Tidal Link

Tidal Link

Disperse Accumulate Connect

Madeline Goldkamp Master of Landscape Architecture Candidate 2017 Department of Landscape Architecture University of Minnesota - Twin Cities

Capstone Committee Karen Lutsky, Assistant Professor UMN John Koepke, Professor UMN Andrew Montgomery, Adjunct Assistant Professor UMN Thank you for all of your support and guidance throughout this capstone project!

Acknowledgments Local Research and Management Contacts Dr. Jeff Crooks, Research Coordinator, Tijuana River National Estuarine Research Reserve Dr. Sarah N Giddings, Assistant Professor UCSD , Scripps Institute of Oceanography Madeleine Harvey, PhD Candidate UCSD, Scripps Institute of Oceanography Dr. Keith Meldahl, Geology and Oceanography Professor, MiraCosta College Dr. Eugene Wahl, NOAA Dr. Kenneth Cole, Adjunct Professor, NAU Family & Friends Thank you to everyone who supported me through this master’s program.

I could not have done this without your love and encouragement!

Thanks to my parents for encouraging me to explore.

2

Contents

3

01

Introduction

115

Conclusion

05

Context

117

Figures

21

History

120

References

31

Climate Change

37

Salt Marsh Dynamics

47

Adaptation Strategy

57

Design 4

Introduction

This is a study of one of the last remaining salt marshes and waterfowl refuges in Southern California. With the pressures of climate change, Los PeĂąasquitos Lagoon will be faced with rising sea levels and increased urbanization in its watershed. How can we create space for coastal retreat and transition our relationship with the changing coastline?

5

1

Introduction This is a study of one of the last remaining salt marshes and waterfowl refuges of Southern California. With the pressures of climate change, Los Peñasquitos marsh will be faced with rising sea levels and the pressures of urbanization in its watershed. Sea level could rise as much as six feet or more in the coming century. How can we create space for coastal retreat and transition our relationship with the changing coastline?

Los Peñasquitos Marsh located in the Torrey Pines State Preserve, which is part of a 2,000 acre State Reserve of public beaches, cliffs, and coastal marshland along the Pacific Ocean. It is fed by fresh water from Los Peñasquitos Creek and Carmel Creek, which run east to west through the northern region of San Diego County.

As urbanization has spread throughout the watershed, polluted rainwater and outfalls have increasingly threatened the hydrologic systems of Los Peñasquitos marsh and its tributaries. The development of the beach has also put strain on the ecological functions of the marsh. The tidal inlet where the marsh connects to the ocean is constantly being blocked by sand as it deposits during high tides, because it is constricted by the highway and the train line which bisects it in two.

tons of carbon annually and provide important habitat for many other beneficial species, which are important for tourism, recreation, education, and research (Barbier et al., 2011). Having an understanding for the historical ecology of urban streams and estuaries helps to predict how these vital systems will respond to predicted climate change scenarios so that resilient adaptation strategies can be developed.

6,800 ha Coastal Marsh Remaining in Southern California - a decrease of 75%–91% of historic extent

“Current estimates suggest that in 2100, the sea could rise by six feet (NOAA)...”

-The San Diego Union-Tribune

Anthropogenic forces have brought the beach and marshland to their current conditions.

Going forward with an understanding that these landscapes will change as the sea rises, adaptive management and planning for climate change will play a key role in how we will inhabit and recreate in these coastal landscapes in the future. There needs to be and understanding of the ecosystem services that these coastal marsh systems provide, which include: protection from storm surge and erosion, natural filtering that purifies rainwater runoff from urban environments, they serve to maintain fisheries because they shelter juvenile animals, they sequester millions of

1

2

Context

3

4

Context Urban Pressures In Southern California, coastal salt marsh habitat is estimated to be about 6800 ha, a decrease of 75%–91% of its historic extent (Ferren 1990, Dahl and Johnson 1991, Wahl 2000). Over the past century, development in the watershed of Los Peñasquitos Lagoon has caused an increase in fresh water runoff during nonstorm dry season flows in the summer months. Los Peñasquitos

Creek and Carmel Creek now provide a perennial source of freshwater to the lagoon.

One study looking at the relationship between urban development and changing vegetation types within Los Peñasquitos Lagoon found that “the amount of urban land use/cover in the watershed is negatively and significantly correlated with the areal extent of salt panne and mudflats, but positively and significantly correlated with the

areal extent of riparian, brackish marsh, and grass vegetation” (Greer & Stow, 2003, p. 493).

This conversion from salt marsh to brackish marsh habitat has changed the vegetation within the lagoon, affecting species reliant on salt marshland. Urbanization in addition to the restriction of tidal flows into the lagoon from train and road development has accelerated this conversion process.

Los Peñasquitos Lagoon Watershed Open Space & Preservation

47% Residential & Commercial

33%

Torrey Pines State Reserve

Industrial / Transportation Pacific Ocean

20%

Los Peñasquitos Watershed 60,000 acres 265,000+ People “We expect to experience hotter and more humid heat waves and less frequent but more intense rainfall.”

- San Diego, 2050 Is Calling

Ocean & Streams

San Diego

Tijuana

Los Peñasquitos Watershed 5

Streams

Roads 6

Los Peñasquitos Watershed

Del Mar

Pacific Ocean

Los Peñasquitos Lagoon Torrey Pines State Reserve

La Jolla Shores

Los Peñasquitos Watershed 7

Streams

Open Space / Preserve/ Recreation

Residential / Commercial

Industrial / Transportation 8

Context Maps

Hydrology

Residential

Torrey Pines State Preserve

Highway & Train

Carmel Valley Rd

Torrey Pines State Beach

Coast Highway 101

Los Peñasquitos Lagoon

56 Freeway

LOSSAN Rail Corridor

Interstate 5

Projected 100 yr Flood Extent [2100] 9

Single Family & Multi Family Housing

Preserve Boundary

Trails

Major Transit Routes

1” = 4000’

10

Landscape Management Los Peñasquitos Lagoon is at risk for eutrophication because of the nutrient rich fresh water entering the lagoon. With the restricted tidal flow, the single opening of the lagoon to the ocean must be continuously managed as sand is deposited by winter storms and longshore currents. The mouth of the lagoon has been dredged since 1968, and without this intervention “an alternating pattern of hypersaline conditions caused by summer evaporation and excessive dilution caused by winter storm events results, depending on the height of the sand barrier

and rainfall conditions” (Mudie and others 1974, Wahl 2000).

