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1 Introduction
Pages 11-40

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From page 11...
... as endangered species: the fountain darter, the San Marcos gambusia (presumed extinct) , the Texas blind salamander, the Comal Springs dryopid beetle, the Comal Springs riffle beetle, Peck's Cave amphipod, and Texas wild rice.
From page 12...
... During this drought, flows at Comal Springs ceased for 4 months and flows at San Marcos Springs were severely reduced. At current pumping levels, a similar drought today could result in complete cessation of flow at Comal Springs for more than 3 years and near cessation of flow at San Marcos Springs (EARIP, 2012)
From page 13...
... and four other local entities applied for an Incidental Take Permit under the ESA, creating a 15-year Habitat Conservation Plan as part of the application process. The EAA is a regional government body tasked with managing domestic, industrial, and agricultural withdrawals from the Edwards Aquifer while maintaining spring flows at quantities that can support recreation and ESA-listed species.
From page 14...
... Comal and San Marcos Springs are located within the San Antonio segment of the Edwards Aquifer, which spans approximately 3,600 square miles and is the focus of the Habitat Conservation Plan and this report. One important boundary in the Edwards Aquifer system is the southern boundary, which is defined by the freshwater/saltwater transition zone
From page 15...
... concentration line. Saltwater intrusion into the artesian zone is one of the risks that pumping of the Edwards Aquifer poses to the system.
From page 16...
... in the limestones. This triple-permeability nature of the Edwards Aquifer -- matrix, karst, and fracture flow -- contributes to vast local differences in groundwater flow regimes.
From page 17...
... The mean annual precipitation for San Antonio from 1934 through 2013 is approximately 30.38 inches, although annual precipitation may vary from year to year by more than 20 inches. Figure 1-5 demonstrates this variability for the San Antonio area.
From page 18...
... This period is recognized as the "drought of record" and coincides with a 144-day cessation of flow at Comal Springs in 1956 (Longley, 1995)
From page 19...
... indicate that the remaining 20 to 40 percent of the recharge occurs as direct infiltration within the recharge zone, as well as leakage from the underlying Trinity Aquifer. Leakage from lateral aquifer segments into the San Antonio segment of the Edwards Aquifer and also from adjacent aquifers occurs where hydrologic connections exist, such as along fault zones and through low-confinement border conditions.
From page 20...
... Total discharge ranged from a low of 388,800 acre-feet in 1955 to a high of 1,130,000 acre-feet in 1992, with FIGURE 1-6  Estimated Annual Recharge and 10-Year Floating Median Estimated Recharge for San Antonio Segment of the Edwards Aquifer, 1934–2012. SOURCE: Figure 8 from EAA (2013)
From page 21...
... These species include a variety of submersed aquatic vegetation (SAV) like Texas wild rice; several fish, including the fountain darter; amphibians such as the Texas blind salamander; birds like the whooping crane; and a variety of invertebrates.
From page 22...
... . Invasive species of concern include the Asian trematode Centrocestus formosanus, a parasite that attaches to fish's gill filaments, including fountain darters; the giant ramshorn snail, which grazes on aquatic plants and could negatively impact fountain darter habitat during low flow conditions; non-native fish such as tilapia and suckermouth catfish; and TABLE 1-1 Common and Scientific Names of Species Proposed for Coverage under the Edwards Aquifer Habitat Conservation Plan and Their Status According to the Endangered Species Act Common Name Scientific Name ESA Status Fountain Darter Etheostoma fonticola Endangered Comal Springs Riffle Beetle Heterelmis comalensis Endangered San Marcos Gambusia Gambusia georgei Endangered Comal Springs Dryopid Beetle Stygoparnus comalensis Endangered Peck's Cave Amphipod Stygobromus pecki Endangered Texas Wild Rice Zizania texana Endangered Texas Blind Salamander Eurycea rathbuni Endangered San Marcos Salamander Eurycea nana Threatened Edwards Aquifer Diving Beetle Haideoporus texanus Petitioned*
From page 23...
... . With regard to endangered species of plants, like Texas wild rice, Section 9 makes it illegal to "remove and reduce to possession any such species from areas under Federal jurisdiction; maliciously damage or destroy any such species on any such area; or remove, cut, dig up, or damage or destroy any such species on any other area in knowing violation of any law or regulation of any State or in the course of any violation of a State criminal trespass law" (16 U.S.C.
From page 24...
