Houston Floods. It's that simple, and it floods here often in some places more than others . Customers can get two PDF files about the last major flood. There are also long periods of drought when the ground cracks from a lack of rain. There is no viable bedrock in this region and the soil is expansive due the high content of clay and "black mumbo"..
Floods kill people and destroy homes in many parts of the United States every year. Federal agencies estimate that an average of over 125 people die every year in the United States because of flooding, although losses vary widely from year to year. Property damage ranges into the billions each year, and has been rising in recent decades.
Of course the live video of a family clinging to their car in a swollen river as rescuers winch down from a helicopter is so compelling that few viewers can change channels. But flooding is also worth covering because if people are informed, they can make decisions which will save lives and reduce property loss.
As the deadliest and most damaging of U.S. weather hazards, floods have long been the focus of dreadful fascination by the public. Sometimes it is the scale that awes us—as in the legendary Mississippi River flood of 1927. Sometimes it is the sudden lethality—as in the 1889 Johnstown Flood that killed more than 2,209 people.
Flooding actually occurs from a range of causes and conditions—not always the ones that first come to mind. For example, few people appreciate that inland flooding has been the cause of more than half the deaths arising from hurricanes in the last three decades. Of the 56 people who died in 1999's Hurricane Floyd, 50 drowned from inland flooding. Torrential rains can accumulate when a storm becomes "stalled" in a certain location, even hundreds of miles from the coast.
Of course, river flooding is the kind we think of most commonly. Heavy rains or rapid snowmelt on upstream watersheds cause rivers to rise—more so at chokepoints or where tributaries converge.
Coastal flooding is also very common. In many places, coastal land is very close to sea level, and therefore vulnerable. During hurricanes or other large storms, waves may be much higher than normal, and super-low atmospheric pressure often forces sea level to rise a dozen feet or more above normal in a "storm surge." When violent surf and storm surge coincide with normal high tides, the results can be catastrophic.
Less often thought of are the floods that can result from the failure of dams, impoundments, or other regulatory systems. The Johnstown flood is an example. There are more than 76,000 dams in the National Inventory of Dams, and probably others uncounted.
FEMA, which runs the National Dam Safety Program, says there are 10,400 high-hazard and 13,300 significant-hazard dams in the United States FEMA says "Emergency Action Plans" are essential for all of these dams, but that so far some 70 percent still do not have them. According to the National Performance of Dams Program at Stanford University, "1,595 significant hazard dams are within one mile of a downstream city." To keep things in perspective, it is worth remembering that many dams offer major protection to the public from flood control.
Floods can be a concern even in arid and semi-desert parts of the country, such as those in the West. Flash floods there are more of a danger because people do not expect them. Arroyos and washes, or normally dry streambeds and gullies, can fill with water within minutes or seconds during an intense downpour. Because roads often follow their contours, they may present danger to people in cars.
A flash flood is really any sudden, severe flood event, and they can have a variety of causes—although large sudden downpours are the main ones. The effects of a downpour are worsened when terrain will not absorb water. Reasons vary: soil type (e.g. clay), lack of vegetation, steepness, extensive pavement (urban areas), frozen or ice-covered soil, or the saturation of soil by previous rains.
Another cause of flooding in some areas is ice jams. In colder northern areas, ice sheets form on the surface of a river during cold winter months of low flow. Warmer weather and higher flows cause the ice to break up into huge slabs that the current pushes downstream. When these slabs pile up against some obstacle, they form a dam that causes water to pool upstream—and flooding results.
Floods typically get the most headlines when waters are about to crest. But there are important post-flood stories that need telling as well. Members of a flood-stricken community need all kinds of information to avoid pitfalls and deal with problems. For example, failure of normal sewage and drinking water systems means people need advice about how to find safe drinking water. They need to avoid pumping out flooded basements too quickly to prevent water pressure from destroying foundations. They need to understand and address the problems of mold and mildew in waterlogged buildings. And of course they need advice on how to connect with disaster-aid agencies.
The federal government spends several billion dollars on disaster aid in any given year—a major share of it going to communities hit by flooding. Almost everybody agrees that people flooded out of their homes need immediate help.
But important issues arise over whether money is better spent preventing losses before-the-fact than compensating for them after-the-fact. And it is also an issue whether taxpayer money spent merely to compensate for flood loss does not encourage, even subsidize, people to remain in harm's way.
