Santa Monica Airport Watershed Management Project

Santa Monica Airport Watershed Management Project City of Santa Monica

Project No. 1CSM030100

February 2008

Prepared for:

City of Santa Monica

1437 4th St.

Suite 300 Santa Monica, CA 90401

Prepared by:

555 S. Flower Street, Suite 4400

Los Angeles, CA 90071

Catherine Tyrrell

with

GeoSyntec Consultants

2566 Overland Avenue, Suite 670

Los Angeles, CA 90064

Ken Susilo

Santa Monica Airport Watershed Management Project

February 2008 i

TABLE OF CONTENTS

TABLE OF CONTENTS .................................................................................................. i

TABLES.............................................................................................................................. i

FIGURES............................................................................................................................ i

APPENDICES.................................................................................................................. iii

1.0 Introduction and Summary .............................................................................. 1-1 1.1 Approach.......................................................................................................... 1-1

1.2 City of Santa Monica Airport Watershed Project Site Description .............. 1-2

1.3 Drainage Areas and Land Use Opportunities and Constraints ........................ 1-4

1.4 Key BMPs and Treatment Trains .................................................................... 1-5

2.0 Pollutants of Concern ........................................................................................ 2-5 2.1 Pollutants and Beneficial Uses in Receiving Waters....................................... 2-5

2.2 Land Uses and Associated Pollutants .............................................................. 2-6

3.0 Airport Watershed Description ...................................................................... 3-11 3.1 Physical Description of Watershed................................................................ 3-11

3.2 Drainage Sub-Areas ....................................................................................... 3-13

3.3 Land Uses, Pollutants, and BMP Opportunities and Constraints .................. 3-15

4.0 BMPs Evaluated............................................................................................... 4-59 4.1 Stakeholder Workshop................................................................................... 4-59

4.2 BMP List for Further Analysis ...................................................................... 4-59

4.3 Worksheets and Photos—Feasibility at a Planning Scale.............................. 4-61

4.3.1 AIRPORT PROPERTY......................................................................... 4-61

4.3.2 RESIDENTIAL AREA.......................................................................... 4-64

4.3.3 BUSINESS PARK................................................................................. 4-69

4.3.4 OTHER .................................................................................................. 4-70

4.4 Amounts and values of Avoided Potable Water Use..................................... 4-71

5.0 Next Steps ......................................................................................................... 5-71 5.1 Capital Improvement Plan ............................................................................. 5-71

6.0 Conclusion ........................................................................................................ 6-71

TABLES

Table 2-1 Land Uses and Associated Pollutants.............................................................. 2-6

Table 2-2 BMPs and Targeted Pollutants ........................................................................ 2-9

Table 3-1 Sub-Drainage Description and Tributary Areas ............................................ 3-13

Table 3-2 LAND USE BMP ASSESSMENT: ISSUES AND OPPORTUNITIES ...... 3-16

Table 4-1 Water Quality Calculations Summary........................................................... 4-60

FIGURES

Figure 1-1......................................................................................................................... 1-2

Figure 1-2......................................................................................................................... 1-3

Figure 1-3......................................................................................................................... 1-4

Figure 3-1....................................................................................................................... 3-11


February 2008 ii

Figure 3-2....................................................................................................................... 3-12

Figure 3-3....................................................................................................................... 3-14

Figure 3-4....................................................................................................................... 3-15

Figure 3-5....................................................................................................................... 3-23

Figure 3-6....................................................................................................................... 3-23

Figure 3-7....................................................................................................................... 3-24

Figure 3-8....................................................................................................................... 3-24

Figure 3-9....................................................................................................................... 3-25

Figure 3-10..................................................................................................................... 3-25

Figure 3-11..................................................................................................................... 3-26

Figure 3-12..................................................................................................................... 3-26

Figure 3-13..................................................................................................................... 3-27

Figure 3-14..................................................................................................................... 3-27

Figure 3-15..................................................................................................................... 3-28

Figure 3-16..................................................................................................................... 3-28

Figure 3-17..................................................................................................................... 3-29

Figure 3-18..................................................................................................................... 3-29

Figure 3-19..................................................................................................................... 3-30

Figure 3-20..................................................................................................................... 3-30

Figure 3-21..................................................................................................................... 3-31

Figure 3-22..................................................................................................................... 3-32

Figure 3-23..................................................................................................................... 3-33

Figure 3-24..................................................................................................................... 3-33

Figure 3-25..................................................................................................................... 3-34

Figure 3-26..................................................................................................................... 3-34

Figure 3-27..................................................................................................................... 3-35

Figure 3-28..................................................................................................................... 3-35

Figure 3-29..................................................................................................................... 3-36

Figure 3-30..................................................................................................................... 3-36

Figure 3-31..................................................................................................................... 3-37

Figure 3-32..................................................................................................................... 3-37

Figure 3-33..................................................................................................................... 3-38

Figure 3-34..................................................................................................................... 3-38

Figure 3-35..................................................................................................................... 3-39

Figure 3-36..................................................................................................................... 3-39

Figure 3-37..................................................................................................................... 3-40

Figure 3-38..................................................................................................................... 3-40

Figure 3-39..................................................................................................................... 3-41

Figure 3-40..................................................................................................................... 3-41

Figure 3-41..................................................................................................................... 3-42

Figure 3-42..................................................................................................................... 3-42

Figure 3-43..................................................................................................................... 3-43

Figure 3-44..................................................................................................................... 3-43

Figure 3-45..................................................................................................................... 3-44

Figure 3-46..................................................................................................................... 3-44

Figure 3-47..................................................................................................................... 3-45


February 2008 iii

Figure 3-48..................................................................................................................... 3-45

Figure 3-49..................................................................................................................... 3-46

Figure 3-50..................................................................................................................... 3-46

Figure 3-51..................................................................................................................... 3-47

Figure 3-52..................................................................................................................... 3-47

Figure 3-53..................................................................................................................... 3-48

