Watershed Planning

APC & Nemasket River Watershed Management and Climate Action Plan

The integrity of the Assawompset Ponds Complex (APC) and Nemasket River depends upon the quality of their surrounding watershed and managing our uses and impacts.

A Watershed Management Plan sets up priorities for implementing projects that improve the APC and Nemasket; a Climate Action Plan extends the strategies under consideration to meet future conditions.

A Watershed Management and Climate Action Plan for the APC and Nemasket River will lay out the key strategies for balancing the complementary, though sometimes competing, functions of the APC and Nemasket River, especially in the areas of water supply maintenance, floodwater management, stormwater infiltration, habitat enhancement, and recreational access.

Whereas a traditional watershed management plan would contextualize recommendations in current watershed conditions, the Climate Action Plan component will add in an evaluation of watershed needs based on anticipated future climate change scenarios.

The plan will be designed to incorporate problem statements, goals, strategies and benchmarks of success for both existing conditions and issues and anticipated climate conditions in 2050 (assuming a high emissions scenario). Plan recommendations will include engineered and nature-based solutions for near-term and long-term floodwater mitigation, improved water quality, and consistent water supply in the APC as climate change occurs.

Why the APC and Nemasket? And Why Now?

A Regionally Unique and Significant Resource

The APC and Nemasket River play numerous important roles for both the natural ecology and the people of southeastern Massachusetts. The APC is the state's largest natural pond system and is the drinking water source for approximately 250,000 people in the cities of New Bedford, Taunton, and portions of other nearby towns. It is a scenic residential and recreation area for pondside communities, spanning the towns of Lakeville, Middleborough, Rochester and Freetown. Water flows out of the Ponds through one principal outlet - the Nemasket River. The Nemasket is the longest herring run in the state of Massachusetts, with fish making an annual trip from Narragansett Bay, up the Taunton and Nemasket Rivers into their breeding grounds at the Ponds. It is a significant habitat area for fish, birds, wetland and mammal species - now including a resurgence of the loon population!

While the Nemasket and APC are precious in so many ways, the management challenge for this system becomes clear when we consider that water quality and flow are affected by land use throughout their combined 44,900-acre watershed area. In equal measure, the waters of the APC and Nemasket River can have some negative effects on surrounding communities during periods of flood and intense storms.

Bedford Street in Lakeville in an aerial image as it runs north to south along the edge of the Assawompset Pond Complex
An aerial view of the northern end of Long Pond and the eastern edge of Assawompset Pond, intersected by Route 105.
An image of a stakeholder engagement meeting where participants from the Assawompset Pond Complex Management Team give their input into top priorities in the watershed.
The APC Management Team identifies floodwater issues around the Assawompset Pond Complex and Nemasket River

Building on a Track Record of Historic and Recent Work

The need for better stewardship of the APC and Nemasket River, especially in the form of a watershed management plan, is widely articulated across local MVP priorities. The Freetown, Lakeville, and Middleborough MVP Plans all raise this stewardship need as a priority action item. In June 2019, Lakeville, Freetown and Rochester completed a  Regional MVP Addendum. The top environmental action listed is “Update the Assawompset Ponds Management Plan with respect to the MVP process and data; include pond levels, infrastructure, herring run, Long Pond issues, other chronic problems/issues.” This priority is especially relevant for the ponds complex as there are several stakeholders with an interest in managing water levels. The communities surrounding the ponds have a stake in flood abatement, while the water supplier entities have an interest in storing water for potential future drought conditions. This proposed Watershed Management and Climate Resilience plan can promote active management coordinated across stakeholder needs.

Pursuing a watershed management plan at this time also leverages recent work completed in the APC and Nemasket watersheds. In early 2020, a grant from the Division of Ecological Restoration allowed for a reexamination of recent plans, as well as historical studies, reports, and recommendations going back forty years to 1980. The watershed management plan comes as a next step after that effort, and will be informed by an on-going hydraulic and hydrological study of the upper Nemasket, a WMOST model being conducted for the watershed by the EPA to pinpoint possible nature based solutions for addressing climate impacts, and community engagement for solutions along the river.

Plan Development Tasks Breakdown

Task 1 - Steering Committee

The Assawompset Pond Complex Management Team is serving as the project Steering Committee, with additional membership from staff and officials from Lakeville, Taunton, New Bedford, and Rochester. The Steering Committee is indispensable to ensuring that the final plan recommendations are actionable and fit with local goals and priorities.

Task 3 - Data Collection and Synthesis

The data synthesis and collection portion of the project will take place in year one. A specific portion of the data collection effort will be aimed at gathering estimated climate change impacts on water and precipitation levels, habitat types, and other conditions in the APC. Data summaries will be brought into the content of public events, as well as the existing conditions and anticipated future climate conditions sections of the plan.

Task 5 - Write the Plan

In year one, the project team will write the existing conditions and anticipated climate impacts sections, as well as the problem statements for all of the plan’s thematic sections. In year two, the project team will proceed to write the goals, action strategies, prioritization/implementation plan, and benchmarks of success sections, all informed by public community discussions.

Task 2 - Public Engagement

The public outreach component of the task will be divided into two phases: material preparation (project webpage, press releases, advertisements, material translation, meeting logistics) in year one and in-person events in year two. Conditions permitting, the year two public meetings will consist of six meetings that rotate between the six APC stakeholder communities.

Task 4 - Regulatory Review

A key method for promoting nature-based solutions to watershed management will involve understanding the regulatory frameworks, particularly in the four pondside communities, that either incentivize or prohibit low impact development strategies. In year one, the project team will focus on researching the regional operational standards and MOU’s. In year two, we will coordinate local bylaw reviews with the six thematic public workshop events.

A diagram of the two-year project timeline and its five task components

What Climate Change Impacts do we Expect in the watershed?

The most localized climate change predictions in Massachusetts are provided for the major watershed level at Resilient MA. The Nemasket River, Assawompset Pond, Pocksha Pond, and Long Pond are located in the Taunton River Watershed, while the Great Quittacas and Little Quittacas Ponds are located in the Buzzards Bay watershed. With the majority of the ponds area located in the Taunton, we use its figures in the data below. Observed changes are for Massachusetts as a whole.

Days over 90 Degrees

Observed: 

Predicted 2050: +15.2 to 33.5 days

Annual Rainfall

Observed:

Predicted 2050: +2.56" (spring/winter)

Extreme Weather Events

Observed (since 1958): 55% more heavy precipitation events

Predicted 2050:     +2 days of extreme weather per year

Number of Consecutive Dry Days

Observed:

Predicted 2050: +1.25 days (summer/fall)

Effects on Herring Migration

Predicted: Shorter run season, with all fish moving closer in time, causing bottlenecks at fish ladders that may turn fish away.

Plan Area Map viewer

The Watershed Boundaries

Explore the landscape of the APC and Nemasket River watershed area. The following map includes datasets that are already known, such as protected open space, ownership, wetland areas, and the like. This map will be updated as the project advances with layers that are created by the project team, where these layers assist in developing action item recommendations.

It's your watershed - please participate!

The Management and Climate Action Plan is to be a collective balancing of objectives across the dimensions of water quality and supply, habitat, recreation, and flood management.

 

We rely on you, APC community stakeholders across Lakeville, Middleborough, Taunton, New Bedford, Rochester, and Freetown, as our indispensable project partners.

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