Using Stormwater Incentives for Ordinance Adoption
Crafting a strong watershed ordinance in Texas
Has your community or agency recommended a watershed protection ordinance that was perceived to be “good” but fell flat on its face in the public forum? Or, how often have you seen a proposed ordinance presented to elected officials for approval get beaten up in the subsequent public debate? While the ordinance failure disappoints officials and ordinance supporters, two long-term consequences can occur: the loss of public trust in local government to bring forward an effective watershed ordinance and, more importantly, the governing body’s reluctance to pursue ordinance creation. A theme common to ordinance failures is the lack of a thorough stakeholder process prior to the elected officials’ ordinance deliberations.
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| Sandy Creek arm of Lake Travis during drought (2006) |
A stakeholder is defined in Webster’s as “a person entrusted with the stakes of two or more bettors.” Though a watershed protection ordinance is not a bet, the stakes can be high with many different “bettors” involved in the process, and each desperately wants to win the stakes. Successfully hedging one’s stakes can mean better water-quality protection to one person or unwanted development cost to another. So the question must be asked: What type of process must be pursued to gain broad watershed ordinance stakeholder support before approaching the governing body for approval?
This article describes the Lower Colorado River Authority’s (LCRA’s) water-quality protection stakeholder process in central Texas to revise two nonpoint-source (NPS) pollution ordinances in response to community input to protect the Highland Lakes and the spring-fed crystal clear Hill Country streams. To gain input and support of ordinance revisions, LCRA recruited a diverse stakeholder group from rural areas, business, land development, environmental leaders, and city and county officials. During the process, the roadblocks to consensus were eliminated through the introduction of alternative development standards, innovative best management practice (BMP) solutions, and stormwater credits.
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| Bee Creek pool illuminates clear baseflow. |
Removing Roadblocks to Consensus
These incentives reduced permitting fees and permitting time when low-impact development techniques and stormwater credits were utilized. In the end, the process required 18 months of stakeholder involvement, initially individual meetings between LCRA staff and prospective stakeholders and then 20 stakeholder meetings with two committees to educate, discuss, draft, and revise the ordinance to gain overall committee consensus. The process success was reflected at the LCRA board meeting on November 16, 2005, when environmental leaders, landowners, and development engineers supported the new water-quality protection rules. Jon Beall of the Save Barton Creek Association said, “In a battle to save our clean water in the Hill Country, LCRA can become a key player in that role with the revision to this ordinance. We are taking a step forward in the right direction with this ordinance and look forward to its continued evolution.” A landowner andfounding member of the Texas Landowner Conservancy, a group dedicated to property rights protection, stated, “I commend LCRA and the stakeholder committee on a scientifically founded set of rules that are an improvement on anything heretofore. Also I would like to thank LCRA for the dialogue granted to private property owners, and I feel like certain changes were made in the course of the process to protect property rights.”
Minutes later, the LCRA Board of Directors unanimously adopted the Highland Lakes Watershed Ordinance with no opposition or meeting fireworks since debate was not necessary on the politics and technical aspects of watershed protection. The efficient stakeholder process was run entirely by LCRA staff with the assistance of an engineering consultant to craft innovative BMP suites and technical manual revisions at a total consultant cost near $55,000.
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| Hamilton Pool receives flow from a waterfall. |
The Highland Lakes
LCRA manages a large part of the Texas Colorado River whose basin begins near the New Mexico border and discharges into the Gulf of Mexico near Houston, containing 42,240 square miles. The river is more than 850 miles long. Near Austin, a chain of five reservoirs named the Highland Lakes were created from 1937 to 1951 with 50,000 acres of surface area and provide drinking water, recreation, and power generation to the people of central Texas. Lake Travis, the most popular of the five, has exceptional water clarity and is well known for swimming, boating, scuba diving, and fishing and is ranked the clearest lake in Texas. The upper four lakes exhibit high water quality and serve as popular recreation destinations. Each year, recreation and tourism connected to the lakes pump over $20 million into the local economies.
Previous NPS Ordinances
Due to early 1980s urbanization and proximity to Austin, LCRA adopted two water-quality protection ordinances, one in 1989 titled the “Lake Travis Nonpoint Source (NPS) Pollution Control Ordinance,” which includes Austin’s outer suburbs, and the “Upper Highland Lakes NPS Control Ordinance” in 1992 for the upper four lakes. The NPS ordinances had essentially the same water-quality protection measures providing 70% management of total suspended solids (TSS), total phosphorus (TP), and oil and grease (O&G) generated by the development but were very different relating to exempt status. The differences arose primarily to gain some support for Upper Highland Lakes NPS Ordinance adoption since there was little local approval over concerns of negative impact to economic growth. Lisa Hatzenbuehler, manager of LCRA’s Water Resource Protection Division, who was involved in the Upper Highland Lakes Ordinance adoption process, says, “This ordinance was all about compromise to get water-quality protection in place for the upper lakes with the presumption it could be revised in the near future. However, the political climate never warmed up and inconsistencies relating to fairness and exemptions remained for 15 years. At that time, the Lake Travis region was quite different from the upper lakes region, both development-wise and politically.”
Fast forward to 2004. The rural counties experienced a 75% population growth. Development is similar in both ordinance jurisdictions. The public and development community listed fairness experiences that led to greatly differing water-quality protection costs and desired data to verify ordinance effectiveness, and stormwater protection science has substantially evolved. Mix in headline news stories of a 1,000-acre development project with major construction sediment discharges and there is a recipe for an effort to revise the NPS ordinances throughout the 1,200-square-mile jurisdictional area that encompasses three counties and 18 cities.
Ordinance Writing:
More a Negotiation Than a Technical Process
Recruiting Diverse Stakeholders
Due to the ordinance adoption challenges 15 years earlier, staff met with more than 50 individuals in the spring of 2004, usually in one-on-one meetings, to hear their NPS ordinance concerns and recommendations. Some important issues we heard were:
- Do ponds really work? What happens to the captured pollutants?
- The NPS ordinances allow a 30% increase in pollution. Is that too much?
- How effective is the ordinance in protecting the creeks and lakes?
- Include landscaping practices in the BMP design to improve appearance.
- The NPS ordinances allow major water-quality treatment facilities in the creek.
- Incorporate buffer zones along the creek to aid in water-quality protection.
- Encourage decentralized stormwater management systems.
- Challenge in BMP design is managing phosphorus; provide alternatives to minimize water-quality cost.
Since two ordinances existed, two stakeholder committees were formed, mostly of individuals we met with in the one-on-one information-gathering meetings. To provide some backdrop on the importance of two committees, many people in the Upper Highland Lakes area still questioned the need and benefits of the ordinance while many Travis County residents felt the ordinance should be strengthened. At the outset, the stakeholders had no trouble expressing their views on water-quality protection and their general differences on watershed protection and LCRA’s role. Now the task was to keep the stakeholders actively involved and incorporate their input to revise the NPS ordinances.
