Water Quality Data

Master Naturalist Richard Grayson of the Texas Stream Team tests the waters of Big Spring in the Great Trinity Forest during monthly water testing
Master Naturalist Richard Grayson of the Texas Stream Team tests the waters of Big Spring in the Great Trinity Forest during monthly water testing

Big Spring has two data testing sites in conjunction with the Texas Stream Team. The sites are #80939 Big Spring Source at the contact horizon where the water first surfaces and #80965 Big Spring Crawfish Pond some 70 feet west from the source. Data is available for viewing and downloading in .txt and .csv format at the following links:

Big Spring Source:


Big Spring Pond:


The Texas Stream Team is a network or trained volunteers (Citizen Scientists) who gather information about the quality of Texas water resources and ensure that information is available to the public. Volunteers are trained to collect quality assured information that can be used to make environmentally sound decisions on a variety of issues. Currently hundreds of Texas Stream Team volunteers collect water quality data on rivers, streams, aquifers, wetlands, bays, bayous, and estuaries across Texas, including the Trinity River.

smu engineers without borders
Southern Methodist University Engineering Student Trainers test Big Spring’s water quality as part of SMU’s Engineers With Borders organization. These certified trainers teach neighborhood children how to conduct water tests in Dallas.

Trained Volunteers from the Texas Stream Team have been monitoring the quality of the Trinity River and water in tributary streams of the White Rock Creek watershed in Dallas since January 2005. Monthly monitoring at Big Spring began in June 2013 with a protocol of chemistry and E.coli testing.

The Texas Stream Team is based at Texas State University and is affiliated directly with The Meadows Center for Water and the Environment. The Stream Team is a partnership of agencies and trained volunteers working together to monitor water quality and educate Texans about the natural resources in the state. Established in 1991, the team is administered through a cooperative partnership with Texas State, the Texas Commission on Environmental Quality (TCEQ), City of Dallas and the Environmental Protection Agency (EPA).



Methods and Procedures

Protocols and quality control start with established procedures outlined in the Texas Stream Team Water Quality Monitoring Manual.

Each month assigned members monitor and report pH, temperature, dissolved oxygen, and other indicators of water quality to Texas State University and is distributed to project partners.

2013-2016 At A Glance

Data collection from 2013-2016 by Master Naturalist Richard Grayson, Texas State University Student Alexander Neal, Master Naturalist Carrie Robinson and Master Naturalist Ben Sandifer. Big Spring’s water team includes many faces. A thanks to all for their hard and often unrewarded work in this arena.

-Texas Stream Team has been monitoring monthly since June 2013

-Test sessions at two sites numbered 80939 and 80965. Data available online at Texas Stream Team website

-Monthly chemistry testing including E.coli protocols

-Average time in the field plus labwork is 3 hours per person, per month. It is a labor intensive and time intensive activity.

Water temperatures at Big Spring vary little at Station 80939 and 80965. These measurements are taken directly from the spring water itself. Ambient air temperatures during testing have varied from 102 degrees in August to 23 degrees in February.

Station 80939(Big Spring Source) which is the direct water source from the ground at Big Spring reflects a temperature similar to that of the average annual temperature in Dallas, Texas of 66.9 degrees. Big Spring averages 65 degrees year round. This water features high conductivity, low dissolved oxygen and a near steady 6.7 pH. This information suggests a high residency time of the water in the ground.

Station 80965(Big Spring Crawfish Pond) which is 70 feet from the source is exposed to the atmosphere and is a water column that passes through a wide array of aquatic plants and life before being tested. Residency time of the water in the pond is rather short as it moves through the outfall. Water exposed during the extremes of atmospheric temperatures can be impacted to some extent.

E.coli Testing At Big Spring

Coliscan Easygel is a method used to test for E.coli and general coliform bacteria. Easygel comes in a sterilized, two-piece unit, including a bottle of liquid medium and a petri dish treated with a special formulation. With this method, a 1 mL to 5 mL of sample of water is collected using a sterile pipette and introduced into a 10 mL bottle of sterile liquid medium. The prepared medium is then plated on a treated petri dish, and incubated at a temperature of 33 C for 28 hours.These tests are conducted on the east side of White Rock Lake in a laboratory space provided by For The Love of The Lake.

