Austin, TX Watershed Protections
Date: 1980 to 1992
The Lake Austin Watershed Ordinance (LAWO) was adopted permanently in January 1980 and represents the City of Austin's first major attempt to address water quality degradation in the face of increasing urbanization. Key features of the ordinance included: slope based impervious cover limits of up to 30 percent that were eventually raised to a maximum of 80 percent with transfers, a provision for water quality and quantity structural controls when minimum ordinance standards were not met, and a requirement for an erosion / sedimentation control plan prior to subdivision application approval. It should be noted that every ordinance discussed hereafter makes provisions for an erosion / sedimentation control plan. The LAWO did not require stream setbacks or buffer zones. The ordinance did, however, prohibit building sites within the 100-year floodplain of any creek or tributary in the watershed.
The Barton Creek Watershed Ordinance (BCWO) was passed in 1980 and represented a significant departure from the Lake Austin Watershed Ordinance. Key features of the ordinance included: impervious cover limits capped at 35 percent for commercial and multi-family development, and the use of density limits that varied with the location of the development. The BCWO did not require water control structures, nor did it provide a mechanism whereby an applicant could increase impervious cover using alternate methods. This ordinance relied entirely on non-structural water quality controls and introduced stream set back requirements that created five water quality zones with enumerated development restrictions for each one. The ordinance also provided incentives (increased density) for the transfer of development rights that included the conveyance of land in the critical water quality zone, for water quality protection, to the City as parkland.
The Williamson Creek Watershed Ordinance (WCWO) applied to that part of Williamson Creek crossing the recharge zone and was passed in December 1980. The WCWO included a requirement for stormwater treatment, a departure from previous ordinances. Key features of the ordinance included: impervious cover limits for single- and two-family homes of 40 percent, and limits of up to 65 percent for commercial and multi-family developments, the use of stream setbacks based on our present concept of major, intermediate and minor waterways, and the inclusion of a critical water quality zone that was to remain free of all but certain types of development.
The Lower Watersheds Ordinance (LWO) was adopted in 1981 and extended water quality protection into the Slaughter, Bear, Little Bear and Onion Creek watersheds. The LWO resembles the WCWO in many ways, except that it reduces impervious cover allowances for commercial development to 40 percent and 55 percent with transfers and, for residential development, reduces it to 30 percent and 40 percent with transfers. The LWO introduced a water quality buffer zone, and set impervious cover limits of up to 18 percent and 15 percent, respectively, for single-family and commercial development in this zone.
The Comprehensive Watersheds Ordinance (CWO) was adopted in 1986, superceded previous watershed ordinances and extended water quality protection throughout the City of Austin's planning area to all but the urban watersheds. While similar in some respects to its predecessors, the CWO contained a number of significant innovations. For the first time, watersheds that do not provide a portion of our drinking water received significant water quality protection. The CWO was also the first ordinance to use net site area (NSA) impervious cover calculations instead of calculations based on gross site area (GSA). GSA includes the entire site, while NSA requirements include only a site's buildable areas and can reduce overall impervious cover. The ordinance included other firsts too, such as the designation of critical environmental features and provisions for their protection. The CWO also began to organize watersheds into groups based on their relationship to 1) the City's water supply, in particular Lake Austin, 2) the Barton Springs Edwards Aquifer recharge zone and to some extent the Northern Edwards Aquifer and to 3) the degree of urbanization within a watershed, i.e. urban, suburban or rural. Urban watershed protections were incorporated by amendment into the LDC in 1991. The Urban Watersheds Ordinance (UWO) amendments did not place impervious cover limits on new development but did require water quality control structures to treat stormwater runoff. The UWO included other requirements that: allowed for fee-in-lieu of payments instead of building water quality control structures when approved by the Director of the Watershed Protection Department and established critical water quality zones with their attendant development restrictions in watersheds outside of the central business district.
The Save Our Springs Ordinance (SOS) was adopted in 1992 and differed from its predecessors because it became law by citizen initiative. Two ordinances worth noting preceded the SOS Ordinance: the Interim and Composite Ordinances. These ordinances addressed development in the Barton Springs Zone, which includes Barton Creek and the other creeks draining to, or crossing, the Edwards Aquifer recharge zone. Highlights of these ordinances included: the first requirements for non-degradation (based on stormwater discharge concentrations), and provisions that excluded variances unless a demonstrable improvement in water quality was shown. Variances, which made departures from an ordinance permissible, were a general feature of watershed ordinances up until this time.
The SOS Ordinance, applied throughout the Barton Springs Zone, required: non- degradation (based on total average annual loading), and lowered impervious cover to 15 percent NSA for all development in the recharge zone, 20 percent NSA for development in the Barton Creek portion of the contributing zone and 25 percent NSA for development in the remaining portions of the contributing zone in Williamson, Slaughter, Bear, Little Bear and Onion Creeks. The City of Austin Watershed Regulations Summary summarizes the current watershed regulations by zone and watershed classification and the City of Austin Watershed Regulation Area Map illustrates where those watersheds are located.