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Flood Damage Reduction Tools
There are many alternatives that can be incorporated for flood damage reduction. The Harris County Flood Control District utilizes a number of techniques, or primary "tools," to reduce flood damages throughout the county. Generally speaking, these tools are implemented in flood damage reduction projects. However, there are instances where some tools are used outside the realm of project implementation.
Some of the primary options the District considers for flood damage reduction are termed "structural" tools, while others are termed "non-structural" tools. There are a variety of criteria that determine which tools are most appropriate to use when implementing a project. Two of the most important criteria are how much flood damage reduction benefit is gained by the total dollars invested in the project and making sure the project selected has appropriate regard for community and natural values.
STRUCTURAL TOOLS
Channel Modification (also called Conveyance Improvements)
Channel modification is a man-made change to a channel's characteristics, typically for the purposes of reducing flood damages by increasing its overall conveyance capacity. This can be accomplished by widening and/or deepening the channel, reducing the friction by removing woody vegetation, or by occasionally adding concrete lining. It should be noted that only 6% of the channels in the county's drainage infrastructure inventory are concrete lined.
Stormwater Detention (Basin)
A stormwater detention basin is another structural tool used by the District when implementing a project. A stormwater detention basin is a large, usually excavated area of land, frequently adjacent to a channel, which is designed to receive and hold above-normal stormwater volumes. The detained stormwater then slowly drains over time out of the detention basin as water surface elevations in the receiving channel recede.
Bypass Channel
Bypass channel construction could also be a man-made change to a channel's characteristics. However, rather than necessarily increasing a channel's capacity, a bypass channel diverts excess stormwater "around" an area with restricted right-of-way or an area with sensitive environmental values. Specifically, bypass channel construction involves building a new channel that is attached to an existing channel and, as mentioned, conveying the excess stormwater runoff around its original path. Bypass channels usually "short circuit" the meander or curve of a bayou and are usually constructed in conjunction with downstream channel modifications or a detention basin.
Bridge Modification
Bridge modification is another structural tool used in flood damage reduction. It involves the replacement, extension or modification of a bridge in order to remove an impediment to flow within a channel and/or accommodate channel modifications. It can also lessen the likelihood of debris snagging on the bridge piers. If done in conjunction with channel modification, a bridge modification is typically completed first.
Levee
A levee is a physical barrier constructed to protect areas from rising floodwaters. Levees are not feasible in most cases in Harris County for a variety of important reasons. Levees typically remove valuable flood plain storage and block the ability of the channel to move water. There are also concerns with rainfall that falls within the levee itself. Most importantly is the possibility for catastrophic and sudden failure under extreme flood events, potentially resulting in loss of life and total destruction of property.
NON-STRUCTURAL TOOLS
Buyout
One of the most effective tools the District uses involves no construction whatsoever. It involves buyout and demolishing of structures that were built deep in flood prone areas where structural projects to reduce flood levels are impractical. Structures in this situation were typically built years ago before detailed floodplain maps and studies were available and before floodplain management regulations were adopted by the county and the cities in the county.
Once a flood prone house is bought and demolished, it will never incur flood damages again. The District actively pursues voluntary buyout opportunities.
> Learn more about the District's buyout activities.
"TOOLS OF THE TRADE"
There are also other so-called "tools" that are utilized in the planning process, implementation phases and maintenance of the drainage infrastructure. Those can be generally thought of as "tools of the trade," or methods and materials that may help the District's flood damage reduction projects work more efficiently with regard for community and natural values.
An example of this would be the using Cellular Concrete Mats (or, CCM) in constructing a new channel. Rather than building a solid lining with concrete, CCM is used to provide an armoring to guard against erosion while providing an opportunity to establish vegetation over its surface. Over time, holes in the interlocking blocks of concrete will naturally fill in with sediment, allowing vegetation to grow, which encourages other wildlife activity and enhances the overall aesthetics of the new channel.
