1. PROGRESSION OF EROSION TECHNOLOGY FOR SITES and WINDAM B EROSION TESTING WORKSHOP Maricopa County, AZ October 19 & 20th

2. TYPICAL FLOOD CONTROL STRUCTURE

3. EARLY SPILLWAY DAMAGE 1964?

4. Earth and vegetated emergency spillways are designed on the basis that some erosion or scour may be permissible if its occurrence is infrequent..... maximum permissible velocity will be in accordance with the values in SCS-TP-61. The velocity limitations are based on the maximum discharge in routing the emergency spillway hydrograph..

6. SCS TP-61

8. SCS TR-52

9. RESEARCH AND PROCEDURE REFINEMENT Emergency Spillway Flow Study Task Group formed in 1983 to gather data from field spillways Emergency Spillway Flow Study Task Group formed in 1983 to gather data from field spillways Refined analyses and additional data resulted in stress approach to grassed waterway design (USDA Ag Handbook 667, 1987) Refined analyses and additional data resulted in stress approach to grassed waterway design (USDA Ag Handbook 667, 1987) ARS research improved understanding of erosion processes, including headcuts. ARS research improved understanding of erosion processes, including headcuts. Design and analysis of Earth Spillways Team assigned task of developing new criteria from results of research and field data acquisition efforts. Design and analysis of Earth Spillways Team assigned task of developing new criteria from results of research and field data acquisition efforts.

10. ESFSTG DATA COLLECTION

11. GRASS PROTECTION RESEARCH

12. RESEARCH AND PROCEDURE REFINEMENT Emergency Spillway flow study task group formed in 1983 to gather data from field spillways Emergency Spillway flow study task group formed in 1983 to gather data from field spillways Refined analysis and additional data resulted in stress approach to grassed waterway design (USDA Ag Handbook 667, 1987) Refined analysis and additional data resulted in stress approach to grassed waterway design (USDA Ag Handbook 667, 1987) ARS research improved understanding of erosion processes, including headcuts. ARS research improved understanding of erosion processes, including headcuts. Design and analysis of Earth Spillways Team assigned task of developing new criteria from results of research and field data acquisition efforts. Design and analysis of Earth Spillways Team assigned task of developing new criteria from results of research and field data acquisition efforts.

13. EROSION PROCESS RESEARCH

14. RESEARCH AND PROCEDURE REFINEMENT Emergency Spillway flow study task group formed in 1983 to gather data from field spillways Emergency Spillway flow study task group formed in 1983 to gather data from field spillways Refined analysis and additional data resulted in stress approach to grassed waterway design (USDA Ag Handbook 667, 1987) Refined analysis and additional data resulted in stress approach to grassed waterway design (USDA Ag Handbook 667, 1987) ARS research improved understanding of erosion processes, including headcuts. ARS research improved understanding of erosion processes, including headcuts. Design and analysis of Earth Spillways Team assigned task of developing new criteria from results of research and field data acquisition efforts. Design and analysis of Earth Spillways Team assigned task of developing new criteria from results of research and field data acquisition efforts.

15. DAMS – DAMS2 - SITES Dam design and reservoir routing software Dam design and reservoir routing software Evolved over years as criteria developed Evolved over years as criteria developed Originally developed for mainframe and limited computational power Originally developed for mainframe and limited computational power PC version released in 1989 PC version released in 1989 Became SITES when earth spillway model was incorporated in approximately 1996. Became SITES when earth spillway model was incorporated in approximately 1996. SITES continued to be refined with changes in computational power and design/analysis needs. SITES continued to be refined with changes in computational power and design/analysis needs. Erosionally effective stress concepts of Ag Handbook 667 now replace permissible velocities for stability design. Erosionally effective stress concepts of Ag Handbook 667 now replace permissible velocities for stability design. SITES spillway erosion model now replaces the TR-52 bulk length criteria. SITES spillway erosion model now replaces the TR-52 bulk length criteria. Integrated Development Environment (interface) for Windows replaces the card image input used in early mainframe applications Integrated Development Environment (interface) for Windows replaces the card image input used in early mainframe applications

16. SITES Focus on design Focus on design – Criteria coded – Multiple hydrographs for design Routing based on rating tables Routing based on rating tables Erosion (auxiliary spillway) Erosion (auxiliary spillway) – Potential for breach – Broad range of natural geologic materials – Two dimensional

17. SITES SPILLWAY EROSION MODEL (Three Phases) 1.SURFACE EROSION (Cover Destruction) 2. CONCENTRATED FLOW EROSION 3. HEADCUT ADVANCE

18. 3 PHASE Spillway Erosion Model 1.SURFACE EROSION (Cover Destruction) 3. HEADCUT ADVANCE 2. CONCENTRATED FLOW EROSION

19. SITES SITES –Developed over time –Focus on design –Rating table based routing SITES Earth spillway erosion SITES Earth spillway erosion –Focus on breach potential of vegetated spillways –Three phase erosion model (iterative application) –Broad range of geologic materials represented by K h –Two dimensional erosion (width not considered) SUMMARY PROGRESSION OF EROSION ECHNOLOGY (SITES)

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21. STABILITY The tractive stress of the vegetated earth spillway is computed from the 6 hour SDH storm. The tractive stress of the vegetated earth spillway is computed from the 6 hour SDH storm.

22. INTEGRITY This is the design to make sure the spillway does not breach from the FBH storm. This is the design to make sure the spillway does not breach from the FBH storm. This requires geologic information from the entrance of the spillway through the valley floor. Valley floor is the lowest point where erosion begins. This requires geologic information from the entrance of the spillway through the valley floor. Valley floor is the lowest point where erosion begins.