1-22-24 Workshop handout - E. GlasserW OV k"Y NU3V t -\Uv uw k - u 1U
Addressing Community Concerns: Impervious Surface Ration (ISR)
January 2024
City 2040 Vision:
"In Atlantic Beach, we have a sense of belonging and safety. Our citizens and government care deeply about community
character, and we understand that unified support is required to preserve it. We are graced with the functional beauty
of our beach, our marsh, and our tree canopy. Our shady streets and multi -use paths connect our welcoming
neighborhoods and vibrant local businesses. Our city supports our diverse, multigenerational, socially linked community
with green spaces, active lifestyles, parks, and programming." (Adopted 2022)
Key Recommendations
• Commit to not allow additional impervious surface with new development
and redevelopment.
• Consider both quantity and quality of stormwater runoff.
• Return the ISR to 35% for residential development.
• Provide science -based credits for permeable materials, trees, and green
space.
• Maintain compliance through greater enforcement.
AB Preservation (ABP) Observations:
1. ABP met with city staff in December 2023 to convey that the impervious surface
ratio (ISR) for residential lot coverage is an issue of community concern.
2. ABP supported the reduction of the ISR in 2019, but ABP urged that it be
lowered even more.
3. More impervious surface means more stormwater run-off.
4. ABP is open to allowing credits for tested permeable materials.
5. A timeline for historical changes in ISR is attached.
6. Property values did not suffer as a result of slightly lowering the ISR in 2019. In
fact, they increased more than neighboring cities.
7. Overdevelopment is inconsistent with our Comprehensive Plan and 2040
Vision.
8. Redevelopment and new development have increased both quantity and quality
(pollutants) of stormwater runoff.
9. ISR modeling in the core city with the last stormwater master plan update
demonstrated that the higher the ISR, the more stormwater run-off to manage.
10. AB's onsite storage requirement was designed to manage current and additional
impervious lot coverage, but it can fail due to lack of maintenance and
challenges to enforce.
11. The amount of allowable lot coverage has resulted in visible changes to the look
and feel of AB.
12. The greatest impact of the ISR for lot coverage is in residential zoning districts.
13. Much of our infrastructure functioned for a lower ISR. Notwithstanding age and
maintenance, infrastructure costs to build and manage higher volumes of
stormwater will be more costly and would be directly proportional to the ISR.
14.AB is losing old growth tree canopy due to clearing of lots for overdevelopment.
15. Relying on existing setbacks for adequate controls of maximum lot coverage is
inadequate.
16. Our residents value a small-town quality of life, natural beauty, green spaces,
and tree canopy. All are impacted by overdevelopment.
17. Managing surface lot coverage for stormwater runoff does not mitigate all
flooding in low lying areas or prevent the impact of sea level rise.
18. Paver and driveway installations in violation of the ISR often avoid enforcement.
Cheating is not a reason to allow more impervious surface.
Other Recommendations
1. Any code changes should be driven by data and science, as well as concerns for
protecting the natural beauty and character of our city.
2. Defer on code changes related to ISR and stormwater management without a city-
wide stormwater master plan update that includes ISR surface modeling for all
parts of the city, including the Marshside.
3. Discussion on proposed zones should be part of robust and transparent
community engagement.
4. Do not increase ISR in commercial zoning districts and consider possible code
changes to address size limitations, with credits for permeable materials, green
space, and trees.
5. ABP supports the existing requirement for on-site storage.
6. Require homeowners to submit onsite drainage plans from an engineer for any
development or redevelopment.
7. Require homeowners to submit an engineer's certification of the total impervious
surface, including pavers and pools that may receive credits.
8. Setbacks should be reviewed for viability to manage ISR lot coverage.
9. Grandfathering should be limited to current owners but not for redevelopment and
teardowns.
10. Properly laid permeable pavers can be considered for credit according to the type.
As part of the permitting process, a check by the building department should be
made to assure proper installation.
11. Swimming pools could be considered 50% pervious. Infinity pools should be
considered 100% impervious.
12. Treat artificial turf as impervious, except with conditions to be proposed by staff.
13. New city sidewalks and hardscape should employ pervious materials as much as
possible.