An enhancement plan was developed in 1985 by the California Coastal Conservancy to deal with these problems, with partial funding provided by local developers and homeowners’ associations in the watershed. A management program designed by the Los Peñasquitos Lagoon Foundation “ called for the monitoring of channel water quality and the mechanical opening of the mouth before

water quality became poor enough to kill channel organisms” (Crooks & Uyeda, 2010). The lagoon is currently monitored by the Pacific Estuarine Research Laboratory, which is based out of San Diego State University.

on the lagoon and how critical it is to maintain tidal flushing within the lagoon to avoid hypoxia (low oxygen conditions). This research serves as a resource for adaptive management of the lagoon and other regional coastal marsh ecosystems.

Research of lagoon morphodynamics is conducted by the Sarah N. Giddings Laboratory at the UCSD Scripps Institute of Oceanography. Monitoring of extreme tides in relation to sediment movement help us to understand the effects that climate change will have

In addition, outreach conduted by these organizations helps to teach communities about the importance of these vital ecosystems.

Outreach

Monitoring

Torrey Pines State Reserve 2000 acres Los Peñasquitos Lagoon 640 acres

California State Parks

NOAA

US Fish & Wildlife Service

Los Peñasquitos Lagoon Foundation

Tijuana River National Estuarine Research Reserve

Southwest Wetlands Interpretive Association

California Coastal Commission

City of San Diego

Caltrans DOT

Scripps Institute of Oceanography

Wetland Exploration Program & Monitoring - UCSD Scripps Institute of Oceanography | Sarah N. Giddings Laboratory (3) 11

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Critical Habitat Coastal marshlands serve as a nursery for many fish and shark species. There are about 80 species of fish inhabit Southern California bays and estuaries. They also serve as important migratory stops and nesting grounds for many avian bird species.

The tens of thousands of birds that come to coastal marshlands rely on their abundance of marine invertebrates and small fish as a food source. Fish that breed and spawn in the wetlands also consume many of these animals.

The invertebrates that live in the wetlands include mussels, clams, horn snails, worms, crabs and amphipods. An abundance of reptiles and small mammals also live amongst the higher marsh zones.

Many rare and endangered species also rely on coastal marshes like Los PeĂąasquitos lagoon, which are directly affected by hydrologic changes and the loss of habitat that will occur as the sea level rises.

Marsh Habitat Zonation (5)

Mouth of Los PeĂąasquitos Lagoon being re-opened (4) 13

Leopard Shark (6)

Round Stingray (7)

Light Footed Clapper Rail (8)

Western Snowy Plover (9)

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Site Users When you visit Torrey Pines State Preserve, the vastness of the Pacific Ocean draws you out. There is something exciting and beautiful about feeling so vulnerable at the edge of a continent.

People come to explore the beach, swim, surf, collect rocks and shells, bathe in the sunshine, BBQ with friends & family and hike the cliffs to get that perfect view. The space is relaxing with the smell of seaweed, the sound of seagulls, and the cool breeze.

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If you are in search of a more secluded experience away from the crowds of beach goers, then there is a small trail along the edge of the lagoon. This offers vast open views and a quiet place to observe birds and a wide array of native plant species. Torrey Pines and the Los PeĂąaquitos Lagoon are a gem in the middle of the sprawling county of San Diego.

Walking the Beach (10)

Hiking the cliffs (11)

Surfing & Swimming (12)

Grabbing burritos at Roberto’s (13)

Torrey Pines State Beach (14) 16

Community Resistance Coastal salt marshes are vital pieces of green infrastructure that we undervalue. Urbanization has put many pressures on these ecosystems, which are preventing them from adapting to climate change.

“Keep proposed double tracks far away from Peñasquitos Lagoon!”

Coastal communities will be be faced with incredibly difficult circumstances and decisions in the coming century. The Torrey Pines community has voiced their concerns for the lagoon and appreciatetion for the lagoon as they fight plans for potential train infrastructure expansion through the lagoon.

- The Carmel Valley News

Ecosystem Services Climate Change Sea Level Rise Drought Beach Loss

Water Cleansing

Lagoon

Carbon Sequestration Habitat

Urbanization Polluted Water Runoff Decreased Public Space Transit Infrastructure Sediment Alteration

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LOS PEÑASQUITOS LAGOON: Deconstructing the T-sheet Los Peñasquitos Lagoon as shown on the T-sheet, surveyed May to July 1889. (Rodgers and Nelson 1889; courtesy of NOAA)

a

History a The inlet is shown open at the time of the T-sheet survey.

As for San Dieguito lagoon, the location of the Mean Lower Low Water line (dotted, just offshore) indicates that the channels lacing the marsh would have often drained completely at low tide.

b

b The “Beach Shingle R.R.” spur of the California Southern Railroad was constructed in order to transport cobble from the beach and dune complex to pave streets in San Diego (Rodgers 1889).

c d

c A large salt marsh plain is shown as the predominant lagoon feature. No salt flat is depicted, though other early sources – including a survey contemporary with the T-sheet (Unknown 1888a) – do document the historical presence of salt flat. d Numerous roads are shown crisscrossing the marsh, suggesting that the marsh plain was dry enough at certain times of the year to permit passage.

e

e The original California Southern Railroad line ran along the eastern side of the lagoon, much further inland than the coastal route taken across the other North County lagoons.

As a result, in contrast to other systems the railroad berm did not constrict the lagoon mouth or restrict circulation in large portions of the marsh.

N

¼ mile 1:15,000

134 NORTHERN NORTHERN SAN SAN DIEGO DIEGO COUNTY COUNTY LAGOONS LAGOONS

19

~~ 135 135 LOS LOS PENASQUITOS PENASQUITOS LAGOON LAGOON

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History A Record of Time After the most recent glacial period, “rapid postglacial rise in sea level then inundated the Los Peñasquitos Lagoon forming a bay with rocky, cobbly beaches before 6000 yr B.P. (Inman, 1983 (as cited in Cole et al., 2000, p. 346)). 2000 years later, sandy beaches began to form as tectonic uplift as well as lagoonal infill caught up with slowing sea level rise.

Soil core samples from the lagoon hold a record of the site and its surrounding conditions in recent history. These samples date back to approximately 3600 years ago (1600 B.C.). Certain plant species can be identified by looking at the pollen present in the layers of the core sample.

In 2600 yr B.P. an increase in cottonwood pollen suggests that there was once more freshwater entering the lagoon, indicating moister climate

“The rapid postglacial rise in sea level then inundated the Los Peñasquitos Lagoon forming a bay with rocky, cobbly beaches before 6000 yr B.P.”

conditions in the region. These climate conditions can be traced moving north over a 1000 year time span. The wetter winter climate was also the beginning of increasing fire frequency in the region. This was due to the abundance of herbaceous material present, and also the aboriginal Kumeyaay people living near the lagoon who likely used fire for landscape management (Christenson, 1990 (as cited in Cole et al., 2000, p.

