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Flow processes in Spring Ecosystems

Flow processes in Spring Ecosystems. Glenn Longley, Ph.D. Texas State University Flows for the Future Conference October 31, 2005. Springs. Are important ecological systems They serve as the interface between groundwater and surface water

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Flow processes in Spring Ecosystems

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  1. Flow processes in Spring Ecosystems Glenn Longley, Ph.D. Texas State University Flows for the Future Conference October 31, 2005

  2. Springs • Are important ecological systems • They serve as the interface between groundwater and surface water • They often are refuges for species that have been isolated for long periods of time • As a result they often contain rare or endangered species

  3. Springs • Best documented in Texas by Gunnar Brune, 1981, “Springs of Texas” • Also Major & Historical Springs of Texas, 1975, TWDB Rpt. 189. • Comanche Springs in Fort Stockton have been used by native people, DeVaca in 1535 • By 1962 they were dry most of the time due to over pumping of the aquifer feeding them.

  4. Threats to Springs • West Texas – Consideration by Texas Land Commissioner to lease State lands for Water harvesting • Arid region with minimal recharge and more localized aquifers • Potential to dry many of the smaller springs in the region

  5. Threats to Springs • Central Texas Springs are threatened • In the SA Portion of the Aquifer all springs are threatened by inadequate trigger levels in Drought Contingency Plans to assure continued Spring Flow • Inadequate alternative supplies are being considered by major water users • Agricultural users have been allocated too large amounts of water.

  6. Threats to Springs • Barton Springs – High population growth and inadequate alternative supplies • Jacob’s Well – Large scale development that utilizes a limited aquifer that also feeds the well • Historic uses of springs is documented in Brune’s Springs of Texas

  7. Drought recurring but inadequately planned for • The drought used for planning purposes is the drought of the 50’s. but drought has been shown to be a recurring phenomenon in this region by the use of tree ring studies. • There have been droughts of longer duration and greater intensity.

  8. Methods • Field Measurements • Each Spring: • Latitude/Longitude • Water Temperature • Conductivity • pH • Dissolved Oxygen • Flow

  9. Methods • Collecting Water Samples • All water samples collected utilizing EPA and TCEQ guidelines for sampling and holding times. • Each site: • Nutrients • Metals; Se, Hg, As, Ag, Mn, Cr, Fe, Ca, Na, Mg, K, Si, P, B, Al, Sr & Ti

  10. Piper Tri-linear Diagrams • Major cation and anion percentages are plotted on the left and right ternary diagrams, respectively • Position of each is projected up into interior diamond-shaped field

  11. Ca Mg HCO3

  12. Stiff Diagrams Choza Frijole Na Cl Na Cl Ca HCO3 Ca HCO3 Mg SO4 Mg SO4 5 4 3 2 1 1 2 3 4 5 (meq/l) 5 4 3 2 1 1 2 3 4 5 (meq/l) Guadalupe Manzanita Na Cl Na Cl Ca HCO3 Ca HCO3 Mg SO4 Mg SO4 5 4 3 2 1 1 2 3 4 5 (meq/l) 5 4 3 2 1 1 2 3 4 5 (meq/l)

  13. Trans-Pecos Stiff Diagrams

  14. Ca Mg HCO3 Ca HCO3 Ca or Na - HCO3 or SO4

  15. The Next Step • Resample springs and locate new springs to sample. • Gather historic data on groundwater resources in the Trans-Pecos area and compare with data collected from this project. • Look at watershed, geologic and precipitation influences on springs, to better understand the groundwater sources of each spring.

  16. Biological Assessment • An evaluation of water-body conditions using samples of the biota in surface waters.

  17. History of Rapid Bioassessment Protocols (RBPs) • RBPs were developed in response to EPA efforts to find cost-effective approaches for assessing water quality and to develop standard biological monitoring techniques. • The first RBPs were released in 1989 as a compilation of various state agencies’ procedures and are continuously updated. • They were designed as a template for state agencies, which could make appropriate modifications for their area.

  18. Qualitative Sampling Methods • A D-frame kicknet is used for a 5-minute sample to collect 100+ organisms • The process is repeated one more time if it is not possible to obtain 100 organisms • If it is not practical to use kicknet then 100+ organisms are hand picked from stable substrate

  19. TCEQ Quantitative Metrics • Taxa Richness • Dipteran Taxa • Ephemeropteran Taxa • Intolerant Taxa • % EPT Taxa • % Chironomidae • % Tolerant Taxa • % Grazers • % Gatherers • % Filterers • % Dominance

  20. Metrics and Scoring Criteria (Qualitative)

  21. Post Spring Aquatic Life Use Scores Exceptional: >36 High: 29-36 Intermediate: 22-28 Limited: < 22 Total Score: 22 Aquatic Life Use Score: Intermediate

  22. Central Texas Springs • San Marcos & Comal • Home to several Endangered Species • Fountain Darter • San Marcos Salamander • Texas Wild Rice • San Marcos Gambusia • Smaller springs along the Balcones Escarpment – home to Plethodontid salamanders

  23. Thank you! I will be glad to take questions. • 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.

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