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DNR to host April 7 open house to discuss repairs at Sweet Marsh impacting Martens Lake

  • 3/17/2022 3:57:00 PM
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TRIPOLI - The Iowa Department of Natural Resources (DNR) is hosting an open house to discuss a project to repair a portion of the dike network and the water control structure at Martens Lake on the Sweet Marsh Wildlife Area, on April 7, from 6-8 p.m., at the Tripoli City Hall, 303 S Main St., in Tripoli.

Martens Lake is part of a network of marshes and prairies that make up the 3,220-acre Sweet Marsh Wildlife Area, east of Tripoli. The area is popular for kayaking, bird watching, fishing and is a destination for waterfowl hunting.

A network of dikes is necessary to create and manage not only Martens Lake, but the refuge and other pools on the area. The project will repair more than two miles of the 70-year-old dike network, improve three miles of in-marsh channels used for boating access, remove sediment to create deep-water areas and fix the water control structure.

“Repairing the dike system will allow us to manage the water level in Martens Lake for the benefit of fish and wildlife, and improve public access,” said Jason Auel, wildlife biologist for the Iowa DNR. “We know this is a popular area and want to minimize the disruption for Martens Lake’s users. The goal is to only impact one season, but, as with construction projects, the work is weather dependent.”

The DNR will begin collecting and temporarily relocating fish from Martens Lake in late April-early May to segment A on the south end of Sweet Marsh. Martens Lake will begin dewatering around middle May, and anglers will have the opportunity to utilize the remaining fishery resource with relaxed fishing regulations from May 15 to June 15.

“We plan to open Martens Lake to liberalized fishing on May 15, which means that regulations on fish length and bag limits will be suspended and fish may be taken by a variety of methods,” said Dan Kirby, fisheries biologist with the Iowa DNR. Dynamite, poison, electric shocking devices, or any stupefying substances are not allowed, he said, and it is illegal to sell fish or stock captured fish into public waters.

“Iowa law does not allow fish to be transported away from Martens Lake in water, as a preventative measure to avoid spreading invasive aquatic species to other lakes, ponds, or rivers,” Kirby said.

In addition to repairing more than two miles of dike and improving three miles of in marsh channels, the contractor will use some of the sediment removed while creating the deep-water areas to recreate underwater humps that will revegetate during seasonal drawdowns providing vegetation to duck hunters.

Construction is scheduled to begin after Sept. 1 and conclude in spring 2023.

Martens Lake will begin refilling in the summer of 2023 and be restocked with fingerling bass and bluegill as well as some of the adult fish that were temporarily transferred to segment A.

Hunting and fishing on other segments of Sweet Marsh will still be available during the project. The contractor will operate out of the main parking lot, which may be closed to public access during the project.

Any person attending the open house and has special requirements, such as those related to mobility or hearing impairments, should contact the Iowa DNR or ADA Coordinator at 515-725-8200, Relay Iowa TTY Service 800-735-7942, or, and advise of specific needs.