CAMN Hydrology Class Notes
The Meadows Center for Water and the Environment
San Marcos, Texas
March 7, 2015
Dakus Geeslin – Aquatic Ecology and Management
Aquatic Scientist – Texas Parks and Wildlife Department
Water Resources Branch
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San Marcos River: oldest inhabited freshwater system in N. America
Long strands of grass-like vegetation: wild rice
Small eye and sharp nose shiner are federally endangered – need long stretches of river
o Pelagic spawners
o Lubbock area
o Too much water withdrawal from surface waters
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Golden algae used to cause fish kills
o Thrives in cool-water conditions, low flow, high salinity
o Colorado, Red River
o Primarily caused by low inflows
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Blue-green algae
o Don’t let dog in the water
o Toxic to animals if ingested, central nervous system
o Can be caused by agricultural runoff
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Coastal systems
o Need nutrients, sediments, volume of water
o Red Fish is the state coastal fish
o Salinity too high for plankton, benthos, leading to reduced food for crab, fish,
and eventually Red Fish
o Takes years of observations to see what has happened to the food chain
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Biggest water users
o Agricultural
 Drip technology is the way of the future…many farmers are using that
now
 Are we learning from Israel or other countries with good ag practices?
 Dryland cotton farming
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Rice farms are still going – some have senior water rights, some sold
seniority to LCRA
o Residential is relatively low, but landscaping uses a lot
o Industry is finding water efficiency methods
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Groundwater conservation districts
o Users having to pay for water now
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Reuse
o Treated wastewater
o LCRA going to take Round Rock’s treated waste water and put it back into the
system
o Some stigma there, but not that different from what we already do
o Big Spring: Direct Reuse
 Wastewater to drinking water
 Comingle treated wastewater with raw water (which is salty)
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Texas water law
o Groundwater and surface water link is not recognized
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Flooding
o Some tree and fish species are dependent on flooding
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Subsistence Flow = life support
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CFS = cubic feet per second
o Measurement of flow
o Use an acoustic doppler to measure
o Depends on width of the channel
o Rating curve, based on depth
o 3 – 5 years to develop a Stage:Discharge relationship
o Signal from a bridge to ping down to the bottom
o Pick a representative point, so you can get a point in time
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Oxbows
o Important habitats
o Spawning areas
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Cypress Trees
o Some are 1000 years old
o Not recruiting as well, because of poor flows
o Recruitment: Reproduce, thrive into a next year class
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Instream Flow studies
o Guadalupe, Trinity, Brazos
o Basin Water Masters monitor stream flow
o Future water rights are bound by flow restrictions
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Tim Palmer Quote
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Like on Facebook: Texas Rivers & Streams – Texas Parks & Wildlife
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Water rights
o Very valuable
o Database that keeps track of values
o How do you monitor water use for ag?
 Either have surface water right or a groundwater well
 No groundwater conservation district in every county
Beth Bendick – Wetland Ecology and Management
Conservation Ecologist – Watershed Conservation,
Texas Parks and Wildlife Department
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Indicator species
Linear wetlands
o Regulated as a water viewess
o Might be called a stream, might be called a wetland
o Even with no water in them year round, as long as they connect downstream,
they can be regulated by the US Army Corps of Engineers
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Converted for agriculture
o Could be a regulated wetland, although there are exemptions for agriculture
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Hydric soil: Soils saturated with water become anaerobic, changing the iron content (for
example) and the quality of the soil
o Soil mottling
o Reduced iron: gray color
o Oxidized iron: rusty color
o Sometimes happens when roots get into the soil and provide oxygen
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Plant adaptations for dealing with saturated soil conditions (buttressing, etc…)
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Lost half of the wetlands in Texas since the 1700’s
o Filled in because they were seen as a nuisance or not as valuable as land
(mosquitoes, etc…)
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Rick Rack: Piles of rocks used to prevent erosion
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Permitting: first have to try to avoid the impact; if not, then have to minimize; if can’t do
that, then you have to mitigate – can also buy credits through mitigation banking
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Army Corps Definition of Navigable: list of streams considered navigable
o Sand and Gravel Program at TPWD: 30’ or wider; streams that were under a
Spanish land grant, state retained ownership over perennial streams
o Corps regulates tributaries under section 404: more like barges and large ships
o Corps navigable waters go on a list – basically has to be wet; TPWD waters are
done on a case-by-case basis
o Originally natural streams that have been channeled are still regulated even
though ecosystem function has beed degraded
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Ordinary High Water Marker: A defined channel that is regulated
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Section 10
General permit: <300 linear feet; pretty easy to get
Individual permits: larger, more complex projects
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Unit of measure of mitigation credits
o Ft. Worth uses Texas Rapid Assessment Method (TXRAM)
o Get an assessment, then multiplied by number of acres
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Indirect impacts are considered, but not directly involved in damage assessment
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Job market: mitigation banking is a growing industry
Ribbits is the website that logs all the mitigation banks around the country
o Wetland mitigation banking and stream mitigation banking.