Ordinance Fairness Addressed Through Alternate Standards
Under the Upper Highland Lakes NPS Ordinance, a development with less than 1 acre of new impervious cover was exempt from the ordinance. This was one of the compromise issues to gain ordinance adoption in 1992 yet caused fairness issues since many projects were able to create site plans with just under 1 acre of impervious cover to avoid constructing BMPs and the LCRA permitting process. While many site developments could be created to build less than 1 acre of impervious cover, other commercial development projects exceeded 1 acre of impervious cover to satisfy their business needs. These sites had to comply with the NPS ordinance, frequently constructing small water-quality basins such as sand-filtration basins, wet ponds, and extended detention basins. Often, business owners were unaware of the NPS ordinance and not prepared to incorporate the stormwater facilities into their site plan or project budget. The situation was exacerbated when the owner discovered the business next door did not construct water-quality treatment due to an exemption. For example, a site with an area of 1.2 acres would propose 0.95 acre of impervious cover and remain exempt from the ordinance requirements. Another site might have an area of 1.4 acres and need 1.1 acres of impervious cover for its business. To comply with the NPS ordinance, the second site could provide a sand filtration basin with a volume near 6,000 cubic feet in combination with a filter strip to manage the TSS, TP, and O&G. Business owners felt at a competitive disadvantage when complying with the ordinance.
To address this fairness issue and broaden water-quality protection, staff suggested to the stakeholders a reduction of the impervious cover exemption from 1 acre (43,560 square feet) to 10,000 square feet. This would require essentially all projects to provide water-quality protection. The proposal was not well received by the development and business stakeholders due to the anticipated cost and maintenance, while other stakeholders found small water-quality basins to be unattractive mosquito breeding grounds. The consensus-based process was stuck on two highly contentious issues: the proposal for water-quality treatment on all development sites versus the expense and appearance of water-quality basins. Without the stakeholder process, staff could not have understood the underlying issues that frustrated so many or been able to devise a solution to move the process forward.
Enhanced Filter Strip Designs as Alternate Compliance Standards
Staff responded by generating filter strip designs as standalone BMPs for small commercial projects to treat runoff and eliminate water-quality basins that were decried by so many committee members. The concept was shared with the project consulting engineer, James Miertschin and Associates Inc. (JMA), which provided technical consultation to develop BMP solutions. After extensive national filter strip research, alternate standards were crafted for commercial projects less than 3 acres. This acreage was selected as an appropriate size for compromise and the belief that site grading design could promote sheet flow runoff to ensure filter strip integrity. JMA developed three filter strip options for commercial tracts less than 3 acres that were termed alternate standards for commercial development.
The filter strips were designed to manage 70% of the post-development TSS, TP, and O&G load by utilizing dense vegetation and soil to detain, filter, and infiltrate stormwater runoff. Since the solution was quite technical, staff created a subcommittee of engineers and interested realtors to consider the design approach. The concept was rolled out to the subcommittee with site plan examples to illustrate vegetated filter strips, water-quality treatment, and their coordination with local landscape ordinances.
Under commercial alternate standards, the 1.2-acre site with 0.95 acre of impervious cover would have the option of providing 0.16 acre of engineered filter strip or 0.11 acre of engineered infiltration filter strip for water-quality protection. From a larger project perspective, a 3-acre site with 80% impervious cover has the option of utilizing an engineered filter strip with an area of 0.40 acre or an engineered infiltration filter strip of 0.27 acre. For comparison purposes, the NPS ordinances would have required a water-quality basin of nearly 13,000 cubic feet and a vegetated filter strip.
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| Vegetated infiltration strip after 3-inch rainfall. |
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| Completed
infiltration
strip |
The subcommittee stakeholders quickly grasped the commercial alternate standards’ cost and aesthetic benefits. They became a supporter of the plan and shared the results with the committee. We observed that the stakeholder members listened intently to their peers. Staff stepped back and the subcommittee detailed the approach and gained general stakeholder consensus on filter strips and exempt status.
On challenging issues, form a subcommittee to develop a solution and share with the full stakeholder committee; you will be pleased with the result.
A technical solution was in the making for small commercial projects, but staff needed to address a common theme echoed by stakeholder committee developers that uncertainty during the permitting process could cause project delays and expense overruns. To overcome this concern, staff suggested that compliance with the commercial alternate standards would lead to a fast-track permit and reduced permitting fees. Since only three calculations were necessary (impervious cover percentage, water-quality volume, and filter strip area), staff felt confident that a project review and permit could be issued within 30 days of receipt of an administratively complete application. By offering alternate standards that simplified the design process, minimized the cost of water-quality protection, and ensured a 30-day permitting time, the stakeholder committee reached general consensus on addressing the fairness issue by agreeing to reduce the 1-acre exemption to 10,000 square feet. It was recognized that these alternate standards did not fully manage the one-year runoff volume for creek bank erosion control. Staff and the stakeholder committee believed the trade-off for gaining water-quality treatment from all sites was a victory for ordinance fairness, stormwater pollution management, and BMP appearance. Brad Shaw, P.E., owner of Highland Lakes Engineering and a stakeholder member who served on the subcommittee, says, “The filter strip philosophy is a much more user-friendly approach to clean stormwater when compared to water-quality basins that often are located on expensive real estate. The vegetative filter strip provides a landscape that is pleasing and does not impair the use of the land and tax base.”
Impervious Cover, Stormwater Credits, and LID Incentives
Now that small commercial site exemption and fairness issues were resolved, it was time to tackle large-development water-quality protection and low-impact development incentives. The NPS ordinances offered a large-lot development incentive combined with roadside swales, where if each single-family lot was greater than 1 acre, the development did not provide water-quality calculations and structural BMPs. It was an attempt at low-impact development in the early 1990s. However, development sprawl was possible through minimum lot size requirements.
As our stakeholder process began, LCRA staff believed that water-quality protection should be based on impervious cover, not lot size. In addition, the NPS ordinances did not attach impervious cover limits to 1-acre lots resulting in a number of lakeside “mega-houses” that concerned some stakeholders since they felt little stormwater-quality treatment occurred on paved property.
The debate on impervious cover and water quality is lengthy, with many different schools of thought. In the central Texas region, most City of Austin watershed ordinances and the Texas Commission on Environmental Quality Edwards Aquifer Protection Rules do not require structural controls when the impervious cover is less than 20%. The sensitive Barton Springs zone under a separate City of Austin aquifer protection ordinance limits the maximum impervious cover to 15% and requires stormwater treatment as well. Since the City of Austin has land-use control authority and LCRA does not, staff knew from the beginning that the revised ordinance would never include an impervious cover limitation.
