Sunday, 8 June 2014

Lake Repair

We constructed our first sizable Floating Treatment Wetland yesterday. It is a prototype grassroots bioremediation initiative.

Floating Treatment Wetland planted with bulrushes
The basic idea is very simple: Wetlands are nature's water filters. When you are unable to build a wetland due to shoreline erosion then it just makes sense to float it on the water.

My Aunt Shelagh and I have been playing with the idea for years. Last summer we made several models for testing and this winter we acquired several rotten wharfs from around the lake so we could start planting. 

The first Floating Treatment Wetland I built in August 2013. It was a mesh of willow branches that rooted into the lake.
We had an old wharf with trees growing out of it float by about 10 years ago. It was growing Alder trees out of the deck. Water bushes and moss were growing around the edges. It was a self contained eco system that provided habitat for birds fish and insects. We were always fascinated by the elegance of this floating island.

Our first constructed wetland was a happy accident. It was an old styrofoam box that floated a wharf. Someone had filled it with willow cuttings and let it free on the lake. We moored it up, not thinking much at the time and suddenly in spring it was sprouting roots and shoots.

First constructed Floating Wetland at sunset. We put solar lights on it so it would not be a hazard floating around.

Prototype Floating Treatment Wetland with potting soil.

We rearranged the willow and planted some bulrushes, mosses and ferns on to. It was a bit unstable; the dogs would step on it and both would flip into the lake and I would be diving for the plants and moss.

When we rebuilt our wharf we had four boxes filled with syrofoam left over. I quickly planted two with ferns, moss, grass and wildflowers. As an experiment I used potting soil on one of them and a rope to wick water up. On the other one I only laid down moss and planted into the styrofoam.

This was in early October 2013 so winter was coming. Luckily our local nursery, Dinter Nursery, had poly hoop houses that were the exact same width as the boxes. I used electrical staples to secure the metal rods to the wood so nothing would blow away in the winter storms.

Some days it was tropical inside the hoop house.
 The hoop houses contained a lot of the moisture so the floating gardens were acting like floating terrariums complete with a rain cycle. The evaporation cycle was enough to keep everything well watered.

The hoop houses kept everything warm over the winter, including one major snowfall. The sheltered environment allowed some wildflowers to bloom in January! They died back during the spring snowfall but it was impressive.

The gardens thrived over winter and I took off the hoop houses in April. The vegetation was lush and had a lot of species. The roots from the flowers are floating in the lake. The roots provide a home for bacteria that break down toxins in the water and consume excess nutrients.
Root system taking up nutrients and water from the lake.

 Unfortunately when I removed the hoop houses I removed the microclimate and it's rain cycle. As you can imagine the gardens turned into floating deserts without the water cycling around the enclosed greenhouse. The plants that were established in the lake had no issues so I have deep rooted flowers sprouting out of moss with no roots.

Flowers sprouting out of moss.
Over the spring of 2014 we acquired several derelict wharfs from around the lake and started planning. We knew what we needed to do, but didn't know how to get there.We played around with various ideas but never actually started work in earnest.

 In May 2014 we took a Permaculture Design Course at OUR Ecovillage and one of our instructors, Javan Kerby Bernakevitch issued the class a challenge to create a Permaculture project in no more than 10 days, with no more than 10 hours of work, and less than $100. We did ours in 8 hours with lots of cider breaks. We got some gas to go out to the ditch and dig bullrushes but besides that we used materials we had on hand. Another cost that could be factored in is $8.98 plus taxes on a roll of garden felt. I bought it for another project but used it for this instead so it was brand new.

We covered the styrofoam and boards with the felt. The previous owner of the wharf had already removed the deck so we had to balance along 2x4 boards or fall in the lake. After we stapled the felt in place we used a utility knife to cut out slits for our plants.Shelagh took a length of PVC pipe and a small sledge hammer to punch holes through the styrofoam. The pipe worked really well and contained nearly all the bits of foam inside the pipe.

Shelagh makes holes in the styrofoam

Various sized holes in the styrofoam
 The bulrushes slid right through the holes and the landscape fabric retains the mulch that we spread over the entire surface, The mulch keeps things in place, retains moisture (the wet in wetland) and we can grow other plants directly in the mulch. One of the issues on our lake is high nutrient loading so anything rooting into the lake is essentially growing hydroponically.

Planting the first bulrushes.Note the myceliated cardboard on the mulch.

After about an hour of leisurely work we had planted the whole thing and mulched it as well.  Our mulch had been sitting for a year and was completely infiltrated with mycelium. Hopefully we will have a strong mycelial mat form in the mulch. Mycelium are excellent water cleaners. The saprophytic fungi can break down hydrocarbons like motor oil which would be wonderful when all the power boats come out to play in summer time. 

 And here it is, our first intentional Floating Treatment Wetland on Shawnigan Lake.


  1. Hey Shelagh
    Can you tell me about placement of these floating treatment wetlands? Are they secured to anything? I am wondering because the Parks Commission has been concerned about random objects showing up on the lake creating a safety hazard (wakeboard jumps....) and also forgotten waste when no longer maintained (again, wakeboard jumps....) I'd like to promote this ideas and just want to have this concern eased as I spread the word and encourage it through the Parks Commission!

    1. Good question! Right now it is tied to our main wharf with two ropes.

      We have had a log boom for years, our spot on the lake is a collection zone for debris so we tend to accumulate logs, wharfs, boats, etc.

      Our attitude is that we are collecting and containing debris from the lake that would otherwise be liable to float freely. Our eventual plan is to contain our floating treatment wetlands behind a log boom breakwater which will create a containment area and nursery for immature floating wetlands.

      The head of the parks commission assisted us in collecting the old wharfs and this way he knows where they are and who to blame if one goes rogue.

  2. This is very proactive! I just hope "you " can now wnl the fight against the contaminated soil dumping!

  3. Thanks! Its been a community effort that has united the whole town and empowered some very special people in to collaborate in a way they never would have otherwise. Shemamma and I are doing our best to stay positive in these challenging times and prepare the solutions that are needed.