1. US Army Corps of Engineers BUILDING STRONG ® Yakima Flood Control Project – Left Bank Yakima, Washington Dennis Fischer, P.E. Levee Safety Program Manager Seattle District May 2012 US Army Corps of Engineers BUILDING STRONG ®

2. Levee Overview  Seattle District (NWS)  Yakima Flood Control Project – Left Bank  The Yakima Flood Control Project – Left Bank consists of 4 sections  The levee incorporates approximately 700 linear feet of the northern Pacific Railway Moxee Branch railway embankment.  Segment ID 5505000021  Left bank of the Yakima River  18,900 feet in length  The Yakima River Flood Control Project was authorized by the Flood Control Act, approved June 28, 1938 (Public Law No. 761)  Operated and maintained by Yakima County  Construction was begun in July 1947 and completed in March 1948  Population at Risk: 1,807 (day), 1,286 (night)

3. BUILDING STRONG ® Yakima Flood Control Project – Left Bank Yakima County, WA

4. BUILDING STRONG ® Yakima Flood Control Project – Left Bank Yakima County, WA InfrastructureNameAmount Electric Substation Roza 1 Schools West Side Christian Primary School Riverside Christian High School Pacific Northwest University of Health Sciences 2 (3) Sewage Treatment Facilities Terrace Heights Sewage District 1 Ties into high ground at the upstream end and a highway embankment a the downstream end. Incorporates 700 ft of railroad embankment from Station 286+00 to Station 293+00.

5. BUILDING STRONG ® Summary of Hydraulics  Yakima Flood Control Project – Left Bank was designed to protect against a 65,000 cfs flood. This was determined to be a 160-year flow.  Analysis performed in 1974 determined that the levee was capable of protecting against a 55,000 cfs flow. This was determined to be a 100-year flow.  Overtopped: No  Failure: No 2 Year Event 30 Year Return Record Flood (2009) 48,200 cfs 75% of height Percent Loaded25%50%75%100% Times Loaded (events)4210

6. BUILDING STRONG ® Performance History  Yakima Flood Control Project – Left Bank has never overtopped.  Yakima Flood Control Project – Left Bank has never breached.  Flood conditions during the three months following construction resulted in considerable berm erosion and loss of levee. This required emergency repairs on several levee sections in the form of additional riprap placement and other protective work. These repairs were completed June 23, 1948.  The southern section of the levee was raised and widened in 1949 to compensate for sediment deposits and channel changes that occurred in 1948.  December 1977, about 670 feet of the levee was damaged near river mile (RM) 112.6. The riverward slope and toe protection were undercut. Rock was replaced along the toe of the levee in 1978.  Flood damage occurred in December 1980 near RM 115 and the Moxee ‐ Hubbard irrigation ditch. The silty ‐ gravel streambank was eroded and threatened to undermine the Moxee ‐ Hubbard irrigation ditch, control gate and service road. A 500 ‐ foot section of the levee required additional riprap bank protection in 1981.

7. BUILDING STRONG ® Performance History  The top of the levee along the Roza Wasteway was raised in 1993.  The levee segment between the former location of the Highway 24 Bridge and the new location (referred to as the KOA levee) was raised to meet Federal Emergency Management Act (FEMA) standards in 1995. The segment became part of the federal levee.  In late 1995 and early 1996 two flood events occurred that damaged the levee from RM 111.5 to 113.3. Rock was placed along this section of the levee to restore it to the original level of protection.  Emergency repairs were made to the NC Machinery in 2011 to prevent an erosive failure.  A levee setback of the southern end was completed in February 2012 in association with erosive damage the occurred during 2009.

