Lake Wenatchee water quality
By Wendy Walsh
On October 25,2008, residents met with Chelan County officials to discuss the
concerns about deteriorating water quality on the Lake Wenatchee Shorelines.
Several issues were discussed as possible contributors to the increase of algae
and scum on beach rocks: Fish Pens, Septic tanks, and Siltation.
The discussion included recent testing around Fish Pens, which was found to be
well below significant levels concern for phosphorus, nitrogen and dissolved oxygen.
There seems to also, to be no significant evidence of septic pollution at this time. It was pointed out that most full time residents were on sewers, and the rest of the
homes weren’t used that much by vacation owners.
Siltation was not addressed by the professionals, but a slide showing algae on the South Shoreline showed evidence of siltation over the rocks. Algae needs nutrients to grow, and siltation is a major source.
Beach siltation and algae.
At my request, Rollie Schmitten, a Northshore resident took some photos of
siltation issues on my shoreline, which also shows algae and deterioration of water quality on the beach area.
I have had a cabin on the Northshore for over 40 years, and until the past 10
years, the beaches have been pristine in clarity. They also were home to many
freshwater Mussels (M. Falcata) which are an indicator species for good health
in water quality.
The mussels began dying off, and gradually the water became murky. The fish pens are right across from my cabin, so I thought it was pollutants from there.
Then I noticed the silt increasing, and realized it was from erosion of topsoils.
There has been a tremendous increase in home building around the lake, and I have noticed that there seem to be no regulations for handling topsoil. Most lots are
small, so all the vegetation is often removed for building purposes, and there are
no requirements to revegetate the lots.
The result of all this building is a tremendous increase in surface water runoff from
metal roofs and driveways. Many homeowners put in cement driveways rather
than gravel, which slows the runoff of water during storm events.
There has been a steady removal of significant trees along Northshore drive by
homebuilders. Trees and understory vegetation filter surface water runoff during
storm events. Removal of vegetation increases siltation.
The fire on Dirty Face also denuded the steep areas of vegetation, and the Forest
Service decided not to revegetate. A large mudslide came off Dirty Face on to Northshore drive during a storm event, and a delta of mud flowed into the Lake.
Cleared beach lot.
Siltation is definitely changing our lake shore ecosystem. The photos which I include here show one of the typical sources. An uplake property near my cabin
has been bulldozed and cleared, but no preventive measures are being taken to prevent the topsoil from entering the lake. There are no plans to build this
year, so the storm events will continue, all winter to cause significant erosion of the topsoil which then travels to my beach and beyond.
Topsoil eroded into the Lake.
When I brought up the issue of siltation at the meeting, there was interest, but
no solutions other than education of homeowners and builders.
There was a booklet called The Washington Lake Book given out to residents,
and it mentions all the causes of water quality deterioration. Siltation is a big
part of the problem. The solution is better building and vegetation practices.
A steep gravel driveway which prevents erosion.
There is a good source of gravel locally for driveways, and local nurseries to revegetate with trees and understory plants.
The Shoreline Master Program is in the process of being revised. It seems to me that one of the major subjects that should be addressed is how to prevent further
siltation from entering the lake. It is definitely a big problem, and as the photos show, it should be addressed by the government, the Natural Resources, and
the homebuilders, as well as all the residents.
Wendy Walsh, Northshore Drive