THE EDWARDS AQUIFER and its Unique Ecosystem potential

THE EDWARDS AQUIFER and its Unique Ecosystem – potential threats from Groundwater Management Glenn Longley Director Edwards Aquifer Research & Data Center 1

Outline S Hydrologic Setting of Edwards (BFZ) Aquifer S Unique Aquatic Ecosystem S History of Management S Current work S Summary S Contact information P 2

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Edwards Aquifer San Antonio portion of FZ • Elevation near 575 feet ↘ SM spgs Comal spgs Elevation near 1400 feet ↘ SA spgs Leona spgs Watershed Recharge Zone Artesian Zone P 4

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San Marcos Springs P 10

Barton Springs Segment (BFZ) Aquifer P 11

Unique? How? S 40+ species of Invertebrates S 4+ species of Vertebrates P 12

Discoveries made in the last 20 years S Diversity of Amphipods, snails & overall S Presence of marine relicts S Monodella S Some amphipod families S Foraminiferans S New species, deep aquifer system S More detailed information about vertebrates P 13

Community diversity S Greatest in Amphipods (12 species-5 families) S Other Arthropods (13 species representing 8 families) S Next is Mollusca (10 species of Hydrobiid snail family) P 14

More about diversity S Biological diversity is important Ecological stability S The species in this system may hold important genetic information P 15

Marine relicts S Amphipods in the families: Hadziidae, Bogidiellidae, & Sebidae S These families are primarily marine with few examples of freshwater sp. S Hadziids are distributed today around the Caribbean and Mediterranean S These areas are important as remnants of the Tethys Sea P 16

Marine relicts S May assist in better understanding of how the aquifer formed and its relationship with paleomarine areas S Additional studies of these species will shed light on paleogeography P 17

Other marine relicts in the Aquifer S Monodella texana (Only N. A. Thermosbaenacean) S M. texana’s marine ancestors are represented by groups in the W. Indies S A Foraminiferan from the Lagenidae (Probably Robulus sp) was found P 18

Other marine relicts continued S Foraminiferans have only been found in fresh water from wells (Trans Caspian Province) S Cirolanid isopods (predominantly marine) are also found P 19

New species S 8 new snails, 2 others renamed S 10 new amphipods, 1 new family (Artesiidae) S 1 new aquatic beetle - Hadeoporus texanus (larvae & adult described) S 1 new vertebrate described - Typhlomolge robusta P 20

Flowing Edwards well with biomass being discharged southwest of San Antonio, Texas P 21

Texas State University Artesian Well S Drilled in 1895 to furnish water for Federal Fish Hatchery S Five foot cavern at 195 feet S Source of water is Edwards Aquifer S Sampled continuously since early 70’s P 22

64 micron mesh net on 12” discharge with removable sample chamber P 23

Two day sample out of Texas State Artesian well net P 24

Filamentous colonies of fungi and other organisms P 25

Placing a net on flowing well at San Antonio Zoo P 26

Invertebrate Fauna S TURBELLARIA: (Flatworms) S Kenkiidae S Sphalloplana mohri Hyman S NEMATODA: (Roundworms) S Rhabdochonidae S Rhabdochona longleyi Moravec & Huffman P 27

Sphalloplana mohri P 28

Gastropods (Snails) S Hydrobiidae S Phreatodrobia conica Hershler & Longley Hueco cavesnail S P. coronae Hershler & Longley S P. imitata Hershler & Longley mimic cavesnail S P. micra (Pilsbry & Ferris) flattened cavesnail S P. nugax inclinata Hershler & Longley S P. nugax (Pilsbry & Ferris) domed cavesnail S P. plana Hershler & Longley disc cavesnail S P. punctata Hershler & Longley high-hat cavesnail S P. rotunda Hershler & Longley beaked cavesnail S Phreatoceras taylori Hershler & Longley nymph trumpet S Balconorbis uvaldensis Hershler & Longley Balcones ghostsnail S Stygopyrgus bartonensis Hershler & Longley Barton cavesnail S Texapyrgus longleyi Thompson & Hershler striated hydrobe P 29

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HIRUDINEA (Leeches) Erpobdellidae: S Mooreobdella microstoma Pawlowski P 31

Crustaceans S OSTRACODA: Entocytheridae S Sphaeromicola (Hobbsiella) moria Hart S ISOPODA: S S S Cirolanidae Caecidotea reddelli (Steeves) Cirolanides texensis Benedict Asellidae Lirceolus pilus (Steeves) L. smithi (Ulrich) Texas troglobitic Water Slater S Mexistenasellus sp. P 32

Asellid Isopod P 33

Mexistenasellus sp. P 34

AMPHIPODS S Hadziidae S Allotexiweckelia hirsuta Holsinger S Holsingerius samacos (Holsinger) S Texiweckelia texensis (Holsinger) S Texiweckeliopsis insolita (Holsinger) P 35

Amphipods continued S Stygobromus balconis (Hubricht) S Crangonyctidae S S. bifurcatus (Holsinger) S S. flagellatus (Benedict) S S. pecki (Holsinger) S S. russelli (Holsinger) S Sebidae S Seborgia relicta Holsinger S Bogidiellidae S Artesia subterranea Holsinger S Parabogidiella americana Holsinger P 36

Stygobromus sp. P 37

CRUSTACEANS continued S THERMOSBAENACEA: S Monodellidae S Monodella texana Maguire S DECAPODA: S Palaemonidae S Palaemonetes antrorum Benedict S P. holthuisi Strength P 38