350). Higher levels of large particles of charcoal

mark the early settlement period of ranchers in the area burning woody brush. The first recorded settlement in the watershed is in 1823 when one league (4243 acres) of land was awarded to Captain Francisco Maria Ruiz, a Commandant of the San Diego residio of Mexico (Peñasquitos. org). Twenty years later the United States invaded California, starting the Mexican-American War in 1846.

Fire used by aboriginal people to burn chaparral First recorded settlement in watershed Mexican-American War Intensive grazing era Mouth of estuary closed by accumulating sediments, road construction (1909), and railroad berm (1925) Bare mud flats of fresh sediment fill estuary Pinus torreyana (endangered) cut for fuel over previous 50 yr Rise in automobile traffic using leaded gasoline (Interstate 5 built nearby) Los Peñasquitos Marsh

1650

1823

1846

1860

1910

1925

1965

Kumeyaay of Southern California (16)

Time 21

End of last ice age

Evidence of Kumeyaay Indians in San Diego

Los Peñasquitos Marsh was a bay

Wet Climate & Many Fires

12,000 BP

10,000 BP

6,000 BP

2,750 BP

?

Present 22

“It forms a natural exhibit that cannot be duplicated in any other portion of the world.

It is a priceless heritage; let us all help to preserve its beauty for generations to come.�

- Torrey Pines State Park Guide Book

23

24

1920s

History European settlement in the area is evident in the soil core as disturbances on the landscape caused erosion of upland sediment. There was a significant rise in sedimentation rates when compared to the end of the Pleistocene, the previous epoch, which ended approximately 11,700 years ago (Cole & Wahl, 2000, p. 346). This resulted in “50 to 55 cm of excess sediment above its presettlement elevation relative to sea level” (Cole et al., 2000, p. 349). Larger sediment loads

decrease the volume of water entering and exiting the lagoon with every tide causing higher sodium content in the water. Later on when a road was constructed over the lagoon in 1909 the estuary was further constricted. In 1925 the railroad was constructed through the site and in 1933 Highway 101 was constructed along the coastline, completely closing off the lagoon to the Pacific Ocean (Hubbs et al., 1991 (as cited in Cole et al., 2000, p. 345)).

Highway 101 in 1920s (18)

1961

1914–1915 Panoramic Automobile Road Map and Tourist Guide Book of Southern California (17) 25

Vintage Highway 101 in 1961 (19) 26

1941

Fishing and Camping on Torrey Pines Beach 1941 (20) 27

28

Climate Change

29

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Climate Change The uncertainties of climate change and sea level rise will have profound effects on our cities in the coming century. California will be faced with longer droughts, higher fire risk, and a growing population.

probability of co-occurring warm–dry conditions like those that have created the acute human and ecosystem impacts associated with the ‘exceptional’ 2012–2014 drought in California” (Diffenbaugh, Swain, & Touma, 2015).

On average San Diego receives 10 inches of rain annually in its coastal regions. Predictions for future trends in rainfall indicate that “anthropogenic warming is increasing the

San Diego depends on outside water sources, including snow melt from the Sierra Nevada Mountain Range and the Colorado River. The past four years California has been faced with

major drought “leading to massive groundwater overdraft, cutbacks to farmers, reductions in hydroelectricity generation, and a range of voluntary and mandatory urban water restrictions” (Mann & Gleick, 2015). Reduced availability of fresh water will force San Diego to rethink how water is used and re-used within its stormwater and wastewater systems.

“Extreme high tides and winter storms magnified by sea level rise will result in more frequent and widespread coastal flooding.” .

Lagoon Inlet During King Tide (21) 31

32

6.6+ ft SLR rise by 2100

As the sea rises, the hydrology of the Los PeĂąasquitos Lagoon will change drastically. As the marsh becomes more brackish, marshland plant communities will begin to migrate inland and the current beaches along the west shore will cease to exist. The cliffs to the south of the lagoon will significantly erode.

The current topography will split the marsh into two regions as it moves into the base of its

tributaries. This can be observed in the predicted sea level rise maps provided by the National Oceanic and Atmospheric Association (NOAA).

Adjacent roads and properties will also be increasingly at risk of flooding, which will force both the city and state park service to reevaluate how they manage this critical piece of green infrastructure.

Current Sea Level Rise Prediction

Storm Surge Mean Higher-High Water Mean Sea Level Mean Lower-Low Water NOAA Sea Level Datums for La Jolla, CA (22)

Scenarios of Sea Level Rise to 2100 - California Climate Change Center (23)

Wetland Intertidal Zones (24) 33

34

Salt Marsh Dynamics

35

36

Vegetation Transition

Plant Communities

Tidal Flow

Marsh Migration

The interface between the lagoon and Torrey Pines beach will need to be adapted to predicted sea level rise. Opening tidal flow through the highway and train will increase tidal flushing and reduce the management demand for the site.

Determine brackish transition zones between fresh water tributaries and the lagoon. These zones will be variable and shift inland over time as they mark the movement of water and vegetation typology. To minimize marsh habitat loss, the adjacent upland areas can be adapted to accommodate for eventual water level rise as they become the new marshland.

Freshwater/brackish wetland Open water/mud flat

Low Marsh Species

Distichlis spicata

Cuscuta salina

Cressa truxillensis

Arthrocnemum subterminale

Monanthochloe littoralis

Jaumea carnosa

Frankenia salina

Salt flat (seasonally flooded) Salt marsh

High Marsh Species

Developed HISTORICAL 1988

500

Sarcocornia pacifica 400

Transition/Upland Species (Brackish Zones)

300 ACRES

CONTEMPORARY

200

100

N

0.5 mile

0

Typha sp.

HISTORICAL

CONTEMPORARY

Polypogon monspeliensis

Lasthenia glabrata

Pterostegia drymarioides

Vegetation transition (Elwany)

37

38

Marsh Vegetation Subtidal Channel

High Marsh

Low Marsh

Mudflat

Upland

Transition Zone

Coyote Brush Baccharis pilularis

Spiny Rush Juncus acutus

Pickleweed Sarcocornia pacifica

39

Alkali Heath Frankenia salina

Salt Grass Distichlis spicata

Sea Lavender Limonium californicum var. mexicanum

California Sagebrush Artemisia californica

Black sage Salvia mellifera

Lemonade Berry Rhus integrifolia

Glasswort Salicornia europaea

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Sediment Movement The mouth of the lagoon is constantly changing as the tides rise and fall two times everyday.

