Savannah is home to about 24 major drainage basins, and the city has conducted flood modeling for 10 of them.
The 14 in need of that foundational study have been faced with a $2.1 million funding gap in recent years--until now.
The City of Savannah announced last week new federal and state grantmoney for its stormwater master planning, funding that will complete flood modeling across all 24 of its drainage basins. City stormwater staff says that study of hydraulic conditions and needed improvements serves as the backbone for its entire drainage program.
“The information (the models) give is just critical to our operations,” said Savannah’s Senior Director of Stormwater Management Zack Hoffman. "... it really drives our entire program. We find ourselves
continuously reviewing back to these models."
The city’s new modeling and master planning efforts will cost $2.5 million, according to the city’s original announcement of the grants. $1.9 million of that funding came through a federal Hazard Mitigation Grant Program award with an additional $259,155 from the Georgia Management Agency.
The city is providing a $388,733 match for the grant. Previously, the city funded its modeling through the general fund. But vying for money in that fund is often competitive against priorities from other city departments, Hoffman said.
That's why grant funding is a critical leg in the city’s blueprint for funding drainage needs. The grant funds are utilized alongside other funding sources such as Special Purpose Local Option Sales Tax revenues, general fund dollars and the new stormwater utility fee, department leaders say.
“Having these multiple funding sources blended together is what gives us the opportunity to fund the entire program as we’ve conceived it,” said Savannah’s Chief of Water Resources Ron Feldner.
The modern modeling being undertaken by the city can glean insights into how its stormwater system will react to various scales of rain events, highlighting where flood issues could arise based on a given amount of rainfall. But city staff can also ask the model for proposed improvements based on certain rainfall such levels as the 100-year storm event, which Feldner said is equivalent to about 12 inches of rain in 24 hours.
Proposed improvements suggested by the model can include details as specific as the size of pipe needed to eliminate street flooding in specific areas.
The 14 not-yet-modeled basins are also in critical areas—generally in the southern and western portions of the city. Hoffman noted those regions are some of the fastest growing in Savannah and targets of new development. New modeling can be used to inform permitting and assess the drainage impacts or needs of new development, something critical to those high-growth areas.
“Having these models to help us manage and permit (that development) appropriately is critical,” Hoffman said.
But another reason the models are so foundational to staff is that they inform every aspect of the system. Beyond just permit reviews and identifying problem areas, the models can also help prioritize capital projects.
Feldner said having the models for prioritization is key. The city’s stormwater utility ordinance, which instituted the new stormwater utility fee, includes a community equity provision that requires the most flood-risk areas be addressed accordingly.
The provision was requested by neighborhood leaders during a focus group during the stormwater utility’s public engagement phase. Feldner said the residents specifically requested a system for the city to prioritize projects.
The models will be a key element of that system while also ensuring the city utilizes its funding strategically.
“We’ll never have enough money to do everything so therefore the money that we have available to us, we have to prioritize,” Feldner said.
Evan Lasseter is the City of Savannah and Chatham County government reporter for the Savannah Morning News. You can reach him at ELasseter@savannahnow.com.
This article originally appeared on Savannah Morning News: Savannah to propel "critical" flood modeling with new funding
