Merrimack River Revive

What Is the Merrimack River Revive?

The Merrimack River Revive (MRR) is a multi-year regional watershed project focused on flooding, stormwater, and water quality. The project uses shared data, hydrologic and hydraulic modeling, mapping, and community input to understand where flooding occurs, why it occurs, and how communities can work together to develop solutions.

The project builds on the work of the NMSC, which began as a stormwater-focused partnership that includes Billerica, Chelmsford, Dracut, Dunstable, Littleton, Lowell, Pepperell, Tewksbury, Tyngsborough, Westford, and Wilmington and has expanded to address broader flooding challenges across the watershed.

Who Is Involved?

The project brings together cities and towns in Northern Middlesex County, regional planners, technical experts, watershed organizations, and state partners. Working together allows communities with different resources and challenges to share information and plan solutions that work across town boundaries.

The towns of Andover, Billerica, Chelmsford, Dracut, Dunstable, the city of Lowell, the towns of Littleton, Pepperell, Tewksbury, Tyngsborough, Westford, and Wilmington, the Merrimack Watershed Council (MRWC), the Lowell Parks and Conservation Trust, and The Nature Conservancy (TNC).

Our regional approach is especially important because flooding and water-quality impacts do not stop at municipal boundaries.

Where Is the Project Focused?

The project focuses on the Merrimack River watershed in Northern Middlesex County. This includes rivers, streams, wetlands, neighborhoods, roads, and stormwater systems that drain into the Merrimack River.

Some areas experience flooding more often, while others may face greater risk in the future as rainfall increases.

Project Timeline

The Merrimack River Revive began in 2025 and is organized in phases:

• Phase 1 (2025): Stormwater infrastructure mapping and data standardization
• Phase 2 (2026–2027): Hydrologic and hydraulic modeling and analysis
• Future Phases: Planning and implementing solutions such as green infrastructure

Each phase builds on earlier work.

From Stormwater to Flooding Awareness

The NMSC was originally formed to support stormwater management and MS4 compliance. Over time, communities shared concerns about water quality, infrastructure, and flooding that went beyond stormwater systems alone.

The Merrimack River Revive reflects this broader focus by looking at flooding across the entire watershed, including rivers, drainage systems, land use, and climate impacts.

Equity and Environmental Justice

Flooding and water quality problems do not affect all communities the same way. Some neighborhoods face higher flood risk, fewer resources to recover, or greater impacts on health and safety.

The MRR includes equity considerations by:

• Looking at flooding risks in environmental justice (EJ) areas
• Identifying impacts near homes, schools, and critical facilities
• Supporting shared planning so smaller or lower-resourced communities can participate
• Using community input to better understand local concerns

Planning with equity in mind helps ensure solutions benefit the people most affected.

The project focuses on the Merrimack River watershed in Northern Middlesex County. This includes rivers, streams, wetlands, neighborhoods, roads, and stormwater systems that drain into the Merrimack River.

Some areas experience flooding more often, while others may face greater risk in the future as rainfall increases.

Hydrologic: How Water Moves Across the Land

Hydrologic work looks at how rain becomes runoff. This includes:

• How much rain falls
• Where water flows across streets, yards, and fields
• How land use affects runoff

Hydrologic analysis helps explain how much water enters the system.

Hydraulic: How Water Moves Through Pipes and Rivers

Hydraulic work looks at how water flows once it enters a river, culvert, or storm drain. This includes:

• Whether pipes and culverts are large enough
• Where water backs up or overflows
• How deep floodwater gets

Hydraulic analysis helps explain how water moves through the system.

Why Both Systems Matter

Flooding can happen when too much water enters the system or when the system cannot carry water away fast enough. The Merrimack River Revive uses hydrologic and hydraulic (H&H) modeling to understand both causes and plan better solutions.

Interactive Maps

The project will include public, easy-to-use online maps that show flooding risks, stormwater systems, and priority areas across the watershed.

Maps may include:

• How water flows across the watershed
• Flood-prone areas
• Storm drains, culverts, and outfalls
• Areas where flooding and equity concerns overlap
• Locations where green infrastructure could help

These tools support planning, grant applications, and public understanding.

Community Reporting Tool

Local knowledge helps improve maps and models. Residents and community members will be able to share flooding and water quality concerns using a simple online tool.

Users can:

• Choose a location on a map
• Describe what happens during storms
• Add details or photos (optional)

Community input helps ensure local experiences are reflected in regional planning.

Flooding affects safety, homes, roads, and water quality. Planning one town at a time can miss upstream and downstream connections.

The MRR helps communities:

• Plan together at the watershed scale
• Address flooding more equitably
• Improve both water quantity and water quality
• Protect the Merrimack River for future generations

Over the next two years, the project will:

• Complete hydrologic and hydraulic modeling
• Launch public maps and reporting tools
• Share findings with communities
• Identify priority projects and funding opportunities

Updates will be posted on this page as the project moves forward.