We have discussed how proper land-use management of wetlands, the 100-foot buffer zone, and the 1,000-foot critical areas designation, can improve the way the land handles water flows and the beneficial effects that can have for residents as well as nature. That said, the bay region and mid-Atlantic coast is subject to powerful storms up to and including hurricanes, so flooding is a risk to be considered. Here we’ll take a look at:
- Flood Damage Risks
- Development Issues and Restrictions
- Buy-Back Efforts
Flood Damage Risks
In August 2005 the Maryland Department of the Environment (MDE) and the Eastern Shore Regional GIS Cooperative (ESRGC) at Maryland’s Salisbury University released a report assessing the State’s vulnerability to flood damage. The threat of riverine and coastal flooding was assessed for each county and the City of Baltimore with new hazard modeling software. The software enabled analysts to perform “what-if” scenarios on flood damage, such as what if a flood wall or levee were built, or a floodplain filled.
According to MDE the modeling showed that “13.4% of the State’s area is within a 100-year floodplain… An estimated 44,755 buildings throughout the State would be damaged by a 100-year flood, with $8.12 billion in direct economic losses.” And 86% of the total damages stemmed from residential buildings. ”Somerset, Dorchester, St. Mary’s, and Calvert Counties were vulnerable to the largest percent of substantially damaged buildings. The data generated by the software compares reasonably well with data that had been complied by other methods,” according to the report.
Development Issues and Restrictions
The final version of the “Maryland Model Floodplain Management Ordinance” was issued in September 2010. All Maryland counties and 92 municipalities participate in the National Flood Insurance Program (NFIP). In return for these jurisdictions managing development within the 100-year floodplain in order to minimize future flood damage, residents can buy coverage via the NFIP. MDE said the state’s model ordinance has been widely adopted.
So all development within the floodplain, including activities such as grading, filling, dredging, extraction, storage, subdivision of land, and the construction or improvement of structures, requires a permit. Proposed development must not increase flooding or create a dangerous situation during flooding, especially on another person’s property. If a structure is part of the development plan, it must be constructed to minimize damage during flooding. Here are some of the general requirements.
Avoidance and Minimization: The Model Ordinance stresses that local officials must work with permit applicants to avoid development within the floodplain wherever possible. If unavoidable, the effects of development must be minimized. Proposed development may not increase flooding or create a dangerous situation during flooding, especially on another person’s property. If a structure is involved, it must be constructed to minimize damage during flooding.
Flood Protection Setback: Flood damage may be minimized by requiring development to be set back 100 feet from the top of the banks of all FEMA-mapped water courses and 50 feet from unmapped streams. Building within the setback zone should not be allowed. Certain exemptions may be allowed and local officials may consider variances.
Elevation of Structures: Damage to new and substantially improved floodplain structures is minimized by elevating the lowest occupied floor one foot above the 100-year flood level. This requirement applies to all electrical devices, including heat pumps, furnaces, air conditioners, hot water heaters; plumbing devices such as toilets, sinks, tubs, showers; and gas appliances. Minor additions in nontidal floodplains must also be elevated. Enclosed areas below this level are strictly limited in their use, such as storage, crawl spaces, and parking.
Water Equalizing Vents: Enclosed areas below the level of the 100-year flood must be vented to allow water to move freely in order to equalize pressure on both sides of the wall. One square inch of vent opening is required for every square foot of area enclosed below flood level.
Coastal and High Hazard Areas: Where high wind and wave action creates an additional hazard, residences and other structures must be elevated with pilings or columns above the 100-year floodplain. That requires the lowest horizontal support structures for the bottom floor are above flood levels and the area underneath should remain open to permit the free flow of water. Another option is to use breakaway materials to enclose the lower level so that storm of flood water will not damage the structure’s supports.
Buy-Back Efforts
The Comprehensive Flood Management Grant Program (CFMGP) created in 1976 funded studies, planning, and capital projects to improve watershed management and mitigate flooding damage. CFMPG, also known as the “Flood Hazard Mitigation Act of 1976″ provided for grants immediately after floods for acquisition of flood-damaged owner-occupied dwellings. Elevations and relocations of homes are also eligible for funding. Acquired land is permanently converted to open space.
In recent years, according to MDE, the CFMPG has been used primarily to fund half of the non-federal share of the FEMA Hazard Mitigation Grant Program. In general terms, the FEMA grant program funds 75 percent of flood mitigation projects, local governments fund 12.5 percent, and CFMPG funds 12.5 percent. CFMPG has been involved in the acquisition of more than 400 flood prone properties, usually with shared funding from local and federal agencies.
Information presented in this article is believed to be accurate. However, legislation and enforcement are subject to change and interpretation. It is recommended that you contact your local government land use department in order to discern how regulations are enforced in your area. This information is presented without warranty.
