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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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Jan 18

Lagunitas Creek Spawner Update: A Glass-Half-Full/Glass-Half-Empty Situation

Posted on January 18, 2017 at 8:38 AM by Ann Vallee

by Eric Ettlinger, Aquatic Ecologist

The current state of affairs in Lagunitas Creek can be described as a glass-half-full/glass-half-empty situation. Or more accurately, a reservoir-full, streambed-empty situation. By the end of December the coho salmon run was on track to be larger than the parent generation of three years ago and continue the generational improvements we’ve seen for each of the last five years. But then came the unrelenting storms of the last two weeks. On the positive side those storms filled MMWD’s reservoirs and produced the high flows that can create and improve salmon habitats in Lagunitas Creek. On the negative side those flows destroyed many coho redds, washed away some of our salmon habitat structures, and severely hampered our survey work. We’ve heard rumors of fresh coho out there (and steelhead should be starting to spawn too), but we haven’t been able to see them ourselves.

stream gauge
The stream gauge in Samuel P. Taylor State Park at 2,500 cubic feet per second

The most recent storm raised Lagunitas Creek flows to 4,300 cubic feet per second, which was the third-highest flow in 35 years. In the coming months we’ll see if this flood had significant impacts on incubating salmon eggs and/or last year’s fry. Previous major floods in 1998 and 2006 resulted in very poor egg survival, and we expect to see relatively few fry again this summer. One-year-old juvenile coho have survived recent large floods successfully, likely by seeking out slow water areas on floodplains. Ironically, it may be moderate storm events that are most deadly, because flows stay confined in the stream channel and slow water habitats may be hard to find. This summer we’ll be enhancing a number of areas on Lagunitas Creek to provide exactly those kinds of slow water habitats. On an optimistic note, the floods this season have risen and receded rapidly, hopefully subjecting coho fry to fast, confined flows only briefly. In late March we’ll start counting the surviving smolts as they migrate to the ocean and, one way or the other, that data will contribute to our understanding of how salmon survive floods and what we can do to help.

Jan 13

In the News

Posted on January 13, 2017 at 2:58 PM by Ann Vallee

by Charlene Burgi

Misty
 Misty checks out a nature-made rain garden
Lately not a day goes by without weather warnings notifying me of blasting blizzard conditions, flash flood warnings, ice on the roads and recommendations to stay indoors. The warnings, however, are not exclusive to us here in Lassen County. While watching the Bay Area news this week, I saw highway and road closures throughout Marin, evacuation and flooding in San Anselmo, and Corte Madera Creek rising to flood stage. I even saw videos of people surfing and boogie-boarding down rain-swollen Mill Creek.

These news warnings are a reminder that we need to be extremely careful when landscaping to keep our homes safe. Standing water or flooding can be an indicator of drainage design flaws. Sometimes these flaws do not reveal themselves until we experience what is known as the 100-year-storm scenario. A mild or modest rainfall may have no ill-effects on our property, but then an unusually big storm exposes the problem. An example of this occurs when water can no longer percolate down into the soil before running off. If the runoff exceeds the drain capacity on the property, or if the grading was crowned or sloped toward the house, excess water can end up under the house—or in the house if the home is on a slab. A good drainage design calculates for the worst historical rain conditions to draw water away from the house.

There are steps we can take to correct design flaws and help stormwater "slow down, spread out and soak in." If you live on a hillside, you can create multiple bioswales, such as bark-filled troughs, along the width of the hillside. Stormwater collects and slowly percolates into in each swale before continuing to the one below, thus eliminating the rush of unrestrained water flowing off the hillside. 

dry creek bed
Functional dry creekbed
Trenches designed as functional dry creekbeds can divert water away from the house and into a rain garden—a simple, shallow, pond-like area where the water can safely collect. Landscape your rain garden with plants able to withstand a lot of water in winter and minimal irrigation in the summer. Many iris, Monarda, asters and even the monarch-butterfly-attracting Asclepias are great for sunny rain gardens. Or choose ferns, blue-eyed grasses and Mimulus for shade. For more plant ideas, visit: raingardenalliance.org.

If you live in a flood zone, be prepared to evacuate if instructed to do so. In addition, plan ahead by stocking cupboards with extra food and water in case you are told to "shelter in place," lose power or are unable to get to a store. Keep extra warm clothing and shoes in your autos and do not attempt to drive through flood waters.

Be safe and have a great weekend.
Jan 06

MMWD Watershed & Road Closures

Posted on January 6, 2017 at 4:21 PM by Ann Vallee

Be advised, the Marin Municipal Water District’s (MMWD) Mt. Tamalpais Watershed will be closed to the public due to the increased risk of mudslides, falling trees, rock slides and failed stream crossings starting Sunday, January 8, 2017. Multiple roads and gates will be closed in and around watershed in alliance with the Marin County Fire Department and Public Works Department. 

MMWD plans on closing vehicle access to the watershed by closing key access points listed below:

Gate to Phoenix Lake Park (Also known as Natalie Coffin Greene Park) (link to map)
Gate to Sky Oaks Watershed Headquarters (Bon Tempe, Lake Lagunitas) (link to map)
Gate at W. Ridgecrest Blvd. at Fairfax-Bolinas Rd. (link to map)

The Marin Public Works Department will close Bolinas-Fairfax Road beginning Saturday, January 7, at 4 p.m. at the Meadow Club gate (link to map) and at the Highway 1 gate (link to map).

MMWD’s watershed, roads and gates will reopen to the public after the storm passes and we have a chance to cleanup as necessary.

For the latest information on MMWD’s watershed closure, call 415-945-1195 (recorded message). For the latest weather information, visit the National Weather Service’s website. For countywide closure updates, call the Marin County Fire Department at 415-499-7191 (recorded message).