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Improving Service to Customers by Decommissioning an Elevated Water Storage Tank. Jon C. Ford P.E. – Seattle Public Utilities AWWA-PNWS Conference April 30, 2008. Overview. Seattle Water System Description Maple Leaf 530 Pressure Zone Improvements Analysis Recommended Improvement. - PowerPoint PPT Presentation
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Improving Service to Improving Service to Customers Customers
by Decommissioning an by Decommissioning an Elevated Water Storage Elevated Water Storage
TankTankJon C. Ford P.E. – Seattle Public Jon C. Ford P.E. – Seattle Public
UtilitiesUtilities
AWWA-PNWS ConferenceAWWA-PNWS Conference
April 30, 2008April 30, 2008
OverviewOverview
Seattle Water System DescriptionSeattle Water System Description Maple Leaf 530 Pressure ZoneMaple Leaf 530 Pressure Zone Improvements AnalysisImprovements Analysis Recommended ImprovementRecommended Improvement
Seattle Regional Water Seattle Regional Water SystemSystem
Seattle Public Utilities Seattle Public Utilities Water SystemWater System
1.3 million direct service and wholesale 1.3 million direct service and wholesale customers in King and Snohomish Countycustomers in King and Snohomish County
188,000 retail/100 wholesale service 188,000 retail/100 wholesale service connectionsconnections
Two surface water sources, one Two surface water sources, one (emergency) groundwater source(emergency) groundwater source
1,600 mi. distribution/159 mi. transmission 1,600 mi. distribution/159 mi. transmission mainsmains
15 reservoirs, 7 elevated tanks, 11 15 reservoirs, 7 elevated tanks, 11 standpipesstandpipes
Low Pressures in Seattle’s Low Pressures in Seattle’s Water SystemWater System
Approximately 45 services have Peak Approximately 45 services have Peak Hourly Demand (PHD) pressure less Hourly Demand (PHD) pressure less than 20 psi (<0.1%)than 20 psi (<0.1%)
Approximately 1,500 services have Approximately 1,500 services have PHD pressure between 20 and 30 psi PHD pressure between 20 and 30 psi (0.8%)(0.8%)
Locations of Low Locations of Low PressuresPressures
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Seattle Public Utilities2008 Low Pressure
Improvement Projects
Maple Leaf 53027 Water Services
Below 20 psi
Queen Anne 53011 Water Services
Below 20 psi
Queen Anne 3267 Water Services
Below 20 psi
N
EW
S
Maple Leaf 530 PZ PHD Maple Leaf 530 PZ PHD PressurePressure
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H A
V N
E
NE 95TH ST
RO
OS
EV
ELT
WY
NE
N & NE 65TH ST
NE 80TH ST
NE 65TH ST15T
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V N
E
20T
H A
V N
E
25T
H A
V N
E
35T
H A
V N
E
NE 65TH ST
NE 85TH ST
40T
H A
V N
E
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H A
V N
E
8T
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V N
E
WE
EDIN
PL N
E
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RA
VE
NN
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V N
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ITY
WY
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SA
ND
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INT
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V N
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S WY
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V N
E
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RooseveltReservoir
MapleLeaf
Reservoir
N
EW
S
0 1000 2000 Feet
Water Bodies
20-30 psi
30-40 psi
40-80 psi
> 80 psi
0-20 psi
#S
#S
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#S
#S
Maple Leaf 530 Pressure ZonePHD Pressure
ML 530 W M
Parcels
Base Case - Maple Leaf Tank 515 ft
0-20 psi
> 80 psi
40-80 psi
30-40 psi
20-30 psi
Model Nodes
Base Case PHD Pressure – Low Base Case PHD Pressure – Low Pressure AreaPressure Area
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Reservoir
NE 86TH ST
NE 88TH ST
NE 89TH ST
NE 90TH ST
NE 91ST ST
NE 92ND ST
NE 94TH ST
NE 95TH ST
NE 96TH ST
NE 97TH ST
5T
H A
VE
NE
17T
H A
VE
NE
15T
H A
VE
NE8
TH
AV
E N
E
RO
OS
EV
ELT
WA
Y N
E
N
EW
S
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20-30 psi
30-40 psi
40-80 psi
> 80 psi
0-20 psi
Base Case - Maple Leaf Tank 515 ft
Parcels
ML 530 W M
Maple Leaf 530 Pressure Zone PHD Pressure
#S
#S
#S
#S
#S
0-20 psi
> 80 psi
40-80 psi
30-40 psi
20-30 psi
Water Reservoirs and Tanks
0 400 800 Feet
Maple Leaf 530 PZ
Maple Leaf 430 PZ
Vacant parcels
Low Pressures Due to Maple Leaf Tank Low Pressures Due to Maple Leaf Tank ElevationElevation
550
570
530
510
490
470
450
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Ele
vatio
n, ft
590
NE
85th S
t
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t
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t
NE
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t
NE
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t
NE
91st S
t
NE
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t
NE
94th S
t
Ground Elevation West of Roosevelt Way N.E.