This tidal flushing is critical to the water quality conditions within the lagoon. As excess fresh water flows into the lagoon from urbanized areas, this can cause hypoxia within the lagoon that threatens wildlife. Understanding the morphodynamics of the lagoon is critical to making informed management decisions.

Typical Tide Levels (Current Sea Level) +8 ft +7 ft +6 ft +5 ft +4 ft +3 ft +2 ft +1 ft MLLW -1 ft

The long shore current for this littoral shelf moves sediment south towards La Jolla Shores.

When sediment reaches this point, it collects into a 500 ft underwater canyon. This means that the sediment placed on our beaches will have to be continually replenished at a large cost in order to keep up with sea level rise. Offshore dredging for beach nourishment has negative impacts on the nearshore ecology but also on the shore ecology as large amounts of sediment suffocate

Wave Action

the organisms that live in these areas. A recent study of San Diego beaches showed that 15 months after beach nourishment, beaches had approximately 50% less intertidal invertebrate population that those beaches that did not undergo beach nourishment (Strelich). This reduction affects birds and other animals that feed on these organisms.

Sediment Movement

Inlet

Los PeĂąasquitos Lagoon

La Jolla Canyon

Sediment Accumulation

Los PeĂąasquitos Lagoon

Long Shore Current Long Shore Current

41

0

0.5

1

Miles

42

Historic Coastline & Sea Level Rise Erosion from streams and coastal bluffs nourish our lagoons and beaches. As sea levels rise and fall so does the elevation of the lagoon as seen in the marsh formation figure (Meldahl). Today we have limited these erosion processes through retaining walls and dams, which prevent sediment from nourishing our beaches and lagoons.

diminishing beaches and lagoon inundation across the west coast. Holding the coastline with infrastructure will only last for so long. It is clear that we must looking at past geologic conditions to start understanding how we can preparing and adapting to a future of climate change and sea level rise.

Marsh Formation

6-7 ft Sea Level Rise / Century

With another period of accelerated sea level rise approaching, we are already experiencing

Coastline 6000 years ago

Historic Sea Level Rise & Marsh Formation (38)

Coastal Marsh Formation & Cliff Erosion (38) 43

44

Adaptation Strategy

45

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Sea Level Rise Scenario The sea level rise scenario for this adaptation strategy is based on the projected models published by the California Climate Change Center and NOAA. The worst case scenario for the mean high high water level [MHHW] by the end of the century will be approximately 2 m higher than the current MHHW reaching a level of 16.67 ft NAVD in elevation.

Based on this sea level rise scenario and if no

action is taken, the beach width will completely disappear with 4 ft of sea level rise, which would occur by approximately 2050. Current vegetation typologies will migrate upland with the rise in sea level leaving open water conditions throughout the lagoon. Key adaptation strategies would need to be implemented throughout this time period to minimize risk, maintain public access and provide space for the marsh to migrate upland.

0 ft

1 ft

2 ft

3 ft

4 ft

5 ft

Sea Level Rise

Beach Width

2100 ?

120’

Winter

65’

Summer What Beach?

0’

1. Beach Restoration of Parking Lot 2. Relocate Park Entry 3. Neighborhood Retreat &Trail 4. Train Removal & Marsh Nourishment 5. Road Removal & Dune Restoration

6 ft

Flood Risk (annual)

1%

5%

15 %

50 %

100 %

100 %

100 %

13 12

Lagoon (ft NAVD)

11 10

Upland

Marsh?

9 8 7 6 5 4

Transition Marsh

3

Subtidal

2 1 0

Adaptation Strategy

Dune Restoration

Lagoon Trail Connection

Dune Migration

Beach Lot

Sediment Capture

Marsh Migration

Marsh Nourishment

Marsh Nourishment

Neighborhood Retreat

Marsh/Upland Restoration

Train Realignment

Public Access

Train Removal Coast Highway Removal

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Adaptation Techniques Sediment Dispersal

Constructed Wetlands

Marsh Nourishment

Trail Buffer

Rolling Easement

Constructed Reef

Inland Dune Strengthening

Road Removal

Dune Restoration

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SEDIMENT DISPERSAL Sediment that accumulates at the inlet to the lagoon can be distributed throughout the lagoon and beach for marsh migration of vegetation and for use in dune restoration. This investment in the lagoon will help transition habitat typologies as the sea level rises.

Road Removal

Sediment Dispersal

Constructed Reef

Marsh Nourishment

Trail Buffer

Inland Dune Strengthening

Constructed Wetlands

Rolling Easement

Dune Restoration

CONSTRUCTED WETLANDS Currently, untreated stormwater enters the lagoon directly through storm drain infrastructure. Constructed wetlands above ground serve as an alternative solution to cleaning stormwater prior to entering the lagoon.

MARSH NOURISHMENT As the sea level rises, salt marsh vegetation will migrate upland. Creating open upland spaces is crucial for this process to occur and for preservation of upland habitat areas within the lagoon ecosystem.

TRAIL BUFFER The creation of trails and open space along the edges of the lagoon provide areas for marsh migration and recreational opportunity.

ROLLING EASEMENT Properties and infrastructure in danger of flooding along the edge of the lagoon will be removed when they lie within the Mean High High Water elevation. This coastal retreat is necessary for public safety and for the creation of open upland spaces.

CONSTRUCTED REEF The beach will start to disappear as the sea level rises because their is limited sediment from erosion accumulating on the beach. Nearshore constructed reef structures promote the accumulation of sediment along beaches and may improve wave conditions for surfing.

INLAND DUNE STRENGTHENING Prior to the removal of the coastal highway, sediment can be distributed to the lagoon side of road to restore dune habitat. This accumulation of sediment supports the eventual removal of road and inland migration of beach nearing the end of the century.

ROAD REMOVAL The removal of the coastal highway and other low lying roads will provide space for sea level rise and promote inland migration of the dune beach system, which is necessary for its preservation as a habitat and recreational space.

DUNE RESTORATION Sediment dispersal and establishment of dune vegetation is crucial for the restoration of dune processes. Dune restoration provides habitat for many endangered bird species and a unique experience for visitors.

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Infrastructure Loss & Value The California Department of Boating and Waterways recently conducted a study on Torrey Pines Sate Beach to understand the extent of infrastructure loss and value, as well as the recreational value that will be lost under different sea level rise scenarios. With 2 m of sea level rise there will be extensive infrastructure loss.

