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Home My WebLink AboutStaff Report 14273City of Palo Alto (ID # 14273) Utilities Advisory Commission Staff Report Meeting Date: 8/3/2022 Report Type: VII. NEW BUSINESS City of Palo Alto Page 1 Title: Discussion and Presentation on Sea Level Rise From: Director of Utilities Lead Department: Utilities Recommendation This is a discussion item only and no recommendation is needed. Discussion The City of Palo Alto Utilities Advisory Commission requested a presentation regarding the development status of Palo Alto’s Sea Level Rise Adaptation Plan. At the August 3 UAC meeting Public Works Watershed Protection staff will present an overview of the recently completed Sea Level Rise Vulnerability Assessment, and the forthcoming Sea Level Rise Adaptation Plan goals, framework, and timeline for development. The City completed a Sea Level Rise Vulnerability Assessment (Assessment) which evaluates hazards and risks to City and community assets from increments of sea level rise between 12-84 inches. This is representative of what may occur through the year 2100 based on California Ocean Protection Council Sea Level Rise guidance. The Assessment also discusses the sea level rise-related impacts from rising shallow groundwater. The Assessment will inform the subsequent development of a Sea Level Rise Adaptation Plan (Adaptation Plan) which will address both sea level rise flood susceptibilities and rising shallow groundwater hazards. The goals of the Plan are to 1) protect and expand habitat, 2) protect City and community assets. Engineering, governance and education solutions would be implemented in phases so that the right level of protection is provided at the right time and with the ability to be adapted as the San Francisco Bay and shallow groundwater continue to rise. The general timeline is as follows: •Late summer 2022: o A staff presentation about the results of the Vulnerability Assessment and overview of how the Plan will be developed; o Public release of the Vulnerability Assessment; •Fall 2022: Plan development and community meetings commence; Staff: Julie Weiss City of Palo Alto Page 2 • Winter 2023 request Council approval of the Plan. Development of the Sea Level Rise Adaptation Plan will be closely coordinated with other sea level-rise related projects and planning efforts led by staff and regional partner agencies. The Adaptation Plan will serve as the Sea Level Rise chapter of the City of Palo Alto Sustainability and Climate Action Plan. Attachments: • Attachment A: Presentation www.cityofpaloalto.org/sealevelrise 1www.cityofpaloalto.org/sealevelrise 1 Palo Alto Sea Level Rise Vulnerability Assessment and Adaptation Plan Staff: Julie Weiss ft c1TY OF g'PALO ALTO www.cityofpaloalto.org/sealevelrise 2www.cityofpaloalto.org/sealevelrise 2 Vulnerability Assessment examines asset exposure to 12-84” of sea level rise with: •Daily high tides •100-year storm tides •Shallow and emergent groundwater changes •Report discussion focuses on 36” sea level rise because that is a turning point if no additional action is taken •36” near end of century (2070- 2100) and will continue to increase after 2100 Sea Level Rise Adaptation Plan Development 7 Monit.or ndModify .Ad.,pti'lion M iSUfC<S As Neseded .Adaptatl,on Pllan Devellopment Process 5 ft c1TY OF g'PALO ALTO www.cityofpaloalto.org/sealevelrise 3www.cityofpaloalto.org/sealevelrise 3 City and Community Facilities and Residential Parcels Utilities and Flood Management Emergency Services Natural Resources, Trees & Open SpaceTransportation www.cityofpaloalto.org/sealevelrise 4www.cityofpaloalto.org/sealevelrise 4 Groundwater work peer review by Dr. Kristina Hill, UC Berkeley 0 . PROT CTIO COU CIL C I TY OF PA 0 A TO ISSI N pathways CillMATE INSTI T UTE Sf El ! ~~~~~i SA ~ltA . 