In the first year since Hurricane Harvey, wheels were set in motion on many flood mitigation projects, but very little has actually changed on the ground. Below are where things stand on 12 measures designed to help reduce the risk of another major storm. Implementing them should be top priorities for Year Two.
- Additional Dredging – After Harvey, we found the San Jacinto clogged with sediment. The Army Corps of Engineers spent the last six months studying the river and prepping to dredge some of the worst blockages. Dredging should start this Thursday, September 6. However, the Corps will not address the entire river.
In fact, they are leaving the biggest blockage at the mouth of the West Fork intact because part of it existed before Harvey and FEMA money can only be used on damage that occurred during Harvey. If we can find money elsewhere to address the mouth bar before the current dredging project is completed next April, we may be able to save $18 million in mobilization and demobilization fees. But even if we manage that, there will still be approximately ten more miles of the East and West Forks to dredge. And they should be dredged regularly to prevent future buildups. Maintenance dredging has not even registered on the radar yet.
- Additional Gates for Lake Houston Dam – In Year One, a preliminary study was completed showing that additional gates could lower the level of a Harvey-like flood by 1.9 feet. An application for funding is pending with FEMA (along with 800 other projects). The benefit/cost analysis was extremely positive. Virtually everyone supports the project including the mayor and governor. Preliminary engineering studies have reportedly begun. And the County has dedicated $20 million from the flood bond to support the $70 million project (See item CI-028 on page 9). However, the source for the final $50 million remains uncertain. The ball is in the city’s and Coastal Water Authority’s court on this one. The City owns the dam and the CWA manages it. Hopefully, the Mayor and Council Member Dave Martin will have progress to report in their upcoming town hall meeting Tuesday, October 9 at 6:30 p.m. at the Kingwood Community Center.
- Ditch Maintenance – The City and County reportedly agreed to divvy up maintenance to reduce duplication of efforts. The City will focus on below-ground drainage and the County will focus on above-ground. However, the City’s legal department has not completed easements that would allow the County to begin work. The county flood bond freed up maintenance money in the the flood control district’s budget. Therefore the county could begin work on projects such as clearing Ben’s Branch immediately. The County flood bond also included $40 million for channel improvements. Work on the Huffman side of the river was approved last week and should start shortly.
- Additional Upstream Detention – The idea: to reduce the amount of water coming downstream during a flood and release it gradually after the flood. Voters approved money for building additional detention on the East and/or West Forks in the flood bond. Large tracts of land are becoming increasing difficult to find. Therefore, the County may have to focus on multiple smaller projects scattered throughout the watershed. The SJRA watershed study (see item CI-019 on page 9), which still is not fully funded, will need to be completed before the county and SJRA can identify where the most effective locations for dams will be.
- SJRA Watershed Study – Is still not fully funded or approved by FEMA. The total cost is minuscule compared to other projects, yet a draft of the proposed survey specs has been circulating since March.
- Improved Flood Awareness and Warning Systems – The County has installed half a dozen new gages that will enhance early warning capabilities. They will help river forecasters see water coming at us from father away, so we have more warning time. The county has also created a near-real-time inundation mapping system that they activate during floods. See HarrisCountyFWS.org when a flood threatens. You can see down to the block level where water is spreading. The SJRA is also installing more gages farther upstream. Those should enhance awareness and warning time even more.
- Improved Inter-Agency Cooperation and Public Notification Systems – Texas House and Senate hearings held in the wake of Harvey identified these two areas as needing improvement – everywhere, not just in the Lake Houston area. Evacuation warnings did not reach people in time. Many were caught sleeping as floodwaters rose in their homes. There were two issues: a breakdown in the chain of communication and systems that can wake people up in emergencies, especially when the power is out. It worries me somewhat that we’re focusing so much of our time and attention on upgrading Internet systems. The Internet, cell towers, and power are among the first casualties of a storm. Whatever happened to good old sirens?
- Flood Plain Map Updates – Harvey demonstrated that our flood plain maps are obsolete and need to be updated. Of the 154,170 homes flooded, 48,850 were within the 1% (100-yr) floodplain, 34,970 within the .2% (500-yr) floodplain, and 70,370 were outside of the 1% (100-yr) and .2% (500-yr) floodplains. 64% of the homes flooded did not have a flood insurance policy in effect. This scary statistic resulted primarily from two things: bad assumptions about flood frequency and relentless upstream development. The former blindsided us. The latter increased the scope and rapidity of downstream flooding. Harvey was the fifth so-called 500-year storm to hit the Lake Houston area in 23 years. Our flood plain maps desperately need updating. So do our statistical assumptions. Finally, people need to wise up about flood plain maps. Being on one side of a line or another does not guarantee immunity from flooding. People should not think of boundaries on flood plain maps as binary. In reality, the boundaries are wide and fuzzy, much like the cone of uncertainty for hurricane path predictions.
- Development Regulations – Upstream development causes downstream flooding. It overwhelms systems established decades ago. No one seems to have an appetite for regulating upstream development. So people downstream must build new homes higher, raise older homes, improve drainage systems, and move farther back from rivers, bayous and drainage ditches. We have to quit pretending that so-called 500-year storms happen 499 years apart and start building realistic assumptions into building permits.
- Sand Mine Regulation – Sedimentation in the San Jacinto River didn’t cause flooding, but it exacerbated it. A large portion of that sedimentation came from 20 square miles upstream from us. All but one mine is built in the floodway. If we want to reduce dredging intervals and costs, we should consider pushing these mines farther back from the river. There’s plenty of sand outside of the floodway. However, the miners will resist this. It will be a major political battle. The legislature meets in January. That doesn’t give us much time. TACA has already quadrupled their lobbying budget to fight us.
- Project Managers – Flood mitigation is like a jigsaw puzzle that moves while you’re putting it together. It’s also like trying to make committee decisions with committees that never meet. You have multiple decision makers at City, County, State and Federal levels, none of whom are accountable to each other, and many of whom have conflicting interests. As a result, projects drift. Details get lost. Approvals don’t come in time to save money. One party may not even be aware of the deadlines that another faces. In such cases, project managers can make a huge difference. They constantly monitor all the moving parts of a project and prod people to make sure milestones are met. Good project managers can increase productivity by 20%. If you’re spending $2.5 billion on flood mitigation, that could save half a billion dollars. Each watershed should have its own certified project manager who champions that area. Too many details are getting lost in the shuffle, holding projects up, and potentially escalating costs, as with the mouth bar.
- Lowering Lakes Temporarily and Seasonally – The City of Houston and SJRA made the only physical change since Harvey that will help protect us from flooding. The SJRA board voted to lower the level of Lake Conroe during the rainiest months in spring and the peak of hurricane season by up to two feet. The City also started lowering the level of Lake Houston in advance of major storms. If the National Weather Service predicts greater than three inches of rain within the San Jacinto River basin in a 48-hour period, Coastal Water Authority will lower Lake Houston to by one foot to 41.5 feet. These measures create more capacity within Lakes Houston and Conroe to absorb water that might otherwise flood us. The measures will be re-eavaluated once dredging is complete and more floodgates have been added to Lake Houston.
Posted by Bob Rehak on September 4, 2018
371 Days since Hurricane Harvey