Return to Table of Contents

J. Hampton Beach Flooding and Storm Damage

 

Increased development and urbanization of the Hampton Beach area and the Coastal Watershed has depleted the amount of land and vegetation available to absorb precipitation and thus has increased the amount and rate of storm runoff. Impervious pavement for parking areas and additional roads, building roofs, compacted soil and infiltration of runoff into community storm sewer systems have together increased the amount and rate of peak stormwater discharge, thereby augmenting the flooding conditions both in Hampton and the Hampton Beach area. The impact of this increased runoff into the Hampton-Seabrook Estuary and the Taylor and Hampton Rivers when combined with ocean storms and potential sea level rise due to climate change make the Hampton Beach area highly vulnerable to destructive flooding and storm damage.

 

Flooded Houses, White Rocks Island, 1920s. Courtesy Alzena Elliot

History of Flooding and Storm Damage in the Hampton Beach Area

The history of flooding and destructive storms in Hampton Beach dates back to 1723. Since that time, the state and Hampton have experienced approximately 50 major floods. Flooding can occur at any time during the course of the year. Normally, a single intense heavy rainfall would cause minor to moderate flooding. The most severe flooding usually occurs when there is more than one event—such as when two storms occur during a seven-day period or when coastal surge/heavy wind and rain occur simultaneously. A recent example of such an event was Hurricane Floyd in mid-September 1999. The types of natural storm events in Hampton that could lead to flooding and storm damage include hurricanes, northeasters, heavy rain and snowstorms, snow-pack melt, blizzard, or ice storms. The following table summarizes significant flooding events in the Town of Hampton over the last 30-year period with emphasis on the Beach area.

Table 18. Recent Significant Flooding Events in the Hampton Area Since 1968

Date	Type of Storm	Comments
March 1968	Heavy rain/snowmelt	Caused river flooding
Winter, 1972	Winter northeaster	Hampton Beach seriously damaged; federal disaster declaration.
April 1973	Heavy rain	5-7 inches in 36 hours plus high tide; extensive flooding in Hampton Beach
February 1978	Blizzard	Coastal surge plus high tide; extensive public and private damage in Hampton Beach
September 1985	Hurricane Gloria	Moderate to extensive flooding
August 1991	Hurricane Bob	Moderate to extensive flooding
October 1991	No Name Storm	Convergence of two storms; heavy wind and rain; extensive damage to Hampton Beach
October 1996	Heavy rain	Up to 18 inches in 36 hours; Hampton Beach experienced moderate flooding
June 1998	Heavy rain	Flooding conditions from rain over 7-day period

Source: Hampton Flood Hazard Mitigation Draft, 2000

 

Flood Mitigation Activities

The early development of Hampton Beach consisted of farmhouses, a few boarding houses, small hotels, and a few summer cottages. With the introduction of rail and trolley service and the 99-year lease by the Hampton Beach Improvement Company in the late 1880s, lands comprised of sand dunes located between present day Ashworth Avenue and Ocean Boulevard, experienced rapid development including construction of roads and parking lots. The sand dunes that acted as a barrier to ocean storm surge and provided open space were destroyed. In the early part of the 20^th century, the Town provided the State with beach land to construct seawalls or breakwaters to protect the private development of the Hampton Beach area. Since that time, there have been a number of structural improvements designed to prevent or mitigate flooding in the Beach area (see Table 19). The Town, the State, and the US Army Corps of Engineers funded these improvements.

Table 19. Chronology - Flood Mitigation Projects

Year	Activity	Comments
1900s	Breakwater construction	Construction to the Casino
1913	Extension of Breakwater	Construction to 150 ft south of Casino
1915	Three breakwaters under construction	Wall 22 ft above high water mark
1955	Construction main seawall – 3,300 ft combined with ACOE beach restoration	Steel and concrete structure from end of Main Beach to Boar’s Head and then steel sheet pile at North Beach; 6,450 feet of beach restoration
1965	ACOE – Hampton Harbor project	0.7 mile long channel at entrance to harbor
1973	ACOE – Beach restoration	Repair damage from 1972 winter storm
1988	Seawall replacement	$5.2 million state project to replace North Beach steel seawall

Sources: Town of Hampton, Flood Mitigation Plan, June, 2000.

Hampton Beach Report, prepared by Warren Manning, December, 1931.

 

Flood Mitigation

The Town of Hampton recently completed a Flood Mitigation Plan. It identifies areas that are prone to flooding, and proposes a list of strategies and specific projects that can be undertaken to mitigate against loss associated with future flood events. Additional information regarding flooding and mitigation can be found in the Flood Mitigation Plan: Town of Hampton, June 2000.

