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Eutrophication is the natural process by which nutrients
from sediments are carried in runoff to surface waters where
they provide nourishment for naturally occurring algae. Increased
human activity nationwide has increased the amount of nutrients
reaching water bodies, where they stimulate algal growth and
decrease water clarity. The decomposing algae take up oxygen,
which threatens fish and other aquatic life, and the algae
itself inhibits human use and enjoyment of rivers, lakes,
and streams.
Efforts to control point and nonpoint nutrient sources have
been ongoing since the mid-1980s, although with moderate success.
The 1972 Clean Water Act lays out a regulatory process for
controlling point sources through the establishment of TMDLs
(total maximum daily loads), but the TMDL process does not
extend to non-point sources, including OWTS, agriculture,
and urban runoff.
The challenge is exacerbated where jurisdictions overlap.
Lake Tahoe, which is losing its famous clarity due in part
to excessive algal growth, is split by the California-Nevada
state line, while the waters of Lake Champlain cross the US-Canadian
border. The Chesapeake Bay Watershed includes parts of five
states plus the District of Columbia, and what happens on
the Clark Fork River in Montana affects Lake Ponderay in Idaho.
Experience also demonstrates that initial expectations that
controlling the point sources would get us where we want to
go have proved unrealistic. The Tahoe Basin exports all its
wastewater to Nevada and still algae persists. The sophisticated
watershed modeling that is a hallmark of Chesapeake Bay clean-up
efforts pegs agriculture as the source of 50% of the nutrients
entering the bay. Septic systems currently account for only
4% but are nonetheless significant because they’re attached
to waterfront homes.
Evidence from projects nationwide suggests standards are
best set according to local conditions, with attention given
to variations within and among ecosystems, and the most productive
approach appears to be one of flexibility, cooperation and
collaboration—and maintaining a well-informed focus on
socio-political variables.
Safeguarding the Estuary
The Chesapeake Bay has the highest land-to-water ratio of
all the world’s estuaries. Its 64,000-square-mile watershed
is currently home to 16 million people and the human population
is projected to reach 18 million by 2020. The bay itself is
approximately 4,400 square miles and is shallow, on average
21 feet deep. Groundwater contributes 54% of the total annual
flow of streams in the watershed, and a recent USGS study
established that the groundwater nitrate load contributes
48% of the total annual nitrogen loading of streams entering
the bay. Groundwater enters the Chesapeake as base flow to
streams and rivers and as discharge from shallow aquifers
directly into the bay and its tidal tributaries. Four hundred
sewage treatment plants discharge effluent into the bay; currently
less than a quarter utilize nutrient reduction technology,
and yet point sources are responsible for only 20% of the
285 million pounds of nitrogen and 19.1 million pounds of
phosphorous the bay sustains annually.
The effort to clean up the Chesapeake began in earnest in
the early 1980s with the formation of the Chesapeake Bay Program.
Twenty years of good intentions followed by frustration, which
culminated in a lawsuit brought by the state of Virginia,
led to the Chesapeake 2000 agreement in which the five watershed
states and the District of Columbia committed to correcting
nutrient and sediment-related problems in the bay and its
tributaries sufficient to remove the estuary from the EPA’s
list of impaired waters by 2010. The pact featured the ground-breaking
strategy of bringing the states and the EPA together at the
start. “The idea,” says Kelly Shank, tributary coordinator
for the EPA’s Chesapeake Bay Program field office, “was
to develop the first ever regional water quality criteria.”
“What we did is an alternative to developing TMDLs,”
explains Chris Connor, spokesperson for the Chesapeake Bay
Program. “We developed a cooperative partnership. In
the past we had standards, but they were the same for the
entire bay—top to bottom, east to west. Our goal in this
effort was to effectively zone the bay. This entailed developing
a new set of designated uses based on the bay’s living
resources.”
A critical element of the Chesapeake 2000 effort was that
it included Bob Koroncai, regulatory manager for EPA Region
3, who brought a regulatory perspective to criteria-setting.
“Previously,” says Koroncai, “the states had
been working with “cookie-cutter national standards that
didn’t work for the bay.”
