The base flood: Start with the base flood--a statistical concept that considers both the likelihood and severity of a flood. The base flood is also known as the often misunderstood 100-year flood or by the technical term, 1% chance flood. If you use the last two names, make sure the non-engineers in your planning effort understand them.

People may have heard the term 100-year-flood in relation to a recent flood and think they've seen the worst that nature can dish out, although the base flood is really a minimum standard for regulation. We like base flood because it forms the basis for your planning and does not imply that this is a rare event.

To begin, you should have a Flood Insurance Rate Map (FIRM), which shows your base floodplain as mapped by FEMA. It identifies the flood hazard area that your community must regulate under the NFIP and that lenders and insurance agents use in determining who must purchase flood insurance and how much a policy costs. In other words, the NFIP has already designated an area that your mitigation planning should address.

Other flooding: Use the FIRM's floodplain as a starting point, then consider flooding in drainage areas too small to be reflected on the FIRM as well as problems discovered since the FIRM was prepared. Many communities have experienced floods larger than the mapped base flood. Public involvement should identify these problem areas, and the planning committee should decide which ones to address. In most cases, it pays to include them all--don't ignore anyone's floods.

A lot of help is available from other agencies and organizations; ask them for maps, descriptions, and historical data on the hazards with which they are familiar. Along with the FIRM, your community received a Flood Insurance Study, which has additional historical and technical information.

This step should produce a written description and assessment of all the flood hazards facing the community, including the mapped base flood and larger historical floods. It may also include local drainage problems, sewer backup (if water is in someone's house, it's a flood to them), and even flood-related problems, such as erosion and subsidence. A map can be a very useful tool for summarizing and displaying the areas affected by different types of flooding.

Getting participants to agree on a problem statement is the first step in getting them to agree on goals and solutions. The problem description should include a map or series of maps of areas of concern, which can be updated as more information becomes available. The problem statement should also describe the impacts of flooding.

Buildings: The Community Rating System requires a count of the number of buildings affected by each type of hazard, e.g., overbank flooding, coastal storm surge, local drainage, sewer backup, erosion, etc. This count also informs planners and other interested parties of the magnitude of the problem.

The building count should reflect use and type of building, because hazards affect each type differently. For example, an historic site or local landmark may deserve more attention than other properties because of its special value to the community. The flooding of a commercial or industrial building is likely to be more costly than that of a house and to have a broader impact on the community if it has to close after a flood. On the other hand, many local officials feel that businesses can take care of themselves and owner-occupied housing deserves more attention.

Similarly, a flooded city hall will have a greater impact on the community than a flooded residence. A building with a basement will be hit harder by shallow flooding and sewer backup than one with a crawlspace. Whatever your priorities, time and resources dictate how much data can be collected. In most cases, aerial photos or a windshield survey will provide needed data (you may also be able to get help from the residents on your planning committee).

Another useful bit of information is an assessment of predicted or actual building damage. Again, other agencies can help. Average annual damage figures may be available from a study by the Corps of Engineers or the Natural Resources Conservation Service. Historical damage in the form of flood insurance claims is available from FEMA (but remember to adjust the numbers to reflect uninsured losses).

If time and resources permit, you may want to use computerized loss estimation modeling software to evaluate your flood problem. An example is the FEMA-funded HAZUS model. Originally designed to estimate losses from earthquakes, HAZUS will soon be available to estimate future losses from other hazards, including wind and flood. This software allows you to use local information on building stock and other factors to estimate losses that might occur in various size flood events, thereby providing good information for flood mitigation planning.

Repetitive losses: FEMA programs, especially the CRS, are particularly concerned about repetitive losses--two or more flood insurance claims for more than $1,000 for the same structure over a 10-year period. Such buildings represent fewer than 2% of the flood insurance policy base, but over 35% of claims payments.

If you are a community official, you can get a list of your community's repetitive losses from 1978 to the present from your FEMA regional office. (If your community currently participates in the CRS, it already has that information.). Many communities have found this information to be useful because it identifies previously unknown problem areas. Developing mitigation responses to repetitive loss problems may also help your community compete for FEMA funds.

Other properties: Floods impact more than buildings. The problem assessment should also review the following items:

• Critical facilities, such as emergency operations centers, communications facilities, hospitals, and schools that may be damaged or isolated
• Roads, bridges, and transportation facilities that may be damaged or closed
• Other infrastructure, such as water and sewage treatment plants, that could become inoperable due to a flood
• Protection measures in effect or under construction
• Impacts of past disasters
• Undeveloped areas and wetlands that provide natural and beneficial functions

Other concerns: A plan needs to discuss other community concerns besides protection from flooding. During this phase of the planning process, invite people with other interests, such as recreation, water quality, economic development, and historic preservation, to be involved. Some of them may have already prepared plans or written problem statements.

