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EPA to look at Tahoe drainage systems

Tahoe Daily Tribune article, copied from Wednesday, November 2, 2005
EPA to look at Tahoe drainage systems
By Amanda Fehd

Homeowners and businesses in Tahoe could be installing drainage systems regulated by the U.S. Environmental Protection Agency for health safety reasons - and not know it.

Representatives from the EPA, Tahoe's planning agency and Nevada's environmental protection agency met by conference call last week to discuss whether drainage systems used in Tahoe fall into a category EPA alleges has the potential to contaminate groundwater. No decision was made.

A variety of drainage systems are used in Tahoe to comply with a Tahoe Regional Planning Agency ordinance requiring most property owners to install devices to catch rain and snowmelt.

Called stormwater best management practices, or BMPs, the systems are intended to prevent soil erosion.

Most not a concern

While most of the drainage systems in Tahoe are not a concern, some may be classified as Class V wells, according to Elizabeth Janes at EPA's Region Nine groundwater office in San Francisco.

Tahoe's rain and snowmelt, called stormwater, is generally very clean, diminishing risk of contamination, according to Lahontan Regional Water Quality Control board, which regulates water quality at Lake Tahoe.

However, certain drainage systems would allow any contaminants, or spills of auto or lawn chemicals, to more easily enter groundwater, according to EPA.

EPA requires inventory information from property owners who install Class V drainage systems because of their alleged potential to contaminate groundwater.

Users must also agree not to allow any substances that are threats to drinking water to enter the systems.

EPA's list of threats to drinking water includes chemicals used in household cleaning, lawn and auto care and is available at www.epa.gov/safewater/mcl.html#mcls.

The worst kind of Class V well is a drilled hole allowing water directly down to the water table. The technique is not used in Tahoe but has been standard construction practice in other parts of California, Janes said.

But Class V wells can include many other types of underground drainage systems, according to EPA.

Much of South Shore gets its drinking water only from groundwater, while the lake supplies drinking water to most of the Nevada side. Drinking water is constantly monitored for purity.

No decision yet

EPA is not ready to make a determination on designs for residential or commercial BMPs in Tahoe before taking a closer look at them, Janes said.

"We all agreed we need to sit down and look at these on location," said Russ Land, supervisor of the groundwater protection office of the Nevada Division of Environmental Protection, Janes's Nevada counterpart. NDEP provides funding for TRPA's residential BMP retrofit program.

Based on his limited review of residential BMP designs in TRPA's contractors handbook, Land said none fit the definition of a Class V well.

EPA Region Nine was not so sure, Janes said.

The three agencies met after inquiries to EPA from the Tahoe Daily Tribune about whether the Class V wells were used in Tahoe. Area engineers raised the issue with the Tribune.

While Birgit Widegren, head of TRPA's soil erosion team, said it has not been interpreted in the past that Tahoe's designs qualify as Class V, EPA representatives were not certain.

Engineer approved

All Tahoe BMP designs are approved by a state engineer, according to Erik Larson, program coordinator for the Tahoe Resource Conservation District, which provides information to owners of homes where BMPs are installed.

Measures are in place to protect groundwater in Tahoe, according to Widegren. Properties expected to release pollution into rain water or snowmelt, like an auto station, are required to treat it before it is allowed to enter the ground.

TRPA's approach to BMPs is very conservative, Janes said. "They aren't ignorant of the vulnerability of their groundwater."

TRPA's BMP ordinance is aimed at reducing soil erosion, one of the main factors in Lake Tahoe's declining clarity.

"The fundamental concept of keeping soil on property is sound and how we do it may evolve over time," said TRPA spokeswoman Julie Regan. "It's a collaborative process and we will be making sure we are all in agreement."

Homes less risky

Residential properties are less of a risk to groundwater than commercial properties, Janes said.

"EPA does not want to discourage anyone from implementing their residential stormwater BMPs," said Janes. But she cautioned property owners to be responsible about chemical use such as fertilizer, pesticides, herbicides and auto chemicals.

"What you pump into the ground ends up somewhere," she said.

A fact sheet from EPA says there is concern "there may be a dramatic increase in the use of Class V wells as a (BMP) to dispose of stormwater. Infiltration through stormwater drainage wells has the potential to adversely impact [underground sources of drinking water].

The runoff that enters the stormwater drainage wells may be contaminated with sediments, nutrients, metals, salts, fertilizers, pesticides and microorganisms."

The fact sheet was put out in response to construction practices in Modesto, Janes said. It is available at www.epa.gov/safewater/uic/pdfs/fact_class5_stormwater.pdf.

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