Michael Pantell, E.I.T. Peterson Brustad Inc. • Model Folsom Flood Scenarios • During Probable Maximum Flood (PMF) • Varying Folsom Dam Outflows • Multiple Breach Locations and Methods • Results • Floodplain Depths • Mortality • Property Damage • Why? • Information not Available to public • To Obtain Masters Degree  Built in 1956  Owned by USBR  Storage  Approx. 1 Mil Ac-ft  12 structures  Concrete  Main dam  Earthen  2 Wing

 1 Auxiliary Dam Reference: USBR “Folsom Dam Facility Map”  8 Dikes Sacramento Folsom River

Sacramento Probable Maximum Flood

 American River 1000000 900000 Peak ≈ 900,000 cfs

Basin 800000

700000  PMF 600000 )  Developed by 500000 Flow ( cfs USACE 400000 300000  Project Design 200000 Flood 100000 0 0 12 24 36 48 60 72 84 96 108 120 132 144 156 168 180 192  Approx. 25,000 Time (hours) year event Auxiliary Spillway  Powerhouse Folsom Dam  Flow = 6900 cfs  8 Tainter Gates  5- Main  3- Emergency  Auxiliary Spillway  Designed to PMF event Dam Outflow

500 PMF Event

490 Overtopping 480 Elevation 470 460

450

440

430

420

410

400 Elevation (NAVD88 feet) Elevation

390

380

370

360

350 50000 100000 150000 200000 250000 300000 350000 400000 450000 500000 550000 600000 650000 700000 750000 800000 850000 900000 950000 1000000

Outflow (CFS) Without Spillway With Spillway  Mechanisms  Overtopping  Piping  Earthquake  Etc

 Right Wing Dam  Northern Breach  Mormon Auxiliary Dam  Southern Breach  Tallest and longest earthen structures North Earthen structure South Earthen structure

LargerMacDonald Breach Von Thun = Longer & MacDonald Formation Von TimeThun & 𝑆𝑆𝑆𝑆𝑆𝑆𝑆𝑆 ∝ 𝑡𝑡𝑡𝑡𝑡𝑡𝑡𝑡  MacDonald, et. al.et. al. Gillette et. al. Gillette

 Large Breach Width Long- ft Formation3047 Time 374 3916 331  Von Thun & Gillete Height Small- ft Breach 47 47 76 76  Short Formation Time Formation 4.4 0.8 4.1 0.7 Time (hrs)  HEC RAS 5.0  2D Mesh  150 m x 150 m  Terrain  CVFED  1 m resolution  Manning’s n  Based on CVFED  Land Use Jonkman et. al. Jonkman et. al.

1 Breach Zone 0.9 )

D = 1 0.8

0.7 Rapidly Rising/𝐷𝐷 Remaining Zones 0.6 𝐹𝐹 ℎ ln 0.5 = 0.4

0.3 𝐷𝐷 𝑁𝑁 ℎ − 𝜇𝜇 0.2 𝐹𝐹 ℎ Φ Mortality Mortality Fraction (F 0.1 𝜎𝜎

0 0 1 2 3 4 5 6 7 8 9 10 Depth (m)

Remaining Zone Rapidly Rising Zone Central Valley Flood Protection Plan

100

90

80

70

60

50

40 Property Damage (%) 30

20

10

0 0 0.5 1 1.5 2 2.5 3 3.5 4 4.5 5 Depth (ft)

1-story 2-story Split-Level Average  Lacking Bathymetric Data  Downstream Boundary Condition  Delta  Other Rivers   Yolo Bypass  Not a Comprehensive Floodplain  Levees Remain Intact Probable Maximum Flood

Without Auxiliary With Auxiliary Spillway Spillway

Northern Southern Breach Breach

MacDonald Von Thun & MacDonald Von Thun & Gillette Gillette No Breach Floodplain Depth No Breach

(Feet) < 3.3 3.3 - 6.6 6.6 - 9.8 9.8 - 13.1 > 13.1 Floodplain Depth Northern Failure

(Feet) < 3.3 3.3 - 6.6 6.6 - 9.8 9.8 - 13.1 > 13.1 Floodplain Depth Southern Failure

(Feet) < 3.3 3.3 - 6.6 6.6 - 9.8 9.8 - 13.1 > 13.1 Does Not Take Evacuation Into Account

Mortality No Breach

% Mort. of People Remaining Does Not Take Evacuation Into Account

Mortality North Breach

% Mort. of People Remaining Does Not Take Evacuation Into Account

Mortality South Breach

% Mort. of People Remaining Property Damage No Breach Property Damage North Breach Property Damage South Breach  Flooding Without Breach  Varying Flood Paths  High Mortality and Property Damage  American River  Pocket  Natomas