Post on 28-Apr-2019
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Moorhead Public ServiceRiver Intake & Pump StationpTransitioning From a Flood Liability
to a Sustainable Asset
G th f M h d d i 1950
WATER SYSTEM BACKGROUND
• Growth of Moorhead during 1950s was depleting groundwater supply.
• 6 MGD Water Treatment plant was constructed in 1961.
• Intake & Pump Station at the Red River built the same year.
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WATER SYSTEM BACKGROUND
• 1995 New 10 MGD Surface Water Treatment Plant constructed.
• Red River is primary water source along with 7 municipal wells.
• In 2012, the average daily water g yusage was 4.52 MGD.
• Approximately 80% of water treated is from Red River.
EXISTING PUMP STATION’S LIABILITIES
• Three pumps in the base of the building were only at 22’ above river elevation.
• Infrastructure was near or past its useful life expectancy (>50 years).
• Pumps were inefficient and difficult to control flow.
• The Pump Station had no back‐up power supply.
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EXISTING INTAKE& NEED FOR NEW
k l d h b k f h i• Intake was located on the bank of the river
• Intake was prone to clogging by debris in the river
• Intake screen needed to be manually cleaned to remove leaves and other debrisremove leaves and other debris
• Intake was prone to pull in poorer quality water after rain events (storm water outlet upstream)
EXISTING INTAKE
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INTAKE SCREEN AFTER FLOOD
FLOODING• During major floods the Pump Station needed sand
bagging, sump pumps, and supports to keep water out of the building
• MPS’ Staff member needed to monitor Pump Station 24 hours a day during high river flows
• River pumping capacity was limited during flood events (<1000 gpm)
• Floods have become more frequent and severeq
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DESIGN OBJECTIVES
Minimize risk of flooding
Match capacity to current water demands ‐ Provide provisions for expansion
Locate intake to capture best water available
Design a reliable, long life pump station
DESIGN CHALLENGES• Utilize existing pump station location
• Build above flood stageg
• Unstable site and slip plane
• Zebra mussel (veliger) in the Red River
• Allow other future flood protection work
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SITE CONSTRAINTS
• Mitigation required by f difunding source
• Unable to move location
– Build higher
• Remove existing soil load from river bankload from river bank
PUMP STATION SLIP PLANE
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FOUNDATION DESIGN
• Piles carry additional building weight
• Wetwell and pump station are “stacked” but isolated from each other
• Existing levee removedg
FOUNDATION LAYOUT
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PUMP STATION ELEVATION
• Highest flood on record: 41 feet
• Existing pump elevation: 22 feet
• New pump station operations floor: >45 feet
PUMP STATION OPERATING FLOOR
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PUMP CONFIGURATION
Three Vertical Turbine Pumps
– Flowrate adjustable between 3.6 to 6.4 mgd (2,500 to 4,400 gpm)
– Equipped with VFDs
Expandable to Four PumpsExpandable to Four Pumps
– 10 mgd with pump change out
SYSTEM DEMAND CURVE
200.00MPS Raw Water Transmission Pipeline ‐ Demand Curve
80 00
100.00
120.00
140.00
160.00
180.00
Head
(ft)
System Demand
Pump 3.75
Pump 4.5
Pump 5.25
Pump 4.5+5.25
40.00
60.00
80.00
0 1,000 2,000 3,000 4,000 5,000 6,000 7,000 8,000 9,000
Flow (GPM)
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PUMP STATION INTERIOR
RIVER INTAKE
• Moved to center of the river channel
• 10 mgd capacity
• Zebra mussel resistant screen
• Equipped with air burst
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INTAKE PIPELINE
• 30 inch RCP from the existing intake to th t ll ( i t l 200 f t)the wetwell (approximately 200 feet)
• Installed CIPP (cured in place pipe) to repair pipe joint separation
• Low disturbance of soil
OTHER PROJECT COMPONENTS
• Electrical Transformer Relocated
• Generator Plug Connection