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REFERENCES
https://buildgreen.ifas.ufl.edu/Fact_sheet_Permeable_Surfaces.pdf
https://pinehalIbrick.com/florida-towns-permeable-paver-installation-wins-national-
recognition/
https://gsi.floridadep.gov/paIatka-permeable-paving-improvements/
https://blogs. ifas.ufl.edu/escambiaco/2021 /02/23/weekly-what-is-it-pervious-pavement/
https://www.oriando.gov/files/sharedassets/public/v/1 /departments/edv/city-
planning/ldc2021-10008-artificial-turf-and-landscape-code-amendment. pdf
https://www.nytimes.com/wirecutter/reviews/best-artificial-grass/
https://www.coralgables.com/sites/defauIt/files/mediaexport/City%20Managers/Administ
rative%20and%201mpie menti ng%20Orders/10%202019-
01 %20Artificial%20Turf Amended.pdf
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Impervious Surface Ratio (ISR) Lot Coverage Timeline
1982: (Ordinance 90-82-74)
Impervious Surface was included in the definition for Lot Coverage. Lot Coverage
included all areas of the lot covered by principal and accessory uses and structures as
well as impervious surfaces such as drives, parking areas, walkways, swimming pools,
patios, terraces, and the like.
• The maximum lot coverage for all residential districts was 35%.
• The maximum lot coverage for Commercial Limited (CL) was 65%.
• There was no maximum lot coverage for Commercial General (CG), Commercial
Intensive (CI) and Light Industrial (LIW).
1985: (Ordinance 90-85-91)
Impervious surfaces such as drives, parking areas, walkways, swimming pools, terraces,
and the like were removed from the lot coverage definition, and thus, the maximum lot
coverage restrictions. This change was due to the parking requirements at the time (off
street parking not allowed in front setbacks) which made it nearly impossible to meet the
maximum 35% lot coverage requirement. As a result, maximum lot coverage only
accounted for areas of the lot covered by principal and accessory uses and structures.
• The maximum lot coverage for all residential districts 35%
• The maximum lot coverage for CL was 65%
• There was no maximum lot coverage for CG, Cl, and LIW
1986: (Ordinance 90-86-113)
The City eliminated maximum lot coverage requirements in all residential zoning districts,
meaning no restrictions for maximum lot coverage existed at this time. It was mentioned
by the City Commission that the 35% maximum lot coverage requirement was
unnecessary due to new setback requirements that allowed for over 35% lot coverage.
The belief was that setback requirements would serve to control the amount of a lot
covered by structures. Also, no definition or restrictions on impervious surfaces existed in
the City Code at this time.
1998: (Ordinance 90-98-167)
Due to flooding and storm water concerns, impervious surfaces such as driveways,
patios, decks, and the like were added to the definition of lot coverage. Additionally, a
50% maximum lot coverage requirement was created for all residential zoning districts.
• The maximum lot coverage for all residential districts was now 50%
• No lot coverage requirements existed for commercial and industrial properties.
2001: (Ordinance 90-01-172)
An independent definition of impervious surface was added to the City Code. This
definition included rooftops, sidewalks, patios, driveways, parking lots, and similar
surfaces. Swimming pools were not considered impervious because of their ability to
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retain additional rain water. The definition of lot coverage was changed to "the area of the
lot covered by all impervious surfaces."
Also added 70% maximum Impervious Surface restrictions for CBD, CL, CG, and LIW
zoning districts and 25% maximum Impervious Surface restriction for the Conservation
zoning district.
• The maximum Impervious Surface for Conservation zoning was 25%
• The maximum Impervious Surface for residential districts was 50%
• The maximum Impervious Surface for commercial and industrial zoning districts
was 70%
2003: (Ordinance 90-03-184)
Added "surfaces using pervious concrete or other similar open grid paving systems shall
be calculated as 50% impervious" to definition of impervious surface due to
advancements in paver and pervious concrete technology. Lot coverage was still defined
as the area covered by all impervious surfaces.
• The maximum Impervious Surface for Conservation zoning was 25%
• The maximum Impervious Surface for residential districts was 50%
• The maximum Impervious Surface for commercial and industrial zoning districts
was 70%. Except that maximum Impervious Surface did not apply to infill
development or redevelopment of previously developed sites; however,
landscaping was required in accordance with the City Code. Stormwater
management requirements were also required for infill development and to
redevelopment projects involving exterior site changes.
2006: (Ordinance 90-06-188,)
Due to pavers often being installed in a way that prevented permeability, the following
language was added to the definition of Impervious Surface:
"Open grid pavers must be installed on a sand base, without liner, in order to be
considered 50% impervious. Solid surface pavers do not qualify for any reduction in
impervious area, regardless of type of base material used."
In order to address infill and redevelopment of residential lots, the language below was
also added to the definition of Impervious Surface:
"In such cases where a previously and lawfully developed residential lot or development
project exceeds the 50% limit, redevelopment or additions to existing residential
development shall not exceed the pre -construction Impervious Surface limit..."
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