This Plan mentions that runoff needs to be retained and treated before it is discharged. However, no stormwater treatment facilities or detention basins have been identified in the Hampton Beach area. Furthermore, current town land-use ordinances do not require that post-development runoff be detained and treated before it is discharge. State law, however, requires this treatment if over 100,000 square feet is disturbed.

The Flood Mitigation Plan proposed ten flood mitigation project areas near Hampton Beach, most of them adjacent to tidal wetlands. Several projects proposed new tide gates, drainage facilities, redesign of road drainage, and culvert replacement. Regardless of which methods are chosen, the amount of mitigation identified in these areas provides a good understanding of the need for improving the impacts of flooding and the level of development that has occurred in and near the tidal areas.

 

Regulatory Approach to Flood Hazard Mitigation

FEMA Program

The Town of Hampton is protected by the flood insurance program of the Federal Emergency Management Agency (FEMA). This program, administered in New Hampshire through the NH Office of Emergency Management (OEM), allows individuals and businesses residing in communities that participate in the National Flood Insurance Program (NFIP) to obtain flood hazard insurance at subsidized rates. The program is aimed at reducing risk to life and property and enhancing flood storage capacity of a given area. The NFIP regulations require development to meet strict federal building codes while discouraging unsound development in flood hazard areas.

In 1986, the Town adopted a model flood insurance development ordinance that has allowed it to continue participation in this program. As part of the program, FEMA produced an updated Flood Insurance Rate Map (FIRM) that indicates the extent of flooding during a 100-year frequency flood (see Figure 26). Another way to describe the 100-year flood is to state that it is a flood with a 1 percent chance of occurrence in one year. The National Flood Insurance Administration uses the FIRM as a tool to identify the level of risk associated with specific properties located in the flood hazard area. The map is divided into various zones based on the vulnerability of a given area to flooding and storm surge. The most susceptible areas are in the V-Zone (subject to flooding and wave action) and the A-Zone (subject to significant flooding). Table 20 provides a brief description of the revised zones.

 

Figure 26. Floodplain Zones in the Hampton Beach Project Area

Source: Town of Hampton Zoning Ordinance, 1999.

 

In Hampton Beach, many properties are in the most flood prone zones. Table 21 identifies the number of lots, structures, and total square footage in each of the zones as well as totals for the Beach area. Over 60% of the lots and structures are within the AO and AE zones while less than 1% are in the VE zone, the most hazardous. The remaining properties are in the X zones, which are subject to minimal or moderate flooding.

 

Local Regulations

At present, Hampton has complied with the FEMA requirements for flood hazard areas by adopting minimum standards through a Special Flood Hazard Area zoning overlay in 1987 and amended in 1994. The Flood Mitigation Plan of June 2000 reviewed this section of the Town’s ordinances and suggested amendments. There were a range of suggestions including additions to the Definition Section such as "Structure" and "Substantial Improvement", review of allowed uses, additions to the General Requirement Section and stricter guidelines for the Building Inspector.

 

 

Table 20. Flood Zone Descriptions

Zone	Description
AE	Areas subject to inundation by a 100-year flood as determined by detailed methods. Base flood elevations are shown within these zones.
AO	Areas subject to inundation by 100-year shallow flooding (usually sheet flow on sloping terrain) where average depths are between one and three feet. Average flood depths derived from detailed hydraulic analyses are shown within this zone.
VE	Coastal area subject to inundation by a 100-year flood having additional hazards due to storm-induced velocity wave action. Base flood elevations derived from detailed hydraulic analyses are shown within these zones.
X	Areas of moderate or minimal hazard from the principal source of flooding in the area as identified in the community FIS. Buildings in these zones, however, could be flooded by severe, concentrated rainfall where local drainage systems are not normally considered in the community’s FIS. The failure of a local drainage system creates areas of high flood risk within zone X. Flood insurance is available in participating communities but is not required by regulation.
X500	Areas of moderate or minimal hazard from the principal source of flooding in the area as identified in the community FIS.

Source: FEMA, Technical Mapping Advisory Council, 1999.

 

Table 21. Hampton Lots and Buildings in Flood Zones

	Buildings			Lots
Zone	Structure Size (sf)	Structures	% of Total	Number	% Total	Area (acres)
Zone AE	2,347,020	2,285	56.9	1,519	56.2	1,311
Zone AO	294,593	260	6.5	180	6.7	25
Zone VE	5,632	5	0.1	16	0.6	175
Zone X	1,724,845	1,277	31.8	872	32.3	1,052
Zone X500	233,430	188	4.7	116	4.3	14
Totals	4,605,520	4,015	100	2,703	100	2,577

 

There are numerous structures in the Beach area which pre-date current flood hazard regulations. Any new structures would have to be constructed in accordance with state flood hazard requirements. New or substantially improved non-residential buildings must either have the lowest floor elevated to or above the base flood elevation if it is in the V-zone or be flood-proofed below the base flood elevation with solid walls if it is in the A-zone. The walls would have to be impermeable to the passage of water with structural components having the capability of resisting hydrostatic and hydrodynamic loads and effects of buoyancy.

