"~ .

P;~cific OCS Region MMS OCS STUDY 2004·025

(JjiS Database Characterizing the Hardbottom Habitats

~learOCS Structures in the Pacific Region

February 2004

Authors

L.arry E. Deysher

Hay deWit

Noel Davis

Published by

u.S. Department of the Interior

lIIIinerals Management Service

I=»acific OCS Region

Camarillo

February 2004
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MMS OCS STUDY 2004-025

Table of Contents

Page

List of Figures ii

List of Tables iv

Introduction 1

Habitat Classification System 2

Table 1. Habitat Classification 2

Confidence Index Data 4

Substrate Data Sources 5

Hardbottom Substrate Shapefile - MMS~hardbottom 10

Substrate Relief 38

Video Data ; ; 42

Metadata 42

References 42

Appendix A- Training Manual. 43

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MMS OCS STUDY 2004-025

List of Figures

Page

Figure 1. Areas within 2 miles of platforms, pipelines, and power cables defining

the study region for the project. 1

Figure 2. Coverage of sonar surveys in the Santa Barbara Channel region

compared to the areas of interest around the OCS structures 6

Figure 3. Coverage of sonar surveys in the Long Beach region compared to the

area of interest around the OCS structures ; 7

Figure 4. USGS multibeam bathymetry data in the vicinity of the OCS platforms

on the San Pedro Shelf 8

F:igure 5. USGS multibeam backscatter data in the vicinity of the OCS platforms

on the San Pedro Shelf 9

Figure 6. Relationships between the Hardbottom attribute database and the

Habitat, Confidence, Map Reference, and Report Reference databases..... 10

Figure 7. Cultural Resources Constraints map in the vicinity of Platform Irene

overlaid with MMS platform sites, MMS HARDBOTT2 data, the coverage

area for the MBARI multibeam sonar survey, and the location of an area of

hardbottom identified from the MBARI survey 12

Figure 8. Area of hardbottom substrate at the head of a submarine canyon just

to the west of Platform Irene 13

Figure 9. Area of hardbottom substrate at the head of a submarine canyon just

to the west of Platform Irene as shown on the MBARI backscatter data. ..14

Figure 10. Post-construction side scan mosaic (Pelagos 1987) showing potential

hardbottom feature (circled) to the west of Platform Irene 15

Figure 11. Comparison of the sidescan mosaic detailed in Figure 10 with the

Cultural Resources Constraints map detailed in Figure 7 15

Figure 12. MBARI multibeam backscatter data in the region of Platform Hidalgo.

...................................................................................................................................16

Figure 13. MBARI hillshaded bathymetry data overlaid with the final hardbottom

substrate polygons 17

Figure 14. A composite map of the side-scan sonar surveys conducted by

Meridian Ocean Systems in 1987 18

Figure 15. Comparison of the hardbottom substrate areas with the defined

hardbottom substrate areas on a "Cultural Resources Constraints" map

produced for a pipeline project between the proposed Shamrock Platform

and Platform Hermosa 19

Figure 16. MBARI multibeam backscatter imagery .in the region of Platforms

Harvest and Hermosa 20

Figure 17. Survey coverage for the stUdy area along the pipeline route from

Platform Hermosa to shore 21

Figure 18. Hard substrate regions delineated along the Platform Hermosa

pipeline 21

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MMS oes STUDY 2004-025

Figure 19. Boundaries of the large-scale maps used to identify the hardbottom

substrates 22

Figure 20. An example of one of the large-scale substrate maps used to identify

each of the hardbottom substrate polygons 22

Figure 21. Hillshaded relief map created from the MBARI multibeam bathymetry

data in the vicinity of Substrate Feature 253 : 23

Figure 22. The backscatter data from the MBARI multibeam sonar survey in the

vicinity of SF 253 24

Figure 23. Dames & Moore map (1982) of surficial features in the vicinity of SF

253 24

Figure 24. Hard substrate areas delineated in the Vicinity of Platforms Heritage,

