With the exception of a few brave souls, many ducks and geese have long since waved goodbye to the state in favor of warmer haunts further south down the flyway.
However, to help prepare for their return north next spring, a construction project is underway at Sand Lake National Wildlife Refuge to build a new water-control structure. When finished, it will allow refuge managers more control over water levels in a 80-acre wetland near the Columbia Dam fishing area in the refuge’s southwest corner.
“We’re helping build the structure and repairing a berm so they can provide habitat for ducks, geese and other wetland wildlife,” said Steve Donovan, Ducks Unlimited’s manager of conservation programs in South Dakota. “We work with Sand Lake quite a bit on a variety of projects. They mentioned the current structure was nonfunctional, and we had some money available and were looking for a project to take on.”
Donovan said funding for the project also includes grant monies from the James River Water Development District and the North American Wetlands Conservation Act.
“The whole idea behind the control structure is to allow refuge staff to manage water levels,” Donovan said.
He said draining wetlands allows plants to grow that can’t germinate underwater, such as smartweed or barnyard grass, which is sometimes called wild millet. Ducks can then eat the seeds of those plants in late summer through fall when the wetland is flooded.
“Those are two pretty common species that grow when you draw down a wetland,” he said. “A lot of people asked why refuge staff let all the water out of the lake last year, but the proof was in the pudding last fall when it got flooded and saw swarms of ducks return. It’s important to grow some food instead of just cattails.”
Beyond ducks, improving wetland health has positive side effects for people up and down the Jim River.
“The James River Water Development District also got excited about it because it retains water holding capacity,” he said. “Wetlands have tremendous ability to improve water quality.”
Before building the new structure, the old one had to come out, said Maddie Saylor, Ducks Unlimited’s engineer for projects in South Dakota.
“There were two existing dilapidated, steel structures in need of replacement along an embankment separating the wetland impoundment from the James River,” she said. “Ducks Unlimited designed a concrete water-control structure featuring reinforced concrete pipe, a stop log channel, canal gate and rock riprap. The new structure will allow the U.S. Fish and Wildlife Service the ability to manage water levels in the wetland by means of gravity. The project is still under construction and is expected to be completed in February.”
Saylor said the structure’s concrete pipe was placed last week, and the concrete headwall was formed and poured on Jan. 23. Work will resume after a five-day drying period for the concrete.
The next step, Saylor said, is to put in the canal gate that will allow refuge staff to control water levels regardless of the current flow of the James River.
“When the river comes up, water can go in the wetland, and when the river goes down we’re putting in a culvert that connects to a vertical culvert with a gate in it that will regulate water levels in the unit,” she said. “This gives refuge staff control over the water levels in the wetland so they’re not so dependent on the water level of the river. This will let them draw the wetland down and promote germination of a natural seed bed in that unit.”
Right now, cattails are about the only thing found in the impoundment, Saylor said.
“It’s OK to have some cattails,” she said, “but now they’ll be able to draw it down early and wait until they get some smartweed or millet or whatever they want to grow in there.”
When looking at Sand Lake as a whole, which covers thousands of acres, it might seem trivial to worry about an 80-acre wetland. However, the added capacity to refine habitat management efforts, even on a small chunk of ground, has plenty of benefits.
“For the most part we’ll be able to fine-tune our management and provide more feed for migrating and staging waterfowl,” said Eric Hoggarth, a wildlife refuge specialist and federal wildlife officer from Sand Lake National Wildlife Refuge. “On Sand Lake itself, our ability to manipulate water is pretty limited — we’re at the mercy of drought or heavy rains. On this type of impoundment, even in a dry year we can get enough water to put in there.”
Hoggarth echoed Donovan’s statement that the number of waterfowl using the refuge last fall was emblematic of how ducks still flock to natural food such as smartweed.
“Ducks weren’t raised on corn years ago, and we can grow this stuff naturally with the right conditions,” Hoggarth said. “I bet we had a half-million ducks out here last fall from mid-September until we froze up in December solely due to water management and the amount of smartweed that came up from the lake bottom. On this small impoundment we can simulate the same thing more consistently.”
Hoggarth said once construction is complete refuge staff will use a moist-soil management strategy for the wetland, and the first order of business is prepping the wetland by dumping all the water, removing all the silt that’s accumulated over the years and eliminating unwanted plants, such as cattails, through prescribed burns.
“It’s not like Sand Lake needs more cattails,” he said. “We’re trying to provide other aquatic plants that feed migratory birds. A lot of the desirable plants we’re after, though, are annuals that often get choked out by perennials. The annuals produce the seeds ducks want, and when you have acres of these plants it equates to more ducks in the flyway and healthier hens on the nest.”
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