Data from around the country revealed in some regions that water quality and channel degradation were noted at impervious cover levels in the 5% to 10% range. Other studies showed different findings with many documenting significant channel degradation and habitat loss at impervious cover levels exceeding 25% to 30%.
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| Lake Travis cove with large homes |
Staff initially proposed to the stakeholder committees an impervious cover level of 5% to gain compliance with alternate standards development to avoid structural BMPs. It became readily apparent that only large sprawling development would achieve this low impervious cover level. The development community stakeholders made it clear that few projects could attain this 5% impervious cover level and there were no financial incentives to strive for this goal.
Another central Texas water-quality stakeholder process was coming to conclusion and presented data recommending 15% gross impervious cover to protect water quality. This approach appealed to LCRA due to its simplicity and provision of water-quality protection.
Staff presented the gross impervious cover level of 15% in combination with hydrologic design that mimics natural flow patterns since it is important to maintain a link between impervious cover and conveyance through vegetated systems instead of curb and gutter and storm drain pipe. The development stakeholders believed that anticipated development patterns encroaching into the watershed ordinance jurisdiction could rarely achieve this limit.
To attempt to create an attainable low-impact development incentive and armed with the knowledge of “Maryland Stormwater Design Manual” options, staff created a set of impervious cover credits. The stormwater credits are optional incentives that can be incorporated to reduce a project’s effective impervious cover to 15% and gain alternate standards compliance without structural BMPs and reduce permitting time and cost.
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| Stormwater credit, placement of porous pavement to retain parking lot runoff volume |
Credits to Reduce Impervious Cover
Staff proposed porous concrete pavement, rainwater harvesting, soil amendment and conservation landscaping, disconnection of rooftop runoff, and natural area preservation as options to manage a development’s effective impervious cover. Each project has multiple options at the developer’s discretion to manage water quality within the overall project scope. By incorporating credits, stormwater became more of a resource that was not casually discarded within the urban environment. For example, porous pavement aids groundwater recharge, soil amendment retains rainfall on the site resulting in less lawn water demand, and rainwater harvesting provides water for use in the home or landscape.
The stormwater credit options reduced effective impervious cover and runoff volume and offered feasible, cost-effective approaches to meet the alternate standards 15% impervious cover limit and were endorsed by the stakeholder committees. Rick Wheeler, P.E., stakeholder, member, and president of Malone/Wheeler Inc., development planning and design consulting engineers, tells us, “The watershed ordinance is going to be a very effective tool because it provides property owners, developers, and public entities that have to meet the water-quality requirements with a whole menu and variety of options of how to accomplish that. Compliance is gained through the use of various BMPs. It’s not a rigid process that everyone has to do the same thing. You can customize your water-quality program along with your project design.”
After one year, we have found that most single-family development projects gain compliance with the alternate standards, many using stormwater credits. Once the design methodologies are explained in the pre-development planning meeting, developers seek this path to avoid costly structural water-quality controls, reduce permitting time, limit their liability due to standing water in basins, improve the development appearance by using natural flow conveyance systems, and avoid saddling the homeowners’ association with a long-term maintenance obligation.
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| Typical Hill Country creek section found on Hamilton Creek. |
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| Limestone ledge on Bee Creek, commonly found on area creeks |
Use of Local Media/Current Events—Creek Buffer Zones
The NPS ordinances did not contain creek buffer zones or any restrictions on constructing water-quality treatment facilities within the creeks, which run clear over the limestone beds, with TSS levels less than 2 milligrams per liter. Often, projects proposed “regional” water-quality treatment by constructing earthen embankments across the valley to impound stormwater runoff in extended detention basins or wet ponds. Some projects attempted to provide erosion and sediment control within the creeks by utilizing rock berms, silt fences, and other techniques to retain sediment in the channel before leaving the site. In most cases, staff were able to direct erosion and sediment control practices up-gradient of the receiving creek but were not as successful in guiding permanent treatment facilities to the uplands area.
In 2003, a development project over 1,000 acres in area began clearing native vegetation in terrain with slopes in excess of 5% to 10%. This included the grading of a regional extended detention/flood control basin with a drainage area of 650 acres. The facility is located on a tributary to Lick Creek, an ephemeral creek that relies on springs and seeps to sustain baseflow. While several hundred acres of land were disturbed and the basin was excavated, the rains began and continued for the next year, exceeding the average annual rainfall by nearly 50%. The erosion controls were overwhelmed and the once-clear waters were monitored at TSS levels greater than 500 milligrams per liter and in some cases more than 1,500 milligrams per liter. Due to the erosion and sediment problems, LCRA used the Lake Travis NPS enforcement authority to shut down the project on two occasions and twice fined the developer for non-compliance. More importantly, the downstream residents who lounged by the creek waterfalls and swam in the pools were very upset with the project and its impact on the creek they loved so much.
The property owners organized and contacted the local media, both newspaper and television. Throughout the spring and summer of 2004 while the contractor was plagued by sediment discharges and poor erosion control practices, stories appeared on the Austin American-Statesman front page and on the television nightly news. The articles and features graphically described the transformation of a pristine creek to one with turbid waters. As the project impaired the Lick Creek waters, the general public, engineers, and developers of the region received an education on creek construction practices.
The stakeholder process began in the fall of 2004 and everyone had heard of Lick Creek. Staff’s first draft ordinance proposal included creek buffer zones to prohibit construction and land-disturbing ventures in the riparian corridor. Also, buffer zones were viewed as a water-quality insurance policy if upstream BMPs failed or were not properly maintained.
The buffer zone proposal was no surprise due to the notoriety of Lick Creek. Also, many developers and engineers were already experienced with the buffer zones found in the City of Austin watershed ordinances. Since headwater stream protection is believed to serve a valuable water-quality and ecosystem protection role, the buffer zones were proposed to begin at a drainage area of 5 acres. This proposal was a big leap from the local ordinance buffer zones, which start at a 64-acre watershed area. Protection of creeks jumped to the forefront of the stakeholder process with the belief being if creek water quality is protected the lakes will maintain high water quality.
Surprisingly, after some debate and a subcommittee meeting with the engineers, there was general consensus in support of buffer zones. This is primarily due to the buffer zone options that were included in the ordinance. In addition to prescribed creek centerline setbacks based on watershed drainage area as found in the City of Austin regulations, the ordinance offered the option of defining the 100-year floodplain and adding 25 feet on each side of the floodplain boundary. The end result was a flexible buffer zone that provides multiple benefits: water-quality treatment, flood protection, habitat corridors, and room for potential creek migration.
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| Creek buffer zone along Hamilton Creek |
By being provided with options to define buffer zone width, the development community is more willing to support regulations that employ engineering solutions.
Without the extensive media spotlight on the Lick Creek problems, it is unlikely that headwater stream buffer zones would have achieved general consensus from the stakeholder committee. Media and public awareness can play a vital role in building support for regulatory measures to prevent the occurrence of similar problems in the future.
