Tuesday, January 12, 2016

Edwards and Trinity Aquifer conditions, A Year In Review

No Drought
Lovelady well height: 524.60 ft-msl
Barton Springs: approximately 104 cfs 10-day average

          2015 began with some much-needed relief from Stage II Alarm Drought conditions. After rejuvenating rainfall in the preceding months, the Board declared No-Drought on January 29. Fueled by a stronger-than-usual El Niño phenomenon, heavy rainfall continued throughout the spring. A brief dry spell in summer was quickly overtaken by even heavier rains in the fall.  In a nutshell, 2015 was a wet, then briefly dry, then even wetter year.

          Steady recharge increased water levels in the Edwards and Trinity aquifers as well as Barton Springs and Jacob’s Well flow early in 2015. Aquifer levels continued an upward trend and received an even larger boost from extremely heavy rainfall on Memorial Day, as 5.20 inches fell on Camp Mabry. Total May rainfall in Austin reached a record-breaking 17.59 inches, topping the previous tally of 14.10 inches in 1895. The Hill Country and San Marcos received between 12 -15 inches. Rain temporarily disappeared from the region in July and August to round out the summer.

          Central Texas became perhaps more familiar than ever with the El Niño phenomenon, as 2015 boasts one of the strongest in history. As a result, the dry spell of summer was short-lived. An historic Halloween flood unleashed an astounding 18.5 inches in Buda, with surrounding areas reporting between 11 and 16. This event topped the previous Halloween 2013 and Memorial Day 2015 floods in stage level and discharge on Onion Creek. Antioch cave began taking desired recharge after storm runoff flows passed.

          In the 2015 Hydrograph (above, click to enlarge) includes three graphs depicting periods of above and below average rainfall at Camp Mabry during 2015 and the resulting effects on the Lovelady monitor well  and Jacob’s Well spring. At periods of above average rainfall, visible in the lowest graph, the discharge level at Jacob’s well spikes dramatically. Throughout the year, and at accelerated rates after rain events, the Lovelady Monitor well depth to water slowly increased.

          After continued rains through the 2015 Holiday Season, Texas remains drought-free as of January 5. The Lovelady well and Barton Springs drought trigger sites remain well above their respective average thresholds. The outlook for 2016 according to the National Oceanic and Atmospheric Administration is a still strengthening El Niño that could last into early spring. This perhaps being the strongest El Niño since 1997-1998.

On behalf of the BSEACD, Happy New Year!

Monday, November 30, 2015

What Makes a Good Monitoring Well?

Aquifer conditions are dynamic and therefore water levels can fluctuate because of drought, recharge, and pumping.  Monitor wells help track these changes and inform policy to help protect water supplies and spring flow for all users.  After all, groundwater is a shared resource.
We often get asked the question, what makes a good monitor well? In short, the answer is that a well that is representative of the aquifer we are interested in. But, while water levels can be measured in most wells, the nature of the geology and well construction usually limits the potential for a well to be used for monitoring purposes.
Diagram of a typical well headAt the surface, groundwater wells can appear  similar, however  individual wells--even neighboring ones--can be constructed in very different ways.  For example, different depths of wells, or different depths of the casing influences production rates and water quality.  Well records (e.g. driller's logs, geophysical logs, video logs) are key to understanding a well's construction.
Drillers use a variety of construction methods to balance sufficient quantity (yield) with good (a relative term) water quality.  The Edwards and Trinity Aquifers are each made up of many layers of rock.  Water quantity and quality can vary from layer to layer.  The location and depth of a well, and how it is constructed, determine what rock units that well can access and therefore influence its yield and quality. The construction of a well such as its casing depth, amount of cement, and/or packers can seal off undesirable layers. At the same time, the well is left open or screened at selected intervals to allow water to enter the well at the desired layers.
Every well should have a driller's log that documents well depth, well construction, pump setting, and an initial water level.  In 2003, all well drillers were required to submit this information online, so data on wells drilled in the last 12 years is much more accessible. In sensitive areas, a more detailed geophysical log is often required to inform the well construction and to limit the mixing of undesirable waters between aquifers (and into the well).
On the top of the well (called well head), most contain a 1/2" or 3/4" hole that can allows the measurement of the water level in the well (also called an observation port). To prevent debris or contaminants from entering the well, this port is usually plugged by a blue plastic square-head nut. The water level can be measured through that port using either an eline (electric measuring tape; reliable but time-consuming) or a sonic meter (bounces a sound wave off water surface; fast but requires verification).
District staff maintain over 30 continuous water level monitoring sites in the Edwards and Trinity aquifers. A pressure transducer and the cable installed in a domestic well with a drop tube.Many of the wells are domestic wells that are in use.  These sites are equipped with a probe (a pressure transducer) that is programmed to measure the water level hourly.  Staff stop by to download the data about once a quarter, or more frequently for a specific study. These monitoring wells are plumbed with a drop pipe that keeps the pressure transducer and cable away from the pipe that brings water to the surface and the pump wires. Monitoring does not interfere with operation of the well.
Everyone benefits from an efficient monitoring network.  Optimal monitor wells are representative of the aquifer and area we are interested in learning about. Monitor wells need good construction information (logs) and must be readily accessible. Many thanks to all of the well owners who allow this essential access to water level data, respond to conservation requests, and responsibly use and maintain their wells.  We are all in this together.
Useful links:
Geologic diagram of aquifer layers (stratigraphic column)

