Case Studies
UMI TRASHCAT™ Helps Reduce
Colorado River Pollution

How much gunk is too much? River authority to take stock 
of a dirty problem - UMI TRASHCAT™ helps reduce Colorado 
River pollution

TRASHCAT™ Model MS8-1500A 
used to help reduce Colorado River pollution

Rain that does so much good for crispy-brown plants has washed
a surge of pollution, from pesticides to heavy metals, into the 
Colorado River from city pavement. It happens after almost every 
downpour. Combine that with the 4,120 pounds of treated sewage that 
Austin injects into the river every day, and the result is persistent, 
sometimes heavy damage to the Colorado River. Yet nobody knows 
exactly how bad it is. Worse, nobody knows the point at which 
Austin's pollution would cause significant, perhaps catastrophic, 
damage to the river.

The same is true for the hundreds of other communities, businesses 
and recreation sites that pollute the waterway.

Uncomfortable with that level of ignorance, the Lower Colorado River 
Authority expects to spend at least $5 million on an ambitious study 
of pollution sources along 1,370 miles of the Colorado and its tributaries 
and lakes. That will provide the ultimate in regulatory ammunition -- 
a model that can predict how much pollution is too much for a healthy 
river.

"The river is getting to be more and more stressed," said
Joe Beal, LCRA general manager and the driving force behind the 
modeling project. "It's important that we predict ahead of time what 
man's actions are doing to the river."

This week's events provide a striking example. Three days of rain 
have left the river muddy-brown with dirt, sediment and trash -- and 
the high bacteria levels that usually result from heavy rainfall. 
Runoff from streets, yards and construction sites picks up debris 
and ultimately carries it into the river.

"If there's a lot of trash out on the streets, it becomes pretty 
unsightly," said LCRA spokesman Bill McCann.

Every other month, the LCRA analyzes water from 66 sites 
for pollution, bacteria, oxygen levels and other important factors.

Scientists also collect fish, bugs and plants twice a year in an 
underwater census of pollution-sensitive life. If a fish such as the 
blue sucker is on the decline, for example, it's a good bet that 
dissolved oxygen levels are down because pollution is up.

Unfortunately, the tests detect problems only after the river is fouled.

Over the next five to eight years, the LCRA will compile data on 
river life and pollution sources, creating a series of mathematical 
models for the stretch of river from above the Highland Lakes to 
Matagorda Bay in the Gulf of Mexico.

The model will predict daily pollution loads -- including natural 
sources such as deposits of salt or sulfate-producing gypsum -- 
and measure, for example, the impact of converting raw land 
into a feedlot, subdivision or manufacturing plant.

"It's extremely ambitious and extremely commendable," 
said Raj Bhattarai, wastewater regulatory manager for Austin, 
the largest discharger of treated sewage into the Colorado River.

"It will only improve our understanding, so if we need to do better
(at the treatment plants), we are certainly committed to doing 
better," he said.

Sewage, spills and kills

Austin's treatment plants clean sewage far beyond what is 
demanded by Texas, earning raves from the LCRA and state 
regulators.

It's a far cry from the mid-1980s, when the Colorado River was 
Austin's outhouse. An overwhelmed sewage system spewed a 
stinking, polluted mess into the river. Water turned yellow-green 
with slimy algae, fish developed skin lesions, and 15 miles of river
below Austin were declared unsuitable for fishing and swimming.

"It just killed the river for many miles downstream, to Bastrop 
and below," Beal said. "Even cows wouldn't drink the water."

Utility veterans remember it as the time of spills, chills and fish 
kills. Bastrop sued. The attorney general sued.

Austin learned a harsh lesson, spending $400 million to improve 
its treatment plants, and the results are telling. Austin is the state's
only large city whose downstream water is designated as 
"exceptional aquatic habitat" -- the Texas Natural Resource 
Conservation Commission's highest rating.

State permits require Austin to maintain that exceptional rating by
cleaning its sewage to a certain standard. The city exceeds that
standard and plans to continue the high level of treatment, 
Bhattarai said.

An example of Austin's efforts is its handling of organic matter, which 
can destroy a water system by using up too much oxygen. State 
permits allow Austin to release 10,842 pounds of organic matter a 
day. Over the past year, the three plants averaged 1,600 pounds a 
day, or 15 percent of permitted levels, city figures show.

