PROJ00538

• Contract/PO #: C153581
• Contractor Name: Minnesota Canal and Reservoir Company
• Water District: 0
• County: Gunnison
• Bill Number: XB 99-999
• Loan Projects - Doc Type: Feasibility Study

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TABLE OF eONTENTS
(eONTINUED)

7.0 SITE SELEeTION STUDY ................ . . . . . . . . . . . . . . .. 11

7.1 Site Selection Methodology ............................ 11
7.2 Regional Screening ................................. 12
7.3 Fatal Flaw Study. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 13
7.4 Site eharacterization and Ranking ........................ 14
7.5 Expanded Site Selection Study .......................... 17

7.5.1 General.................................... 17
7.5.2 Expanded Site Selection Study . . . . . . . . . . . . . . . . . . . . .. 17
7.5.3 Construction Cost Comparison. . . . . . . . . . . . . . . . . . . . .. 19

8.0 REGULATORY eLASSIFICATION AND REQUIREMENTS. . . . . . . . . .. 20

8.1 General..... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 20
8.2 Jurisdictional Dam vs. Nonjurisdictional Dam . . . . . . . . . . . . . . . .. 20

8.3 Dam Class ...................................... 20
8.4 Dam Size ....................................... 21
8.5 Regulatory Requirements . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 22

9.0 DAM BREAK ANALYSES AND HAZARD eLASSIFICATION . . . . . . . .. 22

9.1 General... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 22
9.2 Development of Floodwave Routing Model .................. 22

9.2.1 The Hazard 3 Model . . . . . . . . . . . . . . . . . . . . . . . . . . .. 23
9.2.2 The HEe-1 Model ............................. 23

9.3 Results of the Dam Break and Floodwave Study ............... 24
9.4 Discussion of Results . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 24

9.4.1 Hazard 3 Results .............................. 24
9.4.2 HEe-l Results ............................... 24
9.4.3 eomparison and Evaluation of Results ................. 24
9.4.4 Hazard elassification Review and Determination. . . . . . . . . .. 26
9.4.5 Mitigation of Dam Breach Floodwave Hazard ............ 26

10.0 EMBANKMENT DESIGN . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 29

10.1 Embankment Design Details . . . . . . . . . . . . . . . . . . . . . . . . . . .. 29

10 .1.1

erest Design ............................ 29