Time Allowance: 30 minutes
1.2.1 Define "Sound Ecological
Environment"
Senate Bill 2 (Instream Flows Program)
Fluvial
A resilient, functioning ecosystem characterized by intact, natural processes and a balanced, integrated, and
adaptive community of organisms comparable to that of the natural habitat of a region.
(Texas Instream Flow Program, Technical Overview, Page 11)
Texas Bays & Estuary Program
Estuarine
Conceptual
An estuary can be considered to be ecologically sound when the typical physical, chemical, and biological
parameters that are measured--including the characteristic biological communities--fall within the range of
values that historically occurred before humans interfered with natural processes (e.g. by constructing
waterways, introducing pollutants, and altering freshwater inflows).
Note: how can this possibly be feasible for the Sabine-Neches Estuary? See Operational, below.
Longley, W.L. ed. 1994. Freshwater inflows to Texas bays and estuaries: ecological relationships and methods
for determination of needs. Texas Water Development Board and Texas Parks and Wildlife Department,
Austin, TX. 386 pp.
Operational
An ecologically sound estuarine environment can be defined as one having densities of animals and plants not
significantly different from the historical patterns of abundance or composition.
In practice, this can be difficult unless the physical and chemical properties are sufficiently close to historical
conditions so that the biotic communities are not degraded. (Longley, 1994).
Time Allowance: 30 minutes
EFAC and SAC
A sound ecological environment is one that:
 sustains the full complement of native species in perpetuity,
 sustains key habitat features required by these species,
 retains key features of the natural flow regime required by these species to complete their life cycles,
and
 sustains key ecosystem processes and services, such as elemental cycling and the productivity of
important plant and animal populations.
This can be found on page 15 of Environmental Flows Advisory Committee, Final Report, December 2006:
http://www.tceq.state.tx.us/assets/public/permitting/watersupply/water_rights/txefsac8132008article5.pdf
It is also included in the SAC Guidance Methodologies for Establishing a Freshwater Inflow Regime for Texas
Estuaries Within the Context of the Senate Bill 3 Environmental Flows Process, with the addition that:
Underlying each of these is the need to establish relationships between elements of the environment, including
flows, and the native species and their functions.
ISF Conference (Dr. Winemiller)
Slide set
See document: winemiller_flows-conf-05-5 - 1 per.pdf
Seeking a Sound Ecological Environment: Biotic Responses to Instream Flow Variation. Dr. Kirk Winemiller
Flows for the Future. 2005 Environmental Flow Conference.
http://www.rivers.txstate.edu/flows2005/
Challenge
Make the concept of a "sound ecological environment" operational.
What is the definition of “operational” in this context?
Definition
A sound ecological environment:
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

sustains the full complement of native species in perpetuity
sustains key habitat features required by species
retains key features of the natural flow regime required by species to complete their life cycles
sustains key ecosystem processes & services, such as elemental cycling & productivity of important
plant & animal populations
Time Allowance: 30 minutes
Questions to Answer In Order to Define a Sound Ecological Environment
Communication from Roger Kelley
A sound ecological environment is one that:




sustains the full complement of native species in perpetuity,
sustains key habitat features required by these species,
retains key features of the natural flow regime required by these species to complete
their life cycles, and
sustains key ecosystem processes and services, such as elemental cycling and the
productivity of important plant and animal populations.
1. How long has the riverine system been at the current ecological state?
2. What defines a balanced, integrated and adaptive community or organisms?
3. How dynamic is the system at status quo with no change in the natural environment?
4. What are the probabilities that the natural habitat will remain static, i.e. can we control
nature?
5. How statistically relevant is the current data; is it possible or even desirable to “freeze”
the ecological conditions/habitat and develop a flow regime that will accomplish this
goal?
6. What are we trying to protect?
7. Are we to or can we “freeze” the current ecological system and not allow it to change
with time under natural conditions? And what about other influences, e.g. hurricanes,
floods, ship channel dredging, etc.
Time Allowance: 30 minutes
Other?
Adopted