Island Renovation: Part I - Dyck Arboretum

During December Scott and I have been working on renovating and restoring the edges of the pond island. This beloved spot is where children like to feed the ducks and turtles, where couples get engagement pictures taken, and where visitors can spend a quiet moment near the water. Over the past 40 years it has eroded away in many places. Thanks to a grant from the Central Kansas Community Foundation and a generous anonymous matching donation, we are able to strengthen the island banks and keep it in good shape for years to come.

Rock Steady

The edges of the island were originally made of a redwood retaining wall, backfilled with rock and soil. While the redwood wall has stayed remarkably intact, the material behind it has eroded away. There was over a six foot gap in some places between where the bank used to be and where it is now! All that material has floated downstream during flood events and times of high flow. We are filling in these gaps with concrete and brick rubble.

First we added rock to fill the gap between the bank and the retaining wall. This gap was 3 to 6 feet in some places. Then we dumped and raked dirt over this rock to form a seed bed for grasses and wildflowers.

Adding Soil

On top of the rock goes 4-8 inches of soil. This area will be home to a continuation of the prairie grasses and forbs currently growing on the island. Switchgrass, dotted blazing star, and purple prairie clover are already growing well on the higher areas of the island. I hope prairie cordgrass, river oats and Kansas gayfeather will colonize lower portions of our new island edge in the coming years.

We will seed this area, as well as allow the neighboring plantings to spread naturally into it. Controlling invasive weeds here will be a high priority next spring and summer as this soil likely contains unfamiliar weed seeds, some of which may be noxious or highly invasive.

Out of Bounds

We are also dumping rubble on the outside of the redwood retaining board. This will help stop erosion, support the board in light of all the new weight being dumped behind it, and create a substrate for future aquatic plants. In spring that outer rock layer will become a substrate for planting new aquatic species. We hope to add hibiscus, lizards tail, equisetum, marsh marigold, pickerel weed, and other native pond plants.

The red line shows the wooden retaining wall. This was the original bank, and it has now been restored with rock and a layer of soil on top. By adding rock on the outside of that, we are able to strengthen it even more and hopefully create a useable substrate to hold future aquatic plantings.

Maintaining the grounds is a big job. The needed repairs never end, and it can get expensive. Donations, memberships, FloraKansas purchases, and all the other ways you support the Dyck Arboretum helps keep these acres safe and accessible to the community.

Thank you to all who gave to this pond renovation initiative. Keep your eyes peeled for future updates on the planting and growth of this new pond edge!