The New Hampshire Coastal Program (NHCP) and the New Hampshire Office of Emergency Management (OEM) released a report in 2001 written by Dr. Larry Ward, Jackson Estuarine Lab entitled, "A Preliminary Assessment of Tidal Flooding along the New Hampshire Coast: Past, Present and Future." Of interest to New Hampshire's coastal residents and officials is the increase in potential risk to tidal flooding over the next century due to sea level rise.
A number of recent studies of global sea level change indicate the average level of the world's oceans will increase significantly by the end of this century (2100). A two-foot rise is well within the predicted ranges. What does this mean for New Hampshire? Although an increase of two feet in mean sea level by 2100 in itself does not seem overwhelming, it is important. The impact of sea level rise on the 10-year flood event (a flood that has a 10% chance of occurring every year) and the 100-year flood event (a flood that has a 1% chance of occurring every year) is clear. Refer to the table below.
|Town||Acreage affected by 10-yr flood before 2002||Acreage affected by 10-yr flood after 2100||Acreage affected by 100-yr flood before 2002||Acreage affected by 100-yr flood after 2100|
|Portsmouth||70 acres||140 acres||102 acres||193 acres|
|Hampton||551 acres||825 acres||709 acres||950 acres|
|Seabrook||266 acres||442 acres||367 acres||517 acres|
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