Lawrence's underground infrastructure has suffered significant damage from floodwaters, but the utility department's response has prevented serious public health risks so far, a state health official said Tuesday.
Howard Duncan, district environmentalist for the Kansas Department of Health and Environment, said Lawrence was among several cities in northeast Kansas that have been forced to discharge untreated or partially treated sewage and stormwater into nearby rivers.
None has created health hazards for the still-swollen Kansas River, he said. However, people should avoid the Kansas and Wakarusa rivers and stay out of drainage channels.
"People need to understand to avoid floodwaters in general," he said. "That does not mean that they have mysterious ... arms that grab you and consume you."
He praised the city's attention to the problems.
"It's not the kind of thing you do by choice. The response of the management has been proper," he said.
Roger Coffey, city utilities director, reported Friday that two collapsed sewer lines had allowed silt and clay to enter the city's wastewater treatment plant, hindering what's known as secondary treatment. Secondary treatment removes wastes with microbes and is more effective than primary treatment.
Primary treatment, which allows waste to gradually settle out of the water, continues at the plant.
Partially treated wastewater has been routed into the Wakarusa River through a drainage channel near 31st and Louisiana streets. Water being discharged into the Wakarusa meets quality standards, Coffey stated in a memo to the city manager's office.
Coffey said he expected "pretty good" progress today but could not estimate when repairs to the pipes would be complete.
Authorities continue to monitor water quality.
"We're being very guarded about things," Coffey said.
Coffey outlined other flood-related woes:
-- Sand drawn from the river continues to clog up the Kaw River Water Treatment Plant, but the plant is operational, Coffey said.
Both of the city's treatment plants are necessary to meet water demand, which has grown from 10 million gallons a day to 18.6 million gallons Monday. No conservation efforts have been imposed yet, Coffey said.
-- Algae invaded the Clinton Reservoir Water Treatment Plant on Sunday, making the water murky and affecting its acidity. The plant used a pre-chlorination treatment to solve the algae problem.
Pre-chlorination increases the likelihood of byproducts called trihalomethanes, which are regulated by the EPA. Coffey indicated that pre-chlorination should only last a few days.
-- Residents in the area surrounding 11th Street, east of Haskell Avenue, should continue boiling water used for drinking or cooking.