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HomeMy WebLinkAboutExecutive Summary of Shoreline Sea Level Rise Study Report Final Draft Shoreline Regional Park Community Sea Level Rise Study Feasibility Report and Capi tal Improvement Program Prepared for The City of Mountain View December 18, 2012 CIP 12-48 Prepared by ESA PWA with AMEC, HDR, SCI, and HT Harvey Final Draft Shoreline Regional Park Community Sea Level Rise Study Feasibility Report and Capital Improvement Program Prepared for The City of Mountain View December 18, 2012 CIP 12-48 Prepared by ESA PWA with AMEC, HDR, SCI, and HT Harvey 550 Kearny Street Suite 900 San Francisco, CA 94108 415.262.2300 www.pwa-ltd.com Los Angeles Oakland Orlando Palm Springs Petaluma Portland Sacramento San Diego Santa Cruz Seattle Tampa Woodland Hills D120470.001 City of Mountain View City of Mountain View Shoreline Regional Park Community i ESA / Project No. D120470 Sea Level Rise Study December 18, 2012 Table of Contents Executive Summary ................................................................................................................................ ES-1   ES-1. Study Purpose and Background .............................................................................................. ES-1   ES-2. Study Criteria .......................................................................................................................... ES-1   ES-2.1. Baseline Conditions ................................................................................................... ES-1   ES-2.2. South Bay Salt Pond (SBSP) Restoration Project ..................................................... ES-2   ES-2.3. Sea Level Rise Scenarios ........................................................................................... ES-2   ES-2.4. Design Criteria for CIP projects ................................................................................ ES-3   ES-3. Flood Assessment Methods .................................................................................................... E S-3   ES-3.1. Previous Studies ........................................................................................................ ES-3   ES-3.2. Vulnerability Assessment Methods ........................................................................... ES-4   ES-4. Sea Level Rise Vulnerabilities ................................................................................................ ES-5   ES-5. Recommended Adaptation Projects ........................................................................................ ES-6   ES-6. Cost Estimates ........................................................................................................................ ES-8   ES-7. Project Prioritization and Phasing .......................................................................................... E S-9   1  Introduction ............................................................................................................................................ 1   1.1  Study Purpose ............................................................................................................................... 1   1.2  Background ................................................................................................................................... 1   2  Study Criteria ......................................................................................................................................... 3   2.1  Baseline Conditions ...................................................................................................................... 3   2.2  South Bay Salt Pond Restoration Project ..................................................................................... 3   2.3  Sea Level Rise Scenarios .............................................................................................................. 4   2.4  Design Criteria for CIP Projects ................................................................................................... 5   2.4.1  Coastal ............................................................................................................................. 5   2.4.2  Fluvial .............................................................................................................................. 5   2.4.3  Interior Drainage .............................................................................................................. 6   2.4.4  Geotechnical .................................................................................................................... 7   2.5  Evaluation Criteria ........................................................................................................................ 7   3  Flood Assessment Methods .................................................................................................................... 9   3.1  Previous Studies ........................................................................................................................... 9   3.1.1  FEMA Flood Mapping .................................................................................................... 9   3.1.2  USACE Flood Mapping .................................................................................................. 9   3.2  Vulnerability Assessment ........................................................................................................... 11   3.2.1  Coastal Flooding ............................................................................................................ 1 1   3.2.2  Fluvial Flooding ............................................................................................................ 1 3   3.2.3  Interior Drainage ............................................................................................................ 14   3.2.4  Geotechnical Methods ................................................................................................... 15   4  Shoreline Vulnerability to Sea Level Rise ........................................................................................... 16   4.1  Coastal Flooding ......................................................................................................................... 19   4.1.1  West Side City Boundary (Palo A lto Flood Basin & Adobe Creek) ............................. 19   City of Mountain View City of Mountain View Shoreline Regional Park Community ii ESA / Project No. D120470 Sea Level Rise Study December 18, 2012 4.1.2  Coast Casey North Levee .............................................................................................. 19   4.1.3  High Ground Along North Side of Landfill .................................................................. 20   4.1.4  Lower Permanente Creek .............................................................................................. 20   4.1.5  High Ground North of Golf Course Facilities ............................................................... 21   4.1.6  Lower Steven s Creek ..................................................................................................... 21   4.1.7  Sailing Lake Access Road ............................................................................................. 22   4.2  Stormwater Drainage .................................................................................................................. 22   4.2.1  Pump Stations ................................................................................................................ 23   4.2.2  Gravity Outfalls ............................................................................................................. 23   4.3  Recreational Facilities and Ha bitat Mitigation Sites .................................................................. 24   4.3.1  Sailing Lake Intake Pump Station ................................................................................. 24   4.3.2  Charleston Slough Mitigation Site................................................................................. 25   4.3.3  Mountain View Tidal Marsh and Stevens Creek Tidal Marsh Mitigation Sites ............ 26   5  Adaptation CIP Projects ....................................................................................................................... 28   5.1  Overview .................................................................................................................................... 28   5.2  Project Approaches to Managing Uncertainty ............................................................................ 29   5.3  CIP Project Descriptions ............................................................................................................ 30   1. Charleston Slough and Palo Alto Fl ood Basin Levee Improvement ............................. 30   2. Coast Casey North Levee Improvement ........................................................................ 30   3. North Landfill Erosion Protection ................................................................................. 31   4. Lower Permanente Creek Levee and Floodwall Improvements .................................... 32   5. Golf Course Facilities High Ground Augmentation ...................................................... 32   6. Lower Stevens Creek Levee Improvements .................................................................. 33   7. Coast Casey Pump Station Improvement ...................................................................... 33   8. Lower Permanente Creek Storm Drain Impr ovements (with New Pump Stations) ...... 34   9. Sailing Lake Access Road Improvement ....................................................................... 35   10. Sailing Lake Intake Pump Station Modification ........................................................... 35   11. Charleston Slough Tide Gates Improvement ................................................................. 37   6  Cost Estimates ...................................................................................................................................... 