Section 4

4.0 EVALUATION OF VULNERABILITY AND RECOMMENDED ACTIONS

4.1 Flooding

The flooding problem in Ouachita Parish can be attributed to the data presented in Section 2.1- Topography. That section explains how the Ouachita River and its tributaries drain about 15,000 square miles of land. All of this water converges in the Parish in an area with very low, flat topography creating ideal conditions for flooding. With such a large drainage basin, flooding is inevitable.

Solutions to these flooding problems can be classified into two categories: Structural projects and Non-Structural projects. One structural project is the installation of pump stations, which can help drain water from drainage basins. In the flood of 1982 in Ouachita Parish, many drainage basins could not drain into water bodies because the surface water elevation of those water bodies were too high. Floodgates were closed in order to prevent these water bodies from backing up into the drainage basins. This prevents backwater from entering drainage basins, but runoff exiting into the drainage basin cannot enter the water body. In this situation, large capacity pumps can move large volumes of water very fast in order to reduce the drainage burden on these basins. Also in situations where no flood gate is present, such as heavy rainfall, pumps can move water much faster from a gathering point than gravity in areas with low, flat terrain.

There are also structural projects that control water flow. Levees and sea walls like the ones that protect the cities of Monroe and West Monroe from the rising water of the Ouachita River can be extremely effective. They must be of adequate height and their integrity (cracks, cave-ins, etc.) must me monitored in order to remain effective. A sudden levee or sea wall break in a high water event can send a devastating wall of water on a community with little or no warning.

Drainage canals and spillways can add to the efficiency of naturally occurring drainage by speeding up runoff and counteracting man-made drainage barriers. Drainage canals like levees must also be maintained to remain effective. The canals must be kept clear of debris, which can form dams and increase flooding hazards.

There are also non-structural solutions to flooding problems. The most effective and cost efficient solution is to prevent structures from locating in flood prone areas. The local government can implement building codes in their community that would require building permits to be issued. Issuance of building permits for flood prone areas would be denied under an ordinance such as this. A citizen wishing to build in the community must first prove that the proposed location for their structure is not susceptible to flooding. For example, no building permits for inhabitable dwellings could be issued if the location is in the 100-year flood plain.

This measure prevents flooding destruction before it ever occurs and therefore is most effective. However, some community leaders who have constituents with property in a flood prone area may not like this idea for fear of the property losing its value if no building is allowed.

Removal (acquisition) of existing flood prone structures, is another non-structural option. This can prove to be cost efficient for structures that are considered repetitive flood losses by FEMA. Owners of these structures have been paid large sums of money in flood insurance claims over a period of years by FEMA. It may prove more cost effective for FEMA to purchase the structure and remove it to prevent further payouts of insurance claims on it rather than to continue to pay for flood damages. Some homeowners may not prefer this if they are emotionally attached to their home.

Protecting existing flood prone structures is effective as a non-structural project also. Small levees around a flood prone structure can keep back rising river waters or flash floods from heavy rain. However, as with larger levees, small levees can break or leak at a critical time or be of inadequate height to prevent flood damage to a structure. Elevating flood prone structures above the surface water elevation of past floods can also offer protection. This puts the structure out of harm provide a parking garage or storage space for the homeowner. Structures can only be elevated to limited extent. Placing the structure too high can make it unstable and cause it to lose its foundation if swift flood waters are moving below the home.

4.2 Tornado

Although the probability of a tornado touching down in Ouachita Parish is less than 1%, tornadoes are still examined in this section due to the severe damage they may impose when they do strike. In addition, an evaluation of tornadoes indicates that there is little that could be done to mitigate the disastrous effects of tornadoes on property. However, certain steps can be taken to protect lives and prevent injury.

Proper warning from weather officials can help reduce casualties and injuries. Local weather officials with the National Weather Service as well as local TV stations can use sophisticated equipment such as Doppler Radar to track development and movement of tornadic storm cells.

Storm shelters and safe rooms are also effective in preventing loss of life and injury. A storm shelter is a structure separate from a house that may be fully or partially buried and will have reinforced walls and roof. A safe room is a concrete and steel reinforced room built in a new or existing above ground structure that can provide great protection during storms. If someone is warned of an approaching tornado far enough in advance, they can seek shelter in a storm shelter of safe room where they will not be struck by flying debris.