Harmony, Hondo, and along the associated pipeline and cable routes........25

Figure 26. Portion of the Surficial Features map from the John E. Chance &

Associates survey conducted in 1991 27

Figure 27. Backscatter image from the MBARI multibeam sonar study in the

region of Platform Heritage 28

Figure 28. Backscatter image shown in Figure 27 overlaid with the hard

substrate features 28

Figure 29. Hillshaded bathymetry data from the MBARI survey overlaid with the

substrate features polygons 29

Figure 30. Hillshaded bathymetry map from the MBARI survey in the vicinity of

Platform Harmony 30

Figure 31. Backscatter map from the MBARI survey in the vicinity of Platform

Harmony 30

Figure 32. Backscatter map from the MBARI survey in the vicinity of the shelf

break along the pipeline route from Platform Hondo to shore 31

Figure 33. Hillshaded bathymetry map from the MBARI survey in the vicinity of

the shelf break along the pipeline route from Platform Hondo to shore........32

Figure 34. Hard substrate features delineated in the nearshore region of the

Santa Ynez Unit and at the shelf break along the pipeline/cable routes from

Platform Hondo to shore 33

Figure 35. Hard substrate features overlaid on a recent habitat map from the

SYU inshore area : 34

Figure 36. Hard substrate features overlaid on a 1991 habitat map for the region

of the Capitan control area 34

Figure 37. Hill shaded bathymetry map in the vicinity of the San Gabriel

submarine canyon and the Shell Beta Unit platforms: 35

Figure 38. Coverage areas of the three USGS multibeam sonar surveys

conducted in the Los Angeles region in 1996, 1998, and 1999 36

Figure 39. Multibeam backscatter data from the USGS surveys 36

Figure 40. Hardbottom habitats characterized from the USGSmultibeam data by

Dr. Gary Greene 37

Figure 41. Overview of the hardbottom substrate features delineated for the San

Pedro / Long Beach area , "'37

Figure 42. Hardbottom habitats near the Rincon pier area. The boundaries of

the sonar survey coverage are shown in green 38

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MMS OCS STUDY 2004-025

Figure 43. Substrate relief map in the vicinity of Platform Hidalgo overlaid with

the CAMP study sites arid the hardbottom substrate polygons created for the

project. 40

Figure 44. Substrate relief map for the San Pedro shelf and San Gabriel Canyon

regions 41

List of Tables

Page

Table 1. Habitat Classification 2

Table 2. Biological Categories ; 3

Table 3. Information included in the Confidence Index database 5

IV
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MMS Des STUDY 2004-025

GIS Database Characterizing the Hardbottom Habitats

Near OCS Structures in the Pacific Region

Introduction

Various geophysical survey maps and biological reports spanning the time period

from 1977 to 2002 were used to identify the locations and habitat characteristics

of hardbottom features within 2 miles of DeS structures in southern California.

The areas covered by the project are shown in Figure 1. The purpose of the

project was to develop a GIS database that can be used to determine the

potential for damage to sensitive habitats during decommissioning activities for

the DeS structures. The database also provides a spatial synthesis of the

available data to provide a view of gaps in survey covera~e.

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Figure 1. Areas within 2 miles of platforms, pipelines, and power cables

defining the study region for the project.

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MMS OCS STUDY 2004-025

Habitat Classification System

The first phase of the project was to develop a habit classification scheme that

would provide a standardized method for summarizing the available biological

information for the hardbottom features. The habitat classification system

developed for the project was modeled after the scheme for deep seafloor

habitats used by Gary Greene and the Center for HabitatStudies at Moss

Landing Marine Laboratories. This classification system has a hierarchical

design that permits varying levels of detail depending on the available data

sources and interests of the project (Greene et ai, 1999). The classification

scheme we developed has the same hierarchy as the Greene system along with

various modifiers that increase the usefulness of the system for delineating the

biological communities in the vicinity the OCS structures. Table 1 shows the

variables that were used to define the habitat types for the hardbottom

substrates. The first eight of these variables are found in the attribute table

associated with the shapefile (MMS_hardbottom.shp) that describes the

hardbottom substrates. The remaining variables are found in the Habitat table

(MMS_HabitacTable. xIs) that is associated with all the features for which

biological data is available. The biological categories used in the community

modifier are found in Table 2.

Table 1. Habitat Classification

Item Name Values for Item Notes

Feature Number Sequential number Unique index number

OCS Structure Name Platform or pipeline within 2 miles

Area Santa Maria Basin

Santa Barbara Channel

San Pedro Shelf

Depth of Feature Range in meters (MLLWj

OCS Block

Latitude

Longitude

Size of Feature Area

MegaHabitat Intertidal

Shallow Subtidal· 0 to 30 m

Outer Shelf - 30 to 150 m

Upper Slope - 151 to 500 m

Intermediate Slope - 501 to 1,000 m

MesolMacrohabitat Reef

Pinnacle

Boulder Field

Slump

Debris Field

Canvon

Tar Mound

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MMS OCS STUDY 2004-025

Substratum Subclass Mixed Sediment

Gravel/Pebbles

Cobble

Boulder

Bedrock

Relief Subclass Low < 1 m vertical

High > 1 m vertical

Slope Modifier Vertical Wall (60 - 9Cf)

Steeply sloping (30 - 6rt)

Sloping (2 - 3rt)

Flat (0 - 1°)

Overhang (>90°)

Community Modifier Dominant Macrobiota Defined in Table 2

Sediment Cover Modifier None

Thin veneer <0.5 em

Moderate > 0.5 em < 2 em

Thick > 2 em

Reference Author/date of source Source(s) ofdata

Reference Index Number related to source/tracking

database

Table 2. Biological Categories'

Intertidal

• Surfgrass community (P!?J!!ospadix spp). is slow to recover from disturbance and provides

habitat for several species of marine invertebrates and fishes.)

