The records of Lost Lake / Knopp’s Pond are tied to the history of Groton. There is historical mention of hydrological features in deeds recorded soon after the first grant of the Groton Plantation (also called Petapawag) in 1655. Among these early settlers was one James Knap (or Knop), whose lands were demarcated in the 1660’s (Green, 1885). The small pond located on these lands came to be known as Knap’s or Knop’s or Knopp’s Pond. Knopp’s Pond originally occupied only the deepest northeastern basin. There was inlet from an adjacent pond to the south, Springy Pond. The outlet stream of Knopp’s Pond flowed northerly through Cow Pond Meadows to Cow Pond (a.k.a. Whitney’s Pond). These meadows are mentioned in town records dating from 1664. The outlet of Cow Pond was Cow Pond Brook, which flows into Massapoag Pond and, eventually, the Merrimack River.

In Cow Pond meadows the stream arising out of Knopp’s Pond was joined by a small tributary arising from the west. This tributary passed through a hydrologic feature known as Way Pond in colonial times, and drained the area known as Indian Meadows (south of Indian Hills ?) by Butler (1848). While it may have at one time been referred to as Way Pond Brook (Green, 1912), the current topographic map does not show a name for this tributary.

The other major stream draining to Cow Pond Meadows was the outlet of Martin’s Pond (another pond named after an early Groton settler). Martin’s Pond Brook presently drains this pond to the southeast. It joins another stream, formerly known as Brown Loaf Brook (May, 1976), near the old site of school-house #9 (Butler, 1846). Records indicate that the drainage from Martin’s Pond Brook originally passed to the west into James Brook via Half Moon Meadows, north of Gibbet Hill. Thus, drainage from this pond was diverted from the Nashua to the Merrimack River watershed. This stream has had its present course since the late 1700rs (Butler, 1948; Green, 1912; May, 1976).

The hydropower potential of these streams was soon tapped by local inhabitants in several enterprises. The stretch of land between Cow Pond Meadows and Cow Pond was the site of a dam and associated saw-mill, which was succeeded by a paper-mill. This paper-mill was taken down about the end of the Civil War (Green, 1912)
At some point in the nineteenth century, possibly around the late 1860’s, the water rights to Knops Pond were apparently secured by the Harbor Manufacturing Company, a mill concern based in Nashua, New Hampshire. This company used the waters of the Merrimack and wanted to insure a more seasonally constant water supply for its mills. A wooden dam was constructed at the narrowest constriction between Knops Pond and Cow Pond Meadows to impound the waters of Knops Pond. It remains are still clearly visible beneath the water surface of the water at this location. This impoundment enlarged the size of Knops Pond, back flooding Springy Pond and making a direct surface connection between the two. Reports of abundant stumps on the shores of Knops Pond indicate that forested areas were impacted (MA DFW, 1911). A map of the area from the 1880’s indicates the increased size of Knops Pond relative to Duck Pond (Green, 1885). The enlarged pond occupied about 55 acres (MA DFW, 1911; Green, 1912)

Near the end of the nineteenth century (1896 or 1897), additional water rights were secured by Vale Mills of Nashua, New Hampshire. A second dam was constructed at the highlands between the outlets at the northern end of Cow Pond Meadows. This created a large body of water in Cow Pond Meadows, latter referred to as Lost Lake or Mountain Lakes. The owners and controllers of the water rights were mentioned in MA DFW notes (1928) to be Gardner Beardsall Corporation. Some later mention is made of water rights owned by International Paper Box Machine Co, but the date of this correspondence was not available (MA, 1960).

It was before World War I that the building of cottages on both Lost Lake and Knops Pond’ commenced. By 1911, there were sufficient cottage owners to complain about the occasional draining of Lost Lake (presumably for downstream water power) Foul odors and poor appearance were the chief complaint. These may have been produced by the decomposition of organic material left in the meadows at the time of flooding. Another complaint was the worry that the drained areas were breeding places for mosquitoes and “much malaria is caused” (MA’DFW, 1911). Needless to say malaria is not a common problem in New England, and this concern was more likely linked to the American public’s awareness of “yellow fever” at the on-going Panama Canal construction, than to any local occurrence of this disease.

The expansion of the railroads had an influence on Lost Lake Knops Pond and its development as a summer resort. The Ayer Lowell Street Railway or trolley car followed the present Route 2 and passed about a mile to the south (MA DFW, 1911). Alternatively, there was the Stony Brook Railroad stopping at North Littleton Station, just 2 miles to the south. With this increased ease of access, holiday and summer excursions from Boston and the suburbs became more frequent.