Treating Runoff/Managing Hydrology for Channels/Innovative BMPs
Most watershed ordinances throughout the nation focus on TSS management, typically in the range of 70% to 90% to reduce pollutant runoff from a development site. Based on water-quality data, the Highland Lakes are nutrient-limited, with phosphorus as the limiting nutrient. Therefore, the earlier NPS ordinances managed TP with TSS to protect the lakes’ clarity and quality. Since TP includes particulate and dissolved components, it is more difficult to remove from runoff than TSS; thus, a BMP’s type, size, and cost are driven by its ability to treat TP.
The stakeholder process began with a majority of the Lake Travis committee members supporting a TSS, TP, and O&G removal increase to 90% while the Upper Highland Lakes committee firmly believed the pollutant management levels should remain at 70%. This latter committee felt that raising the standards would increase large stormwater management costs and adversely impact economic development.
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| Bioretention with sand overflow under construction
(top) and completed (bottom) |
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Another stakeholder goal was to simplify the ordinance compliance process to reduce cost and time. Staff concurred and, in coordination with JMA, reviewed local bankfull and water-quality data and determined that the one-year storm (1.93 inches in three hours) could serve as a design target to manage channel erosion and water-quality basin design. Using this storm, JMA verified that basins would treat 90% of the annual pollutant load.
Managing for channel erosion can be accomplished by peak flow rate targets through a detention requirement or through volume control to attempt to closely mimic natural hydrologic conditions. Staff was fully aware that effective peak-to-peak detention can be manipulated through hydrologic parameter adjustments to reduce pond size and, in most cases, completely miss the management of frequent storms, which can be the channel-forming storms that do the most stream “work” over time.
Staff felt that volume control was essential in managing the common storm events and channel erosion. To ensure the volume approach was successful, JMA developed a runoff volume relationship based on effective impervious cover percentage. More importantly, by requiring the design storm to be released from basins over a 24- to 40-hour period, discharge resembles natural conditions and eliminates erosive discharges to the receiving water body.
To completely address ordinance fairness, staff believed one ordinance was necessary for the jurisdictional area, not two, due to the similarity of development type and growth patterns. However, a roadblock stood in the path of one ordinance, the stakeholder committee pollutant removal recommendations, 90% for one and 70% for the other.
Behind the stakeholder process scenes, staff coordinated with JMA to develop innovative BMP suites based on runoff volume from the one-year storm, not pollutant loading calculations as prescribed in the previous NPS ordinances. In addition, one storm, not two, would be used to design BMPs, thus meeting the stakeholder’s simplification goal. The BMP suites were composed of numerous options using primary BMPs such as bioretention, extended detention basins, sand filter systems, wet ponds, and wetland basins to treat pollutants and manage runoff volume. Additionally, secondary BMPs such as infiltration trenches, infiltration basins, and vegetated filter strips were available to manage TP and return basin discharges to sheet flow. The BMP suites were established to manage 70% to 75% of the design pollutants (TSS, TP, O&G) by relying on design volume runoff and their expected pollutant treatment performance.
LCRA had the luxury of implementing innovative BMPs through an EPA 319 grant. One BMP example is a bioretention basin combined with a sand filter overflow to achieve a pond depth of 2 feet to reduce the basin footprint and cost. This BMP system can meet the TP removal requirements and does not require a secondary BMP. Another BMP suite that shows great promise is an extended detention basin followed by an infiltration trench. The maximum water depth is 8 feet, thus enabling a small basin surface area. Extended detention minimizes sediment discharge to the infiltration trench and regulates flow to promote design storm infiltration. If runoff discharges from the trench, it will do so in a sheet flow manner to the downstream creek buffer zone, further polishing stormwater runoff.
By taking the runoff volume approach, a project designer would no longer need to compute pollutant loads and calculate 70% or 90% removal. Staff believed the built-in performance based on runoff volume could move the stakeholder discussions toward consensus and get past the 70% or 90% pollutant removal debate.
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| Rainstorm at extended detention basin/infiltration trench best management practice suite |
This concept was presented at the last stakeholder meeting as we summed the total Highland Lakes Watershed Ordinance benefits. Converting to water-quality volume ended the debate on pollutant removal percentages and did not sacrifice water-quality protection. Instead, the two committees realized the benefit of this direction: BMPs would remain similar in size and cost to the previous NPS ordinances, satisfying the Upper Highlands committee. The new buffer zones and education requirements were recognized as worthy additions by the Lake Travis committee to achieve the 90% goal of most committee members. This was the final piece in the stakeholder process to bring the two ordinances to one and move forward to adoption.
Compromise on pollution management targets was achieved through revising the computation approach and providing water-quality volume control to manage channel erosion.
Highland Lakes Watershed Ordinance
The 18-month stakeholder process led to the development of five key performance standards to protect water quality and creek geomorphology. These measures are:
- Pre-development planning for single-family subdivisions greater than 20 acres and commercial tracts larger than 3 acres to guide the development team in planning and designing water-quality protection measures and reducing construction cost
- Manage 70% to 75% of the TSS, TP, and O&G generated by the project and minimize creek degradation by managing the one-year storm design volume in approved BMP suites. Alternate standards are provided for commercial tracts less than 3 acres and development projects with effective impervious cover less than 15%. Incentives for low-impact development include stormwater credits and reduced permitting time and cost.
- Protect creeks and waterways by defining buffer zones when the drainage area exceeds 5 acres. The buffer zones remain free of construction or other alterations except for utility and roadway crossings and low-impact parks.
- Erosion and sedimentation throughout construction is managed by the many BMP options found in the technical manual and consistent with the stormwater pollution prevention plan requirements of the Texas Commission on Environmental Quality.
- Water-quality education is provided annually to neighborhood residents to illustrate the proper use, handling, and disposal of fertilizers, pesticides, herbicides, household chemicals, solid waste, and pet waste.
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Lessons Learned
Our experience revealed that successful public participation is more of a negotiated process than a technical process and requires compromise; thus, the committee must have the leadership of technical staff that can communicate water-quality protection to the general public and, most importantly, listen and respond to the committee members’ perspectives. Pepper Morris, Lick Creek resident and stakeholder member, voiced her opinion on the process at the LCRA board meeting: “After fighting for over two years to fix Lick Creek, I have taken to heart the word compromise and appreciate the LCRA stakeholder process to keep us on track, listen, and digest information from the committee. Is the ordinance perfect? Probably not, but our compromises are to be commended to improve water-quality protection.”
By gaining consensus at the committee level with a diverse group of stakeholders, the LCRA Board was not asked to make tough technical decisions. The Highland Lakes Watershed Ordinance process contained many technical aspects, but in the end it was a process about negotiation, information sharing, and deep topic discussions so the diverse stakeholder members could work together to a compromise solution that is more based on science than driven by rhetoric.