38   6.1  CIP Project Cost Estimates ......................................................................................................... 38   6.2  Potential Funding Sources .......................................................................................................... 42   6.2.1  Local Grants and Programs ........................................................................................... 42   6.2.2  State Grants and Programs ............................................................................................ 42   6.2.3  Federal Grants and Programs ........................................................................................ 43   7  Project Prioritization and Phasing ........................................................................................................ 45   8  References ............................................................................................................................................ 49   9  List of Preparers ................................................................................................................................... 51   10  Figures .................................................................................................................................................. 52   City of Mountain View City of Mountain View Shoreline Regional Park Community iii ESA / Project No. D120470 Sea Level Rise Study December 18, 2012 List of Tables Table ES - 1  Vulnerability of Flood Management Elements ........................................................... ES-11   Table ES - 2  Vulnerability of Shoreline Recreational Facilities and Habitat Mitigation Sites ........ ES-12   Table ES - 3  CIP Project Cost Estimate Summary .......................................................................... ES-13   Table ES - 4  Project Cost Estimate Summary with the SBSP Restoration Project ......................... ES-14   Table ES - 5  CIP Project Prioritization and Impl ementation Considerations .................................. ES-15   Table ES - 6  CIP Implementation Timeline..................................................................................... ES-17   Table 1  Summary of Creek Flood Design Criteria From Different Agencies ........................................ 6   Table 2  Summary of Interior Drainage Design Criteria From Different Agencies. ............................... 6   Table 3  Coastal Hydraulic Analysis Elevations and Heights, in feet NAVD....................................... 13   Table 4  Vulnerability of Flood Management Elements ....................................................................... 18   Table 5  Vulnerability of Shoreline Recreational Facilities and Habitat Mitigation Sites .................... 19   Table 6  Lower Stevens Creek Levees Geotechnical Assessment ........................................................ 22   Table 7  Pump Stations, Areas Served, and Receiving Waters ............................................................. 23   Table 8  Gravity Outfalls, Areas Served , and Receiving Waters .......................................................... 24   Table 9  Restoration Site Accretion Rates ............................................................................................. 36   Table 10  Relative Costs for Project Cost Estimate Line Items .............................................................. 38   Table 11  CIP Annual Operating Budget Estimate .................................................................................. 39   Table 12  CIP Project Cost Estimate Summary ....................................................................................... 40   Table 13  CIP Project Cost Summary with the SBSP Restoration Project .............................................. 41   Table 14  CIP Project Prioritization and Im plementation Considerations .............................................. 46   Table 15  CIP Implementation Timeline ................................................................................................. 4 8   City of Mountain View City of Mountain View Shoreline Regional Park Community iv ESA / Project No. D120470 Sea Level Rise Study December 18, 2012 List of Figures Figure ES - 1  Project Area – Existing Flood Management Elements ............................................... ES-18   Figure ES - 2  FEMA Special Flood Hazard Areas ........................................................................... ES-19   Figure ES - 3  Project Area Vuln erabilities ........................................................................................ ES-20   Figure ES - 4  SLR Inundation Map (Without Project) ..................................................................... ES-21   Figure ES - 5  Proposed CIP Projects ................................................................................................ ES-22   Figure ES - 6  SLR Inundation Map (With Project) ........................................................................... ES-23   Figure ES - 7  Charleston Slough, Palo Alto Flood Basin, and Coast Casey Area Project Detail ..... ES-24   Figure ES - 8  Lower Permanente Creek Project Detail ..................................................................... ES-25   Figure ES - 9  Golf Course Facilities High Ground Au gmentation Project Detail ............................ ES-26   Figure ES - 10  Lower Stevens Creek Levee Improvement Project Detail .......................................... ES-27   Figure 1  Project Area – Existing Flood Management Elements ............................................................ 53   Figure 2  FEMA Special Flood Hazard Areas ........................................................................................ 54   Figure 3  Project Area Vu lnerabilities .................................................................................................... 55   Figure 4  SLR Inundation Map (Without Project) .................................................................................. 56   Figure 5  Proposed CIP Projects ............................................................................................................. 57   Figure 6  SLR Inundation Map (With Project) ....................................................................................... 58   Figure 7  Charleston Slough, Palo Alto Flood Basin, and Coast Casey Area Project Detail ................. 59   Figure 8  Lower Permanente Creek Project Detail ................................................................................. 60   Figure 9  Golf Course Facilities High Ground Augmentation Project Detail ......................................... 61   Figure 10  Lower Stevens Creek Levee Improvement Project Detail ...................................................... 62   Attachments Attachment A CIP Proposal Forms Attachment B Comparison of Sea Level Rise Projections Attachment C Coastal Flood Assessments Attachment D Fluvial Flood Assessments Attachment E Stormwater Drainage Assessments Attachment F Geotechnical Assessments Attachment G Cost Estimates Attachment H Project Alternatives Attachment I Funding Evaluation City of Mountain View City of Mountain View Shoreline Regional Park Community ES 1 ESA / Project No. D120470 Sea Level Rise Study December 18, 2012 Executive Summary ES-1. Study Purpose and Background The Shoreline Regional Park Community (Shorelin e Community) Sea Level Rise Study Feasibility Report and Capital Improvement Program (CIP) presen ts a program to address long-term flood protection from sea level rise (SLR) for the City's Shoreline Co mmunity. This document provides of an overview of Shoreline Community vulnerability to sea level ri se, proposed projects to provide long-term flood protection, and estimates of future fund ing needed to implement these projects. The Shoreline Community (Figure ES - 1) is generally bounded by Highway 101 to the south, San Francisco Bay to the north, San Antonio Road to th e west, and Stevens Creek to the east. Within the Shoreline Community are several large high-technol ogy corporate campuses and suburban-type office parks, some residences, recreational facilities, closed landfills, and habitat mitigation sites. The Shoreline Community is subject to coastal flooding from the Bay, overflow from the Palo Alto Flood Basin, and fluvial flooding from Permanente and Stevens Creeks in the 1% (also known as the 100-year) flood event (Figure ES - 2). The proposed CIP projects address the potential effects of SLR on coastal flooding of the Bay shoreline, flooding for some distance upstream of the Bay in creeks that drain to the bay (backwater effects), and on interior stormwater drainage. Th ese projects would protect the Shoreline Community’s buildings, public infrastructure, parks, and other r ecreational amenities important to local residents. The City of Mountain View retained ESA PWA in Ju ly, 2012, to prepare the Shoreline Community Sea Level Rise Study Feasibility Report and Ca pital Improvement Program (CIP). ES-2. Study Criteria ES-2.1. Baseline Conditions Baseline conditions for this Study assume existing site conditions plus implementation of the Permanente Creek flood protection project (SCVWD, 2012). The Perm anente Creek project is currently underway and has an anticipated completion date of 2016. The Pe rmanente Creek project includes raising floodwalls and levees along Permanente Creek and increased upstr eam flood detention at three sites, Rancho San Antonio, Cuesta Park 1 , and McKelvey Park. Baseline conditions are intended to approximate conditions in the year 2017, approximately when the earliest proposed CIP projects would be implemented. The planning horizon extends 50 years to 2067. Future baseline conditions assume that flood protectio n projects in the vicinity – the Palo Alto Flood Basin, Permanente Creek, Stevens Creek, are maintain ed in approximately their current configurations 1 While Cuesta Park was a part of the original project at the time this study took place, Cuesta Park is currently removed from the Permanente