Driving out of the Ladybird Johnson Nature Center, as you head towards the Mopac Expressway in Austin, you must have come across the sign that informs you that you are entering the sensitive Edwards Aquifer recharge zone. Why does the city have to put up this sign to enlighten drivers, you wonder with a shrug. Whatever that means to most regular drivers, I now know exactly why that sign is there after experiencing a fabulous workshop with the Texas Parks and Wildlife this summer studying up close the meanderings of the Colorado river through Austin all the way to the Gulf of Mexico at Matagorda Bay.
Groundwater to the Gulf was an exciting seven day adventure specifically arranged for educators to understand, appreciate and then educate the children about the importance of water in our community and how it is shared and used to meet all needs, and to teach the ways of being an aware individual towards its conservation for the present and the future generations of all living things, including humans.
Visiting Austin was always a pleasurable trip for me with all that the beautiful city has to offer. But now, after my wonderful explorations of its natural realities with the Texas Parks and Wildlife crew and the Lower Colorado River Authority team, Austin is a city gingerly sitting on a very sensitive earth surface perforated like old cheese! How carefully we treat the city’s soil and how responsibly we use its waters goes a long way to shape the quality of water that flows down the Colorado river flowing through the city on its way to the ocean. It is a vital part of a fragile ecosystem and the city’s residents and visitors play a very significant part in protecting it.
Walking down a local park or along the banks of a stream that feeds into the Colorado, a curious observer may often spot little holes on the ground. These are sinkholes, little passageways that connect to the river. As a careful and responsible observer, the first “no no” is to never stick your hand or finger into those holes because they are the naturally air conditioned homes to many of our slithering friends that curl up into them or under an adjacent rock to feel the breeze that gushes out. The best way to study these holes is to throw a tiny stone into them to make sure no creatures are nesting there. Then gently lower your palm near the hole to feel the cold air emanating from it.
These sinkholes, thousands of them, in various sizes and structures are part of the Edwards Aquifer, a porous limestone formation that soaks in rainwater to hold the groundwater. That is the process of “recharging” or filling up the huge underground water storage called the aquifer. The Edwards Aquifer is made up of a particular kind of hard limestone, called Karst limestone which has the old cheesy look, full of honeycomb passageways caused due to eroding water. It holds water like a hard sponge. Besides sinkholes, the region also has underground caves and faults caused by earthquakes millions of years ago. The aquifer also has flowing artesian wells where the water between rock layers are pushed into the Colorado river. Many of you must have been to the Barton Springs located inside the famous Zilker Park for a cool dip in the summer days. That is exactly where an underground spring is gurgling water upwards into the river providing a constant supply of fresh water!
Until recently, scientists and city officials in Austin believed that these sinkholes sucked in rainwater or run-offs from over-watered lawns and filtered it slowly through the porous soil and eventually ‘cleaning’ up the liquid of city pollutants before finally storing in the aquifer. A simple experiment soon proved how wrong they were. Scientists decided to pour safe non-toxic dyes, of different colors, into various sinkholes around the city to identify the time taken for it to flow to Barton Springs. They put receptors in various wells and springs throughout the area to detect the dye. It was a shocking discovery that colored water appeared at Barton Springs in less than three hours! Some passageways took up to three days to deliver the water over a twenty-mile stretch. That is surprisingly quick, barely any time for the earth’s layers to do any cleaning up! Which clearly meant that the quality of water that goes down the sinkhole hardly alters till it gets to the aquifer and finally the river. The river is also the source of the city’s drinking water supply.
Therein lies the responsibility as citizens of Austin, or visitors to Austin to be watchful about what pollutants we leave on earth’s surface in that region that eventually gets washed by rain into those sinkholes. Now available is a detailed map of the recharge zone demarcating areas by groundwater travel times, the faster the water flows, the more responsible you have to be.