1500 £S . UAlV I. 51\1 _ UTE & THIE AQUATIC SCI CE (ENTE _ www.cityofpaloalto.org/sealevelrise 5www.cityofpaloalto.org/sealevelrise 5 San Francisquito Creek “Downstream Project” Construction completed: Fall 2018 Partnership with San Francisquito Creek Joint Powers Authority Agencies c7 ---- www.cityofpaloalto.org/sealevelrise 6www.cityofpaloalto.org/sealevelrise 6 Palo Alto Flood Basin Tide Gate Structure Replacement Project •Construction starts: 2023 •Construction completed: 2027 •Project partners: Valley Water, City of Palo Alto Shoreline II Levee Improvements •Fall 2024: Feasibility study completion •2030: Construction begins •20: Construction completed •Project partners: Valley Water, USACE, Coastal Conservancy, City of Palo Alto ':: ::J OityOf PIIO ~11llSOi>n.:IIIY ( . . • • • SAIER i.-Angnm~ ~"lier ~IJ!!r1U011 ~$11o"1ine 1 s mapdepbs poum al lulUII! Jl!',ll!e 11ll£)111111!nls ~nderoollS!d!m!loo ; II)' 111,o S,,uth Sall Frand!m Say $1M),.liil•, Foa!ilblity $Ir~)' Ph.as,, ii {" ShOtellne 11 • ~ 111i$ tWCI)' 1$ M!~ting llle"' ~etrec,t_i\,e ,new , ,...,. aD<I shomllne lmplU\'am..,n.ts lhal •tll pmwldo FEMA,....,r!<lftsd ll'ood l)lllldlon and poten!lai halJ~at restoratlOll. This Wldy a ' pJl1,neti;hlp ~~en \l$. Amrr CClr:11, ~, Eng;~ VollefWaoe, •nd Ibo OillJ of l'ilo lt!Ci11'1llcb I ra,:<!\S Illa 2019 SAHR u, Scully ' oondud-"li 1)1' lhll San Francl5'l"llo'CN!l!tJoln1 Pn· ... Authod)'. s.,. 1 Sections 2 and S.t fill' mrore, lnfomucioa . • ,..., ·-................... _ ............. . ~ / " .. .. .... - • I ~ .. . ,, www.cityofpaloalto.org/sealevelrise 7www.cityofpaloalto.org/sealevelrise 7 Palo Alto Airport Palo Alto Horizontal Levee Pilot Project Construction starts: Fall 2023 Construction completed: Fall 2025 Byxbee Park Flood Basin San Francisco Bay Palo Alto Baylands Regional Water Quality Control Plant www.cityofpaloalto.org/sealevelrise 8www.cityofpaloalto.org/sealevelrise 8 Other Adaptations Efforts Elevated power distribution equipment at the RWQCP Sea Level Rise School Curricula Thiesc-k!!i50fl!i WCIC' crM ICd m pillUN?f!ih61:] w1ttl tile-Re k>r'lill 'N.llcr auarnv COllltDI PL,nl NliS!Sc ESsa.A: Nila.al R"51KlfOC'S in II «IMII'-a lc,1dl<'I ... OUl<k' ~, ll,r""'ll'! ~ -a local md:m!ll"'od ~ loo S.111 "'""" l>.lfW'<I """""' S111dM1, - In Uf'l~pit111l~ ~ u •~ OI l'iOld-.lllli.! I.I"' U'1tcy k:-.¥n iKIOUi ~ d..-..:111.itng .1nlmi.ll illlld M\iJI rt m6ghl t.Jkc, bu cnsuro bllulutc, al CJlaf'liGin,g SbM,a ,. .es Gl~11~ &C:CtSS Ll::S.!liON Nil~ 1..5.4 0-~r~ ood ftum ~ "WIii COll1J);1f"C o M!tlC5 or lbit.111 ~rc.lilx' rn:ips,. ~mo l~lrttaf1~ r-Nllu1 ff1 11.h 1!) OIi h -~ p,e<cnl and lulurc cl 111c • lll,llHb babltll ,lfOUfld 11K, SIii r,,., ,oR>yTh "111 ""'"""'...,_...h.>, p"",, Q<Cil'hll!OI CllOl>fl" net cl15a1Z """'. mattct, """"'nd l'ol ll>o luture. ACCESS LE S50N Glada:!>Sl HCSSt [SSJC; ~~t c,, [u, ~:,>l)l'ffl• Studcnls, W!II k-.llll o1bout SCG lcwt re;c, ilnd 16 ~ C.._"ltJSCS tr,' onalr,m11 cJ ima. ll'ley ..,11 IIK.'fl roe... Oil local """ k!vot ,,.., p,~~ ®1fi..l.wi l',ft>1 loc..lll f(,, urK ,11r .1~ r " rnut c:ron1 .1 pr htlilf~ • polcntrat sol 'lo crca .11 bctl.'cl l\m1=' lor ooi-shoc:cs. &CCI S~ 11 ~31iON www.cityofpaloalto.org/sealevelrise 9www.cityofpaloalto.org/sealevelrise 9 Sea Level Rise Adaption Plan Goals 1.Preserve and Expand Habitat 2.Protect City and Community Assets and Private Property a)Protect -keep Bay water out (e.g., levee and tide gate) b)Adapt existing infrastructure (e.g., water proofing and raising structures) c)Prepare for Possible Retreat after 2050 (e.g., consider options for assets outboard of levee) Adaptation Strategies www.cityofpaloalto.org/sealevelrise 10www.cityofpaloalto.org/sealevelrise 10 When we need to start planning based on sea level and year. Adaptation actions sequenced into adaptation pathways NO ACTIO:N l EXISTIING, CO: 1 AddNss in and f\loodiing Near Term Conduct toca.l drainage study and alternativ,es analysis Coordinate with Caltrans to acldrcess overflows o· ert offsite runoff by