Creek flood c ontrol project (SCVWD, 2012). City of Mountain View City of Mountain View Shoreline Regional Park Community ES 2 ESA / Project No. D120470 Sea Level Rise Study December 18, 2012 and levee heights, and thus become susceptible to more frequent flood overtopping with SLR. The City’s wetland mitigation sites are assumed to be maintained in approximately their current configurations. The South Bay Salt Pond (SBSP) Restoration Project is not implemented under baseline conditions. In the absence of the SBSP Restoration Project, the US Fish and Wildlife Service (USFWS) has identified the salt pond levees bayward of the study area as high priority to be maintained (EDAW et al., 2007). Although the pond levees were built for salt producti on and are not accredited by FEMA, they afford some level of flood protection for the Study area. Like the future No Project Alternative defined for the SBSP Restoration Project (EDAW et al., 2007), the baseline assumes that the USFWS would continue to maintain the outboard pond levees in approximately th eir current state and would repair them if they failed. With SLR, the frequency of levee failure ma y increase, increasing the frequency of high energy wave events with the potential to erode the existing levee and landfill slopes. ES-2.2. South Bay Salt Pond (S BSP) Restoration Project The SBSP Restoration Project proposes to restore tidal habitat in former salt ponds located bayward of the developed Study area by breaching the pond lev ees and constructing new flood protection features landward of the ponds. The SBSP Restoration Project is committed to providing flood protection that meets FEMA requirements (EDAW et al., 2007). The SBSP Restoration Project proposes to create a gently-sloped upland habitat transition area along the bayward levee slope, between the Shoreline Community and the ponds. The upland transition will pr ovide habitat for marsh wildlife during high tide as well as wave energy attenuation and additional levee cross-section to enhance flood protection. If feasible, the SBSP Restoration Project also proposes to include the City of Mountain View’s wetland mitigation site Charleston Slough in the tidal restoration. The SBSP Restoration Project is considered in the proposed CIP projects. The SBSP Restoration Project and the City of Mountain View would coordinate in planning and implemen ting any SBSP Restoration Project actions that affect the Study area. ES-2.3. Sea Level Rise Scenarios In March 2011, the California Ocean Protection Co uncil (OPC) published a resolution recommending that state agencies incorporate the ri sks posed by SLR into project and program plans (OPC, 2011). The guidance provided in the State resolution, which applies to projects funded by the state or on state property, is considered the standard for sea level rise planning in California and has been adopted for this Study. The OPC (2011) provides guidance to:  Assess vulnerabilities over a range of SLR projec tions, including analysis of the highest SLR values presented in the state guidance document; and  Avoid making decisions that would result in high risk. City of Mountain View City of Mountain View Shoreline Regional Park Community ES 3 ESA / Project No. D120470 Sea Level Rise Study December 18, 2012 Because of considerable uncertainty in sea level ri se projections, this study adopts two sea level rise scenarios to bracket the low and high ends of a re presentative uncertainty range. The two sea level rise scenarios are:  8 inches of sea level rise between 2000 and 2067  31 inches of sea level rise between 2000 and 2067 These scenarios are from a recent report from the Na tional Research Council (NRC 2012), expected to be adopted as official state guidance. The values are adjust ed to local site conditions and are similar to those used in the ongoing US Army Corps of Engineers (USACE) South San Francisco Bay Shoreline Study (SSFB Shoreline Study). The 2067 timeframe represe nts the planning horizon for this Study. Since current information for the San Francisco Bay area do es not provide consensus on whether the severity of local storms will change as a result of climate cha nge, this study does not consider changes to storm runoff intensity and frequency. ES-2.4. Design Criteria for CIP projects Levee design criteria were developed in consulta tion with SCVWD staff to comply with SCVWD requirements, which meet, but are slightly more c onservative than FEMA requirements. From a hydraulic perspective, this requires that coastal an d creek levees provide adequate freeboard 1 and do not fail during the 1% flood event. These design criteria are similar to those used for a proposed project to the north on San Francisquito Creek. To the south, the USACE is applying a risk-based appro ach that quantifies risk and uncertainty and enables quantified risk/cost tr adeoffs. Although different in its methodology, the resulting flood protection is expected to be simila r to FEMA requirements. Compliance with these criteria could be used to justify a modification of the fl ood map that removes properties and development from the floodplain, and also alleviates requirements for flood insurance as well as building restrictions to mitigate flood damages. A more detailed analysis w ould be required to ascertain whether there is a Federal Interest in funding a portion of the lev ee construction (such as through the SSFB Shoreline Study), and the design level of flood protection (e.g . levee crest elevation) that could be funded. ES-3. Flood Assessment Methods ES-3.1. Previous Studies Existing FEMA studies indicate that much of the City ’s Shoreline Community is exposed to coastal flood hazard, as indicated by FEMA’s mapping of the 1% annual chance floodplain (Figure ES - 2). Although the salt pond levees provide some degree of prot ection from coastal flooding, these levees are not certified by FEMA. The levees are not certified because their crest elevation is below the 1% water level freeboard requirements and they likely do not meet geotechnical specifications. Since the levees lack certification, FEMA considers the levees to fail at st opping or reducing the inland propagation of the 1% 1 Freeboard is an increment to the leve e elevation above the design water level to increase the likelihood of the design flood event being contained without the levee ove rtopping. Freeboard provides a buffer to a ccommodate uncertainty in the estimated design flood event. City of Mountain View City of Mountain View Shoreline Regional Park Community ES 4 ESA / Project No. D120470 Sea Level Rise Study December 18, 2012 still water level. As a result, most of area mapped as vulnerable to flooding occurs where the land surface within the Shoreline Community is below the 1% s till water level for the Bay. A small portion of flooded area west of Permanente Creek and south of Charle ston Road is mapped as a fluvial flood hazard area. FEMA flood hazard zones do not include future condi tions such as future sea level rise. FEMA is currently revising its coastal flood maps for the Ba y. We anticipate that the area mapped into the floodplain is likely to increase in area, inundation depth, and possibly destructive power. The SSFB Shoreline Study has also evaluated flood risk for the City’s shoreline. The USACE flood assessment methodology is different than FEMA’s, partic ularly in the treatment of levee failure and the addition of sea level rise. In contrast to FEMA’s assu mption that uncertified levees fail to affect the 1% still water level, the USACE met hodology assesses levee failure probabilis tically, thereby assigning some degree of levee effectiveness in reducing inland pr opagation of flooding. The resulting flood levels developed using USACE’s methods can be substantially different than those developed using FEMA’s methods, with USACE’s methods predicting less ex tensive inundation than FEMA’s method. The SSFB Shoreline Study is being performed by the USACE t ogether with local sponsors to recommend one or more projects for Federal funding. The USACE is co nsidering projects that will reduce flood risk and restore ecosystems. The flood risk assessments include sea level rise, with an upper bound of 36” by 2067. The SSFB Shoreline Study is currently focused on the area around the Town of Alviso in the far south San Francisco Bay. The Mountain View shoreline is not currently being evaluated as a priority area in the SSFB Shoreline Study, though the most rece nt publically-available flood modeling (USACE July 2010 as modified by errata August 2010) shows some flooding west of Permanente Creek for the high SLR scenario. We understand that flood modeling me thods have changed as the modeling has been refined for the Alviso area (Frank Wu, pers. comm.). Future assessments of the Mountain View area could result in updated risk assessments. ES-3.2. Vulnerability Assessment Methods The Shoreline Community SLR Study used one-dim ensional hydraulic modeling, two-dimensional hydraulic and wave modeling, and analytical met hods to assess the potential effects of SLR on coastal flooding of the Bay shoreline, flooding along Permanente and Stevens Creeks, and on interior stormwater drainage. In accordance with FEMA guidelines, the coastal flood vulnerability assessment considered both still water level (SWL) and total water level (TWL). SWL is the base elevation which does not include waves and associated wave-driven processes. TWL is th e sum of SWL, wind setup and wave runup. The analysis presumes that the salt pond levees are sufficien tly intact to block waves from San Francisco Bay. If this is not the case, the waves and wave runup 1 conditions used to design the new levees would be greater. ESA PWA modeled 1% water leve ls on Permanente Creek and Stevens Creeks using HEC-RAS, a USACE-developed model that is certified for FEM A flood evaluations. Existing HEC-RAS models for both creeks were provided by Santa Clara Valley Wate r District (SCVWD) and modified to include SLR 1 ‘Wave runup’ is the uprush of water from wave action impinging on the shoreline. City of Mountain View City of Mountain View