. Community Development
City of Nashua Planning and Zoning
. - one Building Safety
Community Development Division Code Enforcement
: : Urban Programs
City Hall, 229 Main Street, PO Box 2019 Conservation Commission
Nashua, New Hampshire 03061-2019 Transportation
www.nashuanh.gov FAX
589-3095
589-3090
589-3080
589-3100
589-3085
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880-0100
589-3119
Date: March 24, 2021
To: John Griffin, CFO; Kim Kleiner, Administrative Services Director, Kelly Parkinson,
Purchasing Manager
From: Deb Chisholm, Waterways Manager
Re: Contract for Aquatic Invasive Species Control and Management
Nuisance aquatic invasive plants are present in multiple Nashua water bodies, most notably the
Nashua River upstream of Mine Falls dam, the Mill Pond and Nashua Canal. During summer
2017 the City also received several complaints regarding excessive plant growth in Sandy Pond
and the Waterways Manager documented that Curly Leaf Pondweed, an aquatic invasive species,
was present in this pond. Aquatic invasive weeds, such as milfoil, fanwort, and water chestnut,
can make rivers and ponds unsightly, recreation unpleasant, and navigation by boat difficult.
Furthermore, excessive growth of vegetation can impair water quality due to reduced dissolved
oxygen which can cause fish kills.
The City’s Waterways Manager works closely with the State Invasive Species Coordinator at
NH DES to monitor the presence and extent of invasive species and update the Long-term Exotic
Aquatic Plant Management Plan for our waterways.
The City has been involved in controlling aquatic invasive species since 2011 when action was
taken to control Water Chestnut by mechanical harvest. This was very effective at removing
Water Chestnut and we now can continue to control Water Chestnut by hand pulling with
volunteers. Unfortunately, the decline in Water Chestnut created an opportunity for other
invasive species present in the River to take over. The vegetation is now dominated by milfoil
and fanwort which cannot be mechanically harvested or hand pulled, leaving herbicide treatment
as the only recommended effective management strategy. Herbicide treatments in rivers and
ponds are closely regulated and permitted which involves extensive public notice.
During the summers of 2017, 2018, 2019 and 2020, herbicide treatments were used to control
milfoil and fanwort on 84 acres of the Nashua River upstream of the Mine Falls dam. This
resulted in a very noticeable improvement over 2016 conditions and we received multiple
messages from constituents reporting they were pleased with this outcome. Herbicide treatments
are recommended again this summer to continue reducing the coverage and extent of these
invasive species in this section of the Nashua River.
In response to complaints about the excessive plant and algae growth in Sandy Pond we will
continue taking action to control curly leaf pond weed and reduce nuisance algae to improve the
appearance and water quality of this pond.
Solitude Lake management is the only company in the region that provides this type of service,
and in accordance with the NH DES invasive species management grant program, we solicited a
