If, when skimming through your mail, you regularly throw out the letters that seem impertinent to you, you may have already thrown out a very pertinent pamphlet that may have innocuously been disguised as spam. The city of Davis recently distributed its Water Quality report for the year of 2011 — statistics abound.
Upon unraveling the neatly-folded pamphlet, a wealth of information is catalogued before your eyes. On one side, a thorough background on the report gives the reader some exposition before they dive into the Excel spreadsheet of water statistics on the flip side.
The report was prepared in accordance with the U.S. Environmental Protection Agency and the California Department of Public Health regulations that require water providers to report annual water quality information to their customers.
It outlines all of the components found in our water, where said water comes from, how the water compares to state and federal standards and other related information.
Davis’s water is pumped from 20 municipal wells which draw water from aquifers deep below the surface level. The newest addition to these wells is located on 3608 Chiles Road and taps into water at depths ranging from 735 feet to 1560 feet below the surface.
The pamphlet goes on to mention that, “The water is filtered naturally by sands and clays as it passes through geologic formations.”
In addition to the natural filtering, each well has an assigned chlorine tank designated with the duty of injecting a 12.5 percent solution of sodium hypochlorite into the well site.
Turning it over, one is confronted with a detailed chart delineating the amount of a certain substance found in our water, showing whether it meets or exceeds Maximum Contaminant Levels (MCLs), or Public Health Goal (PHG) standards. Most constituents of our water managed to stay below the Public Health Goal Level — which is the level of a contaminant in drinking water below which there is not an expected or known detriment to health from consuming it.
“The City of Davis met all of state-required mandates,” said Marie Graham, the city’s utility program coordinator. “Public Health Goal is set with no risk involved in terms of health. It’s not uncommon. If MCLs were exceeded, we would have to take action. We’re very pleased we met all the standards.”
Nevertheless, levels of arsenic, gross alpha, radium-228, and uranium were all at levels that exceeded the PHG level. The potential source for all of these is listed as erosion from natural deposits.
Jason Clegg, a senior civil engineering major, sheds a little light on the matter of the contaminants. Clegg is currently enrolled in an Ecology 155 Water Resources course.
“Oftentimes placing pipes into aquifers to pump water for use is a risky venture. Aquifers are surrounded by a relatively impermeable layer of clay. This clay resists seepage and basically acts like a giant storage tank underground,” Clegg said. “As pipes are pierced through the clay layer, contaminants can leak into the aquifer, decreasing the quality of the water. Proper engineering needs to be done to make sure that there are no dangerous contaminants that can seep into the aquifer when placing piping into the aquifer.”
Other constituents mentioned prominently in the report were nitrate, boron and radon. Three of the wells in Davis have boron concentration levels that exceed the notification level of 1,000 parts per billion.
In a statement issued to The Davis Enterprise last year, Bob Clarke, the interim director of Davis Public Works, noted that the constituents found in the water were “well below limits that would be considered harmful under state and federal standards.”
Further information can be found by contacting the Davis Public Works Department at 757-5686 and asking to speak to Marie Graham, Rick Thompson or Diana Jensen. Past water quality reports can be found at cityofdavis.org/pw/water/WaterQuality.cfm.
ANGELA SWARTZ contributed to this article.
ANDREW POH can be reached city@theaggie.org.
