The little fish that roared: the Endangered Species Act, state groundwater law, and private property rights collide over the Texas Edwards Aquifer.

• Author: Votteler, Todd H.

1. INTRODUCTION

   The Edwards Aquifer region has finally reached the point where the Aquifer is unable to provide for the needs of all those who depend upon it during dry years, from persons directly over the Aquifer, to those persons and endangered species at Comal and San Marcos Springs. Without a fundamental change in the value the region places on fresh water, a major effort to conserve and reuse Aquifer water, and implemented plans to import supplemental supplies of water, the region's quality of life and economic future is imperiled.(1) These words at the beginning of the order mandating federal management of the Edwards Aquifer on August 23, 1996 were the result of decades of political and legal stalemate over the sole source of water for San Antonio--the Edwards Aquifer (Figure 1).(2) Decades of disagreements among local, regional, state, and federal governments, five years of federal litigation, and one year of severe drought preceded the U.S. district court's attempt to protect endangered species dependent upon springflows from the Edwards Aquifer through a court mandated drought management plan.

   [Figure 1 ILLUSTRATION OMITTED]

   Management of the Edwards Aquifer has been a controversial and divisive issue for over forty years. Bitter conflicts have erupted between rural and urban interests, and between pumpers and those living downstream of its spring outlets who depend on springflows for their surface water. Some have demanded regulation of groundwater withdrawals, while others have contended that such limitations would violate private property rights under the Texas Constitution(3) and the Fifth Amendment to the U.S. Constitution.(4)

   The Endangered Species Act (ESA)(5) became the instrument that eventually brought state regulation to the Aquifer and the end to unrestricted withdrawals of groundwater. Across the western United States, the ESA implementation is clashing with the overutilization of water resources with increasing frequency.(6)

2. Description of the Edwards Aquifer

   The Edwards Aquifer (Aquifer) is a complexly faulted karst groundwater formation underlying portions of south-central Texas. It is the sole source of water for about two million people.(7) It supports the economy of San Antonio, the agriculture-based counties west of the city, and the communities in the Guadalupe River Basin all the way to the Texas Gulf Coast. The Aquifer flows generally east from the Texas and Mexico border to San Antonio and then feeds the Guadalupe River through Comal Springs and San Marcos Springs, both of which are home to federally listed, threatened and endangered species.(8)

   A simple analogy of the complex Aquifer likens it to a bucket with different sized holes from top to bottom that represent the springs. If the bucket is full of water, the water flows from all the holes. As the water level declines, flow from each hole decreases until the lower edge of each downward hole is reached, and then flow ceases. San Antonio, Comal, and San Marcos Springs are the major holes in the bucket. They are also the sources of rivers of the same name, all of which eventually flow into the Guadalupe River.

   The Aquifer is very transmissive and therefore dependent upon the highly-variable annual rainfall for recharge. During droughts, springflow from the Edwards Aquifer can become almost the sole source of flow downstream into the Guadalupe River. Comal Springs and San Marcos Springs are the two largest springs in Texas, as well as the southwest United States.(9) Normally, flows from these springs contribute a significant portion of the downstream flow to the Guadalupe River during droughts--81.7% at one point during the summer of 1996.(10) In years of below-normal rainfall and low recharge, withdrawals from wells are highest, thereby accelerating water level decline and reducing springflow.

   Approximately seventy percent of the recharge to the Aquifer occurs west of San Antonio in Kinney, Medina, and Uvalde Counties.(11) Across the Aquifer region, rainfall averages twenty-two to thirty-six inches annually, with twenty-two to twenty-nine inches falling over Kinney, Medina, and Uvalde Counties.(12) The average annual recharge to the Aquifer over the period of record from 1934 to 1997 has been 676,000 acre-feet (Table 1).(13) During the record withdrawal year of 1989, 542,400 acre-feet were pumped from the Aquifer.(14) Record high and low recharge amounts have been 2,486,000 acre-feet and 43,700 acre-feet.(15) In regions where the climate is relatively dry, such as the Edwards Aquifer region, runoff tends to be more variable than in regions that receive more rainfall.(16) The large variations in recharge make water supply planning extremely difficult in the Edwards Aquifer region. The challenge is made even greater in the absence of readily available water supply alternatives.

