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City of Boerne's News Flash

Posted on: June 27, 2019

Shoreline Park Development Background

Lake

This document was created to provide information regarding the proposed development of Shoreline Park in the extraterritorial jurisdiction area (ETJ) of the City of Boerne. The proposed 100-acre development by KB Homes is part of a 12,500-acre watershed area and represents less than 1% of that area. Neither the city or the county has the power to regulate the density of this development which is planned for 360 homes.

The development will have 19.8 acres of open space and will be served water and wastewater treatment utility services from Kendall West Utilities (KWU). Wastewater will not be treated on site – it will flow via pipeline to the KWU wastewater treatment plant at Tapatio Springs. The property is scheduled to be developed in 3 or more phases. Each will require a preliminary and final plat subject to review and approval by city staff and/or by the Planning and Zoning Commission.

There will be multiple opportunities during the development process to monitor and verify progress on all aspects of the development including drainage and stormwater pollution mitigation. Approximately half of the property will drain toward Boerne City Lake while the other half will drain onto City of Boerne property and eventually to Cibolo Creek.

The engineering and drainage reports for Shoreline Park have been performed by TetraTech Engineering. This firm was recommended by the City of Boerne to the developer (KB Homes) and the same firm provided consulting services for the city’s recent updates to its Low Impact Development (LID) requirements in accordance with San Antonio River Authority (SARA) guidelines. The city hired Jeff Moeller (Moeller & Associates) to review the TetraTech reports and to assist the City with the technical review of both stormwater quality and quantity as it relates to the Shoreline Park development.

Water quantity, quality, and pollution control is of the utmost concern to the city. The design engineer (TetraTech) states in their report that “the proposed development as presented in this master drainage study will not cause any adverse impacts to water quality or quantity downstream of the project”.

This statement applies to water impacts to Boerne City Lake as well as to the Cibolo Creek. Licensed engineers are required to protect the health safety and welfare of the public.  An engineer can lose their license if they sign and seal a plan that has a negative effect on the health, safety and welfare of the public.

Stormwater quality requirements often address the filtration of the “first flush” of stormwater runoff, which is where most pollutants are contained during a rainfall event.  The City of Boerne ordinance applicable to a development near the lake requires the first one-half inch of rainfall runoff to be diverted and treated.  The proposed design also includes buffers between treatment features and streams and lakes that will provide additional, natural filtration to remove additional pollutants.

The City of Boerne requirements for stormwater treatment and buffer zones are equal to or exceed the norms for water quality treatment in most Texas cities. Many cities do not have any requirements (Kerrville and Fredericksburg for example) and Boerne’s requirements are equal to those of much larger cities with adjacency to environmentally sensitive areas such as New Braunfels. Stormwater runoff in that city impacts the Guadalupe River and the Comal River which is home to several endangered species. New Braunfels is also located in the Edwards Aquifer Recharge Zone, and the aquifer is the primary drinking water source for over 2 million people. The City of Boerne’s largest water supply source is Canyon Lake and there are thousands of homes built in close proximity to it with no watershed quality restrictions, LID requirements, or water quality buffers required. 

Matkin-Hoover Engineering has reported on behalf of KB Homes that their preliminary calculations show that the stormwater treatment features planned for Shoreline Park will remove just under 80% of pollutants captured in the first flush that drains to the LID features. In addition, the proposed 300’ natural buffer between the lot lines and the lake, which exceeds City of Boerne and most other city’s surveyed buffer requirements, will remove approximately 60% of whatever pollutants remain for an estimated 92% pollutant removal total. The standard target for total suspended solids (TSS) pollutant removal is 70-80% and this information indicates the Shoreline Park Development will exceed those standards. KB Homes has committed to providing deed restrictions through Conditions, Covenants and Restrictions (CCRs) that will allow for ongoing maintenance and inspection of stormwater pollution features.

The stormwater that does not flow toward Boerne City Lake will be directed to a detention pond and then released. The stormwater will then travel across 2000’ of natural vegetation on city owned property to the Cibolo Creek.

While not required by any ordinance or rule, KB Homes hired geological and environmental consultants Frost Geosciences, Inc. to conduct independent studies of wildlife habitat on the 100-acre site specifically to include Bald Eagle and Golden Cheeked Warbler habitat. The studies determined that there were no areas of concern on the site that would be impacted by development. 

The City is presently drawing samples once a month from 4 locations at the lake and testing for bacteria, pesticide and herbicide levels to establish a baseline for the lake. The 12,500 acres of open space, farm and ranch land and other residential developments in the watershed above the lake all have an impact on pollutants in the lake as do the fish and wildlife within and around the lake itself. The City’s water treatment plant has been functioning well for over 30 years treating the water impounded at the lake and the city has no reason to believe that the Shoreline Park Development will negatively impact the plants proper functioning. The City of Boerne has been recognized with a Superior water supply system designation by TCEQ.

The new precipitation data that was provided recently by NOAA (Atlas 14) impacts stormwater quantity, but not quality.  It has no impact on the city’s current ordinance requirements for LID features which are designed to capture and treat the first ½ inch flush of a storm event, which holds most of the pollutants. Rainfall amounts above that amount is rerouted to not overrun the LID features and is treated by the natural vegetated buffers (300 feet to the lake and 2000 feet to the Cibolo Creek).

Under the Clean Water Act it is unlawful to discharge pollutants from a point source into navigable waters without a permit. This would apply to a commercial/industrial type of development or to a wastewater treatment plant such as the two the city operates. It does not apply to individual homes, farms or ranches unless they are discharging wastewater directly into the lake (like a malfunctioning septic system).

Documents submitted for approval by the Shoreline Park developer were also reviewed by the County Engineer’s office as well as the Kendall County Fire Marshal due to its location outside the city limits. Documents submitted for final plats will include letters/memos of compliance to applicable rules and regulations from all reviewing agencies including the City, Kendall County, Cow Creek Groundwater Conservation District, and Bandera Electric Cooperative.

In summary:

  • The City of Boerne proactively implemented stormwater runoff and pollutant protection ordinances over ten years ago to protect Boerne City Lake, an important water supply and recreational amenity for the citizens of Boerne.
  • The water filtration features proposed for the development meet or exceed all City of Boerne ordinances and standards and are comparable to the standards of other cities in the state and will remove approximately 92% of pollutants that might flow toward the lake, a much higher percentage than is typical in other cities including those with environmentally sensitive areas, creeks, streams and aquifers.
  • Engineering studies state that Boerne City Lake & the Cibolo Creek will not be harmed by pollutants from the Shoreline Park Development due to adherence to those ordinance requirements and the city’s existing rules and regulations.
  • Water quantity, quality, and pollution control is of the utmost concern to the city. The design engineer (TetraTech) states in their report that “the proposed development as presented in this master drainage study will not cause any adverse impacts to water quality or quantity downstream of the project”.

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