If infill is to mean adding more impervious surface to the already built-up areas of Northampton, this will increase pressure on our man-made stormwater drainage system. The limits of this system were on display this week, as snow, sleet and nearly 3 inches of rain came to Pioneer Valley. Today’s Gazette reports:
Water, water everywhere
…”The rainfall carries floating slush to a catch basin,” said Amherst Public Works Superintendent Guilford Mooring. “We clear something up and it clogs up again. We’ve been working since last night.”
Ditto for Easthampton Public Works Superintendent Joseph I. Pipczynski: “It’s just a nasty storm,” he said. “You unplug the basin, they go down the street, the slush covers the basin again and you’ve got another lake…”
It’s more than just inconvenient for travelers when water accumulates on the streets. Today’s Republican reports how it can damage infrastructure underground:
Snow, rain flood streets, roofs
…Three sections of [Springfield], Wilbraham and King Streets near Springfield College, Carew and Main streets in the North End, and Belmont Avenue near Forest Park, lost power midday when rain water from flooded streets seeped into underground electrical vaults, [Western Massachusetts Electric Company spokesman Kenneth S. Garber] said.
“There was just so much water on the streets, it had nowhere else to go,” he said…
Public Works employees spent much of the day trying to open up the blocked drains, officials said…
As former Northampton City Councilor Alex Ghiselin remarked last year, “Growth that erodes the natural system isn’t smart… Wetlands do not need to be maintained; they just need to be protected.” (Sources: Republican, Gazette)
Gazette: “Wait for all clear: State of sidewalks along Northampton street a concern for many” (1/30/09)
At 3:30 Thursday, [DPW Director Edward] Huntley dispatched a crew to the corner of King and Summer streets, where a river had started to form due to blocked drains.
Topographical Map Shows How Kohl Condo Proposal Will Eat Into a Rare Stand of Mature Trees in Downtown
The following view dramatizes the considerable amount of impervious surface already surrounding the area off North Street that Kohl Construction proposes to develop, especially around King Street and the Coca-Cola plant. Kohl’s “infill” project will convert a significant amount of the remaining greenspace to impervious surface. The presence of Millyard Brook shows that this area serves as a natural sink for water in the neighborhood.
Photo Essay: Millyard Brook Swells with Water in Winter
Northampton’s Flood and Natural Hazard Mitigation Plan: Wetlands Buffers of 100 Feet Are an Effective Flood Mitigation Strategy and Should Be Consistently Enforced
In general, a core problem for infill in Northampton is to avoid placing large numbers of people and structures in low-lying areas downtown that may be at risk for flooding. As the plan states, “In recent years, heavy rainstorms have caused significant problems in more urbanized areas as increased development inhibits proper drainage and existing or poorly maintained water systems cannot handle increased stormwater runoff.”
Northampton Open Space Plan: “This loss of habitat and natural flood buffering areas is Northampton’s most serious environmental problem”
Greening Smart Growth: The Sustainable Sites Initiative
Even in highly urban settings, the functions of healthy systems can be imitated and natural processes can be harnessed to provide environmental benefits. For instance, New York City trees intercept almost 890 million gallons [3.3 billion liters] of rainwater each year, preventing that much runoff from entering storm sewers and saving an estimated $35 million annually in stormwater management costs alone.
EPA: Wetlands and Flood Protection
Wetlands within and downstream of urban areas are particularly valuable, counteracting the greatly increased rate and volume of surface-water runoff from pavement and buildings…
A one-acre wetland can typically store about three-acre feet of water, or one million gallons. An acre-foot is one acre of land, about three-quarters the size of a football field, covered one foot deep in water. Three acre-feet describes the same area of land covered by three feet of water. Trees and other wetland vegetation help slow the speed of flood waters. This action, combined with water storage, can actually lower flood heights and reduce the water’s destructive potential. (Source: EPA)
The Economic Value of Wetlands: Wetlands’ Role in Flood Protection in Western Washington
Metro Portland’s Long Experience with Smart Growth: A Cautionary Tale
…Portland is currently laboring to finance a multi-billion dollar consolidated sewer outflow system to accommodate the effects that dense (and impervious) development is having on surface water accumulations in the region.