West Point Treatment Plant

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WHAT’S THE PROJECT? West Point Treatment Plant

King County is updating the underground Water Reservoir Facility West Point Treatment Plant serves more than 700,000 people. at Discovery Park. We are committed to protecting public health Treats wastewater from homes and businesses in Seattle, Shoreline, north and promoting a healthy environment. Lake Washington, north King County and parts of south Snohomish County. The treatment plant was built in 1966. The reservoir was built around the The facility has two reservoirs of drinkable and process water. Drinking water is used at

FAST FACTS FAST same time. West Point Treatment Plant, the lighthouse and drinking fountains in the park. Process water is used for industrial purposes at the treatment plant. The project will upgrade the facility to meet current standards and allow safe and efﬁcient access for annual inspections required NORTH BEACH TRAIL by Seattle Public Utilities. Installing a 460-foot pipe from the reservoir to a discharge site will keep overﬂows away from the treatment plant and other populated areas. LOOP TRAIL West Point DISCOVERY PARK BLVD. This project protects water sources and equipment. Treatment

Evacuation assembly area Plant Inplant assembly area Emergency exit Puget Sound Evacuation route rail Parking T

Rest rooms each Picnic area th B Nor Roads Trails Secondary clarifier DISCOVERY PARK BLVD. LOOP TRAIL (LOWER)

Wetland

Administration Building LOOP TRAIL (UPPER) TRAIL LOOP

WETLAND ifiers NORTH BEACH Clar Light

house HIDDEN VALLEY TRAIL

Hidden Valley Trail l

i SOUTH BEACH TRAIL

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Oxygen Generation Building T

West East d primary a

primary o Water Reservoir

treatment Maintenance s

treatment s e

Building c DISCOVERY PARK c A Facility and Solids Treatment Planned Building Access Road CAPEHART TRAIL Elliott Bay SOUTH Upgrades BEACH Multiuse Building

D isc (acc o ver Main entrance ess r y P ar oad) k B lv Main entrance d 1301_3069_WPTreatmentPlantMap.ai

LOOP TRAIL

Water Reservoir Facility Plan

Department of Natural Resources and Parks Wastewater Treatment Division

1901_9468a _Discovery_Park_Meeting_BOARD1.ai WHEN AND WHERE West Point Treatment Plant ARE WE WORKING?

SCHEDULE Construction begins Summer 2019 and will take three to ﬁve months. We’ll wrap up in Fall 2019. APPROX. OUTFALL WHAT YOU WILL SEE WORK AREA

Construction will take place at an existing CAPEHART TRAIL reservoir near Loop Trail. A pipe will be

DISCOVERY PARK BLVD. installed from the reservoir and run southeast, 5 TEMPORARY through the new Capehart Trail, to a discharge DETOUR TRAIL 4 site with ballast rock. (non-ADA accessible) 3 WHAT YOU WILL NOTICE 7 6 • Affected section of Loop Trail is 0.2 miles, 2 LOOP TRAIL from Discovery Park Blvd to reservoir. LOOP TRAIL (UPPER) • This section of Loop Trail will remain open to trail users, but will also be accessed

by construction vehicles escorted by C1-C2 RESERVOIR LOOP TRAIL (LOWER) ﬂaggers on foot. 1 LEGEND KEY NOTES 1 • Section of Loop Trail may be PEDESTRIAN TRIPS ON LOOP TRAIL ARE TO BE ACCOMPANIED BY FLAGGERS IN FRONT AND BACK OF TRUCK ON TRAIL ONLY THE ACCESS ROUTES SHALL BE KEPT TO A MINIMUM BY IDENTIFYING THE NECESSARY WORK AND intermittently closed during heavy PEDESTRIAN / EQUIPMENT NEEDED TO COMPLETE THE ACTIVITIES PLANNED WITHIN THE PROJECT BOUNDARY. CONSTRUCTION DIFFUSER PIPE ACCESS construction vehicle use. WORK AREA 2 UPPER LOOP TRAIL IS NOT TO BE USED FOR CONSTRUCTION ACCESS OR ACTIVITY. THIS TRAIL WILL BE PHASED OUT BY SEATTLE PARKS PRIOR TO THE RESERVOIR PROJECT. (NEW) LOOP TRAIL • A section of Capehart Trail will be 3 EXISTING UNOFFICIAL FOOTPATH, NON-ADA ACCESSIBLE. NOT TO BE USED AS OFFICIAL DETOUR. 4 PHASE WORK IN OUTFALL WORK AREA TO MAINTAIN PEDESTRIAN ACCESS TO THE EXISTING temporarily closed and contractors CAPEHART TRAIL TO THE GREATEST EXTENT POSSIBLE. INSTALL TEMPORARY PEDESTRIAN TRAIL DURING TRENCHING ACROSS THE CAPEHART TRAIL PER DETAIL 1 ON C001.