Post-1954 High Point = 472 ft
Min Pressure =18.6 psi
530
515
Pre-1954 High Point = 430 ft
Min Pressure =37 psi
Ground Elevation N
43 ft
85 ft
Maple Leaf 530 PZ MDD Maple Leaf 530 PZ MDD Fire FlowFire Flow
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OO
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Y N
E
N & NE 65TH ST
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V N
E
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E
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35T
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ITY
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1S
T A
V N
E
WOODLAW N AV N
NE 71ST STLATO
NA AV N
E
E G
RE
EN
LAKE DR N
1S
T A
V N
E
NE 100TH ST
NE 103RD ST
RA
VE
NN
A A
V N
E
NE P
RINC ETON WY
MapleLeaf
Reservoir
RooseveltReservoir
N
EW
S
0 1000 2000 Feet
Water Bodies
500-1000 gpm
1000-2000 gpm
2000-4000 gpm
> 4000 gpm
0-500 gpm
#S
#S
#S
#S
#S
Maple Leaf 530 Pressure ZoneMDD Available Fire Flow
ML 530 W M
Parcels
Base Case - Maple Leaf Tank 515 ft
0-500 gpm
> 4000 gpm
2000-4000 gpm
1000-2000 gpm
500-1000 gpm
Hydrant Nodes
Base Case MDD Fire Flow – Low Base Case MDD Fire Flow – Low Pressure AreaPressure Area
#S
#S
#S#S
#S
#S
#S
#S
#S #S #S
#S #S #S#S
#S
#S
#S
#S
#S#S#S
#S #S #S
#S #S #S
#S
#S #S
#S
#S
#S
#S
#S
#S
#S #S#S
#S #S
#S#S
#S
#S#S #S
#S
#S
#S #S
#S #S #S
#S #S
#S #S #S
#S
#S
#S
#S
#S
#S #S
#S
#S
#S
#S
#S
#S
#S
#S
#S#S
#S #S
#S #S #S#S
#S #S
#S #S
#S#S
#S #S
#S#S
#S
#S#S
#S #S
#S
#S
#S
#S
#S
#S
#S
#S
#S
#S
#S
#S
#S
#S
#S
#S #S
#S
#S
#S
#S
#S
#S
#S #S
#S
#S
#S
#S
#S
#S
#S
#S
#S
#S
#S
#S
#S
#S#S#S#S
#S #S #S #S
#S #S #S #S
#S #S #S #S
#S#S#S#S
#S #S #S
#S
#S
#S
#S #S
#S
#S
#S
#S
#S
#S #S #S
#S #S #S
#S #S #S
#S #S
#S#S
#S#S
#S
#S
#S
MapleLeaf
Reservoir
17T
H A
VE
NE
15 T
H A
VE
NE
12T
H A
VE
NE
RO
OS
EV
EL
T W
AY
NE
8T
H A
VE
NE
5T
H A
VE
NE
NE 85TH ST
NE 86TH ST
NE 88TH ST
NE 89TH ST
NE 90TH ST
NE 91ST ST
NE 92ND ST
NE 94TH ST
NE 95TH ST
NE 96TH ST
NE 97TH ST
Vacant parcels
Maple Leaf 430 PZ
Maple Leaf 530 PZ
0 400 800 Feet
Water Reservoirs and Tanks
500-1000 gpm
1000-2000 gpm
2000-4000 gpm
More than 4000 gpm
Less than 500 gpm
#S
#S
#S
#S
#S
Maple Leaf 530 Pressure Zone MDD Available Fire Flow
ML 530 W M
Parcels
Base Case Results
Less than 500 gpm
More than 4000 gpm
2000-4000 gpm
1000-2000 gpm
500-1000 gpm
Hydrant Nodes
N
EW
S
Project ObjectivesProject Objectives
Increase low pressures to at least 20 Increase low pressures to at least 20 psipsi
Determine most cost-effective option Determine most cost-effective option of raising pressures above 20 psiof raising pressures above 20 psi
Determine future of Maple Leaf Determine future of Maple Leaf Tank as water storage facilityTank as water storage facility
Improvement Improvement AlternativesAlternatives
Alternative 1 – Upgrade existing Alternative 1 – Upgrade existing tanktank
Alternative 2 – New higher tankAlternative 2 – New higher tank Alternative 3 – Decommission tankAlternative 3 – Decommission tank Alternative 4 – Decommission tank Alternative 4 – Decommission tank
