Windsor Lake Closed Due to Algae, Festivities Shifted

Windsor Lake, photo courtesy of Town of Windsor

On Friday, July 23, the Town of Windsor closed access to the Windsor Lake beach and dog park until further notice. A precautionary water sample taken from the lake Monday, July 19 tested positive for cyanobacteria also known as blue-green algae.

The lake is closed, effective immediately, the swim beach is roped off, and access to the dog beach is locked. Swimming, bathing, and pets are not allowed on the lake until further notice.

Rentals and concessions will not be available during the closure. Annual permitted motorized and non-motorized boaters are allowed on the lake at this time to assist in agitating the water; however, water activities such as tubing and water skiing are not allowed. Non-motorized boaters can use their permits at their own risk. However, for health precautions and safety, staying out of the water is highly recommended.

“Last week, our team took precautions and issued an advisory to our community in addition to publishing messages across our communication platforms,” said Kendra Martin, Parks, Recreation & Culture operations and facilities manager. “With the results returning positive for blue-green algae, staff immediately closed access to the swim areas at the lake and are actively working to keep our community aware.”

Due to the closure, water activities for the Pack the Park and Lake, scheduled for Thursday, July 29, in celebration of Parks and Recreation Month, has shifted to Pack the Park, eliminating events at the lake and replacing it with a twilight swim at Chimney Park Pool, 421 Chimney Park Dr, Windsor, CO 80550, on Wednesday, July 28 from 6:30 p.m. – 8:30 p.m. Originally, the celebration intended to waive rental fees to the town’s aquatic rentals offered at Windsor Lake; instead, the admission fee to Chimney Park Pool will be waived, for one evening only, to accommodate the shift.

On Thursday, July 29, residents are encouraged to come out to Boardwalk Park from 5:30 p.m. to 8:30 p.m. to enjoy food trucks, view the competition between cornhole leagues, and watch a live concert beginning at 6:30 p.m. At 6 p.m., winners of the social media campaign #OurParksAndRecreationStory will be randomly selected and announced. As part of the celebration for Parks and Recreation Month, the Town of Windsor highlighted its staff and encouraged its social media audience to share their story on their social media.

“We will slightly shift festivities by eliminating all water activities on the lake and host a free twilight swim at Chimney Park Pool the night before and continue with plans to celebrate Parks and Recreation Month at Boardwalk Park Thursday, July 29 from 5:30 pm – 8:30 p.m.,” said Martin. “We are in a situation where weather plays a partial role in how quickly algae clears from our lake; until then, we will provide our residents alternative safe recreational opportunities for all ages and abilities to continue enjoying what we offer here in Windsor.”

What is Harmful Algae? 

Blue-Green Algae, which are not really algae, are a type of bacteria, are common in lakes throughout Colorado. The algae multiply rapidly—and are impacted by a combination of unusually sustained hot weather, stagnant water, and stormwater runoff that includes nutrient pollution from fertilizers—to form blooms and scums.

What Contributes to Blue-Green Algae Growth? 

Polluted stormwater runoff can have adverse effects on plants, fish, animals, and people. Too much nitrogen, potassium, and phosphorus in the water is known as nutrient pollution and can cause algae to grow faster than ecosystems can handle. Significant increases in algae harm water quality, food resources, and decrease the oxygen aquatic life. Add sustained hot temperatures and conditions exist for this type of algae to thrive.

While visitors are advised to use the water at their own risk, they can still enjoy the Dr. Tom Jones Trail, a 2.5-mile trail around Windsor Lake, the volleyball court, catch and release fishing, the playground, Boardwalk Park Museum, and the park in general. Additional swim options include the Community Recreation Center (CRC), Chimney Park Pool, and Eastman Park River Experience. The CRC’s swim options include a pool with three lap lanes, a hot tub, a lazy river, and a water slide. For hours of operation, admission to the pools, and information about events happening in Windsor, visit

The Town of Windsor will continue working with the Colorado Department of Public Health & Environment and closely monitor the bacteria levels.

Stay up-to-date with the latest information by visiting, following us on social media (@windsorprc), or subscribing to our newsletter.

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