• Black abalone (regionally rare and found in the intertidal rocky habitat)

• Barnacle community (mid to upper intertidal)

• Mussel I algal turf community (mid to lower intertidal)

• Laminarian community (low intertidal to shallow subtidal)

Shallow Subtidal (to 30 m)

• Kelp bed (Macrorystis, an important commercial and habitat-creating alga. Other algae

[i.e. Egregia, Pterygophora, and (ystoseira], invertebrates, and fish are associated with this

community.)

• Abalone (The white abalone, Ha!iotis sorensoni is a federally-listed species and other

species of Ha!iotis are considered regionally rare by California State resource agencies)

• Lobster (Panu!irus is an important commercial invertebrate associated with rocky features

within this depth range).

• Rockfish (Some species of the genus 5ebastes have been recently listed and most of the

members of this genus are comniercially~important and have "depleted" stocks.)

• General community (This category includes two subcategories, neither of which are

associated with kelp. Subcategory (a) includes algal and invertebrate taxa that are

sensitive to sedimentation ~.e. gorgonians and perennial alg~e]; subcategory (b) includes

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MMS OCS STUDY 2004-025

the seditnent-tolerant algal and invertebrate taxa [cup corals Astrangia, Coenoryathus,

Ba/anophy//ia].

Outer Shelf (31 to 150 m)

• Rockfish (See Rockfish above.)

• Large sponges/gorgonians (These taxa are slow-growing, long-lived, and sensitive to

increased sedimentation. Both are usually associated with higher-relief features within

the these water depths.)

• A//oporaILophe/ia (Although not formally listed, these colonial, erect corals are slowgrowing and have limited larval distribution. They are also considered to be relatively

"rare" within the study area and have been species of concern during previously

completed environmental assessments.)

• General community CVarying with water depth and vertical relief, this category includes

Metridium, Staurocafyptus, Pachastre//a, F/orometra, Gorgonocepha/us, and Pararyathus.)

Upper Slope (151 to 500 m)

See Outer Shelf. The same general categories are proposed for this depth range and while

the general community organisms will vary slightly, in general, the sensitivity of those

communities are similar to those found in the Outer Shelf depth range.

Intermediate Slope (501 to 1,000 m)

See Outer Shelf. The same general categories are proposed forthis depth range and while

the general community organisms will vary slightly, in general, the sensitivity of those

communities are similar to those found in the Outer Shelf depth ,range.

Confidence Index Data

In addition to the development of the habitat classification during the first phase

of the project, a habitat sensitivity index was developed to provide a rapid way to

show the relative importance of a hardbottom substrate feature based on

considerations of 1) the scarcity of like sites, 2) the value as habitat for species of

scientific or commercial interest, 3) potential sensitivity to disturbances such as

turbidity, and 4) the potential for recovery from disturbance. After a review of the

factors comprising the proposed sensitivity index, the TPEC decided that the

data relevant to making decisions on sensitivity would be contained in the

proposed GIS data layers. They concluded that it would be more important to

have some measure of the degree of confidence that could be ascribed to the

data defining each hardbottom feature. The sensitivity of a feature could be

described much more confidently for features that had detailed ROV video or

manned submersible surveys than for those where only a sonar surveyor a few

photo samples were available. They suggested that a database with information

of the number and types of surveys for each hardbottom 'feature would be the

best way to generate a confidence index when determining a sensitivity level for

a feature. The elements found in the Confidence Index database are listed in

Table 3. This database is associated with each hardbottom feature of the final

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MMS OCS STUDY 2004-025

GIS database for which biological survey data is available. The biological survey

data were obtained from the reports in the Report Reference database

(MMS_ReporCReference.x/s). A listing of the Confidence database is found in

the Excel file MMS_Confidence_Table. xis.

