GENERAL PROVISIONS.

Austin City Code tit. 30, ch. 30-4, art. 1

in effect

Austin City Code § 30-4-1 DEFINITIONS.

§ 30-4-1 - DEFINITIONS. In this chapter: (1) ADVERSE FLOODING IMPACT means an increase in flood risk or hazards. (2) DEVELOPMENT APPLICATION means an application required under Title 25 for development, such as an application for subdivision, site plan, or building permit. (3) DIRECTOR, when used without a qualifier, means the director of the Watershed Protection Department, or the director's designee. (4) DRAINAGE EASEMENT means an easement or right-of-way for a drainage facility required by Section 25-7-152 (Dedication of Easements and Rights-of-Way). (5) EROSION HAZARD ZONE means an area where future stream channel erosion is predicted to result in damage to or loss of property, buildings, infrastructure, utilities, or other valued resources. (6) FEMA means the Federal Emergency Management Agency. (7) FEMA FLOODPLAIN means a special flood hazard area delineated on a flood insurance rate map. (8) FLOOD INSURANCE RATE MAP means an official map of a community on which FEMA has delineated both the areas of special flood hazards and the risk premium zones applicable to the community. (9) ATLAS 14 means the National Oceanic and Atmospheric Administration's Precipitation-Frequency Atlas 14 of the United States, Volume 11, Version 2.0: Texas. (10) 100-YEAR FLOODPLAIN means an area within a floodplain subject to a one percent or greater chance of flooding in any year as calculated in accordance with Section 30-4-5 (Determination of the 100-Year Floodplain). (11) 25-YEAR FLOODPLAIN means an area within a floodplain subject to a four percent or greater chance of flooding in any year as calculated in accordance with Section 30-4-6 (Determination of the 25-Year Floodplain). (12) WATERWAY means a watercourse, drainage way, branch, creek, or stream including, but not limited to, the limits of the 100-year and 25-year floodplains. Source: Ord. 20131017-046; Ord. No. 20191114-064, Pts. 27, 28, 11-25-19.

Austin City Code § 30-4-2 OBSTRUCTION OF WATERWAYS PROHIBITED.

§ 30-4-2 - OBSTRUCTION OF WATERWAYS PROHIBITED. Unless authorized by a subdivision construction plan approved under County Code Chapter 64 (Regulations for Flood Management and Guidelines for Development Permits), or a development application approved under City Code Title 25, a person may not place, or cause to be placed, an obstruction in a waterway. Source: Ord. 20131017-046.

Austin City Code § 30-4-3 DUTY TO MAINTAIN UNOBSTRUCTED WATERWAYS.

§ 30-4-3 - DUTY TO MAINTAIN UNOBSTRUCTED WATERWAYS. The person in control of real property traversed by a waterway shall keep the waterway free from an obstruction that is not authorized by a development application approved under Title 25 or County Code Chapter 64. Source: Ord. 20131017-046.

Austin City Code § 30-4-4 STANDING WATER DECLARED A NUISANCE.

§ 30-4-4 - STANDING WATER DECLARED A NUISANCE. A pool of standing water in a waterway that is caused by an unauthorized obstruction in the waterway is declared to be a nuisance. Source: Ord. 20131017-046.

Austin City Code § 30-4-5 DETERMINATION OF THE 100-YEAR FLOODPLAIN.

§ 30-4-5 - DETERMINATION OF THE 100-YEAR FLOODPLAIN. For purposes of this chapter, the 100-year floodplain shall be: (A) For areas amended to incorporate Atlas 14 data, the 100-year floodplain calculated under fully developed conditions as prescribed by the Drainage Criteria Manual as amended to incorporate Atlas 14 data; (B) For areas not yet amended to incorporate Atlas 14 data, the 500-year floodplain either as depicted on the FEMA Flood Insurance Rate Map as of January 6, 2016, as subsequently revised, or as calculated under existing conditions as prescribed by the Drainage Criteria Manual using data predating Atlas 14; or (C) For the Colorado River, the 100-year floodplain as depicted on the FEMA Flood Insurance Rate Map dates January 6, 2016, or as subsequently revised. Source: Ord. No. 20191114-064, Pt. 30, 11-25-19.

Austin City Code § 30-4-6 DETERMINATION OF THE 25-YEAR FLOODPLAIN.

§ 30-4-6 - DETERMINATION OF THE 25-YEAR FLOODPLAIN. For purposes of this chapter, the 25-year floodplain shall be: (A) For areas amended to incorporate Atlas 14 data, the 25-year floodplain calculated under fully developed conditions as prescribed by the Drainage Criteria Manual as amended to incorporate Atlas 14 data; (B) For area not yet amended to consider Atlas 14 data, the 100-year floodplain calculated under fully developed conditions as prescribed by the Drainage Criteria Manual using data predating Atlas 14; or (C) For the Colorado River, the 25-year floodplain as calculated under existing conditions as prescribed by the Drainage Criteria Manual using data predating Atlas 14. Source: Ord. No. 20191114-064, Pt. 30, 11-25-19.

Austin City Code § 30-4-7 COMPUTATION OF STORMWATER RUNOFF.

§ 30-4-7 - COMPUTATION OF STORMWATER RUNOFF. (A) Except as provided in Subsection (B), stormwater runoff shall be computed on the basis of a fully developed contributing drainage area or watershed as determined under the Drainage Criteria Manual. (B) When determining the runoff generated from the 500-year flood for the purpose of determining the 100-year floodplain under Subsection (B) of Section 30-4-5 (Determination of the 100-Year Floodplain), stormwater runoff shall be computed on the basis of an existing developed contributing drainage area or watershed. Source: Ord. 20131017-046; Ord. No. 20191114-064, Pt. 29, 11-25-19.

Source: City of Austin, City Code and City Charter (Municode Library, library.municode.com)URL: https://library.municode.com/tx/austin/codes/code_of_ordinances?nodeId=TIT30AUTRCOSURE_CH30-4DR_ART1GEPRFetched: 10/27/2026