Specifications

Table of Contents
EAA Storage Reservoirs Revised Draft PIR and EIS February 2006
vii
5.3 ALTERNATIVE PLANS........................................................................................ 5-12
5.3.1 Evaluation Tools................................................................................................ 5-12
5.3.2 Alternative Plans Descriptions........................................................................... 5-12
5.3.2.1 Reservoir Embankment Construction..........................................................
5-17
5.3.2.2 Cut-off Wall.................................................................................................
5-19
5.3.2.3 Wave Breaking Bench ................................................................................. 5-20
5.3.2.4 Riprap Slope Protection...............................................................................5-20
5.3.3 Pump Station Design.......................................................................................... 5-20
5.3.4 Culverts..............................................................................................................
5-20
5.3.5 Ogee Spillways ..................................................................................................
5-21
5.3.6 Seepage Canals .................................................................................................. 5-21
5.3.7 Emergency Overflow Spillway.......................................................................... 5-22
5.3.8 Conveyance Canals Design................................................................................ 5-22
5.3.9 Flood Damage Reduction ..................................................................................
5-22
5.3.10 Land Requirements............................................................................................
5-22
5.3.10.1 Alternative 2................................................................................................. 5-22
5.3.10.2 Alternative 3................................................................................................. 5-23
5.3.10.3 Alternatives 4, 5, and 6 ................................................................................ 5-23
5.3.10.4 Acquisition and Construction Assumptions................................................. 5-23
5.3.11 Additional On-Site Management Measures....................................................... 5-24
5.3.11.1 Seepage Management Buffers ..................................................................... 5-24
5.3.11.2 Deep Water Refugia..................................................................................... 5-25
5.3.11.3 Littoral Shelves............................................................................................5-26
5.3.11.4 Stormwater Treatment Area (STA) ............................................................. 5-26
5.3.12 Costs of Alternative Plans and Components...................................................... 5-26
5.3.12.1 Calculation of Average Annual Cost........................................................... 5-28
5.3.12.2 Earthwork Cost Estimates............................................................................ 5-29
5.3.12.3 Pump Plant Cost Estimates.......................................................................... 5-29
5.3.12.4 RCC Cost Estimates..................................................................................... 5-30
5.3.12.5 Cut-Off Wall................................................................................................ 5-30
5.3.12.6 Other Structures ...........................................................................................
5-30
5.3.12.7 Planning, Engineering and Design............................................................... 5-30
5.3.12.8 Construction Management...........................................................................
5-30
5.3.12.9 Contingency.................................................................................................
5-30
5.3.12.10 Real Estate Cost Estimates........................................................................... 5-31
5.4 COMPARING ENVIRONMENTAL EFFECTS AND PROJECT COSTS OF
ALTERNATIVE PLANS..................................................................................
5-31
5.4.1 Environmental Effects ....................................................................................... 5-31
5.4.1.1 Fish and Wildlife..........................................................................................
5-34
5.4.1.2 Water Quality............................................................................................... 5-34
5.4.1.3 Socioeconomics ........................................................................................... 5-34
5.4.2 Environmental Benefits .....................................................................................
5-35
5.4.2.1 Quantification of Ecological Benefits Methodology................................... 5-36
5.4.2.2 Summary of Annualized Benefits................................................................
5-42
5.4.2.3 Quantification of System-Wide Benefits.....................................................
5-47
5.4.3 Ecological Benefit Quantification of Local Environmental Design Features ...
5-47