plus booster pump stationplus booster pump station
Comparison of Comparison of AlternativesAlternatives
550
570
530
510
490
470
450
430
Ele
vatio
n, ft
Base CaseExisting Tank
MaximumTank Level = 530 ftPressure = 25.1 psi
MinimumTank Level = 515 ftPressure = 18.6 psi
Alternative 1Upgrade Tank
MaximumTank Level = 530 ftPressure = 25.1 psi
MinimumTank Level = 525 ftPressure = 23.0 psi
Alternative 2New Tank
MaximumTank Level = 553 ftPressure = 35.1 psi
MinimumTank Level = 548 ftPressure = 32.9 psi
Alternative 3550 Pipeline
MaximumZone Head = 550 ftPressure = 33.8 psi
MinimumZone Head = 540 ftPressure = 29.5 psi
Comparison of Static Pressures at Highest Service Elevation (472 ft)
(Lake ForestPark
Reservoir)
40
10
0
20
30
Pre
ssur
e at
Hig
h P
oint
, psi
590
Alternative 4Booster Pump/
550 Pipeline
MaximumZone Head = 580 ftPressure = 46.8 psi
MinimumZone Head = 580 ftPressure = 46.8 psi
(Lake ForestPark
Reservoir)
Pump
50
530
515
530525
553548 550
540
580
High ElevationPoint (472 ft)
Comparison of Comparison of AlternativesAlternatives
AlternativeAlternative
Alternative 1
Upgrade Tank
Alternative 2
Higher Tank
Alternative 3
Decomm. Tank
Alternative 4
Booster PS
Minimum Minimum Head (ft)Head (ft) 525525 548548 545545 580/545580/545
Required Required ImprovemeImproveme
ntsnts
Seismic Seismic UpgradeUpgradeRecirculatiRecirculation on ImprovemeImprovementsntsSoil Soil RemediatioRemediationn
Demolish Demolish Old TankOld TankNew TankNew TankSoil Soil RemediatioRemediationn
Pump Pump Station Station ModificatioModificationsns
Booster Booster Pump Pump StationStationWatermaiWatermain n ImprovemeImprovements (for nts (for zone zone separation)separation)
Alternatives – PHD Pressure Alternatives – PHD Pressure ResultsResults
PHDPressure
Range (psi)
Number of Parcels
Base CaseExist Tank Min Level
515 ft
Alt 1Upgrade Tank
Min Level 525 ft
Alt 2New Tank Min Level
550 ft
Alt 3No Tank
Min Head 540 ft
Alt 4Booster PSNo Tank
Min Head580 ft
0-20 28 0 0 0 0
20-30 434 210 0 28 0
30-40 393 502 169 371 1
40-80 3,393 3,044 2,361 2,734 3,149
80-120 2,056 2,548 3,770 3,170 3,153
Above 120 1 1 5 2 2
Total 6,305 6,305 6,305 6,305 6,305
Alternatives – MDD Fire Flow Alternatives – MDD Fire Flow ResultsResults
MDDFire Flow
Range (gpm)
Number of Non-Vacant Parcels
Base CaseExist Tank Min Level
515 ft
Alt 1Upgrade Tank
Min Level 525 ft
Alt 2New Tank Min Level
550 ft
Alt 3No Tank
Min Head 540 ft
Alt 4Booster PSNo Tank
Min Head580 ft
0-500 167 34 17 17 17
500-1,000
813 598 394 445 385
1,000-2,000
2,538 2,697 2,353 2,474 2,799
2,000-4,000
2,500 2,666 3,131 2,945 2,765
> 4,000 285 308 408 422 337
Total 6,303 6,303 6,303 6,303 6,303
Alternatives ComparisonAlternatives Comparison
Net Present ValueNet Present Value BenefitsBenefits
Increased PressureIncreased Pressure Increased Fire FlowIncreased Fire Flow Decreased RiskDecreased Risk
CostsCosts Capital CostsCapital Costs O&M CostsO&M Costs
Storage AnalysisStorage Analysis
Storage Storage ComponentComponent DescriptionDescription
Needed in Maple Leaf Needed in Maple Leaf 530 Pressure Zone?530 Pressure Zone?
