We are in the process of changing our floodplain regulations in light of the National Weather Service study of historical rainfall called Atlas 14. It shows that large storms are more likely than previously realized.
Austin regulates new development, redevelopment and remodeling in the floodplain. These regulations are meant to protect Austinites from flooding and reduce public expense in the aftermath of a flood. We have started the process to change these regulations.
Austin also requires developers to include drainage pipes, detention ponds and/or other drainage infrastructure in their projects. The drainage criteria tell developers the proper size their drainage infrastructure needs to be. We will be changing the drainage criteria in a separate process.
It uses an interim 100-year floodplain, based on the current 500-year floodplain, to regulate development. This change means that the floodplain regulations will apply to more properties. Property owners and businesses in the interim 100-year floodplain would have new restrictions if they want to develop, expand, remodel or improve their properties. We estimate that there are approximately 7,200 buildings in the interim 100-year floodplain.
It includes a new exception that will allow for the administrative approval for redevelopment of a residential building in the floodplain that reduces flood risk. Currently, this often requires approval by the Austin City Council.
It proposes to expand an existing exception that allows for a building to encroach on the 100-year floodplain of the Colorado River downstream of Longhorn Dam and along Lady Bird Lake to also include Lake Austin and parts of Lake Travis.
It proposes an increase in the freeboard requirement for buildings from 1 foot to 2 feet.
Since July 2018, Watershed Protection has held or attended more than 88 meetings to gather input from various stakeholder groups and the public. Additional opportunities for public input will be available through the process of public hearings. Following all public hearings, the Austin City Council will consider adopting the proposed regulations. The tentative schedule for public hearings about the proposed regulations is as follows: