Development of Regional Objectives for Southern …Development of Regional Objectives for Southern...

Development of Regional Objectives for Southern California Coastal Wetlands using

Landscape-level Metrics

Restore America’s Estuaries

December 13, 2016

Jeremy Lowe, San Francisco Estuary Institute

Upper Newport

1. Gaviota Coast

2. Ventura Coast

3. Santa Monica Bay

4. San Pedro Bay

5. San Diego Coast

Point ConceptionCounty Line (Santa Barbara/Ventura)

Santa Monica Mountains

Palos Verdes

Tijuana

San Onofre Mountains

1. Bight-wide objectives

2. Sub-regional objectives

3. Management recommendations

Southern California Bight

Habitat Losses

0%

10%

20%

30%

40%

50%

60%

70%

80%

90%

100%

Bight GaviotaCoast

VenturaCoast

SantaMonica Bay

San PedroBay

San DiegoCoast

Marine

Non-wetland

Non-tidal wetland

Different estuarine wetland

No change

Structure of Objectives

• Total Estuarine Area

• Habitat Distribution

• System Coherence

• Archetype Distribution

• Wetland Size

• Transition Zones

• Physical and Hydrologic Processes

Bolsa Chica

Historical Present

Total Estuarine Area

Tijuana

Present Future

Expand overall estuarine area toward historical levels, constrained by development with 0.6m sea level rise.

Total Estuarine Area

Tijuana

Total Estuarine Area

0

50

100

150

200

250

300

350

400

Historical Present UndevelopedExtent

Are

a (h

a)

Tidal Marsh

Intertidal Flat

Subtidal

Future: SLR 0.6m

Total Estuarine Area

Realize a total of 8300 ha by

maintaining the existing 4200 ha and

restoring an additional 4100 ha.

27%, 2270 ha

19%, 1570 ha

54%, 4480 ha

Area = 8320 ha

Subregion Restore

Gaviota Coast 280 ha

Ventura Coast 1660 ha

Santa Monica Bay 170 ha

San Pedro Bay 1160 ha

San Diego Coast* 810 ha

Bight 4100 ha

Habitat Distribution

Approximate the historic distribution of habitat types and provide redundancy of habitat types across systems in the region.

Ballona Santa Ana

Habitat Distribution

Subregion % Tidal flats % Marsh

Gaviota Coast 29% 50%

Ventura Coast 22% 63%

Santa Monica Bay 19% 71%

San Pedro Bay 26% 69%

San Diego Coast 35% 59%

Historically, estuarine wetlands were composed of 63% marsh, 29% flats and 8% subtidal in the Bight Region. Habitat distribution in the subregions should be made up of the following proportions:

Realize distribution of archetypes comparable to historical conditions in their appropriate locations within the subregion.

Bataquitos Lagoon Tijuana

Mission Bay

Bell Canyon Malibu

Archetype Distribution

Example - Maintain and enhance at least 10 small creeks in the subregion.

Example - Maintain 6 lagoon or estuary systems in the Gaviota region.

Gaviota Coast Gaviota State Park

System Coherence

Historic Santa Ana River Mouth System Current fragments include Santa Ana River, Santa Ana River Wetlands and Talbert Marsh

Maintain coherence of existing systems.Reconnect currently fragmented systems and to their watersheds.

Wetland Size

0

10

20

30

40

50

60

0-20 ha 20-50 ha 50-100 ha 100-200 ha 200-300 ha 300-400 ha 400-500 ha 500-750 ha 750-1000 ha 1000+ ha

Historic Present 2050 Undeveloped Constrained

Ensure adequate patch size distribution of systems

Transition Zones

Elevation Public ownership

Enhance connectivity with upland habitats and maintain existing transition areas.

San Dieguito San Dieguito

Physical and Hydrologic Processes

• Support internal structure and habitats in other objectives.

• Include structural elements that were present historically.

• Objectives are related, and cannot be accomplished in isolation.

1. Restore tidal prism and residence time

2. Reduce coastal jetties

3. Manage water and sediment inflow

Upper Newport

Summary of objectives

1. Total estuarine area is based on future projections.

2. Habitat distribution is based upon historical mapping.

3. Maintain archetype distribution in subregions.

4. Reconnect fragmented systems guided by historical archetype.

5. Increase system sizes generally.

6. Maintain existing and restore additional transition zones.

7. Maintain and enhance physical and biological processes.

Thank you

Carpinteria