8. BUILDING STRONG ® Geomorphology / Foundation Geology The soils are identified primarily as layers of loamy sand, sand and gravel with cobbles, and small boulders to 10 inches with some soils with clay. Test pits were not dug deeper than 8 feet. Pits were dug in July 1946 and November 2011. Depth (feet) USCSDescription 0-2SMSandy loam, some clay 2-4SPCoarse sand with gravel 4-8SP, GP Coarse sand with gravel and gravel with sand, contains cobbles and some boulders Composite Geologic Log (All Test Holes)

9. BUILDING STRONG ® Geomorphology Location of seepage on right bank. Mitigation work has been performed at this site.

10. BUILDING STRONG ® Typical Sections Levee Embankment Elev. 1020 ft12 ft 2.0 1.0 3.0 1.0 Riverside Landside Toe Elevation 1013 Representative Crest Height:7 Ft Crest Width: 12 -14 Ft Foundation Geology: Loamy sand, sand and gravel with cobbles Levee Materials /Zoning:Compacted Fill/Homogeneous Riverside Erosion Protection:Riprap and Sod

11. BUILDING STRONG ® Typical Section Typical Levee Geometry Crown Width12 -14 Feet Landward Levee Height6-9 Feet Riverward Slope3H:1V Landward Slope2H:1V 1954 As-built 1940 As-built

12. BUILDING STRONG ® Repair Sections 1996 Erosion Repair 1997 Erosion Repair

13. BUILDING STRONG ® Repair Sections Repairs following 2009 flood 2012 Sportsman Park levee setback

14. BUILDING STRONG ® Review of Assessment Ratings  Inspection Ratings are taken from the 2010 Periodic Inspection report performed by HDR.  Ratings are often too conservative.

15. BUILDING STRONG ® EMBANKMENT SEEPAGE SUPPORTING PHOTOS Station 45+00: Large trees with locally dense shrubs along toe of landward slope. Station 2+00: 180 LF of large cottonwoods (8-in - 36-in DBH) on landward slope, toe, and within 15 ft of toe.

16. BUILDING STRONG ® EMBANKMENT SEEPAGE SUPPORTING PHOTOS Station 266+00: Area of uneven grade. Appears to be due to poor grade control during construction.

17. BUILDING STRONG ® Culverts  Yakima Levee culverts were installed in 1949 and 1953.  Yakima Levee Culverts were video inspected in May of 2010.  The video inspections revealed heavy sediment, debris, corrosion, small perforations and root penetrations.  The CMP culverts are 60+ years with signs of deterioration.  Therefore, an unacceptable rating was assigned. FG7A – Root Penetrating Wall. [Right Bank] FG27 – Corrosion & Minor Deformation. [Left Bank]

18. BUILDING STRONG ® Assessment Ratings Embankment Seepage Performance ModeICW Rating LST Rating Comment Embankment and Foundation Seepage and Piping Unwanted Vegetation Growth (1)UUSeveral large trees are present in the landward slope of the levee. Trees in the landward slope can cause an increase in seepage through the levee. Additionally, thick brush prevents inspection of the levee slopes and toe. Encroachments (3)UAHDR identified several encroachments in the levee area including power poles, gates, and debris off the levee toe; however, the encroachments identified are not expected to significantly increase the likelihood of failure due to foundation seepage and piping. Settlement (7)UAAreas of unevenness in the levee crown were identified during inspection. These areas appear to be due to poor grading and construction and are not expected to be indications of settlement due to seepage. Cracking (9)AANo evidence of cracking was identified during inspection.

19. BUILDING STRONG ® Assessment Ratings Embankment Seepage (Continued) Performance ModeICW Rating LST Rating Comment Embankment and Foundation Seepage and Piping Animal Control (10)MAThe burrows identified during the inspection were small and infrequent and do not appear to penetrate through the levee. Significant increases in seepage are not expected due to the animal burrows identified during inspection. Culverts/Discharge Pipes (11)UUInterior culvert photos from the 2010 video inspections were received from Yakima County and reviewed. Upon review of the inspection pictures, a few of the culverts displayed heavy sediment, debris, corrosion, small perforations and root penetrations. Video inspection was only performed on a portion of the culverts in this levee system. The conditions observed during the inspection are expected to reflect the condition of the remaining culverts. The interior condition combined with the age of the pipes prompted the inspection team to contradict the findings of the supplemental culvert assessment tab and assign an unacceptable rating for culverts. Underseepage Relief Wells/Toe/Drainage Systems (14) N/A No relief wells or toe drains exist on this levee. Seepage (15)AMNo evidence of seepage was indentified during inspection. Minor seepage has been observed during past flood events. Seepage sites have been repaired and no further seepage has been observed at these locations; however, seepage could occur under full loading of the levee system. The rating team does not expect seepage that initiates a piping failure mode. Head will dissipate uniformly through the embankment and foundation, not allowing for conditions in which critical exit gradients will be exceeded. The seepage is expected to be controlled and ultimately not a major failure mode concern. Although the levee incorporates approximately 700 L.F. of railroad embankment, the railroad and levee embankment materials are similar and should perform similarly. The railroad sections are not expected to perform less satisfactorily than the levee embankments. Also, smaller head loading will be experienced by the shorter setback railroad sections. Seepage analysis for this levee system is not retained in the records of the Seattle District.

