Greens Bayou Watershed FAQs

A maintenance project repairs or maintains what already exists.

A capital project expands or improves the current drainage system.

They can be the same.

“Bond” refers to the method of financing – the voter-approved, $2.5 billion 2018 Bond Program. Before there was a Bond Program, the Flood Control District had a dedicated Capital Improvement Program (CIP) of about $60 million per year to design and build countywide flood risk reduction projects, including the studies that led to those projects. A “capital project,” is a project that provides new or higher-capacity flood risk reduction infrastructure, rather than a project to repair or maintain what already exists.

A “bond project” is any project financed by the 2018 Bond Program. Bond projects may include:

• Flood risk reduction projects, also sometimes referred to as “capital projects”
  
• Major or large-scale maintenance projects
  
• Land acquisition
  
• Regional drainage studies
  

So, a bond project is often a capital project. A capital project can be a bond project or financed in some other way.

Now that bond funds are available, the $60 million per year previously earmarked for the CIP will go toward the increased cost of operating and maintaining an expanded drainage system.

Engineered, man-made channels are typically built with an established/documented depth and width. Let’s call that Original Configuration A. Over time, a portion of that depth and width may be partially impacted with layers of sediment and other material that ends up in drainage channels, such as vegetative debris and trash. Channels can also erode over time. This erosion could be a source of material in a channel. Let’s call that Eroded Configuration B.

While sediment generally tends to shift each time there is a major rain event, causing little impact on flood risk, in extreme cases this accumulated material potentially could reduce “channel conveyance,” which is the channel’s ability to move stormwater. Erosion of the channel side slopes could also potentially impact channel conveyance.

A maintenance project removes the sediment and repairs erosion, restoring channel conveyance and returning the channel to its Original Configuration A. This is potentially better for stormwater conveyance than Eroded Configuration B, but it does not widen or deepen BEYOND the Original (engineered) Configuration A.

In other words: Let’s say a channel is originally designed and built with a 1 percent (100-year) level of service. Accumulated sediment or erosion reduces that level of service to something less than the 1 percent (100-year) level of service. Removing the sediment and repairing the erosion allows the channel to carry more stormwater than it did WITH the sediment or erosion, but it is still no more than the original 1 percent (100-year) level of service.

Maintenance is positive, but it has limits.

Maintenance projects, in general, do not require the same degree of environmental permitting and mitigation as channel widening/deepening/straightening/concrete-lining, because maintenance projects do not alter the channel’s original configuration.

Maintenance can also take place on a non-engineered, natural channel, but that is a much more rigorous, time-consuming process, because of environmental permitting and compensatory mitigation requirements.

As discussed above, the different requirements for environmental due diligence between a capital project (to reduce flooding risks) and maintenance project (to restore a channel to its original configuration) place them on very different timelines – sometimes years apart.

Funding levels before the 2018 Bond Program resulted in deferred maintenance on many channels in Harris County. In some cases, now that bond funding is available, the Flood Control District has chosen to move ahead with projects that can be done now, such as Major Maintenance. Meanwhile, more extensive pre-project work on capital projects that will increase the level of service and reduce flooding risks (which could take years) continues on a separate but coordinated track.

No. All watersheds in Harris County – including the Greens Bayou watershed – are at risk of flooding. That is because Harris County is flat, has impermeable clay soils, and is prone to severe rainfall, including tropical storms and hurricanes. While the $2.5 billion 2018 Bond Program will reduce flooding risks across the county – including in Greens Bayou – it will not eliminate those risks entirely. Even with billions of dollars of investment, there would still be flooding risks. Any watershed in Harris County can flood, given enough rain over that watershed. Many projects from the Bond Program are already underway and will be completed as soon as possible in the next months and years. It will take approximately 5-10 years to complete the entire program.

The Flood Control District’s stated mission is to “provide flood damage reduction projects that work, with appropriate regard for community and natural values.” The Flood Control District supports the multi-use of its facilities for recreation and open space, as long as there is a funding partner to build and maintain those amenities, and those activities do not interfere with the property’s primary flood risk reduction purpose.

