Loading...
3.A Attachment PB_Adaptation Plan_1-9-2020_draft VtY pF City of Pismo Beach Sea Level Rise f �f Draft Adaptation Plan lanuary9, 2020 DUDEK l , COASTAL Sea Level * Adaptation Plan .6 !ik - JA What: An informational document that describes adaptation strategies that can reduce vulnerabilities associated with sea level rise and coastal hazards. Why: To provide a bridging document between information presented in the VA and policies and ordinances included in the update General Plan/Local Coastal Program . Guiding PrinAdaptation M M • Reduce potential for loss of life, health and property from current and future coastal hazards • Promote responsible growth and resilient development, especially in areas exposed to current and future coastal hazards • Preserve environmental resources, access and recreation opportunities along the coast which help make Pismo Beach an iconic tourist destination • Pursue opportunities to increase adaptive capacity of coastal resources through local projects (i.e. Capital Improvement Plan) and regional projects • Account for the uncertainty and probability associated with sea level rise and coastal hazards to develop adaptation strategies that are flexible and account for the risk tolerance of vulnerable coastal resources Adaptation Overview • Protect: General Adaptation Strategies (CCC, 2015) • Engineered structures or other Protect: • measures (beachnourishment) to Hard protection • Soft protection/living shorelines protect resources Accommodate: Protect agricultural barriers for Siting and design standards flood protection • Accommodate: • Retrofit existing structures 5tormwater management date • Modify existing resources& new relocCon-ate over short-term, reloc2te over long-term resou rces to reduce SLR vulnerability Update land din use designations and zoning ordinances • Redevelopment restrictions • Retreat: . Permit conditions Retreat. • Relocation or removal of resources in • Limit new development in hazardous areas and areas adjacent hazard zones to wetlands, ESHA, other habitats • Removal of vulnerable development Promote preservation and conservation of open space Adaptation Planning Horizons Probabilistic SLR Scenarios, OPC (2018) +80 rs 7 y 0.5% Probability "Long-term" Likely Range (upper bound) planning horizon 5 W Likely Range (lower bound) • 50%(Median Projection) 4 +50 yrs 3 "Near-term" +30 rs 2 _ planning horizon y , 0 2030 2040 2050 2060 2070 2080 2090 2100 Planning Horizon Overview of SL hazards described in VA Bluff instability gal Coastal erosion � � w 1) Bluff erosion # # f Wave runup&overtopping + Coastal erosion 2) Shoreline erosion 3) Coastal flooding Flooding of low �a " Dune erosion Pismo Creek lying areas J, Fluvial flooding 6 1 2 Study Areas MWr7Miles 0 City of Pismo Beach San Luis Obispo County 4) Fluvial flooding ' II What magnitudes of SLR matter over the near-term *?. SLR Scenario Key ImpactThresholds 0 ft Development& infrastructure exposed to bluff erosion (Present day) Bluffs Variety of shoreline/bluff stabilization measures in place 0 ft Low-lying Areas Fluvial hazards along Pismo Creek& Meadow Creek (Present day) 1.6 ft Bluffs Coastal squeeze impacts beaches, intertidal and subtidal habitats Reduced opportunityfor access& recreation along pocket beaches 1.6 ft Downtown Partial loss of sandy beach width 1.6 ft Low-lying Areas Coastal storm results in flooding of RV resort Berm closure at creek mouth could increase risk of fluvial hazards Near-term refers tovuInerabiIities projected over then ext 30 years.There is a —2% probabiIitythan SLR will exceed 1.6 feet by2050. What coastal resources are at risk? M I M .- �& • Coastal squeeze impacts beaches & Eldwayen Ocean Park intertidal habitat* • Bluff top development (un-protected) • Infrastructure u n- rotected ` • 50 Stormwater outfalls ---=4 = -- '` - Ocean Blvd & utilities --— _ present conditions intermediate SLR l advanced SLR Loss of Dry Beach No Dry Beach q. Narrow Intertidal No Intertidal x submerged Intertidal Dry Beach Resources become"squeezed"between a non-erodible bluffface and rising sea level r .:r.M j� � �"ti + ;.Yam"' -_�•;' � .y � - • Large areas within present day 100- year floodplain 91 r. J!' w�G SRkljB p RWF No record ofsi significant damages from 5e•wan --� r . e y 2t S I . g g - r ZONE AE (EL 15) (DEL E 'r EFS �qO� Q Pismo Creek flooding �� 4� P ZONE AE.. L�s S� P�+ [EL 14) BFE s range fr m 1 t 1 feet (NAVD) o 3 0 8 ` ,• oos `` stir: Several bridges do not have capacity Z°NElEA. r �• r for the 100-y ear flood ;` '�~` .