20. BUILDING STRONG ® EMBANKMENT STABILITY SUPPORTING PHOTOS Station 32+00:Eight large trees, 12 to 18-in DBH, on landward slope near toe. Station 298+00: Multiple depressions along crown of levee near riverward slope. Typically 6-in to 8-in deep, 12-in wide, length varies.

21. BUILDING STRONG ® Performance ModeICW RatingLST RatingComment Embankment Stability Unwanted Vegetation Growth (1)UMLarge trees are present at levee toe on both sides of the levee and some in the lower portions of the levee landward toe Overturned trees can uproot parts of the levee embankment and reduce levee stability. The levee is wide in areas with trees embedded in the levee slope. The effect of vegetation toppling, creating progressive slope stability failures, and progressing to breach is not likely. Therefore, a minimally acceptable rating was assigned. Encroachments (3)UAThe inspection team identified several encroachments in the levee area including power poles, gates, and debris off the levee toe. These encroachments are not expected to affect slope stability. Slope Stability (5)MASections of levee with over-steepened slopes were identified during inspection, but they appear stable. No slope stability failures have been observed in association with this levee and none are expected during full loading. Slope stability calculations have not been retained in Seattle District records. Settlement (7)UAAreas of unevenness in the levee crown were identified during inspection. These areas are likely due to poor grading and construction and are not expected to be indications of settlement due to bank instability. Assessment Ratings Embankment Stability

22. BUILDING STRONG ® Performance ModeICW RatingLST RatingComment Embankment Stability Depressions/Rutting (8)UMDepressions between 6-in. to 8-in. deep were identified on the levee crown. The depressions identified are not expected to indicate severe slope instability but may cause ponding of water which can decrease slope stability. Cracking (9)AANo evidence of cracking was identified during inspection. Underseepage Relief Wells/Toe/Drainage Systems (14) N/A No wells or toe drains exist on this levee. Assessment Ratings Embankment Stability

23. BUILDING STRONG ® EMBANKMENT EROSION SUPPORTING PHOTOS Station 85+00: 150 LF of erosion from levee fill prism; 2-3-ft high escarpment of soil eroded from levee prism; erosion less severe for at least 100-150 ft upstream and downstream with minor spots. 2H:1V slope intersects above vertical face of riprap. Recently repaired. Station 85+00: Approximately 50 - 60 LF erosion of bank beyond toe of levee prism, near vertical bank. Recently repaired.

24. BUILDING STRONG ® EMBANKMENT EROSION SUPPORTING PHOTOS Station 276+00: Good sod cover on levee slope. Crown is gravel-surfaced.

25. BUILDING STRONG ® Assessment Ratings Embankment Erosion Performance ModeICW RatingLST RatingComment Embankment Erosion Sod Cover (2)AAGreater than 75 percent of levee sod cover is in good condition. Erosion / Bank Caving (6)MUErosion has occurred in several places along the levee. Eroded sections have been repaired and additional protection has been added; however, due to the extent of past erosive damage, additional erosion is likely during full loading and the levee has been rated a “U” for erosion. Although the levee incorporates approximately 700 L.F. of railroad embankment, the railroad is setback from the mainstem of the Yakima River and not as susceptible to damaging scour and erosion. Therefore, the railroad section is not the critically analyzed section. Riprap Revetments & Bank Protection (12)UMSome toe material has been removed or displaced. Most of the riprap is in good condition. Revetments other than RiprapN/A Revetments other than riprap are not incorporated in the levee.