Figure 3-54..................................................................................................................... 3-48

Figure 3-55..................................................................................................................... 3-49

Figure 3-56..................................................................................................................... 3-49

Figure 3-57..................................................................................................................... 3-50

Figure 3-58..................................................................................................................... 3-50

Figure 3-59..................................................................................................................... 3-51

Figure 3-60..................................................................................................................... 3-51

Figure 3-61..................................................................................................................... 3-52

Figure 3-62..................................................................................................................... 3-52

Figure 3-63..................................................................................................................... 3-53

Figure 3-64..................................................................................................................... 3-53

Figure 3-65..................................................................................................................... 3-54

Figure 3-66..................................................................................................................... 3-54

Figure 3-67..................................................................................................................... 3-55

Figure 3-68..................................................................................................................... 3-55

Figure 3-69..................................................................................................................... 3-56

Figure 3-70..................................................................................................................... 3-56

Figure 3-71..................................................................................................................... 3-57

Figure 3-72..................................................................................................................... 3-58

Figure 4-1....................................................................................................................... 4-61

Figure 4-2....................................................................................................................... 4-62

Figure 4-3....................................................................................................................... 4-63

Figure 4-4....................................................................................................................... 4-65

Figure 4-5....................................................................................................................... 4-66

Figure 4-6....................................................................................................................... 4-67

Figure 4-7....................................................................................................................... 4-69

Figure 4-8....................................................................................................................... 4-70

APPENDICES

Appendix A Technical Memorandum

Appendix B Penmar Water Quality Improvement and Runoff Reuse Project

Appendix C County Department of Health and Services and City Building and

Safety Division Health Standards

Appendix D Recommended BMPs Design Performance

Appendix E Workshop Presentation – 6/20/2007


February 2008 iv


1-1 February 2008

1.0 Introduction and Summary

This report builds upon the City of Santa Monica’s citywide Watershed Management

Plan focusing on a priority watershed, the Santa Monica Airport Watershed, creating a

more detailed Airport Watershed Management Plan with the following goals:

♦ Recommend implementable BMPs consistent with the City’s Hierarchy of BMPs:

◊ Harvest, treat and reuse

◊ Harvest and infiltrate

◊ Treat and release

♦ Support the restoration of a healthier balance between the urban environment and the natural ecosystem, including the Santa Monica Bay;

♦ Be consistent with the City’s guiding principles for sustainability.

Specifically the report is based on the following tasks:

• Evaluate and develop alternative solutions for runoff management and present and discuss these alternatives in a workshop coordinated by city staff; opportunities

for reuse will be included.

• Based on feedback from the workshop, provide an analysis of up to 10 BMPs in terms of construction constraints and costs, pollutants targeted, site feasibility

based on information available (planning level). At least one of the BMPs will

include down stream reuse opportunities.

• For the pertinent BMPs, provide information on treatment design and performance.

• Present information on the volume of water that can be reused and the avoided cost of potable water that it is replacing.

1.1 Approach

To initiate the project, background information was provided by the City of Santa

Monica, including the 1998 Hydrology Study, 1985 Master Plan of Drainage for the

Santa Monica Municipal Airport, the 2005 Draft Santa Monica Airport Watershed

Management Plan, and the Airport SWPPP and Monitoring Program. Information on soil

type and porosity was provided in the Santa Monica Municipal Airport Master Plan of

Drainage. FAA rules and regulations were considered in assessing potential best

management practices BMPs for the airport drainage area. Specifically, the 1984 Santa

Monica Airport Agreement with the Federal Aviation Administration (FAA) was

reviewed for regulations on the types of improvements that may take place on the airport

runway area. Restrictions include the runway/taxiway configuration, aircraft parking and

tie-down space, and fixed base operator space, among others.


February 2008 1-2

1.2 City of Santa Monica Airport Watershed Project Site Description

The Airport Watershed is located in the southeastern corner of Santa Monica. It includes

the Santa Monica Airport and surrounding both single family and multi-family residential

land use, with a small amount of commercial areas and parks. The Airport Watershed,

including the airport itself, totals about 565.5 acres. The watershed flows to the Rose

Ave. Drain in the City of Los Angeles and from there to Santa Monica Bay. Figure 1-1

shows the Santa Monica Airport Watershed.

Figure 1-1

Santa Monica Airport Watershed Site Map


February 2008 1-3

As shown in Figure 1-2, the Santa Monica Airport Watershed is part of a larger

watershed all of which drains to the Rose Ave. storm drain adjacent to Penmar Park and

Golf Course and exits to Santa Monica Bay. It is joined by the 16th Ave. storm drain

from within the city of Santa Monica and other city of Los Angeles Mar Vista hillside

and Penmar –adjacent drainage.

Figure 1-2

Rose Ave Drainage Area Including the Santa Monica Airport Watershed

Within the Santa Monica Airport Watershed, land uses can be seen in Figure 1-3.


February 2008 1-4

Figure 1-3

Land Uses Within the Santa Monica Airport Watershed

1.3 Drainage Areas and Land Use Opportunities and Constraints

The Santa Monica Airport Watershed is composed of four drainage areas within the City.

These are described in section 3.2. Section 3.3 provides the analysis of BMP

opportunities and constraints.

The watershed has been analyzed to determine locations for storm water reuse, retention,

detention, and treatment.