OperationalOperational Maintains supply when Maintains supply when pumps are shut offpumps are shut off NoNo (gravity feed) (gravity feed)
EqualizingEqualizing Needed when sources Needed when sources cannot meet demandcannot meet demand NoNo (availability > demand) (availability > demand)
Fire Fire SuppressionSuppression
Provides specific Provides specific duration of fire flowduration of fire flow
NoNo (available in Lake (available in Lake Forest Park Reservoir)Forest Park Reservoir)
StandbyStandbyProvides emergency Provides emergency supply when sources supply when sources unavailableunavailable
Only during severe Only during severe emergenciesemergencies
Benefits ComponentsBenefits Components
Increased Increased PressurePressure
Increased Increased
Fire FlowFire FlowDecreased Decreased
RiskRiskValue from Value from customers’ time customers’ time savings savings (hygiene and (hygiene and appliance use)appliance use)Calculated for Calculated for pressure pressure increases increases raising pressure raising pressure up to 40 psiup to 40 psi
Value from Value from reduced risk costs reduced risk costs (death, injury, (death, injury, property damage)property damage)Calculated for Calculated for fire flow increases fire flow increases up to planning-up to planning-level flow level flow requirementrequirement
Value from Value from reduced risk reduced risk costs costs (outages)(outages)
Supply Sources to Maple Leaf 530 Supply Sources to Maple Leaf 530 Pressure ZonePressure Zone
From Tolt Reservoir
Lake Forest Park Reservoir
60 MG
Maple Leaf Reservoir
60 MG
Maple Leaf Tank1 MG
View RidgeReservoir2.5 MG
View RidgeHigh Service Pump
2,000 gpm
RooseveltTurbine
800 GPM
Roosevelt WayRCBV
6,000 GPM
Roosevelt WayPump Station3,000 GPM
Benefits ComparisonBenefits Comparison(5% Discount Rate, 100-yr return)(5% Discount Rate, 100-yr return)
Benefit
Alternative 1
Upgrade Tank
Alternative 2
Higher Tank
Alternative 3
Decomm. Tank
Alternative 4
Booster PS
IncreasedPressure
$1,722,400
$4,188,100 $3,603,700 $4,378,700
Increased Fire Flow
$344,700 $1,037,500 $860,500 $977,100
Storage $100,000 $100,000 $0 $0
Total Benefi
ts
$2,167,100
$5,325,600
$4,464,200
$5,355,800
Benefits of Increased Benefits of Increased PressurePressure
$15
$16
$17
$18
$19
$20
$21
$22
$23
$24
$25
17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40
Pressure, psi
Val
ue
of
1-p
si p
ress
ure
incr
ease
$/E
RU
/Yea
r/p
si
Value ($/ERU/Yr)is area under curve
$151/ERU/Yr
Benefits of Increased Benefits of Increased Pressure Pressure
(5% Discount Rate, 100-yr return)(5% Discount Rate, 100-yr return)
PV Pressure Benefit vs ADD Pressure Increase
$0
$1,000,000
$2,000,000
$3,000,000
$4,000,000
$5,000,000
0 5 10 15 20 25 30
Average ADD Pressure Increase per Parcel, psi
PV
Pre
ss
ure
Be
ne
fit
Alt 1
Alt 3
Alt 2 Alt 4
Planning-Level Fire Flow Planning-Level Fire Flow RequirementsRequirements
(Available Flow at 20 psi Residual Pressure)(Available Flow at 20 psi Residual Pressure)
Single Family: 1,000 gpmSingle Family: 1,000 gpm Multi-Family: 2,000 gpmMulti-Family: 2,000 gpm Schools: 2,250 gpmSchools: 2,250 gpm Commercial: 4,000 gpmCommercial: 4,000 gpm Downtown/Industrial/Major Institutions: Downtown/Industrial/Major Institutions:
8,000 gpm8,000 gpm
Reduced risk of deaths and injuries Reduced risk of deaths and injuries and property damageand property damage
Fire Flow Benefits Fire Flow Benefits CalculationCalculation
Percent Property Damage versus Fire Flow
Available Fire Flow
Per
cen
t P
rop
erty
Dam
age
100% Property Damage at 20% of Target Fire
Flow
Minimum Percent Property Damage at
Target Flow
Benefits of Increased Benefits of Increased Fire Flow Fire Flow
(5% Discount Rate, 100-yr return)(5% Discount Rate, 100-yr return)
Alt 1
Alt 3
Alt 2 Alt 4
PV Fire Flow Benefit vs ADD Fire Flow Increase
$0
$200,000
$400,000
$600,000
$800,000
$1,000,000
$1,200,000
0 100 200 300 400 500
Average ADD Fire Flow Increase per Parcel, gpm
PV
Fir
e F
low
Ben
efit
Alt 1
Alt 3
Alt 4
Alt 2
Storage AnalysisStorage Analysis
Storage Storage ComponentComponent DescriptionDescription
Needed in Maple Leaf Needed in Maple Leaf 530 Pressure Zone?530 Pressure Zone?
