Item3_C20-2024-024_ColoradoRiverProtections_StaffReport — original pdf

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10/11/24 C20-2022-0025 ORDINANCE AMENDMENT REVIEW SHEET Amendment: C20-2022-0025, Land Development Code Amendment to Title 25-7 Drainage Description: Consider an ordinance regarding amendments to Title 25 related to adequate protections to the Colorado River downstream of the Longhorn Dam. Proposed Language: To revise 25-7-32(B)(2) to establish the erosion hazard zone of the Colorado River downstream of the Longhorn Dam as 200 feet from the ordinary high water mark, with exceptions for trails. See Attachment A. Summary of proposed code changes: The proposed code change would expand the Erosion Hazard Zone associated with the Colorado River downstream of the Longhorn Dam to 200 feet from the ordinary high-water mark (federally defined river bank). The existing Erosion Hazard Zone is measured 100 feet from the ordinary high-water mark. Staff are proposing exceptions to this requirement for hard-surfaced trails. Background: This ordinance responds to Council Resolution No. 20220609-061, which initiated Land Development Code amendments related to environmental, drainage, and landscape requirements. A previous ordinance addressed many of the elements of this resolution, but certain proposed changes were not adopted at the time so that staff could conduct additional analyses and community outreach. The proposed ordinance addresses direction to staff to “evaluate the effectiveness of the existing Critical Water Quality Zone and Erosion Hazard Zone buffers on the Colorado River downstream of the Longhorn dam and to propose protections that will provide adequate protections to the river that will ensure a healthy riparian corridor to stabilize the riverbank and protect property from erosion.” Board and Commission Actions: October 16, 2024: Codes and Ordinances Joint Committee action is pending. November 6, 2024: Environmental Commission action is pending. November 12, 2024: Planning Commission action is pending. Council Action: June 9, 2022: City Council approved Resolution No. 20220609-061, initiating amendments to Title 25 related to environmental, drainage, and landscape requirements. December 12, 2024: City Council action is pending. Ordinance Number: N/A City Staff: Matt Hollon, Regulatory Policy Analyst, Liz Johnston, Interim Environmental Officer, Watershed Protection Department Phone: (512) 974-2238 Email: matt.hollon@austintexas.gov 1 10/11/24 C20-2022-0025 Attachment A: Proposed Code Language § 25-7-32 EROSION HAZARD ZONE ANALYSIS REQUIREMENT. For a preliminary plan or plat application to demonstrate that the development proposed in a preliminary plan or plat application does not create negative erosion impacts, the owner of real property may provide, at the owner's expense, an erosion hazard zone analysis. For all other development applications, the director may require the owner of real property to provide, at the owner's expense and as a condition for development application approval, an analysis to establish the erosion hazard zone if the proposed development is: (1) within 100 feet of the centerline of a waterway with a drainage area of 64 acres or greater; or (2) within 100 200 feet of the ordinary high water mark of the Colorado River downstream from Longhorn Dam, as defined by Code of Federal Regulations Title 33, Section 328.3 (Definitions) or 100 feet of the ordinary high water mark for trails; or (3) located where significant erosion is present. (C) The erosion hazard zone analysis must be in accordance with the Drainage Criteria Manual. If an erosion hazard zone analysis is required under this section, the City may not accept for review a development application for any portion of the proposed development until the director has received the required erosion hazard zone analysis. (A) (B) (D) 2