Opinion: Water from Devil’s Slide for MWSD: What are the facts?


By on Fri, June 27, 2008

Paul Perkovic is Board President of the Montara Water and Sanitary District (MWSD), however this article reflects his individual views and does not indicate a position of the District.

There has been discussion in the community about whether MWSD should use water from the Devil’s Slide project. This article summarizes what is being said, what is known, and what can be concluded. It is not intended to advocate for any particular solution, just to present facts and background information.


  • Far less Devil’s Slide Tunnel water is available than claimed
  • Its reliability is not yet proven
  • Construction costs could be $175,000 per acre-foot or more for pipelines and treatment
  • Proven alternatives can be built at approximately $10,000 per acre-foot
  • Recycling water may provide new water, cost savings and environmental benefits for Montara / Moss Beach citizens
  • MWSD’s new Alta Vista Well may solve much of the existing water supply deficit

What is being claimed

Jim Larimer, an elected Director of the Coastside County Water District (CCWD), writes on TalkAbout, "Ask MWSD why they did not attempt to get the 1,000 gallons per minute of water that is coming out the Tunnel Project?" in one of his postings.

Charlie Gardner, an elected Member of the Governing Board of Cabrillo Unified School District, echoed that same question here on Coastsider, asking: "The tunnel project my company is currently constructing has enough water coming out of the mountain to relieve the moratorium. What has MWSD done to make that available?"

What are some of the facts?

Charlie Gardner provided prompt, informative answers to the questions I posed. It is remarkable what can happen when we work together towards solutions, rather than attacking each other. Jim Larimer, on the other hand, continues to defend his recklessly irresponsible claim of 1,000 gallons per minute, and refuses to answer any questions about his own district.

Charlie Gardner is a civil engineering construction Project Manager with Kiewit Pacific Company, which is building the tunnel, so he may have access to relatively reliable information.

Mr. Gardner reports that the "current yield of dewatering from the tunnel is in the range of 25-50 gallons per minute." That is a far cry from the 1000 gallons per minute being tossed around on TalkAbout as "truth" by Jim Larimer.

A yield of 25 to 50 gallons per minute (gpm) is equivalent to about 40 to 80 acre-feet of water, a common measure in the water utility industry.

Construction cost estimates

Mr. Gardner suggested very rough cost estimates of $1 million for a treatment plant to bring this water up to public drinking water standards, $3 million for a pipeline, and $3 million for other costs. This gives a total estimate of $7 million, or a capital cost of $87,500 to $175,000 per acre-foot, if we accept Mr. Gardner’s estimates as realistic.

I sincerely thank Mr. Gardner for his answers and spirit of cooperation. It confirms that the MWSD Board already has better options in hand, namely, desalination, which has a capital cost of approximately $10,000 per acre-foot, or water reclamation and recycling, which is currently being pursued as a regional solution to water needs by Sewer Authority Mid-Coastside.

These are all future projects that would be paid for entirely by new development, not existing customers, after MWSD has brought the antiquated Citizens Utilities system up to contemporary water system design standards as promised in the Measure V campaign in 2001. The community committed, by an 80.66% vote, to the direction undertaken by the MWSD Board.

Better, cheaper water sources available to MWSD

Desalination is reliable, drought-proof, and has a predictable and dependable yield. A desalination plant can be built in modules, as capacity is needed. Desalination is generally viewed as a high-cost water source with potential environmental problems. However, as illustrated by a quick "back of the envelope" type sanity check calculation, it is far less costly than potential water, of unknown reliability and quality, from the Devil’s Slide Tunnel.

Recycling is another future water supply option. Like desalination, it is reliable and drought-proof. Major obstacles to use of recycled water include cost of treatment to meet needs of the floriculture industry and public perception of "toilet to tap" in some communities (locally, for example, Redwood City).

MWSD also has the new Alta Vista Well as an additional water source. Reliable yield and permitting issues are still being worked out with the Coastal Commission.

For those who base their decisions on facts, I hope this will put the issue of water from the Devil’s Slide Tunnel as a solution to MWSD’s water shortage problems to rest. It is not an economically viable solution.

Click below for more…

What about an intertie to NCCWD?

Mr. Gardner also brings up his view that interconnection to the North Coast County Water District (NCCWD) system would be beneficial. The community can evaluate the cost estimates for construction of a pipeline against the perceived benefits, and decide whether that is an improvement that the Montara / Moss Beach community wants to pay for.

NCCWD gets 100% of its water from the San Francisco Public Utility Commission facilities, already pre-treated using a different (and incompatible) disinfection process than either MWSD or CCWD. Therefore, capital costs of conversion of existing clorination systems to cloramine treatment would add to the cost. Additionally, such an interconnect and conversion to cloramine would preclude an intertie to CCWD.

MWSD already has identified in its 2004 Water System Master Plan that an eventual intertie to the CCWD system would be desirable. That document has been approved by the Board. Therefore, the claim that MWSD has no plan for an intertie to CCWD is also a falsehood, no matter how many times it is repeated.

Celebrate the Community’s Achievements on August 24

Your local Montara Water and Sanitary District Board of Directors has moved aggressively to resolve the long-standing problems with the water system operated by Citizens Utilities. We are just coming up to our Fifth Anniversary for the water system as a public service, and the Fiftieth Anniversary of the District.

Community members who want to know more are encouraged to attend our Fiftieth Anniversary Celebration at the Point Montara Lighthouse, Sunday, August 24, 2008, from 1 p.m. to 4 p.m. More information will soon arrive with your water bill.