Federal disaster aid funds temporary housing for people while damaged homes are being repaired, money to help repair homes, grants for basic living expenses, etc., when these are not covered by insurance. There are also low-interest loans to families, farms, and businesses to help them repair or replace lost property—as well as unemployment aid, tax breaks, legal services, and crisis counseling. Another kind of aid goes to local governments, to help them clean up debris and restore facilities like roads, utilities, public buildings, and parks.
A different set of FEMA programs and funding are aimed at preventing and mitigating flood hazards. The most dramatic involves feds partly funding buyouts of flood-damaged property—to help people buy houses on dry land and the bought property reverting to uses like parks under ownership of local government. Other federal funds support measures like physically moving houses beyond the floodplain, elevating them on stilts, or floodproofing them.
The most important federal effort to address longer-term flood problems is the National Flood Insurance Program. People in flood-prone areas find it nearly impossible to get ordinary insurance against flooding—precisely because they are in flood-prone areas. The NFIP involves a bargain from which both sides benefit. Local communities must qualify by adopting and enforcing floodplain management ordinances (which might, for example, forbid building new houses in floodplains). This reduces future flood damage and federal liability for disaster aid. In return, the federal government backs flood insurance offered in these communities by participating private insurance companies. National Flood Insurance is offered in more than 19,000 U.S. communities.
Flood issues spur many policy and political debates at both the local and national levels. Although the NFIP insists that the program pays for itself, critics often charge that it is federally subsidized.
The debate is likely to emerge again as Congress and the President struggle with the 2002 budget. The Clinton administration, following the great Mississippi-Missouri flood of 1993, shifted a much greater emphasis in funding toward mitigation and buyouts, to the applause of environmentalists. President Bush's budget proposal would de-emphasize mitigation in favor of more direct (and politically popular) disaster aid.
In August 2002, the National Safety Council partnered with the National Oceanic and Atmospheric Administration (NOAA) and National Weather Service (NWS) on safety and health initiatives surrounding the Advanced Hydrologic Prediction Service (AHPS). The result: a new AHPS brochure that increased awareness of the Weather Service’s improved river and flood forecasting capabilities and water information across America.
Since then, we’ve continued our partnership to produce:
Click here to find additional information on storm proofing including wind forces.
Click here to View Flood
Plane Maps from www.efloodmaps.coma division of Dodson and associates.
Harris County Montgomery County Fort Bend County
Also try these links:
Consequences of Land Subsidence
InSAR-Detected Inland Subsidence, 1996
InSAR-Detected Coastal Subsidence, 1996–99
Integrated Monitoring in the 21st Century
1. Map showing subsidence study area and extent of two satellite scenes, Houston-Galveston Bay area, Texas
2. Map showing extent of subsidence in the Houston-Galveston Bay area during 1906–95
3. Map and graphs showing that during 1978–95, subsidence in areas southeast of Houston essentially ceased as pumpage there decreased; and subsidence continued in areas northwest as pumpage there increased
4. Photograph showing land subsidence of 5 to 7 feet in a residential area in northern Houston exacerbated flooding in June 1989
5. Map showing areas of interferograms shown in figures 6–9
6. Wrapped and unwrapped interferograms for the western Houston area for the 11.5-month period January 13–December 29, 1996
7. Unwrapped interferogram for the Texas City area for the 31-month period August 27, 1996–March 29, 1999
8. Unwrapped interferogram for the Sagemeadow-Johnson Space Center area for the 31-month period August 27, 1996–March 29, 1999
9. Unwrapped interferogram for the Baytown area for the 31-month period August 27, 1996–March 29, 1999
for the area served by the NWS Forecast Office in Houston/Galveston
Air Quality Problems Caused by Floods
How Are Floodwaters an Indoor Air Quality Problem?
During a flood cleanup, the indoor air quality in your home may appear to be the least of your problems. However, failure to remove contaminated materials and to reduce moisture and humidity can present serious long-term health risks. Standing water and wet materials in the home can become a breeding ground for microorganisms: bacteria, mold, and viruses. They can cause disease, trigger allergic reactions, and continue to damage materials long after the flood.
What Are the Health Effects?
Standing water is a breeding ground for microorganisms, which can become airborne and then can be inhaled. When floodwaters contain sewage or decaying animal carcasses, infectious disease is of concern. Even if the water appears clean, microorganisms can cause allergic reactions in sensitive individuals. For these health reasons, and also to lessen structural damage, all standing water should be removed as quickly as possible.