The resulting habitat zoning, which took three years to complete,
established nutrient loads for five zones based on their designated
uses among the bay’s aquatic species. The zones include
shallow-water bay grass, open-water fish and shellfish, spawning
and nursery areas, deep-water seasonal fish and shellfish,
and deep-channel seasonal refuge. Once the zones were established,
modeling was used to determine nutrient reductions required
to sustain these habitats. This produced a cap of 175 million
pounds of nitrogen annually (a reduction of 110 million pounds)
and 12.8-million pounds of phosphorous (a 6.3-million-pound
reduction). The pollution cap load was then distributed between
nine different watershed basins. To meet their respective
loads, the states have committed to developing statewide tributary
strategies to be implemented by local jurisdictions.
“We’ve done virtually almost all the work for a
TMDL, which to my way of thinking is a pollution budget,”
says Koroncai, “but instead of this being top-down heavy,
we built it together. And, as a result of this cooperative
effort, the states, which are being required by EPA to establish
individual nutrient standards, have had their standards approved
in record time.”
Koroncai says three major factors were critical to the success
of the Chesapeake partnership: 1) the large-scale cooperative
stakeholder effort dating back to1987, which included both
the regulated community and environmental groups; 2) instead
of the A-B-C step-wise TMDL approach, water quality criteria
and nutrient caps were developed concurrently; and 3) the
EPA was included as a partner from the beginning.
“All of our decisions were based on the assumption that
the states would adopt water quality standards consistent
with these decisions. This turned out to be the case. We had
everything wrapped up by summer 2005.”
As the core to their tributary strategies, the states have
agreed point sources will be regulated through nutrient limits
established in NPDES permits. Shank reports that in the nonpoint
arena (where a fix will likely cost $20–$30 billion)
the states are relying on agriculture to get them two-thirds
of the way toward their goals. “Agriculture is a big
source,” says Shank, “and one of the most cost-effective
ways to reduce loading. Controlling urban and stormwater runoff
is not currently seen as important to getting us to our cap.
But the fact is, given the population growth in the watershed,
to stay there over the long haul, it’s going to be critical.”
Shank says the EPA will be depending on an extensive, integrated
system of monitoring to assure the 2010 target is met. The
effort will include the states, the USGS, universities, local
agencies, and the EPA, and the goal is to double current watershed
monitoring stations.
Do the states feel comfortable with the tributary strategies?
“Absolutely not,” says Shank, “But what they
have is more flexibility to work with each other. They can
pick and chose what they’re going to do. The TMDL process
was not set up for this kind of regional approach.” Shank
thinks one of the plan’s biggest challenges will be building
local support for nutrient reduction levels that have already
been established. “In Cooperstown, NY, for example, how
many people have a stake in the Chesapeake Bay?”
Voluntary Controls Along the Clark Fork
Collaborative compliance in anticipation of government regulations
has gained a footing in Montana’s 25,000-square-mile
Clark Fork River Watershed.
“What the signatories to the Voluntary Nutrient Reduction
Program (VNRP) did back in the ’90s,” says Will
McDowell, VNRP coordinator for the Tri-State Water Quality
Council in Missoula, MT, “was realize there was a strong
possibility that government, state government in this case—with
possibly some implications from the EPA—was going to
continue to constrict their wastewater discharge permits for
nutrients. What they decided to do, in a very fortuitous alignment
of interests and personalities, was to take the initiative.”
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PHOTO: VADA
YOON |
| Erick Stein and Liesl Tiefenthaler
of the SCCWRP take water samples from Cold Creek in the
Malibu Creek watershed. |
Five primary organizations were in some way dischargers or
responsible for discharge into this 200-mile-stretch of the
Clark Fork River—the cities of Missoula, Butte, and Deer
Lodge; a commercial paper mill; and the county of Missoula,
which regulates OTSW—by the mid-1980s considered a source
of nitrogen in the river. As part of its commitment to nutrient
reduction, the city of Missoula, which is rapidly expanding
into outlying areas (11,000 septic systems have been installed
in the Bitterroot Valley in the last 20 years), undertook
a study to consider whether some of this growth should be
sewered. Monitoring established both nutrients and bacteria
in shallow groundwater, and the city opted for sewers in densely
populated areas.
Concurrently the city’s wastewater treatment plant underwent
an $18 million upgrade that reduced nitrogen in its effluent
from 23–30 mg/l to10 mg/l. The paper mill also decreased
the nutrients in its river discharge while Butte and Deer
Lodge established land application programs to dispose of
their wastewater effluent.
“When they drew up the VNRP agreement in 1998,”
says McDowell, “it was, for all intents and purposes,
a TMDL. But instead of government coming in to do a study
and telling them what their loads would be, local government
and private industry basically did the allocations themselves.
They’d all decided they needed to reduce their nutrient
discharge; the question was how much?”