Shoreline Regional Park Community ES 5 ESA / Project No. D120470 Sea Level Rise Study December 18, 2012 downstream boundary conditions for this study. This st udy tested two pairs of discharge and tidal water level to estimate the 1% event: 1% discharge paired with 10% tidal water level and 10% discharge paired with 1% tidal water level, per SCVWD guidance. Afte r simulating both of these pairs, the 1% water level throughout the model domain was defined at each point as the higher predicted by the two pairs. The 1% discharge yields the higher water level in the upstrea m portion while the 1% tidal water level yields the higher water level in the downstream portion. The switch between these two controlling event occurs several thousand feet upstream of wh ere the creeks enter the salt ponds. The study area interior drainage system contains sever al pump stations and gravity outfalls that discharge to Stevens Creek, Permanente Creek, the Palo Alto Flood Basin, and the Mountain View Tidal Marsh. The pump station and gravity storm drain outfall locati ons were first compared with the results of the hydraulic models developed for Stev ens and Permanente Creeks to determ ine if the outfall locations were susceptible to the impacts of sea level rise under the low and high SLR scenarios analyzed. For pump station outfalls falling within the portion of the creek system expected to be impacted by SLR, the pump curves for the pump stations were analyzed to assess impacts to performance and loss of pumping capacity. Changes in total dynamic head resulting from the increased discharge water surface elevations and the associated decrease in pumping capacity resulti ng from this increased head were analyzed. For the gravity outfalls discharging to the portion of the creek system expected to be impacted by SLR, the drainage systems were analyzed for the potential of reverse flow and flooding propagating upstream from the creeks. Note that the current study did not assess th e storm drain systems’ capacity to handle the 1% interior drainage hydrograph. No hydraulic modeling was performed for the gravity outfalls since storm drain geometry, hydrology and hydraulic basis of design conditions, and uns teady models were not available. The parking lots, adjacent roads, and adj acent structures have finished grades and elevations lower than the sea level rise projections for the co astal areas and the resulting water surface elevations within the creeks. Therefore, vulnerability due to reverse flow was assessed based on these elevation differences. ES-4. Sea Level Rise Vulnerabilities Table ES - 1 provides a summary of SLR vulnerabilit y by flood management element – organized by coastal flood defense, stormwater pump stations, and st ormwater gravity outfalls – for the 1% flood event. Many of the coastal flood defense elements are vulne rable to 1% flooding under baseline conditions and become more vulnerable with SLR. All of the interi or drainage elements are not vulnerable to flooding from the creeks’ 1% flood event under baseline a nd low SLR conditions, with the exception of the Michael’s Parking Lot #1 and #2 Outfalls, which ar e vulnerable under baseline conditions. In addition, several gravity outfalls and one pump station are subject to flooding under high SLR conditions. Figure ES - 3 presents the vulnerability graphically, with color coding used to represent the extent of vulnerability to 1% flooding for increasing SLR. Featur es shown in red are vulne rable to flooding under baseline conditions, features shown in orange are vul nerable under low SLR conditions, features shown in yellow under high SLR conditions, and features shown in green do not flood under high SLR conditions. Figure ES - 4 presents inundation mapping for th e Shoreline Study area under low and high SLR scenarios. The 1% still water level tidal boundary co ndition for each scenario was used in developing the mapping. For the low SLR scenario, 8” was added to the baseline 1% water level, yielding 11.3 ft City of Mountain View City of Mountain View Shoreline Regional Park Community ES 6 ESA / Project No. D120470 Sea Level Rise Study December 18, 2012 NAVD88 1 ; for the high SLR scenario, 31” was added to th e baseline 1% water level, yielding 13.2 ft NAVD88. These inundation areas extend further than ex isting FEMA flood zones, primarily because they include sea level rise whereas FEMA only considers present day conditions. While USACE flood assessments include sea level rise, th ey also assume that a greater degree of flood protection is provided by the uncertified levees. Therefore, the USACE asse ssments predict smaller flooding extent than both FEMA and this study. Also note that the flood modeling methods employed by the USACE to assess Mountain View flood risk have since been revised, but not applied to the Mountain View shoreline. Future assessments of Mountain View flood risk with the revised methods could result in updated risk assessments. SLR vulnerability for the Shoreline Community recrea tional facilities and the City’s near-shore habitat mitigation sites is described qualitatively in Table ES - 2. For the City’s mitigation sites, Charleston Slough and Stevens Creek Marsh are most vulnerable to SLR, since muted tidal flows through culverts limit the delivery of estuarine sediments necessary for raising the marsh with SLR. ES-5. Recommended Adaptation Projects Eleven CIP projects were developed to address the vul nerabilities identified in this study. The projects were defined after consideration of a range of alternative sea level rise conditions, flood protection alignments, and types of improvements, such as levees and floodwalls. The selection of recommended alternatives was based largely on existing flood mana gement infrastructure, cost effectiveness, and consistency with adjacent sen sitive wetland habitats. The proposed CIP projects, shown in Figure ES - 5, remove the developed and recreational areas from 1% flood inundation. The resulting inundation extents w ith the CIP projects implemented are mapped in Figure ES - 6. The CIP projects are listed below and shown in figures as indicated. Note that the projects are numbered according to an east-west conve ntion and not on a priority basis. 1. Charleston Slough and Palo Alto Flood Basin Levee Improvement . (Figure ES - 7) Design, permit, and construct improvements to a 6,600 -ft section of levee that separates Charleston Slough and the Palo Alto Flood Basin. The levee improvements include raising the crest elevation and providing erosion protection. Because of th e shared risk across local government boundaries at the Palo Alto Flood Basin, this aspect of the City of Mountain View’s flood exposure is best managed through City participation in a re gional planning effort and cost sharing. 2. Coast Casey North Levee Improvement. Design, permit, and construct coastal flood levee improvement to help protect property in the City’s northwest corner from flooding caused by San Francisco Bay. The levee will extend 1,300 feet from the high ground of the City’s Shoreline Park landfill to the City’s boundary with Palo Alto. 3. Landfill Erosion Protection. Design, permit, and construct erosion protection for the levees on the north side of the East and West Landfill. 4. Lower Permanente Creek Levee and Floodwall Improvements. (Figure ES - 8) Design, permit, and construct flood protection measure s to protect property along lower Permanente 1 North American Vertical Datum 1988 is a surv eying benchmark for el evation measurements. City of Mountain View City of Mountain View Shoreline Regional Park Community ES 7 ESA / Project No. D120470 Sea Level Rise Study December 18, 2012 Creek. The measures consist of raising crest el evations for multiple levee sections (combined length – approximately 2,500 ft), constructing one new floodwall (length – approximately 700 feet), and raising the crest elevation of th ree other floodwall sections (combined length – approximately 650 ft). 5. Golf Course Facilities High Ground Augmentation. (Figure ES - 9) Design, permit, and construct engineered fill to the north of the C ity-owned golf course facilities and North Shoreline Boulevard and south of the Mountain View Ti dal Marsh to provide flood protection for golf course facilities including buildings, sanitary sewer lift station, parking lots, and roadway. 6. Lower Stevens Creek Levee Improvements. (Figure ES - 10) Design, permit, and construct levee improvements along lower Stevens Creek, north of Crittenden Lane. The improvements consist of improvements to existing levees, a short section of new levee with drainage culverts, as well as levee access and maintenance elements. 7. Coast Casey Pump Station Improvement. Design and construct a project to improve pump station capacity at the Coast Casey Stormwater Pump Station to counter sea level rise impacts on pump station hydraulics. Note that if flood prot ection improvements are implemented for the Palo Alto Flood Basin, a portion of which is describ ed in CIP #1 above, then the Coast Casey Pump Station improvement may not be necessary. 8. Lower Permanente Creek Storm Drain Improvements. Design and construct the realignment of storm drain systems and the installation of three pump stations to evacuate interior drainage from the storm drains to lower Permanente Creek. 9. Sailing Lake Access Road Improvement. Design, permit, and construct a buttress fill on the west side of the Sailing Lake access road. The f ill provides additional slope stability to resist failure due to heavy vehicle traffic and limits seepage through the levee under the road, which helps contain the Sailing Lake. 10. Sailing Lake Intake Pump Station Modification. Design, permit, and implement alterations to the Sailing Lake Pump Station to adapt the pum p station, intake, and suction and discharge piping. 