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Abstract from the 1999 American Fisheries
Society Annual Meeting
Used with
Permission
Integrating Fisheries Principles from
Mountain to Marine
Habitats
August 29 – September 2, 1999
Charlotte, North Carolina
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What’s Natural About Managing
Instream Flow Regimes?
Organizers: Mary C. Freeman, Elise R. Irwin, and Donald J. Orth (8)
Moderator: Mary C. Freeman
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The importance of protecting natural patterns of flow regimes for
sustaining the structure and function of river ecosystems has received
renewed interest and publicity over the past few years. Ecologists from
academia, to The Nature Conservancy, to federal agencies including the
Army Corps of Engineers have presented arguments for protecting natural
patterns of spatial and temporal variability in managed river systems.
We have witnessed the unprecedented experimental release of flood waters
in the Southwest, calls for reevaluation of flood-control policy in the
East and Midwest, and the initiation of multibillion-dollar projects to
restore natural form and flows to the aquatic systems of south Florida.
Managers have access to new methodologies (e.g., Indicators of
Hydrologic Alteration, the Riverine Community Habitat Assessment and
Restoration Concept) for assessing how far managed regimes depart from
natural patterns. These methodologies are intended to augment or replace
criteria-based approaches (principally IFIM) widely used by fisheries
managers to negotiate for fish-friendly flows in regulated streams.
However, resource managers may partly view the natural flow approach as
an appealing ecological theory that lacks extensive empirical backing
– how natural is close enough? Further, how may other emerging
approaches, including individual-based and basin-management models,
complement or diverge from strategies to protect natural flow
variability? This symposium will delve the theoretical and empirical
bases for justifying instream flows to protect fishes and fisheries as
well as stream ecosystems. By bringing together ecologists and fisheries
scientists (in the same corpus, in some cases), we will facilitate
discussion of the evolving roles of natural flow regimes and habitat
models in improving the management of flow-regulated streams.
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Symposia Sessions
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Natural Flow
Variability and Riverine Management
N. LeRoy Poff (Department of Biology, Colorado State University,
Fort Collins, CO 80523-1858; 970/491-2079; FAX 970/491-0649; poff@lamar.colostate.edu)
Streams and rivers are naturally dynamic and
variable, both in their physical character and their ecological
relationships. The seasonality of high and low flows and the
natural swings between wet and dry years create and maintain a
diversity of habitat types (both in and outside the channel)
that benefit a wide range of species, including fish. Human
management of streams and rivers typically alters natural
patterns of flow variability, resulting in new environmental
conditions, which are often unfavorable to native aquatic and
riparian species and to long-term ecosystem integrity.
Accumulated ecological knowledge illustrates that a narrow focus
on minimum flow as the basis for riverine management is
inadequate. Yet, the implementation of more natural flow regimes
may face practical obstacles because managers struggle with
answering the questions of "how much flow" and
"how much variability" are needed (and can be
justified) for any particular river system. Arriving at
site-specific, "natural" flow recommendations requires
an expansion of the management framework from one based largely
on habitat to one based on critical ecological processes that
can be explicitly linked to natural flow variability.
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(Symposia Sessions)
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Defining
Flow Regime Criteria for Southeastern Rivers
Elise R. Irwin*(USGS, Alabama Cooperative Fish and
Wildlife Research Unit, 119 Swingle Hall, Auburn University,
Alabama 36849; 334/844-9190; FAX 334/844-9208; eirwin@acesag.auburn.edu)
Mary C. Freeman (USGS Patuxent Wildlife Research Center,
Warnell School of Forest Resources, University of Georgia,
Athens, Georgia 30602-2152; 706/542-5181; FAX 706/542-1235; mary_freeman@usgs.gov)
Byron J. Freeman (Institute of Ecology, University of
Georgia, Athens, GA 30602; 706/542-2968; FAX 706/542-4060; bud@ttrout.ecology.uga.edu)
J. Jeffery Isely (USGS, South Carolina Cooperative Fish and
Wildlife Research Unit, Clemson, South Carolina, 29634;
864/656-1265; jisely@clemson.edu)
Definition of flow regimes to protect fish communities and
provide productive fisheries should involve collection of data
over time to encompass variability in hydrologic regimes and
fish population parameters. More often, instream flow
negotiations are based on a necessarily incomplete understanding
of mechanisms linking fish populations to hydrologic regimes,
and then the resulting effects go unmonitored. Empirical
relations between biological and hydrological parameters are
being studied in several southeastern rivers with the potential
to support adaptive flow management. Responses of fish
assemblages to variously depleted and restored base flows and to
short-term flow instability are providing insight to mechanisms
of population persistence in altered flow regimes.
