USEPA / AmerenUE

Sioux Power Plant

Intake Structure Site Visit
March 4, 2009 USEPA Intake 

Structure Site Visit

Sioux Power Plant General No

 Two identical 

steam-generating units: ~950 MW

 Began Operation: 

1967, 1968

 Capacity Factor: 

66.4% (2008)

 WFGD scrubbers 

under construction
March 4, 2009 USEPA Intake 

Structure Site Visit

Sioux Power Plant

Mississippi River Overview

 Drainage area: 

~189,000 mi2

 Located in Pool 26 Water elevation 

dependent upon USACE operation

 Large water volume Historic high flow 

events (Grafton IL):

 1993: 598,000 cfs 2008: 439,000 cfs
March 4, 2009 USEPA Intake 

Structure Site Visit

Sioux Power Plant

Before 1993 Mississippi River Flo
March 4, 2009 USEPA Intake 

Structure Site Visit

Sioux Power Plant

1993 Mississippi River Flood
March 4, 2009 USEPA Intake 

Structure Site Visit

Sioux Power Plant

Before 1993 Mississippi River Flo
March 4, 2009 USEPA Intake 

Structure Site Visit

Sioux Power Plant

1993 Mississippi River Flood
March 4, 2009 USEPA Intake 

Structure Site Visit

Sioux Power Plant

Intake Structure Design

 Canal intake Average 2007-2008 Mississippi wa

withdrawal ~430,000gpm (~958cfs

 Design flow = 520,000gpm (1,160 Four intake bays/pumps
March 4, 2009 USEPA Intake 

Structure Site Visit

Sioux Power Plant

Intake Configuration
March 4, 2009 USEPA Intake 

Structure Site Visit

Sioux Power Plant

Intake Configuration
March 4, 2009 USEPA Intake 

Structure Site Visit

Sioux Power Plant

Intake Configuration
March 4, 2009 USEPA Intake 

Structure Site Visit

Sioux Power Plant

Intake Structure Drawing
March 4, 2009 USEPA Intake 

Structure Site Visit

Sioux Power Plant

Traveling Screen & Bar Rack Des

 Bar rack on 3” center 1.4 fps screen approach velocity 1/2” mesh screens Screen wash discharge to flume Screen rotation

 Determined by ∆P “Normal” (6”) “Fast” (10”) Auto rotation 1/shift
March 4, 2009 USEPA Intake 

Structure Site Visit

Sioux Power Plant

Intake Bay Drawing
March 4, 2009 USEPA Intake 

Structure Site Visit

Sioux Power Plant

Intake Structure Bar Rack
March 4, 2009 USEPA Intake 

Structure Site Visit

Sioux Power Plant

Intake Structure Maintenanc

 Scheduled routine visual inspectio Scheduled diver inspection
March 4, 2009 USEPA Intake 

Structure Site Visit

Sioux Power Plant

Intake Structure Debris & Icing Im

 Historic debris issues

 Leaves during Spring and Fall Traveling screen damage Bar rack damage

 Historic icing issues Load reduction and outage time
March 4, 2009 USEPA Intake 

Structure Site Visit

Sioux Power Plant

Intake Debris Photographs
March 4, 2009 USEPA Intake 

Structure Site Visit

Sioux Power Plant

Intake Debris Photographs
March 4, 2009 USEPA Intake 

Structure Site Visit

Sioux Power Plant

Traveling Screen
March 4, 2009 USEPA Intake 

Structure Site Visit

Sioux Power Plant

Traveling Screen
March 4, 2009 USEPA Intake 

Structure Site Visit

Sioux Power Plant

Intake Impingement Mortality Stu

 Conducted in 2005-2006 No T&E species ~98.2% shad & drum ~99.2% shad/drum/carp
March 4, 2009 USEPA Intake 

Structure Site Visit

Sioux Power Plant

Intake Draft Technology Assessm

 Conducted prior to remand of Phase II Rule Fine mesh screens not evaluated per Phase I Bar rack with barrier

 1” spacing located at canal entrance 0.4fps approach velocity Trash rake system $34M (2002 estimated)

 Barrier net

 1⁄4” mesh located at canal entrance 0.2fps approach velocity Manual cleaning using divers $29M (2002 estimated)
March 4, 2009 USEPA Intake 

Structure Site Visit

Sioux Power Plant

Intake Draft Technology Assessment 

 Wide slot cylindrical wedgewire screens

 Bulkhead mounting at canal entrance, 0.5fps approach v 8 screens (each 7’Dx23’L) Air backwash system (no provisions for biofouling) $61.5M (2002 estimated)

 Ristroph screens with expanded intake

 1.0fps screen approach velocity, 3/8” screen mesh Two new bays with pumps New fish return system $63.4M (2002 estimated)

 Ristroph screens with reduced intake flow

 1.0fps screen approach velocity, 3/8” screen mesh 21% flow reduction New fish return system $58.4M (2002 estimated)
March 4, 2009 USEPA Intake 

Structure Site Visit

Sioux Power Plant

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