Table 3. Information included in the Confidence Index Database

Number of Surveys

Survey type and date

Sub-bottom profile

Sidescan sonar

Multibeam sonar

Groundtruth Information +/- and date

Type of Groundtruth survey

ROV +/- mesotech or equivalent

Video BW or Color

Still photos BW, Color, 3D

Qualitative index of coverage on feature

Lowered video camera - BW or Color

Lowered still camera

BW, Color, 3D

Quantification of photo +/-

Survey design - Random, haphazard, systematic

Manned Submersible

Video - BW, Color, 3D

Still photos - BW, Color, 3D

Qualitative index of survey extent

SCUBA surveys

Video - BW,Color, 3D

Still photos - BW, Color, 3D, photoquadrats

Qualitative index of survey extent

Substrate Data Sources

Various map sources were used in compiling the final hardbottom substrate GIS

database. These map sources including original sidescan mosaics, substrate

maps produced for MMS geohazards and biological studies, a sidescan survey of

the western Santa Barbara Channel produced by MBARlin 1998, a series of

USGS surve~ on the San Pedro shelf, a recent Fugro West survey conducted

for a power cable project in the San Ynez Unit, and historical kelp surveys

compiled by the Channel Island National Marine Sanctuary.

The area covered by each of the source maps is summarized in a series of

footprint polygon shapefiles. The area covered by the MBARI multibeambackscatter survey is described in the shapefile MBARCfootprint.shp, the 1998

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MMS OCS STUDY 2004-025

and 1999 USGS multibeam/backscatter surveys are described in the shapefile

USGS_SanPedro_footprint.shp, and the various sidescan composites, paper

maps and AutoCad files are summarized in MMS_scan~footprint.shp. A

complete list of the maps used in the study is found in the Excel file

MMS~Map_reference.xls.

The coverage of the surveys in the Santa Barbara Channel can be seen in Figure

2. The MBARI survey covered most of the western channel. Various older sidescan surveys and two recent USGS side-scan surveys augment the coverage of

the MBARI survey in the nearshore areas and near Platform Irene. The new

USGS data, however, was not available for this study.

The San Pedro area has been well covered by USGS multibeam surveys

conducted in 1996, 1998 and 1999. Sidescan surveys conducted during the

1978 EIR for the development of the OCS Beta Unit extend the coverage into the

Long Beach harbor area and nearshore in the Huntington Beach area (Figure 3).

Figure 2. Coverage of sonar surveys in the Santa Barbara Channel region

compared to the areas of interest around the OCS structures.

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MMS OCS STUDY 2004-025

Legend

C::r:2'lllli,<.< ~ur~;itit>Ji'd,~i:8~1iU';j~

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Figure 3. Coverage of sonar surveys in the Long Beach region compared

to the area of interest around the DCS structures.

The USGS multibeam sonar survey for the Los Angeles offshore region

consisted of three separate surveys conducted in 1996, 1998, and 1999. A

complete description of the surveys can be found at

http://geopubs.wr.usgs.gov/open-file/of02-162/index.html. The surveys of most

interest to the MMS project are those conducted on the San Pedro shelf in 1998

and 1999. The bathymetric data in the vicinity of the DCS platforms are shown in

a hillshaded format in Figure 4 and the backscatter data are shown in Figure 5.

Figure 4 shows the relationship of the platforms to the nearby San Gabriel

Canyon on the shelf break. Figure 5 shows large regions of high backscatter to

the west of the platforms and smaller areas along the northern pipeline route.

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MMS DeS STUDY 2004-025

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2 ,'i) ":: 4· .--

!Min~rals Milil:l~g~me)1f~.ervi6:'::

. San:p:e.droSh~lf Stll.~Y. ::~r~,a:· -f-:---l-C.~:lhj-.-----.I'

-'. ~iIJllfyjl..:!003.

.USGS: Multibeam-Bathymetne Survey

Figure 4. USGS multibeam bathymetry data in the vicinity of the DeS

platforms on the San Pedro Shelf.

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MMS OCS STUDY 2004-025

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2 i.

Minerall$Managem~rfft :SerVice

$an·P~droShe.lf ·Study, Ate~ ~--'1-.~-:"':".i!-, -=---1 , ,'." F~b~~.2llOO"

U$GS:!BackscaUerSurw~ :

Figure 5. USGS multibeam backscatter data in the vicinity of the OCS

platforms on the San Pedro Shelf.

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MMS OCS STUDY 2004-025

Hardbottom Substrate Shapefile • MMS_hardbottom

The cornerstone of the hardbottom feature database is the polygon shapefile

describing the location, shape, and size of each of the hardbottom features. This

shapefile has a total of 647 polygons within 2 miles of the offshore platforms,

pipelines, and power cables. The attribute table for the shapefile contains a

feature ID number, a reference to the primary source map used to describe the

feature, the major secondary map used to corroborate the ·feature shape and

location, the number of maps that covered the region of this feature, the number

of these maps that show the feature, the average depth ofthe feature, the area

of the feature, the latitude and longitude of the centroid of the feature, and an

item indicating whether biological habitat data is available for the feature. We

have also added the ratio of the number of maps showing the designated feature

to the total number of maps covering the area of the feature. A ratio of 1

indicates a prominent feature seen in all the surveys and a low ratio could

indicate either a feature smaller than the minimum mapping unit used for the

surveyor a hardbottom feature that is covered by a layer of sediment. The

feature ID number is the primary index that links the feature with the Habitat and

Confidence databases as shown in Figure 6.

oes HardbotlOOl Database Relationships

Conid enc e T~ ble (Fe a1unl)

MMS M~p Reienlnc e (M~p Nu mb er)

Figure 6. Relationships between the Hardbottom attribute database and

the Habitat, Confidence, Map Reference, and Report Reference

databases.