constructing perimeter flood barriers stall pop-up flood barriers a.cross driveways and a. cess points R-se and regrade th!!' parcel in key low points F odproof buildings and access points. Elevate storage eas off ground. lood proof buildings a.nd elevate equipment cc I tall stormwa.ter drainage system, treatment, and new d. charge point onvert ew discharge point to pumped outfall 2 Protect Assets INear Co ordinate w ith drai niage study Consider raising nearby streets, deploying temporary barriers, or constructing perimeter floodwall to divert storm runoff Tenn Remove rubbt.e a.nd debr s along tl-Je shore ine Raise shoreline edge with a new sea.wall Coordinate w ith the pmjl!'ct r,epl.a.ol!'mi!'nt 2080 Sea Level Rise Projections - - - - - - - - - - - - - -Like ly ta 1-in-200 Chance I 2r ___ _._3s,..·"~· ______ .,._s_"·_s....,2_:"_' _______ ,s_,s_"' _____ n-.--·" ___ s_4~:"' I I ■-■-■-■-■-----...... I I I I I I I I I • I 1 11 11111111 _________________________ '"91 ....... ,. ________ ,..s4.., _____ ~------""''-·►~1 l lllll ■■le------------------------.. 11111111 ___ .,. ______ • ______ ,_ _____ ..,.. __ ....... ,. __ ..,. _____________ .. _______ .,.,...:: I 1 11111 1 ■1-------------------------.-; 111••1119------------------------· I Iii I ■Ill ___ .,. ______ __ I I : •••■■•••■■•••■■••11•------.. -----•-"'►11,,11 I I I I I I I I I e I I I I I I • 111••11141--.... ------·-------i------....;-.,; I I I I I I I ' ......... 1,-----.. r.a,,;I •······••1e------.. --------------..i I I f----, ' LEGEND Coastal Defense Actions Planning Actions ature-Based Actions Stormwater Actions ■ Threshold Trigger ,.., Trigger + Lead Tim e Action Implemented 6 Decision Point 6 Strategic Decision Point 1" Alternative Action -Action Effective ➔ End of Action Lifespan + Action continues www.cityofpaloalto.org/sealevelrise 11www.cityofpaloalto.org/sealevelrise 11 Palo Alto Sea Level Rise Vulnerabihty Assessment Prepared for: City of Palo Alto June2022 ~1 PALO ALTO I -· ~ -OF I www.cityofpaloalto.org/sealevelrise 12www.cityofpaloalto.org/sealevelrise 12 11 4 .. 1 1.2 .3 3. 3.2 3.J 3.4 3.,5 4,1 4.2 4.-3 4.4 4.5 5 .. 1 INlRODUCTION ................................................................................................................ 1 Praoject OveNiew and Pullf)OSl8 ........ , ........................ , ........................ , ...................... 1 Conceptual Framewort!(; .............................................................................................. t Organizalion of lhe Vulnerab11ity Assessment .......................................................... 2 HIS1onca1 Se:a Level Rise· relilds ............................................................................. 9, Sea Level Rise Projections .................................................................................... ·10, St1bsid1tmoo ..................................................................................................................... 12 Sh-allow G:rouoowater Rise-..................................................................................... 13 Liquefaction ............................................................................................................ 14 BUILDING ON EXIS,TING POLICIES AND STUDIES ....... , .............................................. 17 Regula(r,cms and Gufdanoe .. , , ........ , ........... ,,,,, ........ , ............. ,, ....... ,., ............. ,, ........ 17 State -... -.-. -----•.... ----------... -. ------..... -----.•. --.. -. ----.... -... -----•..... ------.....• -•• ----....... -----.. --.• -17 R-egio al .................................................................................................................. 18- City .............................................................................................................................. 18, Sea Level Rise Studies. ........................................................................................... 