Thursday, November 5, 2015

Pouring It On

             For many in Central Texas, the morning before Halloween was much more frightening than the holiday itself. An historic flood, larger than the previous Halloween 2013 and Memorial Day 2015 events, occurred as a large front of heavy rain and thunderstorms swept across the region early Friday.
USGS Stream Gage on Onion Creek at Twin Creeks Road:

Halloween 2013: Gage Height: 20ft; Discharge: 12,000 cfs
Memorial Day 2015: Gage Height: 22ft; Discharge: 17,000 cfs
Halloween 2015: Gage Height: 28ft; Discharge: 45,000 cfs

In Buda, the final rain total reached an astounding 18.46 inches. Surrounding areas, including Kyle, San Marcos, Wimberley and Onion Creek all reported between 11” and 16”. In addition to punishing rain totals, the storm generated three tornadoes and a great deal of property damage.

What made this flood so much more significant than the aforementioned 2013 and ‘15 events? In this case, huge amounts of rainfall were concentrated in a shorter period of time. In addition, the ground in Central Texas was relatively dry prior to this year’s Halloween flood than the months preceding the two earlier events. In dryer conditions, heavy rain doesn’t immediately infiltrate below ground; rather, there is a kind of shock from sudden intense rainfall which results
in surface flow rather than penetration. Potentially-devastating flash floods are sure to follow. 

On the other hand, the Highland lakes saw significant rises in water level, counter to perennial dread about its historical low water levels. Recharge to the Edwards Aquifer hit overdrive, as recharge sites like Anitoch cave (pictured below) submerged.

We recognize that this relief is accompanied by devastation. We’re grateful for the responders who helped evacuate those who experienced this downpour as a disaster. We send care and encouragement to those reeling from yet another assault on their homes and loved ones by extreme flood events.

For information on the response and resources available in Austin and surrounding areas, visit https://www.atxfloods.com.

In the wake of flood events, it may be necessary to take extra precautions like boiling drinking water from your private well. Take a look at https://www.fraserhealth.ca/media/Flood_PrivateDrinkingWater.pdf to find out more.

Friday, October 9, 2015

Texas drying up, despite historic rainfall

Great report on well monitoring and groundwater response to the lack of rainfall, KXAN!

Thursday, October 8, 2015

Barton Springs Flow and Aquifer Levels Turning the Corner.