OperationalOperational Maintains supply when Maintains supply when pumps are shut offpumps are shut off NoNo (gravity feed) (gravity feed)
EqualizingEqualizing Needed when sources Needed when sources cannot meet demandcannot meet demand NoNo (availability > demand) (availability > demand)
Fire Fire SuppressionSuppression
Provides specific Provides specific duration of fire flowduration of fire flow
NoNo (available in Lake (available in Lake Forest Park Reservoir)Forest Park Reservoir)
StandbyStandbyProvides emergency Provides emergency supply when sources supply when sources unavailableunavailable
Only during severe Only during severe emergenciesemergencies
Maple Leaf 530 Pressure Zone Maple Leaf 530 Pressure Zone Storage AnalysisStorage Analysis
Operational & Equalizing Storage – not Operational & Equalizing Storage – not neededneeded
Fire Suppression Storage – provided in Fire Suppression Storage – provided in Lake Forest Park ReservoirLake Forest Park Reservoir
Standby Storage – need reduced by Standby Storage – need reduced by source availability:source availability: Roosevelt Way RCBV – 6,000 gpmRoosevelt Way RCBV – 6,000 gpm Roosevelt Way PS – 3,000 gpmRoosevelt Way PS – 3,000 gpm View Ridge High Service Pump – 2,000 gpmView Ridge High Service Pump – 2,000 gpm Roosevelt Turbine – 800 gpmRoosevelt Turbine – 800 gpm
Standby Storage Benefit Standby Storage Benefit CalculationCalculation
Value = Risk Cost = Probability of Value = Risk Cost = Probability of Service Outage x Consequences of Service Outage x Consequences of Service OutageService Outage
Probability: 0.02/yr (outage event Probability: 0.02/yr (outage event exceeding MDD)exceeding MDD)
Consequence: $280,000 per episodeConsequence: $280,000 per episode Value = 0.02/yr x $280,000 = Value = 0.02/yr x $280,000 =
$5600/yr$5600/yr PV = $100,000PV = $100,000
Storage and Supply Availability Storage and Supply Availability to to
Maple Leaf 530 Pressure ZoneMaple Leaf 530 Pressure Zone Lake Forest Park Reservoir provides Lake Forest Park Reservoir provides
storagestorage Gravity feed through Roosevelt Way Gravity feed through Roosevelt Way
RCBV/PRVRCBV/PRV Capacity > PHDCapacity > PHD Storage volume (60 MG)Storage volume (60 MG)
Backup sources availableBackup sources available Roosevelt Way Pump StationRoosevelt Way Pump Station View Ridge High Service PumpView Ridge High Service Pump Roosevelt TurbineRoosevelt Turbine
Costs ComparisonCosts Comparison(5% Discount Rate, 100-yr return)(5% Discount Rate, 100-yr return)
Alternative 1
Upgrade Tank
Alternative 2
Higher Tank
Alternative 3
Decomm. Tank
Alternative 4
Booster PS
Tank Tank Capital Capital CostsCosts