18. ••••. 21 SEA LIEVEL RISE, SHALLOW GROUNDWATER, AND CONTAMINANT MAPP1ING .. 23 Sea Level ·se lmmdatIon Mapp ng ....................................................................... 23 5.1.1 Assu:mplions and Caveats ...................................................................................... 24 5:1.2 Sea Level Rise Map nterpretalion ......................................................................... 25 5 .. 2 Shallow G'roo lldwaler Map.ping .............................................................................. 27 5.2.1 Exisling Conditio:ns .................................................................................................. 28. 5.2.2 F-uhn-e Conditions ................................................................................................... 29, 5.2.3, AssumpUons and Cav.aats ...................................................................................... 29, 5-2.4 Shallow Grnu lldwal.er Map lnlerpmlalion ................................................................. 31 5.-3 Shallow G:roulldwater and Contamination ............................................................... 31 6 ASSET INVENTORY .......................................................................................................... 35 6.1 Data Collection ....................................................................................................... 35 6.2 Asset Inventory Table ............................................................................................. 35 7 ASSESSING VULNERABILITY AND RISK .................................................................... 39 9 7.1 Methodology and Approach ................................................................................... 39 7.1.1 Exposure ................................................................................................................ 40 7.1.2 Sensitivity ............................................................................................................... 40 7.1.3 Adaptive Capacity .................................................................................................. 41 __1_)_U.,_";::" __ .. :::: __ ::-:..,:::-:-::_:-:-: .. -:::: __ ~ ... ,.,,, •• .,.,. .. ~ •.. cc-. ___ --.-................................................................................. 42 8.1 Key Sea Level Rise Vulnerabilities ......................................................................... 43 8.1 .1 Sea Level Rise Vulnerabilities Under No Action Scenario ..................................... 43 8.1.2 8.2 8.2.1 8.2.2 8.2.3 8.2.4 Sea Level Rise Vulnerabilities if a Bayfront Levee is Constructed ......................... 48 Sea Level Rise and Shallow Groundwater Vulnerability Summary Profiles ........... 49 City and Community Facilities and Residential Parcels ......................................... 50 Emergency Response ............................................................................................ 59 Natural Resources and Open Space ...................................................................... 63 Transportation ........................................................................................................ 71 8.2.5 Utilities and Flood Management... .......................................................................... 80 REFERENCES ... ~ •................................................................................................ 100 ATTACHMENTS ............................................................................................................ 106 Shallow Groundwater Assessment and Maps ........................................................... 106 Sea Level Rise Figures.................................. . .......................................................... 