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Almaden Lake Project

This 32-acre man-made body of water, once a privately owned gravel quarry, progressively formed as a result of the quarry operation in the late 1940s. Excavation for the quarry started at the center of Los Alamitos Creek and moved outward, transforming a meadow where dairy cows grazed into a lake.

Almaden Lake lies wholly within Almaden Lake Park and was opened for public use as a park in 1982. The lake offered a range of activities over the years, including fishing, swimming, pedal boating and athletic events. Its sand beach enhanced its popularity, but despite its beauty, the lake offers no value other than aesthetics. It is one of the most polluted in the state, according to a two-year screening survey on contaminants in fish from the state’s lakes and reservoirs.

Elementary mercury from the mines settled at the bottom of Almaden Lake and converted to methylmercury, resulting in its designation as an impaired water body. Almaden as having a 2.15 parts per million methylmercury result for largemouth bass, a reading that is the highest result among lakes with mercury above .044 parts per million.

CAlmaden Lakeleanup efforts
The water district has conducted numerous sediment removal and erosion repair projects along Alamitos Creek where it has title and easement and removed about 500 kilograms of mercury from the watershed, eliminating these sites as sources of mercury to the lake. However, upstream sources owned by private property owners and the county continue to discharge mercury to this lake.

Solar powered water-circulation machines known as solar bees (pictured at right) have helped prevent the harmful buildup of methylmercury in stagnant water at the bottom of the lake, but not to the extent needed to reduce mercury in fish. The geese and seagulls at the lake has exacerbated the problem of nutrients, which result in oxygen consumption and algae blooms. The mercury contamination - along with bacteria from the bird waste - has contributed to the lake's water quality problems. 

The latest:

District presents preferred alternatives to community at April 9 public meeting

The water district delved into the details of its two preferred alternatives for Almaden Lake during a public meeting this past spring at Castillero Middle School.

The new alternatives - Feasible Alternative 6 and Feasible Alternative 7 - maximize water features while addressing the fishery and environmental concerns. Both alternatives share the same traits except for one difference: One does not impact the existing levee at the boating knuckle location, while the other cuts into it slightly so as to allow a bit more water area for Almaden Lake.

A year-long collection of public input helped district staff develop two new options. To learn more about the new feasible alternatives, click this link to reach the project blog.  


Project Manager Rechelle Blank at 408-630-2615

Neighborhood liaison Tony Mercado at 408-630-2342

You can review the power point presentation from the district's Sept. 5 meeting by clicking the link below. At that meeting, the project team reviewed the hydraulic analysis for the restored creek connection and addressed the ongoing oxygenation pilot project at the Calero and Stevens Creek reservoirs that could determine new alternatives for addressing mercury methylation at the lake.

Project Fact Sheet [August 2013, PDF]

Review the previous feasible alternatives:

  1. Channel with East and West Lakes
  2. Channel with West Lake and Open Space
  3. Channel with East Lake and Wetland Planting Area - Eliminated due to mosquito nuisance concerns.
  4. Channel with East Lake and Open Space
  5. Channel with Open Space
  6. No Project

Also, review the chart that can be found by clicking here, a matrix of Feasible Alternatives that includes the cost for each alternative. These are the most up-to-date figures since the March 13 meeting when the alternatives were first presented.