Why Peterson Ditch matters to Winona Lake

Peterson Ditch is a 13-mile inlet that The Watershed Foundation calls the largest contributor of sediment and phosphorus to Winona Lake. Of the four ditch systems traced on this site's watershed map, Peterson moves the most soil into the water, and with that soil the phosphorus that feeds the lake's algae. It is also the inlet with the clearest path to a fix: an engineering study of its streambanks was completed in 2025, and in July 2026 the Winona Lake Preservation Association received a $100,000 state grant for design-build work on the worst of the erosion.

This article covers where the ditch runs, why one inlet can account for so much of the lake's pollutant load, what the monitoring data shows, and what the funded projects are expected to keep out of the water.

Where Peterson Ditch runs

Winona Lake sits at the downstream end of an 18,730-acre watershed, a figure published by the Lilly Center for Lakes & Streams. Water reaches the lake through a handful of named channels. Wyland Ditch connects Sharon, Sheely, and Wyland lakes to Winona; Keefer-Evans Ditch flows north through Lake John; Tennant Ditch is a southeastern tributary near Tennant and Sellers lakes; and Peterson Ditch forms the southern branch of the system. Everything eventually leaves through a single outlet, Eagle Creek, which carries the lake's water onward to Walnut Creek and the Tippecanoe River.

Two boundary notes for map readers: the watershed page draws the federal Winona Lake–Eagle Creek subwatershed (HUC-12 051201060203 in the USGS Watershed Boundary Dataset), while the 18,730-acre figure comes from the Lilly Center's own delineation, and the two cover slightly different ground because delineation methods differ. Fourteen lakes sit inside that boundary, with Winona the largest and the farthest downstream.

Peterson Ditch drains agricultural and residential land south of the lake and enters Winona on the southwest side. Thirteen miles is a long run for a lake inlet, and every mile has a bank on each side. Those banks are where the sediment problem begins.

From eroding bank to algae in the lake

The chain has three links. Where a bank erodes, soil enters the water and travels downstream as sediment. That sediment carries nutrients along with it; the news release announcing the 2026 grant states that it "carries nutrients that cause algae blooms." Phosphorus travels with the soil, settles into the lake with it, and feeds algae growth from there.

Length and land use explain why Peterson tops the list. A 13-mile channel through farmland and neighborhoods has a great deal of erodible bank, and the land it drains sheds runoff that can pick up soil, fertilizer, grass clippings, pet waste, oil, and road salt on the way to the channel. That runoff rises sharply when it rains; what happens to Winona Lake after heavy rain covers that cycle in more detail.

What the monitoring shows

The Lilly Center samples 14 area streams every other week, all year round, including the water flowing into and out of Winona Lake. The parameter it publishes from those samples is E. coli, a bacteria count. Bacteria are a different problem from sediment or phosphorus, so the numbers below do not measure what the Peterson restoration work targets. They do show how differently the lake's inlets behave, which is the reason stream monitoring exists in the first place.

On that date, the water arriving through Peterson Ditch carried a bacteria count roughly ten times the threshold the Lilly Center's page cites, while the water leaving through Eagle Creek measured far below it. A single grab sample settles nothing by itself, but a gap that wide between one inlet and the outlet is exactly what biweekly sampling is designed to catch, and it is a reminder that the lake and the streams feeding it can be in very different shape on the same afternoon.

Between sampling dates, you can watch conditions on the inlet and outlet through a public stream monitor hosted on Xylem's HydroSphere platform.

The 2025 streambank stabilization study

Fixing a 13-mile ditch starts with finding out which parts of it are failing. The Watershed Foundation and the Winona Lake Preservation Association (WLPA), the volunteer nonprofit that has worked on the lake's behalf since the 1970s through invasive weed control and volunteer water-quality monitoring, brought in SWCA, an environmental consulting firm, for the Peterson Ditch Streambank Stabilization Study, with a funding goal of $40,600. Completed in 2025, the study identified the most erosion-prone areas along the ditch and produced designs for three high-impact restoration projects.

That groundwork turned a general concern into specific, buildable plans, and construction money followed within a year.

The 2026 LARE grant

In late July 2026, the Indiana DNR's Lake and River Enhancement (LARE) program awarded $203,000 in grants to three Kosciusko County lake associations partnering with The Watershed Foundation, according to a July 29, 2026 news release published by InkFreeNews. WLPA received $100,000 of that total to fund a design-build project addressing severe bank erosion on Peterson Ditch.

The release attaches numbers to both the problem and the fix. It estimates that Peterson Ditch contributes 74 tons of sediment to Winona Lake annually, and that this project will prevent an estimated 68 pounds of phosphorus and 78 pounds of nitrogen from reaching the lake. Sixty-eight pounds may sound small beside 74 tons, so the release offers scale: the three funded projects together are expected to keep 173.2 pounds of phosphorus per year out of area lakes, which it projects will prevent the growth of over 1.7 million pounds of wet weeds and algae.

LARE grants require at least a 20 percent local match, so local fundraising stays part of the picture even after an award. The program also has a long track record in this watershed: over 29 years, The Watershed Foundation has helped obtain 43 LARE grants totaling $1.8 million.

Lake Rx joins the funding picture

The Lilly Center is moving money toward this kind of work too. In April 2026, Grace College received a $10 million grant from Lilly Endowment to launch the Lilly Center's Lake Rx program, which turns the center's years of research into funded restoration projects; $2 million of the gift seeds the first on-the-ground and in-the-water work. Winona Lake is among Lake Rx's first partner lakes, and The Watershed Foundation is among its early collaborators, so Lake Rx support flows into the same local restoration effort that the Peterson Ditch project belongs to. With LARE covering $100,000 and every award needing a local match, having a research center that can also help fund the fix is a meaningful change for this watershed.

What residents can do

The construction phase belongs to WLPA, The Watershed Foundation, and their contractors. Residents shape the conditions around it.

• Support the organizations doing the work. The stewardship page lists the Winona Lake Preservation Association, The Watershed Foundation, and the Lilly Center, with links for donating and getting involved. Because every LARE award requires at least a 20 percent local match, money raised locally helps bring state money to the lake.
• Reduce runoff from your own property. Runoff can pick up soil, fertilizer, grass clippings, pet waste, oil, and road salt before it reaches a storm drain or ditch. Picking up after pets, keeping fertilizer and clippings off pavement, and planting a native buffer at the waterline all cut what a single lot contributes. The watershed page explains where each of those pollutants ends up.
• Watch the data. The Lilly Center posts stream results every other week, the live inlet and outlet monitor is public, and The Watershed Foundation's blog is where the Peterson Ditch updates have been posted so far. A project like this is easier to follow when you already know the baseline.

The short version

Peterson Ditch is Winona Lake's largest single source of sediment and phosphorus: a 13-mile channel that drains farm and residential land to the south and enters the lake on the southwest side. A 2025 study mapped its most erosion-prone banks and designed three restoration projects, and a $100,000 LARE grant awarded in July 2026 now funds design-build work expected to keep an estimated 68 pounds of phosphorus and 78 pounds of nitrogen out of the lake each year. To see how the ditch fits into the wider system, start with the watershed map and the rest of the lake maps, and check the Lilly Center's sampling pages when you want current numbers. The next milestone to watch is construction on the ditch itself.