At its May 8 meeting, the Laurie Board of Aldermen approved another expenditure toward trying a new fix for its main water well.
The board green-lighted a $15,000 fee for its engineering firm, Bartlett & West, to oversee a project to extend the steel casing in Water Well 3. Located off of Route O, Well #3 is the largest source of water for the city, but has had intermittent problems with infiltration of sediment since it went online in 2001 with increasing frequency in these episodes of cloudiness since late 2009.
The plan is to extend the casing down another 150 feet in an attempt to block out the space where engineers believe the silt is entering the well. A previously done diagnostic video of the well shows an area of broken rock and silt material at this depth. Most of the water comes from deep within the well where the cut appears to be smoother, so extension would potentially seal the rough section out without affecting the water supply.
A rough estimate made in a recently completed master plan for the water system put the cost at approximately $50,000. If the city moves forward with the project, the proposal will be submitted to the Missouri Department of Natural Resources for a construction permit and for bid documents in a sealed bid process.
The project is not a guaranteed fix but neither is a new well, which could potentially have the same problem, Public Works Director Ed Young has said.
The board has previously attempted to fix the issue by having the pump lowered from 400 feet to 695 feet, but the move proved unsuccessful.
A turbidity sensor now shuts off the well from the system when cloudiness is detected, allowing the city to keep the water from coming out at users' taps.
In the master plan for the water system, the rehabilitation of Well #3 received the highest priority on the list of potential projects. Bartlett & West Engineering recommended the city install a lining in Well #3 below the current casing.
The city's only other working well is smaller with less pump capacity than Well #3. Well #2 (Well #1 is no longer operational) is capable of meeting the capacity of an average day, according to the engineers, but at peak flow would not be enough to meet the needs of the city. DNR also recommends redundancy in the source of water for greater reliability.
In the planning process, other solutions were considered for Well #3. Besides a new well, other options reviewed included filtering, interconnecting to another system, surface water treatment, section control and enlarging Well #2. The alternatives to the selected project were considered prohibitively expensive or not feasible.