will create a detour. 5 RESTORE OUTFALL WORK AREA AND CAPEHART TRAIL TO EXISTING CONDITIONS PER RESTORATION PLANS AND SPECIFICATIONS. TO PLANT • Demolition of concrete hatches 6 TEMPORARY CONSTRUCTION ACCESS PER DWG G104, NOT TO CONFLICT WITH, OR BLOCK, LOOP TRAIL. LOOP TRAIL 7 EXISTING STOCK PILE AREA FROM CAPEHART TRAIL CONSTRUCTION TO BE UTILIZED FOR RESERVOIR AND DIFFUSER CONSTRUCTION STAGING. AREA IS APPROXIMATELY 2600 S.F. FIELD VERIFY BOUNDARY on top of reservoir. LOOP TRAIL FROM STAKED LIMITS. • Removal of trees and vegetation. • Excavation and trenching. (EXISTING) BELOW-GRADE RESERVOIR WORK AREA

SOUTH BEACH TRAIL Department of Natural Resources and Parks 100 FT Wastewater Treatment Division

1901_9468a _Discovery_Park_Meeting_BOARD2.ai TREE REMOVAL AND PROTECTION West Point Treatment Plant

Impact on trees TREES RECOMMENDED FOR REMOVAL Tree ID DBH Tree Species Common Na me Approximately 26 trees are recommended for removal. We are committed to replacing two trees for every Number (Inches) one tree removed, per the City of Seattle’s requirement. 19 of the 26 trees identiﬁed are under 6 inches 1 Pinus contorta Lodgepole pine 4 in diameter. The remaining trees are larger and vary in size, up to a 25-inch red alder. Tree species 2 Prunus emarginata Bitter cherry <1-5 recommended for protection include lodgepole pine, Oregon ash, bitter cherry, and bigleaf maple. 3 Prunus emarginata Bitter cherry <1-6 4 Pseudotsuga menziesii Douglas fir <1 LEGEND 5 Acer circinatum Vine maple 2 Trees over 6 inches 6 Prunus emarginata Bitter cherry <1-6 in Diameter at Breast Height (DBH)* 7 Pinus contorta Lodgepole pine 1 C1/C2 8 Pinus contorta Lodgepole pine 2 BELOW Trees under 6 inches GROUND in Diameter at Breast 9 Pinus contorta Lodgepole pine 1 RESERVOIR Height (DBH)* 10 Pinus contorta Lodgepole pine 1 1 Tree ID number 11 Pinus contorta Lodgepole pine 1 MEADOW AREA Project Area 12 Pinus contorta Lodgepole pine 1

1+ 00 13 Pinus contorta Lodgepole pine 2 460-foot long HDPE underground pipe 14 Pinus contorta Lodgepole pine 1.5 1 PINUS CONTORTA 15 Pinus contorta Lodgepole pine 1 PRUNUS EMARGINATA 4 PSEUDOTSUGA MENZIESII 2 2+ 0 PRUNUS EMARGINATA3 5 ACER CIRCINATUM 0 15 30 60 16 Crataegus monogyna Oneseed hawthorn 4 6 PRUNUS EMARGINATA Feet 17 Crataegus monogyna Oneseed hawthorn <1-12 18 Prunus emarginata Bitter cherry <1-12 DISCOVERY PARK Acer macrophyllum LOOP TRAIL 19 Bigleaf maple 10.5

3 + 0 0 Alnus rubra 15 PINUS CONTORTA 20 Red alder 25 16 CRATAEGUS MONOGYNA 21 Prunus emarginata Bitter cherry <1-12 17CRATAEGUS MONOGYNA 22 Crataegus monogyna Oneseed hawthorn 10 23 Alnus rubra Red alder 15 PINUS PRUNUS EMARGINATA CONTORTA7 8 PINUS CONTORTA 18 4 Crataegus monogyna + 24 Oneseed hawthorn 13 0 PINUS CONTORTA 9 10 PINUS CONTORTA 0 FOREST AREA ACER MACROPHYLLUM 19 25 Alnus rubra Red alder 20 PRUNUS EMARGINATA 3 7 7 21 3 PINUS 7 8 26 Crataegus monogyna, Alnus Oneseed hawthorn, red NA 3 7 8

3 7 11 7 CONTORTA ALNUS RUBRA CRATAEGUS 20 22 MONOGYNA rubra, Prunus emarginata alder, bitter cherry thicket ALNUS RUBRA 6 7 12 PINUS CONTORTA 233 CRATAEGUS ALNUS RUBRA 24 13 PINUS CONTORTA 25 MONOGYNA PINUS CONTORTA 14 CRATAEGUS 26 MONOGYNA Department of Natural Resources and Parks Wastewater Treatment Division

1901_9468a _Discovery_Park_Meeting_BOARD3.ai RESTORATION PLAN West Point Treatment Plant