4.3 Severe Weather

Lightning, high wind and hail are considered severe weather. Tornadoes and flooding were dealt with in Sections 4.2 and 4.1. Lightning, high wind and hail, like tornadoes, are difficult to predict. Properly grounding a house is the best protection against lightning. High wind is probably more common than tornadoes in Ouachita Parish. Most of the same mitigation steps used for tornadoes can be employed for high wind as well. Figure 4.1 shows the wind zones for Louisiana as categorized by FEMA.

4.4 Others

Technological Hazards

Technological hazards were considered to be facilities subject to EPA Risk Management Program (RMP) or required to under EPA Toxic Release Inventory (TRI) requirements.

RMP facilities are required to have an emergency response program of their own which includes employee training in response procedures in the event of a chemical release, fire or explosion. They are also required to design and maintain a safe facility, minimize the offsite consequences of accidental releases of extremely hazardous substances and to identify hazards that may result from such releases.

TRI facilities are required to report to regulatory agencies their total releases of chemicals specified by EPA. These facilities are also required to provide a list of their chemical inventory and Material Safety Data Sheets (MSDS) to the Local Emergency Planning Committee (LEPC), to their State Emergency Response Commission (SERC) and to their local fire department. This will ensure that the community as well as emergency officials are adequately informed of what hazards are posed by exposure to chemicals at the facility.

Ice Storms

Ouachita Parish has experienced 5 ice storms since 1994 with damages totaling 51 million dollars. Ice storms occur when temperatures fall below freezing near the surface, but temperatures at higher altitudes are warm enough to produce rain. When the rain reaches the surface, it freezes to whatever it strikes. Besides creating dangerous driving conditions, ice storms cause trees to break and fall on power lines. Residents living in remote parts of Ouachita may go days before power company crews are able to repair power lines servicing their homes. Power companies have developed extensive right-of-way maintenance programs to remove trees that pose a threat to falling on nearby power lines. Ice storm contingency plans have also been developed by power companies. These plans identify priority facilities such as hospitals that need power service restored and lists neighboring utility companies that if unaffected by the ice storm, can send service crews to the area to help restore power.