February 2008 2-5

1.4 Key BMPs and Treatment Trains

Based on a stakeholder workshop held on June 20, 2007, 10 BMPs were chosen for more

detailed analysis. They are:

Airport Property:

1. Airport Avenue Landscaping 2. SMC Parking Lot Underground Retention 3. Zinc Hangar Runoff Management

Residential Area:

4. Traffic Calming Landscape Modification 5. Pearl Street Rain Gardens 6. Grant Elementary School Underground Retention 7. Clover Park Underground Retention 8. Pico Boulevard Porous Pavement

Business Park:

9. Business Park Bioretention Retrofit

Other:

10. Penmar Water Quality Improvement and Runoff Reuse

2.0 Pollutants of Concern

2.1 Pollutants and Beneficial Uses in Receiving Waters

The Santa Monica Airport Watershed is part of the greater Rose Ave. Watershed which,

in turn, is part of the 414 square-mile Santa Monica Bay Watershed. The Santa Monica

Bay Watershed reaches from the crest of the Santa Monica Mountains on the north from

the Ventura-Los Angeles County line to downtown Los Angeles. From there it extends

south and west across the Los Angeles plain to include the area east of Ballona Creek and

north of Baldwin Hills. South of Ballona Creek, the natural drainage area is a narrow

strip between Playa del Rey and Palos Verdes.

The Santa Monica Bay has many beneficial uses, including fishing, swimming, surfing,

diving and other REC-1 classified activities. Santa Monica Bay Beaches also have

separate beneficial uses. The Los Angeles Regional Water Quality Control Board’s 2002

Clean Water Act Section 303(d) List includes the Santa Monica Bay Offshore/Nearshore.

The pollutants listed for this area include:

◊ Chlordane (sediment)


February 2008 2-6

◊ DDT (tissue & sediment)

◊ Debris

◊ Fish Consumption Advisory

◊ PAHs (Sediment)

◊ PCBs Polychlorinated biphenyls (tissue & sediment)

◊ Sediment Toxicity

All are listed as low TMDL priority, with the exception of Chlordane which is listed as

medium.

The Santa Monica Bay Offshore/Nearshore pollutants listed on the 2006 303 (d) list

includes a shorter list of the following pollutants: DDT (tissue and sediment), Debris,

Fish Consumption Advisory, PCBs (Polychlorinated biphenyls) (tissue and sediment),

and Sediment Toxicity.

The beaches of Santa Monica Bay are listed separately from the receiving waters. The

key pollutant listed is coliform (bacteria).The Santa Monica Bay Beaches Bacteria Total

Maximum Daily Load (TMDL) was adopted on December 12, 2002 by the Regional

Board (Resolution No. 2002-022).

As a result of these listings, the pollutant of greatest concern is bacteria.

2.2 Land Uses and Associated Pollutants

Typical pollutants are associated with types of development (land use) that contribute to urban runoff. Table 2-1 below provides an overview of various land use classifications and the degree to

which specified pollutants may be expected as a result of each land use.

Table 2-1 Land Uses and Associated Pollutants

Type of

Development

(Land Use)

Sediment/

Turbidity

Nutrients Organic

Compounds

Trash

&

Debris

Oxygen

Demanding

Substances

Bacteria

&

Viruses

Oil &

Grease

Pesticides Metals

Detached

Residential

Development

E E N E E E E E N

Attached

Residential

Development

E E N E P (1) P P (2) E N

Commercial/

Industrial

P (1) P (1) P(5) E P (1) P(3) E P (1) P

Automotive

Repair Shops

N N E(4,5) E N N E N P

Restaurants N N N E E E E N N

Hillside

Development

E E N E E E E E N


February 2008 2-7

Parking Lots P(1) P(1) E(4) E P(1) P(6) E P(1) E

Streets,

Highways &

Freeways

E P(1) E(4) E P(1) P(6) E P(1) E

Parks and

Open Space

E E N N E N N E N

Source: Riverside County Flood Control and Conservation District, Riverside County Water Quality

Management Plan for Urban Runoff (September 17, 2004).

Abbreviations:

E = Expected P = Potential N=Not expected

Notes:

(1) A potential pollutant if landscaping or an open area exists. (2) A potential pollutant if area includes uncovered parking areas. (3) A potential pollutant is land use involves animal waste. (4) Specifically, petroleum hydrocarbons. (5) Specifically, solvents. (6) Bacterial indicators are routinely detected in pavement runoff.

The following descriptions are provided for each pollutant identified in Table 2-1 above:

� Sediments – Sediments are soils or other surficial materials eroded and then transported or

deposited by the action of wind, water, ice, or gravity. Sediments can increase turbidity, clog

fish gills, reduce spawning habitat, lower young aquatic organisms survival rates, smother

bottom dwelling organisms, and suppress aquatic vegetation growth.

� Nutrients – Nutrients are inorganic substances, such as nitrogen and phosphorus. They

commonly exist in the form of mineral salts that are either dissolved or suspended in water.

Primary sources of nutrients in urban runoff are fertilizers and eroded soils. Excessive

discharge of nutrients to water bodies and streams can cause excessive aquatic algae and

plant growth. Such excessive production, referred to as cultural eutrophication, may lead to

excessive decay of organic matter in the water body, loss of oxygen in the water, release of

toxins in sediment, and the eventual death of aquatic organisms.

� Organic Compounds – Organic compounds are carbon-based. Commercially available or

naturally occurring organic compounds are found in pesticides, solvents, and hydrocarbons.

Organic compounds can, at certain concentrations, indirectly or directly constitute a hazard to

life or health. When rinsing off objects, toxic levels of solvents and cleaning compounds can

be discharged to the MS4. Dirt, grease, and grime retained in the cleaning fluid or rinse water

may also adsorb levels of organic compounds that are harmful or hazardous to aquatic life.

Pesticides (including herbicides) are chemical compounds commonly used to control

nuisance growth or prevalence of organisms. Excessive or improper application of a pesticide

may result in runoff containing toxic levels of its active ingredient.

� Trash and Debris – Trash (such as paper, plastic, polystyrene packing foam, and aluminum

materials) and biodegradable organic matter (such as leaves, grass cuttings, and food waste)

are general waste products on the landscape. The presence of trash and debris may have a

significant impact on the recreational value of a water body and aquatic habitat. Excess

organic matter can create a high biochemical oxygen demand in a stream and thereby lower

its water quality. In addition, in areas where stagnant water exists, the presence of excess


February 2008 2-8

organic matter can promote septic conditions resulting in the growth of undesirable

organisms and the release of odorous and hazardous compounds such as hydrogen sulfide.

