THE EDWARDS AQUIFER and its Unique Ecosystem –

potential threats from Groundwater Management

Glenn LongleyDirector

Edwards Aquifer Research & Data Center

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Outline

Hydrologic Setting of Edwards (BFZ) Aquifer

Unique Aquatic Ecosystem History of Management Current work Summary Contact information

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Edwards AquiferSan Antonio portion of FZ

WatershedWatershed

RechargeRecharge ZoneZone

ArtesianArtesian ZoneZone

SM spgs

Comal spgs

SA spgs

Leona spgs

Elevation near 1400 feet ↘

•Elevation near 575 feet ↘

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San Marcos Springs

11Barton Springs Segment (BFZ) Aquifer

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Unique? How?

40+ species of Invertebrates 4+ species of Vertebrates

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Discoveries made in the last 20 years

Diversity of Amphipods, snails & overall Presence of marine relicts

Monodella Some amphipod families Foraminiferans

New species, deep aquifer system More detailed information about vertebrates

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Community diversity

Greatest in Amphipods (12 species-5 families)

Other Arthropods (13 species representing 8 families)

Next is Mollusca (10 species of Hydrobiid snail family)

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More about diversity

Biological diversity is important - Ecological stability

The species in this system may hold important genetic information

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Marine relicts

Amphipods in the families: Hadziidae, Bogidiellidae, & Sebidae

These families are primarily marine with few examples of freshwater sp.

Hadziids are distributed today around the Caribbean and Mediterranean

These areas are important as remnants of the Tethys Sea

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Marine relicts

May assist in better understanding of how the aquifer formed and its relationship with paleomarine areas

Additional studies of these species will shed light on paleogeography

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Other marine relicts in the Aquifer

Monodella texana (Only N.A. Thermosbaenacean)

M. texana’s marine ancestors are represented by groups in the W. Indies

A Foraminiferan from the Lagenidae (Probably Robulus sp) was found

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Other marine relicts continued

Foraminiferans have only been found in fresh water from wells (Trans Caspian Province)

Cirolanid isopods (predominantly marine) are also found

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New species

8 new snails, 2 others renamed 10 new amphipods, 1 new family (Artesiidae) 1 new aquatic beetle - Hadeoporus texanus (larvae

& adult described) 1 new vertebrate described - Typhlomolge robusta

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

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Texas State University Artesian Well

Drilled in 1895 to furnish water for Federal Fish Hatchery

Five foot cavern at 195 feet

Source of water is Edwards Aquifer

Sampled continuously since early 70’s

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

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Two day sample out of Texas State Artesian well net

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Filamentous colonies of fungi and other organisms

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Placing a net on flowing well at San Antonio Zoo

TURBELLARIA: (Flatworms) Kenkiidae Sphalloplana mohri Hyman NEMATODA: (Roundworms) Rhabdochonidae Rhabdochona longleyi Moravec & Huffman

Invertebrate Fauna

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Sphalloplana mohri

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Gastropods (Snails) Hydrobiidae Phreatodrobia conica Hershler &

Longley Hueco cavesnail

P. coronae Hershler & Longley

P. imitata Hershler & Longley mimic cavesnail

P. micra (Pilsbry & Ferris) flattened cavesnail

P. nugax inclinata Hershler & Longley

P. nugax nugax (Pilsbry & Ferris) domed cavesnail

P. plana Hershler & Longley disc cavesnail

P. punctata Hershler & Longley high-hat cavesnail

P. rotunda Hershler & Longley beaked cavesnail

Phreatoceras taylori Hershler & Longley nymph trumpet

Balconorbis uvaldensis Hershler & Longley Balcones ghostsnail

Stygopyrgus bartonensis Hershler & Longley Barton cavesnail

Texapyrgus longleyi Thompson & Hershler striated hydrobe

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HIRUDINEA(Leeches)

Erpobdellidae: Mooreobdella microstoma Pawlowski

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Crustaceans

OSTRACODA: Entocytheridae

Sphaeromicola (Hobbsiella) moria

Hart

ISOPODA: Cirolanidae Caecidotea reddelli (Steeves) Cirolanides texensis Benedict Asellidae Lirceolus pilus (Steeves) L. smithi (Ulrich) Texas

troglobitic Water Slater Mexistenasellus sp.

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Asellid Isopod

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Mexistenasellus sp.

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AMPHIPODS

Hadziidae Allotexiweckelia hirsuta Holsinger Holsingerius samacos (Holsinger) Texiweckelia texensis (Holsinger) Texiweckeliopsis insolita (Holsinger)

Amphipods continued

Stygobromus balconis (Hubricht)

Crangonyctidae

S. bifurcatus (Holsinger)

S. flagellatus (Benedict)

S. pecki (Holsinger)

S. russelli (Holsinger)

Sebidae

Seborgia relicta Holsinger

Bogidiellidae

Artesia subterranea Holsinger

Parabogidiella americana Holsinger

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CRUSTACEANS continued

THERMOSBAENACEA: Monodellidae Monodella texana Maguire

DECAPODA: Palaemonidae Palaemonetes

antrorum Benedict P. holthuisi Strength

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Monodella texana

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COLEOPTERA:(Insect – beetles)

