Big Spring, Big Spring Preserve, Great Trinity Forest, Dallas. Above photo courtesy of Ben Sandifer [].

This past June, Texas Stream Team celebrated six years of phenomenal citizen scientist water quality monitoring at Big Spring in Dallas. Since 2013, Texas Stream Team citizen scientists in Dallas, whom are members of the North Texas Chapter of the Texas Master Naturalist, have been acquiring perfectly consistent, monthly water quality monitoring at one of the last free-flowing natural springs of north Texas: Big Spring at Big Spring Preserve. Never missing a single month through rain, snow and shine, the immense citizen scientist volunteer time (now amounting to over 1,300 hours) done by Ben Sandifer, Carrie Robinson, Richard Grayson and others have amounted to a better understanding of the natural spring which very well may have been a factor in prompting the settlement of Dallas.

Thanks to the very hard work of dedicated private citizens, citizen scientists and others, Big Spring has recently become an official Dallas Landmark: the first natural landmark in the City of Dallas.

Big Spring characteristics:
A site with profound Texas – and ancient – human history, Big Spring represents the crown-jewel of the largest urban bottomland hardwood forest in the United States – the Great Trinity Forest. In a city which, for a large part, has historically lacked a direct connection to its foremost human history and origins, Big Spring stands out as a resource which connects Dallas’ inhabitants to the city’s epic story of coming-to-be. 

While much of what brought Native Americans and pioneers to the current-day Dallas-Fort Worth metroplex may now lay underneath sprawling urban development, strip malls, and paved neighborhood roads, an iconic perennial flow from Big Spring remains thriving well into the 21st century as it is surrounded by a mostly native landscape of blackland prairie and Trinity River bottomlands.

Never ceasing flow during the drought of record in Texas (1950s) and during Texas’ most recent droughts, Big Spring pours out ancient water with a high residence-time within its mysterious aquifer beneath the neighborhood of Pleasant Grove. Like Pogue Springs, Big Spring has a consistent temperature that is close to the average annual temperature of the City of Dallas: 66.4 degrees Fahrenheit. Big Spring averages 65 degrees year-round. Texas Stream Team citizen scientists have affirmed the incredible resilience of Big Spring, a spring which has been conserved by the Pemberton family for nearly 140 years and is now under the assumed protection of the City of Dallas and watchdog advocates of the Great Trinity Forest. 

Carrie Robinson engaging in the Winkler method to determine the dissolved oxygen at Big Spring, Big Spring Preserve, Great Trinity Forest, Dallas. Photo courtesy of Ben Sandifer [].

The citizen scientists have not only poured in thousands of hours for water quality monitoring at Big Spring but have also rounded up other dedicated citizens to perform more costly radiocarbon-dating tests on the spring to obtain a better understanding of the age our precious natural resource. Adding E. coli and streamflow monitoring procedures to the suite of Texas Stream Team tests at the site, we have now learned that the spring initially discharges water free of E. coli CFUs and that Big Spring contributes tens of millions of gallons per year of some of the cleanest water found within its part of the massive Trinity River basin. 

Big Spring is the only spring in Texas monitored for both E. coli and flow on a monthly basis.

Interested in getting more out of your Texas Stream Team? Keep an eye out for an upcoming Advanced Water Quality Citizen Scientist Trainings for E. coli and other Advanced parameters by visiting the Texas Stream Team calendar at If you have any questions, please reach out to the Texas Stream Team at

The springs featured in the Springs of Texas Mini-Series with Alexander Neal area located on public lands owned by their respective municipality or county park system. Please observe the posted rules for the site when deciding to make a visit.
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