Town of Wellesley, Massachusetts - Morses Pond Executive Summary

COMPREHENSIVE PLAN FOR THE

MANAGEMENT OF MORSES POND

EXECUTIVE SUMMARY

Morses Pond is a shallow lake that covers approximately 105 acres, mostly in the Town of Wellesley with a small portion in the Town of Natick. It was created by human action in the early 1700s and has been enlarged several times. Morses Pond is fed by a 5300-acre watershed of mostly developed land, 78% of which is outside Town boundaries. Water enters the pond primarily through tributaries, including Jennings Brook, Bogle Brook, and Boulder Brook. These tributaries all converge in the northern basin of Morses Pond and contribute large loads of contaminants during storm events. Direct drainage from Wellesley and Natick also contributes water and nutrients. Water leaving Morses Pond discharges into Paintshop Pond, Lake Waban and ultimately to the Charles River.

Morses Pond is an important indirect source of public drinking water for the Town through adjacent wells, supplying more than 40% of Town supply. The Town operates a public access area near the outlet at the southern end of the pond, including a beach, swimming area, non-motorized boat launch, and picnic area. Historically, the entire pond has been used extensively for recreational purposes, including swimming, boating and fishing. The Morses Pond wellfield is a major component of the Town's water supply system. Hiking trails are also maintained throughout the Town’s pond property.

Because of the importance of Morses Pond as a multiple use resource, the Town, through the dedicated efforts and cooperation of various departments, boards, commissions, and residents, has actively worked towards the management, improvement, and protection of the pond. Past in-lake management efforts have included the use of algaecides (copper sulfate), phosphorus inactivation (using aluminum sulfate, a coagulant), weed harvesting, and dredging. Monitoring has been performed almost every year since 1981, with sporadic monitoring prior to that date, accumulating a useful database from which management decisions can be made. Outside of the pond, a number of treatment improvements have been made in association with the Town wells adjacent to Morses Pond to meet Safe Drinking Water Act requirements. These improvements protect consumers but have no direct impact on the pond. Town bylaws relating to water supply protection and discharges to the Town storm water drainage system have been developed, and a plan for storm water management has been prepared under the National Pollutant Discharge Elimination System Phase II regulations promulgated under the Federal Clean Water Act. However, some uses of the pond are not adequately supported. The need for a comprehensive plan has been recognized, one which incorporates input from as many parties as possible and examines the complete range of management options for both the short- and long-term.

Problem Statement

Since at least the early 1970s the pond has exhibited symptoms of overfertilization including recurrent algal blooms, reduced transparency, and dense aquatic vegetation growths that have impaired recreational water uses and important aesthetic and wildlife habitat functions. A large watershed area with a substantial portion developed for residential and commercial uses subjects Morses Pond to low water clarity through input of suspended sediment and nutrients that fuel algae growth. The shallow nature of the pond and hospitable soft sediments that have accumulated over many years support dense growths of rooted aquatic plants, with a majority of biomass represented by invading non-native nuisance species. To meet use goals, water clarity must be increased and rooted plant biomass must be decreased.

As a result of these problems, the number of visits to the pond beach has decreased. Boating activity has been significantly curtailed. The aesthetics of the pond environment have been negatively impacted.

Plan Development and Public Participation Process

In 2004, the Board of Public Works, the Natural Resources Commission, and the Recreation Commission formed the Morses Pond Ad Hoc Committee (MPAHC), comprised of representatives of Town boards and civic groups, to develop a comprehensive management plan for Morses Pond. All interested parties have been encouraged to attend public forums offered during plan development. The Town solicited proposals and engaged ENSR Corporation for technical assistance with plan development. The MPAHC has assessed existing conditions, current uses, condition and use goals, priorities for management, and options for achieving the use goals. In deciding which options were most suitable for managing Morses Pond and its watershed, probability of success, cost and acceptability within the existing regulatory framework were carefully considered on various levels.