Allocations were decided using relatively simple hydrologic
and water quality models. The state gave the signatories 10
years to bring the algae under control and agreed to no additional
government constraints during that period. Today they’re
well on their way to meeting their targets, which are pretty
strict—0.3 mg/l for nitrogen and 0.02 mg/l for phosphorus
in some areas, 0.39 mg/l in others. The agreement expires
in 2008, when the standards will become mandatory.
McDowell has subsequently embarked on a study of the impact
of OWTS on surface waters, with the goal of influencing local
government to evaluate where they allow septic systems to
be sited. “Most of the literature addresses the impacts
on groundwater and on human health,” say McDowell. “We
wanted to highlight the potential impact on surface waters
and the health of aquatic species. Based on what we found,
we’re suggesting governments take a more informed look
at the kind of septic systems they allow in areas where growth
tends to be near vulnerable surface waters like high-quality
rivers and lakes—and at what density.”
Asked what he’d do differently, McDowell admitted to
two “conundrums. Number one, you can’t relate algae
growth as closely to nutrient concentrations as you would
hope or expect. A lot of other factors come into play, and
they’re out of your control. In Montana’s rivers,
for example, the amount of algae growing on the river bottom
is highly related to the previous five to 10 years of floods.
There are also sunlight and the flow of water in the river
to consider.
“My other conundrum is much more of a social issue.
At a certain point,” McDowell says, “population
growth overwhelms the effects of best management practices.
Any human family is going to generate nutrients in the course
of their normal daily activities, from fertilizing the lawn
to flushing the toilet and running the garbage disposal. The
question is how much human population density can you build
into a watershed before you overwhelm the limited capacity
of the system?”
Keeping Lake Tahoe Blue
West of Montana in the Lake Tahoe Basin, the focus is on stormwater,
but the approach is also collaborative, in this case between
the Lahontan Regional Water Quality Control Board, the Nevada
Division of Environmental Protection, and the Tahoe Regional
Planning Agency (TRPA).
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PHOTO: WILL
HART, COURTESY LAKE TAHO VISITORS AUTHORITY |
| Fannette Island in Emerald Bay
is Lake Tahoe's only Island. |
Lake Tahoe is located near the crest of the Sierra Nevadas
at an altitude of 6,225 feet. Two-thirds of the lake and its
watershed lie in California, a third in Nevada. The lake covers
200 square miles, which is one-fifth of its watershed, and
reaches a depth of 1,465 feet, making it the tenth deepest
lake in the world. Known for its clarity and striking blue
color, Lake Tahoe has been awarded EPA status as an Outstanding
Natural Resource, its highest standard of protection. It is
a matter of no little concern, then, that the lake’s
famed water clarity has been decreasing approximately a foot
a year for the last 30 years, a time-frame that also coincides
with rapid urbanization in the Tahoe basin. There is no agriculture
in the basin, but atmospheric deposition is a significant
nonpoint nutrient source, along with urban runoff, groundwater,
and soil erosion. And although 61 tributaries feed the lake,
the current objective is to control stormwater in what Dave
Roberts of the water quality control board characterizes as
intervening zones, i.e., natural or armored channels that
drain directly to the lake.
Fortuitously, the effort coincides with an update of its
regional plan being undertaken by TRPA. The bi-state compact
that created the agency was sanctioned by congress and signed
during California’s Reagan administration to coordinate
control of development around the lake. The agency does not
have police powers but it does have regulatory control, and
the plan is that whatever water quality standards are developed
for the lake will be reflected in the agency’s codes
and ordinances. Or as Roberts describes it, Pathway 2007 will
effectively be the implementation plan for the TMDLs that
are expected to be developed by winter 2006–2007.
With its two partners, TRPA is coping with a variety of factors
that have affected lake water quality and general degradation
of the natural environment in the basin, including increasing
resident and tourist populations, air pollution, soil erosion
and habitat destruction, road construction and maintenance,
and loss of natural landscapes to detain and infiltrate rainfall
runoff.
“We’re fortunate we’re not arguing about whether
or not there’s a problem,” says Roberts. “There’s
a lot of public support here to protect the lake. I think
that’s 99% of the challenge with TMDLs—trying to
get people to agree there’s a problem. Originally, we
hoped that diverting the sewage would take care of it and
we basically ignored stormwater. That’s been the facility
of the TMDL program. We went aggressively at those point sources
and did some arm waving at nonpoint sources, which really
has us in a pickle now. What you need is a combined watershed
approach.”
