14 C20-2022-025 - Colorado River Protections Staff Report — original pdf

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12/04/24 C20-2022-025 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 and bounded by public rights-of-way and only affecting new habitable structures and subsurface infrastructure. See Attachment A. Summary of proposed code changes: The proposed code change would expand the Erosion Hazard Zone (EHZ) associated with the Colorado River downstream of the Longhorn Dam to 200 feet from the ordinary high-water mark (federally defined edge of river bank). The existing EHZ is measured 100 feet from the ordinary high-water mark. The EHZ would only apply to new habitable structures (e.g., residential houses) and infrastructure (e.g., new roadways, water and wastewater pipes) and NOT to existing structures and infrastructure or to new sheds, pools, patios, decks, fences, and the like. Staff are proposing that EHZ requirements for hard-surfaced trails remain at 100 feet. The EHZ would also not extend past existing public rights-of-way. Thus, for example, a property on the far side of a public roadway from river would not be subject to the EHZ. Additionally, single-family residential construction in the Extra Territorial Jurisdiction would not be affected by this ordinance since Travis County, not the City of Austin, regulates such construction. After presenting the proposed ordinance to the Austin Contractors and Engineers Association, one suggestion that resulted from that discussion is to amend the code to allow for an administrative variance to LDC 25-8-341 to allow for cut and fill greater than four feet as minimally necessary to allow for grading resulting from protective works. Staff are in support of this additional code change. However, this additional code change would require additional public notice. 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.” 1 12/04/24 C20-2022-025 Board and Commission Actions: October 16, 2024: Codes and Ordinances Joint Committee supported the staff recommendation on a vote of 6-0 with the following two amendments: 1. Recommend staff create a map for public consumption before October 28th. 2. Recommend the creation of an administrative variance to the Erosion Hazard Zone requirements at the time of building permit if there is a roadway or other structure between the development and the origin point of the buffer. November 6, 2024: Environmental Commission supported the staff recommendation on a vote of 7-0 with the following three amendments: 1. Create data and map of a geological analysis for soil types and erosion rates. 2. Increase the erosion hazard zone from 200 ft to 400ft. 3. Clarify how projects that require site plans and applicable permits will be included in the code. December 10, 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: Staff request a postponement to January 30, 2025. January 30, 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 2 12/04/24 C20-2022-025 Attachment A: Proposed Code Language § 25-7-32 EROSION HAZARD ZONE ANALYSIS REQUIREMENT. (A) 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. (B) An erosion hazard analysis is not required for: a minor, non-habitable residential appurtenance to a residential use; (1) (2) a hard-surfaced trail located between 100 and 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 (3) development on a property separated from the triggering waterway by a public roadway. (C)(B) 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 (3) located where significant erosion is present. (D)(C) The erosion hazard zone analysis must be in accordance with the Drainage Criteria Manual. (E)(D) 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. 3 Affordability Impact Statement Colorado River Protection Ordinance Case number: C20-2022-025 Initiated by: Resolution No. 20220609-061 Date: 12/2/2024 Proposed Regulation The current Land Development Code’s Drainage Chapter mandates a 100-foot Erosion Hazard Zone (EHZ) along the Colorado River downstream of Lady Bird Lake. Due to the river’s bank heights and erosive force, this distance is insufficient for protecting buildings and infrastructure. The proposed ordinance seeks to expand the EHZ from 100 feet to 200 feet for new buildings and infrastructure. This expansion excludes hard-surfaced trails, which will retain the 100-foot requirement. Additionally, the proposed Drainage Criteria Manual (DCM) rules introduce standards for non-erosive stormwater outfalls in high-erosion areas, particularly where sandy soils are prevalent. Land Use/Zoning Impacts on Housing Costs The proposed EHZ expansion is anticipated to have a neutral impact on housing costs. Watershed Protection Department (WPD) staff have engaged with various stakeholders, including the Lower Colorado River Authority (LCRA), Travis County, Austin Water (AW), Transportation & Public Works (TPW), Parks & Recreation Department (PARD), Austin Energy (AE), community organization PODER, and developers currently undergoing permitting processes. Development stakeholders noted the 200-foot EHZ aligns with the setback under existing Critical Water Quality Zone buffers, thus minimizing development footprint impacts. Additionally, stakeholders PARD and TPW, along with developers, requested that hard-surfaced trails remain under the 100-foot requirement to prevent excessive costs, maintain the trails’ accessibility, and reduce the need for additional easement acquisitions. Impact on Development Cost The proposed changes would have minimal impacts on development cost. Financial impacts will vary by project type and whether a project is new or a redevelopment. Parcels affected by this provision are limited to those along the 25.2 miles of Colorado River downstream of Lady Bird Lake, totaling under 360 parcels. This regulation would not apply to single-family construction in the ETJ, which accounts for 70 of the 360 parcels. For new subdivisions and site plans, the impact is minimal due to the existing minimum 200-foot buffer already restricting most development. Redevelopment site plans and single-family permits, however, could face increased foundation construction costs if building within the EHZ. Structural engineers have estimated potential cost increases of 3-5 times for foundations requiring deeper subsurface anchoring and additional protections against erosion. Developers may opt to relocate structures outside the EHZ to avoid these additional costs. Although developments may increase foundation and erosion protection costs for structures in the EHZ, these costs are expected to be offset by reduced maintenance expenses. Without this ordinance, buildings constructed without protective measures would face greater risks of erosion-related damage, potentially resulting in costly public buyouts or repair expenditures. Impact on Affordable Housing The proposed changes would have a neutral impact on affordable housing. The effects on household affordability are expected to be limited due to several factors: 1. The regulation impacts less than 360 parcels. 2. Currently, there are no multifamily residences within the proposed EHZ. Existing residential properties are predominantly single-family units with limited affordable housing potential and this regulation does not apply to single-family residential construction in the ETJ. 3. Future multifamily projects would still be required to adhere to the 200-foot setback requirement already in place, thus the new 200ft EHZ would have no more restrictive effect. In weighing the short-term costs of increased erosion protection measures against the potential long-term costs of erosion damage and buyouts, the ordinance is anticipated to preserve infrastructure and minimize future public costs. Other Policy Considerations The proposed ordinance aligns with the Watershed Protection Strategic Plan’s goals to strengthen erosion control, protect public and private assets, and maintain stable stream systems. Key objectives include preventing property damage and minimizing channel enlargement that threatens property. Austin’s Climate Equity Plan notes that “East Austin has taken on much of the burden of the city’s growth and development” and that “displacement and reduced mobility due to flooding and extreme weather are disproportionality faced by marginalized communities.” Expanding erosion protection along the Colorado River preserves the natural landscape, shields residents from environmental hazards, and supports equitable environmental stewardship, fostering long-term livability. Watershed Protection has taken a measured approach with this EHZ expansion, balancing development needs with enhanced erosion protections. This balanced approach can serve as a guiding framework for future updates to regulations in various areas, focusing on maintaining essential protections while supporting sustainable growth. Manager’s Signature ___ ___________________________________