Over the past couple of weeks, the water customers of the Blair water system have noticed a high concentration of chlorine smell in their water.
This was caused by a couple of factors that impacted our source water, the Missouri River.
Early last week there was substantial rain in Blair and areas to the north all falling on frozen ground causing runoff into waterways instead of seeping into the ground as it usually does.
The melting and releasing of ice jams upstream on the Missouri River also added to the runoff which carried mud and other debris from waterways that eventually dumped into the Missouri River, causing the river Turbidity to increase significantly. Turbidity is the measurement of how dirty the river water is at any given time.
Before the rains, the river turbidity was in the 20 NTU range (Nephelometric Turbidity Unit NTU). After the rains, the turbidity increased to a peak of 420 NTU. This increase occurred in less than 24 hours.
The staff at the Blair Water Treatment Plant immediately started to make treatment adjustments to deal with the increase in turbidity. This treatment required the use of an increase in chemicals, including chlorine. This caused an undesirable taste and odor to the city’s water.
The water system was never in jeopardy of becoming unsafe but the increase in chemical used to treat the water was necessary to keep the city’s water system safe for our customers. The City tests weekly as required by the Nebraska Department of Environment and Energy (NDEE) and Environmental Protection Agency (EPA).
Currently the turbidity of the river water is back to normal, and the water plant is running in a near normal manner with normal chemical usage for water treatment.
Although we are back to near normal chemical use, the taste and odor will continue as it takes time to flush through all the storage reservoirs and water mains.
The City staff did an exceptional job in dealing this this challenge and should all be commended for their efforts to keep the Blair water system safe even through the challenges that were presented to them.
Going forward this will most likely repeat over the next couple of months as this problem occurs typically in late winter or early spring as the ground is not thawed and heavy rains will continue to runoff into waterways. Further, the large snowpack to the north of the city can also cause the same problems with the river water especially if there is a rapid warm up and melts the snow quickly.
-Al Schoemaker, director of public works