1 Low Lying Roads

(2.0 M rise by 2100)

Invaluable

State Reserve Land

Income from park visitors

9M

LOSSAN Railroad

Track at risk

36+ Businesses and Homes

Flood damage

6.7 M

Coastal Highway & Carmel Valley Road

Damaged and unusable roads

5.1 M

PV Spending

Local and state spending

143.3 M

PV Taxes

Local and state tax base

3.7 M

roa d

364.8 M

CA Dept. of Boating & Waterways 51

Los Peñasquitos Lagoon

ail

30 M

NR

Reduced beach access & recreational value

SA

Beach & Public Space

S LO

Water Purification, habitat reduction

way

Salt Marsh Threatened

ach

4 Road Erosion

Aggregate Monetary Loss

Coast High

Value Lost

s State Be

Infrastructure at Risk

3 Limited Access

Torrey Pines Community

- CA Dept. of Boating & Waterways e Torrey Pin

2 Storm Surge Damage

“Allowing the beach to retreat landward unimpeded can help support the existing beach width without the added costs of nourishment, safeguarding the recreational and habitat services that are threatened when the backbeach is armored.”

Projected Sea level

Infrastructure Loss

1” = 600’

52

Existing Regional Circulation

Proposed Regional Circulation

North park entry Wetland park Soft edge & trail system Restored dune system

Future train realignment

Trail & floating boardwalk South park entry

Streams 53

Trails

Roads

Train

State Preserve

Building Footprints

1� = 3,000’

54

Design

55

Disperse

Accumulate

Connect

To key locations

To restore and grow

To promote accessibility

56

Adapting Circulation The Torrey Pines State Preserve will no longer be a pass though space, but a destination park for the city of San Diego. Currently this state park is dominated by infrastructure that inhibits the coastal processes necessary for the gradual adaptation of this site in response to accelerated sea level rise and other anthropogenic forces.

The loss of these infrastructure pieces are eminent, whether it is 50 years from now or 100

years from now, the sea level will rise. We need to start making tough decisions now. Do we hold the line and build higher and stronger? Or do we allow the inevitable to take place and start preparing and transitioning now?

It is clear that the later strategy will bring the most benefit for the ecological processes of the lagoon and for maintaining public space and accessibility for the people of the region.

Treating the preserve as a DESTINATION, not a pass through space...

Existing Circulation

Proposed Circulation

Trail Path Elevated Boardwalk Floating Boardwalk Road

State Preserve Boundary 57

Vehicular & Train Circulation

1� = 1,200’

58

Master Plan

Projected Sea Level Rise [2 m] 59

Current High Water Level

Future High Water Level

1� = 1,200’

60

Sediment Dispersal Strategy A key element to this adaptation strategy is using the sediment that accumulates at the mouth of the lagoon in smarter ways. Instead of dispersing sediment solely to the beach front where it gets washed away, sediment can be invested in the lagoon.

the use of this sediment throughout the site:

1) restoration of the north parking lot to a beach and experimental marsh zone 2) Along the neighborhood edge to create more gradual slopes for marsh migration 3) Thin layer placement of sediment along the Approximately 50,000 cy of sediment is removed spine of the train tracks for marsh migration 4) Inland dune strengthening and restoration in annually from the lagoon mouth. The different strategies described in the adaptation plan rely on preparation for the eventual removal of the road Beach Lot

k

r Pa

Removed Annually

e at St

50,000 yd

3

2030

Torrey Pines Community

try

ail Tr

500,000 yd3

En

ain Tr

2020

Re

gio

2040 2050

na

lT rai l

2060 BEACH LOT

2080

NEIGHBORHOOD

500,000 yd3

700,000 yd3

2090

tin

oa Fl

MARSH 1,800,000 yd3

g

1,500,000 yd3

Los Peñasquitos Lagoon

une

State Beach

DUNE

Restored D

s Torrey Pine

2070

ail Tr 1” = 500’

61

62

0 ft

1 ft

2 ft

3 ft

4 ft

5 ft

Sea Level Rise

Beach Width

6 ft

Beach Access

2100 ?

120’

Winter

65’

Summer What Beach?

0’

Flood Risk (annual)

1%

5%

15 %

50 %

100 %

100 %

100 %

13 12

Lagoon (ft NAVD)

11 10

Upland

Marsh?

9 8 7 6 5 4

Transition Marsh

3

Subtidal

2 1 0

Adaptation Strategy

Dune Restoration

Lagoon Trail Connection

Dune Migration

Beach Lot

Sediment Capture

Marsh Migration

Marsh Nourishment

Marsh Nourishment

Neighborhood Retreat

Marsh/Upland Restoration

Train Realignment

Public Access

Train Removal Coast Highway Removal

63

64

Sediment Dispersal

Constructed Wetlands

each

es State B

Torrey Pin

500,000 yd3

Parking Lot & Entry Ca

rm

el

Va ll

ey

Rd

NR

SA

S LO

way 101

h Coast Hig ail r

do

rri

Co

Projected Sea level 65

Infrastructure Loss

1” = 2,500’

66

State Beach Entrance With the conversion of the parking lot to a beach space, a new entrance to the park at a higher elevation will need to be constructed. The park entrance will include terraced wetland treatment zones that accommodate rain water from the neighborhood and upland road infrastructure. Previously the rain water went directly from the road to the sewer system and into the lagoon.

The wetland park also serves as a stopping point along the regional bike path to access the neighborhood or beach.

67

68

Terraced Fresh Water Wetland The terraced wetland serves as the main feature of the new entry point to the park. As visitors make their way along the regional trail or enter from the neighborhood they witness the transition from fresh to salt water. The elevated boardwalk gives direct access to the beach and floating boardwalk, as well as providing a view over the terraced wetland.

Native plantings along the wetland beds treat stormwater prior entering the salt marsh and can withstand long drought periods. This method of

stormwater runoff treatment serves as an example to the neighborhood and can be duplicated throughout the watershed and region to improve water quality.

Wetland Vegetation Emergent

In the next century the terraced wetland will also mark the rise of sea level. The elevated boardwalk will still provide access to the beach and water even after the regional trail and terraced marsh is under water.

Mexican Rush Juncus Mexicana

California Gray Rush Jucus patens

Yarrow Achillea millefolium

Rusty Sedge Carex subfusca

Thin Grass Agrostis palens

Scarlet Monkeyflower Mimulus cardinalis

Upland

Circulation

Rest Stop marsh Boardwalk Elevated

Trail

Marsh

marsh

Neighborhood Access

Terraced Wetland

Rain Water Flow

Bike & Pedestrian Trail

marsh To the Beach!

Trail

Train

Floating Dock

Picnic Area

Regional

Beach Lot

Deergrass Muhlenburgia rigens

To the Beach!

