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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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Click to add headlineEXISTING RIVER PUMPING STATION

EXISTING PUMPS

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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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FLOOD HISTORY

WOOD BEAMS SUPPORTING FLOOR

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PUMP STATION DURING 1997 FLOOD

PUMP STATION DURING 2009 FLOOD

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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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PILE INSTALLATION

PILES INSTALLED WITH CAPS

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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 FLOOR PLAN

PUMP STATION INTERIOR

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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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COFFERDAM INSTALLATION

COFFERDAM DRAINED

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TEMPORARY WATER SUPPLY

INTAKE CONSTRUCTION

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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

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BEFORE AFTER

QUESTIONS?