Item 6HItem 6H
Amendments to Ordinance No. 480 to add regulations for streamway buffer and permeable pavement (Ord. 480-VVVV)
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Purpose of the Amendments
Add development regulations for the buffering of natural areas along steams
2. Miscellaneous zoning corrections (Yard Sale, RE District)
3. Add development regulations for the use
of permeable pavers (3 options – Option #1 – Incentivize, Option #2 – Mandatory, Option #3 – Mandatory + Incentive
There are 3 components to the amendment
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Proposed Amendment to Ord. No. 480
Allow bufferyard credit on property boundary containing buffer or on boundaries parallel to the buffer
Allow 1 for 1 tree credit for saving native trees within the buffer
Area measured 25ft from top of bank or 50ft from the creek centerline
No disturbance within stream buffer except for uses allowed in bufferyards
A redline ordinance is provided in your packet. Affected sections of Ord. 480 are section 4, Definitions and section 42, Bufferyards.
Key components of the ordinance:
- Definition
of streambuffer as 25 feet from top of bank, 50 feet from creek centerline or limits of 100 year floodplain. No disturbance would be allowed in those areas.
Only uses that are permitted
in the streambuffer are the same uses allowed in manmade bufferyards as defined in section 42 which is limited mostly to primitive trails and footpaths.
The Streambuffer required to
be placed in a conservation easement or made a separate deed-restricted tract in a larger development. Clearing is only allowed in case of imminent threat to life or property, or in
cases where an invasive species is cleared out and replaced with native species.
Implementation of a streambuffer would be developer option under the proposed ordinance and again can
only be approved by City Council.
The ordinance is incentive-based and grants City Council the ability to allow 1 to 1 credits on new interior and bufferyard plantings when existing
trees in the buffer exceed the required bufferyard plantings for the bufferyard which is being waived.)
Streambuffer and existing trees must be catalogued in a Tree Conservation Plan.
Minimum amount of tree canopy must still be preserved based on existing coverage (landscaping ordinance 585-D is not proposed to be amended at this time.)
For sites with a stream running
diagonally or meandering through the site, 50% bufferyard credits may be given for required bufferyards on each side or parallel to the stream. The credits would apply to width and plantings.
Screening with fence, wall, or hedge would still be required.
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STREAM ON PROPERTY BOUNDARY
Off-street parking
Building
Building
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STREAM INTERIOR TO SITE
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Section 4 and Section 34 do not agree on number of garage sales allowed
Amendment Details – Garage Sales
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Section 4 and Section 34 do not agree on number of garage sales allowed
Amendment Details – Garage Sales
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Proposed Amendment to Section 45 to add “RE-5” and “RE-7” in place of former “RE” district
Ord. 480-UUUU was approved in June and established the RE-5 (formerly RE) and RE-7 zoning districts. This amendment would update two instances in Section 45 that were missed with Ord.
480-UUUU.
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Summarize Sustainability Plan which combined components of various plans including environmental protection, water, stormwater, transportation, and fiscal responsibility. The term “sustainability”
means meeting present needs without compromising the needs of future generations. The term was first used in the VGOs of the Southlake 2030 plan.
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Cost Evaluation - Concrete
Conventional - $12.08/sq ft Porous - $16.85/sq ft
Conventional - $12.08
Porous - $16.85
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Cost Evaluation - Asphalt
Conventional - $8.88/sq ft Porous - $9.74/sq ft
Conventional - $12.08
Porous - $16.85
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Cost Evaluation - Pavers
Conventional - $12.08/sq ft Pavers - $21.43/sq ft
Conventional - $12.08
Porous - $16.85
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Option #1 - Proposed Amendment to Ord. No. 480
INCENTIVIZED OPTION: Permeable Concrete and Asphalt may be used to offset stormwater utility fees.
Definition added for permeable pavement.
Permeable pavers may be approved on a case by case basis.
Based on 8-2 City Council work session feedback, Staff was directed to develop two options: An incentivized approach to implementing permeable pavement and a required approach.
Incentivized:
stormwater utility fees assessed by calculating impervious coverage. This ordinance would allow sites using permeable pavement to reduce impervious coverage calculations by 50% for any
area with permeable pavement.
