Scientists keep eye on runoff from storm water

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LANL: Authorities monitor water quality in Rio Grande

By The Staff

With the Las Conchas Fire last year, most were fearing the worst when it came to storm water runoff.

It certainly was bad but not as bad as it could have been, said Ralph Ford-Schmid from the NMED Department of Energy Oversight Bureau.

They definitely felt it at Bandelier National Monument as one thunderstorm caused a massive flow down Frijoles Canyon. Sandbags saved the visitor’s center from extensive damage.

There were floods at Santa Clara Pueblo, Dixon’s Apple Orchard, Peralta Canyon, the Valles Caldera and another that caused a flash flood near El Rancho.

In all, there were 13 flood events, Ford-Schmid said.

And how would he classify last year’s events?

“I think it would be light to medium,” Ford-Schmid said.

And with monsoon season approaching, there could be even more flash floods, Ford-Schmid said.

“I anticipate it being busy,” he said.

But with the floods came another concern — water quality.

Ford-Schmid made a presentation a couple of weeks ago at Santa Fe Community College as he talked about the fire impacts on water quality in the Rio Grande River last year.

There were concerns in Santa Fe and Albuquerque after the fire burned more than 150,000 acres and the resulting flash flooding from the burned watersheds had the potential to significantly impact water quality in the Rio Grande.

“For one thing, we were surprised at how little suspended sediment there was,” Ford-Schmid said. “We did expect a greater increase but the increase was not that significant.”

Since Santa Fe and Albuquerque draw water from the Rio Grande, the New Mexico Environment Department (NMED) and the City of Santa Fe Buckman Direct Diversion (BDD) continually conduct extensive storm water quality monitoring at the BDD intake.

In his report, Ford-Schmid cited that NMED has been monitoring storm water quality in the Rio Grande at the Otowi Bridge on San Ildefonso Pueblo lands, the BDD intake and upstream of the intake for the City of Albuquerque San Juan-Chama Drinking Water Project since 2009 and in 2011.

“We collaborated with the BDD to install five ISCO automatic samplers triggered by telemetry based on flow from lower Los Alamos Canyon and/or a 500 CFS increase in flow in the Rio Grande,” Ford Schmid wrote. “Samples were collected during 13 storm flow events at the BDD intake, three flow events at the Otowi Bridge and three flow events above the City of Albuquerque San Juan-Chama Drinking Water Project intake during 2011.”

Then Ford-Schmid got really technical.

“In most cases, multiple samples were collected during the storm hydrograph. Water samples were analyzed for suites of filtered and unfiltered radionuclides (gross alpha/beta, Pu-239/240, Pu-238 (plutonium), Am-241(americium), Sr-90 (strontium), U-234, U-235, U-238 (uranium), Cs-137 (cesium) and other gamma emitting isotopes), 23 metals plus cyanide (filtered and unfiltered), polychlorinated biphenyl, dioxin/furan, total organic carbon, perchlorate, particle size, carbonate and bicarbonate and SSC,” Ford-Schmid wrote. “Suspended sediments were separated from the water and analyzed for the same radioisotopes, 23 metals plus cyanide, total alkalinity and carbonate/ bicarbonate alkalinity. Box and whisker plots are used to display data and comparisons to applicable water quality criteria are provided.  Results for suspended sediments are compared to previously reported background benchmarks.”

Ford-Schmid some of the radionuclides had elevated levels during the testing at that time, the EPA requires an average over a 12-month period.

“Certain samples were up,” Ford-Schmid said. “But they were below the standards in all the radionuclides.”
LANL, meanwhile, also has a substantial storm water monitoring plan and it was put to a good test following the Las Conchas fire.

Storm water samples were collected from runoff events at gauge stations located to represent water quality for runoff flowing onto and off of laboratory property. Stations included in this monitoring plan included stations upstream and downstream of the lab.

Crews obtained the samples from the automated samplers, typically the day after the runoff has ended.

The sampling plan was developed to provide fast turnaround data analysis at offsite analytical laboratories. The current estimate is that results from a runoff event will be publicly available in approximately 15-20 calendar days.

Samples were processed and shipped with the highest priority. According to the LANL website, stormwater data required a large number of analyses to be executed on samples (more than for air), and the laboratories that do this were located out of state. Labs analyzed the samples as fast they could and LANL personnel will be monitoring and assisting daily to ensure the samples have top priority.

However, some analyses have a minimum time requirement due to the need to prepare the sample (settle the water to remove silt, sample digestion, etc.). When data are available, the sample results will be sent to LANL electronically. Data is then posted on a new website: intellusnm.com/.

Last year, LANL’s Danny Katzman made a presentation to the New Mexico Community Foundation concerning contaminants in the Rio Grande, he cited two different reports.

Kerry Howe (2008) concluded about contaminants in the Rio Grande: “concentrations in the river (raw water) are nearly always below regulated levels” and “evidence of increased cancer risk from drinking treated Rio Grande water does not exist”

ChemRisk (2010) concluded: “chemical and radionuclide levels in the Rio Grande are below acceptable drinking water standards, and/or occur naturally in the environment.

LANL contributes very little, if any, chemicals and radionuclides to the Rio Grande during normal river flow conditions” and “storm water discharge from LANL does not pose a health risk.”

Lab staff and workers have also made a number of flood mitigation efforts around the DOE property since the Cerro Grande Fire in 2000, putting in a number of erosion controls at Los Alamos and Pueblo Canyons, including rock check dams, surface roughening, water bars and weirs.

The lab also took actions when it came to sediment transport. In Pueblo Canyon, they planted 6,000 willows and DP/Los Alamos Canyon, they excavated and enhanced the weir. In both areas, they made improvements to the grade control structure.

“Los Alamos Canyon was not burned as bad as Cochiti,” Ford-Schmid said. “And there are less areas of less denuded watersheds. Los Alamos Canyon also has an advantage over the canyons in that there is a reservoir and that can act like a surge tank. The lab has also done a tremendous amount of work in their mitigation efforts.”