MCD dams, levees, and other parts of the flood protection system have worked harder and stored more water in recent decades. This results in stress on the system. More frequent events add pressure on infrastructure that is aging and in need of repair and renewal. Four major factors are identified that could pose risk to the flood protection system.
#1 Aging Infrastructure
Most of the system is over 100 years old and exposed to the elements of nature. The materials used, like concrete and steel, have finite life spans. Earthen materials, like soil and gravel, can settle, erode, and wash away. Without renewed and sustained investment, these materials will continue to deteriorate.
Science and engineering of dams and levees have advanced since MCD constructed its system and implemented its Dam Safety Initiative capital improvements program in 1999.
#2 Weather Trends
Increasing precipitation trends are adding stress to the system and contributing to more loading on the earthen structures. The change in average precipitation in the Great Miami River Watershed has steadily increased, especially since the 1980s.
The annual average number of storage events throughout the system's history is 20, but the trend is increasing. The average over the last 30 years has increased to 28. More frequent high-water events mean the dam and levee soils are saturated more often and exposed to more frequent erosive forces.
Similarly, the other flood protection infrastructure like floodwalls, pipes, and floodgates are exposed to storm water more frequently. This will lead to more frequent maintenance needs and capital projects, including additional slope armoring.
#3 Expiration of the Dam Safety Initiative
With the expiration of the Dam Safety Initiative’s (DSI) capital assessment in 2022, MCD has no sustained funding for necessary capital improvements needed to ensure long term protection. Additionally, the DSI assessment limited uses that did not allow for rehabilitation or replacement of levees.
#4 Assessment Revenues Flat Since 2012
From 2012-2022, MCD had a maintenance assessment and a capital assessment. During this time, the assessment rates did not increase, and assessment revenues remained flat.
In 2023, MCD’s annual flood protection maintenance assessment revenues are projected at about $6.4 million.
Approved by the Conservancy Court, this is based on a “no net change” to increase the maintenance assessment by the same amount as the reduction from the expiring DSI assessment. Even with this additional $1.6M, MCD’s non-capital maintenance expenses are projected to be $9.9 million in 2025.
A forecasted deficit of $3.5M is related to the assessment revenues remaining flat since 2012, while expenditures increased.
At the end of 2022, the maintenance fund had an unencumbered balance of $8.4 million. This will be completely depleted within the next couple of years if additional revenues are not collected.