   TABLE 1. EDWARDS AQUIFER WATER FACTS AT A GLANCE(17) An Acre-Foot 325,851 gallons of water Average Annual Recharge (1934-1997) 676,000 acre-feet Average Annual Discharge from All Edwards Aquifer Springs 363,700 acre-feet (1934-1997)(18) Median Annual Recharge, 1934-1997 547,100 acre-feet Record Lowest Recharge (1956) 43,700 acre-feet Record Highest Recharge (1992) 2,486,000 acre-feet Record Withdrawals (1989)19 542,400 acre-feet A. History and Present Use of the Aquifer

   Humans have relied upon the springs for thousands of years. San Antonio Springs in San Antonio was visited by Cabeza de Vaca in 1535, and eventually supplied water for irrigation through acequias built around Spanish missions.(20) San Pedro Springs in San Antonio was established as a public park in 1729 by King Philip V of Spain, making it the second oldest park in the United States.(21) The Tehuacana Indians once occupied the Comal Springs area.(22) In 1845, German immigrants led by Prince Carl Solms-Braunfels settled in the Comal Springs area, establishing New Braunfels.(23) San Marcos Springs had been occupied by Tonkawa Indians for six hundred years before the Spanish arrived.(24) San Marcos Springs were also the location of a Spanish mission from 1755 to 1756.(25) Uvalde, Texas was established because of the existence of Leona Springs.(26)

   Even though the use of artesian wells from the Aquifer dates back to at least the 1880s, the pumping of groundwater began in earnest during the 1950s.(27) Today the Edwards Aquifer supplies high quality water to urban, agricultural, industrial, and recreational users.(28) The quality and quantity of water supplied throughout most of the history of the region have been so high that San Antonio relied on the Aquifer as its only source of water. San Antonio has not built the infrastructure necessary to deliver or treat surface water needed to supply the city in the event of a prolonged drought or to accommodate future growth. Even though the city is located at the edge of a subhumid region, the cost of water in San Antonio has, until recently, been among the lowest of any major metropolitan area in Texas.(29)

   One of the fastest-growing uses of Edwards Aquifer water over the last fifty years has been irrigated agriculture.(30) Much of the irrigation relies on inefficient irrigation techniques. Because the cost of water to the farmer has been only the cost of the well and the energy to pump water from the Aquifer, few incentives have existed to encourage farmers to adopt more efficient irrigation methods.

   There is general agreement that somewhere south of the Edwards Aquifer downdip, a "bad water line" separates the area of usable groundwater from the area where wells produce water of unacceptable quality. The bad water line has not been precisely delineated. There is disagreement among knowledgeable persons as to the risk of this line moving as the result of withdrawing large quantities of water from the Edwards Aquifer during dry years. Research regarding the bad water line has produced conflicting conclusions. Both those who fear the intrusion of bad water into the freshwater zone and those who contend it is not a problem cite as their authority the same U.S. Geological Survey (USGS) publication that describes its existence.(31) The possibility of saline water encroachment has been a concern since a drought in the 1950s, when residents reported that some freshwater wells on the southern edge of the Aquifer experienced an intrusion of highly mineralized water. The bad water line exists in close proximity to both Comal and San Marcos Springs where endangered aquatic species reside.

   2. Threatened and Endangered Species

   The Edwards Aquifer is considered one of the most diverse aquifer ecosystems in the world.(32) Within the Aquifer, species exist that are found nowhere else and about which little is known. Species of unique blind catfish are occasionally pumped out of the Aquifer front great depths.(33) The U.S. Fish and Wildlife Service (USFWS) considers the Comal and San Marcos Springs ecosystems to have one of the greatest known diversities of organisms of any aquatic ecosystem in the Southwest.(34) This is due in part to the constant nature of the temperature and flow of the Aquifer waters that have created unique ecosystems supporting a high degree of endemism.(35) At Comal and San Marcos Springs, one threatened and seven endangered species, which live in the Springs' openings and in the rivers and lakes originating from the Springs, have been listed by USFWS. The San Marcos salamander (Eurycea nana) is listed as threatened. The San Marcos gambusia (Gambusia georgei), Texas wild rice (Zizania texana), fountain darter (Etheostoma fonticola), Texas blind salamander (Typhlomolge rathbuni), Comal Springs riffle beetle (Heterelmis comalensis), Comal Springs dryopid beetle (Stygoparnus comalensis), and Peck's cave amphipod (Stygobromus pecki) are listed as endangered.(36) The fountain darter and Comal Springs riffle beetle are the only species listed at both Comal Springs and San Marcos Springs. The USFWS recovery priority for each of...