September 2007
Using Stormwater Incentives for Ordinance Adoption
Crafting a strong watershed ordinance in Texas
Has your community or agency recommended a watershed protection ordinance that was perceived to be “good” but fell flat on its face in the public forum? Or, how often have you seen a proposed ordinance presented to elected officials for approval get beaten up in the subsequent public debate? While the ordinance failure disappoints officials and ordinance supporters, two long-term consequences can occur: the loss of public trust in local government to bring forward an effective watershed ordinance and, more importantly, the governing body’s reluctance to pursue ordinance creation. A theme common to ordinance failures is the lack of a thorough stakeholder process prior to the elected officials’ ordinance deliberations.
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| Sandy Creek arm of Lake Travis during drought (2006) |
A stakeholder is defined in Webster’s as “a person entrusted with the stakes of two or more bettors.” Though a watershed protection ordinance is not a bet, the stakes can be high with many different “bettors” involved in the process, and each desperately wants to win the stakes. Successfully hedging one’s stakes can mean better water-quality protection to one person or unwanted development cost to another. So the question must be asked: What type of process must be pursued to gain broad watershed ordinance stakeholder support before approaching the governing body for approval?
This article describes the Lower Colorado River Authority’s (LCRA’s) water-quality protection stakeholder process in central Texas to revise two nonpoint-source (NPS) pollution ordinances in response to community input to protect the Highland Lakes and the spring-fed crystal clear Hill Country streams. To gain input and support of ordinance revisions, LCRA recruited a diverse stakeholder group from rural areas, business, land development, environmental leaders, and city and county officials. During the process, the roadblocks to consensus were eliminated through the introduction of alternative development standards, innovative best management practice (BMP) solutions, and stormwater credits.
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| Bee Creek pool illuminates clear baseflow. |
Removing Roadblocks to Consensus
These incentives reduced permitting fees and permitting time when low-impact development techniques and stormwater credits were utilized. In the end, the process required 18 months of stakeholder involvement, initially individual meetings between LCRA staff and prospective stakeholders and then 20 stakeholder meetings with two committees to educate, discuss, draft, and revise the ordinance to gain overall committee consensus. The process success was reflected at the LCRA board meeting on November 16, 2005, when environmental leaders, landowners, and development engineers supported the new water-quality protection rules. Jon Beall of the Save Barton Creek Association said, “In a battle to save our clean water in the Hill Country, LCRA can become a key player in that role with the revision to this ordinance. We are taking a step forward in the right direction with this ordinance and look forward to its continued evolution.” A landowner andfounding member of the Texas Landowner Conservancy, a group dedicated to property rights protection, stated, “I commend LCRA and the stakeholder committee on a scientifically founded set of rules that are an improvement on anything heretofore. Also I would like to thank LCRA for the dialogue granted to private property owners, and I feel like certain changes were made in the course of the process to protect property rights.”
Minutes later, the LCRA Board of Directors unanimously adopted the Highland Lakes Watershed Ordinance with no opposition or meeting fireworks since debate was not necessary on the politics and technical aspects of watershed protection. The efficient stakeholder process was run entirely by LCRA staff with the assistance of an engineering consultant to craft innovative BMP suites and technical manual revisions at a total consultant cost near $55,000.
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| Hamilton Pool receives flow from a waterfall. |
The Highland Lakes
LCRA manages a large part of the Texas Colorado River whose basin begins near the New Mexico border and discharges into the Gulf of Mexico near Houston, containing 42,240 square miles. The river is more than 850 miles long. Near Austin, a chain of five reservoirs named the Highland Lakes were created from 1937 to 1951 with 50,000 acres of surface area and provide drinking water, recreation, and power generation to the people of central Texas. Lake Travis, the most popular of the five, has exceptional water clarity and is well known for swimming, boating, scuba diving, and fishing and is ranked the clearest lake in Texas. The upper four lakes exhibit high water quality and serve as popular recreation destinations. Each year, recreation and tourism connected to the lakes pump over $20 million into the local economies.
Previous NPS Ordinances
Due to early 1980s urbanization and proximity to Austin, LCRA adopted two water-quality protection ordinances, one in 1989 titled the “Lake Travis Nonpoint Source (NPS) Pollution Control Ordinance,” which includes Austin’s outer suburbs, and the “Upper Highland Lakes NPS Control Ordinance” in 1992 for the upper four lakes. The NPS ordinances had essentially the same water-quality protection measures providing 70% management of total suspended solids (TSS), total phosphorus (TP), and oil and grease (O&G) generated by the development but were very different relating to exempt status. The differences arose primarily to gain some support for Upper Highland Lakes NPS Ordinance adoption since there was little local approval over concerns of negative impact to economic growth. Lisa Hatzenbuehler, manager of LCRA’s Water Resource Protection Division, who was involved in the Upper Highland Lakes Ordinance adoption process, says, “This ordinance was all about compromise to get water-quality protection in place for the upper lakes with the presumption it could be revised in the near future. However, the political climate never warmed up and inconsistencies relating to fairness and exemptions remained for 15 years. At that time, the Lake Travis region was quite different from the upper lakes region, both development-wise and politically.”
Fast forward to 2004. The rural counties experienced a 75% population growth. Development is similar in both ordinance jurisdictions. The public and development community listed fairness experiences that led to greatly differing water-quality protection costs and desired data to verify ordinance effectiveness, and stormwater protection science has substantially evolved. Mix in headline news stories of a 1,000-acre development project with major construction sediment discharges and there is a recipe for an effort to revise the NPS ordinances throughout the 1,200-square-mile jurisdictional area that encompasses three counties and 18 cities.
Ordinance Writing:
More a Negotiation Than a Technical Process
Recruiting Diverse Stakeholders
Due to the ordinance adoption challenges 15 years earlier, staff met with more than 50 individuals in the spring of 2004, usually in one-on-one meetings, to hear their NPS ordinance concerns and recommendations. Some important issues we heard were:
- Do ponds really work? What happens to the captured pollutants?
- The NPS ordinances allow a 30% increase in pollution. Is that too much?
- How effective is the ordinance in protecting the creeks and lakes?
- Include landscaping practices in the BMP design to improve appearance.
- The NPS ordinances allow major water-quality treatment facilities in the creek.
- Incorporate buffer zones along the creek to aid in water-quality protection.
- Encourage decentralized stormwater management systems.
- Challenge in BMP design is managing phosphorus; provide alternatives to minimize water-quality cost.
Since two ordinances existed, two stakeholder committees were formed, mostly of individuals we met with in the one-on-one information-gathering meetings. To provide some backdrop on the importance of two committees, many people in the Upper Highland Lakes area still questioned the need and benefits of the ordinance while many Travis County residents felt the ordinance should be strengthened. At the outset, the stakeholders had no trouble expressing their views on water-quality protection and their general differences on watershed protection and LCRA’s role. Now the task was to keep the stakeholders actively involved and incorporate their input to revise the NPS ordinances.