The MPAHC met regularly and involvement by Town boards, commissions, civic organizations and the public at large was sought in special meetings and forums. A residential questionnaire was used to broaden input on use goals and priorities. Review of management options involved many committee meetings, solicited input from Town boards and commissions, and three publicly advertised meetings to garner input on a wide variety of possible approaches. Options were evaluated based on three key questions:

¨ Is it technically feasible with a high probability of success?

¨ Is it affordable over the short-term and long-term?

¨ Is it acceptable to the regulatory community and a large majority of interested parties?

Evaluation of the draft report encompassed both review of the written report and public meetings to explain the decision process and resulting recommendations, with changes made as needed in response to both written and verbal reviews.

Goals and Priorities for the Use of Morses Pond

While the two general goals of improved water clarity and reduced rooted plant biomass have been apparent to MPAHC members from an early stage of the planning process, a public process of goal development and priority setting was implemented to ensure that as many viewpoints as possible were represented and that important aspects of both the aquatic system and public interest were adequately addressed. The resulting goals and priorities provide guidance for considering possible management actions in light of the range of possible impacts (both beneficial and deleterious) on the complete suite of goals, in the priority order gleaned from substantial input. As determined by this process, goals and priorities include:

1. Top Level Priority:

¨ Drinking Water - Insure that no actions of this plan will have adverse impacts on the long-term quantity and quality of drinking water pumped from the nearby wells.

2. Second Level Priorities:

¨ Contact Recreation - Support Town use of the beach area, promoting water clarity, health standards and aesthetics of the beach area, and promote overall lake conditions conducive to lakewide contact recreation.

¨ Flood Control - Maintain current flood control measures and establish on-going policy measures to achieve flood control.

3. Third Level Priorities:

¨ Non-motorized Boating - Enhance canoeing, kayaking, sailing and rowing, improving and maintaining access for non-motorized boats.

¨ Environment and Wildlife Protection - Protect wetlands and vernal pool habitats, protect wildlife habitat (both within the pond and around it), preserve open space within the watershed area, secure conservation restrictions protecting property within the watershed from development, and prevent bank/land erosion and restore where possible.

¨ Fishing - Enhance fishing opportunities.

¨ Other Non-contact Uses - Enhance non-contact recreational opportunities including walking, nature watching, education and general aesthetics, and maintain access for non-contact uses.

The No Additional Management Alternative and Its Consequences

Taking no additional management actions at Morses Pond means that current approaches will be continued. The result of no additional management action will be that most recreational water use goals will not be met and pond conditions are likely to continue to deteriorate.

Weed harvesting can continue to provide some benefits, but the current harvesting equipment and manpower allocation are inadequate to maintain desirable conditions in all targeted areas. Continued annual hydroraking can minimize plant biomass and debris accumulation in the Town swimming area. Treatment with copper and/or aluminum compounds in the southernmost part of the pond can be used to maintain water clarity in the Town swimming area, and the existing circulation system will provide limited but beneficial mixing in that area. Water purification through natural soil filtration and active treatment upon withdrawal from the wells will facilitate a continued supply of safe drinking water, although treatment costs may increase over time. Overall, however, recreational utility and habitat quality can be expected to decline as the northern basin continues to fill in over the next 20 years and algal blooms become more frequent and possibly more severe in the southern basin. Continued high density of invasive rooted plants will impair swimming and boating uses away from the Town beach and diminish visual enjoyment of Morses Pond.

Evaluation of Management Options to Achieve Use Goals

A wide variety of techniques for managing algae/water clarity and rooted plant composition/biomass have been reviewed and applicability to Morses Pond has been evaluated.

In order to support the desired uses of Morses Pond, the following technical objectives must be achieved by the accumulated actions of a successful management plan:

1. Reduce the average phosphorus loading and concentration by 33% to achieve an in-lake average phosphorus level of 20 ppb, visibility of 4 ft visibility at all times and >6 ft visibility most of the time.

2. Eliminate invading, non-native, nuisance plant species to the extent possible, at least reducing them to a minor component of the plant community.

3. Reduce plant bottom cover and overall plant biomass by approximately 50% in areas <10 ft deep, eliminating interference with swimming and boating.