Still, it's impossible to hide the effect that 657,000 residents have on 
the river. And Austin's sewage plants aren't alone -- just in Travis 
County, 44 other cities, utilities or industries discharge wastewater 
into the Colorado.

Several trends are being watched downstream of Austin, including:

* Phosphorus levels. They have been rising steadily since a rapid 
decline in 1992, when the city banned phosphate detergents. 
Phosphorus from human waste can lead to suppressed oxygen 
levels in water. Austin's sewage plants remove only about one-third 
of the chemical.

* Nitrate levels. They also are rising, and although levels are typically 
well below federal safety limits of 10 milligrams per liter, a reading of 
9 milligrams was once measured near Bastrop. High levels of nitrates 
can cause human birth defects and lead to reduced underwater 
oxygen.

Austin's growing population will increase its releases of treated 
effluent. That's one reason the LCRA project will pay close attention 
to certain indicators below Austin -- nutrient and oxygen levels, 
ammonia counts and the like, Beal said.

If the cumulative effect of a certain pollutant is harm to river habitat, 
advance warning is essential because it takes years to upgrade 
treatment plants.

"We are going to work with Austin, not against them, to help them 
take timely action to protect the river," said Dennis Daniel, director of 
the modeling project.

Rainy-day blues

If treatment plants and industry were the only polluters on the river, 
protecting the water would be pretty easy.

But as seen this week, rainfall also adds harmful pollutants. Animal 
waste, pesticides, fertilizers and oil products are washed from city 
streets and farmland, but even undeveloped land adds fecal matter, 
leaves, dirt and dead animals.

"When that stuff washes off, it starts to break down and uses up the 
oxygen," said Dave Bass, an LCRA aquatic scientist. "That's when 
you get, in extreme cases, fish kills and foul odors."

Fortunately, the slugs of dirty water tend to wash quickly downstream. 
A heavy rain in Austin usually will lower the river's oxygen levels for 
about a day, Bass said.

The problem is determining at what point dirty stormwater, when 
combined with the daily pollution from sewage plants, begins to 
degrade the river's ecosystem.

The LCRA modeling project should provide answers that will help 
cities decide the best pollution approach -- upgrade sewage plants, 
or try detention ponds and other strategies to capture stormwater.

Austin is developing its own pollution modeling project (its data will 
help the LCRA's efforts) and studied a recent 1 3/4-inch rainfall. On 
heavily urbanized Shoal Creek, 69 pounds of nitrogen washed into 
Town Lake. But relatively undeveloped Bear Creek, on a similar-
sized watershed south of Austin, produced only 9.2 pounds of 
nitrogen.

Nitrogen, often found in fertilizers, also leads to depleted oxygen 
levels in water.

Although it's hard to control and difficult to predict, this type of 
pollution is largely preventable, whether you live in the city or along 
the Highland Lakes. Don't dump used motor oil. Don't use too much 
fertilizer or pesticides. Don't rake grass clippings into the gutter. 
One way or another, much of it ends up in the river -- and in drinking 
water supplies.

'Pretty sure' won't cut it'

The ultimate goal of the LCRA's modeling project is knowledge. The 
agency hopes its data will influence state regulators, city decisions 
and its own management of the river.

"Now we can say, 'We're pretty sure that's what's going to happen,' 
" Bass said. "But when you're making (regulatory) decisions, 'pretty 
sure' doesn't cut it."

"It's better science," said Ken Manning, manager of environmental 
policy for the LCRA. "What we're after is providing better information 
for policy and management decisions. What should nutrient 
standards be for Lake Travis? We don't really know."

The Texas Natural Resource Conservation Commission expects to 
benefit from the sustained, focused study that only a river authority 
can provide. "As long as the science is verifiable and is giving us 
accurate information . . . then we certainly can go along with that," 
spokesman Dick Lewis said.

You may contact Chuck Lindell at clindell@statesman.com or 
(512) 445-3627.

On the Web
* Information on pollution and protecting the Colorado River is at www.lcra.org/lands/wrp.
* Water quality and quantity information is http://waterquality.lcra.org

SOURCE: The Austin American-Statesman Archives

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