{"nrhp_refnum":"89002289","name":"Ashland Dam and Spillway","other_names":[],"category":"structure","location":{"address":"N end of Ashland Reservoir in Ashland State Park","address_restricted":false,"city":"Ashland","county":"Middlesex County","state":"MA","lat":42.24606913900007,"lon":-71.45952212311612,"geom_source":"nps_gis"},"listed_date":"1990-01-18","is_nhl":false,"nhl_designated_date":null,"areas_of_significance":["Community Planning and Development","Engineering","Politics/Government"],"significance_levels":["state","local"],"summary":{"what_it_is":"An 1885 earthen dam and granite spillway in Ashland State Park, in the southern part of Ashland, Massachusetts, forming the Ashland Reservoir on Cold Spring Brook as part of the Sudbury River water supply system.","why_significant":"The dam and spillway are tied to the Sudbury River supply, the second source tapped by the Metropolitan Water Board. They are good examples of late 19th-century water technology and design. The granite spillway is considered outstanding for its sculptural, almost natural look like a stream through the woods.","narrative":"Built in 1885 in what is now Ashland State Park, this dam and spillway hold back the Ashland Reservoir across the valley of Cold Spring Brook. The dam is an earthen embankment 54 feet above the flooded meadow and 83 feet above bedrock, with a concrete core wall and a waterside covered in concrete paving and riprap. The 630-foot spillway is built of granite rubble masonry with heavy granite steps laid on concrete, and it carries overflow down to the brook. Its appearance is unusual: although manmade, it resembles a brook running through the woods. The structures were part of the Sudbury River supply and storage system begun in the 1870s, which supplied metropolitan Boston and was the second source tapped by the Metropolitan Water Board. They were recognized as good examples of late 19th-century water engineering, with the spillway standing out. The gatehouse was lost in 1976, and the reservoir later became a state park.","period_of_significance":null,"architect_builder":null,"architectural_style":null,"criteria":["A","C"],"status_note":"Condition is described as good. The gatehouse was demolished in 1976 due to vandalism, and the reservoir was turned over to the Commonwealth for use as a state park.","vacant_flag":null,"machine_generated":true,"model":"claude-sonnet-5-5","prompt_version":"v1.0-2026-10-29","generated_at":"2026-10-29 02:13:01.952194-05","source_pdf":"https://s3.amazonaws.com/NARAprodstorage/opastorage/live/8/7920/63792008/content/electronic-records/rg-079/NPS_MA/89002289.pdf"},"photo":{"url_800":"https://nationalhistoricalregister.com/media/89002289/4274eed739-800.webp","url_1600":"https://nationalhistoricalregister.com/media/89002289/4274eed739-1600.webp","licence":"CC BY-SA 4.0","author":"User:Magicpiano","credit_html":"<a href=\"https://commons.wikimedia.org/wiki/File:AshlandMA_AshlandParkSpillway.jpg\" rel=\"noopener\">User:Magicpiano</a>, <a href=\"https://creativecommons.org/licenses/by-sa/4.0\" rel=\"license noopener\">CC BY-SA 4.0</a>, via Wikimedia Commons","source_page":"https://commons.wikimedia.org/wiki/File:AshlandMA_AshlandParkSpillway.jpg"},"district":null,"sources":{"nps_snapshot_date":"2026-05-22","nara_catalog":"https://catalog.archives.gov/id/63792008","wikipedia":"https://en.wikipedia.org/wiki/Ashland_Dam_and_Spillway","wikidata":"https://www.wikidata.org/wiki/Q4805243"},"indexable":true,"url":"https://nationalhistoricalregister.com/massachusetts/middlesex-county/ashland-dam-and-spillway-89002289/"}