BELLINGHAM - The city is taking the first steps toward construction of a multimillion-dollar pre-treatment plant that will help prevent Lake Whatcom algae blooms from affecting the quality and quantity of the city's water supply.
Partly because of phosphorus-laden runoff from developed areas, the lake has had elevated levels of algae in recent years. In 2009, during an unusually warm summer, the algae concentrations became so high that they clogged the city's drinking water filtration system and reduced the water supply. That caused the city to impose mandatory watering restrictions to cope with a potential water shortage.
Although there has been no repeat of that crisis, the city still must treat the lake's water with disinfectants because of the algae, and that leaves small traces of potentially harmful chemicals in the water.
In 2014, the city will spend about $778,000 on preliminary design and other work on a pre-filtration system that will clear out most of the algae before it gets to the main treatment plant, reducing the need for chemicals and ending the threat of supply disruptions when lake conditions are bad.
The city, in cooperation with Whatcom County and the Lake Whatcom Water and Sewer District, is also trying to find ways of reducing the phosphorus in the lake, but that is a long and uncertain process, Public Works administrators say.
At a Monday, March 10, City Council committee meeting, Assistant Public Works Director Eric Johnston said CH2M Hill has been selected to perform preliminary work on the pre-filtration system that is expected to take up much of 2014. Design work will be done in 2015, with construction beginning in 2016.
With so much work yet to be done, cost estimates are approximate, but the price tag is expected to be between $15 million and $20 million, Johnston said.
He told the council that many cities, such as Anacortes, already have pre-filtration systems in place.
The cost of the new pre-filtration plant will be covered by revenue from city water bills. In late 2012, the council approved a series of increases that take effect at the start of each year between now and 2018, with the understanding that the increased water revenue was needed to pay for the pre-filtration and other water system improvements.
In January 2014, the flat monthly water rate for unmetered homes hit $35.27, up from $32.66 the previous year.
Unmetered city households pay that flat water rate of $35.27 per month no matter how much water they use, but the city is gradually converting all city residences to a metered system in which water bills will be partly based on the quantity of water used. Johnston said about 3,800 homes will be getting their first metered water bill in the next few weeks, and all homes are scheduled to be on meters by 2017.
For more details about the City of Bellingham water treatment program, go to cob.org/services/utilities/water.aspx.