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Craig Russell of Norman wades in the water Friday as he takes a break from fishing at Lake Thunderbird just south of the Alameda Drive bridge.
Craig Russell of Norman wades in the water Friday as he takes a break from fishing at Lake Thunderbird just south of the Alameda Drive bridge.
As the City of Norman braces for the possibility of a turnpike in the Lake Thunderbird Watershed, some questions remain about the lake’s future and the toll a turnpike could take on stormwater runoff in a major metro drinking water source.
A convergence of prevention measures and emerging studies on the condition and preservation of the impaired lake have some clean water advocates optimistic and others concerned about its future use and lifespan.
The Transcript interviewed nearly a dozen stakeholders on the issue, including the Central Oklahoma Master Conservancy District (COMCD), Oklahoma Water Resources Board, Oklahoma Department of Environmental Quality (DEQ), the City of Norman’s stormwater and utility directors and the Oklahoma Turnpike Authority (OTA).
The U.S. Bureau of Reclamation (BOR) owns the lake and contracts with COMCD to manage the resource. Norman uses the lake as its primary drinking water source, while Midwest City and Del City also rely on it in part.
Pollutants in the lake from stormwater runoff include phosphorus from fertilizer, nitrogen and chlorophyll-a, which are carried into the lake from Oklahoma City, Moore and Norman, water quality reports indicate.
Sediment, the soil carried into the watershed and lake, accumulates in the lake and impacts water supply over time. Clay and silt sediment create turbidity, or “cloudiness” of the lake.
These factors are the reason DEQ designated the lake as an impaired water supply, but that does mean the useful life of the lake is near its end, some experts say. The lake was created in 1967, and is predicted to last 100 years.
According to COMCD General Manager Kyle Arthur and DEQ’s Water Quality Division Director Shellie Chard, the lake appears to be in relatively good condition for its age.
“It doesn’t mean you’re not going to see a lake out here in 50 years,” Arthur said. “Yes, we’re in the second 50 years, but we’ve got time.”
Arthur added that some indicators are positive; the sedimentation rate is a “teeny bit lower” than predicted. “That’s good,” he said.
Chard said there is a spectrum of cautions issued for impaired lakes.
“If it were on the extreme end, we would be telling Norman and Midwest city and Del City, ‘do not use this water for drinking,’” she said. “We are nowhere near that. Then we kind of have an area where we would say it is impaired to a point you should not be swimming in it, fishing from it, so we don’t have that condition either. We have not stated that people should stay out of the lake, (issued) swimming advisories, fish consumption warnings for the lake. We don’t have any of that happening.”
However, conditions also do not appear to be improving, Arthur said.
A 2021 annual report based on monthly monitoring indicated that levels of pollutants that place the lake at risk are not improving, and in some cases, are worsening.
“It seems like we’re running in place,” he said.
Chlorophyll-a increased last year and is three times “the sensitive water supply criterion,” while progress on phosphorus levels stalled. Nitrogen has continued to increase in “past years,” a presentation of the report in May from the Oklahoma Water Resources Board to the COMCD board indicated.
Lance Phillips, program manager for Oklahoma Water Resources Board, said there’s no net improvement in the conditions.
“I was talking to one of my lake staff who’s doing the (lake) monitoring and he had been working on a trend report that basically kind of showed some parameters are getting better, some are getting worse,” Phillips said.
As a preventative measure, DEQ identified through a study in 2010 the total maximum daily load of pollutants that should be allowed to enter the watershed and lake from Oklahoma City, Moore and Norman. Since 2015, cities have been required to implement best management practices to mitigate pollutants from entering the watershed.
As part of those best management practices, Norman has implemented a fertilizer ordinance, requiring anyone who intends to use the phosphorus-rich chemical on their lawn to obtain a permit and perform a soil test. It also requires residents to refrain from blowing grass into roadways, which reach storm drains.
The Total Maximum Daily Load program requires cities to monitor stormwater runoff. Norman contracted with the Water Resources Board to conduct monthly monitoring.
Norman’s Stormwater Program Specialist Michelle Chao said the ordinances are difficult to enforce due to low staff, but the department follows up on citizen complaints and has two inspectors who monitor construction sites.
“We’d like to do more, but we’re really running on a shoestring budget,” Chao said. “It takes a long time and a lot of effort to get people to change their behavior. So, it might just be that we haven’t seen the results of those efforts yet.”
Now a five year study Norman has undertaken will answer the question: is the maximum daily load monitoring and best management practices program working?
Chard said the first round of five-year data is expected to be published within 6-12 months. The monthly reports could indicate mixed results based on factors like increased development.
“There are different ways to look at it,” she said. “We’re not seeing a lot of improvement, or maybe we are seeing a lot of improvement, but we’re having so much additional development that the (results) are staying in the same realm. I don’t know the answer to that. Thunderbird is a very large body of water and it’s going to take a lot to make a change to water quality.”
