Lake Drawdown

An annual drawdown of 3ft is utilized at Onota Lake to protect against flooding during spring runoff, protect against shoreline destruction from ice, and to provide limited control of invasive species.  During the reconstruction of the Onota Lake dam in 1995, the 4-foot diameter outlet pipe previously in place was replaced with a 2-foot diameter pipe. This, inevitably, reduced the maximum outlet flow to twenty-five percent (25%) of the previous capacity, making it difficult to achieve drawdown within the ideal timeframe and climate. This problem was corrected in 2011 when a second two-foot diameter outlet pipe was added to the dam, restoring most of the original capacity.

Drawdown is a potentially effective means of controlling nuisance aquatic species within shallow areas of Onota Lake. Since nuisance plants such as E. watermilfoil, and Curlyleaf Pondweed are most problematic in shallower areas, this management technique may be particularly effective for the control of nuisance plants. An annual drawdown of 4 ft would be expected to reduce milfoil and curly-leaf pondweed cover over 257 acres of the lake. A drawdown of 8ft would be expected to increase the aquatic plant management area to over 324 acres of the total coverage area. (Wagner, 1996) The LOPA Drawdown Committee reviewed lake bathymetry and existing data in 2003. The committee estimated that an annual drawdown of 6ft would approximately double the aquatic plant management area and recommended periodic deep drawdowns. The City of Pittsfield has, for the past decade, followed a plan of yearly 3-foot drawdowns interspersed with targeted deeper drawdowns of 5.5-6 feet every 3 years. The city is currently preparing a new notice of intent to obtain a new permit to replace the current permit which expires at the end of 2018.



Fast Facts

Did you know that maximum lake speed is 45 mph?

For more information on Boater Safety see Boater Safety is Everyone’s Responsibility.

Did you know?

LOPA is an organization of volunteers. Our mission is to help the City of Pittsfield keep the lake clean and naturally beautiful for generations to come.

Why do a drawdown of the lake?

Lake drawdown is when the City of Pittsfield reduces the water level in the lake. Reasons: Shoreline erosion, weed management, flooding control.

How can I protect the Lake from Zebra Mussels?

Before launching a boat or kayak wash it thoroughly. Learn more about Zebra Mussels.

What You Can Do

Volunteer Opportunities

Beyond donations, there are many ways you can contribute to the preservation of Onota Lake. Here’s how you can help.


Become A Member

If you enjoy and appreciate Lake Onota, there’s a way you can give back. Becoming a LOPA Member means you support the preservation of this natural splendor.

Start Your Membership

What We Do

Our purpose is to assist the City of Pittsfield on all matters regarding Lake Onota. We’re a volunteer organization, providing education and scientific study to help preserve this beautiful place.

LOPA is the voice of Lake Onota, and our members are dedicated to its preservation and restoration.

Learn More About LOPA



Michael Riordan

Board Members

Lake Onota Preservation Association, Inc.
PO Box 2884
Pittsfield, MA 01202

City of Pittsfield

James McGrath
Park, Open Space, and Natural Resource Program Manager

Office of Community Development
City Hall
70 Allen Street
Pittsfield, MA 01201