After 143 years, Oakland’s Lake Merritt Reunites with the Bay

Map of Historic Lake Merritt
The lagoon now known as Lake Merritt, as seen in 1800. Image courtesy of the Oakland Museum of CA.

A gem at the heart of Oakland, Lake Merritt has been many things – the nation’s first wildlife refuge, beloved waterway, sewage-filled cesspool, and even the rumored home to a lake monster. There’s one thing that Lake Merritt has never been, however – and that’s a lake.

What we now call Lake Merritt has for most of the past ten thousand years been a tidal lagoon where the waters of several East Bay creeks met the brackish tides of the Bay. Ringed with mudflats and tidal marsh, this lagoon was home to an abundance of native wildlife, including hundreds of species of birds.

This changed dramatically in1869 as Oakland Mayor Samuel Merritt dammed the channel connecting the lagoon to the Bay. Later becoming the 12th Street Bridge, the lagoon’s water was forced through narrow culverts on its way in and out of the Bay, significantly reducing circulation and largely disconnecting the waterway from the rest of our great estuary.

Over the next century, the lake was inundated by raw sewage and considerable amounts of pollutants. 62 storm drains were routed straight into the lake, bringing with them car oil and other toxins from the city’s streets. To this day, the majority of these storm drains remain unfiltered. All of this has resulted in poor water quality, low oxygen levels, algae blooms, and numerous massive fish kills. The Environmental Protection Agency declared the lake an “impaired water body” in 1999.

Residents’ Effort Leads to Historic Project to Improve the Lake

Spurred by a development proposal near the Lake’s 12th Street shoreline, a group of residents got together to chart out a different future for the Lake. Named the Coalition of Advocates for Lake Merritt, the group drew up a proposal to reduce the bridge from twelve lanes to six, increase the width of the channel, and increase public access and wildlife habitat.

Oakland elected officials supported the plan and with the overwhelming approval of a bond measure (Measure DD) in 2002, the plan was put into action. Since that time, the City of Oakland has rebuilt the 12th Street Bridge and is actively removing tide-blocking culverts and widening the channel that connects the lake to the Bay. Several acres of newly restored wetlands are being created along with a 4-acre park and numerous walking paths.

Once the project is completed, estimated by the City to be late this year, the amount of water currently going in and out of the lake with the tides will be doubled, significantly improving water quality and circulation. The new wetlands will filter toxins out of the water, provide habitat for young fish and birds, and offer a pleasant experience for the thousands of walkers, joggers and bikers that enjoy the lake every day.

While there is still considerable work left to be done to restore the health of Lake Merritt, this project can bring a renewed sense of hope and determination that this is just the beginning of an ecological transformation in the blue heart of the city.

For more information on the history and the transformation of Lake Merritt, read KQED Quest’s story, “Polishing Oakland’s Crown Jewel: Lake Merritt Reborn” and “Undoing the 1950s – The Death and Revival of Lake Merritt” by the Alameda Magazine. You can follow the daily progress in photos by visiting Erik Neiman’s 12th Street Project blog. Gene Anderson’s Our Oakland blog also shares with us some fascinating old pictures of the lake. 

UPDATE – February 2013:

The 12th Street Bridge (really, more of a dam), which had blocked regular Bay tides from Lake Merritt for over 140 years has now been completely removed! The City of Oakland held an event to celebrate – read more about the celebration our Save The Bay blog here. The new bridge will allow for a 100-foot wide free flowing tidal channel underneath, doubling the amount of water flowing between the Lake and the Bay. A new tidal marsh area has been carved out to improve wildlife habitat and work to build new tails and landscaping is currently underway. This bridge replacement was the biggest piece of the project. Next the City of Oakland will be working to remove/alter other impediments (such as the 10th Street Bridge) which have been preventing boats for over a century from being able to go between Lake Merritt and the rest of the Bay. Check the City’s website, or back on this blog for future updates. Additional information about the City’s work to stop pollution and restore habitat can be found on their Creeks, Watershed & Stormwater website.

UPDATE – June 2013:

What’s next for improvements to Lake Merritt? City staff are currently designing human-made floating wetlands, to be installed near the shoreline to help filter out toxins of the water and provide habitat for wildlife. Learn more about what they’re looking at with our latest blog post, “Floating Wetlands, Coming to a Bay Near You?

7 thoughts on “After 143 years, Oakland’s Lake Merritt Reunites with the Bay

  1. Excellent article; but note that whenever there is a 50% chance of rain in the forecast, county tidal gates on the channel will be closed, cutting off all tidal circulation during the incoming tide at a time when polluted runoff is entering the Lake. This is when the lake is often stratified and oxygen levels at the bottom dip to 0-2 ppm.

    We still have a lot of work to do with the county to minimize gate closure except when absolutely necessary to prevent flooding. In addition, more storm drain filters, trash collection nets at Glen Echo creek and less littering will be needed before the Lake begins to reach its potential. It would also be nice to install the proposed aeration system to prevent bottom fauna from dying when the flood control gates block incoming tides, stratification occurs and oxygen levels drop. Note that the Lake is also impaired (on 303D list) due to low oxygen.

    But, we are on the right path. The 12th Street project, when coupled with the removal of bottlenecks at 10th and 7th Street by 2015, will improve tidal circulation most of the time. Thanks for helping Lake Merritt.

  2. I’ve noticed the water level has gone down significantly is this a direct result of the channel opening? If so, was it anticipated?

  3. Hi Rachel,

    Good question! I passed it on to Rebecca Tuden, a Watershed Specialist with the City of Oakland to help us understand what might be going on. Here is her response:

    “The Lake’s tidal prism is much greater now with the wider channel. As a result we are seeing more extremes in the high and low tide. In fact, we anticipate the formation of some mudflats around the Lake as a result.”

    In other words, now that the channel connecting the Lake and the Bay has been widened, Lake Merritt is impacted much more by the Bay tides than it used to be. This means higher water levels at high-tide and lower water levels at low-tide. Much more like the Lake used to be before it was disconnected from the Bay.

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