The Flood Control District’s Policy, Criteria, and Procedure Manual states “The Flood Control District recognizes the opportunities presented by Flood Control District facilities to enhance both community and natural values. Consequently, Flood Control District supports and encourages such multi-use functions as trails, green space, parks, greenway or corridors, stormwater quality facilities, practice fields, and other recreational and natural features provided they are compatible with the primary function of the Flood Control District facility. (See related Policy XIII, Natural Environments and Habitats.)”

It is not part of the Flood Control District mission or enabling legislation to fund recreational amenities. We partner with agencies all over the county who want to fund and maintain trails, ball fields etc. along our bayous or at stormwater detention basin sites. This is a significant benefit to those agencies, because they do not have to spend their money to acquire new park and open space land.

Partner agencies who seek to build/maintain recreational amenities on our flood control property sign a written agreement acknowledging the property’s primary flood control purpose. Meanwhile, the Flood Control District strives to make their job easier by close coordination during the engineering design and construction phases of our projects.

Sometimes, during the project design stage, it is determined that an available site is too small, and the need for flood risk reduction is too great, to allow some of the land to be used for parking lots, ball fields, etc. This is a case-by-case determination.

For those reasons, we can’t make a blanket statement that ALL facilities will have recreational amenities. However, we do support the multi-use of our property, and are willing to work with appropriate sponsors to achieve that goal.

The Flood Control District also has a robust Tree Planting Program, and plants native wildflowers on flood control property. We do this because it provides maintenance benefits, and we conduct the plantings in a way that does not interfere with the property’s primary flood risk reduction purpose. Site beautification is an added benefit, but it is not the primary goal.

No. Development regulations are enacted by the governing jurisdiction for each area. That is the underlying municipality, such as the City of Houston, or Harris County government for unincorporated Harris County. The Flood Control District is not the floodplain administrator, nor do we have development codes. The Flood Control District is an agency of engineers and support staff that builds flood risk reduction projects and maintains this infrastructure.

It is the floodplain administrator that decides on land use and flood mitigation requirements, such as stormwater detention etc. Of course, the Flood Control District has expertise to offer in these areas, but the ultimate permitting decision is made by the permitting authority of the underlying municipality/county, as governed by elected council members, commissioners etc.

The Flood Control District does provide technical reviews for all development projects that outfall into or otherwise impact its drainage infrastructure, but this review does not involve deciding how land may be used, enacting development requirements, or permitting new development. This review makes sure the permitted development is to our minimum standards, and that there is no impact upstream or downstream in stormwater levels because of the new development that touches our infrastructure.

Each new development (of greater than one acre) must perform a drainage study, signed and sealed by the development’s design engineer, who is ultimately responsible for the accuracy of all calculations and the determination of no adverse impact.

If a development follows the requirements in place at the time that the project is permitted, the Flood Control District cannot “stop the development.”

One qualification: The Flood Control District has a floodplain preservation program that seeks to purchase and remove floodplain land from possible future development, or to purchase and clear the land if necessary and cost-beneficial. A determination of need and necessity by its governing body is required before the Flood Control District can use the “eminent domain” legal process to force a property owner to sell.

Developers are required to follow rules put in place to ensure that new development will not increase the risk of flooding for anyone else. In the case of a residential development involving the importing of fill dirt, some requirements are that:

• The volume of fill to be placed in a mapped floodplain is required to be offset by an equal amount of new storage. That is, a development that brings 1,000 cubic feet of fill into the mapped floodplain must build a detention pond to hold at least a 1,000 cubic feet of water to replace the lost floodplain volume.
• If a development has the potential to change the way water flows down a channel/bayou, they must do an analysis to demonstrate that the change would not increase the flood risk for anyone else.
  
• Texas Water Code Section 11.086 also requires that the development ensure that it does not adversely affect the natural flow of surface waters around or through the development, so that neighboring properties are not affected.

The Flood Control District typically does not utilize pumps in our stormwater detention basins because of the vastly increased operations and maintenance costs associated with pump stations, as well as the risk of failure.

The Flood Control District will not rule out using pump stations in unique circumstances where the benefits provided by pumping a stormwater detention basin dry via pumps will greatly exceed the additional maintenance costs associated with the pump stations.

Municipal Utility Districts can design, construct and maintain pump stations on the basins that they own and maintain.