� Oxygen-Demanding Substances – This category includes biodegradable organic material as

well as chemicals that react with dissolved oxygen in water to form other compounds.

Proteins, carbohydrates, and fats are examples of biodegradable organic compounds.

Compounds such as ammonia and hydrogen sulfide are examples of oxygen-demanding

compounds. The oxygen demand of a substance can lead to depletion of dissolved oxygen in

a water body and possibly the development of septic conditions.

� Pathogens – Pathogens and viruses ( measured by bacteria indicators) are ubiquitous

microorganisms that thrive under certain environmental conditions. Their proliferation is

typically caused by the transport of animal or human fecal wastes from the watershed. Water,

containing excessive bacteria and viruses can alter the aquatic habitat and create a harmful

environment for humans and aquatic life. Also, the decomposition of excess organic waste

causes increased growth of undesirable organisms in the water.

� Metals – The primary source of metal pollution in urban runoff is typically commercially

available metals and metal products. Metals of concern include cadmium, chromium, copper,

lead, mercury, and zinc. Lead and chromium have been used as corrosion inhibitors in primer

coatings and cooling tower systems. Metals are also raw material components in non-metal

products such as fuels, adhesives, paints, and other coatings. At low concentrations naturally

occurring in soil, metals may not be toxic. However, at higher concentrations, certain metals

can be toxic to aquatic life. Humans can be impacted from contaminated groundwater

resources, and bioaccumulation of metals in fish and shellfish. Environmental concerns,

regarding the potential for release of metals to the environment, have already led to restricted

metal usage in certain applications.

A comparison of the pollutants existing in the Santa Monica Watershed and receiving

waters of the Santa Monica Bay with pollutants associated with land use activity in the

Santa Monica Airport Watershed shows an overlap of common pollutants.

Because of the wide range of land uses in the Santa Monica Airport Watershed, all of the

pollutants listed can be considered of concern in the Watershed. However as BMPs are

identified by location, one or another of the land uses and their specific pollutants of

concern will dominate. In general the strategy is as follows: 1) where reuse is possible,

treat to remove all pollutants to a Title 24 equivalency; 2) otherwise provide filtration or

infiltration to remove bacteria and other pollutants in storm water.

Table 2-2 provides a list of treatment control BMP categories identifying their

effectiveness in treating various pollutants of concern.


2-9 February 2008

Table 2-2 BMPs and Targeted Pollutants

Treatment Control BMP Categories(9)

Pollutant of Concern

Veg. Swale /Veg. Filter Strips

Detention

Basins(2)

Infiltration Basins & Trenches/Porous

Pavement(3)(10)

Wet Ponds or Wetlands

Sand Filter or Filtration

Water Quality Inlets

Hydrodynamic Separator Systems

(4)

Manufactured/ Proprietary Devices

Sediment/Turbidity H/M M H/M H/M H/M L H/M (L for turbidity)

U

Yes/No?

Nutrients L M H/M H/M L/M L L U

Yes/No?

Organic Compounds U U U U H/M L L U

Yes/No?

Trash & Debris L M U U H/M M H/M U

Yes/No?

Oxygen Demanding Substances L M H/M H/M H/M L L U

Yes/No?

Bacteria & Viruses U U H/M U H/M L L U

Yes/No? YES

Oils & Grease H/M M U U H/M M L/M U

Yes/No?

Pesticides (non-soil bound) U U U U U L L U

Yes/No?

Metals H/M M H H H L L U

Yes/No?


2-10 February 2008

Abbreviations: L: Low removal efficiency M: Medium removal efficiency H: High removal efficiency U: Unknown removal efficiency

Notes: (1) Periodic performance assessment and updating of the guidance provided by this table may be necessary. (2) Includes grass swales, grass strips, wetland vegetation swales, and bioretention. (3) Includes extended/dry detention basins with grass lining and extended/dry detention basins with impervious lining. Effectiveness based upon minimum 36-48-hour

drawdown time. (4) Includes infiltration basins, infiltration trenches, and porous pavements. (5) Includes permanent pool wet ponds and constructed wetlands. (6) Includes sand filters and media filters. (7) Also known as hydrodynamic devices, baffle boxes, swirl concentrators, or cyclone separators. (8) Includes proprietary stormwater treatment devices as listed in the CASQA Stormwater Best Management Practices Handbooks, other stormwater treatment BMPs not

specifically listed in this report or newly developed/emerging stormwater treatment technologies. (9) Project proponents should base BMP designs on the Los Angeles County Stormwater Quality Best Management Practice Design Handbook. However, project

proponents may also wish to reference the California Stormwater BMP Handbook – New Development and Redevelopment (www.cabmphandbooks.com). The Handbook contains additional information on BMP operation and maintenance.

(10) Note: Projects that will utilize infiltration-based Treatment Control BMPs (e.g., Infiltration Basins, Infiltration Trenches, Porous Pavement) without an underdrain will need to demonstrate with a property/project specific soils report that the soils are of the appropriate porousity. The selection of a Treatment Control BMP (or BMPs) for the project must specifically consider the effectiveness of the Treatment Control BMP for pollutants identified as causing an impairment of Receiving Waters to which the project will discharge Urban Runoff.

http://www.cabmphandbooks.com/


3-11 February 2008

3.0 Airport Watershed Description

3.1 Physical Description of Watershed

The Airport Basin Watershed is located in the southeastern corner of Santa Monica. It

includes the Santa Monica Airport and both single-family and multi-family residential

land use with a small amount of commercial areas and parks. The watershed flows to the

Rose Avenue Drain in the City of Los Angeles and from there to Santa Monica Bay.

Figure 3-1 shows the Santa Monica Airport Watershed Project Site.

Figure 3-1

Santa Monica Airport Watershed Site Map


February 2008 3-12

As shown in Figure 3-2, the Santa Monica Airport Watershed drains to the Rose Avenue

storm drain adjacent to Penmar Park and Golf Course and exits to Santa Monica Bay. It

is joined by the 16th Avenue storm drain from within the city of Santa.

