HomeMy WebLinkAboutSpecial 2011-05-11 Shoreline Master Program - Color Comparison Matrix - Attachment B: Summary of Buffer WidthsATTACHMENT B
Table3. Summary of Buffer Widths for Land Use Zones and Shoreline Ecological Conditions
Area
Characteristics
Environment
Buffer
Modification
MIC/H & MIC/L
Zoned property
from North City
Limits to EMWS
Bridge, and
North Potential
Annexation Area
Fresh/Salt water
Transition Zone, Lower
flooding risk, Less than
20' difference from
OHWM to top of bank,
tidal influence
High Intensity
100'
The Director may reduce the standard buffer on a
case -by -case basis by up to 50% upon
construction of the following cross section:
- 1. reslope bank from OHWM (not toe) to
be no steeper than 3:1, using bioengineering
techniques
- 2. Minimum 20' buffer landward from top
of bank
- 3. Bank and remaining buffer to be planted
with native species with high habitat value
Comment: Maximum slope is reduced due to
measurement from OHWM and to recognize
location in the Transition Zone where
pronounced tidal influence makes work below
OHWM difficult.
Any buffer reduction proposal must demonstrate
to the satisfaction of the Director that it will not
result in direct, indirect or long -term adverse
impacts to the river. In all cases a buffer
enhancement plan must also be approved and
implemented as a condition of the reduction.
The plan must include using a variety of native
vegetation that improves the functional attributes
of the buffer and provides additional protection
for the shoreline ecological functions.
LDR Zoned
property w/o
levees from
EMWS to 1 -405
Moderate flooding risk,
Less than 25' difference
from OHWM to top of
bank, tidal influence on
northern section
Shoreline
Residential
Distance
required
to set
back
slope
from toe
at 2.5:1
plus 20'
setback,
Min. 50'
width
Removal of invasive species and replanting with
native species of high habitat value voluntary
unless triggered by requirement for a Shoreline
Substantial Development permit
LDR Zoned
property with
levees from
EMWS to 1 -405
Moderate flooding risk,
Less than 25' difference
from OHWM to top of
bank, tidal influence on
northern section
Shoreline
Residential
125'
Upon reconstruction of levee in accordance with
minimum profile, the Director may reduce the
buffer to actual width required.
Comment: this applies to City -owned property at
Fort Dent.
Commercially
zoned property
from 42nd Ave S.
Bridge to 1 -405
Moderate flooding risk,
Less than 25' difference
from OHWM to top of
bank
Urban
Conservancy
100'
The Director may reduce the standard buffer on a
case -by -case basis by up to 50% upon
construction of the following cross section:
• reslope bank from toe to be no steeper
than 2.5:1 using bioengineering
techniques
• Minimum 20' buffer landward from
top of bank
• Bank and remaining buffer to be
planted with native species with high
habitat value
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W:\ \Long Range Projects\ Shoreline\Ecology Review - Adopted SMP\Attachment B -Table 3
04/29/2011 3:50 PM
ATTACHMENT B
Table3. Summary of Buffer Widths for Land Use Zones and Shoreline Ecological Conditions
Area
Characteristics Environment
Buffer
Modification
Any buffer reduction proposal must demonstrate
to the satisfaction of the Director that it will not
result in direct, indirect or long -term adverse
impacts to shoreline ecological functions. In all
cases a buffer enhancement plan must also be
approved and implemented as a condition of the
reduction. The plan must include using a variety
of native vegetation that improves the functional
attributes of the buffer and provides additional
protection for the shoreline ecological functions.
West River bank
from 1 -405 to
South City Limit,
Tukwila 205
Levee and South
Annexation Area
High flooding risk,
Federally certified and
County levee, large
water level fluctuations
Urban
Conservancy
125'
Upon construction or reconstruction of levee in
accordance with City minimum profile the
Director may reduce the buffer to the actual
width required. In no case shall the buffer be less
than 50 feet.
East River bank
without levee
from 1 -405 south
to City Limits
Moderate flooding risk,
20 to 25' difference
from OHWM to top of
bank, Moderate
slumping risk, large
water level fluctuations
Urban
Conservancy
100'
The Director may reduce the standard buffer on a
case -by -case basis by up to 50% upon
construction of the following cross section:
- 1. reslope bank from toe to be no steeper
than 2.5:1, using bioengineering techniques
- 2. Minimum 20' buffer landward from top
of bank
- 3. Bank and remaining buffer to be planted
with native species with high habitat value
Any buffer reduction proposal must demonstrate
to the satisfaction of the Director that it will not
result in direct, indirect or long -term adverse
impacts to shoreline ecological functions. In all
cases a buffer enhancement plan must also be
approved and implemented as a condition of the
reduction. The plan must include using a variety
of native vegetation that improves the functional
attributes of the buffer and provides additional
protection for the shoreline ecological functions.
East River bank
with levee from
1 -405 to South
City Limit
Moderate flooding risk,
20 to 25' difference
from OHWM to top of
bank, Moderate
slumping risk, large
water level fluctuations
Urban
Conservancy
125'
Upon reconstruction of levee in accordance with
City minimum profile the Director may reduce
the buffer to the actual width required for the
levee. In no case shall the buffer be less than 50
feet.
Any shoreline
environment
where street or
road runs parallel
to the river
through the
buffer
End buffer on river side of existing improved
street or roadway.
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W:\ \Long Range Projects \Shoreline\Ecology Review - Adopted SMP\Attachment B -Table 3
04/29/2011 3:50 PM