Mariposa Park undergoing major restoration

The noise of birds was one of the few sounds heard Saturday at the Mariposa Recreation Area. The lake’s icy surface and snow on the muddy roads haven’t subsided yet, and efforts are underway to improve the park in dramatic ways.

An ongoing protection and improvement project is taking place at the man-made lake, built in 1952. Jasper County Conservation is partnering with the Iowa Department of Natural Resources to initiate a project to keep the 151-acre park looking refreshed and usable for many future generations.

JCC Director Keri Van Zante said the project is entirely funded through the DNR’s Iowa Lake Restoration Program. A lot of sediment has accumulated in the lake over its life span, decreased the surface area and depth and creating a visible water-quality problem.

Phosphorus attached to that sediment has led to blooms of algae, leading to poor water quality and clarity. These issues not only affect the appearance of the lake — which impacts how many tourism dollars are spent in the area — but also Mariposa’s aquatic life.

The 18-acre area houses a watershed of 580 acres, existing completely in northeast Jasper County. The Jasper County Conservation Board manages the lake. In 2013, the Jasper County Board of Supervisors approved Van Zante’s request to go ahead with the project, to be funded in three annual $200,000 allocations.

She told the board that a major wetlands project was completed in the year leading up to the request. Watershed work has been completed to reduce the amount of sediment and nutrients entering the lake, so the restoration is entering its final stages.

One goal is to restore Mariposa to its habitat as indicated on maps created in 1979.

The main components of the project will include:

• Dredging of the lake and design of a dredge spoil site.

• Removal and rebuilding of the main outlet structure.

• Renovating of the pond on west side of lake.

• Restoration of the function and native species composition of the wetland on the northeast tributary.

• Enhancement of in-lake fish habitat by adding rubble piles with trees and root wads, spawning beds, and catfish hides.

• Installation of shoreline stabilization to reduce wave action erosion, improve aesthetics, and help buffer against feces from loafing geese.

• Improvement of angler access and usability of the park and lake by adding a boat ramp, 3-4 truck/trailer parking spots, and fishing jetties.

Van Zante urges anglers and other users of the park to be patient, as it will take years to complete all of these improvements. Mariposa will remain open as much as possible, but it will take some time for the earthwork to be complete — and for the lake to refill itself.

Fishing is one of the main attractions at Mariposa, and regulations will be relaxed beginning April 1. Anglers will be allowed to harvest any size or number of all fish species from the lake until late summer, but a valid fishing license is still required. There are many picnic tables and a covered shelter available. The normal park hours of 5 a.m. until 10:30 p.m. will remain in effect. Any questions about the relaxed fishing regulations or the lake restoration project can be directed to Van Zante at 641-792-9780.

Contact Jason W. Brooks at 641-792-3121 ext. 6532 or jbrooks@newtondailynews.com