11. Charleston Slough Tide Gates Improvement. Revise Inner Charleston Slough tide gate operations to maintain water le vels within targeted range. The projects are presented with the City’s CIP proposal template in Attachment A. For projects dependent on the magnitude of sea level rise for their design, three alternatives are presented:  Low SLR –1% flood protection with 8” of sea level rise  Low SLR ‘Plus’ –1% flood protection with 8” of sea leve l rise, but with a broader base sized for the high SLR scenario so additional fill can be more easily added at later time  High SLR –1% flood protection with 31” of sea level rise The projects are defined at a concept screening level. We anticipate that the projects will be refined and may change during subsequent planning and design, pa rticularly as integration with the SBSP Restoration Project and other regional projects evolves. Because of the need to coordinate with other projects, such as the South Bay Salt Ponds and regional flood planning, as well as the evolving projections of sea level rise, another sea level rise assessment is also recommended after another decade has passed. City of Mountain View City of Mountain View Shoreline Regional Park Community ES 8 ESA / Project No. D120470 Sea Level Rise Study December 18, 2012 Implementation of the SBSP Restoration Project o ffers opportunities to integrate the City’s flood management strategy with ecological restoration. Th is integration can benefit the proposed CIP projects by providing opportunities for cost sharing, improved public access, and, wetland mitigation credit. It would change how several of the CIP projects are im plemented and make improvements to the Charleston Slough tide gates (CIP #11) unnecessary. The CIP pr oject proposals identify how each project may change to integrate with the restoration. ES-6. Cost Estimates A summary of the proposed adaptation projects’ cost s is presented in Table ES - 3. The estimated total cost is $43-$57 million in 2012 dollars. Total cost s are similar with implementation of the SBSP Restoration Project (Table ES - 4), though $27-$3 2 million of improvements also benefit the SBSP Restoration Project and have the potential to be cost shared. The estimated annual operating budget associated with the new infrastructure is approxima tely a one third engineer position, a full time maintenance position, and $117,0 00-130,000 in expenses. Since the CIP projects are in the planning stage a nd an engineering design has not been completed, a number of assumptions were made and the cost estimate is very approximate. General costs for mobilization, design, project management, constructi on inspection, and administration were added based on a percentage of the construction costs. The cost estimate does not include right-of-way easements or property acquisition costs. The cost estimates are based upon a concept screeni ng level of design and include a 20% construction contingency and an additional 10% contingency for overall project costs. Note that the accuracy of the cost estimate (-50% to +100%) is for the extent of construction described in the CIP proposal project descriptions. According to the AACE International cost estimate classification system, this is a Class 4 cost estimate, which is characteristic of a 1% -15% level of project definition and suitable for a feasibility study such as this one. There is additional uncertainty associated with future desi gn refinements that result in a greater or lesser extent of construction than assumed, particularly for the levee components. The strategy for meeting the funding needs of th e Shoreline Community SLR CIP projects will likely include a combination of funding approaches. Subject to Shoreline Community Board (Mountain View City Council) approval, the Shore line Regional Park Community may commit a portion of its unassigned, unrestricted net assets to the CIP projects. For many of the projects, a combination of funding would be appropriate from the Shoreline Community, local funding initiatives, as well as regional, State and Federal grants and programs. The FloodSafe Califor nia Local Levee Assistance Program provides for feasibility studies, geotechnical evaluation, design an d repair of critically-damaged levees and structures to reduce flood risk. This State program generally requires a 50% cost share. The Federal government provides funding for projects with a flood protecti on purpose, such as the SSFB Shoreline Study. As noted above, the Mountain View shoreline is not currently identified as a priority area in the SSFB Shoreline Study, though this is subject to change in future assessment. Funding through the SSFB Shoreline Study will be directed first to those areas th at have been identified as the highest priority. For flood protection projects, the USACE pays 50% of th e cost for feasibility studies and up to 65% for City of Mountain View City of Mountain View Shoreline Regional Park Community ES 9 ESA / Project No. D120470 Sea Level Rise Study December 18, 2012 construction. The USACE does not cost-share for ope rations and maintenance, which is entirely a non- federal cost. ES-7. Project Prioritization and Phasing The City of Mountain View will need to consider project priorities for phased implementation. The following factors, summarized in Table ES - 5, are provided for use in prioritization:  Project Cost.  Risk of Flooding. Projects that address higher vulnerability areas will be prioritized more highly.  Potential Damages . Flood damages avoided will be considered in setting project priorities.  Integration with Scheduled Improvements. Implementing Mountain View Shoreline SLR Study CIP projects with other improvements avoids the costs of re-working scheduled improvements at the time the CIP project is implemented.  Likely to Require Wetland Mitigation . Because many of these projects are sited in or adjacent to jurisdictional wetlands or waters of the U.S ., they are likely to require wetland mitigation. Projects that are likely to require wetland habita t mitigation will require additional lead time and coordination, and may be coordinated with th e SBSP Restoration Project for mitigation.  Consistency with SBSP Restoration Project . Projects that are related to the SBSP Restoration Project may need to be implemented prior to r estoration, and perhaps modified, or may not be needed. For the proposed projects, many rank high for ri sk of flooding, since they address existing flood vulnerabilities that only worsen with SLR. Similarly, many of the proposed projects address vulnerabilities with high potential damages, as mo st are designed to protect densely developed commercial areas. An estimated CIP implementation timeline is presented in Table ES - 6, with associated costs shown in five-year increments. Projects that integrate with ot her regional efforts are timed to correspond with those efforts. Projects that address an existing flood risk ar e assumed to be implemented in the first five-year interval. Projects that address flood risk under the low SLR and high SLR scenarios are assumed to be implemented by 2037 and 2067, respectively. Note that, while the projected costs of the low SLR and low SLR+ scenarios are less than for the high SLR scenar io, these are planning scenarios only. Should actual SLR be greater than that used in the low SLR scenar io, additional improvements and costs (not shown in Table ES - 6) will be required to meet flood protection criteria. Since the CIP projects are developed to only a conceptual level of design in this study, initiation of any of these projects will require additional data collection and engineering analysis to inform subsequent design. Depending on the project, data collection may include topographic surveys, property line determinations, levee ownership determinations, right-of-way re view, basemap development, and geotechnical borings. These data would inform additi onal engineering analysis, such as the geotechnical stability of existing levees, settlement of placed fill, and hydraulic performance. A sensitivity analysis could be conducted to evaluate the potential impacts if climate change alters storm runoff intensity and frequency. Using the data and engineering analyses, the project designs can be refined and the cost City of Mountain View City of Mountain View Shoreline Regional Park Community ES 10 ESA / Project No. D120470 Sea Level Rise Study December 18, 2012 estimates updated. The proposed storm drain projects would also benefit from a storm drain planning study to evaluate the potential for consolidating and improving existing storm drain infrastructure throughout the Shoreline Community and considers th e effects sea level rise on groundwater seepage. For the feasibility-level analysis conducted for this st udy, it is premature to identify a permitting strategy. The most efficient permitting process, particularly for CEQA, and as if needed, NEPA, will depend on revised project descriptions, partners, and timing. Re vised project descriptions will indicate which permits are needed and the extent of mitigation, if any, associated with each project. Coordination with potential partners, such as the South Bay Salt Pond Restoration Project and the USACE Shoreline Study, may enable projects to be self-mitigating and other entities to serve as lead permit applicants. Project timing, both of partner projects and City-only projects, can in form the decision to employ either project-based or programmatic permitting. While advancing on its own projects, the City should continue to coordinate with other agencies working in the area, including FEMA (updating the Santa Clara County flood maps), SCVWD (conducting designs for the Palo Alto Flood Basin and lower Perm anente Creek), USFWS (restoration of the former salt ponds), and the USACE (flood assessments for the SSFB Shoreline Study). Many of these adjacent efforts are expected to occur in the coming decade, as well as updates to sea level rise projections. In light of these developments, it is recommended that the Ci ty conduct another sea level rise assessment similar to the current study in another decade. City of Mountain View City of Mountain View Shoreline Regional Park Community ES 11 ESA / Project No. D120470 Sea Level Rise Study December 18, 2012 TABLE ES - 1 VULNERABILITY OF FLOOD MANAGEMENT ELEMENTS Flood Management Element Vulnerable to 1% Flood? Baseline Conditions Low SLR (8”) High SLR (31”) Coastal Flood Defense West Side City Boundary (Palo Alto Flood Basin & Adobe Creek) Yes Yes Yes Coast Casey North Levee Yes Yes Yes High Ground Along North Side of Landfill 1 No Yes Yes Lower Permanente Creek  East bank at Amphitheatre Parkway Pump Station  West Levee at High Level Ditch (WB5)2  Sailing Lake Levee  Lower Permanente Creek (WB1-WB4, WB6, WB7, EB1-EB4) 3  All other areas No Yes No Yes No Yes Yes Yes Yes No Yes Yes Yes Yes No High Ground North of Golf Course Facilities Yes Yes Yes Lower Stevens Creek  Upstream (south) of Crittenden Lane  Crittenden Lane to East Landfill No Yes No Yes No Yes Stormwater Pump Station Hydraulic Capacity 4 Coast Casey Pump Station No No Yes High Level Ditch Pump Station No No No Amphitheatre Parkway Pump Station No No No Crittenden Pump Station No No No Charleston Pump Station No No No Stormwater Gravity Outfalls Plymouth Street Outfall No No No Golf Course Pump Station Outfall 5 No No Yes Sailing Lake Outfall No No Yes Boathouse Parking Lot Outfall No No Yes Michael’s Parking Lot #3 and #4 Outfalls No No Yes Michael’s Parking Lot #1 and #2 Outfalls Yes Yes Yes La Avenida Outfall No No No 1 Vulnerable to erosion, not overtopping. Eros ion threatens integrity of waste containment. 