Dryopidae Stygoparnus comalensis Barr & Spangler Dytiscidae Comaldessus stygius Spangler & Barr Haideoporus texanus Young & Longley

Edwards Aquifer water beetle

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Haideoporus texanus

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VERTEBRATESPISCES: (Fish)

Ictaluridae Satan eurystomus Hubbs & Bailey

Widemouth blindcat Trogloglanis pattersoni Eigenmann

Toothless blindcat

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Satan eurystomus

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Trogloglanis pattersoni

Toothless blindcat Found in same area of

Widemouth Blindcat Shallowest collection

1350’ below surface Deepest 2000’ Only below San

Antonio TX area

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CAUDATA:Tailed amphibians

Plethodontidae Eurycea chisholmensis Chippindale,

Price & Hillis Salado salamander E. latitans Smith & Potter Cascade Caverns salamander E. naufragia Chippindale, Price &

Hillis E. sp.nov. Comal E. nana Bishop San Marcos salamander E. neotenes Bishop & Wright Texas salamander E. pterophila Burger, Smith & Potter Fernbank salamander E. rathbuni (Stejneger) Texas Blind salamander

E. robusta (Longley) Blanco Blind salamander E. sosorum Chippindale, Price & Hillis Barton Springs salamander E. tonkawae Chippindale, Price &

HillisJollyville salamander E. tridentifera Mitchell & Reddell Comal blind salamander E. troglodytes Baker Valdina Farms salamander E. sp. Comal Springs salamander

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Eurycea rathbuni Texas Blind Salamander

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San Antonio portion of the Balcones Fault Zone Edwards Aquifer

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

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History of Management 1983 - EUWD given authority to regulate

transport of water out of district (5 counties) 1987 – EUWD gains legislative approval

for a drought management plan (DMP) 1988-90 – DMP requirements set 1989 – Two western Counties withdraw

from District May 1991 – SA defeats construction of

Applewhite Reservoir (Alternate source) May 1991 – Sierra Club files suit against

USFWS

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History Continued Sierra Club suit asks that USFWS be

required to insure min. springflow to protect endangered species.

EUWD and SARA file suit against Living Waters (Catfish Well owners) for waste and water quality issues.

1992 – TWC declares Edwards Aquifer to be an underground river, therefore regulated by the state

Later that year State Court invalidates TWCs determination

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History continued Nov 16, 1992 Trial begins in U.S. District

Court for Sierra Club lawsuit. Jan 30, 1993 – U.S. Dist. Judge Bunton rule

for the Sierra Club and orders:Springflow must be maintainedTWC must submit plan to court by March 1993

to assure Comal & San Marcos Springs do not drop below Jeopardy levels

USFWS must develop springflow thresholds for take & jeopardy

Tx Legislature must develop regulations to limit withdrawals by May 31, 1993.

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History continued May 30, 1993 – Texas Legislature adopts

SB 1477 that creates the Edwards Aquifer Authority (EAA) with a 9 member appointed board

Aug. 30, 1993 – U. S. Justice Dept. ruled legislation may have violated the Voting Rights Act, in November they determined it did

Feb. 1994 – Fed. Court Appointed monitor to gather information for the court.

Hydrologic

Less storage in aquifer (1ft of head = approx. 35,000 acre feet).

Low flows of San Marcos Springs occur sooner during critical dry periods.

Greater potential for saline water intrusion during critical periods.

Ecological

Lower flows would possibly jeopardize listed species sooner.

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Threats to the system Historic lows vs. recent time (recharge &

discharge) Increasing water use Aquifer Storage & recovery Proposed policy to raise pumping caps Proposed policy to limit minimal pumping

required during drought

Summary

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Detailed studies (Past & Continuing)

Texas Blind Salamander - Typhlomolge rathbuni Two blindcatfish from San Antonio area: Satan

eurystomus & Trogloglanis pattersoni (Ictaluridae)

Distribution of species throughout the aquifer, important in showing hydrologic relationships

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Studies currently underway

Water Quality - investigating freshwater/saline water interface

Modeling of groundwater hydrology and the effect of pumping

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This system is a microcosm of problems in our world

Population growth and human demands threaten the system and the surface ecosystems (springs) it supports

We should educate the users of water from the aquifer about its dynamics

Its importance as the habitat for a community of organisms

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Additional studies needed

Biomagnification of contaminants up the aquifer food chain

Toxicity studies of specific members of the aquifer community

Additional studies of rarer species Energy flow and sources in the deep

confined aquifer

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Acknowledgements The work on the aquifer through the years

has been supported by USFWS, TPWD, USDA, USEPA and numerous other sources too numerous to mention.

Staff of the Research Center, Graduate Students, Collaborators and numerous others have assisted in developing the information about the Aquifer community.

Texas State University has been very supportive of this work.

Thank you!

I can be reached at the following: email: GL01@txstate.edu EARDC homepage:

http://www.eardc.txstate.edu Phone: 512-245-3581 Fax: 512-245-2669 Feel free to contact me with questions.