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Larger site, more monitoring, more funds in the design. Endowment…higher likelihood
of success.
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Bottomland hardwoods: lost 2/3 of what we had pre-settlement
o Converted to agriculture
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River bends
o Outerbank: erosion
o Point bar: deposition
o Bend gets cutoff, creates an oxbow lake
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Pitcher plant bogs: East Texas
o Sandy soils, nutrient poor
o Carnivorous
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Playas
o Shrink swell clays that offer an opportunity for recharge to groundwater
o Heavily altered due to farming, CAFOs
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Riparian
o Has to have changes in vegetation and soils to be a riparian area and not just a
wetland
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Rio Grande Valley Resacas
o Oxbows
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Relative sea water rise: subsidence rather than sea level rise causing some of the change
Charlie Flatten – Water Conservation and Use
Water Policy Program Manager
Hill Country Alliance
Groundwater
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Barton springs comes out of the Edwards, Balcones Fault Aquifer
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Gallons per capita per day: includes residential (with landscaping) use, but not industrial
or power or any other categories
o Might be high per capita because of pools, watering the grass, etc…
o Statewide average is 150 gpcd
o Austin is about 148 gpcd
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West of I-35 corridor: lower supply, so better efficiency
“Dry Line”
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Where does CAMN water come from: Lake Austin or Lake Travis, Colorado R.
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Only about 10% of rainwater makes it back to reservoirs
o The rest is evaporated to the atmosphere or transpired through plants
o The further West you go, the lower the percentage
o Reducing evaporation: spread this material onto a reservoir surface, and reduces
rate of evaporation
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*Maybe it’s not best to be storing our drinking water in surface reservoirs
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Groundwater and surface water are connected, even though the state treats them as
separate
o Current water use: 40% surface, 60% from the ground
o When aquifers “leak,” you get a spring, and that creates surface water features
like creeks and rivers
o Aquifers that start at a high elevation and flow downward experience pressure
from gravity, and if possible, “spring” to the surface if offered the opportunity by
porous rocks
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Edwards and Trinity Aquifers are fast moving and sensitive, so pollution in the Trinity
Aquifer can flow into and affect the Edwards Aquifer
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Groundwater Conservation Districts are generally small and countywide; Board of
Directors is elected
o *Go to a GCD meeting and learn what goes on
o Austin is the Barton Springs District
o Public Comment is allowed
o Water wells in Hays county are threatened right now, so there has been more
controversy lately
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Groundwater Management Areas are aquifer wide, and GCDs are a part of those.
o Rural GCDs are not fond of having to export water to urban areas
o Unregulated spaces adjacent to GCDs are vulnerable to massive extraction from
water-intensive industries/users
Surface Water
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Surface water is owned by the state, rather than the landowner (as with groundwater)
o Appropriations: water grants (Spanish Land Grants from the 1700’s); older water
rights have seniority over younger water rights
o Highland Lakes: City of Austin owns most of those rights
o Rice growers have a younger water right, so growing has been cutoff
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Regional Water Planning Groups: manage the surface water
o *Great meetings you can go to
o People on the boards represent all different stakeholders: residential, industrial,
agricultural, power, manufacturing, etc…
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Reservoirs (dams): not that great of a way to store water
o Bad for ecosystems: disrupts water quality, estuaries, etc…
o No federal money
o Evaporate: more water than is used
o Fill up with sand
o BUT wouldn’t have enough water if there were no reservoirs
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Desalination
o Energy intensive and expensive
o Seawater
o Brackish (salty groundwater)
o San Marcos is on the edge of the brackish zone of the Edwards aquifer
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Reuse
o Straight from the effluent plant to the tap
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Aquifer Storage and Recovery
o Elpaso, San Antonio, Kerr County
o Pump into Aquifer when it’s dry
o Reduce evaporation
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Interregional pipelines
o Is it a long term solution?
o $1MM/mile – very expensive
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Conservation
o Low flow in our homes won’t be enough
o Land conservation is critical
o Landscaping is a waste of clean water
o 17 - 70% of water is lost from leaky pipes
o Rainwater could heavily reduce residential use, and it’s cheap infrastructure