Other examples of smaller tools of the trade are the use of native plants and wildflowers that beautify a project area, protect the integrity of a channel's slopes by strengthening against erosion, and also reduce mowing cycles, saving taxpayer dollars in the long run.
TOOLS FOR THE COMMUNITY
Flood damage reduction tools also exist for the community-as-a-whole, as well as individual citizens.
Floodplain Management & Regulations
In order for a community to participate in the National Flood Insurance Program (NFIP), the community is required to enforce regulations on land development projects to avoid increasing flood levels or flood hazards and to avoid creating new flood hazards. This work is performed by the local communities' Floodplain Administrators. Most of the 35 communities in Harris County, including the City of Houston and Unincorporated Harris County, have regulations that exceed the NFIP minimum standards.
Flood Proofing of Structures
Flood Flood proofing is the modification of individual structures and facilities and their sites to keep floodwater from entering. Flood proofing of structures comes in a variety methods, but the more appropriate practice for the Harris County area would be physically raising a structure above the 1% (100-year) flood level. Individual municipalities have different regulations regarding the height above the 1% (100-year) flood level, so the individual would have to consult with the appropriate municipality before raising a structure.
Flood Forecast Warning and Response Systems
Rain gage data and weather forecasts are vital tools for those providing information to a community the size of Harris County. The Harris County Office of Homeland Security and Emergency Management regularly monitors rain gages located throughout the county and local meteorologists provide real-time forecasts and updates with state-of-the-art equipment and technology. This combination helps to lessen the impact from flooding, while increasing the preparation for such an event, as much as possible.
Disaster Preparedness
Increased preparation for flooding not only lessens its impact, but may also mean the difference between life and death. A flood warning and forecast system is of little use unless the community is prepared to respond to such warnings. Community evacuation plans and family flood preparedness plans are crucial to minimizing the misery caused by a Harris County flood catastrophe.
> More information on family flood preparedness, including a downloadable and printable preparedness document.
Relief and Rehabilitation
Sometimes, no matter the amount of preparedness and forecasting, flooding can be so severe that external relief is necessary. Such was the case with Tropical Storm Allison, as well as many other flood events that have plagued Harris County. Post flood recovery can involve relief efforts from the American Red Cross, as well as financial relief from federal agencies, when a disaster has been declared by the Governor. This relief can come in the form of low-interest loans to affected citizens and grants to communities for efforts that will minimize future flood exposure. The latter could be in the form of buyout, the District's primary non-structural flood damage reduction tool. A bought out home will never flood again.
Flood Insurance
Flood insurance is perhaps the most powerful tool citizens can use to arm themselves against the impact from flooding. It is vital for individual residents and businesses in any community, especially in the Harris County area. Given our climate, flat terrain and impervious soils, Harris County (and the surrounding area) is naturally flood-prone. Homeowners insurance doesn't cover losses from flood damages, so since Harris County participates in the National Flood Insurance Program (NFIP), separate flood insurance policies may be purchased by individual citizens. The cost usually averages just a few hundred dollars per year, which is minimal compared to a three-hundred-dollar-a-month flood-related loan from the federal government. The savings in money and misery are obvious.
So, who needs to purchase flood insurance? EVERYONE!
Considering that, nationally, approximately one-third of all flood losses occur outside the mapped floodplain, and nearly TWO-THIRDS of all flood losses from Tropical Storm Allison occurred outside the mapped floodplain, the incentives to purchase a policy are clear.
Flood insurance is the most powerful tool citizens can implement to mitigate flood losses.
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Flood Insurance: One of the Most Powerful Tools for Lessening Flood Impact
Nature always fights on its own terms and periodically exacts a heavy toll in terms of property damage. A storm like Tropical Storm Allison is one we will never forget, however we can expect more storms like Allison in the future. It's just a matter of when... and where.
Even if you are not moved by the physical danger such a storm presents, consider this: Repaying a $50,000 flood-related loan from the Small Business Administration costs about $300 a month over many years, while the average flood insurance policy usually runs about $300 annually. The savings are obvious, and the peace of mind is priceless.
EVERYONE needs flood insurance!
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