4. All actions taken must comply with existing Town policies, specifically the Integrated Pest Management (IPM) Policy.

Water Quality Improvement

Controlling algae and other suspended solids that affect water clarity is most effectively accomplished by watershed management in the case of Morses Pond, with both pollutant source control and trapping as viable approaches from a technical perspective. The focus would be on storm water inputs in this watershed. In lake methods will constitute maintenance in this case, with repeated application necessary. Evaluated methods for achieving the water clarity goal include:

¨ Watershed resident education – education is essential to minimizing inputs from developed areas and for gaining support for overall management efforts.

¨ Altered bylaws and regulations – existing bylaws should limit increased impact from developed areas, but supplemental regulatory actions targeting storm water management are needed to achieve desired loading reductions.

¨ Widespread localized storm water management through on-site, low impact techniques – localized controls will require an extended implementation period and active support, but has the potential to achieve desired contaminant control.

¨ Development of larger, upstream detention facilities – holding storm water for both natural purification and flood control is desirable, and detention could also involve actively treating the storm water, but both are expensive and difficult to implement in this watershed.

¨ Storm water treatment – aluminum compounds appear to offer the greatest potential to achieve the desired level of control; treatment in the northern basin of the pond could be very effective.

¨ Dredging - dredging of at least the northern basin is needed to restore the detention capacity of that area and to support the alum treatment over an extended period of years; additional dredging beyond the northern basin could also be beneficial, but the high cost is not justified solely for improved detention in Morses Pond.

¨ Mixing – circulation strategies could reduce blue-green algal scums, but will not control phosphorus and suspended solids to the desired level.

¨ Algaecides – directly killing algae remains a management option, but it is preferable to control the nutrients that fuel algal growth.

¨ Periodic alum treatments beyond the northern basin – lakewide treatment could maximize water clarity during summer, but would be less efficient than treatment near the point of entry (e.g., the northern basin).

¨ Biomanipulation - enhanced grazing on algae by fostering a more abundant population of larger zooplankton is desirable but not practical before the plant community is managed at a much lower density.

¨ Wetlands creation – use of wetlands in and around the northern basin could enhance water quality in the rest of the pond, but a thorough dredging of the northern basin to maximize detention capacity is preferred.

Rooted Plant Control

Control of rooted plants can be accomplished by several means, and it may require multiple techniques to address the suite of introduced and native nuisance species in Morses Pond. In-lake action is necessary because past inputs will support plant growths independent of any watershed management. Evaluated methods for achieving the plant biomass control goal include:

¨ Mechanical Harvesting – mechanical cutting and removal of plant biomass could provide the desired level of control, and might shift the community toward a more desirable mix of species over time if conducted carefully over multiple years with equipment capable of addressing all target areas in an appropriately rapid amount of time.

¨ Hand harvesting – although impractical at the scale necessary to control rooted plants throughout Morses Pond, selectively pulling out unwanted plants can be a valuable local control technique to prevent infestation of new nuisance species or maintain control once achieved by other methods.

¨ Benthic barriers - although too expensive at the scale necessary to control rooted plants throughout Morses Pond, covering small patches of unwanted plants can be a valuable local control technique.

¨ Hydroraking - although too expensive and disruptive at the scale necessary to control rooted plants throughout Morses Pond, selective hydroraking can provide plant control and debris removal in heavily used recreation areas.

¨ Herbicide application - the herbicide fluridone is most applicable to Morses Pond, and can be used in water supplies, but current Natural Resource Commission IPM policy prohibits the use of herbicides in Morses Pond at this time.

¨ Dredging – removal of sediment would remove plants and their root systems, seed beds and accumulated sediment, effectively setting the pond back in time, but at great cost and with limited control over later regrowth, which is likely to be substantial and could involve undesirable invasive species without continued management by other techniques.

¨ Drawdown – reduction in water level is expected to have serious negative impacts on the water supply and is not appropriate for Morses Pond.

