Editing Merrimack River (section)

== May 2006 flooding ==
{{main|2006 New England flood}}
[[Image:Merrimack-flood-2005.jpg|left|thumb|Merrimack River in flood, October 2005, [[Manchester, New Hampshire]]]]
While the Merrimack River is prone to minor [[flooding]], on May 15, 2006, rainfall raised the river more than {{convert|8|ft|m|1}} above flood stage, forcing evacuations, damaging property, and breaking the main sewage pipeline in the city of [[Haverhill, Massachusetts]], dumping {{Convert|35E6|gal|L}} of raw sewage waste into the river per day. Reports of total rainfall vary, but most areas appear to have received around a foot of rain with some areas receiving as much as {{convert|17|in|cm|0}}.

According to ''The Boston Globe'', around 1,500 people evacuated their homes to escape the flood.<ref>{{Cite news| url=http://www.boston.com/news/local/massachusetts/articles/2006/05/16/the_saturation_point_flooding_besets_region_more_rain_in_forecast/| title=Flooding besets region; more rain in forecast| author=Brian MacQuarrie| work=[[The Boston Globe]]| date=May 16, 2006}}</ref>

This flood also prompted the [[Massachusetts]] city of [[Lowell, Massachusetts|Lowell]] to install a modern (albeit temporary) flood control gate comprising square steel beams at the site of the historic [[James B. Francis|Francis Gate]], a 19th and 20th-century wooden flood gate. When lowered, the Francis gate seals the city's canal system off from its source on the Merrimack. The Great Gate, as it is also called, was built in 1850 under the direction of [[James B. Francis]]. Considered unnecessary when it was first constructed, "Francis' Folly" first saved the city in 1852 and subsequently in 1936.