The Science of Instream Flows A Review of the Texas Instream Flow Program (2005) / Chapter Skim
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4 Evaluation of the Texas Instream Flow Programmatic Work Plan
4 Evaluation of the Texas Instream Flow Programmatic Work Plan
Pages 58-74
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From page 58... ...
The Texas instream flow program is described in the PWP and its companion document, Texas Instream Flow Studies: Technical Overview (TOD; TPWD, TCEQ, and TWDB, 2003)
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From page 59... ...
, Brazos River (lower subbasin) , San Antonio River (lower subbasin)
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From page 60... ...
Chapter 3 of this report identifies seven principles of state-of-thescience instream flow programs: Preserve whole functioning ecosystems Mimic, to the extent possible, a natural flow regime
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From page 61... ...
. Include the riparian corridor and floodplain in the spatial scope of the study Conduct studies using an interdisciplinary approach Use a variety of tools and approaches appropriate for particular rivers Practice adaptive management.
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From page 62... ...
Other aspects of the PWP that need revision or clarification are the PWP flowchart, use of existing and reconnaissance data in the detailed technical evaluations, scaling issues, monitoring and validation, adaptive management, and stakeholder involvement. State-wide Comparability with Studies Tailored to Local Conditions Texas Senate Bill 2 directed the agencies to develop and maintain "an instream flow data collection and evaluation program" and the PWP generally refers to the instream flow effort as a program.
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From page 63... ...
Finally, there is significant biological diversity across the state. All of these factors support a second level of oversight in the Texas instream flow program that promotes studies that are designed based on the specific characteristics of the study subbasin.
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From page 64... ...
These three actions will provide the needed information and data structure to compare methods and results from different subbasin studies; integrate findings, as appropriate, from different subbasins; and share important instream flow study information across the life of the instream flow program and all of the state, academic and private sector personnel who will be involved in the program. Programmatic and Basin-Specific Goals Establishing unambiguous management goals and objectives is an important component, perhaps the most important component, of any viable instream flow program (see Goals section, Chapter 3)
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From page 65... ...
One state-wide goal is stated in the Senate Bill 2 language: to conduct studies to support a "sound ecological environment" in Texas rivers. This is a clearly stated goal; however, neither the Bill nor the PWP defines the phrase "sound ecological environment," which has left its meaning open to interpretation.
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From page 66... ...
For example, the results of the hydrologic, biological, water quality and physical processes evaluations must be interpreted together to develop instream flow recommendations and each of these discipline evaluations is typically made up of a collection of separate studies. Thus, a diagrammatic representation can get quite complicated with multiple inputs and feedback loops (see for example Bovee, 1998)
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From page 67... ...
and used to design the detailed technical evaluations (second step) ; specify spatial scales during the study design of the technical evaluations; clarify the process for integrating information; consider implementation issues; and include more information about the use of indicators and monitoring.
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From page 68... ...
68 The Science of Instream Flows: A Review of the Texas Instream Flow Program Set Goals Study Design Analyze existing information and conduct reconnaissance studies Develop conceptual model of system Refine goals if necessary Determine geographic scope Develop interdisciplinary study plan specific for the basin Detailed Technical Evaluations Hydrology and Hydraulics Water Quality Biology Physical Processes Integrate Technical Studies and Develop Instream Flow Recommendations Study Report Implementation Monitoring, Evaluation, and Adaptive Management FIGURE 4-2 Recommended flowchart for instream flow studies.
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From page 69... ...
The PWP and the TOD need better explanation of the process whereby existing information and reconnaissance studies will be used to guide the detailed technical evaluations of hydrology, physical processes, biology, and water quality. Designing the technical evaluations from existing and reconnaissance data is an involved, but important step in the instream flow process.
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From page 70... ...
The PWP and the TOD will be strengthened by addressing the issues of scale and comparability of studies conducted within the different disciplines. Ensuring that the different technical evaluations are conducted at commensurate spatial and temporal scales appropriate to derive an instream flow recommendation is the key scaling issue for the Texas instream flow program.
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From page 71... ...
First, if monitoring results suggest that the instream flow goals are not being met, it could provoke water managers and scientists to modify the instream flow recommendations. Second, if ecosystem benefits associated with implementation of instream flows can be documented, that documentation will help build societal and scientific support for the instream flow program.
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From page 72... ...
. An adaptive management approach is encouraged to be used in the Texas instream flow program to account for mid-course corrections and respond to long-term monitoring results.
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From page 73... ...
SUMMARY AND RECOMMENDATIONS The PWP is a relatively brief document that describes the programmatic aspects of the Texas instream flow program. It lays out agency roles and responsibilities, its legislative mandate, priority instream flow studies in Texas, the scope of instream flow studies, and instream flow study elements.
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From page 74... ...
5) The PWP and the TOD should describe how existing information and reconnaissance studies will be used to guide the detailed technical evaluations of hydrology, physical processes, biology, and water quality.
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