Project Protects Marin County Creeks

Project Protects Marin County Creeks



Feb 2007 - A small 
grassroots community group in Marin County has completed a 
model stormwater capture project that protects Coho salmon 
streams, reduces bank erosion, saves water, and educates the 
local school children about how to protect the Earth. 
The project was completed by the Salmon Protection and 
Watershed Network, SPAWN, a community-based environmental 
nonprofit organization in San Geronimo Valley. 
The "creek friendly" project was unveiled in November at the 
Lagunitas School in Marin County. 
The rainwater harvesting system, captures rainfall from the 
roof of a playground lunch-shelter at the school during the 
stormy winter months and diverts it into a 30,000-gallon 
cistern that will serve to irrigate the School's Organic 
Garden Project during the dry summers. 
Left un-captured, the runoff would have drained into a 10-inch 
storm drain that empties out onto an already eroded bank on 
Larsen Creek, a salmon-bearing creek in the San Geronimo 
Valley, one of the major tributaries to Lagunitas Creek. 
Lagunitas Creek is listed as impaired for sediment, pathogens, 
and nitrates. 
"This project saves precious drinking water, saves the school 
money on their water bill, and reduces erosion," said Todd 
Steiner, SPAWN's director. 
Excess captured stormwater will be diverted into a vegetated 
swale where it will be allowed to percolate into the 
groundwater. 
"If this innovative and scaleable project was replicated 
throughout the watershed," said Steiner, "it could help to 
re-charge our underground aquifer, reducing the impacts of 
development that cause our creeks to go dry, stranding baby 
salmon, in the summertime." 
In 2003 SPAWN was awarded a $130,000 grant to do citizen water 
quality monitoring, nonpoint source pollution awareness 
outreach, and to implement an on-the-ground project to address 
nonpoint source pollution. One of the achievements funded by 
this grant is the rainwater catchment project. 
Between October and December 2006, San Geronimo Valley 
received half of last year’s rainfall, about 12 inches. This 
resulted in the capture of 11,922 gallons of stormwater runoff 
from the 1,600 square foot lunch-shelter roof. 
Roughly, for every one inch of rainfall, the cistern captures 
1,000 gallons of roof runoff. 
The project will be used over future years as part of science 
school curricula - calculating rainfall runoff from roofs and 
parking lots, and associated physical principles - and a 
watershed tour to demonstrate methods in creek care, 
sustainable water use and stormwater runoff mitigation.

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