A nonchalant dog walker along the trail in Zilker park or anywhere in a city neighborhood may not care to pick up after their dog. The nitrogen-rich poop full with bacteria sits on the grass and gets washed into the groundwater. Avid gardeners and lawn owners may choose to put the most advertised inorganic fertilizer or pesticides and water their garden way more than necessary, with all excess water rushing into nearby sinkholes or river basin along with the toxic chemicals. Ignorant car owners often wash their car in their driveway adding significant amount of pollutants into the storm drains too. An unsuspecting driver can discard used motor oil by the side of the road. Even a leaking gas tank of a passing car on the freeway leaves its hydro-carbon trace on the road, to be added to the groundwater after a rain. Plain littering by city people is by far the most common way of leaching unwanted chemicals into the aquifer. A construction site can wash up too much of precious topsoil or concrete debris into the groundwater. A factory can release huge quantities of effluents that get washed into groundwater too. But the construction sites, factories and fertilized yard are easily identifiable as polluting sources, and are labeled as ‘point’ sources. The trouble often comes from the otherwise benign ‘non-point’ sources like cars, people and animals that leave a pollutant just about anywhere on the surface and are very hard to curb. Educating the individuals seems like the only possible way of curbing such pollution.
As part of the Groundwater to the Gulf training, we went into a surface cave with experts in full gear. Austin TV channels covered our daring feat as we slowly climbed into a low-roof, yet roomy cave where rattlesnakes may hiss at a curious trespasser. With headgear in place, the lamp showing our way, we squeezed through stunted stalactites and stalagmites stumps, heaving and pushing, shoving and help shove our not-so-thin bodies through nooks and crannies. In spite of elbow and knee padding, we were left with a few scrapes and bruises and emerging back into the daylight was exhilarating. That night, it rained wildly, and watching the gurgling flow of the torrential rainwater on the ground, I imagined that cave in full spate, pumping water into the passageways all the way to the trenches ending into the Colorado.
Next morning, we were safely into our gumboots, wading in knee deep water of the river testing the water to watch for nitrogen compounds, phosphates and sulphates, testing the turbidity (visibility through the water), and observing the quality and diversity of organisms in the water. Fortunately, in spite of the huge runoff from the night before, the water audit did not show very high proportion of nitrites and nitrates – a very positive sign that the neighboring house-owners may have restrained their fertilizing habit. The biodiversity in the spring water was good, with oxygen levels between 4-12 mg/l. We learned to study the temperature and pH at various points of the river from our canoes and reflect on the overall water quality.
Why is the aquifer so environmentally sensitive, you may ask. Especially, in the case of Edwards aquifer, the karst limestone (full of holes!) has little soil to filter out pollutants. Not all aquifers have such porous land surface. So, the good part about that is the surface water gets enough filtration during its trip to the deeper layers. The not-so-good side of the story says that the aquifers that fill up very slowly can run dry if not used with caution. The Ogalala aquifer from which originates the mighty river Colorado further north is one such aquifer facing a serious threat of overuse and slow refilling.
In a half-hour clean up drive, about forty teachers ended up collecting a huge amount of trash along the rivers bank right around the Barton Springs! The most common item was cigarette ends! That clearly indicated that the adult visitors have not been very responsible. The Zilker Park area is a fond retreat for many pet dogs. Unfortunately, most dog owners are not responsible enough to clean up after their pets! We also found juice boxes, ice-cream sticks and confetti indicating partying habits by the affluent neighborhood visitors. Again, an unexpectedly irresponsible behavior from the haves in society!
Next time you visit Austin, make sure to include a trip to the Beverly Sheffield Education Center, also called the Splash Exhibit. It is located right next to the Barton Springs and offers a fun, exciting experience that shows how the Edwards Aquifer was formed and how it maintains its average daily flow of 32 million gallons of water at the Barton Springs!
The second part of our trip was in the Matagorda Bay Nature Park where Colorado gently merged with the sea. An aerial view will reveal a reddish influx of water deep into the bay. That indicates a huge quantity of silt deposition by the river. Upriver, there must have been enough human activity to cause so much erosion of top soil. To contain the sediments from spreading into the bay, a rock wall has been constructed to preserve the oyster creeks in the region and the coastal navigation channels.
