As Hurricane Threat Builds, Has Complacency Set In about Flooding?

It has been some time since a major flood struck Northampton. That doesn’t mean the threat has gone away. On the contrary, AccuWeather believes that conditions are favorable for New England to experience a significant hurricane in the relatively near future [2006 article]:

“The Northeast is staring down the barrel of a gun,” said Joe Bastardi, Chief Forecaster of the Hurricane Center. “The Northeast coast is long overdue for a powerful hurricane, and with the weather patterns and hydrology we’re seeing in the oceans, the likelihood of a major hurricane making landfall in the Northeast is not a question of if but when.”

…The current cycle and above-normal water temperatures are reminiscent of the pattern that eventually produced the 1938 hurricane that struck Providence, R.I. That storm killed 600 people in New England and Long Island. The 1938 hurricane was the strongest tropical system to strike the northeastern U.S. in recorded history, with maximum gusts of 186 mph, a 15- to 20-foot storm surge and 25- to 50-foot waves that left much of Providence under 10-15 feet of water. Forecasters at say that patterns are similar to those of the 1930s, 40s and 50s when storms such as the 1938 hurricane, the 1944 Great Atlantic Hurricanes and the Trio of 1954–Carol, Edna and Hazel–battered the coast from the Carolinas to New England. The worry is that it will be sooner, rather than later, for this region to be blasted again…
Bastardi repeated his warning in 2007, writing:

New England is fair game from now on until 2025, although the most frequent threats to the Northeast should be later in the run of the cycle. Last year, the statement that two major hurricanes would hit the Northeast within the next 10 years, sooner rather than later, and the worry as of this year, fortunately did not carry weight last year. The summer temperature and hurricane pattern was so close to 1954 it can mean one of two things … we were unlucky in ’54 or lucky last year. Ernesto came on the exact date of Carol, but the track some 100 miles west of Carol up the East Coast spared what should have been a devastating hurricane. As it was, damage to the coastal areas north of Cape Hatteras was greater than Floyd. Florence was 250 miles east of Edna’s path on the very same day as 1954. The number one target area last year, relative to averages, was the Canadian maritimes. In addition, the Gray/Klotzbach objective raw guidance, which I weighed in as far as a number frequency to landfall relationship I have developed, was only 10.6 seeing well in advance the major parameters as they have developed them in saying this was not a huge number year. The moral is that the East Coast is open, but I do not at this time have the same kind of support I had for last year of shifting tracks east. Since I believe we are in the early to middle stages of the AMO [Atlantic Multidecadal Oscillation], the backdrop of the late 30s is the canvas on which the hurricane forecast is being painted, but it takes until spring is done for me to really hone in on where I think where impact is most likely.
Following the Hurricane of 1938, another memorable hurricane-related event was the rainfall that accompanied Hurricane Diane in 1955:

The largest single-day precipitation event recorded in New England was 18.15 inches at Westfield, Massachusetts, produced by Hurricane Diane in late August 1955. In all, this single event produced 19.75 inches of rainfall at Westfield over three days (18-20 August 1955), which is the single largest rainfall event in New England (Keim, 1998). One-day rainfall totals from this event were in excess of 10 inches at numerous sites in Massachusetts and Connecticut. It was particularly damaging because the storm followed the heavy rains produced by Hurricane Connie in southern New England on 12-13 August. As a result of these two storms, the month of August 1955 went into the record books as one of the all-time record months for total precipitation, with values reaching over 25 inches for parts of Massachusetts and Connecticut…
The Republican recalled the resulting devastation in a 2005 article:

Two days later, after massive floods had ripped apart the valley, which was ground zero for the storm’s damage, a Daily News reporter flew over the region and offered these descriptions of what Diane had accomplished.

“Roads were washed out almost everywhere, bridges were down, railroad tracks were buckled and whole neighborhoods were inundated. Here and there a house leaned crazily. Cars could be seen stranded, abandoned on broken roads, and leaning into rain-made chasms…”

Ann S. Merrit of Russell, Strickland’s sister, said the “noise of the flood was almost surreal.” “Instead of the splashing and rushing sounds of moving water, there was a constant roar as tons of rocks and debris rushed down the Main Street area. At least one car, a Ford sedan, went swirling by and stopped when it hit a telephone pole at the town green. We finally made it up to Route 20, and spent the rest of the night with friends on high ground,” she said.

Friday morning, a state of emergency was declared for Massachusetts west of Worcester by Gov. Christian Herter. Dozens of bridges had been swept away and numerous dams, many of them private mill dams, had let go, sending walls of water and debris, from tree trunks to automobiles, hurtling downstream into residential neighborhoods and business districts…

“The next morning, George and I headed out of there coming down Loomis Street to the brook where there was a bridge. This little brook is normally something you can wade across. But we were chest deep in water…
One lesson from this experience is that bodies of water, even innocuous-looking little streams, should be accorded respect and given their space. This includes Millyard Brook, which runs close to Kohl Construction’s proposed condo development. When left alone, wetlands mitigate flooding by absorbing floodwaters and slowing them down.

Infill sounds great on paper, but when it means paving over green space in downtown Northampton, it runs contrary to sound flood mitigation practice. The reality is that much of the remaining green space in downtown is in low-lying areas that are most susceptible to flooding. It makes sense to go along with the collective wisdom of the past 350 years and leave them undeveloped.

See also:

The Great Flood of 1936: Photo Gallery
Views of Coolidge Bridge, Main Street, Pleasant Street…

Alewife Study Group: Impact of Development on Wetlands and Flooding
…As a direct result of development on the Alewife flood plain and its low elevation, there is periodic and significant flood damage in the surrounding communities. A 1981 study by the MDC found property damage in the Alewife area to be the highest of any portion of the Mystic River watershed of which it is a part.

During flood events at Alewife, the Mystic River backs up into the Alewife Brook and Little River areas. Flood waters from Belmont also empty into this area during storm events. During the flood of October, 1996, the Alewife Brook flooded over the Alewife Brook Parkway and into North Cambridge neighborhoods. East Arlington neighborhoods adjacent to Alewife were also inundated with flood water. The Arthur D. Little parking lot was covered by several feet of flood water…

Wetland Function and Values (PDF, emphasis in original)
Wetlands help control floodwaters by storing excess water during heavy periods of rain and snowmelt. During and after a storm, rainwater flows to low-lying areas, which may be our floodplains and swamps. Trees, roots, soil, and other vegetation hold the excess water until it can be slowly released into streams and rivers. This process helps reduce the risk of flooding into nearby homes.

Urban wetlands are particularly important because they help prevent flooded basements, parking lots, and roads. When wetlands are filled or altered, their ability to hold floodwaters is crippled. In 2001 the Pocasset River Watershed suffered one of many severe floods. This flooding was due to approximately 700 acres of wetland loss since 1939, much of which was floodplain loss. As a result, in the highly urbanized and industrial areas of Johnston and Cranston, there is nowhere for the water to go during heavy periods of rain resulting in flood damage to private properties. It is easier and less expensive to maintain existing wetlands than it is to engineer and create stormwater drainage systems to handle the water.

UK Blog: Floods and Development, 7/23/07
…the LibDem Councillors, at a recent Cabinet meeting produced documents promoting an increase in “high density developments” in Teddington, Whitton and Twickenham. This is an issue I will come back to as a separate debate on planning, but given the flood risks in the area, should we really be concreting over our green spaces and further reducing drainage potential and increasing flash flood risk?