Figure 3-2

Rose Avenue Drainage Area Including the Santa Monica Airport Watershed

The Santa Monica Municipal Airport Master Plan of Drainage (May 1985) states that the

soils in the drainage area are classified as 013 and 014, according to the Los Angeles

County Flood Control District’s classification of soil types. Soil type 013 has a low

infiltration capacity and produces a maximum amount of runoff. Soil type 014 also

produces a relatively high rate of runoff. These soil types were a factor in determining the

feasibility of infiltration best management practices, as discussed in section 4.


February 2008 3-13

3.2 Drainage Sub-Areas

The Santa Monica Airport Watershed is composed of four drainage areas.

Table 3-1 Sub-Drainage Description and Tributary Areas

Sub-Area Description Area [ac]

DA 1 - 25th-S Airport 156.0

DA 2 - 25th-N Northern Residential and Business Park 207.6

DA 3 – 23rd Cloverfield / 23

rd Street Residential 161.8

DA 4 – 21st Western Reidential 40.2

Total - 565.5


February 2008 3-14

Figure 3-3

Santa Monica Airport Watershed Drainage Areas


February 2008 3-15

3.3 Land Uses, Pollutants, and BMP Opportunities and Constraints

Figure 3-4 shows the Airport Watershed land uses.

Figure 3-4

Santa Monica Airport Watershed Land Uses


3-16 February 2008

Table 3-2 LAND USE BMP ASSESSMENT: ISSUES AND OPPORTUNITIES

(Figures referred to follow the table)

LAND USE ISSUE/CONSTRAINTS OPPORTUNITY

Airport General Drainage Area 1 (DA1) - Airport

Asphalt /

Runways • Majority of

existing airport is

impervious

(Figure 3-5, 3-6,

3-7, 3-42, 3-43)

• Storm flows

currently flood

Airport Rd.

• Most of the

Airport runs into

the City of LA.

• Slurry Seal

performed

annually on

taxiways.

• Per 1984 FAA agreement, can not remove

asphalt on runway area (including taxiways

and infill areas).

• Runoff from plane washing areas needs to

be captured/treated. (Figure 3-6)

• Airplane tie-downs/airplane parking areas

are on leased land to the owners until 2015.

(Figure 3-11, 3-12

• Remove gunite area and create terracing to allow

runoff to percolate in vegetation. (Figure 3-7)

• Culvert at end drainage point has potential to

provide infiltration as treatment. (Figure 3-34, 3-

35, 3-36, 3-37)

• Slot drains with underground treatment vault

(vortex-type, separation screening units) near

culvert at end drainage point. (Figure 3-38, 3-39,

3-41)

Parking Lots • Impervious

parking lots

contribute

pollutants into

• Pollutants include heavy metals, trash and

debris, oil and grease, with potential for

nutrients and pesticides, sediments, and

oxygen demanding substances.

• Grass-crete near fire station

• Porous pavement, grass-crete, or underground

retention at Santa Monica City College parking

area (Figure 3-71, 3-72, 3-73).


February 2008 3-17


runoff. • Insert landscaping/vegetation in parking lot

medians to treat pollutants (Examples: Figure 3-

15, 3-16, 3-17)

Hangers • Metal roofs are

source of

pollution.

• Metal building/zinc roofs are a source of

metals pollution. (Figure 3-28, 3-31)

• Metal surfaces painted and maintained

• Possible use of planter boxes to capture and

infiltrate roof runoff. (Figure 3-77)

Outdoor Plane

Parking Areas

(Tie-down areas)

• The area is

mostly

impervious.

• Impervious plane parking areas contribute

oil and grease pollutants. (Figure 3-10, 3-

13, 3-40)

• Direct runoff to slot drains with underground

treatment vault (vortex-type, separation screening

units).

Restaurants • Grease and oil

from cooking,

and leftover food

may contribute

bacterial

pollutants.

• Pollutants include pathogens, trash and

debris, oil and grease, and oil demanding

substances.

• Direct runoff to slot drain to underground

treatment vault.

Fueling, Fuel

storage, oil

recycling Areas

• Oil recycling

areas are

provided onsite

near the plane

washing areas.

• Pollutants include heavy metals, organic

compounds, trash and debris, and oil and

grease.

• Adequacy of berming near oil recycling

areas needs to be evaluated. (Figure 3-29,

3-30, 3-32).

• Plane washing areas (Figure 3-14) and gas

station need to be reviewed for adequate

capture.

• Review berming procedures for runoff.

Airport Park • Newly

completed park

provides

• New Airport Park includes 4 infiltration

basins, permeable asphalt is included in

parking areas, and synthetic turf on soccer

• New park will serve as new infiltration site for a

portion of the Airport watershed (Figure 3-74, 3-

75, 3-76).


February 2008 3-18


treatment for

runoff.

fields. All runoff on new park site will be

infiltrated, therefore this amount of treated

runoff will reduce the total volume of water

needed to be treated by future BMPs.

Education

(College

building)





• Water reuse for landscape irrigation.

• Landscape surrounding education buildings.


February 2008 3-19


Residential/

Commercial

General Drainage Area 2 (DA2) – Northern Residential

Open Space

(Clover Park)

• Clover Park parking lot drains to

infiltration pit under park for treatment.

• Potential to store northern residential watershed in

Clover Park (Figure 3-49, 3-50, 3-51).

Education

(Elementary

School property)

• Often difficult to enter into agreement with

school districts to treat offsite stormwater.

• Potential to store portion of northern residential

watershed runoff (Figure 3-60, 3-61, 3-62, 3-63)

Open Space

(Recreational

Fields)

• Currently, the field closest to the airport

serves as a retention basin (Figure 3-49)

during large storms when capacity in the

39” line exceeds the downstream 24” line

capacity and water overflows into field.

