Texas Springs: leaking into an uncertain future Chad Norris Water Resources Branch (512)

GROUNDWATER Supplied 59% of water used in TX in 2003 Population expected to double by 2060 GW level declines predicted for many aquifers over next 50 years (TWDB 2007) Impacts to groundwater dependent habitats (e.g. springs) unclear San Antonio Springs

What is a Spring? The natural flow of groundwater to the land surface or a surface water bodyThe natural flow of groundwater to the land surface or a surface water body Artesian or gravityArtesian or gravity Ephemeral, intermittent, or perennialEphemeral, intermittent, or perennial May form marshes, ponds, or streamsMay form marshes, ponds, or streams A springs characteristics is largely determined by hydrogeologic settingA springs characteristics is largely determined by hydrogeologic setting

Edwards Plateau Springs Edwards-Trinity (Plateau) Aquifer

Texas Springs Major and Historical Springs of Texas (TWDB Report 189) Documented loss and decline of Tx Springs 65 of 281 (23%) springs no longer flowed Only 2 of 4 largest springs remained

Texas Springs Springs of Texas Vol. 1, 1981 – Gunnar BruneSprings of Texas Vol. 1, 1981 – Gunnar Brune Describes about 2,000 springs from 183 TX countiesDescribes about 2,000 springs from 183 TX counties Further documented loss and decline of TX springsFurther documented loss and decline of TX springs

United States Geological Survey Springs (Heitmuller and Reece 2004)

Kerr Bandera Real Gillespie

Importance of Springs Recognized as valuable ecological, natural, and cultural resourcesRecognized as valuable ecological, natural, and cultural resources Barometer of local hydrologic conditions and watershed healthBarometer of local hydrologic conditions and watershed health Generally a source of high quality water – increases assimilative capacityGenerally a source of high quality water – increases assimilative capacity

Importance of Springs Water source for local wildlifeWater source for local wildlife –Often only perennial water source Significant component of natural flow regime in many streams – “baseflows”Significant component of natural flow regime in many streams – “baseflows” Unique aquatic habitats that often sustain high degree of diversityUnique aquatic habitats that often sustain high degree of diversity

Springs - Natural Flow Regime Often compose significant portion of streamflow – especially in arid westOften compose significant portion of streamflow – especially in arid west Provide baseflows to streams and riversProvide baseflows to streams and rivers –Sustain aquatic and riparian habitats during drought - perennial vs. intermittent –Historically reliable water supply –Primary source of recharge during drought –Affects property values

Gaining vs. Losing Streams Gaining Stream Losing Stream

Springs - Natural Flow Regime Kansas rainfall in/yr in West and in East GW use from High Plains Aquifer in west is high Gaining streams turned to losing streams (Sophocleous and Wilson 2000)

Springs - Unique Aquatic Habitats Transition between groundwater and surface water habitats – “Ecotone”Transition between groundwater and surface water habitats – “Ecotone” Thermally and hydrologically stable habitatsThermally and hydrologically stable habitats Commonly harbour rare, endemic, or relict speciesCommonly harbour rare, endemic, or relict species Provide refuge for common speciesProvide refuge for common species

Spring-dependent Fish Greenthroat darter (Etheostoma lepidum) Plateau shiner – Cyprinella lepida

Common Fish Species Mexican tetra (Astyanax mexicanus) Central Stoneroller (Campostoma anomalum) Longear sunfish (Lepomis megalotis) Green sunfish (Lepomis cyanellus)

Damselflies & Dragonflies Aquatic Macroinvertebrates of Springs Caddisflies Mayflies Beetles Snails Crustaceans True Bugs

Majority of Springs on Private PropertyMajority of Springs on Private Property –Recharge features and flow system rarely on same property Sustainable use of aquifersSustainable use of aquifers Texas water law does not adequately address GW/SW interactionsTexas water law does not adequately address GW/SW interactions –GW – Rule of Capture; GCD’s, GMA’s –SW – Prior appropriation Conservation Issues

Identify springs and gather baseline dataIdentify springs and gather baseline data More hydrogeologic information neededMore hydrogeologic information needed –Identify major outlets of aquifers and associated recharge features, flow paths, and residence times Address connected nature of GW and SWAddress connected nature of GW and SW –Require large-scale GW pumping to assess impacts on springs and SW Holistic watershed managementHolistic watershed management Outreach and educationOutreach and education How can we conserve springs?

Texas Springs: leaking into an uncertain future Chad Norris Water Resources Branch