The popularity of Lost Lake / Knops Pond as a vacation spot led to rapid development of the area, particularly the northern end. Real estate developers sub-divided larger tracts into small lots which they sold for summer homes. The major sub-division was owned by the Lost Lake Development Co. (Collins, 1985). These undeveloped lots were widely advertised and could often be purchased relatively cheaply. The name Mountain Lakes or Lost Lake was coined by these developers, undoubtedly to provide more distinction to the water body than Cow Pond Meadows could provide.

It was during this period (1900’s to the 1920’s) that many of the buildings in the watershed were built. Primitive “camps” were improved by their owners into summer cottages. However, as there were few building codes or standards for sanitary facilities during those days, these cottages were built with insufficient concern or acreage for protection of the ground water. In this somewhat haphazard fashion, Lost Lake / Knops Pond developed as a popular summer resort. Much of the lands surrounding the lake were converted from forested to part-time residential.

The Great Depression led to a reshuffling of property rights in the Lost Lake / Knops Pond watershed. One critical event was the bankruptcy of the Lost Lake Development and the foreclosure of the property by the Highland Trust Company in 1932 (Collins, 1985). This bank subsequently failed and the property assets were distributed by the Commissioner of Banks. Acquisition of the water and flooding rights to Lost Lake was obtained by Groton Ridges Lakes, Inc. in 1934. This corporation owns the dam and right to maintain it (Collins, 1985). Other properties were later conveyed to the Groton Conservation Trust, including roads and common areas. The management and maintenance of the dam was the responsibility of the The American Baptist Churches of Massachusetts for many years as they were thought to hold a controlling share of the above named corporation. However, a thorough search of State records failed to uncover the incorporation records of Groton Ridges Lakes, Inc and the Town of Groton took the dam and surrounding land by eminent domain in the early 2000s. The responsibility of the dam shifted to the Groton Highway Supervisor.

The Depression also caused a fundamental demographic change to the Lost Lake / Knops Pond area. Economic circumstances forced the conversion of many of the summer cottage to full time homes (a trend which continues to this day). These conversions only proved how woefully inadequate the existing sanitary systems were to year-round usage, particularly in the steep, excessively drained soils characteristic of the watershed. In other cases, the cabins were virtually abandoned, and left to decay. The present condition of this area still reflects this mosaic of improved cottages co-existing with poorly-maintained or failing structures.

The present uses of Lost Lake / Knops Pond are mainly swimming, boating, fishing and skating. Swimming used to be a popular activity but has decreased significantly as the result of severe weed infestation. There is a public beach maintained on the lake, a large institutional beach (Grotonwood), a “locals” beach, and numerous small private beaches. The public beach is Sargisson Beach, located on the southeast shore of Knops Pond. This beach was opened for use during the summer months, and swimming lessons were conducted there. Unfortunately, budget considerations of the Town of Groton closed this beach a few years ago. The Grotonwood beach is located on the western shore of Lost Lake, and is used by the guests of the camp. Another small beach is located at the northern end of Lost Lake near the outlet structure. This beach, locally nicknamed “Baby Beach,” has limited access and is used only for local resident bathing. A floating dock usually is placed just offshore during the summer.

Fishing is a very popular spring and summer activity, due to state stocking and the easy access to the lake off Route 119. A developed boat launch, originally created by the Squannacook Rod and Gun Club (MA DFW, 1960) is located on the northeast side of Lost Lake, in a secluded cove. It is now owned by the State of Massachusetts. Trout are stocked in the spring, and this is the period of greatest fishing activity. An aerial creel survey (4/22/77 through 6/25/77) indicated about 11,500 hours of angling activity (MDFW, 1978). Declining trout catches and increased competition for the water surface reduces the popularity of boat fishing in the summer. However, shoreline fishing for pan fish is popular throughout the summer. Recent recommendations for improvement of the fishery included increased signage and acquisition of an additional boat ramp at the southern end (MDFW, 1978).

Boating is a preferred activity and ranges from powered boats to rowboats or canoes to sailboats. Water-skiing down the length of Lost Lake is a popular activity. This activity is restricted in Knops Pond by the placement of two low speed (6 mph) checkpoints, marked by warning buoys. Despite this precaution there have been boating accidents (e.g. September 1987) on the lake, mostly due to high operating speeds and the restricted line-of-sight caused by the many small coves. Activity tends to be concentrated in the late afternoon and evening hours, as well as the weekend. Small sailboats are occasionally seen on the lake, and jet skis are in evidence.

