the 80,000 cfs discharged from Lake Conroe, eliminating a bottleneck on the river.

Of course, if we get another Harvey, many people will flood. No surprise there. But these measures should help reduce the damage, and perhaps eliminate it when we have smaller events, such as the Tax and Memorial Day Floods of 2015 and 2016.

Posted 6/5/2018 by Bob Rehak

280 Days since Hurricane Harvey

Harris County Flood Control Solicits Ideas for Flood Bond Package on New Portion of Website

Harris County Flood Control District has just launched a new portion of its website designed to explain the proposed $2.5 billion flood bond package. Residents will go to the polls on August 25, the anniversary of Hurricane Harvey, to vote on the package. For details about the bond package, access the site at https://www.hcfcd.org/bond-program/.

The site is organized by all watersheds in Harris County. For people new to the Lake Houston area, we live within the San Jacinto watershed. Within each watershed, the site also talks about:

  • Potential project types
  • Community engagement meetings
  • Community input
  • Frequently asked questions

One of the more interesting features of the site is an interactive map with icons representing the locations of potential projects. Clicking on an icon reveals the type of project under consideration at that location, the number of people affected and more.

Preliminary map of projects currently under consideration within the San Jacinto River Watershed.

Transparency and Equity Among Goals for Flood Bond

Remember several important things: In addition to flood mitigation, two goals of this project are transparency and equity. The county wants to ensure that the bond money helps each watershed throughout the area, and that money is spent in ways that will help the largest number of people and yield the greatest benefit. That’s why you see the population numbers for each watershed and the number of people affected by each project as you click on icons throughout the map.

More Projects Than Dollars To Do Them

The county has far more potential projects than dollars. Some projects currently under consideration may not make the final cut. Likewise, other projects not yet listed could make the final cut. According to Matt Zeve of Harris County Flood Control, “Our staff is working furiously to define projects for the bond.”

Community Input Meeting for Flood Bond on June 14

Zeve says the County is also soliciting citizen input through community meetings and the website itself. Mark your calendar. One of the first meetings will be in Kingwood at:

Kingwood Community Center
4102 Rustic Woods Drive
Kingwood, Texas  77345

June 14, 2018
6 p.m. to 8 p.m.

Citizens can also submit input through the website.

“The Harris County Flood Control District accomplishes its mission by working with our partners and local stakeholders to evaluate, develop, and implement flood damage reduction plans and then perform long-term maintenance of drainage infrastructure,” says the site.

Flood damage reduction plans and projects can include:

  • Modifications of streams and bayous to increase the amount of stormwater they carry
  • Creation of detention basins to store excess stormwater
  • Nonstructural flood mitigation tools
  • Any combination of the above

Types of Flood Bond Projects Currently Under Consideration

Currently, the vast majority of projects fall into the following categories. Types of projects eligible for bond funding include:

  • Voluntary Home Buyouts – The purchase of flood-prone structures from willing sellers in areas that are too deep in the floodplain to benefit from structural flood risk reduction projects, or in areas where flood risk reduction projects are not feasible.  This process includes the demolition of the structure and relocation of the seller to higher ground.
  • Storm Repair – Major maintenance projects that restore the designed function and capacity of a channel or stormwater detention basin.
  • Subdivision Drainage Improvement – Partnership projects with the Harris County Engineering Department and a Municipal Utility District to provide drainage improvements to subdivisions in unincorporated Harris County.
  • Local Projects – Flood risk reduction projects such as channel modifications or stormwater detention basin construction using only Harris County Flood Control District funds.
  • Partnership Projects – Flood risk reduction projects such as channel modifications or stormwater detention basin construction using a combination of Harris County Flood Control District funding and funding from local, state, or federal partners such as the Federal Emergency Management Agency.

Prioritization of Projects

Make sure you read the Frequently Asked Questions. One asks, “How will projects be prioritized?” Answer: “High on the priority list are construction-ready projects with federal funding partners (such as the U.S. Army Corps of Engineers and the Federal Emergency Management Agency) that give the County “the most bang for its flood control buck.”… Consideration is also given to areas that have a lower level of current protection as compared to other areas in the county.”

The county will give highest consideration to projects that meet the following criteria:

  1. Provides the greatest potential flood risk reduction benefits relative to the community’s population
  2. Causes NO increase in existing flood risks upstream or downstream
  3. Offers potential for multiple benefits, in addition to flood risk reduction
  4. Features long-term viability and relatively low maintenance
  5. Includes a clearly defined drainage issue and flood risk reduction benefit
  6. Uses readily available, proven engineering techniques and industry standards
  7. Poses NO undue burden on disadvantaged communities
  8. Minimizes adverse impacts on the environment

Submit Your Flood Bond Ideas Now

If you have ideas to contribute, submit them now so that they can receive the full consideration they deserve. Remember: when it comes to “equity,” historically the San Jacinto watershed has received 0% of flood mitigation budgets, but we suffered 13% of the damage in the region during Harvey. For an excellent discussion of equity and needs throughout the region, see the Greater Houston Flood Mitigation Consortium’s report.

