MSD engineering: extreme, short-duration storms overwhelmed system; full fixes could cost billions

Reese Johnson, MSD chief engineer, presented engineering analysis showing the recent storms were characterized by very steep rainfall accumulation curves—large amounts of rain in very short intervals—which exceeds what sewer systems are designed to convey.

"The storms we've received over the last two weeks are extreme, and their intensity, more than just their total depth, is what has overwhelmed the MSD sewer system," Johnson said, explaining that the system was "overwhelmed" rather than operationally failed.

Johnson described past engineering work: an East Side study that concluded a comprehensive solution for certain East Side basins (to the 10-year design standard) could cost roughly $2.4 billion (in 2022 dollars). Recognizing that figure s impractical to implement at once, MSD has commissioned a countywide SBU study and a fast-track urgent-capacity project study that identified 10 projects; one is already in the 2026 capital-improvement program and others will be nominated for future CIP cycles.

Johnson and MSD emphasized a mix of approaches going forward: targeted capital projects focused on SBU clusters, incentives or requirements for more private-property stormwater detention, and research partnerships (including University of Cincinnati) to better understand the patterns that produce recurring, high-intensity pop-up storms in certain neighborhoods.

Commissioners and staff discussed tradeoffs: whether to pursue large capital builds, prioritize smaller fast-track projects, and how to coordinate across dozens of municipal and regional agencies that share stormwater responsibilities.