159 www.cityofpaloalto.org/sealevelrise 13www.cityofpaloalto.org/sealevelrise 13 Excerpt of City/Community/Residential Property Exposure to Daily High Tide and Storm Tides Table 10. City and Community Facilities and Residential Parcels: Sea Level Rise Exposure Summary from Daily High-Tide Inundation or 100- Year Storm-Tide Flooding Asset Lucy Evans Baylands Nature Center Animal Shelter Municipal Services Center Utility Control Center Baylands Ranger Station Forni.er ITT Property Libraries Boat Launch Water Level HT ST HT ST HT ST HT ST HT ST HT ST HT ST HT +0-inch SLR +12-inch SLR +24-inch SLR CITY FACILITIES +36-inch SLR + 48-inch SLR +66-inch SLR +84-inch SLR www.cityofpaloalto.org/sealevelrise 14www.cityofpaloalto.org/sealevelrise 14 Excerpt of City/Community/Residential Property Exposure to Shallow and Emergent Groundwater Table 11. City and Community Facilit1ies and !Residential Parcels: Sea Lev,el Rise Exposure Summary from Emergent Groundwater Flooding or a High Shallow Groundwater Table Asset Water +0-inch +12-inch +24-1inch t"' +36-inch + 48-inch +166-inch +84-inch Levell SLR SLR SLR I SLR SLR SLR SLR CITY FACILITIES Lucy Evans EG -----✓ ✓ Baylands Nature HG ✓ ✓ ✓ Center -- EG ------- Animal Shelter HG ----✓ unicipal EG ------- Services Center HG ---- Utility Control EG ------- Center HG ----✓ Baylands Ranger EG ------✓ Statton HG -✓ ✓ ✓ - Former ITT EG ---✓ ✓ ✓ ✓ Property HG -✓ ---- EG Mitchell Mitchell Mitchell ----Park Park Park Libraries - HG itchell itchell ,( r ichel11~ -Park Library Park Library .. Park Library --- Cubberley EG --- . ........__ _/ --✓ ----==--Community HG ✓ ✓ ✓ Center -- www.cityofpaloalto.org/sealevelrise 15www.cityofpaloalto.org/sealevelrise 15Current conditions (2022) www.cityofpaloalto.org/sealevelrise 16www.cityofpaloalto.org/sealevelrise 16 Daily high tide with 36 inches sea level rise (c. 2070-2100) Image shows the approximate area for which planning is needed based on current elevations. The image is not intended to indicate that the entirety of the low-lying shoreline areas would simultaneously flood nor does not account for the duration of overtopping or site-specific conditions that could reduce exposure. www.cityofpaloalto.org/sealevelrise 17www.cityofpaloalto.org/sealevelrise 17 Daily high tide with 36 inches sea level rise (c. 2070-2100) Image shows the approximate area for which planning is needed based on current elevations. The image is not intended to indicate that the entirety of the low-lying shoreline areas would simultaneously flood nor does not account for the duration of overtopping or site-specific conditions that could reduce exposure. www.cityofpaloalto.org/sealevelrise 18www.cityofpaloalto.org/sealevelrise 18 City/Community Residential Facilities located inland of US 101, •2,630 residential parcels •Two schools (Palo Verde Elementary and Ohlone •Two senior/disability centers (Palo Alto Housing Corporation and Alta Torre) Natural Resources •Marshes permanently inundated Transition some tidal marsh areas to a different habitat •4,700 trees •90% of golf course •Five parks: Baylands Athletic Fields, Greer, Seale, Ramos, Baylands Preserve, and Byxbee Park Utilities and Flood Control •Regional Water Quality Control Plant •Four stormwater pump stations •Two electrical substations •Natural gas receiving station •14 miles of Fiber Optic network •35 miles drinking water •37 miles sewer •2 pump stations (SFC and Matadero) •2.5 miles of levee •14 miles of Fiber Optic network Daily high tide with 36 inches sea level rise (c. 2070-2100) Image shows the approximate area for which planning is needed based on current elevations. The image is not intended to indicate that the entirety of the low-lying shoreline areas would simultaneously flood nor does not account for the duration of overtopping or site-specific conditions that could reduce exposure. www.cityofpaloalto.org/sealevelrise 19www.cityofpaloalto.org/sealevelrise 19 City/Community Residential •4,400 residential parcels •Two senior/disability centers •Two schools (Palo Verde and Ohlone) •Seven city facilities Emergency Services and Transportation •US 101 •Roads east of Middlefield Road, •36 miles of multi-use trails. •Palo Alto Airport •14 miles of evacuation routes Natural Resources/Parks/Trees •Seven City parks •6,900 trees Utilities and Flood Control: •Regional Water Quality Control Plant •Four stormwater pump stations •Two electrical substations •Natural gas receiving station A 100-year storm tide with 36” of sea level rise (c. 2070-2100) Image shows the approximate area for which planning is needed based on current elevations. The image is not intended to indicate that the entirety of the low-lying shoreline areas would simultaneously flood nor does not account for the duration of overtopping or site-specific conditions that could reduce exposure. 2021 Depth to Groundwater 0~ Menlo, Park fl/ De1pth to Waiter -<Oft ,o 0-2 ft 2 ~.4 ft 4 -6 fl 6 •. ,s ft 8 10ft 10-t-fl IM1tc 1 .,. S r lln P.,r Sho Hne Golf nk!: Ill ii II,, .. j "' Lo Depth to Groundwater with 36” Sea Level Rise . Note: the future depth to groundwater surface shown is based on uniformly increasing the existing groundwater surface with sea level rise. The depth to groundwater represents the highest annual groundwater surface during temporary wet-season groundwater conditions that may occur over hours or days in the near term, with longer durations occurring as sea level increases or if future extreme precipitation events increase in intensity and/or frequency. The future condition maps do not account for groundwater flows to nearby natural streams which may help reduce the groundwater surface in some areas. See additional caveats discussed in the Palo Alto Sea Level Rise Vulnerability Assessment which will be released in Fall 2022. Menlo Park ... N D-epth to Water -<Of't 0-2 ·ft 2-4ft 4 -6ft 6 -Sfl B· 10ft J.Ot-ft \ / I,; S,hQreline P-,.- ,ho rel lne Golf , .. ~ ... .. 0 .c V, z LO Why look at Shallow Groundwater? ~CITY OF ~PALO ALTO Potential Impacts From Rising Groundwater Increased infiltration into sewer pipelines and below- ground utilities Flooding of basements and below-grade structures Foundation and structural damage Uplift of residential structures and smaller buildings Roadway damage (cracking, buckling, sink holes) Increased emergent (above ground) groundwater ~CITY OF ~PALO ALTO www.cityofpaloalto.org/sealevelrise 24 High shallow groundwater within six feet of the surface could expose underground Utilities such as: •17 miles of fiber optic cable •64 miles of water pipelines •Access to more than 300 manholes and 1,000 access vaults •2 miles of sanitary sewer pipeline •2 electrical substations •3 miles recycled water pipeline •SCADA •Natural gas receiving station •RWQCP Additional hazards to City and Community assets could include: •7 parks •Urban forest •Shallow groundwater within six feet of the surface in some residential communities and City facilities •Roads and evacuation routes •Contaminant mobilization if contaminated groundwater sites are not completely remediated •Increased liquefaction susceptibility near the Bay Anticipated Shallow Groundwater Conditions With 36” Sea Level Rise (c. 2070-2100) Note: the future depth to groundwater surface shown is based on uniformly increasing the existing groundwater surface with sea level rise. The depth to groundwater represents the highest annual groundwater surface during temporary wet-season groundwater conditions that may occur over hours or days in the near term, with longer durations occurring as sea level increases or if future extreme precipitation events increase in intensity and/or frequency. The future condition maps do not account for groundwater flows to nearby natural streams which may help reduce the groundwater surface in some areas. See additional caveats discussed in the Palo Alto Sea Level Rise Vulnerability Assessment which