Little Rock directors press staff on new stormwater manual as ADEQ deadline nears

City of Little Rock staff told the Board of Directors on March 4 that the city must adopt an updated stormwater drainage manual and associated MS4 permit by March 31 to meet Arkansas Department of Energy and Environment requirements, and that ADEQ has declined requests to phase in the new water-quality standard.

The manual, staff said, updates technical design methods first adopted in the 1980s, increases use of the modified rational method for detention design on larger sites, and sets a post-construction water-quality standard tied to total suspended solids. Brad, interim director, told the board the draft reflects “years of collaboration, compromise, and commitment” and that staff reduced an original recommendation to set the water-quality standard at “1.05 inches or the eighth percentile of total suspended solids,” which he said is the state minimum confirmed by consultants and DEQ. He said the city has spent about $331,000 so far on consultant work and related efforts.

Why it matters: the updated manual will govern how new development controls runoff and treats stormwater in Little Rock. Directors and developers said the new requirements could significantly raise per-site development costs and create a competitive disadvantage compared with nearby municipalities.

Board members pressed staff on technical choices, schedules and fairness. Director Computers said he spent Sunday listening to the development community and local residents and warned the debate could be a “bloodbath” at the next meeting; he pressed staff to explain why small, single-lot projects in older neighborhoods would be excluded even though they contribute to impermeability. Director Ward asked whether recent stakeholder requests — including keeping the existing rational method and removing certain minimum-standard language — could be fulfilled in the manual. Staff replied they had discussed adding language that the manual would not be less stringent than state requirements and that specific developer obligations could be spelled out in the city’s SWIP (stormwater pollution prevention plan) section.

On methodology, staff defended moving away from older engineering approaches. “The methodologies that are currently in use under predict the amount of stormwater runoff volume. So we’re undersizing our detention ponds,” a staff scientist said, and staff said they raised the threshold for using the modified rational method from 20 acres to 40 acres to reduce developer impacts while improving reliability. Staff also said some neighboring jurisdictions already require different methods; for example, some do not allow the modified rational method at all.

On enforcement and schedule, Brad told the board ADEQ has shown little flexibility. “We asked them today about the phasing in of the water quality, and they said that is an absolute no,” he reported. He also told directors: “We could be fined $10,000 a day” if the city misses permit obligations.

Directors asked staff to confirm whether ADEQ applies the same standards to Little Rock as to other cities and whether any equity or phasing options exist; staff committed to follow up with ADEQ and the city attorney and to supply requested comparisons. Several directors asked for an additional stakeholder meeting as soon as possible to let development and neighborhood representatives present concerns together before a final vote.

Next steps: staff said they will work with the city attorney to address grandfathering and ordinance language and will bring material back to the board quickly so the city can submit the MS4 documentation to ADEQ by the March 31 deadline.