Table of Contents > Next
.
4.0 EVALUATION OF VULNERABILITY AND RECOMMENDED ACTIONS 4.1 Flooding The flooding problem in Ouachita Parish can be attributed to the data presented in Section 2.1- Topography. That section explains how the Ouachita River and its tributaries drain about 15,000 square miles of land. All of this water converges in the Parish in an area with very low, flat topography creating ideal conditions for flooding. With such a large drainage basin, flooding is inevitable. Solutions to these flooding problems can be classified into two categories: Structural projects and Non-Structural projects. One structural project is the installation of pump stations, which can help drain water from drainage basins. In the flood of 1982 in Ouachita Parish, many drainage basins could not drain into water bodies because the surface water elevation of those water bodies were too high. Floodgates were closed in order to prevent these water bodies from backing up into the drainage basins. This prevents backwater from entering drainage basins, but runoff exiting into the drainage basin cannot enter the water body. In this situation, large capacity pumps can move large volumes of water very fast in order to reduce the drainage burden on these basins. Also in situations where no flood gate is present, such as heavy rainfall, pumps can move water much faster from a gathering point than gravity in areas with low, flat terrain. There are also structural projects that control water flow. Levees and sea walls like the ones that protect the cities of Monroe and West Monroe from the rising water of the Ouachita River can be extremely effective. They must be of adequate height and their integrity (cracks, cave-ins, etc.) must me monitored in order to remain effective. A sudden levee or sea wall break in a high water event can send a devastating wall of water on a community with little or no warning. Drainage canals and spillways can add to the efficiency of naturally occurring drainage by speeding up runoff and counteracting man-made drainage barriers. Drainage canals like levees must also be maintained to remain effective. The canals must be kept clear of debris, which can form dams and increase flooding hazards. There are also non-structural solutions to flooding problems. The most effective and cost efficient solution is to prevent structures from locating in flood prone areas. The local government can implement building codes in their community that would require building permits to be issued. Issuance of building permits for flood prone areas would be denied under an ordinance such as this. A citizen wishing to build in the community must first prove that the proposed location for their structure is not susceptible to flooding. For example, no building permits for inhabitable dwellings could be issued if the location is in the 100-year flood plain. This measure prevents flooding destruction before it ever occurs and therefore is most effective. However, some community leaders who have constituents with property in a flood prone area may not like this idea for fear of the property losing its value if no building is allowed. Removal (acquisition) of existing flood prone structures, is another non-structural option. This can prove to be cost efficient for structures that are considered repetitive flood losses by FEMA. Owners of these structures have been paid large sums of money in flood insurance claims over a period of years by FEMA. It may prove more cost effective for FEMA to purchase the structure and remove it to prevent further payouts of insurance claims on it rather than to continue to pay for flood damages. Some homeowners may not prefer this if they are emotionally attached to their home. Protecting existing flood prone structures is effective as a non-structural project also. Small levees around a flood prone structure can keep back rising river waters or flash floods from heavy rain. However, as with larger levees, small levees can break or leak at a critical time or be of inadequate height to prevent flood damage to a structure. Elevating flood prone structures above the surface water elevation of past floods can also offer protection. This puts the structure out of harm provide a parking garage or storage space for the homeowner. Structures can only be elevated to limited extent. Placing the structure too high can make it unstable and cause it to lose its foundation if swift flood waters are moving below the home. 4.2 Tornado Although the probability of a tornado touching down in Ouachita Parish is less than 1%, tornadoes are still examined in this section due to the severe damage they may impose when they do strike. In addition, an evaluation of tornadoes indicates that there is little that could be done to mitigate the disastrous effects of tornadoes on property. However, certain steps can be taken to protect lives and prevent injury. Proper warning from weather officials can help reduce casualties and injuries. Local weather officials with the National Weather Service as well as local TV stations can use sophisticated equipment such as Doppler Radar to track development and movement of tornadic storm cells. Storm shelters and safe rooms are also effective in preventing loss of life and injury. A storm shelter is a structure separate from a house that may be fully or partially buried and will have reinforced walls and roof. A safe room is a concrete and steel reinforced room built in a new or existing above ground structure that can provide great protection during storms. If someone is warned of an approaching tornado far enough in advance, they can seek shelter in a storm shelter of safe room where they will not be struck by flying debris. 4.3 Severe Weather Lightning, high wind and hail are considered severe weather. Tornadoes and flooding were dealt with in Sections 4.2 and 4.1. Lightning, high wind and hail, like tornadoes, are difficult to predict. Properly grounding a house is the best protection against lightning. High wind is probably more common than tornadoes in Ouachita Parish. Most of the same mitigation steps used for tornadoes can be employed for high wind as well. Figure 4.1 shows the wind zones for Louisiana as categorized by FEMA. 4.4 Others Technological Hazards Technological hazards were considered to be facilities subject to EPA Risk Management Program (RMP) or required to under EPA Toxic Release Inventory (TRI) requirements. RMP facilities are required to have an emergency response program of their own which includes employee training in response procedures in the event of a chemical release, fire or explosion. They are also required to design and maintain a safe facility, minimize the offsite consequences of accidental releases of extremely hazardous substances and to identify hazards that may result from such releases. TRI facilities are required to report to regulatory agencies their total releases of chemicals specified by EPA. These facilities are also required to provide a list of their chemical inventory and Material Safety Data Sheets (MSDS) to the Local Emergency Planning Committee (LEPC), to their State Emergency Response Commission (SERC) and to their local fire department. This will ensure that the community as well as emergency officials are adequately informed of what hazards are posed by exposure to chemicals at the facility. Ice Storms Ouachita Parish has experienced 5 ice storms since 1994 with damages totaling 51 million dollars. Ice storms occur when temperatures fall below freezing near the surface, but temperatures at higher altitudes are warm enough to produce rain. When the rain reaches the surface, it freezes to whatever it strikes. Besides creating dangerous driving conditions, ice storms cause trees to break and fall on power lines. Residents living in remote parts of Ouachita may go days before power company crews are able to repair power lines servicing their homes. Power companies have developed extensive right-of-way maintenance programs to remove trees that pose a threat to falling on nearby power lines. Ice storm contingency plans have also been developed by power companies. These plans identify priority facilities such as hospitals that need power service restored and lists neighboring utility companies that if unaffected by the ice storm, can send service crews to the area to help restore power.
Table of Contents > Next