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MMWD Blog: Think Blue Marin

Welcome to our blog! Written by staff at MMWD, “Think Blue Marin” explores all things water in south and central Marin—water supplies, conservation, new projects, watershed management, and more.

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Jul 11

MMWD Preparing for Electric Power Shutoffs

Posted on July 11, 2019 at 2:13 PM by Ann Vallee

Beginning with the 2019 wildfire season, PG&E will implement a new program called Public Safety Power Shutoff or PSPS. A PSPS event is when, due to extreme fire risk conditions such as a Red Flag Warning, PG&E may shutoff power for a period of up to five days.

To improve the District’s readiness to respond to a PSPS, this spring MMWD’s Board of Directors approved funding for portable generators that can be utilized at strategic sites to ensure we are able to deliver water to our customers. MMWD uses pump stations powered by electricity to fill our water storage tanks. Should a PSPS event occur, MMWD staff will move the portable generators throughout our service area to power our pump stations. While logistically challenging, the deployment of portable generators will allow for continued water service to District customers. 

MMWD portable generators
Portable generators ready for deployment 

Historically, PG&E power outages affecting the District have been short-term and occur during winter months when water demand is low, and generally impact a small number of pump stations. Unlike short-term winter power outages, electric power shutoffs during Red Flag conditions present a challenging scenario, as these conditions coincide with much higher water demand.  

In order to best manage this new scenario, when a PG&E PSPS event occurs anywhere in MMWD’s service area, we are asking that all customers turn off their irrigation system and restrict water use to indoors only for the duration of the PSPS. Reducing the demand on our system will serve two important purposes: It will ensure more water is available for firefighting if needed, and it will assist the District with our efforts to strategically deploy the portable generators. Your help is greatly appreciated! 

Beyond conserving water, preparing for a PG&E power shutoff event is similar to preparing for other disasters such as wildfire or an earthquake. One of the easiest yet most essential steps you can take to prepare is to set aside an emergency water supply. Keep at least a five-day supply of water for each person in your household. Plan for one gallon per person per day, for drinking and sanitation. Store extra water for pets and family members with special needs. Visit our emergency preparedness web page for additional tips. 

For more information about Public Safety Power Shutoffs, please contact PG&E or visit:

Public Safety Power Shutoff preparations
Jul 11

A Penny Per Gallon

Posted on July 11, 2019 at 11:44 AM by Ann Vallee

By Cassidy Lynn Bruner, Sir Francis Drake High School, MMWD 2019 Water Scholar

Grey clouds roll in from the North like a clump of dark molasses spreading miles above the ground. A rainstorm is coming. Falling, I descend from the sky and although my vision is blurry the beauty is clear. The massiveness of Mt Tamalpais' lusciously green being captures my attention first. It's beauty accented by rolling hills surrounding on all sides and the diversity of life that inhabits it.

Those 21,500 acres of protected watershed kept by rangers, volunteers, and other workers, hold a variety of life. Of the over 750 native plants known on Mt. Tam, 6 are found nowhere else in the world, and 49 are listed as threatened, endangered, or rare. The mountain is home to 350 native animal species, 46 of which are officially listed as threatened, endangered, sensitive, or rare. This land is not only preserving the existence of certain species and the important roles they hold, but the presence of the healthy and diverse ecosystems improve water quality.

As a raindrop, I continue on my journey to the ground, still reveling in the natural beauty of the open space of Mt. Tam. I plop into an abundance of other water droplets in Lake Lagunitas, one of the seven reservoirs on Mt. Tamalpais and in west Marin. From there I flow to one of the three drinking water treatment plants in the Marin Municipal Water District, where I am treated and tested for quality. After leaving the treatment plant and bidding adieu to the chemists who work there, I travel through 900 miles of pipeline around Marin. As I am pumped around this complex pipe system, I think of the engineers who planned and designed the arrangement and the service crews who keep everything maintained to top condition, maximizing function and freshness. Eventually, I arrive in someone's home or a business or some other structure within the Marin Municipal Water service area.

Every day, trillions of droplets like this one make the journey to locations all around Marin. While virtually all individuals use water on a daily basis, many fail to recognize the method of the system in which we obtain water, and the important work of the Marin Municipal Water District which facilitates it.