A visit to the beach as an educator is so strikingly different than as a tourist. Studying the fishes, the flora along the edge of the waves, beachcombing for litter and debris, dune monitoring observations where the shrub line ended and how the encroaching sea tides interacted with the living and the non-living things along the shore took all our attention. Educating ourselves to be more observant of the little details and the tell-tale signs of environmental change was like a blessed experience, motivating us to impart the knowledge to the growing and receptive minds of our young students.
Straight from the beach we headed for the salt-water marshes along the coast! Oar and personal GPS’s in hand we were an excited group of adults marching through the trails to the rippling waters that beckoned to us from behind the brushes. Water quality testing was a breeze with our training in Austin. The speedboat trip in the oyster creek was exhilarating as we dredged the bottom for oysters with a special rake. The adventurous ones cracked open the oysters, placing the jellied animal gingerly on their tongue and feeling the throbbing heart as it made its way down the esophagus!
Did you ever know that a humongous amount of cargo in America does not travel from one part of the country to another by the trucks you see on the freeway? Since the time of the native Americans, and as pictured in the books of Mark Twain, rivers and other waterways have been a very good alternative to sending freight by land. It is fuel efficient, and does not clog up road traffic. All along the Gulf of Mexico, from the southern tip of Texas to the Florida Keys you can go through a canal that runs parallel to the shore, separated from the vagaries of the sea by an elevated ridge. This canal keeps navigation safe throughout the year irrespective of weather conditions. The locks look like moats to an ancient castle and the massive lock gates that opened and closed as needed, were like robotic giants that work on clock-work precision and provide extra protection to the cargo ships during rough weather. A field trip to the lock gates revealed so much about the trade routes along the gulf and the adventurous lives of the crew that operate the ships along the canal and up the Mississippi all the way to Minneapolis!
Deep in the night, following a fabulous dinner at K-2’s, we were all huddled in the gazebo at the Matagorda County Birding Nature Center for an interesting session of amphibian watch. We learned the croaking of various native frogs as our trainer hooted and croaked with immediate responses from her jungle friends lurking all around. Then it was our turn to creep on the nearby waterbodies to identify the frogs by their calls. Seeped into the pristine darkness of the forest, a silent crowd of wide-eyed teachers hung out at the water’s edge eves dropping in nature’s private conversation. We were speechless in wonder.
After many brainstorming sessions, and exciting hand-on learning, we were ready to head home, wiser than ever. Water-wise we surely were! Role playing as a droplet of water, I now know that most of my real droplet partners are running between the cloud and the ocean in the watercycle as they evaporate from the ocean and return to it as rain. Only a few are lucky to do the land trips to the surface, runoff to rivers and lakes, seep into groundwater and travel up the roots of plants to transpire through leaves. We played ball with a globe and each time most of our fingers touched the blue oceans on the map. This means, we actually have very little sweet, fresh, usable, potable water that is suitable for human use!
We went home wiser, knowing that Texas has only one natural lake – the Caddo lake. All the other lakes where you plan fabulous vacations are actually man-made reservoirs built on the Colorado river. We agreed that building dams for human convenience has its harmful effects on the surrounding ecosystem while boosting our economy. We learned about the fine balance of nature where needless watering of one’s lawn can lower the water levels of a lake far from home, tossing your plastic waste into the ocean can kill an innocent turtle, flushing your expired medicines down the toilet can endanger a delicate species you never knew existed and mess up the delicate food chain! It was, in a way, very reassuring to know that we are all connected in a wide network of dependency. It felt good and I naturally became more caring.
Wherever you are living, what can you do to be a responsible consumer of water? There is a lot to be done. Look out for tips in the local newspaper, google water conservation techniques and most of all, prevent wastage of water in any way. Build a circle of friends that have similar interests and become proactive in your school or community. Most importantly, keep educating your parents and siblings. A wise water habit will go a long way to protect your health and guarantee some good water in your faucets for years to come!