� ONE AE (EL 15) EL_QNE'E. • Overtopping/road closures and r damage would be expected _ - "1! .'1 r+r.r.,arl Yrur7icf i n Near-term — Planning Measures a dL in • Identify SLR hazard zones • Public outreach and education associated with GP/LCP update • Local Adaptation Planning • General Plan/Local Coastal Program Update • Apply consistent planning & development policies throughout the City • Capital Improvement Plan (CIP) process • Incorporate SLR probability and coastal hazards into existing budgeting & planning process • SLR adaptation strategies can be incorporated into variety of projects • Support Regional Adaptation Planning • Local Hazard Mitigation Plan (LHMP) and Coastal Regional Sediment Management Plan (CRSMP) Near-term — Policy Measures A� • Understand SLR hazards • Identify and use best available science • Develop standards and methods for site-specific coastal hazard analyses • Real estate disclosure of coastal hazard information • Manage development in hazard zones • Siting & design requirements for new development in hazard zones • Managing redevelopment to limit repetitive loss structures • Mitigate coastal hazard impacts • Shoreline & bluff protection devices — evaluation, maintenance and repairs • Maximize protection of coastal resources V ar-term — Project Measures ( Bluffs) • Opportunistic Beach Nourishment • Am_-_ Maintain and improve bluff stabilization in critical areas _ _ • Rocky intertidal habitat restoration gyp- _ �-- �ry :v •��� � ,�R_�-?G-�' 1 1 Near-term — Project Measures ( Downtown )l k on&=- 4 • Maintain and improve shoreline protection in critical areas • Dry floodproofing in high-hazard areas (e.g. Vespera parking garage) • Explore options for beach nourishment 4 e ram= _ ■°° °lt�■�� I. T r 1 'l i / 1 Near-term — Project Measures -lying Areas) AL �� JEEEIEk__ iLl • Deployable flood protection barriers • Critical resources in advance of extreme event ' • Drainage Improvements Q • Low impact development techniques - • Green/pervious surfaces Sliding Lift but • Flood storage & conveyance a �, JU ' 1 1 What of SL matter over the l SLR Scenario Key Impact Thresholds A 3.3 ft Bluffs Loss of pocket beaches&associated resources Increased wave attack along toe of bluffs threatens development& infrastructure 3.3 ft Downtown Roughly half of Pismo State Beach lost Pier deck exposed to wave impacts during extreme event 3.3 ft Low-lying Areas Beach profile migration impacts dunes and Pismo Creekestuary Flooding of RV resort& campground during extreme coastal event 6.6ft + Downtown Daily shoreline against unprotected bluffs&development along Downtown Low-lying Areas Widespread non-storm"high tide"flooding along Pismo Creek Very slight chance (0.5%) SLR exceeds 3.3 feet by 2070 and 6.6 feet by 2100 What coastal resources are at risk in the long -term ? i • 3.3 ft SLR - , � '. vHarrington • Coastal squeeze impacts beaches & - 144 s G access points LL �Q Q • Pier exposure to extreme waves ^ • 6.6 ft SLR 7 • Bluff-top/back beach development • Pier & Plaza Bluff Top +4.9 ft (150 cm) SLR Transportation ® +6.6 ft(200 cm) SLR +3.3 ft (100 cm) SLR ❑ Bus Stops +4.9 ft(150 cm) SLR +1.6 ft (50 cm) SLR 0 City Parking Lots +3.3 ft(100 cm) SLR Q Beach Access Points City Streets +1.6 ft(50 cm) SLR Wastewater Baseline 0 Lift and Pump Stations Shoreline Recreation +6.6 ft(200 cm) SLR = City Facilities 1 1 100-Yr Flood Extents rP.rice ;rrX'+�i ' �� . '� �(� _• r +1.6 ft(50 cm)SLR Street,Park +3.3 ft(100 cm)SLRLow Areas +4.9 ft(150 cm)SLR +6,6 ft(200 cm)SLR = y .E,?A- lying •'r ,�s Shoreline - +6.6 ft(200 cm)SLR r +4.9 ft(150 cm)SLR >y A L eT 1, +3.3 ft(100 cm)SLR 3. +1.6 ft(50 cm)SL0. Q Beach Access Points .. . • • 3.3 ft SLR Wastewater y Lift and Pump Stations ' „•� • � Wastewater � W Flooding of RV resort & �' � �► '�' r -� Transportation - #�.�f. .• - �, ' + .- Oolliver Street Bridge campground o Bus Stops _, ,�• r' ]City Parking Lots i City Streets • Beachprofile/estuarine impacts + Railroad Tracks Recreation 0 City Facilities 6.6 ft SLR Q North Beach Campground �� I"ra Lease. Q Pismo Lake nl' Mary • 100-Year Coastal - r ` '�` Barrington o Widespreadfloodin - ; ,� o g Storm Hazards Park �.` • Development & Infrastructure Downtown and . Low-Lying Area 0 250 500 1,00 Feet Long -term A1 . 1 . 1Strategies A a 16 A • 1 .6 feet of SLR - trigger for long-term adaptation strategies • Evaluate effectiveness of near-term strategies & adjust as appropriate • Bluffs: adjust near-term strategies based on bluff & beach monitoring data • Mitigate adverse impacts to beach access, habitat or other resources • Downtown: develop shoreline management program • Specify adaptation strategies (nourishment/living shoreline) to apply along Downtown waterfront • Low-lying Areas: flood hazard mitigation along Pismo & Meadow Creeks • Coordinate with Caltrans & State Parks • Develop long-term plan for reconfiguration of RV resorts & other resourcesto accommodate 3.3 -6.6 feet SLR ILI xt Steps C � M • Update draft Adaptation Plan — City & CCC comments • Stakeholder/com m unity outreach • King Tides Event — January I I th at 9:00am (Addle St) • Final Adaptation Plan • Develop policies for GPACP Safety Element Ll'olicy Approac (Safety Element) o Broad policies for development in a coastal hazard areas • Applies to properties within Vulnerability Assessment hazard maps • Based on Chapter 3 of the Coastal Act • New development and redevelopment must avoid hazards • Protection is permitted for existing structures, coastal-dependent uses, and public beaches • Includes application requirements (e.g., SLR scenarios, anticipated lifespan ofdevelopment/risk aversion, site-specific hazard assessment) and shoreline protection device requirements (e.g., alternatives analysis, mitigation, monitoring, repair and maintenance) o Threshold-based policies for adaptation utilizing the Adaptation Plan recommendations • Triggered by SLR monitoring • Commitment to pursue long-term adaptive management strategies and programs, specific to location and hazard (e.g., beach nourishment, habitat restoration, flood hazard mitigation and retrofits)