Protect Your Property from Flooding
Importance of Maintaining the Drainage System
When it rains, street drains help to keep neighborhoods from flooding. When leaves collect in gutters and block these drains, water can back up and cause ponding that slows or stops traffic and can even flood yards and homes. While autumn is when leaves are most likely to collect in drains, it can happen at any time of the year. City crews work hard to maintain all of the City’s drainage infrastructure, including storm drains on streets. However, we need your help too. You can help prevent flooding by paying attention to what’s happening with the drains on your block. A few small maintenance actions on your property can also prevent stormwater from ponding:
- Keep leaves and debris out of drains.
- Avoid piling yard waste like fallen leaves and sticks in your yard, where it could wash into City drains. Keep it in a yard waste bin or other container.
- Use a rake or broom to remove leaves and debris from the tops of storm drains, and then place the material in your yard waste cart.
- Maintain your gutters and downspouts.
- Clean the gutters and drainage downspouts attached to your roof twice a year. Just one wind or rainstorm can clog a well-flowing drainage system.
- Inspect for leaks or damage to rain gutters that could cause a flat roof to flood.
- Direct flows from downspouts away from your foundation, without discharging flows to adjacent properties.
- Never discharge water over the edge of a steep hill.
- Maintain your drainage systems. Maintaining the drainage system on private property is the owner’s responsibility.
- Check your property’s drainage system. This is especially important on commercial properties that have catch basins or other drainage systems. Maintaining these systems is the property owner’s responsibility. The best way to find out what’s in your pipes is to ask a professional to "video inspect" your underground drainage system.
- If you have a driveway that leads down from the street, be sure to clear the drain at the bottom of the slope.
- If you live at the base of a hill or on a cliff, ensure that drainage and retaining walls are properly functioning.
Respect the City’s Drainage System
- Don’t put grass clippings, leaves or other debris into any drains, ditches, creeks, culverts, gutters, or ravines in the City.
- Do not store furniture or other items like firewood, fuel tanks, containers and loose items in your yard, as floodwaters can wash these items into culverts and cause flooding.
- It is against the law to dump or to allow any material to enter the drainage system, as it leads to blockages.
- To report illegal dumping into the City’s stormwater system, call Jay Beeson in the Public Works Department at 843-280-5588.
Protect Your Property from Wind/Hurricane Damage
Nonstructural Protective Measures: To protect against wind damage without making any structural changes to a building, you can:
- Identify and remove trees and branches that could fall on the building walls or roof, or on power lines
- Identify and repair loose or damaged building components such as siding, soffits and fascia, shingles and roofing, brickwork and brick chimneys.
A hurricane brings torrential rain, and severe rainstorms may accompany a tornado. Buildings damaged by wind often suffer water damage as well. Water driven by hurricane-force wind can enter through usually rain-tight openings, and rain entering through a damaged roof can lay waste to the inside of a building. Make sure that items such as important documents and irreplaceable personal objects such as photographs are stored in a safe location, preferably in watertight containers. Consider putting extra cash and important papers in a safe deposit box at your bank.
Hurricane warnings are issued about 24 hours before the hurricane is predicted to hit your area. If your area is under a hurricane warning:
- Move breakable items away from doors and windows
- Board up doors and windows
- Bring in outdoor furniture and other personal property kept outdoors
- Secure manufactured home anchors
- Secure outbuildings
- Secure or move boats
- Turn off propane tanks
Structural Protective Measures: The roof, doors, and windows of your house or place of business are potentially vulnerable to wind damage. When houses are exposed to hurricane forces, roofs are most susceptible to damage, followed by walls and openings.
