PUBLICATIONS
Watershed Management Plan
The Eightmile River Watershed Management Plan was created as a part of the Eightmile River Wild & Scenic Study to establish recommended tools and strategies for ensuring the watershed ecosystem is protected and enhanced for generations to come. The plan was developed by the locally-led Eightmile River Wild & Scenic Study Committee with input from town land use commissions, local citizens, the state and other key stakeholders.
The Eightmile River Watershed Management Plan is a non-regulatory document, reflecting a partnership where local, state and federal interests all voluntarily agree to participate in its implementation and the realization of its purpose and goals.
Tier One Management Issues
The Management Plan has identified four tier one management issues with recommended tools. The tier one recommended tools are high priority items that have been identified as important to implement in the short-term to ensure protection of the outstanding resource values. The Eightmile River Management plan as well has a host of tier two management recommendations to be implemented over a longer time frame. The details of those recommendations can be found in the full management plan document.
It is important to note that the recommendations for local land use commissions are just that, recommendations. The management plan or the powers of a Wild & Scenic designation can not force a community to adopt the recommendations. The actual implementation of these recommendations will require all the traditional formal procedures the commissions must follow in considering and potentially adopting any new regulations, including public notice, public hearings, and commission deliberation prior to making a final determination.
Tier One Management Issues Include:
Habitat Fragmentation
The size of unfragmented habitat blocks directly affects the distribution of species, and is critical to maintaining biological diversity and ecosystem function. Habitat fragmentation occurs when a large region of habitat is split into a collection of smaller areas. Fragmentation can cause, among other things, changes in species diversity, composition, population size, and community function.
The Eightmile River Watershed currently is substantially unfragmented—26% of the unfragmented blocks are greater than 500 acres in size, 15% are greater than 1,000 acres in size and 5% are greater than 2,500 acres in size.
Recommended Management Tool: Open Space Conservation
- Work with willing private landowners on a voluntary basis to conserve important habitat areas.
- Identify remaining unfragmented habitat blocks as high priority for open space conservation in town planning documents such as the Plan of Conservation and Development and the Open Space Plan.
- Establish a land protection goal for each community and the watershed as a whole, and seek federal funding assistance for land protection as part of Wild & Scenic designation.
- Commit to working with other partners, such as local land trusts, the Nature Conservancy and the State to leverage resources and collaborate when opportunities arise to protect priority lands.
An analysis of potential change to habitat blocks can be viewed in the following three maps:
1) Existing habitat blocks and current buildings of the Eightmile River Watershed
2) Open Space with existing habitat blocks and current buildings in the Eightmile River Watershed
Increases in Impervious Surfaces
Impervious surfaces, including roofs, roads and parking lots, can affect the water quality and hydrology of a watershed. Impervious surfaces cause increases in polluted stormwater runoff, which can impact nutrient levels, temperature, bacterial load and heavy metals found in our streams and rivers. An impervious cover of as low as 4% has been shown to degrade aquatic life and habitat quality.
The Eightmile River Watershed is currently estimated to have approximately
3% impervious cover. This low level of imperviousness is a key reason
why the watershed is still an intact and functioning ecosystem. Various
scenarios of how the watershed could be developed suggest that impervious
cover could increase to over 11%—which would lead to a substantial
degradation of watershed health.
Recommended Management Tool: Set Maximum Allowable Impervious Cover
- Set a maximum impervious cover target of 10% for any local basin within the Eightmile River Watershed.
- Set a maximum impervious cover target of 4% for the Eightmile River Watershed as whole.
- Work with the Eightmile River Committee to assess current and potential future imperviousness in each local watershed, and determine the amount of impervious cover still possible to meet the local watershed limit.
