Urban soil erosion is taking its toll, and a local conservation officer hopes a field day will help developers and city officials understand the importance of controlling measures.
Mary's Lake is paying a price for development, Doug Gahn says.
He should know. As a district conservationalist for the U.S. Department of Agriculture's Soil Conservation Service, he's been trained to spot soil erosion and sediment buildup -- problems he's seeing virtually in the back yard of his home at 2729 Harper.
"You can see piles of sediment, and you can see the surface area of Mary's Lake getting smaller and smaller," said Gahn, whose home is just north of the city-owned lake.
To call attention to problems at Mary's Lake and other spots in Douglas County, Gahn helped organize an event Thursday to showcase methods of stopping erosion and keeping sediment out of rivers, lakes and ponds.
"Kansas Urban Sediment Control Field Day" is scheduled Thursday at Yankee Tank Lake, just west of Lawrence off Clinton Parkway. Tours begin at 10 a.m. and 1:30 p.m.
Fifteen manufacturers will display more than 30 products and techniques, and organizers have obtained a rainfall simulator for field tests. Organizers expect the event, along with a seminar scheduled Wednesday, will draw 500 to 600 people to Lawrence.
Gahn said the field day was aimed at educating developers and city officials about the importance of controlling erosion and containing sediment at construction sites.
"It's been estimated that erosion in urban areas is 10 times higher than that on agricultural land," he said. "Part of that is because the topsoil, which contains the root masses, gets stripped. And there's a lot of compaction, so water doesn't soak in. And that causes runoff."
City officials have estimated it costs $25,000 a year to clean out storm sewers because of runoff from construction sites, he said.
Another organizer said although he didn't think erosion on city construction sites was a critical problem, the field day products could help local developers.
"Most of the urban construction that occurs locally has such a quick time frame that most of the applications that will be out there (at the field day) wouldn't be necessary in most projects," said Ron Durflinger, who represents the Lawrence Home Builders Assn. "But in some cases, I think they (builders) can benefit. If they've got a particularly steep grade situation where there's a lot of runoff, for instance, this will show them ways to manage that."
Gahn said owners of developed property also could benefit from the event.
"I hear about landowners in Lawrence who have a steep slope in their yard. They seed it, and their grass washes away, so they keep bringing in topsoil trying to get it established," he said. "This (field day) would show them products they could use to get around all that."