 

Flood Hazard Planning May Lead to Federal Monetary Assistance

In recent years, the Town has taken a more proactive approach to mitigating flooding and storm damage. It has prepared a flood mitigation plan and developed an Emergency Management Plan and applied for federal mitigation assistance for two flood prone areas in the Hampton Beach area. The Hampton Conservation Commission has requested conservation easements adjacent to and within floodplains as part of development projects.

To better plan for flooding events and to minimize losses from flooding, the Town of Hampton contracted with the Rockingham Planning Commission to prepare the Town of Hampton Flood Mitigation Plan. The Plan provides an analysis of flooding conditions in the Town of Hampton and includes both structural and non-structural flood hazard analysis. This Plan is a pre-requisite to future federal disaster assistance. Many of the issues and recommendations apply to the Hampton Beach area.

One of the more significant findings of the study was the amount of loss the Town has sustained from floods over the past 20 years. FEMA tracks claims that have been made through the NFIP. Rockingham County has 1,959 policies with a record of over $5M paid out since 1978. In Hampton alone, there are 935 NFIP policies, almost half of the county as a whole. More striking is the amount paid out in claims over the same period—over $2.6M or over 50% of the claims in the county. Most of these claims come from the Hampton Beach area.

In addition, FEMA monitors the properties that have been subject to continued flooding insurance claims. In an effort to track properties that have sustained repetitive losses from flooding, the Town has requested a full accounting from FEMA. Although not a full record, the Town received a list of 16 repetitive loss properties, many of which are in the study area in the following locations: Concord Avenue, Plaice Cove, and the area south of Hampton River. As part of the flood hazard mitigation process, each of these property owners was contacted to determine their interest in participating in a flood hazard mitigation project for their property to minimize personal and economic costs associated with flooding events.

 

Flood Hazard Mitigation Recommendations

Hampton’s Flood Mitigation Plan identified a number of recommendations that would be necessary to mitigate damage from flooding. These actions included policy and regulatory activities as well as specific projects. Many of these would directly affect the Hampton Beach area. The Flood Mitigation Plan, accepted by FEMA, will provide the Town with a pathway to apply for and receive federal mitigation implementation assistance.

The Plan has identified the following non-structural flood hazard mitigation activities:

• A pilot program to provide incentives to owners of residential and commercial properties
• Enhancements to the Town’s Floodplain Management regulations;
• A conservation program to acquire land for flood storage purposes and prime undeveloped land in the flood hazard or floodplain area
• A grant or loan program for residential flood proofing
• Public information and education programs regarding building in the flood hazard and floodplain areas
• Apply for designation as a FEMA Project Impact Community (PIC) which encourages a community to incorporate the multi-hazard planning process into its ongoing comprehensive planning process
• Participation in the National Flood Insurance Program’s (NFIP) Community Rating System (CRS)

As a PIC community that participates in the CRS, the Town may achieve lower flood insurance rates for property owners if it undertakes flood mitigation projects that are approved by FEMA in the Flood Mitigation Plan. The Plan also identified the following proposed flood mitigation projects in the Hampton Beach Study area (see Table 22).

In addition to the above, the Plan identifies the following projects as High Priority projects: Little River area, Railroad track (Marelli Square), Kershaw/Moore, Police Department (Brown Avenue), and the Plaice Cove area.

 

Recent Activities and Conditions

During the past few years, Hampton has taken more proactive management actions for its floodplain areas. A number of activities have recently taken place or are currently underway. Aside from the actions in Flood Mitigation Plan High Priority Flood Mitigation Projects, many of these directly affect the Hampton Beach study area.

Meadow Pond Flooding/Eel Creek Restoration

The Town replaced the culvert in Eel Creek under Winnacunnet Road with a larger culvert a few years ago to alleviate the flooding caused by Meadow Pond. This action restored tidal marsh in the area that had been invaded by purple loosestrife and has assisted with the flow of water from Meadow Pond into the Hampton River and eventually into the Atlantic Ocean. There is still some concern about the impact of tidal flow on adjacent properties. The Town and the Rockingham County Natural Resource and Conservation Service (NRCS) are undertaking further study of this area to determine if any other actions need to be taken.