Excess moisture in the home is an indoor air quality concern in several ways:
- Microorganisms in floodwaters may present a health hazard. These organisms can penetrate deep into soaked, porous materials and later be released into air or water. Coming in contact with air or water that contains these organisms can cause illness.
- High humidity and moist materials provide ideal environments for the excessive growth of microorganisms that are always present in the home. These situations may result in additional health concerns such as allergic reactions.
- Long-term increases in humidity in the home can also foster the growth of dust mites. Dust mites are a major cause of allergic reactions and asthma.
How Can I Reduce the Moisture in My Home?
Drying out can take several weeks and microorganisms will continue to grow as long as the moisture and humidity levels are high and as long as there are damp items in the home. Materials such as carpet that cannot be adequately dried out should be discarded. Steps you can take to help reduce moisture in your home include the following:
- Open the doors and windows, especially if the humidity is higher inside than outside of the house.
- Open all closets and cabinet doors to allow the air to circulate. Open drawers as soon as possible because unopened drawers may swell, making it hard to open them when they are dry.
- When the electricity is back on, turn on fans to help air out your home.
- Do not use the air conditioner or the furnace blower if they were under water. You might be blowing contaminants from sediments left from the excessive water.
- Clean or hose out ventilation ducts before using the air conditioner or furnace.
- Use a dehumidifier and/or desiccants to dry out your home.
- If the damage is extensive, you may want to call a contractor who specializes in water extraction.
What Indoor Air Problems Are Caused by Floodwaters?
Asbestos is a mineral fiber commonly used in the past in a variety of building construction materials for insulation and as a fire retardant. Some products that may contain asbestos are pipe and furnace insulation materials; asbestos and cement shingles, siding, and roofing; millboard; resilient floor tiles, the backing on vinyl sheet flooring, and floor tile adhesives; soundproofing or decorative material; patching and joint compound; certain fireproof gloves; and stove pads. However, most products made today and in the past do not contain asbestos. Asbestos can cause lung cancer, mesothelioma (a cancer of the chest and abdominal linings), and asbestosis (irreversible lung scarring that can be fatal). The risk of lung cancer increases with the number of fibers inhaled.
Asbestos, when damaged by a flood, should be repaired or removed by a professional. Repair usually means either covering or sealing the asbestos material. Covering involves placing a protective wrap over or around the material that contains asbestos thereby preventing the release of fibers. Sealing involves treating the material with a sealant that either binds the asbestos fibers together or coats the material so no fibers are released. Repair is usually cheaper than removal, but some repairs may make it more difficult to remove the asbestos later if the need arises.
Biological contaminants are or were living organisms. Common indoor biological contaminants are bacteria, molds, mildew, viruses, animal dander, house dust mites, cockroaches, and pollen. Nutrients and moisture are necessary to support biological growth. A flooded home can contain both of these conditions. Biological contaminants can trigger allergic reactions and asthma, and some can release disease-causing toxins that can damage the liver, central nervous system, digestive tract, and the immune system.
There are several ways to reduce your exposure to biological contaminants:
- Thoroughly clean and dry water-damaged carpets and building materials (within 24 hours if possible) or consider removal and replacement. If your carpet was completely underwater, it should be removed.
- Bleach (1/2 cup to a gallon of water) will remove mold and mildew from bathtubs, walls, floors and many other surfaces.
- Use a dehumidifier to keep relative humidity levels between 30 and 50 percent.
- Maintain and clean all appliances that come in contact with water. Have a professional inspect and clean electrical appliances.
- Change the filters on heating and cooling systems as specified in the manufacturer's directions.
Carbon Monoxide is a colorless, odorless gas that is produced as a result of incomplete burning of carbon-containing fuels such as coal, wood, charcoal, natural gas, and fuel oil. When houses are flooded and occupants are without electricity, people sometimes attempt to use gasoline-powered generators, camp stoves, and lanterns indoors. Using these devices indoors poses serious safety risks and is strongly discouraged. Devices that are designed for outdoor use should never be used indoors. Using these devices can result in high levels of carbon monoxide, which can cause death.
Here are several ways to prevent carbon monoxide poisoning:
- Open flues when fireplaces are in use.
- Do not use ovens and gas ranges to heat your residence.
- Do not burn charcoal inside your home.
- Use proper fuel in kerosene space heaters.
- Use unvented gas or kerosene space heaters only in well-ventilated rooms.
- Never leave a car or any engine running in an enclosed area (such as a garage).
