Last weekend’s “do not use” order for tap water in Toledo, Ohio made national headlines
and has left many people wondering, could that happen here?
The short answer is it’s possible, but not likely.
Even if a harmful algal bloom were to impact water quality in our primary source of water (the Bushy Park Reservoir), we would switch to our secondary source, the Edisto River, which is not affected by algae blooms. Charleston Water System is fortunate to have two separate and abundant sources of water.
How does algae affect tap water?
Algae has long been a thorn in the side of utilities that rely on surface water sources, particularly lakes and reservoirs. Algae requires still water, sunlight, warm temperatures, and nutrients to thrive. In these conditions, algae cells can multiply quickly and result in an algal bloom.
There are many types of algae. Some species release toxic compounds when the algae cells die. Excessive growth of these toxin-producing algae are known as harmful algal blooms
. This is what happened in Lake Eerie, the source of drinking water for Toledo.
Has Charleston Water System ever had a harmful algal bloom?
Fortunately, no. But we have experienced a more common algae-related issue: Taste and odor problems.
The type of algae that occurs in Bushy Park isn’t harmful, but it can release compounds that have a distinctive, unpleasant earthy/musty taste and odor. These compounds (MIB
) are difficult to remove and may noticeably affect our water’s taste at very low levels (5 parts per trillion!).
These taste and odor problems tend to occur during the spring and summer, when conditions are ideal for algae growth. After a severe earthy-musty episode in 2012
, we improved the way we monitor for MIB and Geosmin in Bushy Park and installed a new powdered activated carbon system to better remove these “earthy” compounds.
For the long term, we’ve partnered with the US Geological Survey (USGS) to conduct a four-year study of the Bushy Park Reservoir. Now in its second year, this study will provide us with data on the conditions in the reservoir that affect algae growth and overall water quality. This data will provide us with information on which to base any long-term plans for protecting and improving water quality in Bushy Park.
Bushy Park Reservoir
Protecting sources of drinking water
The Toledo incident is a reminder of the importance of protecting sources of drinking water. One way everyone can help is by using fertilizer correctly. Excess nutrients from over-fertilizing can run off into surface water sources and contribute to the severity of algal blooms.