Presentation to May 21, 2016 NEC-NALMS/MACOLAP 2016 Marlborough, MA Carl Nielsen, CLM, Matt Ladewig, CLM, Jacki Amante, Mike Mahoney, Gordon Perkins Shoreline Erosion Are Those Ruts Really Impacting My Lake!?

Introduction The quality of water in every lake is a result of the nutrients it receives. “You are What you Eat” applies to lakes too.

Introduction Phosphorus Inputs are cycled through a system, sometimes over and over Once P is in the system you cannot simply eliminate the watershed inputs and expect the system to improve – there is a long time lag

Erosion Stormwater runoff is usually a major factor in transport of phosphorus to lakes Phosphorus also enters from direct precipitation and from groundwater as well as from internal recycling Shoreline erosion occurs as a result of stormwater runoff but also from wave action, tree weight, ice damage, and foot traffic The Problem of Erosion Lake George Lost Lake

Case Study – White Pond, Concord, MA No major storm flows to pond - small watershed - no tributaries Limited development - a kettle pond - “The lesser twin of Walden”

Shoreline Erosion – White Pond, Concord, MA Shoreline erosion identified as one likely source of nutrients. Assessed with “black box” FF storm sampler.

Nutrient Loading – White Pond, Concord, MA About 14% of total P load to lake was from just a few small erosion areas…predominantly associated with trails!

Shoreline Erosion – White Pond, Concord, MA Solutions Proposed Trail management – water bars, fencing, railings, trail relocation, trail closing Slope stabilization and restoration/revegetation Increased infiltration

Tree Damage – Flowering Pond, Newburyport, MA Another small watershed – in a state park – not developed Shoreline collapsing from large white pines on steep slopes that start to lean, accumulate snow, then fall into pond taking out large sections of bank Flowering Pond Solution - Cut leaning trees on steep banks, monitor and do preventative cutting before large trees begin to lean too far

Shoreline Erosion – Lost Lake/Knops Pond, Groton, MA Knops Pond is a essentially a kettle lake. While Lost Lake behaves like a more typical lake with stream flows and an outlet.

Lost Lake/Knops Pond has a variety of issues, but shoreline erosion was well documented in many places by volunteers. They used photos, GPS, maps and other simple tools to document and prioritize areas for remediation. Shoreline Erosion – Lost Lake/Knops Pond, Groton, MA

Solutions will vary, but erosion repairs with infiltration, revegetation of shoreline, improving trails, and homeowner education are now being advanced. Shoreline Erosion – Lost Lake/Knops Pond, Groton, MA The key to success in a situation like this can very well be dedicated and educated volunteers.

Shoreline Erosion – Walden Pond, Concord, MA No major storm flows to pond – small watershed – no tributaries – another kettle pond – super water quality

Shoreline Erosion – Walden Pond, Concord, MA Erosion a major issue due to numerous trails with heavy use Repairs not lasting to date resulting in constant maintenance to repair same sites over and over

Shoreline Erosion – Walden Pond, Concord, MA The first step was field assessment to document erosion issues and develop possible solutions DCR also wanted to start to document the rate of erosion over time to correlate this with changes in water quality

Shoreline Erosion – Walden Pond, Concord, MA To do this, we photographed the entire shoreline of the pond and permanent photo and pin stations were established

Long-term documentation – Walden Pond, Concord, MA

Solutions for Natural or Undeveloped Land Trees Manage before damage occurs Reconfigure Trails Eliminate trails that are prone to problems, work trails across land contours, use more switchbacks to limit long runs in any one direction where water can accelerate Develop better defined access points with erosion protection plans Encourage Infiltration Encourage natural buffer vegetation with temporary fencing Create depression areas with good drainage Monitor Monitor shoreline routinely for erosion so that it can be addressed before it worsens

Solutions BeforeAfter But NOT this…

Solutions for Developed Land

But What if You Already Have a Real Problem? No amount of watershed work will eliminate these conditions

To Sum Up Phosphorus is the key nutrient in most freshwater systems More developed and more impervious watersheds have greater problems since they have greater transport of phosphorus – accelerating eutrophication. Stopping or slowing transport of phosphorus to a lake from its watershed is the best approach to slowing the eutrophication process. Even small erosional areas from forested, protected, or “undeveloped land” can have significant impacts on certain lakes. Monitor and fix these spots before it is too late. Once a lake has phosphorus in it, the lake will have increased algae and/or weed growth and managing external and internal sources will be essential to improving conditions.

Thank You THANK YOU