Each hardbottom feature is also associated with a listing of the primary map

sources that were used for plotting the size, shape, and position of the polygon in

the hardbottom feature shapefile. There were a total of 66 map sources used in

the project, of which 50 were paper maps that were scanned into digital format.

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MMS OCS STUDY 2004-025

The remaining sources were digital files including ESRI GRID files for the

multibeam surveys by MBARI and USGS, AutoCAD files for recent surveys

conducted by Fugro, and a shapefile of the historical locations of kelp canopies

compiled by CA Fish and Game and the Channel Islands National Marine

Sanctuary. The Map_Number variable in the MMS_Map....Reference.xls data file

can be associated with the SourceMap and Second_Map variables in the

Hardbottom feature data table.

Hardbottom Substrate Areas in the vicinity of Platforrm Irene

A total of 4 older sonar maps and the recent MBARI multibeam sonar data were

used for delineating the hardbottom substrate areas within the 2 mile area of

interest around Platform Irene and the associated pipeline. Figure 7 shows a

portion of a "Cultural Resources Constraints" map produced by McClelland

Engineers in 1984. This map has been overlaid with the platform site derived

from the MMS GIS database and a substrate polygon from the MMS

HARDBOTT2 shapefile. The HARDBOTT2 polygons appear to summarize areas

of high relief substrate areas throughout the OCS area. We have identified the

sources of these data in about 50% of the cases. The source of the

HARDBOTT2 polygon for this region has not been identified, but the area

identified by the polygon coincides with an area defined as a "zone of seafloor

disturbance attributed to oil exploration activity" in the Cultural Resources

Constraints map. Only a portion of the polygon, however, is covered by this

map. There is also an area of "seafloor scarring from removal of casing or well

head by explosive charge" within the area of the HARDBOTT2 polygon. Areas

of "rock outcrop" are listed in the legend of cultural resources map, but none are

identified in this immediate area. It appears, therefore, that the HARDBOTT2

polygon in this region is delineating an area of disturbed soft bottom sediments.

The primary hardbottom substrate in this area was identified from the MBARI

backscatter data as an area of high backscatter at the head of a small submarine

canyon (Figures 8 and 9). The habitat data for this site come from Dames and

Moore reports in 1984.

A potential area of hard substrate near Platform Irene is shown on a postconstruction side scan sonar mosaic conducted by Pelagos in 1987. The sonar

data show a well defined feature 35 m in diameter located approximately 350 m

west of Platform Irene (Figure 10). The Cultural Resources Constraints map

identifies a magnetic anomaly at the location of this sidescan feature (Figure 11).

The only other areas of hard substrate associated with Platform Irene are two

small areas in the shallow subtidal where the pipeline from the platform comes

ashore. An area on the northern edge of the 2-mile buffer zone was identified

from the historical kelp distribution database developed by the Channel Island

National Marine Sanctuary. Another area just north of the pipeline was identified

by sonar studies conducted by McClelland Engineers in 1983. There is no

evidence of kelp populations growing on this later feature.

11
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MMS OCS STUDY 2004..025

;.t~""a~Ji..---.." es,~~ .... :¢ Hp~eottomsa.es

Q;'.: Pta1:fotm'"srt~s; _. . -".... '. if ~:,

D2..mlle:9uffet

r~q~8:~f~1~:

Figure 7. Cultural Resources Constraints map in the vicinity of Platform

Irene overlaid with MMS platform sites, MMS HARDBOTT2 data, the

coverage area for the MBARI multibeam sonar survey, and the location of

an area of hardbottom identified from the MBARI survey.

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MMS OCS STUDY 2004-025

Figure 8. Area of hardbottom substrate at the head of a submarine canyon just

to the west of Platform Irene. The Cultural Resources Constraints map detailed

in Figure 7 is overlaid onto hillshaded bathymetry data from the MBARI survey.

The hillshading for this map is set with the sun positioned in the northwest corner

of the map creating shadows on the south facing slopes. The hardbottom

substrate in the area is located on the small hillock just to the west of the purple

cross.

