30 C20-2023-013 - Butler Trail Amendments Draft Ordinance — original pdf

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§ 25-8-261 CRITICAL WATER QUALITY ZONE DEVELOPMENT. In all watersheds, development is prohibited in a critical water quality zone except as provided in this Division. Development allowed in the critical water quality zone under this Division shall be revegetated and restored within the limits of construction as prescribed by the Environmental Criteria Manual. (A) A fence that does not obstruct flood flows is permitted in a critical water quality zone. (B) Open space is permitted in a critical water quality zone if a program of fertilizer, pesticide, and herbicide use is approved by the Watershed Protection Department, subject to the conditions in this Subsection. (1) In a water supply rural watershed, water supply suburban, or the Barton Springs Zone, open space is limited to sustainable urban agriculture or a community garden if the requirements in Subsection (B)(4) are met, multi-use trails, picnic facilities, and outdoor facilities, excluding stables, corrals for animals and athletic fields. (2) A park with a council-adopted plan may include recreational development other than that described in Subsection (B)(1). (3) A hard surfaced trail may cross the critical water quality zone pursuant to Section 25-8-262 (Critical Water Quality Zone Mobility Crossings). A hard surfaced trail that does not cross the critical water quality zone may be located within the critical water quality zone only if: (a) designed in accordance with the Environmental Criteria Manual; (b) (c) (d) (e) (f) (g) (a) (b) (c) located outside the erosion hazard zone unless protective works are provided as prescribed in the Drainage Criteria Manual; limited to 12 feet in width plus one-foot compacted sub-grade shoulders, unless a wider trail is designated in a Council-adopted plan; located not less than 25 feet from the centerline of a waterway if within an urban watershed; located not less than 50 feet from the centerline of a minor waterway, 100 feet from the centerline of an intermediate waterway, and 150 feet from the centerline of a major waterway if within a watershed other than an urban watershed; located not less than 50 feet from the shoreline of Lake Travis, Lake Austin, Lady Bird Lake, and Lake Walter E. Long, as defined in Section 25-8-92; and located not less than 100 feet from the ordinary high water mark of the Colorado River downstream from Longhorn Dam. (4) Open space may include sustainable urban agriculture or a community garden only if: in an urban watershed and located not less than 25 feet from the centerline of a waterway, or in a watershed other than an urban watershed and located not less than 50 feet from the centerline of a minor waterway, 100 feet from the centerline of an intermediate waterway, and 150 feet from the centerline of a major waterway; located not less than 50 feet from the shoreline of Lake Travis, Lake Austin, Lady Bird Lake, and Lake Walter E. Long, as defined in Section 25-8-92; located not less than 100 feet from the ordinary high water mark of the Colorado River downstream from Longhorn Dam; (d) designed in accordance with the Environmental Criteria Manual; and (Supp. No. 163) Created: 2023-11-22 15:19:12 [EST] Page 1 of 5 (e) limited to garden plots and paths, with no storage facilities or other structures over 500 square feet. (5) In a suburban or urban watershed, open space may include an athletic field only if: (a) (b) (c) (d) in an urban watershed and located not less than 25 feet from the centerline of a waterway, or in a suburban watershed and located not less than 50 feet from the centerline of a minor waterway, 100 feet from the centerline of an intermediate waterway, and 150 feet from the centerline of a major waterway; located not less than 50 feet from the shoreline of Lady Bird Lake and Lake Walter E. Long, as defined in Section 25-8-92; located not less than 100 feet from the ordinary high water mark of the Colorado River downstream from Longhorn Dam; and the owner of the athletic field submits to the Watershed Protection Department a maintenance plan to keep the athletic field well vegetated and minimize compaction, as prescribed in the Environmental Criteria Manual. (C) The requirements of this subsection apply along Lake Travis, Lake Austin, Lake Walter E. Long, and Lady Bird Lake. (1) A dock, public boat ramp, bulkhead or marina, and necessary access and appurtenances, are permitted in a critical water quality zone subject to compliance with Chapter 25-2, Subchapter C, Article 12 (Docks, Bulkheads, and Shoreline Access). For a single-family residential use, necessary access may not exceed the minimum area of land disturbance required to construct a single means of access from the shoreline to a dock. (2) Disturbed areas must be restored in accordance with the Environmental Criteria Manual and the following requirements: (a) Within a lakefront critical water quality zone, or an equivalent area within 25 feet of a shoreline, restoration must include: (i) at least one native shade tree and one native understory tree, per 500 square feet of disturbed area; and (ii) one native shrub per 150 square feet of disturbed area; and (b) Remaining disturbed areas must be restored per standard specifications for native restoration. (3) Within the shoreline setback area defined by Section 25-2-551 (Lake Austin (LA) District Regulations) and within the overlay established by Section 25-2-180 (Lake Austin (LA) Overlay District), no more than 30 percent of the total number of shade trees of 8 inches or greater, as designated in the Environmental Criteria Manual, may be removed. (4) Before a building permit may be issued or a site plan released, approval by the Watershed Protection Department is required for chemicals used to treat building materials that will be submerged in water. (5) Bank erosion above the 100-year-flood plain may be stabilized within a lakefront critical water quality zone if the restoration meets the requirements of Subsection (B)(2) of this section. (6) A retaining wall, bulkhead, or other erosion protection device must be designed and constructed to minimize wave return and wave action in compliance with the Environmental Criteria Manual. A shoreline modification within the wave action zone with a greater than 45 degree vertical