The consortium’s report provides an excellent summary of the needs of the San Jacinto watershed.

Posted on May 31 by Bob Rehak. Thanks to Clay Crawford the tip.

275 Days since Hurricane Harvey

 

New River Gages Will Improve Forecast Accuracy and Warning Time

New upstream river gages will improve accuracy of forecasts and provide more warning time in advance of floods.

The Harris County Flood Control District (HCFCD) will begin installing several new river gages this month. They should improve the accuracy of forecasts and the warning time we receive in advance of floods. HCFCD plans to install four new gages upstream of the Humble/Kingwood area and one in Lake Houston. In addition, one of HCFCD’s current gages already in Kingwood will be replaced and relocated to a new position.

New Locations for River Gages

According to Jeff Lindner, Director Hydrologic Operations, Division/Meteorologist of HCFCD, the five new river gages will be installed at:

  • West Fork of the San Jacinto River at SH 99
  • Peach Creek at FM 2090
  • East Fork of the San Jacinto at 2090
  • Caney Creek at FM 2090
  • FM 1960 over Lake Houston

Replacement for Kingwood Country Club Gage

Lindner also says that an existing river gage on the West Fork of the San Jacinto at Kingwood Country Club will be replaced and move about a mile downstream to the West Lake Houston Parkway bridge. HCFCD will remove the Kingwood Country Club gage once the West Lake Houston Parkway gage is fully operational. The country club gage has had reliability problems. Historical data from the country club gage will also be migrated to the database associated with the West Lake Houston Parkway gage.

Linked to Harris County Flood Warning System

The new river gages will give forecasters a more complete picture of what is happening within the San Jacinto watershed during floods. They will be tied into the Harris County Flood Warning System, which shows rainfall totals, channel status and water levels at different locations. The additional gages should also play a role in future enhancements of the flood warning system, such as near real-time inundation mapping and roadway flooding.

Posted by Bob Rehak on May 10, 2018 

254 Days since Hurricane Harvey

Montgomery County, Harris County Flood Control and SJRA Working on Funding Agreement for Flood Control

(April 17, 2018) Montgomery County, Harris County Flood Control District and the San Jacinto River Authority are finalizing an agreement for a $2.5 million study that will improve the region’s flood notification capabilities and identify specific flood control projects.

The Harris County Flood Control District submitted the grant application to the Texas Division of Emergency Management on April 16th.

Thanks to Gov. Greg Abbott, up to $1.875 million in federal funds could be allocated for the study if the grant is awarded through FEMA’s Hazard Mitigation Grant Program. It requires a 25 percent match; if the full $2.5 million is received, the local match would be $625,000. Montgomery county, SJRA and Harris County Flood Control would share that matching cost.

“With this study we will gain a better knowledge of our Montgomery County streams and watersheds, a more complete flood warning system, and the ability to identify specific projects that could reduce the risk of flooding in the future,” Montgomery County Judge Craig Doyal said.

San Jacinto River Watershed Flow Rates

Where Water Came From During Harvey

The goals of the study are to:

  • Prepare a plan to integrate flood warning information from HCFCD, SJRA, MCO, and COH into a shared system that can be utilized by all parties to make informed decisions; it includes expanding the flood warning system network.
  • Coordinate with flood responders including Harris County Office of Emergency Management (OEM), Montgomery County OEM, SJRA, City of Houston, and potentially others, such as the Harris County Flood Control District’s Hydrologic Operations Department, to develop a consistent communications protocol and action plan.
  • Recommend strategies to reduce flood risk and prepare a plan to implement the recommendations. Flood damage reduction options will likely include large regional detention ponds, channel improvements, vegetation and sedimentation removal, and property buy-outs.
  • Develop programs and/or materials that educate the decision makers and the public on the extent of the San Jacinto River Basin, general drainage patterns, maintenance programs for the San Jacinto River and its tributaries, potential flood reduction projects, and information relating to major flooding in the San Jacinto River watershed.

The proposed study would examine the entire San Jacinto River watershed, including Cypress Creek, Spring Creek, Peach Creek, Caney Creek, Lake Creek, the east and west forks of the San Jacinto and others. Review the scope of the project here.

If this cooperative project gets underway soon, it will mean that survey work on the East Fork of the San Jacinto can begin while the U.S. Army Corps of Engineers dredges the West Fork between I-69 and Lake Houston. Concurrent work will speed up flood mitigation.

Posted April 20, 2018, 234 Days Since Hurricane Harvey