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MMS Des STUDY 2004-025

Figure 9. Area of hardbottom substrate at the head of a submarine canyon just

to the west of Platform Irene as shown on the MBARI backscatter data. The

hardbottom substrates in the area can be identified as the lighter gray areas of

higher backscatter return.

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MMS OCS STUDY 2004-025

,,<,-,o,j,"---1-------1-------I...".~:;iI'::..,.'+

;,~..j---+-------'l+.I

.~~,~'.--:'l7:

Figure 10. Post-construction side scan mosaic (Pelagos 1987) showing potential

hardbottom feature (circled) to the west of Platform Irene.

Figure 11. Comparison of the sidescan mosaic detailed in Figure 10 with the

Cultural Resources Constraints map detailed in Figure 7. The black diamonds

on the Cultural Resources map indicate magnetic residuals attributed to oil

exploration activity. '

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MMS Des STUDY 2004-025

Hardbottom Substrate Areas for Platform Hidalgo

Hardbottom substrates in the vicinity of Platform Hidalgo were identified using 4 sidescan sonar maps and the recent MBARI multibeam sonar survey. A general overview

of the area is shown in Figure 12, which also shows the substrate polygons overlaid

onto the MBARI backscatter data. Figure 13 shows the hardbottom substrate polygons

overlaid onto the MBARI hillshaded bathymetry. This figure also shows the footprirt of

the side-sonar surveys used in delineating the hardbottom substrate areas. It appears

that there are many small valleys and depressions in this area that do not contain any

hard substrate. However, outside the footprint of the older high-resolution side-scan

surveys, only larger substrate areas are able to be identified with the MBARI multibeam

data.

Figure 12. MBARI multibeam backscatter data in the region of Platform Hidalgo.

The lighter areas are areas of higher backscatter return due to the presence of

hard substrate. The right-hand figure shows the defined hardbottom substrates

for this region overlain on the backscatter data.

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MMS OCS STUDY 2004-025

Figure 13. MBARI hillshaded bathymetry data overlaid with the final hardbottom

substrate polygons. The light yellow area indicates the total survey footprint of

the older side-scan sonar data. The lighting is coming from the upper left hand

corner of the image which shades valleys on the northwest sides. Elevated

areas are brighter on the northwest side.

The general method for delineating the hardbottom substrate polygons was to digitize

the shapes based on the older high-resolution side-scan sonar maps, but then position

the polygons based on the substrate features on the MBARI backscatter and

bathymetry data. Figure 14 shows the final substrate polygons overlaid onto the

Meridian Ocean Systems sonar maps created in 1987. The shifts required to register

the substrate polygons with the MBARI data ranged from 0 to 150 meters. Figure 15

shows the substrate polygons overlaid onto a portion of a Cultural Resources

Constraints map produced for a pipeline project between the proposed Shamrock

Platform and Platform Hermosa. The positions of the final substrate polygons aligned

fairly well with the hard bottom substrates defined from this map, but the shapes were

quite different.

