Lake Health and Water Quality
Some of the most celebrated attractions in the Park District are its six beautiful open-water lakes. The natural and constructed lakes are foundational features and an essential part of the East Bay’s landscape, providing vital aquatic habitat, recreational opportunities such as swimming, boating, and fishing, and a peaceful connection to nature for visitors who gaze upon the waters.
A critical part of the District’s management of these lakes is the ever-present need to maintain their infrastructure and to monitor water quality. Lake infrastructure can change over time, and water quality can fluctuate, especially in recent years with the challenges of climate change.
There are several ongoing projects to maintain and improve Park District lakes, and new technologies have been deployed to find innovative solutions to ongoing problems.
Two of the District’s oldest and most popular swimming lakes, Lake Anza in Tilden Regional Park and Lake Temescal, have both been closed to swimmers for the past couple of seasons due to water quality issues. However, innovative efforts to improve water quality have resulted in both lakes reopening for the 2023 swimming season.
At Lake Anza, an underwater oxygenation system was installed in early 2020 to prevent growth of blue-green algae, which can be harmful to humans, dogs, and aquatic wildlife. The pump system emits bubbles of oxygen deep within the lake that helps to limit the growth of blue-green algae.
In the fall of 2020, nanobubble technology was introduced to Lake Temescal to help reduce harmful algal blooms. Nanobubbles, 2,500 times smaller than a grain of salt, add oxygen to the lake to reduce excess nutrients, making it harder for blue-green algae to thrive and improving water quality and aquatic health.
Water quality is routinely monitored in all the District’s lakes and regularly published on the website. When planning to visit a lake for recreational use, be sure to check our website for water quality status, follow safety guidelines, and stay out of water (pets, too!) when warning signage is posted.
For current water quality conditions, visit www.ebparks.org/natural-resources/water-quality.