26. BUILDING STRONG ® CLOSURE STRUCTURES Sandbag Closure 3 ft high, 125 ft long, operated by the Bureau of Reclamation Storage and Condition A The sandbags are stored in the field shop and are secure. The bags are in acceptable condition. Sand is readily available from several sources for use in the closure. Available Supply A The supply of bags exceeds the number required for this closure. The supply of sand is also sufficient. The space available for assembling the closure is larger than needed. Operating Plan and Experience (Primary Factor) M The personnel in charge are familiar with the procedures and effort involved. There is no written set of operational plans for when to set up the closure. Miscellaneous Issues A No miscellaneous issues affecting ability to set closure structure.

27. BUILDING STRONG ® CLOSURE STRUCTURES Culvert Gate Closure Moxee Co. irrigation canal culvert at the upstream end of the Bureau of Reclamation protection dike for Wasteway No. 2. Consists of a 48”x72” reinforced concrete culvert w/ two 36”x48” hand ‐ operated screw lift gates. Installed by Bureau of Reclamation. The closure does not appear to be in use and is a state of disrepair. Operating Plan and Experience M There is documentation establishing who is responsible for this closure but not for when it should be set during flood events. Those responsible for this closure understand how to set the closure. Operating Environment and Access M The closure has been set within the last 5 years but not recently. It has been set at various times of the year and can be shut off with emergency actions if necessary. Condition and Recent Maintenance History (primary factor) M The closure is in fair condition but is maintained and inspected by the Bureau. Miscellaneous Issues M A lack of communication between the levee sponsor and the Bureau could lead to this closure not being set at the proper time. Additional documentation establishing the timing for setting the closure is needed.

28. BUILDING STRONG ® Consequence Data Summary  Weighted Fatality Rate: 0.45  Threatened Population with Breach prior to Overtopping: Day- 421 Night- 299  Threatened Population with Overtopping: Day- 176 Night- 125  Estimated Loss of Life with Overtopping: 1  Estimated Loss of Life Breach Prior to Overtopping: 2  Number of structures Inundated: 665  Economic Damages: $46,220,000 Infrastructure NameAmount Electric Substation Roza 1 Schools West Side Christian Primary School Riverside Christian High School Pacific Northwest University of Health Sciences 2 (3) Sewage Treatment Facilities Terrace Heights Sewage District 1 One of the electrical substations, "North Park," included in the protected area has been removed. Only the "Roza" substation is still in use. One additional school, Pacific Northwest University of Health Sciences, is also located in this protected area. The primary school and high school enroll approximately 550 students. This school appears to have not been included in the census data. Due to the number of students in this school, the young age of the students, and the difficulty of evacuating the school, a population day index factor of 1.4 was used.

29. BUILDING STRONG ® Emergency Preparedness  Evacuation Planning = Minimally Acceptable. ► Yakima County created an emergency action plan in 2007 that established authorities and procedures for evacuation planning and execution. No evacuation map has been created.  Community Awareness = Minimally Acceptable. ► Flood fighting teams are familiar with the equipment needed for flood fighting but no specific community awareness efforts have been made to raise awareness of the hazards surrounding the levees.  Flood Warning Effectiveness = Acceptable. ► The Yakima County emergency action plan includes authorities and procedures for flood warnings. The plans involve use of several media for flood warning.

30. BUILDING STRONG ® Assessment Rating Summary Primary Factors Embankment & Foundation Seepage - M Embankment Stability - A Erosion - U Culvert Gate Closure - M Sand Bag Closure - M

31. BUILDING STRONG ® Major Contributors to Overall Risk Rating

32. BUILDING STRONG ® Major Contributors to Risk Prior to Capacity Exceedance

33. BUILDING STRONG ® Segment Ratings Compared to All Segments

34. BUILDING STRONG ® Performance Index vs Life Loss Overtopping Prior to Overtopping

35. BUILDING STRONG ® Risk Whisker

36. BUILDING STRONG ® Performance Index vs Property Loss

37. BUILDING STRONG ® Recommended LSAC Rating  Prior to Capacity Excedance LSAC = xx  Capacity Excedance LSAC = xx  Recommended LSAC = xx  Add Reasons for adjusting LSAC rating