Milavec Reservoir Water Quality

Milavec Reservoir is a beloved community resource in Frederick, with opportunities for fishing, non-motorized boating, and walking trails. But like many bodies of water across Colorado, Milavec is at risk for Harmful Algal Blooms (HABs), particularly during warmer months.

What Are Harmful Algal Blooms?

HABs are excessive growths of cyanobacteria (commonly called blue-green algae). These blooms can produce cyanotoxins that are dangerous to people, pets, and aquatic life. Blooms often occur in stagnant, nutrient-rich waters, especially during warm weather.

Exposure Risks Include:

  • Skin rashes and irritation
  • Nausea, vomiting, and diarrhea
  • Liver and neurological damage (in severe cases)
  • Illness or death in pets who swim in or drink contaminated water

Milavec Reservoir is actively monitored, and advisory signs are posted when blooms are detected.

What the Town is Doing to Prevent HABs

The Town of Frederick is taking a multi-pronged, sustainable approach to reduce and prevent Harmful Algal Blooms.

Solar-Powered Mixers (Installed 2020)

Three solar-powered mixers circulate surface water, mimicking wind to prevent water stagnation. This lateral movement helps reduce the conditions that lead to bloom formation.

Learn More About Mixers and Circulators at the Lake.

Ultrasonic Pulsar Units (Installed 2024–2025)

The Town has installed pulsar units and advanced ultrasonic systems that emit precise sound frequencies to disrupt algal cell structures. This causes algae to sink and die without releasing toxins.

  • Targets most cyanobacteria and green algae
  • Operates 24/7 with remote cloud monitoring
  • Safe for fish and beneficial bacteria

Explore WaterIQ Technology

Subsurface Aeration System (Installed 2020 & 2024)

Fourteen aeration units, called “bubblers,” are arranged in a grid throughout Milavec. These circulate water vertically to:

  • Improve oxygen levels throughout the water column
  • Support healthy aquatic ecosystems
  • Reduce conditions that promote algal blooms

The system was fully upgraded in 2024 for optimal efficiency.

View Robust-Aire Diffused Aeration System

Nutrient Binding Treatment (Coming Soon)

A chemical treatment is being developed to bind excess phosphorus and nitrogen in the water. These nutrients fuel algae growth, and the Town can further reduce bloom severity by locking them up. This treatment is not a pesticide and will be selected with environmental safety in mind.

How You Can Help

Community participation is essential in preventing HABs:

  • Use fertilizer sparingly and keep it away from storm drains
  • Pick up pet waste to prevent nutrient runoff
  • Report suspicious algae to the Town

Keep pets and children away from discolored, scummy, or foul-smelling water.

If you or your pet are exposed, contact Poison Control at 1-800-222-1222.

Stay Informed

We post updates throughout the summer on social media and the Town website. Look for HAB advisories, safety tips, and progress on our water quality initiatives.

Visit the CDPHE HAB Page for more information on Harmful Algal Bacteria.

For questions, contact the Frederick Parks & Open Space Department at 720-382-5805.