• Ball fields can be used to treat, store, and reuse

runoff from neighborhoods and commercial

buildings (airport business park). (Figure 3-50)

Major Streets

(Ocean Park

Blvd.)

• Residential

runoff from

household

pollutants.

• Residential runoff, including pathogens,

nutrients, pesticides, sediments, trash &

debris, oxygen demanding substances.

(Figure 3-52, 3-53, 3-54, 3-55, 3-66, 3-67,

3-68, 3-69, 3-70)

• Combine traffic calming vegetation with

infiltration/bioretention areas (Figure 3-21, 3-22,

3-78)

• Curb extensions throughout neighborhood streets.

(Example: Figure 3-19, 3-20)

Smaller

Residential

Streets

• Residential

runoff from

household

pollutants.

• Residential runoff, including pathogens,

nutrients, pesticides, sediments, trash &

debris, oxygen demanding substances.

(Figure 3-18, 3-24, 3-25, 3-56, 3-57, 3-58,

3-59, 3-64, 3-65)

• Landscaping augmented with bioretention cells for

infiltration and storm water treatment along streets

and on residential properties. (Figure 3-23, 3-26)



3-78)



February 2008 3-20



Single-family

residential

• Residential

runoff from

household

pollutants.

• Pollutants include pathogens, nutrients,

pesticides, sediments, trash & debris,







Multi-family

Neighborhoods

adjacent to

Ocean Park Blvd

• Residential

runoff from

household

pollutants.

• Pollutants include nutrients, pesticides,

sediments, trash & debris, with potential

for pathogens, oxygen demanding

substances, oil & grease.





infiltration/bioretention areas (Figure 3-21, 3-22)



Education

(School building)

• There may be limitations to diverting

stormwater runoff to school areas due to

human health concerns for students.

• Potential to use school fields to store and treat

water from watershed. (Figure 3-60, 3-61, 3-62, 3-

63)

Commercial

(Airport

Business Park)





• Connect roof runoff to landscaping and planter

boxes.

Residential General Drainage Area 3 and 4 (DA3/4) – Southern and Western Residential

Single-family

residential

Residential Lots in

Single-family Areas • Pollutants include pathogens, nutrients,

pesticides, sediments, trash & debris,


• Area is hilly and may not be conducive to






February 2008 3-21


treatment approaches infiltration/bioretention areas (Figure 3-21, 3-22,

3-78)

Multi-family

Residential

Multi-family

Neighborhoods –

adjacent to Ocean

Park Blvd

• Pollutants include nutrients, pesticides,

sediments, trash & debris, with potential

for pathogens, oxygen demanding

substances, oil & grease.






3-78)


February 2008 3-22


Other General Other

Open Space Penmar Park and

Golf Course • Golf Course is owned by the City of Los

Angeles so would need to coordinate

potential BMPs included in the City of LA

Penmar Water Quality Improvement and

Runoff Reuse Project Concept Report.

(Figure 3-33, 3-46, 3-47)

• The City of Los Angeles has completed a concept

report for Penmar Golf Course that includes a

project that involves infiltration basins in Golf

Course and the adjacent ball fields. The project

may also include an impermeable pond for

retention on Golf Course and water reuse. Runoff

from the Airport watershed may be directed to the

Golf Course for treatment (Figure 3-45, 3-47, 3-

48).

Future

Enhancements/

Alternatives

• Funding is a constraint.

• Health standards and water quality

requirements for urban runoff treatment

and reuse are currently at Title 22

standards, however alternative

requirements may be proposed in the

future.

• Coat roofs and downspouts instead of using

zinc/copper for new development/redevelopment.

• Recycled Water used for toilets/urinals may be

implemented if meets Title 22 regulations.

• Proposed underground storage of storm water may

be used by fire department for fire fighting.


3-23 February 2008

Figure 3-5

Figure 3-6


February 2008 3-24

Figure 3-7

Figure 3-8


February 2008 3-25

Figure 3-9

Figure 3-10


February 2008 3-26

Figure 3-11

Figure 3-12


February 2008 3-27

Figure 3-13

Figure 3-14


February 2008 3-28

Figure 3-15

Possible location for biotention in The Business Park

Figure 3-16



February 2008 3-29

Figure 3-17


Figure 3-18


February 2008 3-30

Figure 3-19

Figure 3-20


February 2008 3-31

Figure 3-21


February 2008 3-32

Figure 3-22


February 2008 3-33

Figure 3-23

Figure 3-24


February 2008 3-34

Figure 3-25

Figure 3-26


February 2008 3-35

Figure 3-27

Figure 3-28


February 2008 3-36

Figure 3-29

Figure 3-30


February 2008 3-37

Figure 3-31

Figure 3-32


February 2008 3-38

Figure 3-33

Figure 3-34


February 2008 3-39

Figure 3-35

Figure 3-36


February 2008 3-40

Figure 3-37

Figure 3-38


February 2008 3-41

Figure 3-39

Figure 3-40

Airport Avenue landscaping


February 2008 3-42

Figure 3-41

Figure 3-42


February 2008 3-43

Figure 3-43

Figure 3-44


February 2008 3-44

Figure 3-45

Figure 3-46


February 2008 3-45

Figure 3-47

Figure 3-48


February 2008 3-46

Figure 3-49

Figure 3-50


February 2008 3-47

Figure 3-51

Figure 3-52


February 2008 3-48

Figure 3-53

Figure 3-54


February 2008 3-49

Figure 3-55

Grant Elementary School on Pearl Street

Figure 3-56

23rd and Pearl Street catch basin, facing west on 23

rd Street


February 2008 3-50

Figure 3-57

Pearl at 31st Street

Figure 3-58

Pearl at 31st Street


February 2008 3-51

Figure 3-59

Figure 3-60


February 2008 3-52

Figure 3-61

Figure 3-62


February 2008 3-53

Figure 3-63

Figure 3-64


February 2008 3-54

Figure 3-65

Figure 3-66


February 2008 3-55

Figure 3-67

Santa Monica College Parking Lot

Figure 3-68

Santa Monica College Parking Lot facing southwest.


