Halfway through July, Chautauqua Lake is speckled with occasional patches of green algae, and anyone who swims in the lake knows the familiar tickle of seaweed. Older Chautauquans will look at that and tell stories of seeing the bottom of the lake on a clear day. But John Jablonski said the lake is not greener on the other side of memory (although the seaweed was still there).

“The water in the lake this year is probably much clearer than it was 26 years ago,” he said.

Jablonski, executive director of the Chautauqua Watershed Conservancy, will lead a Bird, Tree & Garden Club Lake Walk at 6:30 p.m. Monday leaving from Heinz Beach. Becky Nystrom, a co-founder and board member for the conservancy, will also lend her expertise.

Together Jablonski and Nystrom will talk about the progress the conservancy has achieved since 1990, when he said it was largely a grassroots effort run from kitchen tables and living rooms. Now their efforts involve more than a thousand households, businesses and organizations working to preserve the lake’s ecosystem and maintain its water quality.

Jablonski said the conservancy’s first priority was securing certain areas of shoreline and wetland in collaboration with the New York Department of Environmental Conservation. That public-private partnership succeeded in preserving more than two miles of the lake’s approximately 40 miles of shoreline.

But less than 10 percent of Chautauqua Lake’s shore remains in its natural state, and almost all of it is privately owned. The focus, then, has been to teach homeowners basic stewardship, including why sandy beaches aren’t always ideal and why green lawns don’t belong everywhere.

The conservancy began mailing its newsletter — playfully titled “The ’Shed Sheet” — to every property owner for whom they had a mailing address in the mid-’90s. Now, that newsletter is distributed both physically and electronically with pertinent news and educational materials.

At the highest level, the conservancy and “The ’Shed Sheet” attempt to convince property owners to keep the shoreline natural, which mainly involves creating buffer zones of natural vegetation along the shore. Those zones absorb harmful nutrients from runoff that contribute to harmful algal blooms and unwanted aquatic plant growth (read: seaweed).

Those buffers can consist of flowering plants, such as milkweed, asters and goldenrod — all native plants that thrive in local conditions and support beneficial insects. Cattails and water lilies also provide a habitat for the lake’s whole ecosystem, Jablonski said.

Trees such as the black willow help out with deep, winding roots that grab onto the shore, protecting it from wave and ice action that erodes the shoreline. As proof, Jablonski pointed to areas of older black willows whose roots have formed small peninsulas along the shore, holding land in place.

If not for those trees, eroded materials flow into the lake, degrading the shore and contributing to sedimentation, the process by which sediments fill a body of water. Borne out to its extreme, sedimentation could fill in the already shallow Chautauqua Lake — by most estimates about 80 feet at its deepest.

But Jablonski said the conservancy stewardship efforts have been successful. Buffer zones are popping up all along the shore, particularly at Chautauqua Institution and even in communities such as Lakewood, which, until recently, had none at all.

“It’s really hard to get it going, but now it seems to have reached a critical mass where a lot of people are putting buffer in,” he said.

And even though Jablonski’s walk follows the shore, he said problems and solutions can be found upstream. He estimated almost three-fourths of the surrounding watershed, or the land area which drains into Chautauqua Lake, is covered by forest. Those trees serve as a natural filter that reduces or eliminates certain impurities in water as it flows to the lake. As development threatens forestland throughout the Chautauqua watershed, Jablonski said it’s important to maintain the area’s natural — and free — water treatment system.

Other than maintaining natural plant life, Jablonski said homeowners everywhere can minimize impervious surfaces like concrete sidewalks and patios that encourage unabated runoff. Consider removing a traditional lawn in favor of ground cover, or at least not fertilizing the lawn, as Jablonski said the phosphorus and nitrogen common in fertilizers flow into the lake.

The bottom line, Jablonski said, is to maintain robust and native plant life wherever possible so rainwater is absorbed and filtered before it reaches a major waterway.

“Maintaining as much of the natural vegetation and forest and wetlands in the watershed is what’s really going to dictate how well we maintain the water quality in the long run,” he said.