Species-specific efforts include addressing depressed
young-of-year recruitment by Micropterus and Moxostoma
species in hydropeaking regimes. Based on these longer-term
studies, we identify biologically-critical aspects of the flow
regime, including: incidence of prolonged, high spring flows,
stable low flows during summer, and mitigation of low
temperatures during hydropower production. We recommend using
available biological data in conjunction with hydrologic data to
develop adaptive management regimes for regulated southeastern
rivers.
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(Symposia Sessions)
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Lots of Data
and No Data: Strategies for Negotiating Instream Flow Agreements
with Varying Amounts of Information
Gary E. Whelan (Michigan Department of Natural
Resources, Fisheries Division, P.O. Box 30446, Lansing, MI
48909; 517/373-6948; whelang@state.mi.us)
Currently, there are many opportunities to protect instream
flows using a wide range of administrative processes, such as
water right adjudication hearings and the licensing of
hydroelectric projects regulated by the Federal Energy
Regulatory Commission (FERC). A particularly successful strategy
to get the necessary flows to rehabilitate stream ecosystems is
to develop binding settlement agreements. A wide range of data
availability confronts the resource professional when they try
to negotiate such agreements, from piles of Instream Flow
Incremental Methodology (IFIM) data coupled with flow routing
modeling results to a very limited amount of information,
perhaps just hydrological data. It is possible to complete
settlements under both conditions. This talk will use two case
histories, the Consumers Power Company Settlement Agreement on
AuSable, Manistee and Muskegon Rivers (CPCo Settlement) and the
Wilderness Shores Settlement Agreement on the Menominee River
system (WSSA), to show how large and small amounts of data were
used to successfully obtain settlements.
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(Symposia Sessions)
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Beyond
Minimum Flows: Assessing Interstate Water Allocation
Proposals in the Southeastern U.S.
Jerry W. Ziewitz (USFWS, Ecological Services Field
Office, 1612 June Avenue, Panama City, Florida 32405-3721;
850/769-0052; FAX 850/763-2177; Jerry_Ziewitz@fws.gov)
Mary C. Freeman (USGS, Patuxent Wildlife Research Center,
University of Georgia, Athens, Georgia 30602-2152; 706/542-5181;
FAX 706/543-1235; Mary_Freeman@usgs.gov)
The states of Alabama,
Georgia, and Florida are negotiating water allocation formulas
under the Apalachicola-Chattahoochee-Flint and Alabama-Coosa-Tallapoosa
River Basin Interstate Compacts, created by federal legislation
in 1997. Many reaches of these two large interstate basins are
highly altered by dams, pollution, and exotic species; however,
both basins rank high nationally in aquatic species richness and
many reaches retain much of their native biodiversity. The
future of this biodiversity may largely depend on how the states
affect flow regimes through their water allocation decisions.
Using the results of hydrologic models developed by the states,
we compare simulated river flow under the states' various
allocation proposals to observed flow records and to a
synthesized unimpaired flow data set. We interpret the
biological significance of these comparisons using available
data to relate flow regime alterations with effects on riverine
biota. In particular, we present evidence for the biological
significance of frequency, duration, and timing of low- and
high-flow pulses, regime features not usually addressed in
instream flow investigations or policies. We recommend that the
state negotiators adopt allocation formulas that protect water
quality and minimize alterations to natural flow regimes through
limits on water consumption and controls on reservoir
operations.
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(Symposia Sessions)
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What
can we do when the natural flow paradigm is unworkable? A
watershed approach to ecosystem management
Larry L. Olmsted, Duke Power
Standards for flow management
provide only rough guidance because they are inevitably based on
limited field research and the assumption that some arbitrary
deviation from average conditions is undesirable. The natural
flow paradigm is the latest example of a standard setting
approach to flow management. The natural flow paradigm is
unworkable in many rivers, which are highly altered by land
settlement, dams, and lakeside communities. What's a power
company to do? Duke Energy has supported the development of an
integrated ecosystem management framework for the Catawba River
drainage of North and South Carolina. Here, the natural flow
paradigm may not effectively restore historical functions,
especially where native vegetation and riparian gallery forests
have been replaced by intense agricultural and forest
production, suburban and urban development, and extensive
improved highway networks. The WARMF (Watershed Analysis and
Risk Management Framework) links land and water models to
address management issues in a scientific manner. The system can
be used to address complex tradeoffs that will be necessary in
upcoming FERC licensing procedures.
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(Symposia Sessions)
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