To Marsh Trail

69

70

Terraced Fresh Water Wetland

B A

A

Salt Marsh

Upland Vegetation

Bike Path

Rock Filter

Wetland Treatment

Path

B

Salt Marsh

71

Upland Vegetation

Bike Path

Picnic Area

Wetland Treatment

Path

72

Regional Trail & Picnic Area

73

74

Beach Lot Design The beach lot design is the first step in transitioning at risk infrastructure into public and habitat space. An initial distribution of sediment would create a gradual sloped beach. Terraced rings of rip-rap and beach pebbles will help establish every 1 foot rise in elevation. These materials are already existing along the parking lot edge and through excavation. Overtime, the movement of the lagoon inlet will transform the landscape and turn this area into a dynamic space

Sediment Capture

for viewing the daily and long term effect of sea level rise. Initially, people will be able to access the beach lot from the current road. In approximately 20 years, a pedestrian boardwalk will need to be constructed that allows people to access the beach and get a closer look at the lagoon inlet.

Site Materials

Upper Level Dune

High Tide Inundation

Low Tide

75

76

Models

Site Textures & Materiality

01 Orthogonal

02 Rectilinear

03 Rectilinear

04 Biomorphic

05 Pools

77

78

View of Beach Lot from Elevated Boardwalk High Tide

Low Tide

Open Water

79

80

Floating Boardwalk

81

82

0 ft

1 ft

2 ft

3 ft

4 ft

5 ft

Sea Level Rise

Beach Width

6 ft

Marsh Trail

2100 ?

120’

Winter

65’

Summer What Beach?

0’

Flood Risk (annual)

1%

5%

15 %

50 %

100 %

100 %

100 %

13 12

Lagoon (ft NAVD)

11 10

Upland

Marsh?

9 8 7 6 5 4

Transition Marsh

3

Subtidal

2 1 0

Adaptation Strategy

Dune Restoration

Lagoon Trail Connection

Dune Migration

Beach Lot

Sediment Capture

Marsh Migration

Marsh Nourishment

Marsh Nourishment

Neighborhood Retreat

Marsh/Upland Restoration

Train Realignment

Public Access

Train Removal Coast Highway Removal

83

84

Marsh Nourishment

Trail Buffer

Constructed Wetlands

Rolling Easement

Car

me

l Va

lley

Rd

700,000 yd3

S LO NR

SA ail rri

Co r do

Projected Sea level 85

Infrastructure Loss

1” = 2,500’

86

Neighborhood Edge Camino del Sur road along the north edge of the lagoon will be completely flooded after 3-4 ft of sea level rise. This will also extend into the first row of properties as seen in the current condition axon below.

the same location, this area now becomes part of the state preserve. Sediment will be introduced to restore a gradual slope for marsh migration and a trail system will be constructed along the higher elevation near the remaining homes.

With the rolling easement in place, these properties will be uninhabitable once they are within the MHHW elevation mark. Instead of reconstructing higher roads and redevelopment in

The upper level trail will serve as a bicycle and pedestrian transit way that links into the end of existing residential streets. The lower footpath will bring people closer to the dynamic lagoon ecology.

Current Condition with Projected SLR Businesses & Homes Flooded

Road Submerged

26’ 24’

22’

20’

18’

16’ 14’

87

12’

88

Marsh Trail Typologies The lower marsh trail is designed to be floodable and easily adaptable to the rise of sea level and the daily fluctuation of tides. This is made possible by the movable platforms that serve as markers along the trail and floatable boardwalks. Benches and informational signage can also be attached to these platforms to enhance the visitor experience.

Additionally, elevated commercial nodes can be established along the intersection of cul-de-sac and the marsh. With views into the open marsh this provides a welcoming space for people to gather and grab a bite to eat.

Static

Mid-Century Trail System Bike & Pedestrian Trail

Dynamic Marsh Trail

26’ 24’

22’ 20’

18’

16’

14’ 16’

14’

Flood Channel

Nearing the end of the century the lower trail can be moved higher in elevation and closer to the neighborhood edge. Platforms can also serve as floating wetlands for improved habitat and trail experience.

Floating Boardwalk

End-Century Trail System Restaurant or Commercial Development

Floating Boardwalk

26’ 24’

22’ 20’

18’ 16’

18’16’

14’

12’

10’

Floating Marsh

89

90

Marsh Trail

Striped Shore Crab Pachygrapsus crassipes

91

92

0 ft

1 ft

2 ft

3 ft

4 ft

5 ft

Sea Level Rise

Beach Width

6 ft

Train Trail

2100 ?

120’

Winter

65’

Summer What Beach?

0’

Flood Risk (annual)

1%

5%

15 %

50 %

100 %

100 %

100 %

13 12

Lagoon (ft NAVD)

11 10

Upland

Marsh?

9 8 7 6 5 4

Transition Marsh

3

Subtidal

2 1 0

Adaptation Strategy

Dune Restoration

Lagoon Trail Connection

Dune Migration

Beach Lot

Sediment Capture

Marsh Migration

Marsh Nourishment

Marsh Nourishment

Neighborhood Retreat

Marsh/Upland Restoration

Train Realignment

Public Access

Train Removal Coast Highway Removal

93

94

Sediment Dispersal

Marsh Nourishment

1,800,000 yd

Car

me

3

l Va

lley

Rd

S LO NR

SA ail rri

Co r do

Projected Sea level 95

Infrastructure Loss

1” = 2,500’

96

Train Trail & Marsh Nourishment Between 2070 - 2080 portions of the LOSSAN rail corridor will become flooded within the lagoon. In preparation for this, the rail line will be diverted along and under the existing Interstate 5 Freeway. Removing the train form this alignment opens new possibilities for marsh migration along the corridor.

be converted into a trail system that links the north beach to the southeastern portion of the lagoon. A combination of floating boardwalks and land trails can be installed overtime to create this new regional link to the lagoon and beach.

Thin layer placement of sediment overtime helps to create higher areas within the marsh for potential marsh migration and higher elevations for bird nesting sites. The train berm and existing tracks can

Train Removal

Train Trail

Rip Rap

6’

26’ 10’ 6’

97

98

Thin Layer Placement Thin layer placement of sediment in coastal salt marshes is a relatively new sea level rise adaptation technique. Dispersing sediment throughout portions of coastal salt marshes can help marsh vegetation grow higher to keep up with sea level rise. There are many waterfowl species that rely on high marsh habitats for nesting. The vegetation within lagoons is also critical to cleaning polluted runoff water from the surrounding watershed before it enters the ocean.

can occur along the sides of the train tracks, where there is a berm. This linear application of thin layer placement is practical for protecting the neighborhood edge along the lagoon from storm surge. The berm of the train tracks also acts as a spine for sediment to be dispersed along. Low rip rap walls placed perpendicular to the train berm delineate regions for thin layer placement and provide access within the marsh for research and observation.

