Landscape Median Sustainability Conversion

IFB 10907-26
Landscape Median Sustainability Conversion
Attachment A - Scope of Work
General:
This project involves the renovation of designated right-of-way medians to reduce
maintenance and water use.
Site preparation may begin as early as July with planting beginning no earlier than
September 1 and all planting and irrigation work shall be completed by September
30, 2026.
This work is subject to the prevailing wage requirements of the State of Washington.
Please provide pricing per site and activity (site prep, irrigation, plant acquisition and
planting, maintenance). The City intends to award this work to one contractor to the
extent the budget allows.
Work Site Locations:
Site 1 Site 2
West Lake Sammamish Parkway Avondale Road
Includes all medians between SR 520 & Includes all medians between Union Hill
NE 51st St. (6) Road & NE 95th St. (8)
Redmond, WA Redmond, WA
WORK TASKS
Site 1: West Lake Sammamish Parkway medians
Task 1: Site Preparation
* Verify work limits and identify utilities.
* Obtain Right of Way Use Permit and submit traffic control plans per City
standards.
Task 2: Tree and Shrub Removal
* Remove designated trees (including stumps), shrubs, and groundcovers within
the median.
IFB 10907-26 - Attachment A - Scope of Work Page 1 of 4

* Remove all associated root systems that may interfere with new irrigation
installation.
* Haul and properly dispose of all green waste and debris.
* Backfill and compact disturbed areas to pre-existing grade.
Task 3: Irrigation System Replacement
* Remove existing isolation valve at control valve, control valve assembly, pipe,
and heads.
* Reuse existing wire when building new valve assembly (when possible, rebuild
valve assembly in right of way instead of in median).
* Valve assembly shall consist of brass ball isolation valve, Rain Bird EFB-CP Brass
control valve, and schedule 80 unions and fittings on with side of the valve.
* Valve shall be properly sized to provide consistent pressure and flow.
* Pipe shall be schedule 40 and sized to provide consistent pressure and flow.
* 34 in pipe shall be the smallest pipe size allowable.
* Heads shall be Rain Bird SAM PRS 30 12" with a MPR nozzle.
* All connections shall be secured with PVC primer and heavy bodied glue.
Task 4: Planting - Drought-Tolerant Materials
* Scarify and amend soil by incorporating 2-4 inches compost into top 6 - 12
inches of soil.
* Install drought-tolerant trees, shrubs, and groundcovers per table:
Spacing Species Common Name Size
Replace existing Carpinus betulus Frans Fontaine 2-2 12" Caliper
1:1 at 25' o.c. 'Frans Fontaine' European
Hornbeam
5' spacing from Vaccinium ovatum Evergreen 2 Gallon
trees, shrubs, & Huckleberry
curbs.
Triangular planting Echinacea Coneflower 1 Gallon
pattern; 24" purpurea
spacing; in drift Eschscholzia California Poppy 1 Gallon
pattern of 7 or californica
more of single Achillea Yarrow 1 Gallon
species for visual millefolium
impact for passing Carex Testacea Orange sedge 1 Gallon
drivers.
IFB 10907-26 - Attachment A - Scope of Work Page 2 of 4

* Ensure proper spacing, planting depth, and staking of trees.
* Apply 2-3 inches of arbor mulch to planting area to promote moisture
retention and weed suppression avoiding trunks and stems of plant material.
* Water in plant material immediately after installation.
* Provide one-year plant maintenance and warranty
Task 5 Clean-up and Close-out
* Remove construction debris, excess soil, and unused materials from site.
* Leave all hardscape surfaces clean.
* Conduct final walkthrough with project administrator.
* Provide plant and irrigation warranties as required.
Site 2: Avondale Road medians
Task 1: Site Preparation
* Verify work limits and identify utilities.
* Obtain Right of Way Use Permit and submit traffic control plans per City
standards.
Task 2: Shrub and Groundcover Removal
* Remove existing shrubs and groundcover taking care to avoid damage to
existing trees and their roots.
Task 3 Irrigation System Replacement
* Remove existing isolation valve at control valve, control valve assembly, pipe,
and heads.
* Reuse existing wire when building new valve assembly (if possible, rebuild
valve assembly in right of way instead of in median).
* Valve assembly shall consist of brass ball isolation valve, Rain Bird EFB-CP Brass
control valve, and schedule 80 unions and fittings on with side of the valve.
* Valve shall be properly sized to provide consistent pressure and flow.
* Pipe shall be schedule 40 and sized to provide consistent pressure and flow.
* 34 in pipe shall be the smallest pipe size allowable.
* Heads shall be Rain Bird SAM PRS 30 12" with a MPR nozzle.
* All connections shall be secured with PVC primer and heavy bodied glue.
IFB 10907-26 - Attachment A - Scope of Work Page 3 of 4

Task 4: Mulch trees, Prep soil, and Seed
* Use 2-3 inches of arbor mulch to create a ring extending 24" from tree trunk.
* Lightly scarify existing soil surface, taking care to protect roots of trees. Add 2-3
inches topsoil (high organic content, well-draining, no clay). Seed with drought
and shade tolerant low-mow or no-mow mix (PT Lawn Seed 702 'Let it Bee') per
recommended application rates and following planting and care instructions.
* Provide one year turf establishment maintenance and warranty.
Task 5 Clean-up and Close-out
* Remove construction debris, excess soil, and unused materials from site.
* Leave all hardscape surfaces clean.
* Conduct final walkthrough with project administrator.
* Provide plant and irrigation warranties as required.
Deliverables
* As-built irrigation map.
* Plant list with quantities and installation locations.
* Warranty documentation for plant materials and irrigation components.
Contractor Responsibilities:
* Maintain safe work zone conditions in compliance with local regulations.
* Coordinate with City staff where applicable.
* Ensure work meets industry standards and all project specifications.
Work Site Conditions
* At the end of each workday, the site shall be left in a safe condition with the
work sites clean of debris.
IFB 10907-26 - Attachment A - Scope of Work Page 4 of 4