Lake Tahoe is impaired by periphyton, which, while not historically
found in the lake, has become a recreational and aesthetic
issue. Phytoplankton was considered responsible for the lake’s
clarity loss until modeling by the University of California,
Davis indicated that 60%–70% was the result of fine particulates
(0.52–2 microns). In Roberts’s view the three have
to be dealt with collectively. “There’s a dynamic
interaction and all three have to be reduced. The good thing
is strategies for controlling sediment are similar to those
for nutrients.”
Following the lead of the Chesapeake Bay Program, Lake Tahoe’s
water quality advocates are depending on models developed
by Tetra Tech Inc. to get a handle on the complex human-environmental
interactions affecting the lake. Although the basin has been
working on water quality for 20 years, there has never been
a target for nutrient or sediment load reduction. For years,
nitrogen was the lake’s nemesis, but today the lake is
phosphorus limited, and Larry Benoit, TRPA’s water quality
program manager, says the agency is waiting on modeling results
to determine the extent to which control measures will be
needed. Given that stormwater is a prime target, land use
and impervious coverage layers of Tetra Tech’s watershed
model are critical. Satellite photographs of impervious surfaces
throughout the basin have been combined with the model’s
land-use layer to determine what part of a property designated
for a particular use is actually developed.
Although TMDLs are not enforceable on private property, Benoit
says one of TRPA’s strengths is its regulatory powers,
which allow it to regulate nonpoint sources through its water
quality management plan. Currently the agency is requiring
not only BMPs for new construction but retrofits on existing
development.
Monitoring the results of load reductions will be a question
of long-term funding. Up to this point it’s been done
by individual small contractors, consultants, and some local
jurisdictions, with the main focus on tributary streams. “Monitoring
will be critically important,” says Benoit, “since
our aim is adaptive management, where we can make adjustments
if we’re not meeting our goals. The intent is a funded
monitoring system ready to go for 2007.”
Successes so far? Maintaining interest and keeping people’s
attention, says Benoit, plus the amount of restoration and
retrofitting that’s already been accomplished. “We
used to see plumes out in the lake. Not so much anymore. Another
success is that there are so many local jurisdictions in both
states really focused on improving the situation.”
Challenges? Roberts thinks it critical to get data sets in
order before you start modeling. “Be aware of what kind
of data you have and the quality and accessibility. We spent
a great deal of time on land-use layers because we were somewhat
naïve. We discovered that summaries of BMP effectiveness
were scattered among numerous different agencies, and it took
a lot of leg work to try to pull those together. It turned
out nobody was keeping track of what BMPs have been deployed,
where and what type.”
Establishing the Background
Data of another sort is on the mind of Eric Stein of the Southern
California Coastal Water Research Project Authority (SCCWRP).
“When it comes to setting water quality standards,”
says Stein, “we have this persistent question of the
natural background levels for a whole range of constituents
in our water courses.” To get a handle on this question,
Stein is heading up a $1 million effort monitoring natural
nutrient levels in southern California streams from Ventura
to San Diego. The two-year study is funded through public
funds and a grant from the EPA.
In addition to setting background levels, Stein’s work
is designed to provide data that will allow public policy
makers to account for natural loads when they model or set
nutrient load allocations. The unique approach involves hands-on
monitoring of 22 sites in undeveloped watershed segments.
Samples will be collected during rainfall events and post-storm
runoff and will include real time sampling over the course
of a storm.
“One of the things that makes this study different is
that most research looks at water quality during dry weather,”
says Stein. “We’re adding the stormwater component
to understand what kind of natural loads are coming down the
stream during and after rainfall. This is important because
most of the loading occurs during stormwater.”
Stein’s researchers take samples hourly during the duration
of the storm, which will allow them to construct a plot of
concentrations versus time. The goal is to assess whether
nutrients are coming out at the beginning of the storm, during
its peak, or during the tailing back end, i.e., up to a week
afterward.
A year into data collection, Stein notes that he’s observed
“a lot more” algae in natural systems than he expected.
Given this anecdotal finding, his monitors are quantifying
the amount of algae they observe and characterizing the composition
of dry season algal communities to determine whether they
change from natural to developed habitat. Stein’s researchers
will also be looking at related factors, such as the general
quality of the habitat, canopy cover, and water temperature
and depth. “When you think about appropriate nutrient
levels and appropriate algae,” says Stein, “you
have to take into account these physical and hydrological
factors as well.”