- Use a carbon monoxide detector that meets Underwriters Laboratories Inc. standards, has a long-term warranty, and is easily self-tested and reset to ensure proper functioning.
Approximately 64 million homes, or 83 percent of the privately owned housing units built before 1980 have lead-based paint somewhere in the building. Nearly one-fifth of these residences are home to families with children under the age of seven. Lead can also come from the solder or plumbing fixtures in the home, fishing lure weights, ceramics, and bullets. A flood in the home can expose the residents to lead from deteriorating paint, contaminated soil, and dust from peeling or chipping paint. Young children are especially vulnerable. Elevated lead levels can cause brain damage, stunt a child's growth, damage kidneys, impair hearing, cause vomiting and headaches, and cause learning and behavioral problems. In adults, elevated lead levels can increase blood pressure, nerve disorders, sleep problems, muscle and joint pain, and mood changes.
You can do several things to reduce your exposure to lead:
- If the paint is not intact, it needs to be inspected for lead, and if it has to be removed contact a qualified contractor.
- Mop floors and wipe window ledges and other areas with an all-purpose cleaner.
- Make sure everyone washes their hands before meals, naptime, and bedtime.
- Keep children away from areas where paint is chipped or peeling. Stop children from chewing on windowsills or other painted surfaces.
- Children should eat a balanced diet with plenty of foods that contain iron and calcium. A child who gets enough of these minerals will absorb less lead.
Utilities and structure safety after a flood
Gas & Electric Safety
Once you return to a flood-affected home, make sure the gas and electric service is off. Then use your nose to check the house for any gas odor. Never smoke or use an open flame for light during this process. If you smell gas, clear out and notify the gas company fast. Tell them to check whether gas lines have been flooded. Most home gas systems operate at relatively low pressure, and flooding of any depth will back water into the gas lines. These lines must be purged and cleaned before they can be used again, and experts must handle these jobs. Also check for electrical hazards like damaged or wet wires and outlets, so that when the juice flows, you're not in for any more shocks.
Electrical safety precautions are a must when you re-enter buildings that have been flooded. First, make sure electrical service is turned off before going back into a building for the first time. Do that by turning off the main electrical switch and all circuits. Until you do, never come into contact with standing water: there could be some hot wires below the water line. Throw away submerged fuse boxes and all of their contents. Remove covers from all outlets and fuses or breaker boxes and flush them with clean water. Allow time for drying and then spray them with contact cleaner or lubricant. And don't turn the electricity back on until the whole system has been checked by a licensed electrician.
If you are without electricity, you may have turned to fuel-burning sources for heat, light and other needs. USE GREAT CAUTION. Fuel-burning devices in closed-in areas pose a great risk of carbon monoxide poisoning. Carbon monoxide has no odor and you can't see it, but it can kill you! Here are symptoms to watch out for. A mild headache that gets worse, shortness of breath and irritability. Poor judgment, memory loss and rapid fatigue are all signs of carbon monoxide poisoning. The symptoms can lead rapidly to coma and death. To treat carbon monoxide poisoning, immediately get everybody -- and your pets -- out of the building. Provide fresh air and call medical assistance at once.
Make sure ventilation is good whenever you use kerosene lamps, wood-stoves or fireplaces. NEVER use a gas oven or range to heat your house. NEVER burn charcoal in your house or garage to heat or cook. Provide plenty of ventilation when using a gas-powered pump for flooded basements or a gas-powered generator for electricity. Install and maintain carbon monoxide detectors.
For More Information
- Asbestos Hotline: 1-800-368-5888.
- Biological contaminants and carbon monoxide: Contact the Indoor Air Quality Hotline at 1-800-438-4318 or the Consumer Product Safety Commission at 1-800-638-2772.
- Floods: Order copies of the American Red Cross/FEMA's Repairing Your Flooded Home from the Federal Emergency Management Agency (FEMA), P.O. Box 2012, Jessup, MD 20794-2012, or call their publication warehouse at 1-800-480-2520; or call your local chapter of the American Red Cross and ask for publication number ARC 4477.
- Materials resistant to water damage: Order Flood-Proofing Regulation, a manual that lists materials for floors, walls, and ceilings that are resistant to water damage. U.S. Army Corps of Engineers, Attn: CECW-PF, 20 Massachusetts Avenue, NW, Washington DC 20314.
- Food: Contact the U.S. Department of Agriculture Food Safety Hotline 1-800-535-4555.
- Lead: Contact the National Lead Information Center at 1-800-424-5323.