Onota Lake Invasive Species Management Plan
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Onota Lake Invasive Species Management Plan Prepared for: The City of Pittsfield By ENSR Corporation & Berkshire Regional Planning Commission Funding Provided by the Berkshire Regional Berkshire Environmental Fund Planning Commission City of Pittsfield Massachusetts Invasive Species Management Plan for Onota Lake ENSR Corporation and Berkshire Regional Planning Commission June 2005 1.0 INTRODUCTION ................................................................................................................................ 1-1 2.0 PAST AND CURRENT CONDITIONS .............................................................................................. 2-1 2.1 Lake and Watershed Setting .................................................................................................... 2-1 2.2 Basin Morphometry and Circulation ......................................................................................... 2-4 2.3 Temperature and Dissolved Oxygen Profiles .......................................................................... 2-4 2.4 Water Quality ............................................................................................................................ 2-7 2.5 Sediments ................................................................................................................................. 2-8 2.6 Plant communities .................................................................................................................... 2-8 2.7 Animal Communities ............................................................................................................... 2-10 2.8 Natural Heritage and Endangered Species ........................................................................... 2-13 3.0 PREVIOUS LAKE PLANNING AND MANAGEMENT EFFORTS .................................................. 3-1 3.1 Chronology of Lake Management Efforts ................................................................................ 3-2 3.2 Integrated Lake Goals of Onota Lake Long-Range Management Plan ................................. 3-6 4.0 AQUATIC VEGETATION MANAGEMENT TECHNIQUES ............................................................. 4-1 4.1 Candidate Aquatic Vegetation Control Options for Onota Lake ............................................. 4-1 4.2 Deciding Which Technique(s) to Apply .................................................................................... 4-2 5.0 ELEMENTS OF INVASIVE SPECIES MANAGEMENT PLAN FOR ONOTA LAKE .................... 5-1 5.1 Goals of Invasive Species Management Plan ......................................................................... 5-1 5.2 Aquatic Vegetation Management Plan Concerns/Comments from NHESP and MA DFW .. 5-2 6.0 RECOMMENDATIONS ...................................................................................................................... 6-1 6.1 Water Level Drawdown ............................................................................................................ 6-2 6.2 Herbicide Treatment ................................................................................................................. 6-7 6.3 Mechanical Harvesting / Hydroraking .................................................................................... 6-12 6.4 Biological Controls .................................................................................................................. 6-13 6.5 Hand-Harvesting ..................................................................................................................... 6-15 6.6 Benthic Barriers ...................................................................................................................... 6-16 7.0 ACTION PLAN ................................................................................................................................... 7-1 8.0 REFERENCES ................................................................................................................................... 8-1 Invasive Species Management Plan for Onota Lake June 2005 1.0 INTRODUCTION Onota Lake is a large waterbody located entirely within the City of Pittsfield in Berkshire County, Massachusetts. The lake is a local amenity and regional attraction for recreational uses such as swimming, fishing, and boating, as well as its designated uses such as supporting healthy aquatic life. These uses have been impacted by the extensive growth of aquatic vegetation, particularly the exotic invasive Eurasian watermilfoil (Myriophyllum spicatum) in the more shallow portions of the lake, particularly in the North Basin. A series of recommendations and management options for controlling this nuisance aquatic vegetative growth have evolved from rather extensive limnological and watershed investigations. Application of these vegetation management options have raised concerns regarding possible impacts to rare or endangered plant and animal species residing in the lake (MA DFW, 2004); resulting in a need for an comprehensive approach to aquatic vegetation management which is effective in reducing nuisance growth but protective of protected species. ENSR Corporation (ENSR) was selected by the City of Pittsfield for development, evaluation and refinement of an Invasive Species Management Plan for Onota Lake. Through this project, the City, the Lake Onota Preservation Association (LOPA), and the Berkshire Regional Planning Commission (BRPC) (acting as the administrator for this project on behalf of the City) will implement a critical recommendation of the Long Range Management Plan for Onota Lake, prepared by BRPC and LOPA for the City of Pittsfield in 2004. While the Onota management plan considers many aspects of watershed and lake management, a key recommendation (Management Goal #1) is to develop and implement a plan to protect and restore native aquatic plants and minimize the impacts of non-native, invasive plants (Pittsfield/BRPC/LOPA/BRPC/LOPA, 2004). Specifically, the comprehensive aquatic plant management is intended to: • maintain and improve healthy, native aquatic plants; • address the extent of the re-growth of milfoil in Onota Lake that is reaching nuisance levels for the current uses of the lake; • provide quality fish and wildlife habitat; • minimize the ecological and recreational impacts of nuisance aquatic plants; • effectively coordinates with other ongoing management efforts; and • address Onota Lake’s recent designation as rare and endangered species habitat. Invasive Species Management Plan for Onota Lake June 2005 1 -1 To achieve the aims of Management Goal #1, a Technical Advisory Group (TAG) was established to help create and refine the Invasive Species Management Plan and address potential concerns regarding protection of rare and endangered species habitat. The Technical Advisory Group is composed of experts in the fields of lake management (Dr. David Mitchell and Dr. Kenneth Wagner; ENSR International), aquatic botany (George Knocklein; Northeast Aquatic Research), ichthyology (Dr. Robert Schmidt; Simon’s Rock College), hydrology (Charles Steven Howe; ENSR Corporation), and environmental law (to be determined). ENSR is serving as the expert in lake management and has developed this initial Draft Invasive Species Management Plan for Onota Lake. ENSR reviewed existing data and relevant technical reports for Onota Lake provided by BRPC, as well as drawing on previous work conducted at the lake. In addition, ENSR considered experiences with past vegetation management techniques employed at Onota Lake. The Invasive Species Management Plan took into consideration the presence of rare and endangered species as determined by the Natural Heritage and Endangered Species Program. The initial draft plan and other relevant information was distributed to the Technical Advisory Group, who participated in a site visit to Onota Lake and a TAG Meeting at Springside Park House, Pittsfield MA on April 27, 2005 to review and critique the plan. BRPC revised the draft plan based on the site visit and TAG meeting discussions. BRPC submitted the revised Final Plan to ENSR and other TAG members for review and final approval. The BCRP Project Manager was Melissa Jette (413-442-1521 ext. 22; [email protected]). The TAG member and senior technical reviewer for ENSR were, respectively, Dr. Dave Mitchell (978- 589-3077; [email protected]) and Dr. Kenneth Wagner (860-429-5323; [email protected]). Following a similar approach to that adopted for the Long-Term Management Plan (Pittsfield/BRPC/LOPA, 2004), the Invasive Species Management Plan for Onota Lake will summarize to avoid duplication of material and maintain consistency with the relevant studies and policies. To the greatest extent possible the Plan will summarize and integrate the individual findings and recommendations of these existing documents. Invasive Species Management Plan for Onota Lake June 2005 1 -2 2.0 PAST AND CURRENT CONDITIONS This section provides an overview and summary of the current conditions in Lake Onota, particularly those that may be critical for aquatic vegetation control evaluation. Due to the rather extensive bibliography of work on Onota Lake, no attempt will be made to comprehensively report on each subject; rather a short summary is provided, with further detail and data available in the referenced source documents. Much of the material presented below is taken from the Long-Range Management Plan (Pittsfield/BRPC/LOPA, 2004), supplemented with findings from other studies. The Housatonic