$4,550,00$4,550,0000
$6,650,000$6,650,000 $0$0 $0$0
Pump Pump Station Station Capital Capital CostsCosts
$0$0 $50,000$50,000 $105,000$105,000 $1,100,000$1,100,000
Watermain Watermain and Valve and Valve Capital Capital CostsCosts
$0$0 $0$0 $0$0 $1,119,300$1,119,300
O&M Costs O&M Costs (PV)(PV) $200,000$200,000 $400,000$400,000 $0$0 $200,000$200,000
Total Total CostsCosts
$4,750,00$4,750,0000
$7,100,00$7,100,0000
$105,000$105,000 $2,419,30$2,419,3000
Costs with Costs with DemolitioDemolitionn
$4,750,00$4,750,0000
$7,100,00$7,100,0000
$1,105,00$1,105,0000
$3,419,30$3,419,3000
NPV ComparisonNPV Comparison Alternative 1 Alternative 1
NPV = NPV = --$2,582,900$2,582,900
Alternative 2 Alternative 2 NPV = NPV = --
$1,774,400$1,774,400 Alternative 3 Alternative 3
NPV = $4,359,200NPV = $4,359,200 Alternative 4 Alternative 4
NPV = $2,936,500NPV = $2,936,500
B/C ratio = 0.46B/C ratio = 0.46
B/C ratio = 0.75B/C ratio = 0.75
B/C ratio = 42.5B/C ratio = 42.5
B/C ratio = 2.21B/C ratio = 2.21
NPV ComparisonNPV ComparisonNPV Comparison of Alternatives
-$3,000,000
-$2,000,000
-$1,000,000
$0
$1,000,000
$2,000,000
$3,000,000
$4,000,000
$5,000,000
Pressure Benefits Range
NP
V
Alternative 1 Alternative 2 Alternative 3 Alternative 4
Tank Decommission vs. Tank Decommission vs. DemolitionDemolition
No longer needed as No longer needed as water system facilitywater system facility
Value as antenna Value as antenna towertower
Costs of demolition Costs of demolition and soil remediationand soil remediation
Possible landmarks Possible landmarks issueissue
Communication to Communication to customerscustomers
RecommendationRecommendation
Recommend Alternative 3:Recommend Alternative 3: Decommission Maple Leaf Tank and Decommission Maple Leaf Tank and serve the Maple Leaf 530 Pressure serve the Maple Leaf 530 Pressure Zone directly from the 550 PipelineZone directly from the 550 Pipeline
ConclusionsConclusions
Decommissioning the Maple Leaf Decommissioning the Maple Leaf Tank increases pressures and fire Tank increases pressures and fire flowflow
Supply redundancy provides for Supply redundancy provides for minimal outage riskminimal outage risk
Decommissioning still preferred Decommissioning still preferred alternative if demolition costs are alternative if demolition costs are includedincluded
Alt 3 PHD Pressure – Low Alt 3 PHD Pressure – Low Pressure AreaPressure Area
580 Sub-Zone Supply Area
#S#S#S#S#S#S #S #S #S #S#S #S
#S #S #S#S #S
#S #S #S #S#S#S#S
#S #S
#S#S #S#S #S #S
#S #S #S#S #S #S#S #S #S #S
#S#S #S #S#S #S #S #S
#S#S#S #S #S#S#S#S #S #S#S #S
#S #S#S#S #S#S#S#S #S#S#S#S #S #S #S#S
#S#S#S#S #S #S #S#S#S#S #S #S #S #S
