Sayre Report - Hazard Mitigation Web Portal - State of California

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DRAFT TECHNICAL SPECIALTIST’S Burned Area Recovery Team (BART) Resource: Structural Engineering Fire Name: Sayre Fire CA-LFD-1460 December 2008 Author Name: Stevenson Lim, P.E. Transportation Engineer Civil California Department of Transportation, Structure Maintenance and Investigations 100 South Main Street, Los Angeles, CA 90012 Office (213) 897-0153 I. Resource Condition Assessment A. Resource Setting The Burn Area Recovery Team (BART) assigned to the 11,262-acre Sayre Fire inspected the burned area December 1, 2008 through December 12, 2008, as an entire team and with specialist groups. The Sayre fire began on November 15, 2008 and burned a total of 11,262 acres on National Forest System (NFS), state, and private lands. A total of 5,513 acres burned on the Angeles National Forest. Six hundred and thirty six residences were either damaged or destroyed. Majority of the watershed around May #1 & #2, Wilson, Sombrero, Hog, Schoolhouse and Stetson were burned. Fires greatly alter physical characteristics of hillside slopes, stripping natural protective vegetation cover, organic litter and removing barriers that stabilize soil and hold sediment. In addition, chaparral in Southern California has a natural tendency to develop water repellent soils due to their naturally high wax content. This water repellency dramatically increases after a wildfire because waxes vaporize and are driven into the soil by heat. Water repellency reduces infiltration and increases runoff rates. According to the U.S. Forest Service (USDA Forest Service Gen.Tech.Rep.RMRS-GTR-63.2000), peak flows increase 500 to 9,600 percent during the first year after a fire. As a result, burned watersheds generally respond to runoff faster than unburned watersheds and commonly produce flash floods, debris flows, and landslides, which can be devastating to property and human life. B. Survey Methods The BART methodology included: 1. Discussing the fire areas with fire personnel familiar with the fires from both Cal Fire and the USFS
2. Performing a literature review of available maps and documents that included: Topographic maps, Geologic maps, Soils maps, Vegetation maps, Burn intensity maps, Fire history maps, The USFS BAER report (BAER, 2008). 3. Performed ground reconnaissance of the fire areas II. Findings of the On-The-Ground Survey. A. Identify Values At Risk Multiple residential structures were damaged or destroyed by the fire. Seven key infrastructure debris basins need remediation [see Appendix 1], (May #1, #2, Wilson, Schoolhouse, Hog, Sombrero and Stetson) One county agency bridge needs repair) (see Appendix 1)one equipment shed was destroyed [see Appendix 1], numerous Metal Beam Guard Railing (MBGR) timber posts along Fwy. 210 North and South bound Connector to Interstate 5 do require replacement [see Appendix 1]. Four major bridge structures (Glenoaks, Yarnell, and Fwy 210 North and South bound to Interstate 5) closed to the vicinity of the fire area have not suffered any structure damaged. In addition to the above listed areas, lives and property are potentially at risk at sites in flood prone areas, or on roads where flash flooding may cause washouts due to runoff in excess of culvert capacity. Regional water quality supply is potentially at risk from loss of water control on hill slopes. More information is covered in the Hydrology, Geology, Wildlife, and Botany reports for this fire assessment, which also references the abovementioned sites. B. Condition of Values at Risk A sediment or desilting basin is formed by constructed embankment so that sediment-laden runoff is temporarily detained under stable conditions, allowing sediment to settle out before the runoff is discharged. Without mitigation, these basins would pose a moderate degree to Values of Risk from post fire erosion, flash flooding and massive debris accumulation at these basins. Timber planks of Los Angeles County Department of Public Work’s maintenance yard’s “Bailey” bridge was burned. Vehicle tires may be damaged when crossing. This bridge is the link between maintenance yard and the Pacoima trail road. It serves as an alternate access bridge
Page 1 and 2: Sayre Fire Burned Area Recovery Tea
Page 3 and 4: Appendix 7 Values at Risk Site Map-
Page 5 and 6: Protection Area (DPA), and 2,594 ac
Page 7 and 8: B. Threats to Wildlife and Botanica
Page 9 and 10: All VARs identified during the Scop
Page 11 and 12: Sayre Fire Contact List Katie VinZa
Page 13 and 14: DRAFT TECHNICAL SPECIALIST’S SUMM
Page 15 and 16: works at Pacoima dam may be clogged
Page 17 and 18: Evaluations of the Los Angeles Coun
Page 19 and 20: Botanical resource emergencies fall
Page 21 and 22: DRAFT TECHNICAL SPECIALTIST’S Bur
Page 23 and 24: All threat assessments included wit
Page 25 and 26: the Marek Fire on the eastern side
Page 27 and 28: 4. Property owners located below th
Page 31 and 32: VI. Findings of the On-The-Ground S
Page 33 and 34: a total of 682 acres burned by thes
Page 37 and 38: Figure 2. II. Findings of the On-Th
Page 39 and 40: to prevent erosion at high value si
Page 43: III. Emergency Determinations The a
Page 47 and 48: • A detailed structural inspectio
Page 49 and 50: Around the Olive View Hospital and
Page 51 and 52: • Trees that were already declini
Page 53 and 54: Specific Recommendations Any hazard
Page 55 and 56: VI. References California Native Pl
Page 57 and 58: perimeter on the eastern side but d
Page 59 and 60: In general, burn patterns were low
Page 61 and 62: The western spadefoot toad is a sta
Page 63 and 64: • Conduct long-term bird monitori
Page 65 and 66: Penrod, K., C. Cabanero, P. Beier,
Page 67 and 68: Rare plant and natural community lo
Page 69 and 70: sprouting shrubs may be repeatedly
Page 71 and 72: lands is the coast live oak woodlan
Page 73 and 74: • Preserve natural stream bottoms
Page 75 and 76: • Avoid livestock grazing in burn
Page 77 and 78: Figure 3 Dozer lines along Santa Cl
Page 79 and 80: Photos of Vernal Pools in O’Melve
Page 81 and 82: 7. Hog Basin 8. Yarnel Basin 9. Sad
Page 83 and 84: The hospital has several areas that
Page 85 and 86: California Geological Survey Burn S
Page 96 and 97:
Appendix 11 Wildlife Corridor Map
Page 98 and 99:
Appendix 13. CNDDB List of Californ
Page 100 and 101:
Table - 3: Peak Flows Increase for
Page 102 and 103:
Table 5. Values potentially at risk
Page 104 and 105:
Table 8: Rare, Threatened, and Enda
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Sayre Report - Hazard Mitigation Web Portal - State of California

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