Landa Lake Habitat Rehabilitation

SWCA Environmental Consultants17 October 2013

Rick Howard

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

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

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

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

Into the Water We Go!

Into the Water We Go!

Invasive Species Removal

• Giant ramshorn snail (Marisa cornuarietis)• Armored catfish (Pterygoplichthys disjunctivus)• Tilapia (Oreochromis aureus)• Nutria (Myocastor coypus)

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

Removal Methods

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

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

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

http://www.google.com/url?sa=i&rct=j&q=&esrc=s&frm=1&source=images&cd=&cad=rja&docid=RHaK4K0bz7OtPM&tbnid=ENOPnprv52jjyM:&ved=0CAUQjRw&url=http://www.edwardsaquifer.net/geology.html&ei=TmRdUr2DE-3KiALvwoGIAg&bvm=bv.54176721,d.cGE&psig=AFQjCNHsIgLZyaTgPJa5_4DxjjcgxIzpww&ust=1381938608257534

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

Aerators

Data Sonde

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

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

Thanks

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

Questions ARE Welcome