3/7/2023 0 Comments Jetties and breakwatersMany of the changes have been imposed by human activity, in particular through (a) the installation of breakwaters to stabilize the entrance of the estuary, (b) the creation, maintenance and deepening of a 145-mile navigation channel, and (c) significant changes of upstream river discharge and sediment inputs via extensive flow regulation with a network of dams. Modern and predevelopment bathymetries are substantially different in the Columbia River. Baptista, in Encyclopedia of Physical Science and Technology (Third Edition), 2003 IV.B Bathymetry Thumbnail image: Photo, 2019, by David W. This view of the Court Street groin at high tide is from Google Maps.Ībove and below: The Court Street groin in 2019. The Court Street groin at low tide in 2010. In the Provincetown Building Department archive. Did you think they were placed there because they were aesthetically pleasing, or for little kids to climb on? Also, what type of vessels travel that close to shore along that stretch of beach at a rate of speed that it would be considered to be a ‘navigational hazard’? To do so would be idiotic, not to mention illegal.”Ī typical section of a groin (or jetty), from “Proposed Shore Protection Provincetown,” September 1939, Division of Waterways, Department of Public Works of Massachusetts. “Look what happened to Herring Cove right after they removed all the ones that were there. “Without them, a lot of houses and buildings along Commercial Street would soon be gone, because their exact purpose is to stop the natural erosion of sand,” the fisherman Wayne Martin said on 17 January 2021. To the extent they have preserved property owners’ beachfronts, however, the groins are considered a success. “Groins become navigational hazards when they become submerged at high tide,” the plan stated. There are other perils, according to the Provincetown Harbor Management Plan Amendment of 2018. Gambols on the groins were officially banned in 1953 by the Massachusetts Division of Beaches, in Chapter 666 of the General Laws: “Climbing upon or over or walking along breakwaters, jetties, or groins is prohibited.” “I fell on that jetty and cut my arm open once. “My aunt used to take us to the Court Street beach,” Lisa King recalled in a Facebook comment thread on 17 January 2021, responding to this article. They create curving pockets along the shoreline as sand erodes from the leeward side of one groin and is deposited against the windward side of the next groin along. As far as their many critics contend, they do their job all too well. Groins are designed to mitigate the drift of sand along a beachfront. 7 in 1939 by the state Division of Waterways. This particular groin, near the foot of Court Street, was designated Jetty No. Many of the stones used for these groins came from Quincy, which was the source of the boulders used in the enormous West End Breakwater. Each was originally 125 feet long, 12 feet wide, and 3 feet high. The Speedway Construction Company of Boston built the second group, in the West End. The East End groins were built first, by Louis Byrne of Dennis. Barnstable County and the Commonwealth of Massachusetts picked up the rest of the tab. They were constructed from 1939 to 1940 at a total cost of $30,000 (about $550,000 in today’s money). Like the giant teeth of a sand comb, a series of 26 stone jetties - more accurately called groins - rake the beaches of Provincetown Harbor.
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