Future directions: Finally, your problem definition should review expected changes to your community and its watershed, particularly the potential for vacant land to be developed. Note the trends for redevelopment in any of the flood-prone areas and possible constraints, such as a land-use plan, zoning, or ownership.

Take a look at the watershed. Is there a lot of land subject to a lot of development? If so, the runoff into your community will likely increase, and, if not managed, the frequency and height of flooding will increase as well. Are natural storage areas going to be developed? Will other areas of natural or cultural importance be lost?

There is a choice at this step. You can limit your work to reacting to your flood problem and identifying flood mitigation goals, such as Protect lives during a hurricane, Reduce the potential for flood damage to existing buildings, and Prevent construction of any more buildings in the floodway. Such goals are appropriate and in line with the minimum credit criteria for the CRS.

Your second choice is to look at how the floodplain and watershed affect your community. Many planners now promote a vision step in the planning process in which people review how they'd like their community to look in the future. What should your floodplain look like 20, 50, or 100 years from now? Is your vision of the floodplain limited to how well buildings are protected, or should you discuss the best use of this sensitive area?

Is your vision simply of an area free from water damage, or can you take advantage of the attention currently being given to flooding, coordinate it with other goals, and outline a way to develop a better community--not just a flood resistant one? If so, you may have some additional goals or vision statements, such as Have a river clean enough for swimming and fishing, Preserve all wetlands and natural storage areas in the watershed, Have a waterfront that attracts people, and Eliminate all substandard housing in the area.

Consensus: It is often easy to reach agreement on overall goals, but it is not unusual to take a long time to reach consensus on specific objectives related to particular areas or individual properties. However, doing so is time well spent and vital to gaining cooperation from all affected parties.

Make goals positive statements, something people can work for, not negative statements about the community. Where possible, settle on goals that support more than one interest, e.g., Implement erosion reduction measures to sustain farmland, improve water quality, and reduce sedimentation in stream channels.

Strive for unanimous support, or at least agreement that no one will oppose a goal or objective statement. Short of that, you or your committee chair will have to decide if decisions are made using the method of last resort--majority vote.

The CRS encourages a review of six general mitigation strategies. These are listed in the box on page 10, along with example measures, and can be used as a checklist. Don't eliminate anything until each item has been given careful consideration. While some measures may be quickly eliminated, most should be evaluated to determine how they work as well as their costs and benefits. During this planning step, walk your planning committee through a systematic review of each measure. Determine whether and how a measure is currently being implemented and then review appropriate changes. Discard a measure only after the following questions are answered negatively:

• Is the measure technically appropriate for the hazard?
• Does it support any of the goals and objectives?
• Do its benefits equal or exceed its cost?
• Is it affordable?
• Will it comply with all local, state, and federal regulations?
• Is it fair to all concerned?

Also consider whether a project will have a beneficial or neutral impact on the environment and how the floodplain will look when it's completed.

Questions about technical aspects or agency programs should be directed to experts from the agencies or organizations with whom you coordinate (see Step 3). Depending on your situation, you may want to formalize your process of selecting recommended measures and document how you decided to include or not include some activities, especially if they're controversial.

Funding: Many of the measures will require additional expenditures. This is another instance in which other agencies and organizations can be of great assistance. There are literally hundreds of public and private programs that can help fund worthy projects. They usually have several prerequisites, such as a written plan, a budget, and an explanation of benefits.

Some projects can be funded by several different parties, each of which is interested in one or more objectives. Often, agencies and organizations can fund only part of a project, and they usually favor those projects that have other sources of funding. In other words, they prefer to support multiobjective projects, and this is where coordination with other community goals and objectives can pay off.

Don't forget local sources of funding. Businesses and organizations will frequently support projects that benefit their customers, employees, or members, or that provide a public relations benefit. Many projects, such as an acquisition project that creates more parking space for businesses, provide direct benefits to local groups.

Finally, don't forget in-kind services, which can be an excellent alternative to cash. Instead of paying for park maintenance, why not have a service organization maintain the area with volunteers? Often, in-kind services can be counted toward the local share needed to match other funding.

Balanced program: One of the greatest benefits of the 10-step planning approach is that it promotes balance in tackling flooding and other community problems. It should not be considered an excuse to justify someone's favorite project above all others, such as a large levee, nor should it emphasize one option, because you will likely wait years for such a solution. The odds are good that a flood will occur before such a big project is completed.

Although most attention is usually focused on reducing losses to existing development, dealing with future development and preserving natural areas pays off in the long run and prevents small problems from becoming bigger ones. A balanced program with measures from each of the six mitigation strategies will help to protect existing development, manage new development, and protect natural and beneficial floodplain functions. Also, the CRS provides more points if more than one or two of the six mitigation strategies are recommended.

To encourage more balanced programs, FEMA is transforming the historical postdisaster emphasis in state mitigation planning into a more holistic approach that looks at both predisaster and postdisaster activities and emphasizes a state and local cooperative approach.

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