The city of Greenville’s flood plain map is all about risk.
What is the risk of flooding in my neighborhood? What is the risk of damage to my property if a flood occurs? These types of questions are best answered when there is an accurate map depicting which areas in the city are subject to flooding.
Revisions have been proposed to improve the accuracy and consistency of the city’s current flood plain map. The changes are part of the city’s six-month review of the development code.
New updates to the regulatory flood plain map come from a citywide flood study completed in June 2019 as part of the city’s Stormwater 2.0 initiative. Before the study, the map consisted of information collected from 14 smaller area flood studies completed over more than 20 years.
“Now, we have an identical application and flood plain mapping throughout the city,” said Paul Dow, a city engineer.
Land parcels were both removed and added to the new map. However, the overall amount of land within the flood plain was reduced, according to the city.
What’s the impact?
Properties located within the city’s flood plain require certain building flood protections. Developers constructing new buildings must follow these requirements outlined in the city’s development code. Due to the additional requirements, it can be more costly to build within a flood plain.
Dow said there are no retroactions for existing buildings added to the flood plain. However, if substantial improvements adding more than 50% of that building’s value are completed to the existing structure, the building protection requirements will apply.
Properties removed from the flood plain will no longer be subject to the city’s flood requirements. More properties than before will have fewer requirements since the city’s overall flood plain was reduced, Dow explained.
It’s important to note that the city’s updated flood plain map will not impact a property owner’s flood insurance. Instead, flood insurance is based on the flood plain maps created by the Federal Emergency Management Agency (FEMA). Dow said the city’s new flood plain map will not be submitted for FEMA to update its map.
“We encourage people to get flood insurance and if you’re outside of a flood zone – a FEMA flood zone – your flood insurance is drastically cheaper,” Dow said.
Using the new flood plain map, the city has prioritized a list of new stormwater projects to complete.
“We have a prioritization of what’s called level of service. Level of services is just a word that means how well a culvert or a pipe can handle a certain storm,” Dow said. “So we now have a list from this model of pipes to focus on.”
The updated flood plain map will be presented to the city’s Planning Commission Feb. 13 as part of the development code’s six-month review. Greenville City Council will then review and vote on the updates.
Dow believes the flood plain map should be reviewed again in five years. With the new comprehensive, citywide map, city engineers will be able to easily update the map in the future
“We don’t have to pick it up from various places anymore,” Dow said. “We have an established baseline model that can get updated as rainfall amounts are collected.”