Estimating water capacity, demand challenges Fort Smith board and city admin

Editor’s note: This is the fifth story in a series addressing identified Fort Smith water system replacement and repair needs with cost estimates that approach $600 million. Link here for the first story, link here for the second story, link here for the third story, and link here for the fourth story.

Pipes, water meters and other physical parts of the city of Fort Smith’s water system can be measured and priced, but estimating and prepping for future water capacity is difficult. The difficulty has frustrated Fort Smith Board members tasked with approving capacity-improvements.

Cost estimates, priorities, and funding continue to be hard to pin down in the ongoing effort by city of Fort Smith water system leadership to modernize and maintain the city’s water system.

Part of the discussion involves at least two key factors related to the water supply — the amount of water the system can handle, and the amount of water the system can treat. A surplus of capacity is not an asset if treatment facilities can’t meet the demand, and surplus treatment is no good if there is not enough capacity — water lines, water tanks, reservoirs, etc. — to distribute the treated water.

The issue is not new. A 2009 report from Burns & McDonnell estimated that water supply would be adequate but treatment capacity at Lake Fort Smith and Lee Creek will not be able to meet future water demand for the city and its wholesale customers. The aging treatment plant at Lake Fort Smith — located in Mountainburg — and aging water transmission lines from Lake Fort Smith to the city of Fort Smith were identified as a “critical vulnerability” as early as 2010.

The primary challenge for city administration and the Fort Smith Board of Directors tasked to approve water system plans and funding is how to best prepare for future demand. Modest planning could result in future shortages or strict conservation measures. And with the city being the primary provider of water in the larger metro, residents outside the city could also face shortages and conservation measures.

Aggressive planning could result in extra funds spent on treatment and capacity that may have been needed for other parts of the system.

The cost estimates also complicate the discussion. Water-treatment plants, and completion of a 48-inch water transmission line are estimated to cost between $328 million and $585 million, according to an August 2025 report to the board. That cost estimate does not include replacing aging water lines and modernization of water meters.

POPULATION, WATER DEMAND
A detailed 118-page water system master plan provided to the city in 2022 by Hawkins-Weir Engineers shows that the Fort Smith metro population is estimated to be 261,927 in 2040, up 6.64% compared with the 2020 population.

The population growth is outpaced by estimated increases in water demands. The report recommends the city plan for an annual growth rate of 1.5% for average daily demand and maximum daily demand. The overall increase in demand is estimated to rise 16% by 2035, with the increase up 35% by 2045, according to Barry McCormick, a principal with Hawkins-Weir.

“For the purpose of planning for future water infrastructure needs, an annual growth rate of 1.5% was selected for water demand projections,” Hawkins-Weir noted in the 2022 report. “This annual growth rate should be sufficient to account for a short-term increase in population associated with the selection of Fort Smith as the new Foreign Military Sales Pilot Training Center at Ebbing Air National Guard Base.”

McCormick said water usage rates do not always follow population trends. Usage patterns, including changes in large commercial and industrial users, will impact water demand.

“The difference in growth rates between population and water usage could be based on increases in the per capita water usage,” McCormick said in a note to Talk Business & Politics. “Assuming that Fort Smith is seeing an upward trend in the size of houses being constructed, you could see an increase in water usage because more houses have pools and/or yard irrigation.”

OTHER DEMAND FACTORS
Context about population and demand relationships sought from the city of Fort Smith somewhat mirrored that provided by McCormick and the 2022 report. The city said faulty water meters and weather changes also make demand prediction difficult.

“Water usage is not always directly related to population,” the city noted in a statement. “Industrial and commercial use can significantly impact water consumption. Additionally, under-reading water meters fail to record the actual water used and may give the impression that less water is being used than is actually the case. This can also lead to a higher amount of unaccounted-for water.

“Water usage is also influenced by the weather. The hotter and drier the weather, the more water is used for irrigation, filling pools, and other outdoor activities. That’s why we see a decrease in usage during normal winter months and a spike during summer. If the city has a wetter-than-normal summer, usage will typically be lower.”

Jimmie Johnson, the city’s deputy director of engineering, said in previous interviews that even with modest population growth, the city is getting closer to not being able to produce enough water to meet a maximum daily demand. He said “one really long, hot summer” could result in water conservation measures. Lance McAvoy, the city’s director of utilities, said water conservation measures, which are used by some cities to reduce demand peaks and manage capacity issues, are an alternative the board may be forced to consider if new transmission lines and water treatment systems aren’t installed and updated, respectively.

AGING SYSTEM
According to the city, the primary water transmission lines have “varying ages and materials.”

“Regardless of current population growth, the water transmission infrastructure supplying water to Fort Smith is aging and will eventually need to be replaced,” the city said in response to questions about capacity.

The 27-inch steel line from Lake Fort Smith was installed in 1936. A 36-inch line from Lake Fort Smith was built in the 1950s, with materials including concrete cylinder pipe and ductile iron pipe. The 48-inch line from Lee Creek was installed in the early 1990s. The lines connect with the two lines that cross the Arkansas River near the Midland Bridge. The 48-inch line in a tunnel under the river was build in 1953, and a 30-inch line on the bridge was built in 1968.

Fort Smith board members in recent years have been reluctant to approve rate increases or large capital outlays to fund water system needs. The board in August 2025 rejected an up to $48 million plan to buy new water meters, and in July 2024 approved only one of two recommended water rate increases. The approved increase, the first since 2011, increased the monthly bill by $2 for a majority of the city’s residential customers.