Ordinance Fairness Addressed Through Alternate Standards
Under the Upper Highland Lakes NPS Ordinance, a development with less than 1 acre of new impervious cover was exempt from the ordinance. This was one of the compromise issues to gain ordinance adoption in 1992 yet caused fairness issues since many projects were able to create site plans with just under 1 acre of impervious cover to avoid constructing BMPs and the LCRA permitting process. While many site developments could be created to build less than 1 acre of impervious cover, other commercial development projects exceeded 1 acre of impervious cover to satisfy their business needs. These sites had to comply with the NPS ordinance, frequently constructing small water-quality basins such as sand-filtration basins, wet ponds, and extended detention basins. Often, business owners were unaware of the NPS ordinance and not prepared to incorporate the stormwater facilities into their site plan or project budget. The situation was exacerbated when the owner discovered the business next door did not construct water-quality treatment due to an exemption. For example, a site with an area of 1.2 acres would propose 0.95 acre of impervious cover and remain exempt from the ordinance requirements. Another site might have an area of 1.4 acres and need 1.1 acres of impervious cover for its business. To comply with the NPS ordinance, the second site could provide a sand filtration basin with a volume near 6,000 cubic feet in combination with a filter strip to manage the TSS, TP, and O&G. Business owners felt at a competitive disadvantage when complying with the ordinance.
To address this fairness issue and broaden water-quality protection, staff suggested to the stakeholders a reduction of the impervious cover exemption from 1 acre (43,560 square feet) to 10,000 square feet. This would require essentially all projects to provide water-quality protection. The proposal was not well received by the development and business stakeholders due to the anticipated cost and maintenance, while other stakeholders found small water-quality basins to be unattractive mosquito breeding grounds. The consensus-based process was stuck on two highly contentious issues: the proposal for water-quality treatment on all development sites versus the expense and appearance of water-quality basins. Without the stakeholder process, staff could not have understood the underlying issues that frustrated so many or been able to devise a solution to move the process forward.
Enhanced Filter Strip Designs as Alternate Compliance Standards
Staff responded by generating filter strip designs as standalone BMPs for small commercial projects to treat runoff and eliminate water-quality basins that were decried by so many committee members. The concept was shared with the project consulting engineer, James Miertschin and Associates Inc. (JMA), which provided technical consultation to develop BMP solutions. After extensive national filter strip research, alternate standards were crafted for commercial projects less than 3 acres. This acreage was selected as an appropriate size for compromise and the belief that site grading design could promote sheet flow runoff to ensure filter strip integrity. JMA developed three filter strip options for commercial tracts less than 3 acres that were termed alternate standards for commercial development.
The filter strips were designed to manage 70% of the post-development TSS, TP, and O&G load by utilizing dense vegetation and soil to detain, filter, and infiltrate stormwater runoff. Since the solution was quite technical, staff created a subcommittee of engineers and interested realtors to consider the design approach. The concept was rolled out to the subcommittee with site plan examples to illustrate vegetated filter strips, water-quality treatment, and their coordination with local landscape ordinances.
Under commercial alternate standards, the 1.2-acre site with 0.95 acre of impervious cover would have the option of providing 0.16 acre of engineered filter strip or 0.11 acre of engineered infiltration filter strip for water-quality protection. From a larger project perspective, a 3-acre site with 80% impervious cover has the option of utilizing an engineered filter strip with an area of 0.40 acre or an engineered infiltration filter strip of 0.27 acre. For comparison purposes, the NPS ordinances would have required a water-quality basin of nearly 13,000 cubic feet and a vegetated filter strip.
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| Vegetated infiltration strip after 3-inch rainfall. |
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| Completed
infiltration
strip |
The subcommittee stakeholders quickly grasped the commercial alternate standards’ cost and aesthetic benefits. They became a supporter of the plan and shared the results with the committee. We observed that the stakeholder members listened intently to their peers. Staff stepped back and the subcommittee detailed the approach and gained general stakeholder consensus on filter strips and exempt status.
On challenging issues, form a subcommittee to develop a solution and share with the full stakeholder committee; you will be pleased with the result.
A technical solution was in the making for small commercial projects, but staff needed to address a common theme echoed by stakeholder committee developers that uncertainty during the permitting process could cause project delays and expense overruns. To overcome this concern, staff suggested that compliance with the commercial alternate standards would lead to a fast-track permit and reduced permitting fees. Since only three calculations were necessary (impervious cover percentage, water-quality volume, and filter strip area), staff felt confident that a project review and permit could be issued within 30 days of receipt of an administratively complete application. By offering alternate standards that simplified the design process, minimized the cost of water-quality protection, and ensured a 30-day permitting time, the stakeholder committee reached general consensus on addressing the fairness issue by agreeing to reduce the 1-acre exemption to 10,000 square feet. It was recognized that these alternate standards did not fully manage the one-year runoff volume for creek bank erosion control. Staff and the stakeholder committee believed the trade-off for gaining water-quality treatment from all sites was a victory for ordinance fairness, stormwater pollution management, and BMP appearance. Brad Shaw, P.E., owner of Highland Lakes Engineering and a stakeholder member who served on the subcommittee, says, “The filter strip philosophy is a much more user-friendly approach to clean stormwater when compared to water-quality basins that often are located on expensive real estate. The vegetative filter strip provides a landscape that is pleasing and does not impair the use of the land and tax base.”
Impervious Cover, Stormwater Credits, and LID Incentives
Now that small commercial site exemption and fairness issues were resolved, it was time to tackle large-development water-quality protection and low-impact development incentives. The NPS ordinances offered a large-lot development incentive combined with roadside swales, where if each single-family lot was greater than 1 acre, the development did not provide water-quality calculations and structural BMPs. It was an attempt at low-impact development in the early 1990s. However, development sprawl was possible through minimum lot size requirements.
As our stakeholder process began, LCRA staff believed that water-quality protection should be based on impervious cover, not lot size. In addition, the NPS ordinances did not attach impervious cover limits to 1-acre lots resulting in a number of lakeside “mega-houses” that concerned some stakeholders since they felt little stormwater-quality treatment occurred on paved property.
The debate on impervious cover and water quality is lengthy, with many different schools of thought. In the central Texas region, most City of Austin watershed ordinances and the Texas Commission on Environmental Quality Edwards Aquifer Protection Rules do not require structural controls when the impervious cover is less than 20%. The sensitive Barton Springs zone under a separate City of Austin aquifer protection ordinance limits the maximum impervious cover to 15% and requires stormwater treatment as well. Since the City of Austin has land-use control authority and LCRA does not, staff knew from the beginning that the revised ordinance would never include an impervious cover limitation.