In additional efforts, BOR and COMCD intend to study the future water supply yield. Arthur said the agency will study drought as far back as the 1700s and examine historic climate impact like lengthy drought periods to water supply.
COMCD Board President Amanda Nairn said the lake will need to increase its water supply by 2060, and all eyes are on the city’s indirect potable reuse program. The city contracted with Garver Engineering for the pilot program.
The program means wastewater is treated and then discharged into the lake as a method to increase water supply.
“I think it’s our future,” Nairn said. “I think the pilot was wildly successful and I think that it’s something that Norman is going to have to do.”
Utilities Director Chris Mattingly said a report on the results of the study will be available later this fall.
“The team showed that they can treat very low numbers (of pollutants),” he said. “That’s using different amounts of electricity and power air chemicals. So, they (Garver) will be doing a cost analysis of, how low do we need to go and what will be that cost to compare to other forms of treated water.”
Nairn was concerned about how the city would pay for the program with the recent failure of the water rate increase election. As reported by The Transcript, voters declined to adopt the rate increase in April despite consistent adoption of increases in the last two decades. A study revealed a lack of trust in local government as a primary reason voters did not support the increase.
“I’m guessing the next step is how to pay for it, for the upgrades at the wastewater plant,” Nairn said. “To pay for those upgrades, it’s going to take a vote of the people – people saying yes.”
Mattingly said the city will make full use of grant applications to offset the costs. If successful, the impact of the indirect potable reuse program to extend the life of the lake could be worth the expense.
Early estimates indicated a reuse program could restore the water yield from 15,600 acre feet to 21,600 acre feet, he said. The yield dropped in 2013 for all three cities to 15,600 acre feet, Mattingly said.
“So, that would be very valuable,” he said. A caveat to the lake’s future yield and the program’s impact could be changes to that maximum number following BOR and COMCD’s yield study, which is underway.
Mattingly said the city received a matching grant from BOR for $148,000 to also identify a tool that would stop the city from wasting highly treated water if the lake is full and the city must release water from the dam.
“You wouldn’t want to treat high quality water and put it in the lake when you’re just letting it go over the dam,” he said.
With the emergence of OTA’s plans to construct a turnpike in east Norman in the lake’s watershed, questions about the amount of stormwater runoff that will be allowed and the measures it may take to manage it longterm are unanswered.
Conversations with OTA officials, city staff, DEQ, BOR and COMCD have begun. Those officials all say OTA is willing to consider constructed wetlands. Wetlands are built with plant life that naturally filter out stormwater pollutants before they reach the lake.
OTA Deputy Director Joe Echelle said the agency wants to be a good neighbor.
“I think that the Lake Thunderbird area provides a unique opportunity for OTA, and the City of Norman and the state parks to work together,” Echelle said. “We’re a new neighbor to the neighborhood and we’re interested in helping our neighbors.”
OTA has constructed wetlands for other projects before. Echelle said if done “right,” wetlands do not require maintenance outside of a removing beaver dam or other obstruction in the wetland.
However, Chard said a “huge” constructed wetland near a North Texas Water Authority reservoir does take maintenance to operate.
“They do take more operation and maintenance than people expect, because the plants will reach maximum uptake rate and sediment may clog the normal flow of water through them,” she said. “With some operation and maintenance, they can be very effective for a long time. It’s not like operating and maintaining a mechanical treatment plant, but it’s not just ‘build it and walk away.’”
It is not clear the size and scope of wetland that could be necessary for the OTA’s plans. Echelle noted OTA is still very early in the process of determining the impacts and response that would be required for stormwater.
He was skeptical that a wetland the size of Texas’ John Bunker Wetlands — 2,000 acres — would be necessary.
“Most of the wetland and areas that we have are somewhere in the neighborhood of 60 to 80 acres or less,” he said.
Echelle stressed that OTA is still in the very early stages of its 15-year long range plan, with the east Norman turnpike at the bottom of the list.
Chard said OTA has not requested any construction permits from DEQ for the Norman area, which it will need to proceed.
Nairn, who stressed that COMCD has taken a neutral position on the proposed turnpikes, reported that OTA met with COMCD, BOR and the state parks department in May.
“Bureau of Reclamation are the bosses here,” Nairn said. “A project this size has never come across BOR’s desk, so they’re learning as they go too. They laid out steps that OTA is going to have to do. They don’t yet have permission to cross the BOR property. They’re working on that.”
Nairn said BOR could deny OTA its request to cross into its territory, but if constructed, her chief concern would be ongoing monitoring during construction to ensure sediment and other pollutants do not enter the wetland.
OTA has said it will ensure proper controls are in place from the beginning to the end of the construction process. Chard said DEQ also inspects areas related to permits.
“We’re very, very early in the process, but Norman is being very proactive about it so, they’re on top of it,” she said. OTA would likely submit permit applications within six months of the construction date, Chard said. To date, DEQ has not received any applications.
Mindy Wood covers City Hall news and notable court cases for The Transcript. Reach her at mwood@normantranscript.com or 405-416-4420.
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