§ 30-5-261. 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 director, subject to the conditions in this Subsection.

(1)

In a water supply rural watershed, water supply suburban watershed, 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 master planned park that is approved by the council 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 30-5-262 ( Critical Water Quality Zone Street 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)

located outside the erosion hazard zone unless protective works are provided as prescribed in the Drainage Criteria Manual;

(c)

limited to 12 feet in width unless a wider trail is designated in the Urban Trails Master Plan adopted by Council;

(d)

located not less than 25 feet from the centerline of a waterway if within an urban watershed;

(e)

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;

(f)

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 30-5-92; and

(g)

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:

(a)

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;

(b)

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 30-5-92;

(c)

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

(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)

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;

(b)

located not less than 50 feet from the shoreline of Lady Bird Lake and Lake Walter E. Long, as defined in Section 30-5-92;

(c)

located not less than 100 feet from the ordinary high water mark of the Colorado River downstream from Longhorn Dam; and

(d)

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, or 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)

Approval by the Watershed Protection Department director of chemicals used to treat building materials that will be submerged in water is required before a permit may be issued or a site plan released.

(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.

(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:

(1)

the utility line follows the most direct path into or across the critical water quality zone to minimize disturbance;

(2)

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; and

(3)

in the Barton Springs Zone, is approved the Watershed Protection Department director.

(E)

In the urban and suburban watersheds, a utility line may be located parallel to and within the critical water quality zone if:

(1)

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;

(2)

located not less than 50 feet from the shoreline of Lady Bird Lake and Lake Walter E. Long, as defined in Section 30-5-92;

(3)

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

(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 designed in accordance with the Environmental Criteria Manual.

(G)

Floodplain modifications are prohibited in the critical water quality zone unless:

(1)

the floodplain modifications proposed are necessary to address an existing threat to public health and safety, as determined by the Watershed Protection Department director;

(2)

the floodplain modifications proposed would provide a significant, demonstrable environmental benefit, as determined by a functional assessment of floodplain health as prescribed by the Environmental Criteria Manual; or

(3)

the floodplain modifications proposed are necessary for development allowed in the critical water quality zone under Section 30-5-261 ( Critical Water Quality Zone Development ), 30-5-262 ( Critical Water Quality Zone Street Crossings ), or Section 25-8-367 ( Restrictions on Development Impacting Lake Austin, Lady Bird Lake, and Lake Walter E. Long ).

(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:

(1)

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;

(2)

located not less than 50 feet from the shoreline of Lady Bird Lake and Lake Walter E. Long, as defined in Section 30-5-92;

(3)

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.

(I)

Development associated with power generation, transmission, or distribution at the Decker Creek Power Station is allowed in the critical water quality zone.

(J)

A residential lot that is 5,750 square feet or less in size may not include any portion of a critical water quality zone.

Source: City Code Section 25-8-261; Ord. 031211-11; Ord. 031211-42; Ord. 20131017-046; Ord. No. 20160922-048 , Pt. 8; Ord. No. 20170615-102 , Pt. 44, 6-15-17.