Monodella texana P 39

Paleomonetes antrorum P 40

COLEOPTERA: (Insect – beetles) S Dryopidae S Stygoparnus comalensis Barr & Spangler S Dytiscidae S Comaldessus stygius Spangler & Barr S Haideoporus texanus Young & Longley Edwards Aquifer water beetle P 41

Haideoporus texanus P 42

VERTEBRATES PISCES: (Fish) S Ictaluridae S Satan eurystomus Hubbs & Bailey Widemouth blindcat S Trogloglanis pattersoni Eigenmann Toothless blindcat P 43

Satan eurystomus P 44

Trogloglanis pattersoni S Toothless blindcat S Found in same area of Widemouth Blindcat S Shallowest collection 1350’ below surface S Deepest 2000’ S Only below San Antonio TX area P 45

CAUDATA: Tailed amphibians S Plethodontidae S Eurycea chisholmensis Chippindale, Price & Hillis Salado salamander S E. latitans Smith & Potter S Cascade Caverns salamander S E. naufragia Chippindale, Price & Hillis S E. sp. nov. Comal S E. nana Bishop S San Marcos salamander S E. neotenes Bishop & Wright S Texas salamander S E. pterophila Burger, Smith & Potter S Fernbank salamander S E. rathbuni (Stejneger) S Texas Blind salamander S S S E. robusta (Longley) Blanco Blind salamander E. sosorum Chippindale, Price & Hillis Barton Springs salamander E. tonkawae Chippindale, Price & Hillis. Jollyville salamander E. tridentifera Mitchell & Reddell Comal blind salamander E. troglodytes Baker Valdina Farms salamander E. sp. Comal Springs salamander P 46

Eurycea rathbuni Texas Blind Salamander P 47

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PSan Antonio portion of the Balcones Fault Zone Edwards Aquifer P 49

Bexar Co. Texas “Catfish Well” flows at > 30 MGD P 50

History of Management S 1983 - EUWD given authority to regulate transport of water out of district (5 counties) S 1987 – EUWD gains legislative approval for a drought management plan (DMP) S 1988 -90 – DMP requirements set S 1989 – Two western Counties withdraw from District S May 1991 – SA defeats construction of Applewhite Reservoir (Alternate source) S May 1991 – Sierra Club files suit against USFWS P 51

History Continued S Sierra Club suit asks that USFWS be required to insure min. springflow to protect endangered species. S EUWD and SARA file suit against Living Waters (Catfish Well owners) for waste and water quality issues. S 1992 – TWC declares Edwards Aquifer to be an underground river, therefore regulated by the state S Later that year State Court invalidates TWCs determination P 52

History continued S Nov 16, 1992 Trial begins in U. S. District Court for Sierra Club lawsuit. S Jan 30, 1993 – U. S. Dist. Judge Bunton rule for the Sierra Club and orders: µSpringflow must be maintained µTWC must submit plan to court by March 1993 to assure Comal & San Marcos Springs do not drop below Jeopardy levels µUSFWS must develop springflow thresholds for take & jeopardy µTx Legislature must develop regulations to limit withdrawals by May 31, 1993. P 53

History continued S May 30, 1993 – Texas Legislature adopts SB 1477 that creates the Edwards Aquifer Authority (EAA) with a 9 member appointed board S Aug. 30, 1993 – U. S. Justice Dept. ruled legislation may have violated the Voting Rights Act, in November they determined it did S Feb. 1994 – Fed. Court Appointed monitor to gather information for the court. P 54

Hydrologic S Less storage in aquifer (1 ft of head = approx. 35, 000 acre feet). S Low flows of San Marcos Springs occur sooner during critical dry periods. S Greater potential for saline water intrusion during critical periods. P 55

Ecological SLower flows would possibly jeopardize listed species sooner. P 56

Threats to the system S Historic lows vs. recent time (recharge & discharge) S Increasing water use S Aquifer Storage & recovery S Proposed policy to raise pumping caps S Proposed policy to limit minimal pumping required during drought P 57

Summary 58

Detailed studies (Past & Continuing) S Texas Blind Salamander - Typhlomolge rathbuni S Two blindcatfish from San Antonio area: Satan eurystomus & Trogloglanis pattersoni (Ictaluridae) S Distribution of species throughout the aquifer, important in showing hydrologic relationships P 59

Studies currently underway S Water Quality - investigating freshwater/saline water interface S Modeling of groundwater hydrology and the effect of pumping P 60

This system is a microcosm of problems in our world S Population growth and human demands threaten the system and the surface ecosystems (springs) it supports S We should educate the users of water from the aquifer about its dynamics S Its importance as the habitat for a community of organisms P 61

Additional studies needed S Biomagnification of contaminants up the aquifer food chain S Toxicity studies of specific members of the aquifer community S Additional studies of rarer species S Energy flow and sources in the deep confined aquifer P 62

Acknowledgements S The work on the aquifer through the years has been supported by USFWS, TPWD, USDA, USEPA and numerous other sources too numerous to mention. S Staff of the Research Center, Graduate Students, Collaborators and numerous others have assisted in developing the information about the Aquifer community. S Texas State University has been very supportive of this work. P 63

Thank you! S I can be reached at the following: S email: GL 01@txstate. edu S EARDC homepage: http: //www. eardc. txstate. edu S Phone: 512 -245 -3581 S Fax: 512 -245 -2669 S Feel free to contact me with questions. P 64