Need for Sediment Management Planning

Sand and sediment clog our rivers and lake. “Dredge!” you say.

“Not that simple,” say the experts. “Who will pay for it? How much should we dredge? Where will the sediment go?”

That’s why we need planning for sediment management. We need to dredge the worst parts of the river now; the U.S. Army Corps of Engineers (USACE) has already started that as an emergency project. But we also need to dredge other parts of the river that are not quite critical yet. And we need to figure out how to do all this on a regular basis so that it never gets this bad again.

A giant sand dune has formed at the mouth of the west fork of the San Jacinto. It is not being addressed by the Army Corps dredging project but should be. Thousands of homes upstream from this massive blockage flooded during Harvey.

Sediment Management Challenges That Lie Ahead

I have talked about these issues with experts from Harris County Flood Control and USACE. Both say planning is crucial to a successful maintenance dredging/sediment management program. One provided this document: Galveston-Bay-Programmatic-RSM-Plan-Rev-1, as an example of what we need for the San Jacinto. It’s a long document – 112 pages. But it is worth reading the executive summary, introduction and table of contents at the very least. Parts of it discuss the upper reaches of the San Jacinto. But the main value it provides is that it outlines the challenges ahead.

  •  Who will lead the effort? Who will support it?
  • How much money is needed per year? How can we budget for it? Who will share in the costs?
  • Where will the dredged materials go? How can we identify opportunities to reuse and sell them? Who will market them and how? To what extent can sales defray dredging costs?
  • What are the true life-cycle costs of the sand and sediment that miners send downstream to us?
  • How can we reduce their contribution to the problem? Is there a way to make them part of the solution?
  • How can we coordinate upstream and downstream efforts so that the entire river system flows freely?
  • How can we remove channel blockages more quickly after floods to help prevent additional flooding?

All of these are difficult questions. Starting such an extensive program is like starting a new business.

Budgeting Comes First

A business plan and budgeting are the first issues we need to address. Where will the money for all this come from? Without answering that first, everything else is moot.

So who are the stakeholders?

  • City of Houston – Ensuring the future of Lake Houston is essential to ensuring the future of the City. It’s the City’s main source of water.
  • Harris County Flood Control – Half of the people that live in the county, live in the City.
  • San Jacinto River Authority (SJRA) – The State created the Authority back in the 1930s to impound water and protect people from flooding. Those missions were recently reconfirmed by the Governor.
  • Coastal Water Authority – CWA is the contract operator for Lake Houston Dam and Reservoir. They sell water just like SJRA and can raise money thru water rates to fund flood mitigation. Their enabling legislation mentions drainage and flood responsibilities – same as SJRA.
  • State of Texas – This region has a quarter of all the people who live in the state. Nuff said.

Expecting all costs to be covered by the Harris County Flood Bond in perpetuity is just wishful and foolish thinking. The bond is for capital projects, not ongoing maintenance. You might be able to justify the first dredging as “channel improvements.” But after that, for the sake of the community, we need to find a way to make this program sustainable. Paying interest for ongoing operations is unwise.

Cost Sharing and 5-Year Intervals Can Make It More Doable than Avoidable

In 2000 Brown & Root, recommended dredging every 5 years – a perfect match for a venture with five partners. If each budgeted one fifth of the cost annually, and you did only one fifth of the job each year, this just might be more doable than avoidable. (Avoidance seems to have been the preferred approach in the past.)

We can’t budget sediment management forever on an emergency basis. That’s like using an emergency room for basic medical care. It’s probably not the best idea, nor the most cost effective. So let’s begin the dialog with stakeholders. As Grandma used to say, “An ounce of prevention…”

Posted on July 13, 2018 by Bob Rehak

318 Days since Hurricane Harvey