HomeMy WebLinkAboutApproved - Wetland Mitigation Plan September 26, 2014
AOA 4540
Rocale Timmons
City of Renton - Current Planning
Senior Planner
1055 South Grady Way
Renton, WA 98057
rtimmons@rentonwa.gov
REFERENCE: Whitman Court PUD
SUBJECT: Monitoring and Maintenance Plan for Buffer Enhancement
Dear Rocale,
Following is the monitoring and maintenance plan from the drawings in report form.
PART 1: BACKGROUND
Scope of this plan includes portions within Tract A including the trail, fence and plant
installation as depicted on this approved plan set (Final Buffer Enhancement Plan) dated
9/26/14. Areas outside of the planting locations are not covered under this plan and are
part of the previously approved NGPA for the Ribera Balko Short Plat recorded on
4/9/2009.
PART 2: FINAL ACCEPTANCE
Upon completion of the planting, the Landscape Contractor shall provide AOA with a set
of clearly marked prints designating the actual locations and quantities of plantings within
the mitigation areas. Landscape Contractor shall keep a complete set of prints at the job
site during construction for the purpose of "red-lining" changes or modifications to the
approved plans and shall update said information on a daily basis.
AOA shall approve planting locations. If items are to be corrected, a punch list shall be
prepared by AOA and submitted to the Landscape Contractor for completion. After
punch list items have been completed, AOA shall review the project for final acceptance
of plan implementation. After acceptance has been obtained, Landscape Contractor shall
provide as-built drawings to AOA of planted material.
AOA shall visit the site upon completion of mitigation plan implementation and provide
the City of Renton with written confirmation that installation complies with this plan. If
AOA is unable to provide the City of Renton with such verification, an as-built wetland
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September 26, 2014
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mitigation plan shall be prepared by AOA and submitted to the City for review and
approval.
The date the City of Renton receives AOA written confirmation of installation pursuant to
the final approved mitigation plan, they shall constitute beginning of the 5-year
maintenance and monitoring period.
PART 3: ONE-YEAR WARRANTEE MAINTENANCE
As part of the construction budget for the project, the landscape contractor shall maintain
the mitigation work during construction and for a period of one-year after construction.
Maintenance shall be conducted according to Section 4 below and pursuant to Renton
Municipal Code to clearly ensure that structures, improvements and mitigation perform
satisfactorily for a period of 5 years.
After warrantee replacements are completed by the Landscape Contractor, the remaining
4 years of maintenance shall be completed as part of the long-term maintenance and
monitoring budget.
PART 4: LONG-TERM MONITORING & MAINTENANCE SCHEDULE
The monitoring and maintenance program will be conducted for a period of five years,
with quarterly reports submitted to the City of Renton for the first year after construction
acceptance and annual reports submitted for Years 2-5.
Although the entire mitigation area will be reviewed, permanent vegetation sampling
plots will be established at selected locations to incorporate all of the representative plant
communities. The same monitoring points will be re-visited each year with a record kept
of all plant species found. Vegetation will be recorded on the basis of relative percent
cover of the dominant species within the vegetative strata.
Photo-points will be established from which photographs will be taken throughout the
monitoring period. These photographs will document general appearance and progress
in plant community establishment in the enhancement area. Review of the photos over
time will provide a visual representation of success of the mitigation plan.
PART 5: GOAL, OBJECTIVES AND PERFORMANCE STANDARDS FOR MONITORING
The primary goal of the mitigation plan is to increase the buffer functions over current
conditions. To meet this goal, the following objectives and performance standards have
been incorporated into the design of the plan:
5.1 - OBJECTIVE A
Increase the structural and plant species diversity within the mitigation area.
5.2 - PERFORMANCE STANDARD FOR OBJECTIVE A
Following every monitoring event for a period of at least five years, the mitigation area
will contain at least 8 native plant species. Following each monitoring event, there will
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be at least an 80% survival rate of all initially planted tree and shrub species or equivalent
replacement of a combination of planted and re-colonized native species.
5.3 - OBJECTIVE B
Limit the amount of invasive and exotic species within the mitigation area.
5.4 - PERFORMANCE STANDARD FOR OBJECTIVE B
After construction and following every monitoring event for a period of at least five
years, exotic and invasive plant species will be maintained at levels below 15% total
cover in all planted areas. These species include, but are not limited to, Scot's broom,
Himalayan and evergreen blackberry, reed canarygrass, morning glory, Japanese
knotweed, English ivy, thistle, and creeping nightshade.
PART 6: LONG-TERM MAINTENANCE SPECIFICATIONS
Maintenance will be conducted on a routine, year round basis. Additional maintenance
needs will be identified and addressed following a twice-yearly maintenance review.
Contingency measures and remedial action on the site shall be implemented on an as-
needed basis at the direction of the wetland consultant or the owner.
6.1 - WEED CONTROL
Routine removal and control of non-native and other invasive plants (e.g., Scot's broom,
reed canarygrass, Himalayan and evergreen blackberry, Japanese knotweed, English ivy,
morning glory, thistle and creeping nightshade) shall be performed by manual means.
6.2 - IRRIGATION
The owner shall ensure that all plants are irrigated from June 1 through October 31.
During the first year after installation, irrigation should occur at a rate of 1/2" of water
two to three times a week. During the second year after installation, irrigation should
occur at a rate of 1/2" of water once a week. However, if more than 10% of plant
replacement occurs, watering rates should be maintained at 1/2" of water twice a week.
6.3 - MAINTENANCE OF TREES
Routine maintenance of planted trees shall be performed. Measures include resetting
plants to proper grades and upright positions. Tall grasses shall be weeded at the base of
plants to prevent engulfment. Weed control should be performed by; hand removal,
installation of weed barrier cloth with mulch rings, or selective weed-whacking. If weed-
whacking is performed, great care shall be taken to prevent damage to desired native
species either planted or re-colonized.
6.4 - PRUNING OF WOODY PLANTS
Woody plants shall only be pruned at the direction of the wetland consultant or to
remove pest infestations (i.e., tent caterpillar).
PART 7: CONTINGENCY PLAN
All dead plants will be replaced with the same species or an approved substitute species
that meets the goal of the mitigation plan. Plant material shall meet the same
specifications as originally-installed material. Replanting will not occur until after reason
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September 26, 2014
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for failure has been identified (e.g., moisture regime, poor plant stock, disease, shade/sun
conditions, wildlife damage, etc.). Replanting shall be completed under the direction of
the wetland consultant, City of Renton, or the owner.
If you have any questions, please contact me at (425) 333-4535 or email me at
simone@altoliver.com.
Sincerely,
ALTMANN OLIVER ASSOCIATES, LLC
Simone Oliver, LA
Project Manager
cc via email: Paul Ebensteiner