And Flood Resilient Design in Austin, Texas

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1 And Flood Resilient Design in Austin, Texas

2 The good, the bad and the ugly; What does this video show us?

3 Riverine Flooding versus Flash Flooding

4 Flash Flood Alley Stretches along the I 35 corridor between San Antonio and Dallas

5 Topography of Flash Flood Alley Hilly terrain First substantial increase in elevation from Gulf of Mexico Thin topsoil Rocky strata

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7 Review of Concepts Related to Risk 100 Year Floodplain an area having a 1 percent or greater chance of flooding within any given year FEMA refers to the 100 year floodplain as the Special Flood Hazard Area or SFHA Base Flood refers to a 100 year flood event and the Base Flood Elevation is the elevation above sea level to which flood waters are expected to rise during a 100 year flood event

8 Review of Concepts Related to Risk Freeboard the floodplain management concept of requiring that the finished floor of a building being elevated a specified difference above the Base Flood Elevation Lowest Adjacent Grade the lowest elevation of the ground directly adjacent to a building, either next to the foundation or pier

9 Different Types of Risk While homes within the 100 year floodplain (SFHA) have at least a 1 percent change of flooding annually, the risk of flooding becomes at least 26 percent over the course of a 30 year mortgage. Comparatively, a home has only a 7 percent chance of having a fire during the course of a 30 year mortgage.

10 History of the NFIP Established 1968, the NFIP offers subsidized flood insurance to all residents in participating communities. A community must participate in the NFIP in order to be eligible for federal disaster assistance. In Texas, the NFIP is administered by the Water Development Board, located in Austin. They are tasked with ensuring communities follow the requirements of the program. Homeowners with federally backed loans on homes in the mapped floodplain are required to carry a flood insurance policy. Without the NFIP, homeowners may not be able to purchase or afford flood insurance and thus may not be able to secure loans.

11 History of the NFIP Austin was granted full entry to the NFIP in 1981 There are over 5,700 NFIP policies currently in Austin Over 1.25 billion dollars of buildings and contents are insured through the NFIP in Austin Since Austin joined the NFIP there have been 1,718 claims with 42 million dollars in losses paid The average flood insurance premium in Austin is $727 annually

12 How the NFIP Works

13 What are the Floodplain Rules of the Land Development Code Parts (A) and (B) Prohibit new buildings and parking in the 25 and 100 year floodplains. A building is in the floodplain if the Lowest Adjacent Grade is below the Base Flood Elevation. Parking is considered in the floodplain if water of any depth would be expected during a 100 year flood event.

14 What are the Floodplain Rules of the Land Development Code Part (C) Grants the director of Watershed Protection the authority to issue a variance to parts (A) and (B) if The proposed building has 2 feet of freeboard The proposed building has safe access The proposed building is structurally designed to withstand the force of flood waters The proposed development compensates for any loss of floodplain storage The proposed development improves the local drainage system The variance is required by unique site conditions The proposed development does not cause additional adverse flooding on other properties

15 Understanding (C) Safe Access is the ability for occupants in the building, or first responders going to building, to travel between the building and the right of way while being located at least one foot above the 100 year floodplain elevation at all times.

16 What are the Floodplain Rules of the Land Development Code Specifies 4 types of development which may encroach in the 100 year but not 25 year floodplain provided the development complies with the flood proofing requirements of the building code and does not cause an adverse impact to the floodplain A new parking area less than 5,000 sq. ft. or an unoccupied building less than 1,000 sq. ft. A new single family or duplex structure in a subdivision recorded prior to September 25 th, 1983 and in which only one residential structure is built on a platted lot. A building authorized by a waterway development permit issued prior to September 25 th, 1983 A building in the 100 year floodplain of Lady Bird Lake or the Colorado River downstream of Longhorn Dam.

17 Resources partment/floodplainmanagement andregulations

18 Contact Info Jameson Courtney 505 Barton Springs Rd 12th Floor Austin, TX (512)