#S #S #S#S#S#S #S #S #S
#S #S #S #S #S#S#S#S #S #S #S
#S #S#S#S #S#S #S#S#S#S #S #S#S #S #S #S#S #S#S#S#S
#S #S #S #S #S#S#S#S#S #S #S #S#S #S
#S #S
#S#S #S #S#S#S #S#S#S #S#S#S#S #S#S#S #S#S #S#S#S #S#S#S
#S
#S
#S
#S
#S
#S
#S#S
#S#S
#S
#S
#S
#S
#S #S #S
#S #S #S#S
#S
#S
#S
#S
#S#S#S
#S #S #S
#S #S #S
#S
#S #S
#S
#S
#S
#S
#S
#S
#S #S#S
#S #S
#S#S
#S
#S#S #S
#S
#S
#S #S
#S #S #S
#S #S
#S #S #S
#S
#S
#S
#S
#S
#S #S
#S
#S
#S
#S
#S
#S
#S
#S
#S#S
#S #S
#S #S #S#S
#S #S
#S #S
#S#S
#S #S
#S#S
#S
#S#S
#S #S
#S
#S
#S
#S
#S
#S
#S
#S
#S
#S
#S
#S
#S
#S
#S
#S #S
#S
#S
#S
#S
#S
#S
#S #S
#S
#S
#S
#S
#S
#S
#S
#S
#S
#S
#S
#S
#S
#S#S#S#S
#S #S #S #S
#S #S #S #S
#S #S #S #S
#S#S#S#S
#S #S #S
#S
#S
#S
#S #S
#S
#S
#S
#S
#S
#S #S #S
#S #S #S
#S #S #S
#S #S
#S#S
#S#S
#S
#S
#S
#S#S#S
MapleLeaf
Reservoir
NE 86TH ST
NE 88TH ST
NE 89TH ST
NE 90TH ST
NE 91ST ST
NE 92ND ST
NE 94TH ST
NE 95TH ST
NE 96TH ST
NE 97TH ST
5T
H A
VE
NE
17T
H A
VE
NE
15T
H A
VE
NE8
TH
AV
E N
E
RO
OS
EV
ELT
WA
Y N
E
N
EW
S
Model Nodes
20-30 psi
30-40 psi
40-80 psi
> 80 psi
0-20 psi
Parcels
ML 530 W M
#S
#S
#S
#S
#S
0-20 psi
> 80 psi
40-80 psi
30-40 psi
20-30 psi
Water Reservoirs and Tanks
0 400 800 Feet
Maple Leaf 530 PZ
Maple Leaf 430 PZ
Vacant parcels
Alternative 3 - Supply zone directly from 550 PL
Maple Leaf 530 Pressure Zone PHD Pressure
Alt 3 MDD Fire Flow – Low Alt 3 MDD Fire Flow – Low Pressure AreaPressure Area
580 Booster Zone Area
#S
#S
#S#S
#S
#S
#S
#S
#S #S #S
#S #S #S#S
#S
#S
#S
#S
#S#S#S
#S #S #S
#S #S #S
#S
#S #S
#S
#S
#S
#S
#S
#S
#S #S#S
#S #S
#S#S
#S
#S#S #S
#S
#S
#S #S
#S #S #S
#S #S
#S #S #S
#S
#S
#S
#S
#S
#S #S
#S
#S
#S
#S
#S
#S
#S
#S
#S#S
#S #S
#S #S #S#S
#S #S
#S #S
#S#S
#S #S
#S#S
#S
#S#S
#S #S
#S
#S
#S
#S
#S
#S
#S
#S
#S
#S
#S
#S
#S
#S
#S
#S #S
#S
#S
#S
#S
#S
#S
#S #S
#S
#S
#S
#S
#S
#S
#S
#S
#S
#S
#S
#S
#S
#S#S#S#S
#S #S #S #S
#S #S #S #S
#S #S #S #S
#S#S#S#S
#S #S #S
#S
#S
#S
#S #S
#S
#S
#S
#S
#S
#S #S #S
#S #S #S
#S #S #S
#S #S
#S#S
#S#S
#S
#S
#S
MapleLeaf
Reservoir
17T
H A
VE
NE
15 T
H A
VE
NE
12T
H A
VE
NE
RO
OS
EV
EL
T W
AY
NE
8T
H A
VE
NE
5T
H A
VE
NE
NE 85TH ST
NE 86TH ST
NE 88TH ST
NE 89TH ST
NE 90TH ST
NE 91ST ST
NE 92ND ST
NE 94TH ST
NE 95TH ST
NE 96TH ST
NE 97TH ST
Vacant parcels
ML 430 PZ
ML 530 PZ
0 400 800 Feet
Water Reservoirs and Tanks
500-1000 gpm
1000-2000 gpm
2000-4000 gpm
More than 4000 gpm
Less than 500 gpm
#S
#S
#S
#S
#S
Maple Leaf 530 Pressure Zone MDD Available Fire Flow
ML 530 W M
Parcels
Less than 500 gpm
More than 4000 gpm
2000-4000 gpm
1000-2000 gpm
500-1000 gpm
Hydrant Nodes
N
EW
S
New 12-in W M
New 8-in W M
Alternative 3- Supply Entire Maple Leaf 530 PZ from 550 Pipeline
Questions?Questions?
