Article

A Water Quality Snapshot

by Brendan Bane

Aug. 22, 2013—Nitrate levels in the waters of Santa Cruz County have decreased since last year, according to the Coastal Watershed Council’s 2013 Snapshot Day report, with the number of test sites not meeting state water quality standards having fallen from 16 percent last year to 7 percent this year. The word on other pollutants is mixed: The percentage of test sites exceeding the standard for E. coli concentration stayed the same at 29 percent, but more sites exceeded the standard for orthophosphate and total coliform concentration than last year.

“The big, general, difficult question to answer,” explained CWC Executive Director Greg Pepping, anticipating the question, “is how is our water doing? The answer is always a mixed bag. In some cases we have pretty pristine water. In some places, it’s pretty dirty.”

Another figure emerging from the report: more than 30 extra volunteers joined the Snapshot Day effort this year.

The annual report is compiled from data collected during the annual water-monitoring event hosted each May by the CWC, which relies on an unconventional method to acquire its data—sending forth citizen scientists to collect samples.

When Snapshot Day calls, people of the county don rain boots, equip themselves with scientific instruments and venture toward waterways to perform tests. This year they monitored 70 testing sites across 40 coastline miles from Waddell Creek to the Pajaro River.

The Offenders
Nitrates and orthophosphates aren’t always dangerous. You can find those chemicals in plants and dirt, but they’re also in fertilizers and detergents. When enough of them accumulate in water (to about 30ppm), fish begin to show signs of poisoning. High concentrations can create aquatic dead zones, where marine life is absent, and algal blooms may spring up. Because of their potentially toxic qualities, both nutrients are benchmark molecules for water assessment.

Coliform bacteria thrive almost everywhere. E. coli (one kind of coliform bacteria) thrives mostly in human and animal waste. While they are not necessarily harmful, those organisms can signal the presence of dangerous pathogens that are harder to detect.

The Results
Only 7 percent of sites exceeded the allowable standard for nitrate levels, and just two sites came close to 30ppm. Two beach sites near the Pajaro Dunes (an area that also measured high last year) came close to the toxic level. CWC program coordinator Debie Chirco-Macdonald speculates the area’s agriculture may be the cause. “All the Watsonville sloughs flow through the Pajaro Valley,” said Chirco-Macdonald. “They run through urbanized areas and croplands, and some of the contributors are animal waste, detergents and fertilizers.”

The orthophosphate standard was exceeded at 20 percent of sites. Struve Slough (also in Watsonville) came in with the highest count, measuring over five times that standard.

The Bacteria
Chirco-Macdonald said she is optimistic about the E. coli results. “When I look at E. coli, which is a great indicator of water quality, I see that much of our watersheds are in pretty good shape.” The majority of sites, at 71 percent, were below the standard. Three sites did reach levels of concern. Noble Gulch, which drains to Soquel Creek, Pilkington Creek by the Santa Cruz Museum of Natural History, and a small creek near Davenport, were the worst offenders. All three also scored poorly last year, with Pilkington showing a dramatic rise in E. coli count. The majority (80 percent) of sites assessed were below the total coliform standard.

What Does It Mean?
Because Snapshot Day takes place over the course of a single day, it represents only a pixel in a much larger picture of water quality. But the information is still valuable, and Snapshot Day isn’t the only event of its kind. CWC executive director Pepping shared his aspiration for cooperation among other water monitoring events. “We hope to share data with the city and county,” he said. “We have a part of the story, and they have a part of the story—we want to fuse those together to achieve a bigger picture.”

When asked about the best way to clean up our water, Pepping explained that the pollution stems not from one large source but from many small contributors, and that the best fix may be efforts like Snapshot Day, where people are engaged on an individual basis.

“The problem is what we call nonpoint source pollution, meaning that bit by bit we’re making our rivers dirtier,” he said. “But the beauty of it is that bit by bit we can make a difference.”

Click here for the 2013 Snapshot Day report.

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