Data from around the country revealed in some regions that water quality and channel degradation were noted at impervious cover levels in the 5% to 10% range. Other studies showed different findings with many documenting significant channel degradation and habitat loss at impervious cover levels exceeding 25% to 30%.
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| Lake Travis cove with large homes |
Staff initially proposed to the stakeholder committees an impervious cover level of 5% to gain compliance with alternate standards development to avoid structural BMPs. It became readily apparent that only large sprawling development would achieve this low impervious cover level. The development community stakeholders made it clear that few projects could attain this 5% impervious cover level and there were no financial incentives to strive for this goal.
Another central Texas water-quality stakeholder process was coming to conclusion and presented data recommending 15% gross impervious cover to protect water quality. This approach appealed to LCRA due to its simplicity and provision of water-quality protection.
Staff presented the gross impervious cover level of 15% in combination with hydrologic design that mimics natural flow patterns since it is important to maintain a link between impervious cover and conveyance through vegetated systems instead of curb and gutter and storm drain pipe. The development stakeholders believed that anticipated development patterns encroaching into the watershed ordinance jurisdiction could rarely achieve this limit.
To attempt to create an attainable low-impact development incentive and armed with the knowledge of “Maryland Stormwater Design Manual” options, staff created a set of impervious cover credits. The stormwater credits are optional incentives that can be incorporated to reduce a project’s effective impervious cover to 15% and gain alternate standards compliance without structural BMPs and reduce permitting time and cost.
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| Stormwater credit, placement of porous pavement to retain parking lot runoff volume |
Credits to Reduce Impervious Cover
Staff proposed porous concrete pavement, rainwater harvesting, soil amendment and conservation landscaping, disconnection of rooftop runoff, and natural area preservation as options to manage a development’s effective impervious cover. Each project has multiple options at the developer’s discretion to manage water quality within the overall project scope. By incorporating credits, stormwater became more of a resource that was not casually discarded within the urban environment. For example, porous pavement aids groundwater recharge, soil amendment retains rainfall on the site resulting in less lawn water demand, and rainwater harvesting provides water for use in the home or landscape.
The stormwater credit options reduced effective impervious cover and runoff volume and offered feasible, cost-effective approaches to meet the alternate standards 15% impervious cover limit and were endorsed by the stakeholder committees. Rick Wheeler, P.E., stakeholder, member, and president of Malone/Wheeler Inc., development planning and design consulting engineers, tells us, “The watershed ordinance is going to be a very effective tool because it provides property owners, developers, and public entities that have to meet the water-quality requirements with a whole menu and variety of options of how to accomplish that. Compliance is gained through the use of various BMPs. It’s not a rigid process that everyone has to do the same thing. You can customize your water-quality program along with your project design.”
After one year, we have found that most single-family development projects gain compliance with the alternate standards, many using stormwater credits. Once the design methodologies are explained in the pre-development planning meeting, developers seek this path to avoid costly structural water-quality controls, reduce permitting time, limit their liability due to standing water in basins, improve the development appearance by using natural flow conveyance systems, and avoid saddling the homeowners’ association with a long-term maintenance obligation.
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| Typical Hill Country creek section found on Hamilton Creek. |
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| Limestone ledge on Bee Creek, commonly found on area creeks |
Use of Local Media/Current Events—Creek Buffer Zones
The NPS ordinances did not contain creek buffer zones or any restrictions on constructing water-quality treatment facilities within the creeks, which run clear over the limestone beds, with TSS levels less than 2 milligrams per liter. Often, projects proposed “regional” water-quality treatment by constructing earthen embankments across the valley to impound stormwater runoff in extended detention basins or wet ponds. Some projects attempted to provide erosion and sediment control within the creeks by utilizing rock berms, silt fences, and other techniques to retain sediment in the channel before leaving the site. In most cases, staff were able to direct erosion and sediment control practices up-gradient of the receiving creek but were not as successful in guiding permanent treatment facilities to the uplands area.
In 2003, a development project over 1,000 acres in area began clearing native vegetation in terrain with slopes in excess of 5% to 10%. This included the grading of a regional extended detention/flood control basin with a drainage area of 650 acres. The facility is located on a tributary to Lick Creek, an ephemeral creek that relies on springs and seeps to sustain baseflow. While several hundred acres of land were disturbed and the basin was excavated, the rains began and continued for the next year, exceeding the average annual rainfall by nearly 50%. The erosion controls were overwhelmed and the once-clear waters were monitored at TSS levels greater than 500 milligrams per liter and in some cases more than 1,500 milligrams per liter. Due to the erosion and sediment problems, LCRA used the Lake Travis NPS enforcement authority to shut down the project on two occasions and twice fined the developer for non-compliance. More importantly, the downstream residents who lounged by the creek waterfalls and swam in the pools were very upset with the project and its impact on the creek they loved so much.
The property owners organized and contacted the local media, both newspaper and television. Throughout the spring and summer of 2004 while the contractor was plagued by sediment discharges and poor erosion control practices, stories appeared on the Austin American-Statesman front page and on the television nightly news. The articles and features graphically described the transformation of a pristine creek to one with turbid waters. As the project impaired the Lick Creek waters, the general public, engineers, and developers of the region received an education on creek construction practices.
The stakeholder process began in the fall of 2004 and everyone had heard of Lick Creek. Staff’s first draft ordinance proposal included creek buffer zones to prohibit construction and land-disturbing ventures in the riparian corridor. Also, buffer zones were viewed as a water-quality insurance policy if upstream BMPs failed or were not properly maintained.
The buffer zone proposal was no surprise due to the notoriety of Lick Creek. Also, many developers and engineers were already experienced with the buffer zones found in the City of Austin watershed ordinances. Since headwater stream protection is believed to serve a valuable water-quality and ecosystem protection role, the buffer zones were proposed to begin at a drainage area of 5 acres. This proposal was a big leap from the local ordinance buffer zones, which start at a 64-acre watershed area. Protection of creeks jumped to the forefront of the stakeholder process with the belief being if creek water quality is protected the lakes will maintain high water quality.
Surprisingly, after some debate and a subcommittee meeting with the engineers, there was general consensus in support of buffer zones. This is primarily due to the buffer zone options that were included in the ordinance. In addition to prescribed creek centerline setbacks based on watershed drainage area as found in the City of Austin regulations, the ordinance offered the option of defining the 100-year floodplain and adding 25 feet on each side of the floodplain boundary. The end result was a flexible buffer zone that provides multiple benefits: water-quality treatment, flood protection, habitat corridors, and room for potential creek migration.
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| Creek buffer zone along Hamilton Creek |
By being provided with options to define buffer zone width, the development community is more willing to support regulations that employ engineering solutions.
Without the extensive media spotlight on the Lick Creek problems, it is unlikely that headwater stream buffer zones would have achieved general consensus from the stakeholder committee. Media and public awareness can play a vital role in building support for regulatory measures to prevent the occurrence of similar problems in the future.