The project is scheduled to wrap up in spring 2007. Data
and the technical report will eventually be published on the
agency’s Web site.
Confounding Factors in Lake Champlain
A USGS study of groundwater flowing into Chesapeake Bay documented
travel times ranging from 0–5 years to 50 years, which,
as Connor has observed, raises havoc with public expectations
for algae clean-up. Scientists following St. Albans Bay on
Lake Champlain have also been confounded about why algae still
persists given the amount of effort that’s been thrown
at it.
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PHOTO: VADA
YOON |
| Chris Solek measures oxygen levels
as part of biological assessment of streams. |
Half of the state of Vermont drains into Lake Champlain,
which flows north to the Richelieu River and from there into
the St. Lawrence. Some 90 wastewater treatment plants discharge
effluent directly into the lake and OWTS are used throughout
the bay’s watershed.
Using state funds, Vermont has been steadily retrofitting
individual treatment plants to equip them to remove phosphorous
from effluent. “This has been the major success story
in reducing phosphorus inputs into the lake,” says Vermont
state limnologist Eric Smeltzer. Under Governor James H. Douglas,
the state also launched a Clean and Clear Water Action Plan,
which is funding non-point source clean-up, including programs
for agriculture (mostly dairy farms), stormwater, streambank
stabilization, and erosion control on back roads and construction
sites.
Governor Douglas also accelerated the original 20-year schedule
for implementation of the bi-state phosphorous TMDL (0.8 mg/l,
approved by the EPA in 2002), charging local jurisdictions
with doing everything possible to hit the target throughout
the watershed by 2009, when the region will celebrate the
400th anniversary of the lake’s discovery. Among other
categories, the Clean and Clear Water Action Plan includes
$3.5 million to help farmers on such projects as manure management
structures and streambank stabilization; $2.575 million for
buffers along streams; $1.325 million to support conservation
programs in the St. Albans Bay and Missisquoi Bay watersheds;
$1 million for municipal treatment facilities in selected
Mississquoi Bay municipalities; $250,000 for wetland restoration
and acquisition; and at the bottom of the list, $75,000 to
support regional planning for water quality initiatives.
Despite all this, the algae persists in St. Albans Bay. Reviewing
research on the bay, Smeltzer reports that historical analysis
of point and nonpoint sources from 1750–2000 shows a
steady increase in phosphorous loading between 1880 and 1930,
after which loading continued at the sustained rate of 50
metric tons a year for subsequent decades. In1980 a US Department
of Agriculture Rural Clean Water Program project was begun
in the St. Albans Bay watershed to initiate agricultural BMPs
designed to reduce water pollution. Smeltzer reports that
although the $2.2 million program reached 60% of the farms
in the watershed, it did not produce measurable reductions
in phosphorus in the bay.
A 1987 $2.3 million upgrade of the City of St. Albans sewage
treatment plant reduced phosphorous loading from this facility
by 90% and since then the plant has consistently met its phosphorus
concentration limit of 0.5 mg/l—the lowest phosphorous
limit in any treatment plant effluent discharge in Vermont.
In contrast to the point-source success, a 1991 study reported
that two of the tributaries to St. Albans Bay contained the
highest amounts of phosphorous in all of Lake Champlain’s
subwatersheds. One study by the Lake Champlain Basin Program
suggested that land conversion to urban uses could be offsetting
some of the gains made by point source and agricultural nonpoint
phosphorous reduction efforts. (The same study pegged individual
septic systems as contributing less than 2% of phosphorous
loading to the bay, compared to stormwater runoff, which accounts
for under 18%.)
But the bad news is that despite the studies and varied local
and community efforts, phosphorus concentration in St. Albans
Bay has not declined over the past two decades. and phosphorous
levels remain above the Vermont water quality criterion for
the bay. The answer to this perplexing problem, says Smeltzer,
had not been anticipated. Concentrations of phosphorus are
persisting at high levels because phosphorous stored in the
bay’s sediments is being released back into the water
through the process of internal loading. “Shallow lakes
are particularly sensitive to internal loading,” says
Smeltzer, “and the situation will eventually be resolved,
but it will take time.”
What we’re coping with here, says Burlington-based environmental
consultant Don Meals, is “the inertia of natural systems.
It took a long time for the sediment to build up and it’s
going to take a while for it to be flushed out.” But
as both Meals and Smeltzer point out, this lack of progress
in the bay has been frustrating, given high hopes for clean-up.
