Presented by Rick Howard at the Texas Water Conservation Association Conference in The Woodlands, Texas - March 2014

1. Landa Lake Habitat Rehabilitation
SWCA Environmental Consultants
17 October 2013
Rick Howard

2. Introduction
• The Edwards Aquifer and Landa Lake
– Artesian aquifer system servicing drinking and recreational water
needs of San Antonio, Austin, San Marcos, and New Braunfels
– Recharge and contributing zones are generally associated with
the Texas Hill Country
– Provides habitat for several endangered species
• Edwards Aquifer Authority is the organization responsible
for management decisions
– Agency established by the Texas Legislation
– Collects fees from water users (e.g., municipalities, industries,
private landowners)
– Balances the needs of users and wildlife

3. At-risk Native Species
Common Name Binomen Listing
Status
Fountain darter Etheostoma fonticola Endangered
San Marcos gambusia Gambusia georgei Endangered
Texas blind salamander Typhlomolge rathbuni Endangered
Comal Springs riffle beetle Heterelmis comalensis Endangered
Comal Springs dryopid
beetle
Stygoparnus
comalensis
Endangered
Peck’s Cave amphipod Stygobromus pecki Endangered
Texas wild rice Zizania texana Endangered
San Marcos salamander Eurycea nana Threatened

4. Rehabilitation Activities
• Edwards Aquifer Habitat Conservation Plan
– Old channel restoration
– Flow split management
– Aquatic vegetation restoration
– Non-native animal species control
– Decaying vegetation removal
– Restoration of riparian zones and riffle beetle habitat
improvement
– Gill parasite control
– Household hazardous waste program
– Litter control and floating vegetation management
– Golf course management plan

5. Rehabilitation Activities
• Edwards Aquifer Habitat Conservation Plan
– Old channel restoration
– Flow split management
– Aquatic vegetation restoration
– Non-native animal species control
– Decaying vegetation removal
– Restoration of riparian zones and riffle beetle habitat
improvement
– Gill parasite control
– Household hazardous waste program
– Litter control and floating vegetation management
– Golf course management plan

8. Into the Water We Go!

9. Into the Water We Go!

10. Invasive Species Removal
• Giant ramshorn snail (Marisa cornuarietis)
• Armored catfish (Pterygoplichthys disjunctivus)
• Tilapia (Oreochromis aureus)
• Nutria (Myocastor coypus)

11. Primary Ecosystem Concerns
• Degradation of shoreline habitat – nutria
• Damage to native vegetation – all
• Displacement of native fishes – tilapia, armored catfish
• Consumption of endangered species – all
• Competition with endangered species – all
• Act as an intermediate host for exotic parasites – all

12. Removal Methods
• Nutria – live trapping and culling
• Armored catfish – spear fishing
• Tilapia – fyke nets and spear fishing
• Ramshorn snails – hand gathering

13. Progress in 2013
• 22 field days (Apr.-Aug.)
• Reduced detection of
exotics
• Removal of ≈2.75 tons
of biomass
• Increased detection of
natives fish species
Species Number
Removed
Mass
(kg)
Tilapia 2,099 1959.6
Armored catfish 391 424.4
Nutria 40 110.2
Giant ramshorn
snails
1182 7.7
Total 3,712 2,501.9

14. Water Quality Monitoring
• Water quality, quantity, and chemistry are critical to
aquatic animals
• Edward’s Aquifer drawdowns are likely to lead to
declined volume, velocity, and chemistry
• Provides a mechanism by which to track changes in the
environment and pollution
• Provides guidance for implementing corrective measures

17. Implementation
• Installed solar powered aerators
– Serve as an emergency measure in case of dissolved oxygen
(DO) drop
– Compressors are land based and on timers
• Deployed deep-water data sonde for DO, DO saturation,
turbidity, pH, conductivity, total dissolved solids (TDS),
temperature, and sonde parameters
– Telemetry allows 24-hour remote access
– Logged data stored on-line
• Requires monthly maintenance and calibration
• Monitor data for significant changes and trends

18. Aerators

19. Data Sonde

20. Results
• Continuous monitoring since 8 May 2013
– DO, % saturation, pH, conductivity, TDS, turbidity, temperature
measured at the sonde
– Battery voltage helps track weather conditions
– Current helps verify operability of the sonde
• All data (nine total parameters) collected at 30 minute
intervals
• Automated updates alert data users if pre-set values are
triggered

22. Data Set
• Data are displayed in graphical format as default
• Data can be displayed and downloaded as a
spreadsheet for further review
• To date, the probe has generated over 11,000 lines of
data with approximately 80,000 data points
• Generates a detailed data set that is continuous and
nearly real-time
• Requires little maintenance and is easy to operate

23. Thanks
• City of New Braunfels
• Edwards Aquifer Authority
• My SWCA team members

24. Questions ARE Welcome