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MMS oes STUDY 2004-025

~~~ j~~~~ ,......-----.;.;.+~-----------'-:''+'';:.;;',._-_......._----,..,

I

f

Figure 14. A composite map of the side-scan sonar surveys conducted by

Meridian Ocean Systems in 1987. The shapes of the substrate area were

generated from these maps, but then positioned based on the MBARI

backscatter data.

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MMS OCS STUDY 2004-025

...s~­

·i.iiil~,,,··.---+21lr--------

.: "

1.:otI:4*,~''''

l1U"'4Jit'w:·

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Figure 15. Comparison of the hardbottom substrate areas with the defined

hardbottom substrate areas on a "Cultural Resources Constraints" map produced

for a pipeline project between the proposed Shamrock Platform and Platform

Hermosa. This map was only used a comparison for the other data sources.

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MMS OCS STUDY 2004-025

Hardbottom Substrate Areas for Platforms Harvest and Hermosa

Hardbottom substrates in the vicinity of Platforms Harvest and Hermosa have been

identified using 4 side-scan sonar map interpretations, the original side-scan mosaics

from the 1988 Meridian Ocean Systems Survey, and the recent MBARI multibeam

sonar survey. A general overview of the area is provided in Figure 16, which shows the

substrate polygons overla id onto the MBARI backscatter data.

Like the generation of the polygons in the vicinity of Platform Hidalgo, the shapes of the

hard bottom features were based on the interpretation of the Meridian Ocean Systems

high-resolution side-scan sonar maps produced in 1988, but the final positions of the

polygons determined by the MBARI backscatter data. The amount of offset between

the surveys varied from area to area, but was generally on the order of 25 meters in the

vicinity of Platform Hermosa.

A B

Figure 16. MBARI multibeam backscatter imagery in the region of Platforms

Harvest and Hermosa. The lighter areas indicate higher backscatter return due

to the presence of hard substrate. Figure 1 B shows the defined hardbottom

substrates for the region o-..erlaid on the backscatter data.

Hardbottom Substrate Areas for Platform Hermosa Pipeline Route

Hardbottom substrates along the pipeline route from Platform Hermosa to shore were

identified using 7 side-scan sonar map interpretations and the recent MBARI multibeam

sonar survey. An overview of the survey coverage in this area is provided in Figure 17,

which shows the area to the north of the pipeline that was not been covered by any of

the surveys.

20
MMS oes STUDY 2004-025

Figure 17. Survey coverage for the study area along the pipeline route from

Platform H~rmosa to shore.

An overview of the substrates created for this region is shown in Figure 18. A series of

larger-scale maps were produced on which the Feature Number for each substrate

polygon identified. These maps were used by Ray deWit to match the substrate areas

With descriptions in the survey reports and with the video data. The boundaries of these

maps are shown in Figure 19 and an example map is shown in Figure 20.

'I~

Figure 18. Hard substrate regions delineated along the Platform Hermosa

pipeline.

21
1\1I1\1I~ {)r.~ ~TllnV ?004...025

Figure 19. Boundaries of the large-scale maps used to identify the hardbottom

substrates.

+ +

1mb~".·

... :+

,.,.n "0

+ + .'"t ...11~."."

'~

Figure 20. An example of one of the large-scale substrate maps used to identify

each of the hardbottom substrate polygons.

22
MMS Des STUDY 2004-025

There were a few areas where it was difficult to definitively identify some of the bottom

features. The area just south of Substrate Feature (SF) 253 in Figure 20, for example,

had a series of elevated areas that were very obvious in the MBARI bathymetry maps

(Figure 21), but did not appear as distinct features in the backscatter data (Figure 22).

This region was just south of the area covered by the 1982 Dames and Moore survey

(Figure 23) that defined a portion of SF 253 as "Tar covered seafloor" and SF 244 as

"Exposed rock with local relief greater than approximately 2 feet". The backscatter

return for SF 244 in Figure 22 is much brighter than that for SF 253 and appears to

confirm the harder rock in this area.

Figure 21. Hillshaded relief map created from the MBARI multibeam bathymetry

data in the vicinity of Substrate Feature 253. The hardbottom features defined in

the Hardbottom database are overlaid onto the sonar data.

23
~~•.-. II'

:>4-025

.,.~ri.

+

·t~

Map'19 ,

4-- ·;'"tt"n

Figure 22. The backscatter data from the MBARI multibeam sonar survey in the

vicinity of SF 253.

',:-.1 ,z.').. ·0

.Jr.ft' 1:+ }- + + :"-i~~

P~t~' ,,-',

'!J'

.' i.A

I: '.f3i ,~ Ni1'Kl :~

;.,~. ~.

j..,.: la',,)"';" ... .La- 'ffl,'

Figure 23. Dames & Moore map (1982) of surficial features in the vicinity of SF

253.

24
MMS OCS STUDY 2004-025

Hardbottom Substrate Areas for Platforms Heritage, Harmony, and Hondo

An overview of the substrates delineated in this region is shown in Figure 24. Each of

the substrate polygons is tagged with a unique identifier that links it with the habitat

characteristics in the GIS database. The blocks in Figure 24 indicate the extents of

larger-scale maps that were produced for Ray deWit.

~.

+

+

+

,l'._

:'~.

. +:

+

+

'I-

+

+

+

+

+..

+'

-+

O~.' $,••' ,~ ,~ T

"'~~'~'

'~', 1~'

Figure 24. Hard substrate areas delineated in the vicinity of Platforms Heritage,

Harmony, Hondo, and along the associated pipeline and cable routes.

Sonar surveys in the vicinity of Platform Heritage consisted of three side-scan sonar

surveys and the MBARI multibeam survey. The three side-scan surveys included a

survey by John E. Chance Associates in 1991, a survey by Pelagos in 1993, and a

2002 survey by Fugro West. There were some major differences between the surveys

with regard to seafloor features. This may be related to the fact that the map from the

