(Note: The decision on Syar’s permit extension before the Sonoma County Board of Supervisors on June 10 was postponed until Tuesday, June 8, at 2:10 pm.)
It will be very interesting to see today how the Board of Supervisors addresses the issues around the requested Syar gravel mining extension as it relates to water supply and filtration.
In conversation yesterday evening with Pam Jeane (SCWA Asst. Managing Engineer) and their fisheries biologist (David Manning) in their Guerneville SCWA public meeting on water shortages, the question came up of whether SCWA would be providing comments to the Supervisors on the impacts of gravel mining on water supply. They stated explicitly that they have not been asked to do so by their boss(es), and so would not be providing any comments.
This is very odd and unfortunate, since it is a hydrological and geological reality that the gravels and sands of a river aquifer are porous. In the Russian River, these 25-40% voids within the gravel bed are filled with water, naturally and for free, every winter. This is a huge reservoir within the gravel bed aquifer of the Russian River.
So, removal of a cubic yard of gravel to aggregate mining removes approximately ~1/3 cu. yd. (about 9 cu. ft, or 68 gallons) of water stored within that gravel and sand. Gravel mining leads directly to lessened water stored within the aquifer, and directly results in lower flows within the river, as those stored waters are slowly released during the dry months as the “base flow” of the river. This is a very significant part of our water supply (and critical fish habitat) during the dry months, as well as for all the other users who are drafting water from the river for agriculture and municipal uses and for swimming and boating. This base flow is supplemented by the releases from Lake Sonoma and Lake Mendocino to meet the state mandated minimum flows for fish and recreation. So, the less water stored within the aquifer, the more water has to be released from the reservoirs to maintain the flows. This is all compounded by the overdrafting of the river (“over-allocation”) during the summer, with more water taken out of the river than naturally is flowing in it.
(For literally a ‘text book’ examples, discussing the Russian River and other western rivers, see:
Jeffrey Mount [Chair, Geology Dept, UCD], California Rivers and Streams, the conflict between fluvial process and land use, UC Press, 1995, Chapter 11, Mining and the Rivers of California; also,
Thomas Dunne and Luna Leopold, Water in Environmental Planning, W.H.Freeman and Co, 1978, Groundwater storage, p.198+ )
As you well know, in addition, the state Dept. of Health 1949 permit for SCWA’s pumping of water from the river without any filtration (and no treatment required except chlorination for possible in-pipe contamination) is premised on the spectacular abilities of our aquifer to filter our water for cleanliness.
It is very unfortunate that the institutional conflicts between governance roles of the Sonoma Co. Board of Supervisors and the Board of Directors SCWA leaves this critical information off the table for their informed consideration of river gravel mining. What we need is for the Board of Directors to instruct their senior staff to provide this kind of data to the Board of Supervisors.
Any help you can provide to get this done would be most welcome.
Thanks for your ear on this. If you’d like to discuss these issues further, please let me know – I’d be happy to sit down with you.