No drought
Lovelady well height: 517.82
Barton Springs: approximately 91.3 cfs 10-day average

Shorter days and recent temperatures seem to indicate that even cooler temperatures are just around the corner. That’s good news for those who’ve had enough of the Texas summer, but recent weather reports reveal decreasing chances for rain and summer-like weather returning as October continues. According to Bob Rose, LCRA Chief Meteorologist “So far we’ve seen just the opposite kind of weather we typically associate with El Ninos here in Texas.” During the month of September we received a little over 2 inches of rain. That’s 2 more than we saw in the months of July and August combined. Even still, that’s hardly enough to last long in Central Texas and it undoubtedly shows in Barton Springs flow and Edwards aquifer water level, measured at the Lovelady monitor well. We’ve turned the corner from rising aquifer levels and increasing Barton Springs flow thanks to a very wet May, to a downward trend in both. With no recharge and the uncertainty of El Nino-like weather arriving anytime soon this trend will continue. Remember that even as we are not currently in drought, wet conditions in Central Texas rarely last long as the next drought is close around the corner.

Thursday, September 10, 2015

Hoping for Fall falls

No drought
Lovelady well height: 521.69 ft-msl
Barton Springs: approximately 99.3 cfs 10-day average

20150908_TX_trd.jpgAfter 26 inches of heavy rain and flooding in May and June doused Central Texas and recharged the Edwards Aquifer, the landscape broke out in green, floral gratitude. Months later, with barely a trace of additional rain (less than a half-inch in July and August combined), and with heat indices breaking the 110-degree barrier, things are drying out again. By mid-August, much of Central Texas was already considered D0 (Abnormally Dry), with several areas entering D1 (Moderate Drought), according to the US Drought Monitor website. With the majority of Central Texas now in D1 and D2 (Severe Drought) status, the National Weather Service Climate Prediction Center forecasts drought conditions will persist or intensify as we move forward. In just the week from September 1 to 8, the percentage of our state experiencing drought (D0-D4) conditions rose by 5.5%.

For those feeling a sense of déjà vu, we’ve definitely seen this pattern in Texas before. Drought cycles through our state, with at least one period occurring every decade in the 20th century. The Texas Development Board points out that we may be at the beginning stages of a similar trend to one we experienced from 2010-2011, as seen in this image from their article. The percentage of Texas experiencing Abnormally Dry or Drought conditions (D0-D4) in June of 2015 was relatively similar to May of 2010. If the past is repeating itself, we may be looking at an extremely dry time ahead. You can visit the US Drought Monitor to check conditions state and nationwide.

Screen Shot 2015-09-08 at 3.58.27 PM.pngThis year’s historically-strong El Niño may play a role in breaking our dry spell, Mike Halpert, the deputy director of the Climate Prediction Center, told KXAN. The El Niño phenomenon occurs when warming Pacific waters result in above-average rainfall and below-average temperatures, especially in the Southern US (more info here). Then again, John Nielsen-Gammon, the Texas’ state climatologist points out that “the phenomenon can also be kind of a dud in Texas,” citing that “the two most intense El Niños did not produce the greatest amount of rain, and only increased rainfall totals by about 5 percent above normal” (Statesman).

If El Niño does throw some relief our way, we’ll all no doubt be grateful. Regardless, it’s never the wrong time to take action to conserve our most essential natural resource. Dry conditions in August have resulted in low inflows into the Highland Lakes, Buchanan and Travis. The amount of water in the two lakes combined dropped from 78% capacity, 1.56 million acre-feet, on August 1 to 75% capacity, 1.51 million acre-feet, on September 1 (LCRA). Not only do these lakes supply drinking water to more than a million people, they provide critical support to industries, businesses and agriculture along the lower Colorado River basin. We can all do our part to help slow depletion during drought. The EPA, as well as conservation-minded sites like Planetsave.com, provide tips for reducing your personal water use.

Here’s wishing you a cooler, wetter transition into Fall on September 23rd!

Monday, August 10, 2015

Spotlight on Best Management Practice at Antioch Cave on Onion Creek

No Drought
Lovelady well height: 522.41 ft-msl
Barton Springs: approximately 87 cfs 10-day average