... THE EDWARDS AQUIFER AUTHORITY AND THE HABITAT CONSERVATION PLAN The Edwards Aquifer ESA-listed species have been the subject of litigation since at least 1991. For example, one lawsuit, Sierra Club v.
From page 25...
... The Incidental Take Permit and Habitat Conservation Plan Despite litigation over the groundwater permitting program, the EAA and several other entities pursued an ESA Section 10 ITP to limit their
From page 26...
... , an initiative that came to be known as the Edwards Aquifer Recovery Implementation Program. In 2007, the Texas Legislature directed the EAA, the City of San Antonio acting through the San Antonio Water System, the City of San Marcos, the City of New Braunfels, and Texas State University to participate in the Edwards Aquifer Recovery Implementation Program and to develop a plan for managing the Edwards Aquifer in a manner that would protect and conserve the federally listed species in the event of conditions similar to the drought of record.
From page 27...
... Comal Springs Dryopid Beetle 1,543 Comal Springs Riffle Beetle 11,179 Peck's Cave Amphipod 18,224 Texas Wild Rice Plant; different standards. Texas Blind Salamander 10 San Marcos Salamander 263,857 Texas Cave Diving Beetle Judged by minimum flow requirements Comal Springs Salamander Judged by minimum flow requirements Texas Troglobitic Water Slater Judged by minimum flow requirements Species Covered by the HCP The HCP applies to 11 Edwards Aquifer species -- the eight already listed under the federal ESA and three others that have been proposed for listing (Table 1-1)
From page 28...
... 18, 1997 U.S. FWS lists the Comal Springs riffle beetle, the Comal Springs dryopid beetle, and the Peck's Cave amphipod as endangered species under the ESA.
From page 29...
... The Role of Indicator Species under the HCP Rather than attempting to devise an HCP that would address all 11 covered species individually, the HCP identifies three indicator species -- the fountain darter, the Comal Springs riffle beetle, and Texas wild rice -- to represent all covered species. The HCP assumes that all of its habitat minimization and mitigation measures for these three species will be sufficient to protect all covered species (EARIP, 2012)
From page 30...
... . First documented and described in 1886 by Jordan and Gilbert, fountain darters are found only in the San Marcos and Comal Springs and their effluent rivers (Guadalupe River system)
From page 31...
... . In 2007, the FWS designated 19.8 acres of the Comal Springs complex and 10.5 acres of the San Marcos Springs complex as critical habitat for Comal Springs riffle beetles, dryopid beetles, and Peck's Cave amphipod (USFWS, 2007)
From page 32...
... is a smooth, unpigmented subterranean species found only in San Marcos Springs (Longley, 1978)
From page 33...
... The project includes 142 miles of pipeline to provide San Antonio up to 50,000 acre-feet/year of groundwater pumped from the Carrizo Aquifer in Burleson County. Second, beyond spring flow protection measures there are a variety of minimization and mitigation measures designed to maintain and restore the habitat of ESA-listed species at both Comal and San Marcos Springs (see Box 1-1)
From page 34...
... M&M measures specific to San Marcos Springs   5. Texas wild rice enhancement and restoration (5.3.1 and 5.4.1)
From page 35...
... 24. Riparian improvements and sediment removal specific to the Comal Springs riffle beetle (5.2.8)
From page 36...
... , and Comal Springs riffle beetle. These efforts are meant to build upon the HCP's habitat suitability analyses, which led to the current minimum recommended spring flows at Comal and San Marcos Springs to maintain viable populations of the ESA-listed species.
From page 37...
... As Box 1-2 indicates, this report focuses on improving modeling efforts for the Edwards Aquifer. Subsequent NRC reports will review the performance of minimization and mitigation measures, including the four spring flow protection measures, as well as the adequacy of the biological goals and objectives to protect the endangered species.
From page 38...
... This and all subsequent chapters reflect consideration of EAA reports through November 2014. Chapter 3 describes the state of ecological modeling for Comal and San Marcos Springs, focusing on the initial modeling efforts for the fountain darter, SAV, Texas wild rice, and the Comal Springs riffle beetle.
From page 39...
... 2010. Evaluation of hydrologic connection between San Marcos Springs and Barton Springs through the Edwards Aquifer.
From page 40...
... 2007. Part 3 Department of the Interior, Fish and Wildlife Service endangered and threatened wildlife and plants; designation of critical habitat for the Peck's cave amphi pod, Comal Springs dryopid beetle, and Comal Springs riffle beetle; final rule.


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