- Develop an effective, appropriate and realistic tool to locally manage impervious cover and pursue the tool’s adoption within each community
An analysis of potential change in impervious cover can be viewed in the following two maps:
1)
Current Impervious Cover of the Eightmile River Watershed
2) Potential
Impervious Cover at Full Buildout of the Eightmile River Watershed
Stormwater Management
Stormwater runoff can have profound affects on water quality, hydrology, stream channel morphology, floodplain function, habitat quality and ecological function. Approximately one-quarter of Connecticut’s major rivers and streams are impaired, and do not meet Clean Water Act standards due to impacts from stormwater runoff. Fortunately, there are a variety of best management practices that can help communities effectively manage stormwater runoff and minimize these potential adverse affects.
Recommended Management Tools: Apply State-of-the-Art Approaches to Managing Stormwater Runoff
- Require the 2004 CT DEP Stormwater Quality Manual to be used as guidance for the design, implementation and maintenance of all new and existing stormwater systems in each community.
- Complete and implement a Stormwater Management Plan as described in the State’s General Permit for the Discharge of Stormwater from Small Municipal Separate Storm Sewer Systems.
- Adopt guidance from The University of Massachusetts for watercourse
crossings (e.g., bridges and culverts), an approach that is used by
the New England Region of the Army Corps of Engineers.
Riparian Corridor Protection
Riparian corridors are the lands adjacent to rivers and streams. They are the first line of defense for a river system, and protecting the riparian corridor is a critical first step towards ensuring the long-term quality of river and water resources. Activities in the riparian corridor that remove or alter the functionality of the natural, native vegetative cover can substantially degrade its ability to perform its many ecosystem functions. Riparian corridors:
- Preserve water quality by filtering sediment and other pollutants from runoff before entering a river, stream or shallow ground water.
- Protect streambanks from erosion by maintaining an intact root structure along the banks.
- Provide a storage area for flood waters.
- Provide food and habitat for fish and wildlife.
- Provide shade for rivers and streams to keep water temperature low and dissolved oxygen high.
Recommended Management Tool: River Protection Overlay Area
- An overlay area for all perennial streams and rivers in the watershed to protect and enhance the functions and values of the riparian corridor.
- 50 ft protection for small headwater streams.
- 100 ft protection on larger streams.
- Provides flexibility by respecting pre-existing uses and providing for uses consistent with protection of riparian corridor function.
NOTE: The effect of this protection
tool on property owners would be small. Only 5 % of all lands in the
watershed would be within the proposed overlay. Of that, 97% of the
overlay area is regulated by local Inland Wetlands Commissions as either
wetland or upland review area. This tool is sensitive to ensuring landowners
are not unduly burdened through its potential implementation.
Following are three maps that display the proposed overlay area and provide a comparison with the existing locations of wetlands and watercourse as well as the regulated upland review area already under the jurisdiction of the local inland wetlands and watercourses commissions.
1) Proposed River Protection Overlay Zone - Eightmile River Watershed
2) Wetlands and Watercourses - Eightmile River Watershed
3) Existing Municipal Upland Review Areas - Eightmile River Watershed
Tier Two Management Issues
Tier Two Tools were used to outline the long term direction and strategies for protecting the ORVs. This longer list of recommendations and guidance includes less detail than the Tier One issues but rounds out the protection framework necessary to preserve the Eightmile well into the future. These tools are meant to be advisory in nature and implemented at the discretion of each land use commission and participating organization.
Tier Two recommended tools are longer-term actions partners can make to further protect watershed resources. It is anticipated it will take 2-5 years to implement the majority of the tier two tools, again this will partially depend on the ability of the ERWSCC to support the partners in the tool implementation when needed.
Many of the tier two tools recommend establishing additional scientific baseline information and monitoring for the outstanding resource values. The indicator goals provided with each ORV often recommend a benchmark to measure quality, or level of potential impacts to quality, over time. This information is critical to the overall success of the plan and its ability to assess and document the level of protection and enhancement achieved through the plan’s implementation.
The tier two tools focus on other longer-term opportunities as well,
including: the ongoing need to provide land use decision makers with
current, accurate and scientifically sound information and technical
advice to help in their decision making processes; the use of voluntary
open space conservation to protect important values; and outreach and
education initiatives to important target audiences such as landowners,
school groups and land use commissions.
A more detailed summary of the overlay proposal can be found by clicking here.