No matter where you happen to live, the fact is you live on a watershed. That is, as scientist geographer John Wesley Powell described, “that area of land… within which all living things are inextricably linked by their common water course and where, as humans settled, simple logic demanded that they become part of a community.” In other words, a watershed or drainage basin is a topographically unique area of land where all rainfall travels to the same destination. Central Texas is broken into several of these basins, many of which have recharge features that direct flow into the Edwards and other aquifers. You can use this tool from austintexas.gov to find out which watershed you live in, and how healthy it is.
Clean, natural recharge, in addition to healthy watersheds, is critical to replenishing all aquifers. Take a look at aquifer recharge in action at Antioch Cave, on the Onion Creek watershed about 1.3 miles west of Buda. Onion Creek is the main contributor of recharge to the Barton Springs segment of the Edwards Aquifer, supplying an estimated 45% of total recharge (BSEACD). While Antioch cave is the largest recharge feature on Onion creek, there are many features similar, but smaller that enable recharge. For example, check out Cripple Crawfish feature upstream of Antioch on Austin Water Quality Protection Land.
Antioch Cave, named after a nearby cemetery, is a particularly interesting recharge feature. It’s fitted with a sort of “self-filtration” system called a Best Management Practice, or  BMP. During the first portion of a rain event, water flushed into Onion Creek is more concentrated with sediments, bacteria, contaminants and other flood debris loosened while flowing over watershed terrain. To reduce the amount of these elements in water entering the aquifer, the BMP at Antioch, a boxlike, concrete structure uses two automated valves which open and close to divert contaminated water and allow desired recharge. Desired recharge is present in the latter portion of a rain event, after much of the contaminants and large debris, which could clog the cave and inhibit further recharge, have already washed out. So, the presence of this BMP structure reduces the amount of stormwater contaminants entering the aquifer through Antioch Cave. In addition, the BMP valve system also ensures continued flow along onion creek downstream of Antioch.Antioch BMP.JPG

If you’re wondering how well the BMP does its job, consider this. BSEACD studies have shown that during one storm event in January of 2010, the amount of sediment, nitrogen and phosphorus prevented from entering the aquifer through Antioch was 16,907, 128, and 47 lbs, respectively (BSEACD p.3-12). To put that in perspective, that’s 8.5 tons of sediment--almost enough to outweigh this diesel truck! And while nitrogen and phosphorus occur naturally in soil and water, excess levels can be considered a contaminant of ground and surface waters and lead to damaging health effects for wildlife and people. Most sources of excess nitrogen and phosphorus come from human activity, usually traced to agricultural activities, human wastes or industrial pollution

Since the late 1990’s, the Best Management Practices at Antioch Cave and elsewhere along Onion Creek have played a critical role in improving the quality of water recharging the Edwards Aquifer and enhancing the amount of water recharging the aquifer along Onion Creek. For more information on the origin of the Antioch BMP, as well as photos and diagrams from construction, take a look at these appendices from KarstPortal.org.

Wednesday, June 24, 2015

The Land of Perennial Drought Broken by the Occasional Devastating Flood

No drought
Lovelady well height: 513.8 ft-msl
Barton Springs: approximately 113 cfs 10-day average 

Since our last entry on May 7th, our hopes for much-needed precipitation across central Texas have been more than fulfilled. While benefits to the region are significant, BSEACD hopes for the care and recovery of all those who suffered great losses due to Memorial Day flooding.

After recent heavy rains, Hays, Travis and Blanco counties have experienced significant relief, as all have returned rainfall numbers above monthly historical averages for May and June. According to the district weather station, local rainfall totals reached 14.9 inches in May, 10.5 inches over the monthly average. As a result, the water level of Lake Travis has risen 45.2 feet since the start of 2015. During the month of May alone 36.5 feet of that rise occurred. The Lovelady monitoring well (an Edwards well used to determine the elevation and state of the aquifer) has risen 15.5 feet in that same time. Lake levels are at their highest since numbers reported in April of 2011 by the LCRA and the Lovelady well is at its highest elevation, 513.8 feet, since August of 2010.

The weather phenomenon behind the intense rains of the last several months is the much-talked-about El Nino effect. Bob Rose, meteorologist for the LCRA, explains: “El Nino refers to the warming of the tropical pacific waters between the coast of South America to just north of Australia. When these waters turn unusually warm and persist for quite a while, they tend to influence the atmosphere above them and eventually influence the jetstream all around the world. For us in central Texas, there is a fairly strong correlation between the development of El Nino and a pattern of above-normal rainfall.”