Marsh Regrowth Pedestrian Access

Marsh Growth

10’

26’ 12’ 10’

In the Los Peñasquitos Lagoon, thin layer placement

Sediment Application

Sediment Dispersal

Marsh Establishment Upland

10’

10’

26’ 12’

99

10’

Marsh Transition

26’ 12’ 10’

100

Sediment Regime The sediment regime is a necessary portion of adaptive management in on-going thin layer placement projects for both habitat and monetary reasons. It is important not to diminish the habitat quality of the marsh by covering too much surface area with sediment because it takes time for the vegetation to grow upward and re-establish itself. Applying sediment to a set few locations on a planned rotation is also more feasible for obtaining the necessary funding on an annual basis.

Implementation and monitoring of thin layer placement projects along the west coast are currently underway in marshes in San Francisco and Seal Beach. Through this research, a sediment regime can be established for successful regrowth of salt marsh vegetation after thin layer placement in other salt marsh adaptation projects.

20

20 10�

1 2

40

20

3

60

20

10�

0

101

1

2

3

102

Train Trail

Ridgway’s (Clapper) Rail Rallus longirostris levipes

103

104

0 ft

1 ft

2 ft

3 ft

4 ft

5 ft

Sea Level Rise

Beach Width

6 ft

Dune Restoration

2100 ?

120’

Winter

65’

Summer What Beach?

0’

Flood Risk (annual)

1%

5%

15 %

50 %

100 %

100 %

100 %

13 12

Lagoon (ft NAVD)

11 10

Upland

Marsh?

9 8 7 6 5 4

Transition Marsh

3

Subtidal

2 1 0

Adaptation Strategy

Dune Restoration

Lagoon Trail Connection

Dune Migration

Beach Lot

Sediment Capture

Marsh Migration

Marsh Nourishment

Marsh Nourishment

Neighborhood Retreat

Marsh/Upland Restoration

Train Realignment

Public Access

Train Removal Coast Highway Removal

105

106

Constructed Reef

Inland Dune Strengthening

Dune Restoration

Road Removal

es Torrey Pin ch State Bea Coast Hig hway 101

1,500,000 yd3

Projected Sea level 107

Infrastructure Loss

1” = 2,500’

108

Dune Restoration The dune restoration will be a continual adaptation strategy that can start now and continue until the coast highway is eventually removed. Instead of placing all of the sediment from the lagoon mouth on the beach, a portion can be allocated to the dune, and constructed reefs can be introduced to help capture sediment along the beach.

the movement of the mouth of the lagoon. Dune restoration and longevity of the beach is impossible without the eventual removal of the road. This will inhibit direct access by car, although the south parking lot will still be accessible and parking and bus access to the state park could be made available along the upland portion of the coast highway. The positive benefits that result from the removal of vehicular traffic greatly outweigh any issues that may arise with the diversion of traffic to the inland freeway.

Building the road higher is only a temporary measure that threatens the life of the beach and lagoon, as it prevents beach migration inland and constricts

Current Coast Highway & Beach Condition

Marsh Edge

Existing Road

Lifeguard Tower

6’ 18’

109

16’ 14’

8’

6’

4’

2’

110

Road Removal Using inland dune strengthening, the first phase of restoration includes building up the back side of the dune and establishing native dune vegetation for stabilization. This dune strengthening can continue as water levels rise in preparation for the eventual removal of the road.

access points can be created along the edge of the dune to allow people to observe the dune system safely, while preserving other areas solely for habitat.

Mid-Century Back Dune Strengthening

Marsh Edge

Added Sediment

Dune Vegetation

At this stage, another major dune restoration project would occur to ensure that the beach has reached a high enough elevation to function properly once the road is fully removed. With the dune restored, new

Existing Road

6’

Reef Structure

12’ 18’16’

14’

12’

10’

8’ 6’

4’

Dune Vegetation

Beach Evening Primrose Camissonia cheiranthifolia

Beach Morning Glory Calystegia soldanella

Existing Condition

Coast Woolly-heads Nemacaulis denudata var. denudata

Pink Sand Verbena Abronia umbellata

Seaside Heliotrope Heliotropium curassavicum

Silver Beach Bur Ambrosia chamissonis

Western Ragweed Ambrosia psilostachya

End-Century Road Removal Marsh Edge

Dune Vegetation

Viewing Deck

Wood Boardwalk

26’24’

3 ft Sea Level Rise

2’

22’

18’

16’

14’

12’

10’

8’

6’

4’

6.7 ft Sea Level Rise

111

112

Dune Restoration

California Least Tern Sterna antillarum browni

113

Western Snowy Plover Charadrius alexandrinus

114

Through anthropogenic forces our urban sprawl has confined dynamic hydrological systems into defined spaces. A separation between humans and landscape functions has formed in the past century, which has drastically reduced our ability to adapt to a changing environment. We are now left with remnant undeveloped land, which is highly managed to preserve certain ecosystem services.

Conclusion

Instead of fighting the changes that will occur with sea level rise, we need to reevaluate our connection to the water. Our ability to act now will decide whether or not we adapt to change or have to fight change because we waited to long to collaborate.

Adaptive management and planning for climate change relies on the prioritization and valuation of ecosystem services. Having an understanding for the historical ecology of urban streams and estuaries helps to predict how these vital systems will respond to predicted climate change scenarios so that resilient adaptation strategies can be developed.

The migration of wetlands will be essential to maintain the ecological and hydrological functions necessary for the urban fabric. This is where landscape architecture can play a key role in the planning and transition of the movement of wetland habitat, and also envisioning how people can use this new landscape in beneficial ways for recreation, health, and preservation of cultural heritage.

