Michael Pantell, E.I.T.

Urban Flood Risk Reduction Study Lathrop/Manteca & SJAFCA

DWR Funded

2015 Existing Conditions

2065 Climate Change

Storm Surge

Sea Level Rise

Global Climate Change Models

Has not been Peer Reviewed

Return Period (Year)

2015 Flow(cfs)

2065 Climate Change Flow

(cfs)Multiplier

10 44,000 48,000 1.09

25 49,000 81,000 1.65

50 65,000 116,000 1.78100 82,000 204,000 2.49200 96,000 310,000 3.23

500 154,000 504,000 3.27

0

20,000

40,000

60,000

80,000

100,000

120,000

140,000

160,000

180,000

200,000

220,000

240,000

260,000

280,000

300,000

320,000

340,000

0 5 10 15 20 25 30 35 40 45 50

Flow

(cf

s)

Time (Days)

Peak 200-Year Flow

HEC RAS 5.0 1D/2D model

Calibrated to 2017 event Verified to 2006 Event

Reviewed by DWR

Created FDA Model

Mossdale Tract Study Area

Lathrop, Manteca & South Stockton

Approximately 65,000 people

Approximately 50,000 structures

6 Index Points

Representative Levee Breaches

Random Flood Event

Annualized Damage/Life Loss

Stage-Frequency Curve

Levee Fragility Curve

Breach Floodplain

Structure Inventory

Damage –Depth Curves

Year Expected Annual Damages

Expected Life Loss

2015 $30,035,000 0.88

2065 $99,405,000 6.48

Under Existing Land Use and Flood Protection System

3 Times the flow in 50 Years Protecting cities will affect other regions Current State and Federal Plans Don’t Address the Issue

Large Investment

Climate Change Predictions Needs Peer Review Small Investment

If Valid, Significant Bypass is Needed