A definition would also be added which outlines minimum requirements for a surface to be considered permeable pavement.
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Option #2 - Proposed Amendment to Ord. No. 480
REQUIRED OPTION: 20% of all off-street parking areas required to be permeable on sites or developments that are larger than 1 acre.
Permeable pavers may be approved on a case by case basis.
Ordinance may be revisited in the future to consider adjusting percentage.
Based on 8-2 City Council work session feedback, Staff was directed to develop two options: An incentivized approach to implementing permeable pavement and an approach which makes use
of permeable pavement a requirement.
Required: All sites or portions of a development over 1 acre would be required to pave at least 20% of off street parking areas using permeable
pavement. (Based on language in the Sustainability Plan and iSWM.)
A definition would also be added with both options which outlines the minimum requirements for a surface to be considered
permeable pavement. (Engineered, maintenance plan, letter of certification at C.O.)
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Proposed Amendment to Ord. No. 480
HYBRID OPTION: 20% of all off-street parking areas required to be permeable on sites or developments that are larger than 1 acre.
Any use of permeable pavement above base required amount qualifies for incentive.
Based on 8-2 City Council work session feedback, Staff was directed to develop two options: An incentivized approach to implementing permeable pavement and an approach which makes use
of permeable pavement a requirement.
Required: All sites or portions of a development over 1 acre would be required to pave at least 20% of off street parking areas using permeable
pavement. (Based on language in the Sustainability Plan and iSWM.)
A definition would also be added with both options which outlines the minimum requirements for a surface to be considered
permeable pavement. (Engineered, maintenance plan, letter of certification at C.O.)
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Reduces surface temperatures by absorbing more heat than impervious paving;
Reduces pooling of water during rain events
Permeable Pavement can reduce the amount of surface pollution which is typically carried by rain events within the first few minutes. It transfers these pollutants to the soil where
they are filtered before entering ground water.
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Proposed Amendment to Ord. No. 480
The City utilizes pervious pavers in off-street parking areas at its DPS North facility, completed in 2015.
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Porous Concrete
Wal-Mart on Redbud Rd
McKinney, TX
The City utilizes pervious pavers in off-street parking areas at its DPS North facility, completed in 2015.
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Porous Asphalt
The City utilizes pervious pavers in off-street parking areas at its DPS North facility, completed in 2015.
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Questions?
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STAFF RECOMMENDATION -
CC 1st Reading
October 4, 2016; Approved 4-0, noting that the recommendation of mandatory versus incentivized use of permeable material, Council is not making a recommendation rather is directing staff
to provide options and clarity at 2nd reading as it relates to no requirement with incentives, a requirement plus incentives and any new options to address concerns regarding the feasibility
of implementing the process. Also noting that in terms of garage sales, Council is allowing a maximum of two (2) per year per address and specifically noting that all other changes proposed
in this ordinance are approved at 1st reading. Also noting that related to the creek setback regulations that it will be the greater of 25 feet or 50 from the centerline of the creek.
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Permeable vs. Conventional Surfaces
* Installed costs accounts for associated drainage structures, base aggregate costs, and 20% multiplier, but does not account for maintenance or any land value factors.
Proper installation requires soil survey, base aggregate layers which allow for stability and water storage. Initial costs may be balanced out by a reduction or elimination in the need
for on-site detention, which frees land for other uses.
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Permeable vs. Conventional Surfaces
* Installed costs accounts for associated drainage structures, base aggregate costs, and 20% multiplier, but does not account for maintenance or any land value factors.
Wide range of prices reflects the range of studies, applications, intended uses and type of materials.
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Sustainability Master Plan
Use of permeable pavement is Key Recommendation WR4 in the Water Resources section of the Sustainability Plan.
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Amendment Details – Creek Buffer
A Tier 1 recommendation of the 2015 Sustainability Master Plan is the implementation of a stream/creek/ floodplain buffer.
The intention of the buffer is to reduce erosion, preserve
habitat, increase open space, and minimize impacts from site development and increases in impervious coverage.
The development of a buffer to protect streambanks from development was identified in the Sustainability Plan as a tier 1 recommendation, intended to be implemented within 1 to 3 years.