¨ Biocontrol agents - grass carp are illegal for use in Massachusetts lakes and the milfoil weevil will attack only one of many problem species in Morses Pond; there is a beetle that is applicable to the emergent invasive purple loosestrife, but control of this wetland plant is considered peripheral to this management plan.

Permitting for management actions for the improvement of Morses Pond consists mainly of approval under the Wetlands Protection Act and Wellesley Wetlands Bylaw. Additional permitting processes apply for dredging and any chemical additions to the pond. Rejection or modification of projects through relevant permitting processes is possible, and recommended actions should be crafted to be acceptable under existing regulations. However, nearly all recommended actions have been permitted for Morses Pond in the past.

Recommended Management Program

Most of the current management actions have merit for maintaining uses of Morses Pond, but additional actions are needed to completely achieve use goals, and may reduce or eliminate the need for some current management activities. Recommended management actions intended to meet use goals include:

1. Professional Lake Manager Assistance – Retain the services of a professional lake manager to oversee and coordinate all core management activities. This represents a commitment to getting knowledgeable leadership for the preparation of requests for proposals, bid evaluation, activity scheduling, grant applications, budget and technical planning support, data evaluation, and program coordination and adjustment. The Lake Manager would not have to be a Town employee, but would have a clear commitment to the management of Morses Pond with possible extension to other Town ponds and would devote a set amount of time per year to associated tasks as laid out in a contract. The Lake Manager would report to a designated supervisor and would communicate regularly with all interested Town boards and commissions. The cost over a 5 year period is projected at $230,000.

B. Algae and Water Clarity Control:

1. Phosphorus and Sediment Inactivation - Install a buffered alum dosing station serving the northern basin (Area 1 in the accompanying figure, listed as Figure 3 of this report) and operate it from May through June, with possible use in July and August as warranted. Target storm events to get a reduction in phosphorus concentration and suspended solids (including algae, sediment, and even bacteria) that meets water clarity goals. Monitor phosphorus and turbidity on a weekly basis while the system is in operation. Monitor the build-up of settled material in the northern basin on an annual basis. The total cost over a 5 year period is estimated at $312,000.

2. Northern Basin Dredging – Hydraulically dredge the northern basin (Area 1). Remove all soft sediment and some additional material to maximize detention, targeting 20,000 cy of sediment. Coagulate and belt press the removed material to minimize the containment area needs, most likely working near the beach complex between early September and late November. Ultimate disposal location is to be determined, but material has beneficial uses and is not a large quantity by construction standards. Conduct this dredging after at least two years of monitoring of the alum treatment system, to allow determination of the accumulation of solids relating to alum application and any necessary adjustments to protect the investment represented by dredging. The total cost over a 5 year period is expected to be $650,000.

3. Watershed Education – Conduct an ongoing education program, utilizing the Education Coordinator currently supported by the Town, with a focus on reducing loading of pollutants from residential areas of the watershed, shown in the accompanying figure (Figure 2 from this report). Emphasize the need to infiltrate precipitation into the ground rather than allowing runoff to occur, providing background on low impact runoff control techniques that property owners can employ. Also stress the lack of a need for phosphorus in fertilizers for established lawns and the need to contain yard wastes. Create a website and a supporting brochure, and generate media coverage of the effort. Populate the website with interactive information about the best approaches for minimizing the impacts of urbanization on water resources in general and Morses Pond specifically. Utilize this website as a resource for teaching watershed residents, supporting information needs for desirable property management and addressing issues, questions and concerns by property owners. The website can also serve as a resource for education in the school system. Costs may be internalized to some degree, but estimates for outside assistance are provided here. The total cost over a 5 year period is projected at $110,200.

4. Review and Development of Land Management Bylaws – Perform a thorough review of existing Town bylaws and related regulations (including state and federal statutes) to determine where improvements are needed to more adequately protect Morses Pond. Develop improved or new bylaws to meet protection needs and support other management efforts such as Low Impact Development. Enhancements may include application of existing rules or policies on a smaller scale (e.g., to all parcels, not just those above certain thresholds) or development of new bylaws to address problems associated with new construction (e.g., limiting impervious surface area). Assist the Town in moving any new or revised bylaws through the approval process. The total cost over a 5 year period is expected to be $75,000.