115

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Figures 1. View of Los Penasquitos Lagoon looking north Source: http://nobbync.smugmug.com/Around-San-Diego/Beaches/torreypines/122784607_5KtAA-L.jpg

18. Highway 101 in 1920s Source: http://www.gbcnet.com/ushighways/US101/101pics2a.html

2. Historic rendering of view overlooking Los Penasquitos Lagoon Source: http://www.sfei.org/HE_San_Diego_Lagoons

19. Vintage Highway 101 in 1961 Source: http://www.sandiegomagazine.com/San-Diego-Magazine/July-2013/Vintage-Highway-101/

3. Ocean Discovery Institute’s Wetland Exploration Program https://scripps.ucsd.edu/labs/sgiddings/ocean-discovery-institutes-wetland-exploration-program/

20. Fishing and Camping on Torrey Pines Beach 1941 Source: http://www.sandiegomagazine.com/Features/Vintage/

4. Mouth of Los Peñasquitos Lagoon being re-opened Source: http://media.sdreader.com/img/photos/2013/05/13/open_t670.jpg?b3f6a5d7692ccc373d56e40cf708e3fa67d9af9d

21. Lagoon Inlet during king tide Source: http://thehungryhydrologist.blogspot.com/2014/03/king-tides-part-2-san-diego-edition.html

5. Marsh Habitat Zones Source: http://www.amigosdebolsachica.org/birdsandscience.php

22. NOAA Sea Level Datums for La Jolla, CA Source: https://coast.noaa.gov/slr/

6. Leopard Shark Source: http://www.ashleyhauck.com/blog/wp-content/uploads/2012/07/20120731-IMG_3260-Edit.jpg

23. Scenarios of Sea Level Rise to 2100 Source: Dan Cayan, Scripps Institution of Oceanography, NCAR CCSM3 simulations, Rahmstorf method.

Heberger, Matthew et al. THE IMPACTS OF SEA-LEVEL RISE ON THE CALIFORNIA COAST. N.p., 2009.

7. Round Stingray Source: http://i.cdn-surfline.com/forecasters/2016/06_June/SR/SR2.jpg 8. Light Footed Clapper Rail Source: http://www.bird-friends.com/pics/ClapperRail/ClapperRail2LR.jpg 9. Western Snowy Plover Source: https://www.fws.gov/uploadedImages/Region_1/NWRS/Zone_2/Willapa_Complex/Willapa/Images/snowy-ploverenlarged-profi(1).jpg 10. Walking on the beach Source: https://media-cdn.tripadvisor.com/media/photo-s/01/3e/e1/ce/torrey-pines-beach.jpg 11. Hiking the cliffs Source: https://upload.wikimedia.org/wikipedia/commons/7/70/Torrey_Pines_cliffs.jpg 12. Surfing and swimming Source: http://4.bp.blogspot.com/-joTcBvO-lQ0/TgujulfUe5I/AAAAAAAADCA/thZzLUxicBw/s1600/6.JPG 13. Grabbing a burrito at Roberto’s Source: http://mysocaldlife.com/wp-content/uploads/2013/08/Robertos-San-Diego-Torrey-Pines.jpg 14. Torrey Pines State Beach Source: https://karmenvasion.com/2015/08/21/san-diego-california/#jp-carousel-3402 15. Historic Contour Map of Torrey Pines Region Source: http://www.sfei.org/HE_San_Diego_Lagoons 16. Kumeyaay of Southern California Source: http://www.kumeyaay.info/mobi/history/Kumeyaay.jpg 17. 1914–1915 Panoramic Automobile Road Map and Tourist Guide Book of Southern California Source: http://www.americanroads.us/forum/index.php?action=profile;area=showposts;u=1

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24. Wetland Intertidal Zones Source: Heberger, Matthew et al. THE IMPACTS OF SEA-LEVEL RISE ON THE CALIFORNIA COAST. N.p., 2009.

25. Vegetation transition Source: http://www.sfei.org/HE_San_Diego_Lagoons Low Marsh Species 26. Distichlis spicata Source: https://www.wildflower.org/plants/result.php?id_plant=DISP 27. Cuscuta salina Source: http://natureid.blogspot.com/2011/07/dodder-and-pickleweed-072211-elkhorn.html 28. Cressa truxillensis Source: http://nathistoc.bio.uci.edu/plants/Convolvulaceae/Cressa%20truxillensis.htm 29. Arthrocnemum subterminale Source: http://jaysullivan.org/pickwds2.htm High Marsh Species 30. Sarcocornia pacifica Source: https://www.sanelijo.org/plant-guide/pickleweed 31. Monanthochloe littoralis Source: http://nathistoc.bio.uci.edu/Plants%20of%20Upper%20Newport%20Bay%20(Robert%20De%20Ruff)/ Poaceae/Monanthochloe_littoralis_June.jpg 32. Jaumea carnosa Source: http://www.smmflowers.org/bloom/pics/S4955aMBC.jpg 33. Frankenia salina

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References Source: http://www.calflora.net/bloomingplants/images/alkaliheath10.jpg Transition/Upland Species 34. Typha sp.

Source: https://s-media-cache-ak0.pinimg.com/736x/61/63/81/6163818e5641dded5095f781f1fc8020.jpg 35. Polypogon monspeliensis Source: http://science.halleyhosting.com/nature/gorge/poaceae/polypogon/monspeliensis/monspeliensis1c.jpg 36. Lasthenia glabrata Source: http://calphotos.berkeley.edu/imgs/512x768/0000_0000/0509/1534.jpeg

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Mann, Michael E, and Peter H Gleick. “Climate Change and California Drought in the 21st Century.” Proceedings of the National Academy of Sciences of the United States of America 112, 13 (2015): 3858–3859.

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BARBIER, EDWARD B. et al. “The Value of Estuarine and Coastal Ecosystem Services.” Ecological Monographs 81, 2 (2011): 169–193.

37. Pterostegia drymarioides Source: http://nativeplants.csuci.edu/images/pterostegia-drymarioides-19feb2005-2.jpg 25. Marshland Zonation

Beller, Erin E., Sean Baumgarten, Robin M. Grossinger, T. Longcore, E. D. Stein, S. Dark, and Scott D. Dusterhoff. “Northern San Diego County Lagoons Historical Ecology Investigation.” San Francisco Estuary Institute. Coastal Conservancy, 01 Jan. 1970.

38. Coastal Marsh Formation and Cliff Erosion Source: (Meldahl)

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Cole, Kenneth L, and Eugene Wahl. “A Late Holocene Paleoecological Record from Torrey Pines State Reserve, California.”

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Kirwan, Matthew L et al. “Limits on the Adaptability of Coastal Marshes to Rising Sea Level.” Geophysical Research Letters 37 (September 2010): 1–5.

Greer, Keith, and Douglas Stow. “Vegetation Type Conversion in Los Peñasquitos Lagoon, California :An Examination of the Role of Watershed Urbanization.” Environmental Management 31, 4 (2003): 489–503.

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Meldahl, Keith Heyer. Surf, Sand, and Stone: How Waves, Earthquakes, and Other Forces Shape the Southern California Coast. Oakland, CA: U of California, 2015.

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“RANCHO PENASQUITOS - A HISTORY”. Friends of Los Peñasquitos Canyon Preserve. http://www.penasquitos.org/history. htm Strelich, Lily. “When Beach Nourishment Kills,” Hakai Magazine, April 20, 2016, accessed May 5, 2017, http://bit. ly/1U6ECXa.

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