will be released in Fall 2022. www.cityofpaloalto.org/sealevelrise 25 Emergent groundwater could occur during wet weather conditions: •Along two miles of water and sanitary sewer pipelines •RWQCP •Airport •One mile of evacuation routes •770 residential parcels •Byxbee Park •360 City-maintained trees •40% of the Baylands Golf Course •One acre of green stormwater infrastructure. Anticipated Emergent Groundwater Conditions With 36” Sea Level Rise (c. 2070-2100) Note: the future depth to groundwater surface shown is based on uniformly increasing the existing groundwater surface with sea level rise. The depth to groundwater represents the highest annual groundwater surface during temporary wet-season groundwater conditions that may occur over hours or days in the near term, with longer durations occurring as sea level increases or if future extreme precipitation events increase in intensity and/or frequency. The future condition maps do not account for groundwater flows to nearby natural streams which may help reduce the groundwater surface in some areas. See additional caveats discussed in the Palo Alto Sea Level Rise Vulnerability Assessment which will be released in Fall 2022. www.cityofpaloalto.org/sealevelrise 26www.cityofpaloalto.org/sealevelrise 26 1) Protect City and habitat (keep water out from above and below) 2) Adapt City and habitat (increase resilience to water) 3) Consider retreat needs after 2050 www.cityofpaloalto.org/sealevelrise 27www.cityofpaloalto.org/sealevelrise 27 1) Protect City and habitat (keep water out from above and below) 2) Adapt City and habitat (increase resilience to water) 3) Consider retreat needs after 2050 •Continue with levee and tide gate improvement plans •Increase groundwater monitoring and expand groundwater waterproofing •Continue habitat restoration in Bay, creeks and upland areas to absorb and slow water •Develop a SLR Plan in 2022 for redundant protection and to address additional specific asset concerns www.cityofpaloalto.org/sealevelrise 28www.cityofpaloalto.org/sealevelrise 28 1) Protect City from SLR inundation and changing groundwater conditions: 2) Adapt natural and built assets to increase resilience: 3) Consider retreat needs after 2050: •Update design criteria/building codes to assume three feet higher groundwater and SLR •Assume higher-risk SLR scenarios for critical infrastructure design •Install backflow prevention and convert stormwater outfalls to pumped outfalls •Design for adaptability •Enhance City’s flood and emergency response capabilities •Incentivize green infrastructure to reduce peak stormwater flows •Convert portions of Baylands trails to raised boardwalks www.cityofpaloalto.org/sealevelrise 29www.cityofpaloalto.org/sealevelrise 29 1) Protect City from SLR inundation and changing groundwater conditions: 2) Adapt natural and built assets to increase resilience: 3) Consider retreat needs after 2050: •Possible relocation of assets outside of levees •Transition Baylands upland areas to transitional wetland/upland habitat www.cityofpaloalto.org/sealevelrise 30www.cityofpaloalto.org/sealevelrise 30 Next Steps Milestone Completed 1.Complete groundwater peer review and release Sea Level Rise and Groundwater Vulnerability Assessment Q2, 2022 2. Public/staff/Commission meetings for SLR Adaptation Plan Development Throughout 2022 and 2023 3. Council approval of SLR Adaptation Plan Q4, 2023 4. Implement Plan and develop related tools and public education Ongoing after Council approval 5. Update SLR Adaptation Plan with SCAP and revised Ocean Protection Council guidelines. Every five years, but with annual workplans. Sign up for report release and meeting information at cityofpaloalto.org/sealevelrise. www.cityofpaloalto.org/sealevelrise 31www.cityofpaloalto.org/sealevelrise 31 Thank you www.cityofpaloalto.org/sealevelrise www.cityofpaloalto.org/sealevelrise 32www.cityofpaloalto.org/sealevelrise 32