Promoting a healthy environment LEGEND J pipe (ruar cleared RTK Points – June 2018 King County is working closely with Seattle to here) ARBMEN 29.6” Concrete edge Parks and Recreation on a restoration plan Tree Preservation that blends into the natural environment RONU thicket and supports the park’s wildlife. We are Himalayan Blackberry Treatment and Shrub Planting committed to replanting two trees for every Ruar edge Ruar edge Ruar edge tree removed. Ruar edge Native Prairie Mix Seeding and Metro sewer Native Shrub Restoration Power metro J pipe Metal drum OPTIONAL - Continuation of Stair Stair Ruar edge RONU thicket Native Prairie Mix Seeding Stair Stair Ruar edge PICO <1 and Native Shrub Restoration CL OF FOOTPATH PSME 1.5” Ruar edge PSME 2

CL OF SASC SHRUB FOOTPATH PICO 8 RONU thicket SASC shrub PICO 1.5 Entry point PSME 1 CL OF (existing) PICO <1 FOOTPATH 0 15 30 60 Mulch Feet Gravel trail Gravel trail

Mulch Mulch PICO 5.5 CL OF FROR 9.5 PICO 4 FOOTPATH PSME <1 Entry point PICO 2.5 (existing) SASC PSME 1 PSME <1 large PREM thicket PSME <1 ACCI 2 shrub PREM Thicket PICO 3.5 ACCI 2 PSME <1 PREM thicket PICO 4 PICO 9.5 SALSCO (shrub) PICO 4.5

HODI (shrub) PICO 3 CL OF PICO 3 FOOTPATH

CL of PICO 1 (PICO Prunus sp 1 footpath ~8-12’ tall) PICO 2 PICO 1.5 PICO 1 PICO 1 PICO 1 PICO 1 PICO 1.5 CL OF CRAMON CL OF PSME 1.5 FOOTPATH (multi FOOTPATH CL OF PICO 1 stem) 4 FOOTPATH CL OF Alru 3 FOOTPATH PICO 1 CL OF FOOTPATH PICO 2 PICO 1.5

Department of Natural Resources and Parks Wastewater Treatment Division

1901_9468a _Discovery_Park_Meeting_BOARD4.ai PLANT PALETTE West Point Treatment Plant

Recommended tree and plant palette for restoration plan, provided by Seattle Parks and Recreation.

RECOMMENDED TREE REPLACEMENT PALETTE TREES TO BE PROTECTED Species Name Common Name Type Species Name Common Name Acer circinatum Vine Maple Deciduous Pinus contorta Lodgepole Pine Common Snowberry Acer macrophyllum Bigleaf Maple Deciduous Fraxinus Latifolia Oregon Ash Oregongrape Alnus rubra Red Alder Deciduous Prunus Emarginata Bitter Cherry Pinus contorta Lodgepole Pine Coniferous Acer macroph yllum Bigleaf Maple Pseudotsuga menziesi i Douglas Fir Coniferous

Tsuga heterophylla Western Hemlock Coniferous NATIVE SEEDING Botanic Name Common Name PLANT PA LETTE Achillea Millefolium Yarrow

Botanic Name Common Name Type Rosa Nutkana Nootka Rose Acer circinatum Vine Maple Shrubs Symphoricarpus albus Common Snowberry

Amelanchier alnifolia Serviceberry Shrubs Elymus glaucus Blue Wildrye Berberis aquifolium Tall Oregongrape Shrubs Balsamorhiza deltoidea Puget Balsamroot Berberis nervosa Dwarf Oregongrape Shrubs Agrostis exerata Spike Bentgrass Bromus vulgaris Columbia Brome Graminoids Lupinus polyphyllus Big Leaf Lupine Festuca occidentalis Western Fescue Graminoids Rubus parviflorus Thimbleberry Fragaria vesca ssp bracteata Woods Strawberry Forbs and Ferns Solidago canadensis Canada Goldenrod Gaultheria shallon Salal Shrubs Holodiscus discolor Oceanspray Shrubs Douglas Fir Melica subulata Alaska Oniongrass Graminoids Penstemon ovatus Broad-leaved Penstemon Forbs and Ferns Philadelphus lewisii Mockorange Shrubs Polystichum munitum Sword Fern Forbs and Ferns Sword Fern Rubus parviflorus var parviflorus Thimbleberry Shrubs Yarrow Western Symphoricarpos albus var laevigatus Hemlock Common Snowberry Shrubs

Department of Natural Resources and Parks Wastewater Treatment Division

1901_9468a _Discovery_Park_Meeting_BOARD5.ai WHAT WILL THIS PROJECT West Point Treatment Plant LOOK LIKE ONCE FINISHED?

Aerial views of new structure

Existing structure New structure

Existing conditions pre-construction Post-construction and planting After planting establishment period

Department of Natural Resources and Parks Wastewater Treatment Division

1901_9468a _Discovery_Park_Meeting_BOARD6.ai