River snapshot

Volunteers take on the task of ‘photographing’ the Truckee River and Lake Tahoe for science

Mark Walker tests the depth and speed of Dry Creek.

Mark Walker tests the depth and speed of Dry Creek.

Photo By Gabriel Doss

On a bright Saturday morning, Mark Walker, an assistant professor at the University of Nevada, Reno, and a graduate student, Jody Benesch, stood alongside Dry Creek where it runs behind the almost-completed Mervyn’s off South Virginia Street near Home Depot. They were testing the water depth and speed of the creek.

The collected information could be used to compare with other data to get a sense of the health of part of the watershed at a particular time. “If we combine the measurements with the flow passing by … we can get an estimate of what’s passing through,” Walker explained.

Although Walker and Benesch were testing just water depth and speed, many other groups were performing more involved observations elsewhere along the river. They were just two of many volunteers from around the Truckee Meadows and Tahoe who gathered May 4 in an effort to test the water quality of the Lake Tahoe and Truckee River watersheds.

“Other groups are taking pictures, assessing the habitat, documenting litter, erosion or any other kind of problems,” Benesch said.

For the second year in a row, more than 300 people—many from non-scientific backgrounds—tested, photographed and recorded various data relating to the area’s water quality. Although the results aren’t yet analyzed, if they are anything like last year’s, the second annual Snapshot Day should provide scientists and officials with some interesting information about the health of the watersheds and their ecosystems.

Last year, volunteers collected water samples and measured water clarity in 44 locations. This year, the group expanded that effort, more than tripling the number of sites tested. Part of the reason for the quick expansion was last year’s success in finding areas to focus on.

Fecal-coliform bacteria may not be a widely known term, but one of the more common forms it can take, e. coli, is. More than 18 of the 44 tested sites had some form of fecal-coliform bacteria, usually found in mammal excrement, present last year. And of those 18 sites, four had levels of fecal-coliform bacteria that exceeded 40 units per 100 milliliters of water. Those levels are high enough to cause some concern. One site, Hatchery Creek at Star Harbor, had levels exceeding 700 coliform units per 100 milliliters of water.

Lovina New, of the Washoe-Storey Conservation District, said the high fecal-coliform levels had been corrected in one area where raw sewage was found being dumped directly into the water system.

“There were two areas where we found unexpected fecal coliform,” New said. “We were able to correct one of the problems. We are still trying to find the source of the other one.”

While detecting problems along the watershed is part of the focus, the overall health of the water system is the primary focus of Snapshot Day. Standing in water past his ankles, Mark Walker said that the information would provide people with an idea of what the water quality is like.

“One of the things we do with the data is look at nitrogen levels, phosphorous levels and total dissolved-solids levels,” Walker said. “It’s important because it gives people an idea of how much substances or sediment loads are in the water. It can give people a sense of how [high] each tributary’s nutrient levels are.”

The nitrogen and phosphorous levels are important because they relate to how much algae is growing in a certain area. Both elements stimulate algae growth, which can get out of hand and cause poor water clarity and quality.

High levels of phosphorous have been identified in Lake Tahoe, and that’s a primary reason why water clarity in the lake is diminishing. Increasing nitrogen levels also take some of the blame for Lake Tahoe’s water clarity, as nitrogen encourages the growth of phytoplankton, a microscopic, single-cell algae that gives water a green tint.

The Truckee’s oxygen levels ranged from four to 10 milligrams per liter. Anything at five milligrams per liter or below is considered dangerous for aquatic life. Although most test sites were OK, six sites dropped below the desired average of 6.5 milligrams per liter. Three of those sites were at five milligrams or lower, meaning aquatic life was in danger in those areas.

Since levels of elements can rise or fall in just a day, Snapshot Day 2002 gives people a look at a point along the watershed only for that moment in time, like a photograph. But when compared with future results, the information could provide people with a long-term look at the Truckee River and Lake Tahoe watersheds. Trends could show areas where more work is needed to restore the ecosystem.

Snapshot Day also gives a starting point from which to work for future maintenance of the watershed. The watershed characteristics can be used to set future management goals for the Truckee River and Lake Tahoe.

New said that Snapshot Day 2002 is part of a national effort to make people more aware of their watershed quality and promote environmental awareness in the community.

“It’s a national program where citizens monitor water quality," New said. "It sort of corresponds with National River Cleanup Week, but we did it a little earlier because we wanted to catch the runoff. We didn’t to go to a bunch of dry creek beds."