2 Locations of WB1-7 and EB1-4 are shown in Figure ES - 8. 3 Not all reaches are vulnerable for baseline conditions, see Figure ES - 3. 4 Pump stations were evaluated for vulnerability due to in sufficient hydraulic capacity for baseline and SLR conditions; However, pump stations may also be vulnerable to direct flooding. See text for discussion. 5 This item is included with the gravity outfalls rather than pumps because the pump discharges to a vault that drains through an open pipe to the creek. City of Mountain View City of Mountain View Shoreline Regional Park Community ES 12 ESA / Project No. D120470 Sea Level Rise Study December 18, 2012 TABLE ES - 2 VULNERABILITY OF SHORELINE RECRE ATIONAL FACILITIES AND HABITAT MITIGATION SITES Shoreline Element Function Description of SLR Vulnerability Sailing Lake Intake Pump Station Water supply for recreational Sailing Lake Vulnerable to direct flooding in the event of levee failure on Inner Charleston Slough. At risk of such a breach for low and high SLR scenarios. Inner Charleston Slough Habitat mitigation site Site ma y not drain as well, resulting in increased depth, duration and frequency of ponding and conversion of vegetated areas to open water. Damped tidal exchange (through culverts) limits delivery of estuarine sediments and ability of the marshplain to rise with sea level. Tide gates require sufficient operational range to avoid in creasing tidal water levels inside the site (adjacent to the PAFB) and to provide sufficient drainage with SLR. Mountain View Tidal Marsh Habitat mi tigation site Site receives full ti dal inundation, maximizing resiliency with SLR. SLR may increase the depth, duration and frequency of tidal inundation, similar to SLR effects on the natural marshes of the South Bay. Stevens Creek Marsh Habitat miti gation site SLR may increase the depth, duration and frequency of tidal inundation to a greater extent than for the Mountain View Tidal Marsh and natural marshes of the South Bay. As at Inner Charleston Slough, damped tidal exchange through culverts increases vulnerability to SLR. City of Mountain View City of Mountain View Shoreline Regional Park Community ES 13 ESA / Project No. D120470 Sea Level Rise Study December 18, 2012 TABLE ES - 3 CIP PROJECT COST ESTIMATE SUMMARY Project Cost by Scenario Low SLR (8”) Low SLR plus (8”+) High SL R (31”) 1. Charleston Slough and Palo Alto Flood Basin Levee Improvement $13,077,000 $15,532,000 $16,047,000 2. Coast Casey North Levee Improvement $3,066,000 $3,541,000 $3,658,000 3. North Landfill Erosion Protection $9,607,000 $9,607,000 $10,844,000 4. Lower Permanente Creek Levee and Floodwall Improvements $5,525,000 $5,525,000 $9,920,000 5. Golf Course Facilities High Ground Augmentation $3,626,000 $3,626,000 $4,020,000 6. Lower Stevens Creek Levee Improvements $1,474,000 $1,485,000 $1,714,000 7. Coast Casey Pump Station Improvement $2,316,000 $2,316,000 $2,663,000 8. Lower Permanente Creek Storm Drain Improvements (with new pumps) $2,608,000 $2,608,000 $6,598,000 9. Sailing Lake Access Road Improvement $170,100 $170,100 $170,100 10. Sailing Lake Intake Pump Station Modification 1 $692,000 $692,000 $692,000 11. Charleston Slough Tide Gates Improvement $63,900 $63,900 $134,200 SLR Assessment $500,000 $500,000 $500,000 TOTAL $42,730,000 $45,670,000 $56,960,000 Note: All values are in 2012 dollars. 1 Assumes the low cost option of only moving the pump (but not the intake) can be select ed because this is not a function of SLR scenario. The higher cost alternative of also re-lo cating the intake is included in Table ES - 4. City of Mountain View City of Mountain View Shoreline Regional Park Community ES 14 ESA / Project No. D120470 Sea Level Rise Study December 18, 2012 TABLE ES - 4 PROJECT COST ESTIMATE SUMMAR Y WITH THE SBSP R ESTORATION PROJECT Project All SLR scenarios Opportunity for Cost Share Notes 1. Charleston Slough and Palo Alto Flood Basin Levee Improvement $13,077,000-$16,047,000* Yes Rock slope protection would be replaced with upland transition zone. Assumed the same cost for this estimate, though may be lower. 2. Coast Casey North Levee Improvement $3,066,000 - $3,658,000* Yes Rock slope protection would be replaced with upland transition zone. Assumed the same cost for this estimate, though may be lower. 3. North Landfill Erosion Protection $9,607,000 - $10,844,000* Yes Rock slope protection would be replaced with upland transition zone. Assumed the same cost for this estimate, though may be lower. 4. Lower Permanente Creek Levee and Floodwall Improvements $5,525,000 - $9,920,000* No Independent of SBSP Restoration Project. 5. Golf Course Facilities High Ground Augmentation $3,626,000 - $4,020,000* No Independent of SBSP Restoration Project. 6. Lower Stevens Creek Levee Improvements $1,474,000 - $1,714,000* No Independent of SBSP Restoration Project. 7. Coast Casey Pump Station Improvement $2,316,000 - $2,663,000* No Independent of SBSP Restoration Project. 8. Lower Permanente Creek Storm Drain Improvements (with new pumps) $2,608,000 - $6,598,000 * No Independent of SBSP Restoration Project. 9. Sailing Lake Access Road Improvement $170,100 - $170,100* Yes Identical with SBSP Restoration Project. 10. Sailing Lake Intake Pump Station Modification $1,208,000 Yes Assume move pump station and intake with SBSP Restoration Project. Actual cost may be lower. 11. Charleston Slough Tide Gates Improvement $0 NA This project is not needed with SBSP. SLR Assessment $500,000* NA This project would assess City needs in light of SBSP Restoration Project design and other agencies’ efforts. Total subject to cost-share with SBSP Restoration Project $27,128,000 - $31,927,000 Total independent of SBSP $16,049,000 - $25,415,000 TOTAL $43,177,000 - $57,342,000 * No change from CIP cost estimate without SBSP Restoration Project. Note: All values are in 2012 dollars. City of Mountain View Ci t y o f M o u n t a i n V i e w S h o r e l i n e R e g i o n a l P a r k C o m m u n i t y ES 1 5 ESA / Project No. D120470 Se a L e v e l R i s e S t u d y November 2012 TA B L E E S - 5 C I P P R O J E C T P R I O R I T I Z A T I O N A N D I M P L E M E N T A T I O N C O N S I D E R A T I O N S PR O J E C T Co s t R a n g e (L o w - H i g h S L R ) SL R a t w h i c h pr o j e c t i s ne e d e d Po t e n t i a l Da m a g e In t e g r a t e w i t h Sc h e d u l e d Im p r o v e m e n t s Li k e l y t o Re q u i r e We t l a n d Mi t i g a t i o n 1 Relation to SBSP 2 1. C h a r l e s t o n S l o u g h a n d P a l o Al t o F l o o d B a s i n L e v e e Im p r o v e m e n t $1 3 , 0 7 7 , 0 0 0 - $1 6 , 0 4 7 , 0 0 0 Ex i s t i n g Co m m e r c i a l de v e l o p m e n t NA Y e s Required, may be modified 2. C o a s t C a s e y N o r t h L e v e e Im p r o v e m e n t $3 , 0 6 6 , 0 0 0 - $ 3 , 6 5 8 , 0 0 0 E x i s t i n g Co m m e r c i a l de v e l o p m e n t NA Y e s M o d i f i e d 3. N o r t h L a n d f i l l E r o s i o n Pr o t e c t i o n $9 , 6 0 7 , 0 0 0 - $1 0 , 8 4 4 , 0 0 0 Lo w S L R L a n d f i l l e r o s i o n N A M a y b e M o d i f i e d 4. L o w e r P e r m a n e n t e C r e e k Le v e e a n d F l o o d w a l l Im p r o v e m e n t s $5 , 5 2 5 , 0 0 0 - $ 9 , 9 2 0 , 0 0 0 Ex i s t i n g , l o w SL R 3 Co m m e r c i a l de v e l o p m e n t Po t e n t i a l t o i n t e g r a t e w i t h Pe r m a n e n t e C r e e k F l o o d Pr o t e c t i o n P r o j e c t Ye s I n d e p e n d e n t 5. G o l f C o u r s e F a c i l i t i e s H i g h Gr o u n d A u g m e n t a t i o n $3 , 6 2 6 , 0 0 0 - $ 4 , 0 2 0 , 0 0 0 E x i s t i n g Co m m e r c i a l de v e l o p m e n t NA N o I n d e p e n d e n t 6. L o w e r S t e v e n s C r e e k L e v e e Im p r o v e m e n t $1 , 4 7 4 , 0 0 0 - $ 1 , 7 1 4 , 0 0 0 E x i s t i n g Co m m e r c i a l de v e l o p m e n t NA Y e s I n d e p e n d e n t 7. C o a s t C a s e y P u m p S t a t i o n Im p r o v e m e n t $2 , 3 1 6 , 0 0 0 - $ 2 , 6 6 3 , 0 0 0 H i g h S L R Co m m e r c i a l de v e l o p m e n t 20 2 0 s c h e d u l e d im p r o v e m e n t s No I n d e p e n d e n t 8. L o w e r P e r m a n e n t e C r e e k St o r m I m p r o v e m e n t s ( w i t h n e w pu m p s ) $2 , 6 0 8 , 0 0 0 - $6 , 5 9 8 , 0 0 0 Ex i s t i n g , Hi g h S L R 4 Re c r e a t i o n a l fa c i l i t i e s a n d in f r a s t r u c t u r e NA N o I n d e p e n d e n t 9. S a i l i n g L a k e A c c e s s R o a d Im p r o v e m e n t $1 7 0 , 1 0 0 - $ 1 7 0 , 1 0 0 E x i s t i n g Ne e d e d t o im p l e m e n t o t h e r CI P p r o j e c t s NA Y e s R e q u i r e d 10 . S a i l i n g L a k e I n t a k e P u m p St a t i o n M o d i f i c a t i o n $6 9 2 , 0 0 0 - $ 6 9 2 , 0 0 0 L o w S L R Re c r e a t i o n a l fa c i l i t i e s NA N o M o d i f i e d 11 . C h a r l e s t o n S l o u g h T i d e G a t e s Im p r o v e m e n t $6 3 , 9 0 0 - $ 1 3 4 , 2 0 0 E x i s t i n g M i t i g a t i o n si t e N A Y e s I n c o n s i s t e n t NA S L R A s s e s s m e n t $ 5 0 0 , 0 0 0 - $ 5 0 0 , 0 0 0 N A Sh o r e l i n e Co m m u n i t y In t e g r a t i o n w i t h e v o l v i n g pr o j e c t s a n d u p d a t e d S L R pr o j e c t i o n s No I n t e g r a t i o n p l a n n i n g 1 N o n - w e t l a n d h a b i t a t s m a y r e q u i r e m i t i g a t i o n ; t h e r e i s bu r r o w i n g o w l h a b i t a t i n t h e v i c i n i t y o f t h e l a n d f i l l . 