Treating Runoff/Managing Hydrology for Channels/Innovative BMPs
Most watershed ordinances throughout the nation focus on TSS management, typically in the range of 70% to 90% to reduce pollutant runoff from a development site. Based on water-quality data, the Highland Lakes are nutrient-limited, with phosphorus as the limiting nutrient. Therefore, the earlier NPS ordinances managed TP with TSS to protect the lakes’ clarity and quality. Since TP includes particulate and dissolved components, it is more difficult to remove from runoff than TSS; thus, a BMP’s type, size, and cost are driven by its ability to treat TP.
The stakeholder process began with a majority of the Lake Travis committee members supporting a TSS, TP, and O&G removal increase to 90% while the Upper Highland Lakes committee firmly believed the pollutant management levels should remain at 70%. This latter committee felt that raising the standards would increase large stormwater management costs and adversely impact economic development.
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| Bioretention with sand overflow under construction
(top) and completed (bottom) |
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Another stakeholder goal was to simplify the ordinance compliance process to reduce cost and time. Staff concurred and, in coordination with JMA, reviewed local bankfull and water-quality data and determined that the one-year storm (1.93 inches in three hours) could serve as a design target to manage channel erosion and water-quality basin design. Using this storm, JMA verified that basins would treat 90% of the annual pollutant load.
Managing for channel erosion can be accomplished by peak flow rate targets through a detention requirement or through volume control to attempt to closely mimic natural hydrologic conditions. Staff was fully aware that effective peak-to-peak detention can be manipulated through hydrologic parameter adjustments to reduce pond size and, in most cases, completely miss the management of frequent storms, which can be the channel-forming storms that do the most stream “work” over time.
Staff felt that volume control was essential in managing the common storm events and channel erosion. To ensure the volume approach was successful, JMA developed a runoff volume relationship based on effective impervious cover percentage. More importantly, by requiring the design storm to be released from basins over a 24- to 40-hour period, discharge resembles natural conditions and eliminates erosive discharges to the receiving water body.
To completely address ordinance fairness, staff believed one ordinance was necessary for the jurisdictional area, not two, due to the similarity of development type and growth patterns. However, a roadblock stood in the path of one ordinance, the stakeholder committee pollutant removal recommendations, 90% for one and 70% for the other.
Behind the stakeholder process scenes, staff coordinated with JMA to develop innovative BMP suites based on runoff volume from the one-year storm, not pollutant loading calculations as prescribed in the previous NPS ordinances. In addition, one storm, not two, would be used to design BMPs, thus meeting the stakeholder’s simplification goal. The BMP suites were composed of numerous options using primary BMPs such as bioretention, extended detention basins, sand filter systems, wet ponds, and wetland basins to treat pollutants and manage runoff volume. Additionally, secondary BMPs such as infiltration trenches, infiltration basins, and vegetated filter strips were available to manage TP and return basin discharges to sheet flow. The BMP suites were established to manage 70% to 75% of the design pollutants (TSS, TP, O&G) by relying on design volume runoff and their expected pollutant treatment performance.
LCRA had the luxury of implementing innovative BMPs through an EPA 319 grant. One BMP example is a bioretention basin combined with a sand filter overflow to achieve a pond depth of 2 feet to reduce the basin footprint and cost. This BMP system can meet the TP removal requirements and does not require a secondary BMP. Another BMP suite that shows great promise is an extended detention basin followed by an infiltration trench. The maximum water depth is 8 feet, thus enabling a small basin surface area. Extended detention minimizes sediment discharge to the infiltration trench and regulates flow to promote design storm infiltration. If runoff discharges from the trench, it will do so in a sheet flow manner to the downstream creek buffer zone, further polishing stormwater runoff.
By taking the runoff volume approach, a project designer would no longer need to compute pollutant loads and calculate 70% or 90% removal. Staff believed the built-in performance based on runoff volume could move the stakeholder discussions toward consensus and get past the 70% or 90% pollutant removal debate.
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| Rainstorm at extended detention basin/infiltration trench best management practice suite |
This concept was presented at the last stakeholder meeting as we summed the total Highland Lakes Watershed Ordinance benefits. Converting to water-quality volume ended the debate on pollutant removal percentages and did not sacrifice water-quality protection. Instead, the two committees realized the benefit of this direction: BMPs would remain similar in size and cost to the previous NPS ordinances, satisfying the Upper Highlands committee. The new buffer zones and education requirements were recognized as worthy additions by the Lake Travis committee to achieve the 90% goal of most committee members. This was the final piece in the stakeholder process to bring the two ordinances to one and move forward to adoption.
Compromise on pollution management targets was achieved through revising the computation approach and providing water-quality volume control to manage channel erosion.
Highland Lakes Watershed Ordinance
The 18-month stakeholder process led to the development of five key performance standards to protect water quality and creek geomorphology. These measures are:
- Pre-development planning for single-family subdivisions greater than 20 acres and commercial tracts larger than 3 acres to guide the development team in planning and designing water-quality protection measures and reducing construction cost
- Manage 70% to 75% of the TSS, TP, and O&G generated by the project and minimize creek degradation by managing the one-year storm design volume in approved BMP suites. Alternate standards are provided for commercial tracts less than 3 acres and development projects with effective impervious cover less than 15%. Incentives for low-impact development include stormwater credits and reduced permitting time and cost.
- Protect creeks and waterways by defining buffer zones when the drainage area exceeds 5 acres. The buffer zones remain free of construction or other alterations except for utility and roadway crossings and low-impact parks.
- Erosion and sedimentation throughout construction is managed by the many BMP options found in the technical manual and consistent with the stormwater pollution prevention plan requirements of the Texas Commission on Environmental Quality.
- Water-quality education is provided annually to neighborhood residents to illustrate the proper use, handling, and disposal of fertilizers, pesticides, herbicides, household chemicals, solid waste, and pet waste.
Lessons Learned
Our experience revealed that successful public participation is more of a negotiated process than a technical process and requires compromise; thus, the committee must have the leadership of technical staff that can communicate water-quality protection to the general public and, most importantly, listen and respond to the committee members’ perspectives. Pepper Morris, Lick Creek resident and stakeholder member, voiced her opinion on the process at the LCRA board meeting: “After fighting for over two years to fix Lick Creek, I have taken to heart the word compromise and appreciate the LCRA stakeholder process to keep us on track, listen, and digest information from the committee. Is the ordinance perfect? Probably not, but our compromises are to be commended to improve water-quality protection.”
By gaining consensus at the committee level with a diverse group of stakeholders, the LCRA Board was not asked to make tough technical decisions. The Highland Lakes Watershed Ordinance process contained many technical aspects, but in the end it was a process about negotiation, information sharing, and deep topic discussions so the diverse stakeholder members could work together to a compromise solution that is more based on science than driven by rhetoric.