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Engineers share findings on well field capacity - Dec. 10, 2013

Barb Rayner
St. George
A study has determined the town can extract more water from two of its four wells.
Hydro-geologist of town engineers CBCL Limited Colin Walker told town council Monday night there is capacity for additional pumping under the current permit but there appears to be limited capacity to increase the pumping rate at two of the town’s four wells.
“What is the capacity of the well field? That is ultimately what will tell us how much water you can draw from the well field. We took all the information you had available,” he said as he went through the results of a desk-top study.
The total permitted pumping rate volume is 3,895 cubic metres per day but the average use is around 1,600, which Walker means the town could just about double its pumping rate.
He suggested the town use its additional available capacity before considering an increase to the permitted rates as well as consider well maintenance and rehabilitation as a means of increasing production rates.
“You should be paying close attention to the levels in the aquifer because the permitted rates are higher than what you are getting out of the wells so they could be affected by age.
“They could be clogged and one way to determine this would be downhole inspection. I think it is worth considering well maintenance to get production rates up to where they should be.”
Walker recommended establishing a monitoring program for water levels in the aquifer and conducting downhole camera inspections in two of the wells which can show whether the well screen has become clogged by minerals and/or slime forming bacteria.
Coun. Bruce Jackson said his concern was that if one of the wells was to be lost for some reason the town would be very pressed to provide enough water for the industrial park.
Works foreman Leonard Lee said the level in well No. 4, which is the town’s back-up well, has dropped three metres in the last year but Walker said, according to the tests carried out, it is capable of producing a lot of water.
“Maybe there is a lot of iron in the aquifer so there is a lot of cleaning you have to do to keep up production. If that doesn’t work, you are at a point where you need to find another well,” said Walker.
“I think you are at a point where you have to see if you can make the wells pump their permitted amount. Well No. 4 has the highest capacity so it should be able to cover any scenario.”
Jackson said the town is preparing its budget for 2014 so needed to know what it will cost to carry out the suggested well maintenance and Walker said it would be under $10,000.
Mayor Sharon Tucker commented that this presentation was very timely as the town contemplates its budget for the coming year.
barb@stcroixcourier.ca