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Benefits of Creek Buffer
Can be used as nonstructural stormwater filtering and infiltration zones;
Keeps structures out of the floodplain and provides a right-of-way for large flood events;
Streambuffers take advantage of the natural filtering characteristics of the soil to slow and filter stormwater runoff. Trees and vegetation along the stream bank stabilize it against
erosion.
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Benefits of Creek Buffer
Helps to preserve riparian ecosystems and habitats. (From iSWM Technical Manual, rev. 9/14)
Maintaining the buffer helps prevent the displacement of wildlife that is common in developing areas.
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Sustainability Master Plan – Water Resources
“(S)imply providing a buffer area adjacent to streams, creeks, and floodplains can protect water quality by allowing the ecosystem to naturally collect and treat pollutants in runoff
before they reach surface waters. Buffer areas can also reduce erosion, preserve habitat, increase open space, and reduce flooding.”
- Pg. 18
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Sustainability Master Plan – Goals and Objectives
Addition of a streambuffer ordinance would fulfill two objectives:
Manage runoff and contamination of streams and groundwater.
Conserve additional tree cover.
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Sustainability Master Plan – Built and Natural Environment
Pg. 39
The Sustainability Plan makes protecting trees and stream corridors a policy initiative with direction to consider restricting development within a minimum distance of the buffer.
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Sustainability Master Plan Water Resources Recommendations
A streambuffer ordinance is recommendation WR1 in the Water Resources section with a direction to consider codifying the use of streambuffers in the City Code.
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iSWM
The adopted Integrated Stormwater Management (iSWM) Manual assists cities in meeting TCEQ stormwater requirements, in part by preserving certain natural site features conducive to abatement.
A streambuffer is also described as a Best Management Practice in the Integrated Stormwater Management Technical Manual developed by COG and adopted by the City. It is currently a tool
that the City can implement to manage runoff and bank erosion, but streambank characteristics are not defined within City Code and there is no mechanism to encourage their use.
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iSWM
Preservation and conservation of existing stream and riparian areas within a site listed as “Integrated Site Design Practice”s in the iSWM Technical Manual.
A streambuffer is also described as a Best Management Practice in the Integrated Stormwater Management Technical Manual developed by COG and adopted by the City. It is currently a tool
that the City can implement to manage runoff and bank erosion, but streambank characteristics are not defined within City Code and there is no mechanism to encourage their use.
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Sustainability Master Plan Water Resources Recommendations
Implementing iSWM is also a Key Recommendation of the Sustainability Plan.
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Typical Creek Buffer Profile
(From iSWM Technical Manual, rev. 9/14)
iSWM defines the typical creekbuffer profile. The first 25 feet from streambank are most critical in protecting the stream, though protection further out can also provide benefits.
An
effective buffer also restricts development with in the 100 year floodplain. If the 100 FP boundaries exceed the minimum for the standard buffer, the 100 FP boundaries should be the
limit of development.
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Option 1 – Amend Section 4
GARAGE SALES – Occasional sales (garage sales and patio sales only) at retail, not to exceed two (2) three (3) in number on the same premises in any one calendar year, by a person who
does not hold himself out as engaging in, or does not habitually engage in, the business of selling such property at retail; provided that (1) the sale shall be confined to the garage
and/or patio of the premises; (2) no new merchandise acquired solely for the purpose of resale on the premises shall be sold at such occasional sale; (3) the duration of each such sale
shall not exceed three (3) consecutive calendar days; (4) a permit shall be secured at least 72 hours prior to and shall be prominently posted on such premises during such sale; (5)
the permit fee amount shall be as established by the City Council; (6) only one sign shall be permitted, not to exceed two (2) square feet in area, upon the premises where and when the
sale is taking place. All other signs relating to the sale, either on or off the premises, shall meet the requirements of all sign regulations adopted by the City.
The First option would amend Section 4 to allow three garage sales per year in accordance with Section 34, accessory uses.
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Option 2 - Amend Section 34
The Second option would amend Section 34 to allow 2 garage sales per year in accordance with Section 4.
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PZ Action
August 18, 2016; Voted 4-0 to recommend approval, noting that both options for the paving will go to Council, further noting P&Z's recommendation with respect to the number of garage
sales allowed within section 4, Definitions and section 34, Accessory Uses be two allowed per year and not three, and approving the final component of the amendment.
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