5. Low Impact Development Program - Implement Low Impact Development techniques on new and existing residential sites. Build on the education program that informs residents of the need and opportunities for storm water management, providing support and incentives to manage storm water. Conduct demonstration projects on Town property in various locations to showcase this approach. Support private application with technical advice, design support and monitoring assistance. Encourage adoption of this approach in Natick and Weston as well. The total cost to the Town over a 5 year period is estimated at $142,000; private costs in excess of $1,000,000 are expected and extension to Weston and Natick is advised.

C. Rooted Plant Biomass Control:

1. Enhanced Mechanical Harvesting – Purchase harvesting equipment capable of harvesting plants over a 41-acre area in under 5 weeks and commit to the labor necessary to aggressively harvest in Areas 2, 3, 4 and 6 for 4 months per year. Harvest from mid-May through June, after which the harvester can be used in other ponds (if the expected level of control is achieved) until mid-August, when harvesting in Morses Pond would resume through mid-September. Gradually shift the focus from overall plant biomass reduction to control of nuisance species with encouragement of desirable species. Monitor plants at established locations on an annual basis in September. Consider installing a floating plant fragment barrier around major harvesting areas or the Town swimming area if fragment entry to the swimming area is unacceptably high. The total cost over a 5 year period is estimated at $553,200.

2. Manual Harvesting and Benthic Barrier Placement – Continue the water chestnut harvesting program, which has been a volunteer effort, providing equipment to enhance efficiency and comfort for the volunteers as warranted. Encourage shoreline residents to manage weeds in shallow areas not accessible to the mechanical harvester and around docks and other structures where the harvester cannot work effectively. Such management would involve hand pulling or manually raking plants in <2 feet of water and applying benthic barrier around docks or other structures as needed to supplement control by harvesting. Facilitate acquisition of a permit under the Wetlands Protection Act to allow all interested shoreline residents who would like to apply these techniques to do so. The total cost to the Town over a 5 year period is estimated at $19,100; up to $180,000 might be spent by private users, although much of the labor might be by volunteers

3. Selective Planting – It is likely that desirable native species will not colonize and become dominant in response to any plant control technique fast enough to provide maximum limitation of nuisance species invasion. While several years of rooted plant management and monitoring should be conducted before proceeding with any plant introduction, the active addition of desirable species through planting should be considered. Planting programs are still somewhat experimental and methods are under development and refinement. Assume an actual planting cost of $10,000 per acre, based on recent programs, with Areas 2 and 4 (15 acres) as the likely initial targets. The total cost over a 5 year period is projected at $170,000.

Application of this program over a 5 year period will allow phasing of core elements, evaluation of overall success and fine tuning for the future. Ongoing management expenses are to be expected, but will be reduced after the initial 5 year period. The accompanying table, which is also Table 6 from the Recommendations section of this report, outlines the costs and general timeline for expenses over a 5 year period. Additional considerations and details are included in the implementation table that follows it (Table 8 from this report). The total 5 year expense is estimated at almost $2.3 million and is expected to eliminate most current management costs for Morses Pond, estimated at $130,000 for that same 5 year period. Continuation of the recommended program for another 15 years beyond the initial 5 year period described above is projected to cost an additional $2.4 million. Supplemental management options, to be considered only if needs are not met by the core elements, have been identified for possible implementation over a hypothetical period of 5 to 8 years, but these options may not be needed at all, some options are mutually exclusive, and the timing of application is flexible and will affect costs. Projecting management needs and expenses beyond 5 years is very speculative and should be subject to review and revision as the program proceeds. A 5 year program at a cost of $2.3 million is therefore recommended.

This recommended management plan will enable the Town to meet the stated goals for Morses Pond within the context of stated priorities and will allow progress to be measured against clear plan objectives.

Morses Pond Watershed

Morses Pond Core Management Plan Elements, Five Year Plan, Timeline and Cost