Commercially available incubators, such as the Hovabator, are recommended. Incubator temperature is maintained and verified with the armored thermometer used in the Texas Stream Team Core kit. Upon incubation, the general coliforms and E.coli produce enzymes that react with color reagents in the media to produce pink to red colonies (general coliforms) or dark blue colonies (E.coli). Two samples from each monitoring site are analyzed, and a mean value is reported.

ecoli 80939
Big Spring Source Site 80939 plates showing zero E.coli and coliform colonies. The source site has always shown zero E.coli bacteria.

Monitors typically use a 1 mL sample, but sample volumes may range in size from 1 mL to 5 mL. The Coliscan Easygel test can detect as little as one bacterial colony per sample, and can be used to identify up to 200 colonies/sample.

ecoli 80965
Big Spring Site 80965 E.coli sample. Evidence of heavy feral pig activity the night before resulted in a large E.coli count for the month

Concentrations exceeding 200 colonies/sample are recorded as too numerous to count (TNTC). A black and a white grid, which is the same size as the Petri dishes, is provided to assist monitors in counting E.coli colonies. Accuracy of Coliscan Easygel is based on the reasonable performance of properly stored, pre-treated sterile plates, media, and pipettes. This method is a reliable and valid tool for the detection of fecal contamination through a variety of concentrations.

Big Spring’s Source site 80939 is tested for E.coli using an 80cm narrow gauge copper pipe placed into the head of the spring. Results from 2013-2016 were zero for E.coli at this location.

Big Spring’s Crawfish Pond site 80965 is tested for E.coli by collecting a water sample from the pond 1 meter off the bank in the middle of the pond. Results from 2013-2016 varied wildly in E.coli colony forming units “cfu’s”. The amount of animal activity around the spring was the direct contributing factor to elevated  E.coli numbers. A number of animal species reside in and around the spring site which add E.coli and other bacteria to the water column. The water quality remains very good unless feral pigs migrate into the spring complex.

We are using the single water sample threshold for the EPA threshold levels noted in the graph. There is a lower cfu number for contact thresholds but is based on a 30 day mean. For example, in freshwater environments, 126 cfu (colony forming units) is the threshold for immersive human contact versus the 235 cfu for single sample testing for the same standards(see graph). Please note geometric mean calculation on graph as well.

Feral hog activity as evidenced by heavy rooting in and around the spring pond site was the direct contributor to high numbers of E.coli colonies at Big Spring’s 80965 test site over three years. High counts all reflect feral pig activity around the spring site.

Big Spring Flow Rate

big spring flow calculation
Big Spring Flow Calculation Table. Fill times in seconds to fill a standard 5 gallon or 4 gallon bucket with corresponding gallons per minute(GPM), liters per minute(LPM) and cubic feet per second(CFS)


Total flow averages from our data 2013-2016

2016- 37.2 gpm, (140 liters per minute)

2015- 28 gpm

2014- 22.8 gpm

2013- 23.4 gpm

There was a 32.14 percent increase from 2015 to 2016, which represents an extra 14,000 gallons per day increase in flow. Some of the wettest years on record, 2015-2016 provided exceptional flow at Big Spring.

Big Spring’s flow rate is calculated at the outfall of a pvc pipe located 75 feet from the spring source. The spring waters flow out of at least four known sources and aggregate in a pond/pool below. Measurements are taken below the aggregation point using a 4 or 5 gallon bucket. Timing is done with a stopwatch in a series of three timed tests with averages obtained at the end. That number is cross-referenced to the chart above with gives flow.


The spring contributes 11.5-14 million gallons of water into the watersheds of White Rock Creek and the Trinity River Basin annually. Big Spring is classified as a Magnitude 5 spring which discharges 10-100 gallons per minute.





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