Activities during the winter month’s center generally upon ice-fishing and skating. The good access to the lake and large fish population makes this a popular and “substantial” ice fishery (MDFW, 1978). Skating areas are established on the ice during the winter months.

While the lake was and continues to be the center of many recreational activities, concerted efforts to manage the lakes have only recently emerged. An attempt to reduce the weed growth was made in summer 1987, when the Massachusetts Clean Lakes Program funded a plant harvesting via hydro-raking. This was done in public areas and was available informally for private areas. In the past, individual abutters may have practiced some management of their shorelines. With regard to chemical control, fisheries records indicate that rotenone was sprayed in 1960 to assess and control the fish population as part of a reclamation effort (MDFW, 1960).

The Diagnostic/Feasibility Study for the Management of Lost Lake/Knops Pond prepared for the Town of Groton in 1989 offered a number of alternative strategies to reduce non-native invasive weed growth. The precursor organization to the Groton Lakes Association, the Clean Lakes Committee, selected drawdown as the preferred method. Permission of the Conservation Commission to draw the lake down an additional four feet in the winter was asked for. They agreed to an increase of two feet. A siphon was constructed and installed by the dam. Unfortunately, attempts to lower the lake level below its normal winter level were thwarted by residents complaining of loss of water supply. The order of conditions called for the siphon to be shut down until those residents’ problems could be addressed. The required volunteer manpower required by the order of conditions to provide people with water outstripped the efforts for a successful attempt to draw the lake down and attempt to kill the invasive weeds through winter frost.

In the meantime, a new invasive was identified at or near the State’s boat launch, Fanwort or Cabomba, most likely brought in on a boat launched at this site. A limited herbicidal treatment was conducted after securing permission from the Conservation Commission. It failed and Fanwort continued to spread far and wide in the lakes. In 2002, an herbicidal treatment of the entire lake for the control of milfoil was approved and was very successful in reducing the weed infestation. Unfortunately in 2004 the Massachusetts Natural Heritage Endangered Species Program stopped all attempts to control the spread of the non-native invasive weeds because of claims that there was an endangered aquatic plant present in the lake. This lull in the battle to keep the weeds from destroying the pond allowed the milfoil to return and fanwort to expand its territory. The weed harvester owned and operated by the Groton Lakes Association tried to keep up with the new growth. Harvesting became a means to an end to keep the waterways open and beaches and waterfronts clear for recreational activities.

The Groton Lakes Association hired Aquatic Control Technology in 2011 to conduct a biological survey of Lost Lake/Knops Pond and come up with management alternatives. All previous methods of control have failed, -hydroraking, drawdown, benthic barriers and harvesting. Herbicidal treatment became the only viable method left to cope with this accelerating problem.

In 2011, the harvester did yeoman’s service to keep the waterways open, but the weed regrowth in 2012, partly due to warmer than normal winter and no freezing action to kill weeds, has seen a quantum leap in the density of milfoil and Cabomba in the spring of this year.

The plan now is to treat the lake, hopefully in 2013, with Sonar (Fluoridone) a reservoir approved herbicide. It attacks and kills the roots of the two main invasives – milfoil and Cabomba. It has been safely and effectively applied in primary water resource areas such as Spectacle Pond in Littleton, and Sandy Pond in Ayer, Neponset Reservoir and many other drinking water resources throughout the state and country. Town and private wells had no traces of the herbicide.

Spot treatment of the lake will be necessary in subsequent years until the infestation has been controlled. Management of the public access launch will have to be addressed to minimize or even better eliminate the re-introduction of these common invasives. This means the boat launch will have to be managed by volunteers or paid employees with revenue generated by launching fee that would be applied for all who use it, including Groton residents.

On-going education of lakefront residents will also be required that will lead to better stewardship so as to minimize erosion and reduce the use of nutrients that enrich the waters.

This “Lake History” was taken from the ‘Historical Lake & Land Use” section of the Diagnostic/Feasibility Study for the Management of Lost Lake / Knops Pond Prepared for the Town of Groton & the Mass. Division of Water Pollution Control by Baystate Environmental Consultants, Inc. It was updated by Alex Woodle in 2012.