Loveland: Algae bloom in Green Ridge Glade Reservoir update

Green Ridge Glade Reservoir
Green Ridge Glade Reservoir

From The City of Loveland (Gretchen Stanford):

I hear your concerns about the water quality and taste and odor issues we are experiencing in Loveland. My goal is to be as transparent as possible by sharing information about what is causing the taste and odor issues in Loveland and what Loveland Water and Power (LWP) is doing to resolve the problem.

Loveland has been abuzz for months about the unusually large, stubborn algae bloom at Green Ridge Glade Reservoir, one source of Loveland’s drinking water. Although this bloom is fierce, the drinking water in Loveland still meets federal regulatory requirements, plus even more-stringent state standards, for drinking water.

This algae bloom in particular is the largest we have ever seen. As a result of the 2013 flood, more nutrients have entered into runoff as it makes its way to our reservoir. The extreme heat and abundant sunshine we have had this summer developed into the perfect storm for an enormous algae bloom.

This bloom has revealed new algae species that reproduce more quickly and produce stronger geosmin, the compound that causes taste and odor issues. Additionally, the Big Thompson River is now afflicted with a significant level of the same algae. We cannot treat the free-flowing river water in the same way as we do the reservoir. And at this time, we are blending water from both the river and the reservoir at the Water Treatment Plant (WTP).

LWP water quality specialists are closely monitoring water quality by testing water samples at the Water Treatment Plant as well as at homes and businesses throughout the city on a daily basis. We are also treating the reservoir with a hydrogen peroxide-based algaecide that was developed as an environmentally safe alternative to copper-based algaecides. The only end-products of the treatment we use are oxygen and water. In addition, we are using a safe, absorbent activated-carbon compound inside the treatment plant to remove as much taste, odor and color from the water as possible.

Our technical staff continues to explore safe alternatives for treating algae blooms in the future while walking a thin line between the price tag of new technology and reasonable rates for our customers. Next week, LWP will begin a feasibility study to evaluate options for algae mitigation. The study will include permanent aeration or oxygenation system in the reservoir. We will also do a preliminary design of a larger system to store and dispense the activated carbon compound at the WTP. Unfortunately, those large capital costs are currently not budgeted.

While we would like to predict when the algae will die, it is important to note that algae is a living, unpredictable organism. Blooms usually end shortly after the first frost but we have no way to predict when that might be. We will continue to update our website http://www.cityofloveland/waterquality and Facebook page with timely information as we receive it.

The safety and quality of our drinking water is one of LWP’s most important goals. We recognize the vital role water plays in our daily lives. LWP takes water quality very seriously and will continue to produce safe, clean drinking water for our customers. We ask for your patience while we work to resolve this problem and find a way to prevent it in the future.

From The Fort Collins Coloradoan (Jacy Marmaduke):

An algae bloom in Green Ridge Glade Reservoir, the worst Loveland’s Water and Power division has experienced, is to blame for the unsavory taste and odor plaguing the city’s water supply. The blue-green algae is harmless, health-wise, according to state lab test results.

While the minuscule taste-and-odor compound released by the algae makes the taste disgusting, a lucky 25 percent of residents think the water’s fine because they can’t taste or smell the compound.

Soon, the other 75 percent of the city will have better-tasting water. The first hard freeze will mean a slow die-off of the algae bloom, water treatment manager Scott Dickmeyer said. After that, the water’s taste and smell should return to normal within a week or two.

But Loveland will have to invest in some new mitigation methods to keep the algae at bay.

Green Ridge Glade has always been susceptible to algae growth because it’s deep and relatively still. It’s not a recreation hub like Horsetooth Reservoir, from which Fort Collins gets its water, and water doesn’t flow in and out of it at a rapid rate like at Horsetooth because Loveland is its sole user.

So as temperatures rise, the reservoir’s deeper, stiller water produces nutrients that promote the growth of anabaena, a type of algae common in water systems.

Loveland officials use a hydrogen peroxide-based product to kill the algae, but the issue has gotten worse since the 2013 Big Thompson floods because of the nutrient influx and the mysterious introduction of a new species of algae that’s harder to kill.

That’s why even though the algae issue is nothing new, many residents noticed it for the first time late this summer…

The city’s been using powder-activated carbon to remove the taste-and-odor compound from the water and funneling more Big Thompson River water into its treatment plant, but each method has drawbacks.

Powder-activated carbon removes only 50 to 60 percent of the compound because it’s not great at trapping such tiny particles. Loveland’s treated water contains about 20 to 40 parts of the compound per trillion parts of water…

“It’s a very, very small amount, but most people are very, very sensitive to it,” Dickmeyer said. “It only takes about 5 parts per trillion for our customers to start noticing it.”

And within the last few weeks, algae started cropping up in the Big Thompson River, so diluting the taste with another water source wasn’t an option.

Loveland Water and Power is considering adding oxygen to the reservoir to discourage algae growth. The division is also considering more aggressive treatment options that won’t “cost a fortune,” Dickmeyer said.

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