North Street re-opened Dec. 2 after Mansfield crews finished repairing a ruptured 30-inch sewer line that leaked into Walnut Creek.
The cost of containing the mess, making emergency repairs and installing a new pipe will run an estimated $250,000, said Jeff Price, assistant director of utilities.
The trouble started on Halloween when torrential rain eroded the ground near the sewer line, causing a support to break and the pipeline to rupture. Price estimates that nearly 900,000 gallons of sewage spewed into the creek. The 20-year-old pipe crosses a tributary of Walnut Creek, but it wasn’t designed as an aerial pipe.
Crews discovered the mess Nov. 3 while doing inspections, which are routine after Walnut Creek rises above flood stage. They initially estimated the spill at 1.8 million gallons but have since downgraded it.
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Workers plugged the leaky pipe, built a temporary bypass around it and worked to remediate the sewage in the creek. On Nov. 25, a new 30-inch pipe was installed. The new pipe will be armored with a steel casing.
“That will be an aerial crossing from now on because of the nature of the erosion that took place there,” he said.
Workers waited until the water pumps and other equipment were removed before opening North Street to traffic.
“We’ve done everything we could possibly do to prevent any kind of adverse effects resulting from the spill,” Price said.
The spill prompted Mansfield to cancel the Creekside Cleanup and Cookout event in November.