Sediment research of another type is being conducted by Suzanne
Levine, associate professor at the Rubenstein School of Environment
and Natural Resources at the University of Vermont. Levine
wants a better idea of the historic nutrient levels in the
lake. “I think it’s important to have data that
helps us understand what was going on before there was much
development. What we’re doing is taking sediment cores
and dating them. The pigments in algae are to a large extent
preserved in sediment, so, looking at the pigments in the
various sediment samples, we can get some idea of how abundant
algae was at a given time.” The goal, says Levine, is
to reconstruct the condition of the lake over the last 400
years—and do it in time for the lake’s centennial.
Meals, who has been involved in a number of projects under
the Rural Clean Water Program throughout the country, raises
a question apropos of St. Albans Bay, but which is also critical
to the larger challenge of non-point source control. “There
is an important distinction to be made between documenting
the effect of individual practices and assessing their effects
on a watershed. You can monitor and study individual practices
and document their effectiveness, but it’s a very different
question—and often very difficult to answer—to look
at the total effect at a watershed level of a program that
works with a lot of different landowners in a lot of different
places around a watershed. This is the same question TMDLs
are attempting to address.
“Regarding the projects we did in the 1980s,” says
Meals, “the short, simplified answer to these two questions
is that, yes, in many cases you could identify and document
the effectiveness of individual practices at the edge of a
field or at the farm scale. But it was quite another thing
and very difficult to show an improvement in water quality
at the outlet of the watershed or, much less, in a bay of
Lake Champlain.”
Meals’s comment suggests a fundamental issue attached
to TMDLs: the relative commitment of public resources versus
anticipated gain, which is where researcher Ken Reckhow at
the Nicholas School of Environment and Earth Sciences at Duke
University, and his colleagues at Tulane University and University
of South Carolina hope to provide some guidance. Reckhow chaired
the 2001 National Academy Review of the TMDL program and one
of his recommendations to congress was that states do tri-annual
review of their water quality standards that include “an
honest assessment of the resources citizens are willing to
pay for clean water.”
“Water quality standards have a designated use,”
says Reckhow, which is narrative. And that’s the crux
of the standard—what you want to achieve (fishable, swimable,
etc.). The standards also have a criterion that is sometimes
narrative but oftentimes quantitative, something the state
scientists can go out and measure. Our objective was to figure
out a way to quantify the designated use and then determine
what common nutrient criteria would be most predictive of
that use. We did this through traditional expert elicitation
procedure fairly commonly used in decision analysis. You obtain
the opinion of experts through a series of preparatory material
and then subsequently some questions. We used statistical
methods to determine what among the common, easily measurable
predictor variables or quantities are most predictive of algae-related
water quality problems. This turned out to be chlorophyll
A.”
But the crux of what Reckhow and his colleagues were after
is contained in a decision-making matrix that presents concentrations
of the best predictive criteria along the horizontal axis
and the probability of or risk of non-compliance along the
vertical axis. “It’s not realistic,” says Reckhow,
“to think that the resources are available and the pubic
would want them to be to make an urban stream in downtown
DC fishable and swimable. And yet we’re saddled with
that because the standard says that’s what we must achieve.
And because of this criterion, the water body is viewed out
of compliance and goes on the list for a TMDL.”
Dale Robertson, USGS research hydrologist in Middleton, WI,
has a similar take on the TMDL process. Like Reckhow, Robertson
is also concerned with criteria-setting. “What we’re
looking at is whether you set criteria just based on the biological
response,” says Robertson. “Can you look at the
response and say, ‘OK, what concentrations of nutrients
do you need?’ The ultimate goal would be to use this
information to set up flags when a stream is impaired.”
But the Catch 22, as Robertson describes it, is that while
for some streams in his region the goal would be to reduce
nutrients to reference concentrations before agriculture,
the designated use of that stream is to drain an agricultural
area.
“What we felt at the time of the TMDL report,”
says Reckhow, “and what we are still continuing to work
on is adaptive implementation of TMDLs. You learn while you’re
doing. The science is never going to be absolutely certain,
which means you’re going to get it wrong sometimes. So
you need to build into a program some flexibility to ultimately
get closer and closer to what the public wants. Section 303
of the Clean Water Act has the flexibility for a continuous
planning process. It’s a matter of the EPA providing
better guidance and the states’ being willing to bite
the bullet and do the work.”
Journalist PENELOPE GRENOBLE O'MALLEY
is a frequent contributor to Forester Communications.
OW
- November/December 2005
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