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Pages 1-10

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From page 1...
... , the Texas blind salamander, the Comal Springs dryopid beetle, the Comal Springs riffle beetle, Peck's cave amphipod, Texas wild rice, and the San Marcos salamander. To protect the listed species, the Edwards Aquifer Authority (EAA)
From page 2...
... It tackles the issues of how to represent recharge and conduits in the modeling and how to conduct uncertainty analysis. Chapter 3 describes the state of ecological modeling for Comal and San Marcos Springs, focusing on the fountain darter, submersed aquatic vegetation, Texas wild rice, and the Comal Springs riffle beetle.
From page 3...
... The hydrologic modeling activities that are the subject of the Chapter 2 review include updates to the MODFLOW model, creation of a new finite element model of the aquifer, better aquifer characterization and delineation of boundary conditions, development of new methods for determining recharge, and uncertainty analysis. The hydrologic modeling effort has shown continuous improvement in both the use of models and the incorporation of new data.
From page 4...
... Three of the endangered species -- the fountain darter, the Comal Springs riffle beetle, and Texas wild rice -- have been designated as indicator species within the HCP and, along with submersed aquatic vegetation, are the initial targets of modeling efforts, including both habitat suitability analyses and predictive ecological models. In general, the approach to ecological modeling of combining field data, habitat suitability analyses, and a population dynamics model is appropriate and can support the management decisions that will need to be made as the HCP proceeds.
From page 5...
... It is recommended that as a top priority the EAA develop an ecosystembased conceptual model, or a series of models of increasing resolution, that show how water quality and quantity, other biota, and restoration and mitigation activities are expected to interact with the indicator species, as well as with all covered species. Boxes in the conceptual model would represent targets of the monitoring program, while arrows linking the boxes would represent quantitative or empirically derived relationships between the boxes based on research.
From page 6...
... . At the same time, a large-scale stratified random survey of the potential habitat available in both systems would provide more robust data on how flow variation and sedimentation affect the habitat and thus population numbers of the Comal Springs riffle beetle.
From page 7...
... At the present time, there is considerably more knowledge about fountain darters and Texas wild rice than about the Comal Springs riffle beetle and most of the other ESA-listed species. The Applied Research Program is intended to fill knowledge gaps about the endangered species in the Comal and San Marcos systems, particularly under low flow conditions, and to provide data and information that can be used to parameterize and validate the ecological models.
From page 8...
... Beyond considering new research topics, the Applied Research Program could be restructured to help to ensure that the limited funds available for the program target priority research needs to support the ecological modeling efforts and the success of the HCP more generally. The following structural modifications to further increase the usefulness and efficiency of the current program are recommended.
From page 9...
... As mentioned previously, an overall conceptual model of the system including hydrological, climate, and biological community components could guide the development of quantitative modeling of sub-components, identify gaps in understanding, and provide context for understanding the responses of particular species of interest. A second way to achieve integration would be to develop a comprehensive data/information management system.
From page 10...
... Examples of potential future "worst case" scenarios worth considering are: • increased groundwater pumping from exempt/unregulated wells that undermines the HCP's minimum flow requirements; • drought conditions that exceed the drought of record from the 1950s; • climate change impacts become significant faster than expected; • high court affirmation of the Bragg constitutional takings decision; and • subjugation to Aransas National Wildlife Refuge ESA issues. These scenarios and others, along with their implications to the HCP, are described in detail in Chapter 6.


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