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AN ECONOMICALAN ECONOMICAL
RIVER INTAKE PUMPRIVER INTAKE PUMPSTATIONSTATION
By: Walter T. Winn, Jr., P.E., DWRE, BCEE, F.ASCEBy: Walter T. Winn, Jr., P.E., DWRE, BCEE, F.ASCEGina R. Bolton, P.E., M.ASCEGina R. Bolton, P.E., M.ASCE
Northeast Texas Section WEAT Biennial SeminarNortheast Texas Section WEAT Biennial Seminar
Longview, TexasLongview, Texas
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OverviewOverview
IntroductionIntroduction
Water SupplyWater Supply
Intake ConstraintsIntake Constraints
Unconventional Intake DesignUnconventional Intake Design Modifications to Design after ConstructionModifications to Design after Construction
SubmittalsSubmittals
Resolution of Operational IssuesResolution of Operational Issues ConclusionsConclusions
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Trinity Rural Water SupplyTrinity Rural Water Supply
CorporationCorporation
Located in Trinity, Polk, and Walker CountiesLocated in Trinity, Polk, and Walker Counties
Serves approximately 1,400 customersServes approximately 1,400 customers
System previously served by ground water andSystem previously served by ground water andpurchased water from Trinity River Authoritypurchased water from Trinity River Authority(TRA) Trinity Co. Regional System and the City(TRA) Trinity Co. Regional System and the Cityof Trinityof Trinity
Additional water not available from TRAAdditional water not available from TRARegional System & Trinity. No groundwater ofRegional System & Trinity. No groundwater ofacceptable quality and quantity.acceptable quality and quantity.
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New Source of SupplyNew Source of Supply
Water rights from Lake Livingston owned byWater rights from Lake Livingston owned by
TRA and reserved for local useTRA and reserved for local use
Raw water from Trinity River at headwaters ofRaw water from Trinity River at headwaters of
Lake LivingstonLake Livingston Plant site located 1Plant site located 1-- mile north of SH 19mile north of SH 19
crossing of the Trinity River, west of SH 19crossing of the Trinity River, west of SH 19
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Intake ConstraintsIntake Constraints
Poor soil conditionsPoor soil conditions
High groundwater tableHigh groundwater table
Financial limitationsFinancial limitations
Decided to try unconventional floating pumpDecided to try unconventional floating pump
station designstation design
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Plant Flow DiagramPlant Flow Diagram
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Soil ProfileSoil Profile
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Unconventional Intake DesignUnconventional Intake Design
Submerged intake pipe and intake screenSubmerged intake pipe and intake screen
SelfSelf--priming centrifugal pumpspriming centrifugal pumps
Above ground floating platform systemAbove ground floating platform system
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Modifications to Design AfterModifications to Design After
Construction SubmittalsConstruction Submittals
The pumps selected by Contractor wereThe pumps selected by Contractor were
significantly heavier than the originally specifiedsignificantly heavier than the originally specified
pumpspumps Concrete slab on platform was modified to useConcrete slab on platform was modified to use
light weight concrete and reduce slab thicknesslight weight concrete and reduce slab thickness
from 6from 6 to 5to 5..
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Float Test of PlatformFloat Test of Platform
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Problems Discovered in TestingProblems Discovered in Testing
Platform twisting, putting torque on the postsPlatform twisting, putting torque on the posts
and pipe rollers holding it in place.and pipe rollers holding it in place.
Platform was not level as it was tilting towardsPlatform was not level as it was tilting towards
the corner where the pumps were placed.the corner where the pumps were placed.
Therefore, the weight was not evenly distributedTherefore, the weight was not evenly distributed
across the platform.across the platform.
Back to the drawing board.Back to the drawing board.
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Initial ConfigurationInitial Configuration
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Revised ConfigurationRevised Configuration
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Buoyancy CalculationsBuoyancy Calculations
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Concrete Ballast
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Issues in OperationIssues in Operation
Pumps kept losing primePumps kept losing prime
Operation at design flow rate of 700 gpm wasOperation at design flow rate of 700 gpm was
fine, but unable to reduce the flow rate belowfine, but unable to reduce the flow rate below
300 gpm300 gpm
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Chlorine Dioxide SystemChlorine Dioxide System
Air Release Valve
Electric
Solution Valve
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FIGURE 1INTAKE PUMP CURVES
10.00
15.00
20.00
25.00
30.00
35.00
40.00
45.00
50.00
55.00
60.00
0 100 200 300 400 500 600 700 800
Flow (gpm)
He
ad
(ft)
System
Curve at
131
680 rpm
780 rpm
880 rpm
980 rpm
1080
rpm
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Resolution of Operation IssuesResolution of Operation Issues Pumps kept losing primePumps kept losing primeFound that chlorineFound that chlorine
dioxide injection into pump suction wasdioxide injection into pump suction wasintroducing air. Added electric solution valveintroducing air. Added electric solution valveand air release valve.and air release valve.
Operation at design flow rate of 700 gpm wasOperation at design flow rate of 700 gpm wasfine, but unable to reduce the flow rate belowfine, but unable to reduce the flow rate below300 gpm300 gpmFound that flat pump curves causedFound that flat pump curves caused
VFDs toVFDs to searchsearch for flow set point. Controlsfor flow set point. Controlschanged to set pump speed instead of flow rate.changed to set pump speed instead of flow rate.
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ConclusionsConclusions
Worked through issues to developWorked through issues to develop
unconventional river intake pump station.unconventional river intake pump station. Saved Trinity Rural WSC an estimated $650,000,Saved Trinity Rural WSC an estimated $650,000,
about 65% of the original estimated intakeabout 65% of the original estimated intake
pump station cost.pump station cost.
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Questions?Questions?
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