slope (Supp. No. 163) Created: 2023-11-22 15:19:12 [EST] Page 2 of 5 for any portion greater than one foot in height is not allowed on or adjacent to the shoreline of a lake, unless the shoreline modification is located within an existing man-made channel. (7) A retaining wall, bulkhead, or other erosion protection device may not capture or recapture land from a lake unless doing so is required to restore the shoreline to whichever of the following boundaries would encroach the least into the lake: (a) the shoreline as it existed 10 years before the date of application, with documentation as prescribed by the Environmental Criteria Manual; or (b) the lakeside boundary of the subdivided lot line. (8) A bulkhead may be replaced in front of an existing bulkhead once, if: (a) the existing bulkhead was legally constructed; (b) (c) construction of the replacement bulkhead does not change the location of the shoreline by more than 6 inches; and the director determines that there is no reasonable alternative to replacement of the bulkhead in the location of the existing bulkhead. (9) Dredging is prohibited unless: (a) the area of dredging is less than 25 cubic yards; and (b) the dredging is necessary for navigation safety. (1) (2) (1) (2) (3) (D) A utility line, including a storm drain, is prohibited in the critical water quality zone, except as provided in Subsection (E) or for a necessary crossing. A necessary utility crossing may cross into or through a critical water quality zone only if: the utility line follows the most direct path into or across the critical water quality zone to minimize disturbance, unless boring or tunneling is the proposed method of installation for the entire crossing and all bore pits are located outside of the critical water quality zone; the depth of the utility line and location of associated access shafts are not located within an erosion hazard zone, unless protective works are provided as prescribed in the Drainage Criteria Manual; (3) in the Barton Springs Zone, the crossing is approved by the director. (E) In the urban and suburban watersheds, a utility line may be located parallel to and within the critical water quality zone if: in an urban watershed and located not less than 50 feet from the centerline of a waterway, or in a watershed other than urban and located not less than 50 feet from the centerline of a minor waterway, 100 feet from the centerline of an intermediate waterway, and 150 feet from the centerline of a major waterway; located not less than 50 feet from the shoreline of Lady Bird Lake and Lake Walter E. Long, as defined in Section 25-8-92; located not less than 100 feet from the ordinary high water mark of the Colorado River downstream from Longhorn Dam; (4) designed in accordance with the Environmental Criteria Manual; (5) located outside the erosion hazard zone, unless protective works are provided as prescribed in the Drainage Criteria Manual; and (Supp. No. 163) Created: 2023-11-22 15:19:12 [EST] Page 3 of 5  (6) the project includes either riparian restoration of an area within the critical water quality zone equal in size to the area of disturbance in accordance with the Environmental Criteria Manual, or payment into the Riparian Zone Mitigation Fund of a non-refundable amount established by ordinance. (F) In-channel detention basins and in-channel wet ponds are allowed in the critical water quality zone only if: (1) proposed as part of a public capital improvement project or public private partnership; (2) no alternative location is feasible; and (3) designed in accordance with the Environmental Criteria Manual. (G) Floodplain modification is prohibited in the critical water quality zone unless the modification proposed: is necessary to address an existing threat to public health and safety, as determined by the director; is designed solely to improve floodplain health as determined by a functional assessment of floodplain health as prescribed by the Environmental Criteria Manual; or is the minimum necessary for development allowed in the critical water quality zone under Section 25-8-261 (Critical Water Quality Zone Development) or Section 25-8-262 (Critical Water Quality Zone Mobility Crossings) as prescribed by the Environmental Criteria Manual. (H) In the urban and suburban watersheds, vegetative filter strips, rain gardens, biofiltration ponds, areas used for irrigation or infiltration of stormwater, or other controls as prescribed by rule are allowed in the critical water quality zone if: in an urban watershed and located not less than 50 feet from the centerline of a waterway, or in a watershed other than urban and located no less than 50 feet from the centerline of a minor waterway, no less than 100 feet from the centerline of an intermediate waterway, and no less than 150 feet from the centerline of a major waterway; located not less than 50 feet from the shoreline of Lady Bird Lake and Lake Walter E. Long, as defined in Section 25-8-92; located not less than 100 feet from the ordinary high water mark of the Colorado River downstream from Longhorn Dam; (4) located outside the 100-year floodplain; and (5) located outside the erosion hazard zone, unless protective works are provided as prescribed in the Drainage Criteria Manual. Development associated with power generation, transmission, or distribution at the Decker Creek Power Station is allowed in the critical water quality zone. A residential lot that is 5,750 square feet or less in size may not include any portion of a critical water quality zone. (1) (2) (3) (1) (2) (3) (K) Any segment of trail that is a part of the Ann and Roy Butler Hike and Bike Trail, as defined by the Parks and Recreation Department, is not subject to Paragraph (B)(3)(c) or Subdivision (C)(2) and may be located within 50 feet of Lady Bird Lake as defined in Section 25-8-92 (Critical Water Quality Zones Established) if: Created: 2023-11-22 15:19:12 [EST] Page 4 of 5 (I) (J) (Supp. No. 163)  (1) restoration, as determined by a functional assessment of floodplain health as prescribed by the Environmental Criteria Manual, includes a restored area at a minimum ratio of 1:1 of restored area to disturbed area and a maximum ratio of 2:1 of restored area to disturbed area, or (2) alternative compliance as approved by the director is provided. (Supp. No. 163) Created: 2023-11-22 15:19:12 [EST] Page 5 of 5