Decommissioning - Decommissioning - How Do We Make How Do We Make
It Happen?It Happen?Cheryl Capron, Senior Water System Cheryl Capron, Senior Water System
OperatorOperator
Seattle Public UtilitiesSeattle Public Utilities
PNWS-AWWA ConferencePNWS-AWWA Conference
April 30, 2008April 30, 2008
OverviewOverview
Operations input to asset Operations input to asset management processmanagement process
Compensating improvementsCompensating improvements New proceduresNew procedures Operational testingOperational testing RetirementRetirement
Operations Input to Asset Operations Input to Asset Management ProcessManagement Process
How the tank and zone are actually How the tank and zone are actually operatedoperated
Reliability and condition of existing Reliability and condition of existing componentscomponents
Identify all functions of tankIdentify all functions of tank Venting & surge protectionVenting & surge protection Holds positive pressure in zone if pumps failHolds positive pressure in zone if pumps fail Smooths diurnal demand on sourceSmooths diurnal demand on source Provides opportunity to boost Cl2 residualProvides opportunity to boost Cl2 residual
Compensating Compensating ImprovementsImprovements
Pressure relief?Pressure relief? Booster chlorine capability replaced?Booster chlorine capability replaced? More instrumentation?More instrumentation? Upgrade, add, replace pumps?Upgrade, add, replace pumps?
Variable output to match demandVariable output to match demand Hot standby powerHot standby power
Upgrade, add, replace flow control Upgrade, add, replace flow control valves?valves? Adjust valve speedAdjust valve speed
New ProceduresNew Procedures
Revise minimum and maximum zone Revise minimum and maximum zone operating pressuresoperating pressures Hydraulic modelingHydraulic modeling
Response to high and low pressure Response to high and low pressure alarmsalarms When do we shut down gravity supply and When do we shut down gravity supply and
switch to pumps?switch to pumps? Revise SCADA graphics & programmingRevise SCADA graphics & programming Train the operatorsTrain the operators
3-Part Operational 3-Part Operational TestingTesting
PRV LoopPRV Loop Close pump discharge line and start pumpClose pump discharge line and start pump
Pressure Zone Test Scenarios (Tank Pressure Zone Test Scenarios (Tank off-line)off-line) Most likely to go wrong?Most likely to go wrong?
SCADA glitch - valve opens too farSCADA glitch - valve opens too far Power fail – pump stopsPower fail – pump stops
Peak Season TestPeak Season Test Are we absolutely sure we won’t need this Are we absolutely sure we won’t need this
tank anymore?tank anymore?
Operational Test Operational Test ObjectivesObjectives
Verify new 6” PRV loop will function as Verify new 6” PRV loop will function as neededneeded
Verify an existing off-site 4” PRV Verify an existing off-site 4” PRV functions as neededfunctions as needed Document location & effect of discharge Document location & effect of discharge
flow to environment.flow to environment. Revise settings so that new 6” PRV opens Revise settings so that new 6” PRV opens
first.first. Verify high & low psi alarm settings are Verify high & low psi alarm settings are
okok
Test PlanTest Plan
ObjectivesObjectives Prior to TestPrior to Test
Customers ready for pressure changeCustomers ready for pressure change Customer service reps aware of pressure Customer service reps aware of pressure
changes & dirty water from testingchanges & dirty water from testing Fire department aware pressure surges Fire department aware pressure surges
may trigger false alarmsmay trigger false alarms SCADA & new operating procedure readySCADA & new operating procedure ready All compensating improvements completedAll compensating improvements completed
Test PlanTest Plan
Preset the systemPreset the system Reservoir levelsReservoir levels Valves positionedValves positioned
Field staffingField staffing At PRVs to observe & documentAt PRVs to observe & document At tank inlet to put back on line quicklyAt tank inlet to put back on line quickly
Test PlanTest Plan
Step by step procedureStep by step procedure Establish supply to zoneEstablish supply to zone Tank inlet closedTank inlet closed Slowly boost supply to force PRVs openSlowly boost supply to force PRVs open Verify they’re workingVerify they’re working Slowly back off supply to close PRVsSlowly back off supply to close PRVs Adjust pressure settings and alarm Adjust pressure settings and alarm
settingssettings
RetirementRetirement
Disconnect Disconnect Inlet/OutletInlet/Outlet
Where?Where? Abandon in place or remove?Abandon in place or remove?
Overflow?Overflow? Drain?Drain?
RetirementRetirement
Decommission componentsDecommission components Cathodic protectionCathodic protection ElectricalElectrical SCADASCADA Sampling systemSampling system
Demolish or mothball?Demolish or mothball? Mothballing requires regular Mothballing requires regular
inspectionsinspections
Questions?Questions?