As this pattern continues, so far in June, the BSEACD weather station has reported 4.66 inches so far, 0.85 inches above the monthly historical average. Happily, the majority of Texas is now out of drought status, with a few small areas demonstrating “abnormally dry” conditions. For updated information on the drought status throughout Texas, refer to the United States Drought Monitor.

According to an unknown state meteorologist from Texas in 1927, “Texas is a land of perennial drought broken by the occasional devastating flood. “ We see this statement ring true as 2015 rolls into summer. That said, drought will always be a concern for our beloved home state, so let’s maintain our dedication to conserving our most precious natural resource, even in this time of plenty.

Thursday, May 7, 2015

Welcoming the Rain, Hoping for More in the Edwards' Recharge Zone

No drought
Lovelady well height: 498.71 ft-msl
Barton Springs: approximately 92 cfs 10-day average

Tuesday, May 5, brought heavy rainfall to areas throughout Central Texas. While central Texans typically welcome rain as a much-needed event, the specific locations that receive the rain impact the Barton Springs segment of the Edwards aquifer differently. Northern Travis County experienced flash flooding as a result of the rain with Bull and Walnut Creeks experiencing over 4,000 cubic feet per second (cfs) according to LCRA flow stations. We can generally say that significant recharge occurs when Onion Creek (in Southern Travis & Northern Hays counties) is flowing all the way across the recharge zone to Antioch Cave. However, Hays County received very little rainfall by comparison. Creeks within the critical recharge zone like Onion, Slaughter, Bear and Little Bear saw small increases in flow. For example, flow in Onion Creek (at Driftwood) rose from 25 cfs to 35 cfs from the rains. Antioch cave, the largest-capacity recharge feature in Onion Creek near Buda, did not receive any creek flow or recharge.

The Edwards Aquifer recharge zone provides direct inlets for recharging the aquifer. When rain falls in the watershed upstream of this critical area, especially in northern Hays County, streamflow provides sustained recharge to features like Antioch Cave and other sinkholes, which act as conduits directly into the aquifer. As a result, the water supply is bolstered and habitats for critters like the Barton Springs salamander are maintained.

Although the recharge was not significant to the aquifer as a whole, all things considered, Tuesday night’s rain helped keep Barton Springs flowing for Austin’s summer bathers and provided needed thirst-quenching for local plants and wildlife. The rains also helped continue the rise in groundwater levels seen in the Lovelady monitor well. For the year, the Austin areas is 0.3 in above average for rainfall. Less than a week into May, we’ve received almost a fourth of the month’s historical rainfall (0.97in of 4.4in) according to the BSEACD station. Let’s hope the rains continue to visit Central Texas and the Edwards Aquifer recharge zone is not left out.
The outlook for future rainfall looks promising as the National Weather Service Climate Prediction Center anticipates that with the wet start to the month across the plains, forecasts indicate an active southern stream and a generally wet pattern for much of the United States.

And to folks who encounter flash flooding, remember it’s always safer to turn around at flooded low water crossings!

Thursday, March 26, 2015

Creeks Flowing, Groundwater Rising in our Area

No Drought
Lovelady: 492.1 ft-msl
Barton Springs: approximately 92 cfs 10-day average

Groundwater levels continue to rise thanks to the overall rainy conditions experienced in March. Many area streams that flow over the recharge zone of the Barton Springs segment of the Edwards aquifer have seen several periods of prolonged flow, thus providing a relatively steady input to the groundwater supply. Except for one week in December, Barton Creek has been flowing since late November 2014. According to the USGS Onion creek gauge near Driftwood, TX, flow in the creek has not dropped below 20 cfs since the end of December. As it flows east over the Barton Springs Edwards aquifer recharge zone, Onion creek steadily loses water to the aquifer via fractures and karst features located in the creek bed, and by the time it gets to the eastern edge of the recharge zone, has lost all of its water to the aquifer. 

Despite the overall good conditions in the Barton Springs segment of the Edwards aquifer, it is important to remember that other parts of the state are still under severe drought and the we are very much at the mercy of where and when the rain falls. For instance, many of the lakes in the Highland lake system are far below their full capacity and the Edwards Aquifer Authority has a drought declaration in place.