Roofs can be protected from wind damage by:
- Ensuring that plywood roof sheathing is properly installed
- Bracing roof trusses
- Installing hurricane straps
You can strengthen doors and windows by:
- Installing reinforcing bolt kits at the top and bottom of doors
- Reinforcing garage doors
- Installing storm shutters over windows
Protecting Your Place of Business: When a place of business is damaged, the business owner faces the cost to repair or replace the building(s). In addition, the business can suffer loss of inventory, business interruption, and loss of wages for employees. Structural measures recommended to protect your place of business from wind damage are the following:
- Use threaded fasteners to attach metal roof decking. Welds are often unable to carry uplift loads
- In tornado-prone areas, use enhanced wind design for roof coverings on essential buildings
- Use adequate ties to foundations and roofs when reinforcing concrete and partially reinforced masonry
- Make ties between concrete and other materials with drilled-in fasteners or cast-in-place fasteners
- Engineer and construct masonry walls to support the specific architecture of the building (i.e., exterior wall panels, parapets, and decorative finishes). Diaphragm action to resist wind-generated shear forces must be maintained and reinforcement must be properly placed in concrete and masonry walls to reduce the possibility of collapse during high wind storms
- Use anchors in precast concrete buildings to prevent the uplift of hollow core planks and other precast elements during high winds
- Avoid the use of powder-driven anchors to attach bottom plates of walls to concrete unless the anchors are very closely spaced to resist pull-out
- Minimize the creation of wind-borne debris by appropriately designing, manufacturing, and installing architectural features
Permanently Retrofit a Building
Retrofitting means making changes to an existing building to protect it from flooding or other hazards such as high winds and earthquakes. FEMA’s Homeowner’s Guide to Retrofitting: Six Ways To Protect Your Home From Flooding, provides detailed information that will help you decide whether your house is a candidate for retrofitting. The guide helps by describing six retrofitting methods that protect your house from flooding:
- Elevation is raising your home so that the lowest floor is above the flood level. This is the most common way to avoid flood damage.
- Wet floodproofing makes uninhabited parts of your home resistant to flood damage when water is allowed to enter during flooding.
- Relocation means moving your home to higher ground where the exposure to flooding is eliminated altogether.
- Dry floodproofing is sealing your home to prevent flood waters from entering.
- Levee and floodwall protection means constructing barriers to prevent flood waters from entering your home.
- Demolition means razing your home and rebuilding properly on the same property or buying a home elsewhere.
Emergency Floodproofing Measures
Emergency measures are temporary measures that are implemented between the flood warning and the flood event to protect the building from floodwaters. Sandbags, temporary flood barriers, and flood wrapping systems are common emergency flood protection measures.
- Sandbags: Temporary walls constructed of sandbags can be used to protect structures from flooding or provide additional height to existing levee systems when floodwaters reach critical levels. Typical sandbags are constructed of plastic or treated burlap bags approximately 14 inches wide and 24 inches long and are filled with sand or other fine-grained soils. Because of the intensive effort and amount of time required to provide protection even from relatively shallow water, sandbag walls are not a reliable protection measure. To be effective, sandbags and sand should be stockpiled and checked regularly to ensure that the sandbags have not deteriorated. Sand and/or filled sandbags stored unprotected out of doors in cold weather climates may freeze and be rendered unusable. The disadvantages of sandbags are high disposal costs and a tendency to absorb pollutants from contaminated floodwaters, which necessitates their disposal as hazardous waste.
- Temporary Flood Barriers: A number of vendors make temporary flood barriers that can be assembled relatively easily, moved into place, anchored, and filled with water or sand. The barriers must be sized for the site, and training and annual drills are important so personnel know how to deploy the barriers. Proper storage, including cleaning after deployment, is necessary to protect the materials over long periods. In 2006, FM Approvals published FM Standard 2510, Approval Standard for Flood Abatement Equipment (FM Approvals 2006). The current FM Approvals test protocols are for self-supporting, temporary barriers designed to protect against riverine flood depths up to 3 feet. These barriers are not tested for coastal flooding applications, where the presence of saltwater may hinder their performance. Because saltwater is denser than freshwater, a barrier filled with freshwater in a coastal location may float instead of providing protection against flooding.
- Flood Wrapping Systems: Flood wrapping systems are temporary emergency measures consisting of plastic or other synthetic waterproof sheeting material that is used to seal a building to prevent water intrusion during the flood duration. Wrapping systems present different challenges from impervious wall systems: They need to be anchored, stored, and repaired. Flood wraps benefit from barrier reinforcement such as sandbags or plywood walls and should generally be able to withstand the pressure of 3 feet of water for a limited period. Wrapping systems rely on the existing walls, which may need to be strengthened to resist flood loads, but they also need to bridge openings such as doors and windows, which typically require some type of temporary reinforcement to support the portion of the wrapping system that spans the openings. The area of openings and the flood protection level should be considered when selecting the wrapping material. When using flood wrapping material, refer to the manufacturer’s specifications for depth of flooding limitations, reinforcement requirements, and applicability with existing construction materials at the openings.