What's the problem with Mariposa Lake?
The small 18-acre Mariposa Lake is threatened by excess sediment and nutrients, specifically phosphorous. High nutrient levels can lead to poor water quality and cloud the water, create low oxygen and high ammonia levels, which are harmful to fish and other aquatic life. These are not the only problems that excess sediment and nutrients cause though. It can lead to nuisance levels of algae and aquatic plants that interfere with recreation and can lead to potentially toxic algae blooms.
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What's being done to help Mariposa Lake?
The Mariposa Lake Watershed Project is working with local landowners to install conservation practices, primarily grassed waterways and terraces.

Grassed waterways in the 580-acre watershed are an effective practice in reducing soil erosion. These natural or constructed channels move surface water across the land without causing soil erosion. The vegetation in the waterway slows the water, protecting the land from rill and gully erosion.

Terraces are an efficient practice in reducing soil erosion and sediment in the Jasper County watershed. Terraces are built around a hillside and either slow runoff and guide it to the bottom of the hill or collect runoff and store it until the runoff can be absorbed by the ground. Terraces must be properly designed and maintained to combat erosion.

The project hopes to install a wetland that will be located above the lake. The wetland will help filter out nutrients, chemicals and sediment.
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What can I do to help?
Landowners in the Mariposa Lake watershed can improve the lake by partnering with the Mariposa Lake Watershed Project.

Dan Sorem, watershed project coordinator, can work with you to evaluate your property and identify practices that can help both the lake and your property. Sorem can also help find financial assistance to install those practices. Landowners participating in the watershed project can generally get improved financial assistance opportunities.

The Mariposa Lake Watershed Project is also looking for volunteers to help with streambank stabilization. Streambank stabilization involves protecting the streambanks of Mariposa Lake by using structures, such as rocks, and using vegetative measures.
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What is the future of Mariposa Lake?
"The future is good for Mariposa Lake and the watershed," said Mariposa Lake Watershed Coordinator Dan Sorem. "Continued conservation practices will allow visitors to Mariposa Lake to enjoy the facilities far into the future."
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Meet the project coordinator
Dan Sorem grew up in Garwin, Iowa and attended Iowa State University and majored in agronomy. Graduating in 2005, Sorem began work with soil and natural habits, soon becoming the Mariposa Lake Project Coordinator.

Sorem enjoys the ability to get outdoors and to deal with the local farmers that are looking to improve the watershed.

For other ways you can get involved with the Mariposa Lake Watershed Project, contact Dan Sorem, watershed coordinator, at (641)792-4116 or Dan.Sorem@ia.usda.gov
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Project partners

• Iowa DNR
• Iowa Department of Agriculture - Division of Soil Conservation
• USDA Natural Resources Conservation Service

For More Information
Local:
Dan Sorem
Mariposa Lake Watershed Project Coordinator
(641) 792-4116
Dan.Sorem@ia.usda.gov
Jasper County NRCS Office

Statewide:
Steve Hopkins
DNR Nonpoint Source Program Coordinator
(515) 281-6402
Stephen.Hopkins@dnr.iowa.gov