By Mark Pfost, Public Lands Ecologist – mpfost@wisducks.org
This article originally appeared in Wisconsin Waterfowl Association’s December, 2024 Newsletter edition.
You may recall that WWA finished its first public lands wetland restoration project with the DNR on Navarino Wildlife Area in late July. Spring and early summer this year were very wet. I worried that all the rain and subsequent high water levels would delay construction until late summer – if the rains ever quit and our site dried out. Rainfall dominated my conversations with the contractor as we approached the end of July, but he thought conditions would be okay and we agreed to get started.
On the day the contractor arrived on site, the ditch was full and flowing. Not only were we losing water, but constructing a solid ditch plug wasn’t feasible with a ditch full of water. He built a coffer dam west of the plug’s position to hold back water, and then pumped water out of the ditch for a day so that he could construct the plug without working in water.
While that work was going on, I went for a hike. My route paralleled the ditch on its south side, but well outside of the ditch corridor. A belt of trees, mostly buckthorn, and aspen, extended from the ditch bank to twenty yards or so away from it. I walked outside of this belt in restored tall-grass prairie. Even with all the recent rains, there was not standing water in my path — my boots stayed dry. Occasionally I noted a few sedges or a clump of wool grass — all wetland indicator species — but not a drop of water. Two days later, construction was completed and I sowed about eighty pounds of winter rye over the newly constructed plug and other disturbed areas.
After surveying another DNR site in early November, I detoured to Navarino to see how the restoration was looking. Little rain fell across much of Wisconsin from July to November, water levels in ditches and wetlands I drove past were low. I didn’t know what to expect. The first thing to catch my eye was how little the winter rye had grown. It appeared healthy but stunted — an indication of lack of rain since it was planted?
The second was that water in the ditch above the plug and water in the scrape built to construct the plug were much closer together now than when I last saw the site.
I walked the same path through the prairie again, but this time I was frequently walking in 4-6 inches of water – out nearly forty yards from the ditch. I circled the west end of the ditch, its origination point, and saw a pool wider than the ditch. I circled through a small one-acre patch of trees on the north side of the ditch (while getting bloodied by prickly ash) and observed numerous, scattered spots where water was beginning to pool within the trees.
Before and after, the ditch and the ditch plug—from the same point
The restoration still has room to “grow,” perhaps adding as much as another eighteen inches of depth near the plug. This increased depth, will also spread laterally, saturating soils further into the prairie and further into the forested area.
Water in ditch above plug (left) may soon merge with scrape (right).
Assuming more rains and a melting snowpack next spring, I anticipate visitors will observe more above-surface water, and at greater distances from the ditch, than I saw on my November walk. Increased water levels will eventually kill many trees and shrubs, transforming the site into a more open wetland.
Water expanding into prairie (left). Looking from above the point of origin of ditch; it’s now several times wider than before (right).
All indications point to a successful restoration.
This innovative public lands program is the result of an agreement with the Wisconsin Department of Natural Resources with Pittman-Robertson Funding derived from your hunting and fishing expenditures. Other funding necessary to support this program was contributed by the Fund For Lake Michigan, The James E. Dutton Foundation, and the Wisconsin Bird Fund, ” A Legacy Fund of the Society of the Tympanuchus Cupido Pinnatus.
