The following is the position of the Santa Cruz Desal Alternatives group on potable use of recycled wastewater.
There are several serious drawbacks to Direct Potable Reuse (sending treated wastewater directly into the potable water distribution system) which should negate such an idea as a primary strategy:
1. Energy Use: The energy consumed by the treatment process is estimated to be approximately four times that of our current water supply. The treatment plant would run continuously—even when water in the river is plentiful.
2. Cost: The product water is the highest cost water (both capital costs and operating costs) short of desalination.
3. Health: There is credible evidence from independent scientists that trace amounts of endocrine disruptors and other contaminants of emerging concern present even in recycled water produced by state-of-the-art treatment plants may be harmful to public health.
Because of these drawbacks, Desal Alternatives recommends that Direct Potable Reuse be considered as a last-resort backup water supply strategy if and only if all of the following conditions were met: Continue reading
A five-member working group of the Water Supply Advisory Committee (WSAC) has reported to the WSAC its recommendations for augmenting the City’s Draft Conservation Plan. The Water Department will evaluate those recommendations and work with members of the working group to bring draft recommendations to the WSAC September meeting. The working group recommended that the goal of conservation be to reduce demand by 150 million gallons during the peak season (about 8%) by 2035. Download the report: Conservation Working Group Report.
Maximizing Rainwater Infiltration in Our Landscapes
Tuesday, May 26th, 7-8:30pm, Simpkins Swim Center, 979 17th Ave.
Low cost measures to maximize rainwater infiltration on individual properties can contribute to recharging our depleted groundwater aquifers. Find out how to be part of the solution to our water supply problems.
Speakers: Emily Corwin, Fall Creek Engineering; Mike Cloud, Geologist & Hydrologist; Sherry Bryan, Ecology Action
The Resource Conservation District conducts no-cost evaluations for property owners on storm water management. Continue reading
from Bruce Van Allen:
So now we get to the habitat benefits of recharging our aquifers.
A good example would be Bean Creek, which comes down from the Scotts Valley basin as a major tributary of the San Lorenzo River. Bean Creek has suffered greatly from groundwater depletion in the Santa Margarita. The creek’s “base flow” (roughly its average flow not counting storm-season peaks) barely supports life in the manner to which its riparian habitats were accustomed. This is mostly because as the Santa Margarita aquifer has been depleted, less water seeps from it into the creek. If the aquifer is re-filled, both the higher elevation of the groundwater and the underground water pressure within it will increase flows of some of the aquifer’s water to the creek through the ground. Continue reading
March 3rd, 7pm City Council Meeting on Water Rate Structure
A basic principle of conservation pricing is to charge for water based on how much water is used. The more you use, the more you pay. Although this seems like common sense, there are water utilities in California today that charge a fixed rate for each customer— no matter how much water the customer uses. Utilities sometimes value a predictable and dependable revenue stream over the need for conservation. Continue reading
Here’s what I’ve been hearing people say about the rain, “I wish we could store more of it”. That just about sums up Santa Cruz’s water problem. We get plenty of rain at times and can go for long periods without much rain. We need more storage to smooth out the dips.
In his proposal to use the old Cemex quarry on the North Coast for a reservoir, JoeBen Bevert points out that Santa Cruz has a low amount of storage in proportion to its annual water use compared to other urban water districts in this climate. The City’s storage in Loch Lomond Reservoir in relationship to its annual water use is approximately 1:1. San Francisco PUC has a 3:1 storage-to-use ratio. Continue reading
The City’s Water Supply Advisory Committee (WSAC) is trying to analyze strategies that would reduce the City’s water supply shortfall during drought years. The question is, just how big a shortfall are we facing during drought years? Climate changes could result in drought years that are worse than 1977, which is the current benchmark worst-case.
Whatever the WSAC settles on in terms of a future climate change scenario, the good news is that conservation measures are a powerful tool to reduce and even eliminate the shortfall in most drought years. I presented the following information to the WSAC that demonstrates that a small amount of reduction in our water demand has a multiplier effect on reducing our shortfall. That’s because every gallon of water we don’t consume in a normal year is saved in Loch Lomond Reservoir and available in future droughts.
Desal Alternatives has suggested for years that the City’s dramatic reduction in water demand—25% in the ten years ending in 2010—has improved our shortfall picture. But until now we never had access to the Confluence Model spreadsheet the City uses to calculate its shortfall. Access to the Confluence Model allows us to plug in the amount of actual current water demand, instead of using outdated demand estimates. The result is a very encouraging picture of our drought shortfall. Continue reading
The Santa Cruz City Council as well as the Board of the Soquel Creek Water District expressed their desire that the proposed desal plant be carbon neutral. There is a big difference between that desire and the feasibility of accomplishing it.
The obvious way to make a desal plant carbon neutral would be to power it with renewable energy. However, this option was dismissed by the 2005 EIR for the Integrated Water Plan. “… these sources are not feasible at this time for power requirements typical of large-scale industrial-type applications.” This statement is misleading. Continue reading
The one-hour video is now online of our forum on Conservation: Lessons Learned, with Conner Everts discussing Australia and Ron Duncan discussing the Soquel Creek Water District. Or watch the video on Community TV, Channel 27, Thursdays 8/14, 8/21, 8/28, and 9/4 at 9 PM.
Growth Increases Our Drought Risk
Santa Cruz needs water policies that will allow reasonable growth to continue without increasing demand for water.That way we can effectively manage our drought risk. A 2004 City Water Department report(1) put it this way:
“Continuing to provide water to new customers upon request, as is the current practice, may do harm to existing customers by making the potential water shortage situation worse than it would otherwise be.” Continue reading