The purpose of this website is to provide a central source of data and resources concerning water issues of the Texas Hill Country.   The primary concern is welfare of the Trinity Aquifer (which includes the Glen Rose and Cow Creek aquifers and other formations), the Guadalupe River Above Canyon Lake and Canyon Lake
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 Canyon Lake holds 382,000 acre ft when the water elevation is 909 ft above sea level.
Right now, Feb 20, 2010, the lake level is at 909.2 ft after periodic heavy rains since early September

Prior to 1990, in all instances when the river dried up, both the Spring Branch Gage and Comfort Gage went dry on essentially the same day.  The Comfort gage is at I10, 60 river miles up stream from the gage at Hwy 311 near Spring Branch.   The Guadalupe is now a "losing stream" meaning the flow drops going downstream instead of gaining water from springs - the normal condition for the Guadalupe.  Even in the worst droughts of the 50s and 60s, the Guadalupe was a gaining stream until the 1990s when development and agriculture made greater demands on the Trinity Aquifer and the river itself. 

GBRA contends they own the water upstream of Canyon Lake since it eventually winds up there and sells water from their 90,000 acre ft per year permit to the likes of River Crossing Golf Course at Hwy 281 north of Canyon Lake.  How can they make such a claim when the water upstream  is not flowing into the lake but is used by others with senior water rights and water wells in the Trinity Aquifer?  (Flow is 17 cfs or 34 acre ft/day at Comfort on 09/02/09 and zero at Spring Branch) River Crossing buys 312,000 gallons per day (350 acre ft/yr) from GBRA and leases senior rights for another 100 acre ft per year from a man in Kendall County.  The court ruled in a case brought by the Guadalupe River Association that River Crossing could not pump if the river flow was less than 70 cfs.  So they use the senior rights they leased from Kendall County when the river is going dry - like right now.

When GBRA applied for an increase in their water permit for Canyon Lake from 50,000 acre feet per year to 90,000 acre feet, it was on the basis that this withdrawal, in addition to evaporation and riparian rights, could be sustained through the drought of record - 1949 to 1957.   It cannot.  The volume of water in Canyon Lake has dropped 110,000 acre feet in 1.3 years.  About 270,000 acre feet remain assuming the lake is not filling with silt from all the muddy floods we have.  So, with a clean lake bottom, no evaporation and GBRA getting ALL the water, there are 3 years of water left for them to sell without a big big flood to bail them out.

There is a graph below of lake level verses time that we generated using the day-by-day flow of the Guadalupe River from 1950 to 1960.  We assumed Canyon Lake existed and was full in 1950 (the lake was finished in 1965).    We allowed for evaporation of 5 feet per year converted to daily flow and a minimum release from the lake of 50 cfs for riparian rights in addition to GBRA water sales of 25,000, 50,000, 90,00 and no sale of water at all.   Under the old permit GBRA could sell 50,000 acre feet per year and the lake would have run dry a few weeks before the big rain.  The water runs out before 1955 if GBRA had sold 90,000 acre feet per yr from our hypothetical lake and the worst year of drought, 1956, was yet to come.  Try going 1 day without water delivered to your house.   (50,000 acre feet per yr was the Corp of Engineers estimate when the lake was built for FLOOD CONTROL AND WATER SUPPLY.  Not recreation.)

Note: there was a good flood in fall of 1952.  So when is a drought over.  Hard to say.

THE MAJOR DIFFERENCE BETWEEN THE 1950s AND NOW IS THAT MUCH MORE WATER IS USED UPSTREAM OF CANYON LAKE AND THE ESTIMATED LAKE LEVEL DROP IN EACH GRAPH IS VERY OPTIMISTIC.   If the upstream water use in the 50s had been what it is today the hypothetical lake would have dried up much sooner in each case.