February 2008 3-56

Figure 3-69

Figure 3-70


February 2008 3-57

Figure 3-71


February 2008 3-58

Figure 3-72

Proposed locations for traffic calming landscaping


February 2008 4-59

4.0 BMPs Evaluated

4.1 Stakeholder Workshop

A workshop was held on June 20, 2007 convened by the City. At the workshop, the information included in Appendix E was presented. Based on feedback from the workshop a shortlist of BMPs was chosen for further analysis. These are described in section 4.2 below.

4.2 BMP List for Further Analysis

A total of 10 BMPs was identified in this process that can be categorized into the following areas: Airport Property:

1. Airport Avenue Landscaping 2. SMC Parking Lot Underground Retention 3. Zinc Hangar Runoff Management

Residential Area:

4. Traffic Calming Landscape Modification 5. Pearl Street Rain Gardens 6. Grant Elementary School Underground Retention 7. Clover Park Underground Retention 8. Pico Boulevard Porous Pavement

Business Park:

9. Business Park Bioretention Retrofit Other:

10. Penmar Water Quality Improvement and Runoff Reuse Water quality calculations were performed based on the City of Los Angeles SUSMP (Standard Urban Stormwater Management Plan) methodology to provide design guidance on BMPs. This method determines the peak flow (QPM) or stormwater volume (VPM) that should be mitigated as a result of ¾” of rainfall. Water quality calculations are summarized in Table 4-1 below.


February 2008 4-60

Table 4-1 Water Quality Calculations Summary

Sub-area QPM [cfs] VPM [cf] WASE [cf] TMDL [cf] Drains to

21st 3.4 47,694 36,565 23,847 Penmar Pk

23rd 15.7 192,032 147,225 96,016 Penmar Pk

25th-N 31.7 355,178 272,303 177,589 Clover Pk to Rose

25th-S 28.9 340,585 261,115 170,292 Airport Ave to Rose

TOTAL 935,489 717,208 467,745

Penmar Park 3.5 29,403 22,542 14,702 To Rose

See Appendix for Water Quality Calculations.


February 2008 4-61

4.3 Worksheets and Photos—Feasibility at a Planning Scale

4.3.1 AIRPORT PROPERTY

4.3.1.1 Airport Avenue Landscaping

This proposed BMP will remove gunite along Airport Avenue and replace it with landscaping and trees. Due to the long length of the street, vegetated swales may be utilized within landscaping. Airport Avenue drains from east to west and there is an existing storm drain on Dewey Street. Targeted pollutants are sediment, oil and grease, and metals. There are no major construction constraints other than demolition, possible utility relocation, earthwork, landscaping, and drainage piping. The cost of this BMP is estimated to be roughly $440,000.

Figure 4-1

Airport Avenue Landscaping


February 2008 4-62

4.3.1.2 SMC Parking Lot Underground Retention

As shown in Figure 4-2, this proposed BMP will build an underground extended retention basin (ERB) with pretreatment (for proprietary trash, suspended solids, oils, and etc.) underneath an existing Santa Monica College parking lot adjacent to the Airport Avenue. If soil conditions allow, this EDB would have a pervious membrane to allow infiltration. This BMP would collect drainage from other parking lots to the east and possibly from Airport Avenue. Low-flow runoff should be treated via infiltration, and high-flow runoff should be bypassed to a nearby storm drain system on Dewey Street or to an airport runway storm drain system which eventually drains to the Dewey Street storm drain. Targeted pollutants are nutrients, trash and debris, oxygen demanding substances, oils and grease, bacteria and viruses, and metals. There are no major construction constraints other than demolition, installation of BMPs, earthwork, paving, and drainage piping. The cost of this BMP is estimated to be roughly $1,380,000.

Figure 4-2

SMC Parking Lot Underground Retention


February 2008 4-63

4.3.1.3 Zinc Hangar Management

As shown in Figure 4-3, this proposed BMP will build planter boxes along the sides of airport hangars to treat its roof runoff. The planter boxes should be designed to treat the low-flow runoff. High-flow runoff should overflow onto the adjacent areas as in the existing condition. Targeted pollutants are metals. There are no major construction constraints other than earthwork, landscaping, and if necessary, drainage piping. The cost of this BMP is estimated to be roughly $75,000.

Figure 4-3

Zinc Hangar Runoff Management


February 2008 4-64

4.3.2 RESIDENTIAL AREA

4.3.2.1 Traffic Calming Landscape Modification

As shown in Figure 4-4, this proposed BMP will modify existing traffic calming devices into street rain gardens. The existing landscape will be sunken into the ground to provide storage for water quality treatment. Curb cuts should be made so that the street surface flow would be directed into the rain gardens. The depth of depression for each rain garden should be determined by the water quality mitigation volume (VPM) of its tributary area. There are total of nine possible locations identified in Figure 4-4. Targeted pollutants are sediment, oil and grease, and metals. There are no major construction constraints other than earthwork, landscaping, and if necessary, drainage piping and relocation of existing utilities. The cost of this BMP (for all nine locations) is estimated to be roughly $450,000.


February 2008 4-65

Figure 4-4

Traffic Calming Landscape Modification (Yellow Highlighted Areas = Possible BMP Locations)

4.3.2.2 Pearl Street Rain Gardens

This proposed BMP will build two new street rain gardens along Pearl Street. Pearl Street is one of the major residential streets that carry relatively large amounts of surface runoff due to the lack of storm drain systems within the street. Possible BMP locations should


February 2008 4-66

be identified so that the proposed location is strategic from a drainage point of view (i.e. downstream portion of street where surface flow is most concentrated) and is acceptable in terms of traffic and safety. Targeted pollutants are sediment, oil and grease, and metals. There are no major construction constraints other than earthwork, possible utility relocation, landscaping, and if necessary, drainage piping. The cost of this BMP is estimated to be roughly $200,000.