The Town of Hampton has begun to implement a number of the recommended activities in the Flood Mitigation Plan. These include the following:

Table 22. Very High and High Priority Proposed Flood Mitigation Projects

Very High Priority Flood Mitigation Projects

Name /Location	Hazard	Risk	Activities Recommended
Meadow Pond; Gill Street/ Redman Lane area	Tidal flooding; storm overflow	High tide >9.5’; Poor drainage design	Engineering assessment; elevation; improved drainage system
Kings Highway; East of Meadow Pond	Flooding; tidal events	Poor drainage; lack of culvert maintenance	Re-design Kings Highway; tide gates; review with Meadow Pond

 

High Priority Flood Mitigation Projects

Name /Location	Hazard	Risk	Activities Recommended
Brown Avenue area	Drastic flooding; tidal events; poor functioning tide gate/back valves, Culvert backup	Poor drainage, drainage patterns blocked with newer development; lack of maintenance of tide gates and catch basins	Replace culvert; add self-regulating tide gate. engineering assessment; elevation improved drainage system improved, raise structures; maintain tide gates, culverts, and catch basins
Police and Fire Stations	Flooding from storm and tidal events	Poor drainage, buildings flooded causing damage; public safety concerns.	Engineering assessment, possible new structures to FEMA standards
Lower end of High Street; from Mill Pond Lane to Kings Highway	Flooding, tidal events, dam washes away	Poor drainage, Meadow Pond floods culverts back up	Engineering assessment, design better drainage—culverts, etc.; reduce risk to residential properties—flood proofing, structure elevation
Island Path/Glade Path	Tidal flooding	Poor road construction	Re-deign and raise road
Great Boar’s Head	Rain/tidal events	Poor drainage; coastal surge overtops seawall	Engineering assessment; elevate structures; flood proofing
Ocean Boulevard north of harbor to the Seashell, the "Island Area"	Rain/tidal events; storm surge	Poor drainage; catch basins lower than high tide; storm surge into structure	Engineering assessment; flood proofing; re-vegetation
Hampton Harbor and north of bridge to Casino east of Ocean Boulevard	High tides and large rain/storm events	Poor building construction; flood from spillover; storm overtop; poor drainage	Engineering assessment; flood proofing; elevate structures; re-vegetation, purchase of development rights

Source: Town of Hampton Flood Mitigation Plan, June 2000.

Project Impact Community Designation

The Town applied for and received designation as a FEMA Project Impact Community. This designation will provide it with incentives to incorporate the multi-hazard planning process into its ongoing comprehensive planning process and allow the Town to participate in the NFIP Community Rating System.

Mitigation Projects

The Town is implementing recommendations from the Flood Mitigation Plan. They are applying for federal mitigation assistance for two high priority projects, the Island Area north of the Harbor to the Seashell Stage, and Plaice Cove. Both of them include a number of repetitive property losses. The Town is also undertaking a Stormwater Management Plan for the Brown Avenue area that includes both the Police and Fire Stations.

Sea Level Rise

NH DES is currently assessing the impacts of sea level rise on the coast due to global climate changes. Recent analyses have shown that storms are expected to be more extreme. The sea level is also rising, approximately 1/8 inch every year. This will cause increased inundation of ocean water into low-lying areas. In fact, storm surge and wave runoff is likely to cause more of a problem than inundation since the built areas will be affected by storm waves. Other impacts include: erosion of beach cliffs, loss of low-lying land, loss of sediment along beach fronts, salt intrusion into aquifers and surface waters, and higher water tables.

Hazard mitigation planning will have to incorporate regulations and polices that reduce the impacts of storm surge, wave runoff, and sea level increase. Current law, for example, requires structures to be elevated to the 100-year flood elevation, which does not consider sea level rise. New regulations may involve enhanced flood controls, stricter building codes in flood areas, and similar actions that change the types of structures that are built near in high-velocity wave areas, such as the beaches, and in the wetlands. For example, houses along North Carolina’s Outer Banks must be built on piles, and cannot have any permanent walls on the ground floors. Furthermore, uses and activities in these areas will also have to be addressed. The Cape Cod Regional Policy Plan sets performance standards for buildings and restricts enlargement of buildings in the FEMA V flood zones (areas of high wave potential).

 

Conclusion

The Hampton Beach area will continue to be subject to flooding from heavy rains, tidal events, and severe storms. Almost all of the study area is within the flood hazard area as defined by FEMA. In the past, the State and the Town looked to structural solutions to alleviate this problem. At present, the Town with the assistance of FEMA and the state OEM is pursuing a number of actions—structural, regulatory and non-regulatory—to better manage and mitigate flood hazards.

Return to Table of Contents