We doubt GBRA delivered 90,000 acre ft on their Canyon Lake permit this past year.  That is an average 128 cfs release down stream all year.  Right now 60 cfs is being released of which 50 cfs we believe, based on past history, is riparian rights and 10 cfs is water delivered.  From 1996 to 2000 the average delivery of water against the GBRA permit was only 10,000 acre ft per year and the permit was for 50,000.  See commentary on this below the second graph.

Remember, the "drought of record" is just that.  Assuming a worse drought could occur has no basis legally as there is no record (100 years is a very short time in climate history so the law is faulty with no one at fault)  However, it is logical to assume it could be and in fact has been worse.  Wells are already going dry in the Hill County just 1.3 years since the lake started dropping.  A well north of Bergheim went dry in 1956 - rather late in the 7 year drought.  But then the water level in that well dropped 100 feet with only 6 families in the Bergheim area using water from the Trinity Aquifer.  Comal Springs went dry as well and the population of San Antonio was less than half what it is today. 

THE HILL COUNTRY IS 18 MONTHS INTO A SEVERE DROUGHT
IN 17 MONTHS CANYON LAKE HAS DROPPED  16-FEET 1-INCHES

CANYON LAKE IS DROPPING 15.5 INCHES A MONTH

In 2005/2007 it took 510 days for Canyon Lake to Drop 7.5-feet before it started filling again.  This year it has taken only 520 days to drop 16 feet and has been rising and falling with minor rain storms.  As pumping for crop/golf course irrigation and lawn watering began the lake has been  dropping faster in the absence of significant rain.

WHEN IS A DROUGHT OVER?

The graph below shows the drought of 1950-1960 ( http://hillcountrywater.org/water_available.htm  ) and a flood occurred in 1952 that would have brought the lake up 13 feet had it existed at that time.  (The lake was completed in the mid 1960's) The drought continued and the lake would have gone dry in mid 1954 taking 90,000 acre ft/yr, and in July-August of 1956 all useable water would have been gone when the big flood came in 1957 taking just 50,000 acre ft/yr. When the lake was designed the Corp of Engineers projected a sustainable supply from the lake taking 50,000 acre ft per year in addition to riparian rights and natural loss using the same data base used for this graph.  We will have to wait and see what mother nature has in store. 

I have always found it an amazing coincidence that the 40,000 acre feet added to the GBRA permit a few years ago equaled the amount of water they were NOT delivering in the 1990s.  From 1996 to 2000 the average water delivered against the GBRA permit for Canyon Lake was 10,000 acre ft/yr.  The  permit at that time allowed an annual diversion of 50,000 acre ft/yr.  50,000 - 10,000 = 40,000.  Could GBRA be selling the same water twice?   I am sure they plan to be retired or dead before the next major drought when they will be forced to anti up the water that will not be there.  I have visions of people storming the GBRA castle with torches and pitch forks after they have had to board up their homes and leave.  I am one of those people using Canyon Lake water.

People contemplating a move to the Hill Country any where in the Guadalupe River water shed upstream from Canyon Lake should be aware of the severe water problems in this area.   Depletion of the Trinity Aquifer in times of drought is already a fact of life and is getting worse as the population grows.  It is the Aquifer that feeds water to the river in the absence of rain - not snow capped mountains.  Floods fill the aquifer usually in May-June and Sept-Oct periods. 

Some wag suggested the Hill Country climate is one of perpetual drought interrupted by the occasional monsoon. Our floods are legendary but so are our droughts.  In the 1890s there was a drought comparable to the 1950s drought and one year droughts are common in recent history.

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If you have water data or a link to data that you would like posted on this website, please send this information to webmasters@hillcountrywater.org.  We welcome help in developing this website and making it as useful as possible to Hill Country residents.

In addition to water issues, links are provided that may be of interest to Hill Country Residents such as the TAMU information on Oak Wilt management.  

Updated 02/20/2010.

This site is maintained by
Stephen C. Grigory, PE
981 Brookside Dr
Spring Branch, Texas 78070

email sgrigory@grigory.com for technical comment or questions
email webmasterss@hillcountrywater.org concerning problems with the website.