Camrose Raw Water Intake and Upgrade
The City of Camrose's existing raw water intake was a settling basin on the north shore of Driedmeat Lake south of Camrose. A raw water pump station drew water form the settling basin and pumped it to the water treatment plant in Camrose approximately 13 km away.
Freezing and Algae
The settling basin and two inlet pipes were subject to freezing and frazil ice in the winter and algae blooms in the summer. ISL was retained by the City in 2001 to design and construct a more robust and long-term solution in order to withdraw better quality raw water from deeper and further in the lake.
New Intake Structure
ISL designed a new intake structure to be constructed in the lake, as well as a 224-metre-long, 600 mm diameter HDPE pipe to connect to the raw water pump station. The structure was designed to allow for the installation of four intake pods, with room for two more in the future.
The intake structure and pods needed to be low profile because Driedmeat Lake is very shallow. The intake pods were shortened and increased to 855 mm in diameter to achieve the lowest possible profile. Three 2.4m x 1.2m steel plates were used to weigh down the intake without adding any height to the overall structure. Concrete collars were attached to the pipes that would settle into the silt on the lake bottom.
Construction was undertaken in the dead of winter. The trench for the pipe and intake was cut using chainsaws after thickening the ice to support the load of the pipe, concrete collars, intake pods, personnel and construction equipment. The construction of the intake on the ice allowed for the whole assembly to be assembled and lowered into position in a controlled fashion.
In 2015, ISL was retained to upgrade the raw water intake to support increased growth. The four existing pods were replaced with six half-circle pods with increased capacity. Due to foresight during the initial intake design, the replacement was quick and simple, conducted by professional divers while the intake was still in use.