2 R e q u i r e d = n e e d e d f o r i m p l e m e n t a t i o n o f S B S P R e s t o r a t i o n P r oj e c t ; M o d i f i e d = w o u l d i m p l e m e n t d i f f e r e n t l y w i t h S B S P . 3 V a r i e s b y p r o j e c t . 4 Va r i e s b y p r o j e c t . M i c h a e l ’ s P a r k i n g L o t # 1 & # 2 O u t f a l l s a r e a t r i s k f o r e x i s t i n g s e a l e v e l . T h e r e m a i n i n g a r e a s a r e a t r i s k f or h i g h S L R . Pr o j e c t L o w  SL R L o w  SL R + H i g h  SL R 2 0 1 3 ‐20 1 7 2 0 1 8 ‐20 2 2 2 0 2 3 ‐20 2 7 2 0 2 8 ‐20 3 2 2 0 3 3 ‐20 3 7 2 0 3 8 ‐20 4 2 2 0 4 3 ‐20 4 7 2 0 4 8 ‐20 5 2 2 0 5 3 ‐20572058 ‐20622063 ‐2067 1. Ch a r l e s t o n  Sl o u g h  an d  PA F B  Le v e e   Im p r o v e m e n t $1 3 , 0 7 7 , 0 0 0   $1 5 , 5 3 2 , 0 0 0   $1 6 , 0 4 7 , 0 0 0   10 ‐15 2 0 % 4 0 % 4 0 % Coordinate  with  SBSP  & SCVWD  regional  effort 2. C o a s t  Ca s e y  No r t h  Le v e e e  Im p r o v e m e n t $ 3 , 0 6 6 , 0 0 0   $3 , 5 4 1 , 0 0 0   $3 , 6 5 8 , 0 0 0   5 ‐10 2 5 % 7 5 % Coordinate  with  SBSP  Restoration  Project 3. N o r t h  La n d f i l l  Er o s i o n  Pr o t e c t i o n $ 9 , 6 0 7 , 0 0 0   $9 , 6 0 7 , 0 0 0   $1 0 , 8 4 4 , 0 0 0   5 ‐10 2 5 % 7 5 % Coordinate  with  SBSP  Restoration  Project 4. Pe r m a n e n t e  Cr e e k  Le v e e  an d  Fl o o d w a l l   Im p r o v e m e n t s $5 , 5 2 5 , 0 0 0   $5 , 5 2 5 , 0 0 0   $9 , 9 2 0 , 0 0 0   5 ‐10 2 5 % 5 0 % 2 5 % First  phase  are  modifications  to  existing  SCVWD  project; remainder  implemented  prior  to  8" SLR 5. Go l f  Co u r s e  Fa c i l i t i e s  Hi g h  Gr o u n d   Au g m e n t a t i o n $3 , 6 2 6 , 0 0 0   $3 , 6 2 6 , 0 0 0   $4 , 0 2 0 , 0 0 0   2 ‐5 1 0 0 % I m p l e m e n t e d  prior  to  8" SLR 6. L o w e r  St e v e n s  Cr e e k  Le v e e  Im p r o v e m e n t s $ 1 , 4 7 4 , 0 0 0   $1 , 4 8 5 , 0 0 0   $1 , 7 1 4 , 0 0 0   2 ‐5 1 0 0 % Existing  risk, no  dependence  on  other  projects. 7. C o a s t  Ca s e y  Pu m p  St a t i o n  Im p r o v e m e n t $ 2 , 3 1 6 , 0 0 0   $2 , 3 1 6 , 0 0 0   $2 , 6 6 3 , 0 0 0   2 1 0 0 % Anticipated  pump  replacement  life  cycle 8. Lo w e r  Pe r m a n t e n t e  Cr e e k  St o r m  Dr a i n   Im p r o v e m e n t s   $2 , 6 0 8 , 0 0 0   $2 , 6 0 8 , 0 0 0   $6 , 5 9 8 , 0 0 0   2 ‐5 4 0 % 60%Michael’s  Parking  Lot  #1  & #2  Outfalls  implemented  early, to  address  existing  risk. Remainder  of  improvements  implemented  prior  to  31” SLR 9. S a i l i n g  La k e  Ac c e s s  Ro a d  Im p r o v e m e n t $ 1 7 0 , 1 0 0   $1 7 0 , 1 0 0   $1 7 0 , 1 0 0   2 1 0 0 % Existing  seepage  risk  and  in  support  of  SBSP  Restoration  Project. 10 . S a i l i n g  La k e  In t a k e  Pu m p  St a t i o n  Mo d i f i c a t i o n $ 6 9 2 , 0 0 0   $6 9 2 , 0 0 0   $6 9 2 , 0 0 0   2 1 0 0 % Coordinate  with  SBSP  Restoration  Project 11 . C h a r l e s t o n  Sl o u g h  Ti d e  Ga t e s  Im p r o v e m e n t $ 6 3 , 9 0 0   $6 3 , 9 0 0   $1 3 4 , 2 0 0   1 1 0 0 % I m p l e m e n t e d  prior  to  8" SLR ‐ SL R  As s e s s m e n t $ 5 0 0 , 0 0 0   $5 0 0 , 0 0 0   $5 0 0 , 0 0 0   1 1 0 0 % Implemented  after  10  years. Co s t  by  ye a r ,  do l l a r s  in f l a t e d  to  ti m e  of  im p l e m e n t a t i o n  ($ M ) : 20 1 3 ‐20 1 7 2 0 1 8 ‐20 2 2 2 0 2 3 ‐20 2 7 2 0 2 8 ‐20 3 2 2 0 3 3 ‐20 3 7 2 0 3 8 ‐20 4 2 2 0 4 3 ‐20 4 7 2 0 4 8 ‐20 5 2 2 0 5 3 ‐20572058 ‐20622063 ‐2067 Lo w  SL R $ 6 6 . 4 1 0 . 8 $               19 . 8 $               12 . 1 $               4. 9 $                   10 . 5 $               ‐ $                   ‐ $                   ‐ $                   ‐ $          ‐$          8.3 $          In  the  event  that  low  SLR  occurs, implementation  of  some  CIPs  (e.g., 4, 5, 7, 11) could  be  delayed  to  2067. In  the  event  that  high  SLR  occurs, additional  improvements  and  costs  (not  quantified  here) will  be  required  after  2037  to  meet  flood  protection  criteria  . Lo w  SL R + $ 7 0 . 3 1 1 . 5 $               21 . 6 $               13 . 6 $               4. 9 $                   10 . 5 $               ‐ $                   ‐ $                   ‐ $                   ‐ $          ‐$          8.3 $          Same  as  for  Low  SLR  scenario  above, except  that  should  high  SLR  occur, the  cost  of  additional  improvements  required  to  meet  flood  protection  criteria  after  2037  will  be  less. Hi g h  SL R $ 9 6 . 2 1 5 . 2 $               23 . 1 $               14 . 4 $               8. 7 $                   13 . 7 $               ‐ $                   ‐ $                   ‐ $                   ‐ $          ‐$          21.0 $        In  the  event  that  low  SLR  occurs, costs  would  be  lower. Implementation  of  some  CIPs  (e.g., 4, 5, 11) could  be  delayed  to  2067  and  others  (e.g., 7  and  8) would  not  need  to  occur  before  2067.  No t e s : Us e  co n s t r u c t i o n  co s t  in f l a t i o n  ra t e  of  3. 2 % ,  th e  av e r a g e  Sa n  Fr a n c i s c o  EN R  CC I  fr o m  19 9 1 ‐20 1 1 . As s u m e  SB S P  Re s t o r a t i o n  Pr o j e c t    im p l e m e n t a t i o n  be g i n s  in  20 1 8 As s u m e  SB S P  Re s t o r a t i o n  Pr o j e c t    pr o v i d e s  we t l a n d  mi t i g a t i o n  fo r  pr o j e c t s  im p l e m e n t e d  pr i o r  to  or  co n c u r r e n t  wi t h  th e  SB S P  Re s t o r a t i o n  Pr o j e c t . As s u m e  pr o j e c t s  re q u i r e d  fo r  lo w  SL R  (8  in c h e s )  mu s t  be  im p l e m e n t e d  by  20 3 7 . As s u m e  pr o j e c t s  re q u i r e d  fo r  hi g h  SL R  (3 1  in c h e s )  mu s t  be  im p l e m e n t e d  by  20 6 7 . As s u m e s  hi g h  SL R  pr o j e c t i o n  (3 1 " ) .  If  ac t u a l  SL R  ra t e  is  sl o w e r ,  im p l e m e n t a t i o n  fo r  so m e  pr o j e c t s  co u l d  be  de l a y e d . ES ‐16 ESA  / Project  No. D120470 December  13, 2012 TA B L E  ES ‐6  CI P  IM P L E M E N T A T I O N  TI M E L I N E Co s t  in  20 1 2  do l l a r s City  of  Mountain  View Ci t y  of  Mo u n t a i n  Vi e w  Sh o r e l i n e  Re g i o n a l  Pa r k  Co m m u n i t y Se a  Le v e l  Ri s e  St u d y Rationale  for  timing % pr o j e c t  by  Ye a r   Pe r m a n e n t e  Cr e e k  Le v e e  an d  Fl o o d w a l l  Im p r o v e m e n t s  in c l u d e s  mu l t i p l e  pr o j e c t s .  As s u m e  pr o j e c t s  im p l e m e n t e d  wi t h  th e  on g o i n g  SC V W D  pr o j e c t  oc c u r  in  Ye a r s  0 ‐5,  th e  re s t  ar e  pr i o r  to  lo w  SL R  da t e .  As s u m e  no  de l a y  ne e d e d  to  accommodate  migitation   re q u i r e m e n t s  fo r  th e  la t e r  pr o j e c t s . Es t i m a t e d  Du r a t i o n   (y e a r s ) To t a l  Co s t ,  In f l a t e d   Do l l a r s  ($ M ) Pl a n n i n g  sc e n a r i o Notes ;) ;) ;) ;) ;););) "! "! "!"! "!"! "! Palo Alto Flood Basin Charleston Slough Pond A1 (former salt pond) Pond A2W (former salt pond) Mountain View Tidal Marsh P e r m a n e n t e C r e e k Crittenden Pump Station Charleston Pump Station High Level Ditch Pump Station Amphitheatre Pkwy. Pump Station Stevens Creek Tidal Marsh A d o b e C r e e k M a t a d e r o C r e e k St e v e n s C r e e k Moffet Field Sailing Lake H i g h w a y 1 0 1 Charleston Detention Pond C r i t t e n d e n L a n e D r a i n a g e C h a n n e l ( " M i t i g a t i o n C h a n n e l " ) Coast Casey Pump Station Sailing Lake Gravity Outfall Sailing Lake Intake Sailing Lake Access Road A d o b e C r e e k Landfill West Landfill East Boathouse Park Lot Gravity Outfall GC1 GC2 GC3 GC4 Golf Course Pump Station A m p h i t h e a t r e P k w y . S a n A n t o n i o R o a d Charleston Slough Tide Gate (off map) Coast Casey Detention Basin Golf Course Facilities C h a r l e s t o n R o a d S h o r e l i n e B l v d . H i g h L e v e l D i t c h 0 1,000 2,000 500 Feet ± ESA PWA Ref # - D120470 City of Mountain View Sea Level Rise Study Project Area - Existing Flood Management Elements J:\D120470.00_CityOfMountainViewShorelineSLR\figures\project_area.mxd Figure ES-1 Source: FEMA Flood Zones, SCVWD Stormwater infrastructure FEMA Certified Levee Existing Levees, not FEMA certified Existing High Ground Existing and Proposed Floodwalls CityLimits Creek Drainage Channel Storm Drain System "!Pump Station ;)Gravity Outfalls Palo Alto Flood Basin Charleston Slough Pond A1 (former salt pond) Pond A2W (former salt pond) Mountain View Tidal Marsh P e r m a n e n t e C r e e k Crittenden Pump Station Charleston Pump Station High Level Ditch Pump Station Amphitheatre Pkwy. Pump Station Stevens Creek Tidal Marsh A d o b e C r e e k M a t a d e r o C r e e k St e v e n s C r e e k Moffet Field Sailing Lake H i g h w a y 1 0 1 Charleston Detention Pond C r i t t e n d e n L a n e D r a i n a g e C h a n n e l Coast Casey Pump Station Sailing Lake Gravity Outfall Sailing Lake Intake Sailing Lake Access Road A d o b e C r e e k Landfill West Landfill East Boathouse Park Lot Gravity Outfall GC1 GC2 GC3 GC4 Golf Course Pump Station A m p h i t h e a t r e P k w y . S a n A n t o n i o R o a d Charleston Slough Tide Gate (off map) Golf Course Facilities Coast Casey Detention Basin C h a r l e s t o n R o a d H i g h L e v e l D i t c h S h o r e l i n e B l v d . 0 1,000 2,000 500 Feet ± ESA PWA Ref # - D120470 City of Mountain View Sea Level Rise Study FEMA Special Flood Hazard Areas J:\D120470.00_CityOfMountainViewShorelineSLR\Maps\figures\Figure 2 FEMA Special FloodHazard Area.mxd Figure ES-2 Source: FEMA Flood Zones, SCVWD Stormwater infrastructure,CA Coastal Conservancy Orthoimagery FEMA Special Flood Hazard Areas [See FEMA(2005) for zone definitions] A Zone AE Zone AO Zone FEMA Certified Levee Existing Levees, not FEMA certified Existing High Ground Existing and Proposed Floodwalls CityLimits Creek Drainage Channel Storm Drain System "!Pump Station "<Gravity Outfalls Note: Flood elevations based on 1% SWL "! "! "!"