Water Chestnut Eradication in the Alewife Brook Watershed

• Inception - Stewart Sanders led me on a kayak tour from Little Pond to the Mystic River and back late fall of 1999.  Along the way I noted several patches of water chestnuts which appeared small enough to remove by hand.  I decided to attempt a three-year eradication of this weed in the Alewife Brook watershed if all permits and permissions could be obtained.
  
• Current Conditions - Small numbers of plants were seen in Little Pond, Little River, and Perch Pond.  Large mats existed in Blair Pond and Alewife Brook.  Cities where harvesting is planned include Arlington, Belmont, Cambridge, and Somerville.
  
• Trapa natans - European water chestnut served as a food source in some early human societies.  In Massachusetts it is an introduced, invasive species classified as a noxious weed in the 1990 agriculture code.  Large mats of the plant can completely choke light from a waterbody and halt all navigation.
  
• Proposal - During the growing seasons of a 36-month period beginning mid-2000, volunteers will use hand methods to remove all water chestnut plants found in the Alewife watershed.  Monthly patrols will attempt to ensure no new viable seeds have time to form.  A three-year time is required because seed from earlier years may remain viable at least this long.  Yearly checkups after this would be advised.
  
• Methods - Harvesting will take place entirely from non-motorized craft such as canoes and kayaks.   Hand pulling will be the main method, but hand tools may be used in deeper water to snag the stem as near the bottom as possible.  A potato rake has been recommended.  The plants will be collected in plastic recycling bins for hand transport over any fragile bank area. 
  
• Disposal - The City of Cambridge has agreed to accept this waste through its regular curbside yard waste collection program.  Kaknes Wood Products in Woburn composts the city's yard-waste and has also been composting the Watertown Yacht Club's harvest for several years.  The waste is first put through a grinder which destroys the very large (1-1/2") seeds.  The city's waste transporter will be fully informed of the slight contamination of this waste with sewage, and all harvests will dry at least overnight to further reduce risks.  Barrels will be filled to 2/3 capacity to avoid spillage and any need for direct contact.  If for any reason these composting plans should fail, the City of Cambridge will accept the harvest as garbage to be landfilled.  Attached is a letter from the Cambridge DPW committing to accept this waste for the first year.  Extensions are expected to be obtained as needed, and volumes should fall sharply in the last two years of this program.
  
• Permits - An MDC permit for activity affecting MDC-owned waterways is required from Don Guidoboni in their permitting office.  I have applied for this and have verbal support from the MDC Planning Office.  Approval letters from Conservation Commissions in the four towns affected to Mr. Guidoboni are needed.
  
• Schedule - Beginning mid-April 2000, scouting trips will verify locations and sizes of significant clumps.  As often as seems useful, but at least monthly beginning mid-May and continuing through October, all visible plants will be harvested and the local water bodies will all be checked for any new plants.  This will continue for three years, hopefully with significantly less effort required in later years.  It is hoped that if surveys locate more plants in the Alewife Brook watershed this work might be expanded off MDC land in later years.
  
• Studies - Note the growth characteristics and maturation dates in local waters and compare them with those reported inland at efforts in the Connecticut River valley to determine best times to harvest.  GPS coordinates, number of plants and weight of harvested plants will be recorded at each infestation so efficacy can be determined in out years.
  
• Surveys - At least once in mid-summer, all other waterbodies in the Alewife Brook watershed will checked for water-chestnuts.  This includes, but is not limited to: Spy Pond, Menotomy Rocks Pond, Clay Pit Pond, Black's Nook, Little Fresh Pond, and Fresh Pond.  A report on the harvest, studies, and surveys will be sent to the MDC and four conservation commissions yearly during this three year process.
  
• Personnel - I expect to do the bulk of this project individually, as I am retired and able to commit to harvesting at the most propitious times.  On parts of the project, up to five additional volunteers may be used.  Only adults fully apprised of and equipped for the risks will be used.
  
• Protection - All of this waterway is currently contaminated with sewage which will likely not all be cleaned up even after three more years.  I will personally be wearing shoulder-length gloves when reaching into the water to harvest plants.  I currently kayak these waters and regularly get my hands and gloves wet on the paddle, and splash a couple of pints into the boat and on myself, and take no precautions other than a good shower afterwards.  Some volunteers may opt for a surgical mask to guard against aerosol droplets, while others may use lab goggles to ward against splashes in the eyes.
  
• Wetlands Protection - I see two points of concern for the wetlands: 1) avoid impact on the shoreline and bank area when moving tools, plants, and personnel to and from the water.  There are docks at Little Pond and on the Mystic River which allow the bank to be avoided entirely.  For access without docks, such as Blair Pond, all equipment and plants will be lifted across the shoreline and stable areas of bank will be used for entrance and exit.  2) minimize disturbance and resuspension of sediment.  Harvesting will be from small boats to completely avoid the effect of walking across the bottom.  The stems are said to often break off without the roots, but sediment dislodged by any roots removed will largely fall directly back into place.  The dry days chosen for clean-water reasons will also have lower flows and little sediment transport.  The removal of these plants from the yearly biomass will reduce sediments and oxygen depletion in future years.
  
• Goals - The simple goal is eradication within an entire watershed, to show it can be done and challenge others to extend the effort watershed-by-watershed.  Near term; methods, timing and tools for hand harvesting will be tried and reported on.  The recording of locations, numbers, and amounts will enable any results to be clearly measured.
  
• Benefits - Elimination of this invasive plant will greatly reduce sediment and Biological Oxygen Demand from decaying plants.  The removal of large mats will improve navigation, allow light into the water column, reduce nighttime oxygen depletion caused by plants, and stop localized trapping and buildup of sediment which creates sandbars.  Yearly reports will document locations, numbers, and mass of plants removed, and any further waterbodies where infestations are found.  Maturation rates and ease/efficiency of harvesting on various dates will be recorded as well as the efficacy of various implements used on occasion.  All plans and results will be posted on the internet to encourage expansion of harvesting to other areas and groups.

Roger Frymire
22 Fairmont Avenue
Cambridge 02139-4423
617-492-0180
ramjet@alum.mit.edu

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