The indispensable value of the clean water Marin gets is measured from the hard work of the people in the background, the value of the land that is open for biological conservation among other uses, and the accessibility we each have to the water, for one gallon costs less than a penny.

Water plays so many different roles in our lives as humans, from a liquid to drink or clean, steam to provide energy, pools to swim, snow to ski, ice to relieve injuries or refrigerate nourishments, among numerous others including the fact that it makes up over 50% of the human body. In other living creatures as well, water provides some of these same services, and on the scale of the earth as a whole, water is an integral element.

Serving different mechanisms such as the water cycle purifying and allowing growth, to ice sheets reflecting the sun's light, and both saltwater and freshwater environments being a host to its own set of unique habitats, water has multiple uses that are fundamental components of the activity on earth. Being a key component of life as we know it, water is what differentiates the earth from all the other known planets in our solar system. As a prospective geological sciences major, water is one of the main systems I am expecting to study. Taking into account to the immense value it holds as a critical resource, I am eager to delve into the phenomenon of water as a powerful force seen through floods, storms, oceans, erosion, and more, as well as a crucial balancing force used to mitigate the effects of fires, dryness, infections and other dangers on a large-scale level.

The accessibility of clean water is imperative as it is truly what makes everything on earth possible. While people and children in numerous comers of the globe must walk miles to get only semi-clean drinking water, the work done by the Marin Municipal Water District shields us from this hardship in the best way possible.

There is so much that goes into providing the high-quality water the Marin Municipal Water District does. From engineers, to chemists, to biologists, to policy-makers, service crews, and volunteers, so many various skills are utilized to operate such an essential system for Marin County. Not only is this water system vital to delivering clean water to areas throughout Marin, but it plays additional and incredibly important roles in preserving the natural land. The service that the Marin Municipal Water District provides, for just less than a penny per gallon, is of utmost value to the residents of Marin County.


 "Health of Mt. Tam." Animals I ONE TAM,

 ''Where Your Water Comes From I Marin Municipal Water District - Official Website." MMWD 2,

About Cassidy
Cassidy Bruner recently graduated from Sir Francis Drake High School. She plans to study Physical Sciences at the University of Pennsylvania. When she’s not at Stapleton School of the Performing Arts practicing ballet or on the Drake field playing on the varsity soccer team, she enjoys baking, playing cards, and going on adventures around Marin.

May 13

Happy 100th Birthday, Alpine Dam!

Posted on May 13, 2019 at 9:06 AM by Ann Vallee

Alpine Dam under construction in 1918

 Alpine Lake Jan 2017
Nestled deep in MMWD’s beautiful Mt. Tamalpais Watershed, Alpine Dam continues to play an integral role in supplying clean, local water to our customers—a full century after its construction.

Even at 100 years old, Alpine is not the oldest dam in our system. Both Lagunitas (1872) and Phoenix (1905) were built before MMWD was established. After MMWD’s creation in 1912, one of the water district’s first actions was issuing a $3 million bond to build Alpine Dam to serve Marin’s growing population. Today, replacing the dam would cost an estimated $200-$300 million.

Work on Alpine began in the summer of 1917, but the outbreak of WWI caused difficulties for the contractor as labor and supplies became difficult to secure. MMWD took over construction in January 1918, completing work in January 1919. Alpine was dedicated in a dam-top ceremony on June 21, 1919.

Alpine is unique among MMWD’s seven dams as the only concrete one in our system (all the others are earthen). When it was built, the dam contained 27,719 cubic yards of concrete and held just over a billion gallons of water. The dam was raised in 1924 and again in 1941 to its current capacity of nearly 2.9 billion gallons—about 11% of our total water storage capacity.

Originally, water from Alpine traveled via gravity through Pine Mountain Tunnel and miles of concrete pipeline, then on to customers’ homes and businesses. Today, water from the lake is pumped up to Bon Tempe Reservoir for treatment at Bon Tempe Treatment Plant before supplying the southern part of our service area. When Alpine is full, water flows over its dramatic spillway and into Kent Lake. From there the water can travel on to San Geronimo Treatment Plant, or it can be released to support fish and other wildlife downstream in Lagunitas Creek. Alpine thus remains at the heart of our water supply system. Along with maintaining our pipes and storage tanks, taking care of Alpine and our other reservoirs is critical to ensuring a reliable water supply for the next 100 years and beyond.