4.3.2.3 Grant Elementary School Underground Retention

As shown in Figure 4-5, this proposed BMP will build an underground retention basin with pretreatment (for proprietary trash, suspended solids, oils, and etc.) underneath an existing playing field at Grant Elementary School. The school is located near the upstream end of the Airport Watershed. Also, there is an existing storm drain system that drains south along the eastern property of the school site. Drainage from this storm drain should be diverted to a pretreatment device before discharging into the proposed underground retention basin. Low-flow runoff should be treated via infiltration; high-flow runoff should be bypassed to the storm drain on 25th Street. Targeted pollutants are nutrients, trash and debris, oxygen demanding substances, oils and grease, bacteria and viruses, and metals. There are no major construction constraints other than demolition, earthwork, repaving, and drainage piping. School buildings may cause some site constraints when diverting drainage from the adjacent existing storm drain system. The cost of this BMP is estimated to be roughly $795,000.

Figure 4-5

Grant Elementary School Underground Retention


February 2008 4-67

4.3.2.4 Clover Park Underground Retention

As shown in Figure 4-6, this proposed BMP will build an underground retention basin (ERB) with pretreatment (for proprietary trash, suspended solids, oils, and etc.) underneath existing baseball fields at Clover Park. There is an existing storm drain system adjacent to the park on 25th Street draining from north to south. Its drainage areas include the park itself, drainage on 25th Street, and portions of The Business Park to the northeast and airport runway to the east. The existing storm drain on the 25th Street should be diverted to a pretreatment device before discharging into the proposed underground retention basin. A soils analysis is recommended to determine the soil condition and infiltration capacity of Clover Park. Additionally, storm water stored in the underground retention basin may be reused to complement the park’s irrigation demands. Targeted pollutants are nutrients, trash and debris, oxygen demanding substances, oils and grease, bacteria and viruses, and metals. There are no major construction constraints other than installation of BMPs, earthwork, possible utility relocation, storm drain connection, and drainage piping. The cost of this BMP is estimated to be roughly $2,155,000.

Figure 4-6

Clover Park Underground Retention


February 2008 4-68

4.3.2.5 Pico Boulevard Porous Pavement

This proposed BMP will repave pedestrian crossings at one or more of the intersections along Pico Boulevard with porous pavement. Along Pico Boulevard, stormwater runoff flows from east to west at the sides of the street via gutter usually. Thus, porous pavements at the pedestrian crossings would be ineffective since it would have minimal contact area with the runoff. Targeted pollutants are sediment, oils and grease, and metals. There are no major construction constraints other than paving. The cost of this BMP is estimated to be roughly $180,000.


February 2008 4-69

4.3.3 BUSINESS PARK

4.3.3.1 Business Park Bioretention Retrofit

As shown in Figure 4-7, this proposed BMP will retrofit the existing landscaping within The Business Park with bio-swales and rain gardens. These BMPs should be designed to treat the low-flow volumes based on its tributary areas. High-flow runoff can overflow onto the parking lots as in the existing condition. Targeted pollutants are sediment, oil and grease, and metals. There are no construction constraints other than demolition, earthwork, landscaping, and if necessary, drainage piping. The cost of this BMP is estimated to be roughly $1,250,000.

Figure 4-7

Business Park Bioretention Retrofit


February 2008 4-70

4.3.4 OTHER

4.3.4.1 Penmar Park Water Quality Improvement & Runoff Reuse

As shown in Figure 4-8, this proposed project will implement underground retention, infiltration, and possible reuse of storm water to address sub-regional water quality issues. This sub-regional BMP is expected to treat runoff from both the cities of Los Angeles and Santa Monica. Refer to the “Penmar Water Quality Improvement and Runoff Reuse Project” prepared by the City of Los Angeles and the City of Santa Monica, dated March 2007, for detailed project information and cost estimate.

Figure 4-8

Penmar Park Water Quality Improvement & Runoff Reuse


February 2008 6-71

4.4 Amounts and values of Avoided Potable Water Use

In the scenarios above, avoided potable water use as a result of reuse occurs within the City of Los Angeles at Penmar Golf Course. As a result, no savings in dollars to the City of Santa Monica will occur.

5.0 Next Steps

5.1 Capital Improvement Plan

Based on costs of BMPs, work with City staff to allocate costs by fiscal year.

6.0 Conclusion

The intent of this report is to identify possible BMPs that will help improve the overall storm water quality of the Airport Watershed in the City of Santa Monica. Total of ten BMPs were identified and analyzed in terms of construction constraints and costs, pollutants targeted, and site feasibility at a planning level. A detailed engineering analysis is recommended for prospective BMPs to determine design-specific information. A cost-benefit analysis should be conducted for the proposed BMPs to help determine priority for each of the BMPs. The cost-benefit analysis should take into consideration, at the least, the drainage area, capacity, and cost of the BMPs. The prioritizing of BMPs should consider, at the least, the results of the cost-benefit analysis, existing BMPs, financial and timing logistics, and the City’s needs.

It is important to note that the entire Airport Watershed is one of the tributary areas of the Penmar Water Quality Improvement and Runoff Reuse Project, which is a sub-regional storm water quality improvement project. Thus, the Penmar Project is designed to mitigate much of the Airport Watershed’s storm water runoff (VPM). However, implementation of the recommended BMPs would improve the storm water quality closer to the pollutant source. Moreover, implementation of the recommended BMPs would likely reduce the design capacity and construction cost of the Penmar Project. Therefore, additional study is recommended to analyze the impacts of proposed BMPs on the design and cost of the Penmar Project.


6-1 February 2008

APPENDIX A

Technical Memorandum


APPENDIX B Penmar Water Quality Improvement and Runoff Project


APPENDIX C

County Department of Health Services Health Standards


February 2008

APPENDIX D Recommended BMPs Design Performance


February 2008

APPENDIX E Workshop Presentation – June 20, 2007

Documents

Santa Monica Airport Watershed Management Project