! "!"! "! "! Palo Alto Flood Basin Charleston Slough Pond A1 (former salt pond)Pond A2W (former salt pond) Mountain View Tidal Marsh P e r m a n e n t e C r e e k Crittenden Pump Station Charleston Pump Station High Level Ditch Pump Station Amphitheatre Pkwy. Pump Station Stevens Creek Tidal Marsh A d o b e C r e e k M a t a d e r o C r e e k St e v e n s C r e e k Moffet Field Sailing Lake H i g h w a y 1 0 1 Charleston Detention Pond C r i t t e n d e n L a n e D r a i n a g e C h a n n e l Sailing Lake Gravity Outfall Sailing Lake Intake A d o b e C r e e k Landfill West Landfill East Boathouse Park Lot Gravity Outfall GC1 GC2 GC3 GC4 Golf Course Pump Station A m p h i t h e a t r e P k w y . Charleston Slough Tide Gate (off map) Sailing Lake Levee S a n A n t o n i o R o a d Coast Casey Pump Station Sailing Lake Access Road Coast Casey Detention Basin Golf Coarse Facilities C h a r l e s t o n R o a d H i g h L e v e l D i t c h S h o r e l i n e B l v d . 0 1,000 2,000 500 Feet ± ESA PWA Ref # - D120470 City of Mountain View Sea Level Rise Study Project Area Vulnerabilities J:\D120470.00_CityOfMountainViewShorelineSLR\figures\Vulnerability of Flood Management.mxd Figure ES-3 Source: FEMA Flood Zones, SCVWD Stormwater infrastructure,CA Coastal Conservancy Orthoimagery Vulnerability Vulnerable for Baseline, Low & High SLR Vulnerable for Low and High SLR Not Vulnerable for Low or High SLR "!Pumps Vulnerable for High SLR "!Pump Not Vulnerable for low/high SLR Outfalls Vulnerable for Baseline, Low & High SLR Outfalls Vulnerable for high SLR Creek Drainage Channel Note: Based on 1% flood event Palo Alto Flood Basin Charleston Slough Pond A1 (former salt pond) Pond A2W (former salt pond) Mountain View Tidal Marsh P e r m a n e n t e C r e e k Crittenden Pump Station Charleston Pump Station High Level Ditch Pump Station Amphitheatre Pkwy. Pump Station Stevens Creek Tidal Marsh A d o b e C r e e k M a t a d e r o C r e e k St e v e n s C r e e k Sailing Lake H i g h w a y 1 0 1 Charleston Detention Pond C r i t t e n d e n L a n e D r a i n a g e C h a n n e l Sailing Lake Intake A d o b e C r e e k Landfill West Landfill East Golf Course Pump Station A m p h i t h e a t r e P k w y . S a n A n t o n i o R o a d Charleston Slough Tide Gate (off map) Coast Casey Pump Station Sailing Lake Access Road Coast Casey Detention Basin Golf Course Facilities C h a r l e s t o n R o a d H i g h L e v e l D i t c h S h o r e l i n e B l v d . 0 1,000 2,000 500 Feet ± ESA PWA Ref # - D120470 City of Mountain View Sea Level Rise Study SLR Inundation Map (Without Project) J:\D120470.00_CityOfMountainViewShorelineSLR\figures\project_area.mxd Figure ES-4 Source: FEMA Flood Zones, SCVWD Stormwater infrastructure FEMA Special Flood Hazard Area High SLR (31") inundation zone (13.2 ft NAVD) Low SLR (8") inundation zone (11.3 ft NAVD) Study Area Note: Flood elevations based on 1% SWL "! "! "!"! "!"! "! 4 4 4 4 ! ! Palo Alto Flood Basin Charleston Slough Pond A1 (former salt pond) Pond A2W (former salt pond) Mountain View Tidal Marsh P e r m a n e n t e C r e e k Crittenden Pump Station Charleston Pump Station High Level Ditch Pump Station Amphitheatre Pkwy Pump Station Stevens Creek Tidal Marsh A d o b e C r e e k M a t a d e r o C r e e k St e v e n s C r e e k Moffet Field Sailing Lake H i g h w a y 1 0 1 Charleston Detention Pond C r i t t e n d e n L a n e D r a i n a g e C h a n n e l Sailing Lake Gravity Outfall Sailing Lake Intake A d o b e C r e e k Landfill West Landfill East Boathouse Park Lot Gravity Outfall GC1 GC2 GC3 GC4 Golf Course Pump Station A m p h i t h e a t r e P k w y . 6 6 6 6 Project 5. Golf Course Facilities High Ground Augmentation See Figure ES-9 for detail Project 6. Lower Stevens Creek Levee Improvement Project See Fig ES-10 for detail 6 Projects 4 and 8 Lower Permanente Creek, Sailing Lake Outfall, and Parking Lot Storm Drain Outfalls.See Figure ES-8 for details Project 1. Charleston Slough West Levee S a n A n t o n i o R o a d Projects: 1,2,7,9 and 10 Charleston Slough, Palo Alto Flood Basin,and Coast Casey Area See Figure ES-7 for detail Project 11. Charleston Slough Tide Gate (off map) 4 4 Project 3.Landfill Erosion Protection Coast Casey Pump Station Sailing Lake Access Road Coast Casey Detention Basin Golf Course Facilities C h a r l e s t o n R o a d H i g h L e v e l D i t c h S h o r e l i n e B l v d . 0 1,000 2,000 500 Feet ± ESA PWA Ref # - D120470 City of Mountain View Sea Level Rise Study Proposed CIP Projects J:\D120470.00_CityOfMountainViewShorelineSLR\figures\project_area.mxd Figure ES-5 Source: FEMA Flood Zones, SCVWD Stormwater infrastructure,CA Coastal Conservancy Orthoimagery Baseline Conditions FEMA Certified Levee Existing Levees, not FEMA certified Existing High Ground Existing and Proposed Floodwalls Creek Drainage Channel Sailing Lake Pump Intake "!Pump Station ")Gravity Outfalls Proposed Adaptation Project New Levee Improved Levees Floodwall New or Improved Erosion Protection !!Access Road Improvement Fill_Areas 4 Pump Station new or improved New Roads Palo Alto Flood Basin Charleston Slough Pond A1 (former salt pond) Pond A2W (former salt pond) Mountain View Tidal Marsh P e r m a n e n t e C r e e k Crittenden Pump Station Charleston Pump Station High Level Ditch Pump Station Amphitheatre Pkwy. Pump Station Stevens Creek Tidal Marsh A d o b e C r e e k M a t a d e r o C r e e k St e v e n s C r e e k Sailing Lake H i g h w a y 1 0 1 Charleston Detention Pond C r i t t e n d e n L a n e D r a i n a g e C h a n n e l Sailing Lake Intake A d o b e C r e e k Landfill West Landfill East Golf Course Pump Station A m p h i t h e a t r e P k w y . S a n A n t o n i o R o a d Charleston Slough Tide Gate (off map) Coast Casey Pump Station Sailing Lake Access Road Coast Casey Detention Basin Golf Course Facilities C h a r l e s t o n R o a d H i g h L e v e l D i t c h S h o r e l i n e B l v d . 0 1,000 2,000 500 Feet ± ESA PWA Ref # - D120470 City of Mountain View Sea Level Rise Study SLR Inundation Map (With Project) J:\D120470.00_CityOfMountainViewShorelineSLR\figures\project_area.mxd Figure ES-6 Source: FEMA Flood Zones, SCVWD Stormwater infrastructure FEMA Special Flood Hazard Area High SLR (31") inundation zone (13.2 ft NAVD) Study Area Note: Inundation Mapping assumes implementation of CIP project(s) to provide flood protection within the city of Palo Alto. Without such a project(s), a large protion of the southwestern part of the Study Area would be a risk from City of Palo Alto Flooding" "! "! ! ! ! ! ! ! ! ! 4 4 Palo Alto Flood Basin A d o b e C r e e k Coast Casey Pump Station Sailing Lake Intake Pump Station Sailing Lake Access Road Inner Charleston Slough Pond A1 (former salt pond) Sailing Lake Coast Casey Detention Basin 0 250 500 125 Feet ± PWA Ref # - D120470.00 City of Mountain View Sea Level Rise Study Charleston Slough, Palo Alto Flood Basin, and Coast Casey Area Project Detail Figure ES - 7 S:\GIS\D120470.00_CityOfMountainViewShorelineSLR\Maps\figures\Figure 6 Coast Casey and Inner Charleston Slough Baseline Conditions Existing High Ground Sailing Lake Pump Intake Existing Levees, not FEMA certified "!Pump Station Creek CityLimits Proposed Adaptation Project Improved Levee !!Access Road Improvement 4 Pump Station new or improved Source: SCVWD Stormwater Infrastructure, CA Coastal Conservancy Orthoimagery "< "< "< "< "< "< "< "! "! "! 4 4 4 Mountain View Tidal Marsh P e r m a n e n t e C r e e k High Level Ditch Pump Station Amphitheatre Pkwy. Pump Station Sailing Lake Shoreline Detention Pond Coast Cosey Pump Station Retrofit Sailing Lake Gravity Outfall Sailing Lake Intake Sailing Lake Access Road Landfill West Landfill East Golf Coarse Facilities Boathouse Parking Lot Pump Station (new)GC1 # 2 GC3 GC4 Golf Course Pump Station A m p h i t h e a t r e P k w y Sailing Lake Levee WB6 WB5 WB4 WB3 WB2 WB1 EB1 EB2 EB3 EB4 Parking Lot Pump Stations (new) WB7 C h a r l e s t o n R o a d H i g h L e v e l D i t c h S h o r e l i n e B l v d . 0 1,000 2,000 500 Feet ± PWA Ref # - D120470.00 City of Mountain View SLR Study Lower Permanente Creek Project Detail Figure ES - 8 S:\GIS\D120470.00_CityOfMountainViewShorelineSLR\Maps\figures\Figure 5 Lower Permanente Creek Project Detail Baseline Conditions Existing High Ground Existing and Proposed Floodwalls "!Pump Station "<Gravity_Outfalls Creek Drainage Channel Proposed Adaptation Project New Levee Floodwall New or Improved Improved Levee 4 Pump Station new or improved Source: SCVWD Stormwater Infrastructure, CA Coastal Conservancy Orthoimagery Mountain View Tidal Marsh Raise ground for low SLR (8 inch) scenario with room to raise in the future for height SLR scenario Realign road to high ground 0 150 300 75 Feet ± PWA Ref # - D120470.00 City of Mountain View Sea Level Rise Study Golf Course Facilities High Ground Augmentation Project Detail Figure ES - 9 Notes: See figure 5 for Lower Permanente Creek Project Detail, which includes stormwater infrastructure improvments in this area. S:\GIS\D120470.00_CityOfMountainViewShorelineSLR\Maps\figures\Figure_4 Mountain Vied Tidal Marsh Project Detail Proposed Adaptation Project Realign Roads Fill Areas Source: CA Coastal Conservancy Orthoimagery "! Crittenden Pump Station Stevens Creek Tidal Marsh St e v e n s C r e e k Moffet Field C r i t t e n d e n L a n e D r a i n a g e C h a n n e l Landfill East 0 250 500 125 Feet ± PWA Ref # - D120470.00 City of Mountain View Sea Level Rise Study Lower Stevens Creek Levee Improvment Project Detail Figure ES - 10 S:\GIS\D120470.00_CityOfMountainViewShorelineSLR\Maps\figures\Figure 3 Lower Stevens Creek Project Detail Baseline Conditions Existing High Ground FEMA Certified Levee Existing Levees, not FEMA certified Creek Drainage Channel "!Pump Station CityLimits Proposed Adaptation Project New Levee Improved Levee New Maintenance Road Source: SCVWD Stormwater Infrastructure, CA Coastal Conservancy Orthoimagery