Ideal condition of property for flood-mitigation land bank.

Create Land Bank for Future Flood-Mitigation Projects

Creating a land bank for future flood-mitigation could reduce mitigation costs, speed up projects, and protect the lives and homes of millions.

When we should acquire land for future flood mitigation.
When we usually try to acquire it.

Why Flood Mitigation Takes So Long and Costs so Much

Five and a half years after Harvey, officials are still struggling to finance many flood-mitigation projects. Part of the issue has to do with high land-acquisition costs for large, stormwater detention basins and for widening channels.

The San Jacinto River Basin Master Drainage study recommended 16 such projects in the upper basin. The plan includes 10 large regional detention facilities comprising approximately 229,000 ac-ft and six channel projects covering about 38.5 stream miles. Total cost: $2.9 to $3.3 billion (including construction). Land acquisition comprises a large percentage of that total. To put that in perspective, 229,000 acre feet is more than half the capacity of Lake Conroe. And 38.5 miles is exactly the distance from downtown Conroe to downtown Houston. And the cost totals more than Harris County’s 2018 flood bond.

Acquisition costs can vary greatly depending on whether the land is rural or urban; in a flood plain or not; wetlands or not; at a low or high elevation; distance to market; highway access; and other factors.

Ironically, the SJRA studied some of the same recommended detention basins along Spring Creek and its tributaries more than almost 40 years ago. A 1985 study on the Upper River Basin included a chapter on planning. It recommended…

“Right of way and reservoir land acquisition should occur while the land is open and available.”

1985 San Jacinto Upper Watershed and Drainage Improvement Study

Had people only listened, taxpayers might have saved a billion dollars or more. Land costs then were a small fraction of today’s. Only 1.8% of the watershed was developed. So why didn’t the interested parties start buying the land back then?

How Benefit/Cost Ratio Can Disincentivize Planning

Even though the costs were far lower, the benefits of buying farm or timber land were even lower still. Developments had to creep much closer before the Benefit/Cost Ratios increased enough to justify the expenditures. But of course, at that point people were already flooding or in danger of flooding. Now, repetitive payouts from the National Flood Insurance Plan help document the “benefits” of buying the land.

So why not create a land bank for future flood mitigation projects?

  • Buy the land when it’s cheap.
  • Put it “in the bank.”
  • Build detention basins on it when needed.

Land-Bank Precedents

There are precedents for this idea.

  • USDA started its Soil Bank in 1956. Basically, it pays farmers to take land out of production to support crop prices and farm income while preserving soil.
  • Land banks around the world acquire, hold, manage, and sometimes redevelop property for productive use and to meet community goals, such as increasing affordable housing or stabilizing property values.
  • Wetlands mitigation banks help preserve valuable wetlands to mitigate damage associated with new developments
  • HCFCD’s Frontier Program buys up land in rural areas, then develops flood mitigation projects on it. The District sells “detention capacity” to developers to help reduce its costs. This also ensures sufficient capacity for planned developments and optimum efficiency for flood-control projects.

In a similar vein, why not create land banks for flood-mitigation?

The genesis of the idea came from an observation about the two areas under consideration now for two floodwater detention basins on Spring Creek.

Forty years ago, when these projects were first studied, the benefit/cost ratio didn’t justify the purchase. Fast forward.

Benefits of Land Bank

Now, we’re looking at purchasing the same land, but because of inflation and development, the land cost is vastly higher. Had the land been purchased and “banked” way back then, the results would have been:

  • Reduced flooding
  • Reduced damages
  • Reduced costs
  • Floodplains preserved
  • People out of harm’s way.

By waiting until land is developed and people flood, we get to pay twicefor their land and for their damages through the NFIP. And project length can drag out for decades.

To be eligible for the proposed flood-mitigation land bank, the land would have to be:

  • Near a stream or river
  • Suited for building flood-mitigation projects (i.e., have the right topography)
  • In or around growing areas, such as Houston, where it would be needed for flood mitigation in a reasonable number of years.

If it contains forests or wetlands, it gets bonus points because its already reducing flooding.

In summary, the idea is to reduce future costs by purchasing land (at market rates) when it’s cheap. It has the added benefits of:

  • Preserving floodplains, wetlands and forests
  • Preventing flood damage
  • Shortening the time needed to develop mitigation projects

How Much Flood Damage Could Have Been Prevented?

The United States needs to re-engineer its flood-mitigation business processes. Flood mitigation takes costs too much and takes too long because we wait too long.

The San Jancinto River Master Drainage Plan released in 2020 points out significant flooding in 1940, 1960, 1973, 1994, 2016, 2017, and 2019 along with numerous other smaller flood events. We’ve been studying the problem for more than 40 years without actually mitigating it. A flood-mitigation land bank could help reduce costs speed up mitigation, and protect people before they flood.

It would be interesting to calculate how much damage could have been prevented in the last four of those floods had all the projects in the 1985 plan been implemented.

Posted by Bob Rehak on 12/28/2022

1947 Days since Hurricane Harvey