P.O. Box 576 * 143 County Road * Ipswich, MA 01938 * 978-412-8200 * fax: 978-412-9100

P.O. Box 576

Ipswich, MA 01938

May 12, 2016 Board of Selectmen Ipswich Town Hall 25 Green Street. Ipswich, MA 01938 Dear members of the Board of Selectmen and Town Manager, I look forward to appearing before you at you May 16, 2016 meeting with Senior Town Planner Ethan Parsons to update you on the Ipswich Mills Dam Removal Feasibility Study. As you know, the town is partnering with us and the Massachusetts Division of Ecological Restoration through a federal grant to undertake the study which began a few weeks ago. Attached is some background on the project to prepare you for the meeting. In addition to updating you on the project before it goes public, a primary purpose of our meeting is to request your input on the scope of the initial public informational meeting about the project which will take place on June 8. We look forward to meeting with you on the 18th. Sincerely,

Wayne Castonguay Executive Director Attachment (1)

Ipswich Mills Dam Removal Feasibility Study

The Dam The Ipswich Mills Dam is a former mill dam located at the head of tide on the Ipswich River in downtown

Ipswich. The dam has been owned and operated by the Town of Ipswich since the 1980s when it was

acquired from Sylvania. The dam is categorized as a Significant Hazard Potential Dam by the MA Office

of Dam Safety. As of a 2009 inspection the dam was in Satisfactory condition (Haley & Aldrich Inc. 2009).

It is the farthest downstream of three dams on the Ipswich River and serves as the first barrier to

migratory fish as they move from the ocean into the Ipswich. The dam was retrofitted with a fish ladder

in 1995, but all ladders are inefficient at passing fish and some species will not use a ladder at all.

Rainbow smelt and American shad are two important migratory fish species that were historically

abundant in the Ipswich River and remain blocked from upstream access by the dam. In addition, the

dam blocks recreational uses of the river such as paddling and fishing in the downtown area.

History The dam and the surrounding area have a rich history

The dam is believed to be built on the site of a rocky ledge, the “upper falls”, that was used as a

ford for Native Americans and early settlers

c. 1637: First dam constructed at the site near the location of the “upper falls” of the Ipswich

River

The Dam was known for its role in powering hosiery production from the mid 19th to early 20th

centuries

c. 1908: The existing dam was constructed (or reconstructed) to provide power for adjacent mill

buildings

During the 20th century Sylvania manufactured light bulbs (and during WWII bomb fuses)

The mill buildings currently house EBSCO publishing.

Why Study Removal While the dam has a rich history and is aesthetically pleasing, it no longer serves the industrial purpose

for which it was constructed. As the owner, the Town is responsible for the ongoing costs and liability

associated with owning and maintaining the dam. Dam removal would permanently remove these costs

and risks. Considerable funding sources exist to help offset the short term costs associated with

removing a dam.

Environmental agencies and organizations including the MA Division of Ecological Restoration (DER),

National Marine Fisheries Service (NOAA Fisheries), and the Ipswich River Watershed Association (IRWA)

have had a strong interest in removing this dam for more than a decade due to its high ecological

restoration potential. The Ipswich Mills Dam ranks in the 90th percentile for the expected ecological

benefit of removal based on DER’s Restoration Potential Model. The Nature Conservancy ranked it in the

95th percentile for dams from Maine to Virginia (Martin & Apse 2011). Removing the dam would restore

access to 49 miles of river and stream habitat.

While there are clear ecological and long-term cost/liability benefits of removing a dam like the Ipswich

Mills Dam, there are many important considerations that can influence the cost and value of a project

like this. Important considerations including impacts on other infrastructure, historical and social value

and changes to existing ecological communities can greatly influence project cost and/or a final decision

on whether or not a restoration project is viable. Dam removal feasibility studies can help to quantify

the relative costs and benefits associated with a dam removal project and help a dam owner decide

whether or not to pursue removal.

Beginning in 2009, the Town has partnered with IRWA, DER, NOAA Fisheries and other partners on

studies to investigate the prospect of removing the dam. The goal of these studies has been to gain a

better understanding of the full range of benefits and costs associated with removing the dam so that

the Town can decide whether to pursue removing the structure or choose to maintain it as is.

Previous studies

2006: MA Riverways funded site reconnaissance study for this and the South Middleton Dam –

Identified Ipswich Mills dam removal as having substantial potential benefits to natural

resources and likely diminishing downstream flooding. Recommended further feasibility study

(Woodlot Alternatives Inc. 2006).

2014: Preliminary feasibility study. Ipswich Board of Selectmen voted to pursue funding for

preliminary feasibility study (Horsley Witten Group Inc. et al. 2014). This study found:

o The removal of the dam would lower the level of the water upstream of the dam such

that the water elevation likely would be governed by the rock ledge identified by IRWA

in a preliminary site survey extending approximately 10 feet upstream from the dam

structure;

o Dam removal would have no impact on downstream flooding and would decrease

upstream flooding; o The preliminary assessment of the dam environment suggests that there is a minimal

amount of sediment trapped by the dam and what little sediment exists is minimally

contaminated contamination and may not pose a threat to human or aquatic health;

o The lowering of the water elevation upstream of the site as a result of dam removal

could pose a biodeterioration threat to the foundation of the EBSCO building on the

river bank just upstream of the Ipswich Mills Dam if the building is supported by wooden

piles. Methods exist to mitigate these potential impacts. More information is required

to understand better the existing foundation structure and elevation.

2014: Bathymetric survey shows that post-removal water levels upstream of the dam may only

drop a few feet.

Current Study Based on the results of the studies referenced above, the Town and project partners decided to pursue

a full feasibility study with a goal of presenting Town officials with sufficient information to make a

decision as to whether to remove or retain the dam. The current study is funded by DER with support

from the National Fish and Wildlife Foundation (NFWF) grant that the Town provided a letter of support

for in 2014.

This study is underway now and will be taking place throughout 2016 and early 2017.

The scope of the current study includes:

Analysis and summary of the pre- and post- settlement history of the dam site and evaluation

of the historic value;

Detailed maps of existing conditions at the dam;

Hydrologic and hydraulic analysis of water levels and flows in a dam-out scenario considering

effects on flooding, effects of changes in upstream water levels, fish passage and ecology;

Investigation of EBSCO foundation to determine potential effects of dam removal on the

EBSCO building. Evaluate mitigation options if impacts are expected;

Evaluation of potential dam removal impacts to other structures;

Conceptual plans and cost estimates;

Conceptual renderings to show what we can expect the site to look like without the dam.

The Town and project team have planned an initial public meeting to discuss the project and hear

questions from interested citizens. The meeting will be held at Town Hall on Wednesday, June 8 at 7:00

PM. Representatives from the Technical Team will be on hand to discuss the project and take questions.

Literature cited Haley & Aldrich Inc., 2009. Ipswich Mills Dam Phase I Inspection/Evaluation,

Horsley Witten Group Inc., GEI Consultants Inc. & Clean Soils Environmental Ltd., 2014. Ipswich Mills Dam Partial Feasibility Study,

Martin, E.H. & Apse, C.D., 2011. Northeast Aquatic Connectivity: An Assessment of Dams on Northeastern Rivers,

Woodlot Alternatives Inc., 2006. Site Reconnaissance for Ipswich River Dams, Available at: http://ipswichriver.org/wp-content/uploads/2012/05/Site-Reconnaissance-Ipswich-River-Dams_Woodlot-Alt.pdf.