1993 Pelagos survey did not specify a hard substrate class, but rather listed only

"scars", "depressions", "seafloor textural variation" and miscellaneous "sonar targets".

Each feature on the Pelagos map has an identification number that is linked to a table in

the associated report. The descriptions in the table, however, did not provide much

additional information.

25
MMS OCS STUDY 2004-025

Figure 25 shows some of the differences between surveys that were encountered in this

area. The hard substrate areas currently in the database (red polygons) are shown

overlain on a portion ·of the 1993 Pelagos survey map in the v,icinity of Platform

Heritage. The green lines indicate the extent of the 2002 Fugro survey and the solid

green polygons are the hard substrate areas derived from the 2002 Fugro data. It is

evident from this map that there are many more substrate features in the 1993 survey

than those described as hard bottom in the 2002 survey. In addition, a survey

conducted by John E. Chance &Associates in 1991 shows very little hard substrate

within the area surveyed at this time (Figure 26). The only "rock outcrop" found in this

survey map is located approximately 0.5 km to the ENE of Platform Heritage. We have

taken a conservative approach in defining all of these substrate features as potential

hard bottom. This approach is supported by the results of the MBARI multibeam survey

that shows quite a bit of substrate differentiation in this region as shown in the

backscatter image in Figure 27. The region of Substrate Feature (SF) 310, which was

classified as a rock outcrop in the 1991 John E. Chance survey described above,

appears to have a backscatter value that is similar to many of the other substrate

features in the region (Figure 28).

Figure 25. Substrate features (red polygons) in the vicinity of Platform Heritage overlaid

onto the 1993 Pelagos survey map. The hard substrate areas defined in the 2002

Fugro survey (solid green polygons) and the extent of this survey (green lines) are also

overlaid onto this map.

26
j~~"

I,

MMS OCS STUDY 2004-025

The sizes and locations of some of the features were changed in order to better fit the

locations of features on the MBARI maps. For example, the long N-S trending polygons

that were derived frolTl the features on the west side of Figure 25 were shifted to better

match with the canyon edges shown in the MBARI hillshaded bathymetry in Figure 29.

+.. Il·"~"' -.. ~:

,-, ~,.:". "

Figure 26. Portion of the Surficial Features map from the John E. Chance &

Associates survey conducted in 1991. The extent of the survey is shown by the

blue lines. The only large rock outcrop shown by this survey is indicated by the

hatched lines at the northern boundary of the survey at SF 310. The majority of

the other features indicated on this map are anchor scars.

27
~-025

Figure 27. Backscatter image from the MBARI multibeam sonar study in the

region of Platform Heritage. The areas of brighter backscatter return are areas of

potentially harder substrate.

Figure 28. Backscatter image shown in Figure 27 overlaid with the hard

substrate features.

28
'I

1! ~\ ,~~.

MMS OCS STUDY 2004-025

Figure 29. Hillshaded bathymetry data from the MBARI survey overlaid with the

substrate features polygons.

There were fewer substrate features in the vicinity of Platform Harmony (Figure 30) and

the general topography in the area was much less complex than that in the vicinity of

Platform Heritage. The green lines on Figure 30 indicate the extent of the 2002 Fugro

survey conducted for the power cable replacement project. There was only one small

hard bottom feature indicated in this survey. This outcrop is indicated by the small

green polygon apprOXimately 1.6 km to the WNW of Platform Harmony. Figure 31 is the

backscatter data from the MBARI survey overlaid with the substrate features derived

from the 1993 Pelagos survey. As discussed previously, this survey did not have a

specific "hard bottom" category, but only showed "seafloor textural variation". Some of

the smaller features from this survey could be artifacts of the drilling operations, but

many of the larger features from this survey correspond with areas of higher backscatter

from the MBARI survey.

29
14-025

Figure 30. Hillshaded bathymetry map from the MBARI survey in the vicinity of

Platform Harmony. The green lines indicate the extent of the 2002 Fugro survey.

The small green polygon is the only hard substrate area found in this survey.

Figure 31. Backscatter map from the MBARI survey in the vicinity of Platform

Harmony. The green lines indicate the extent of the 2002 Fugro survey. The red

polygons are the substrate features delineated for the area.

30
----,--......"""'"-------------~~-------~------------

MMS OCS STUDY 2004-025

No hard bottom features were described in any of the surveys in the vicinity of Platform

Hondo. However, there was an extensive set of substrate features at the shelf break

along the pipeline route from Platform Hondo to shore. Hard bottom features in this

area were well described in the 2002 Fugro data, and by bright backscatter features in

the MBARI data (Figure 32). Hard bottom features in this area were also derived from

the 1990 Meridian Ocean Systems "Offshore Cables Pre-Manufacturing Survey". The

1990 survey showed more "bedrock outcrops" than those shown in the 2002 survey. .

There were also large areas of "scattered rock" in the 1990 survey that in many cases

corresponded to smaller patches of hard substrate from the 2002 survey. In these

cases only the 2002 substrate areas were delineated in the hard bottom database.

Figure 32. Backscatter map from the MBARI survey in the vicinity of the shelf

break along the pipeline route from Platform Hondo to shore. The green lines

indicate the extent of the 2002 Fugro survey. The red polygons outline the

substrate features delineated for the area, and the green filled polygons are

those specifically derived from the FugrC? survey.

31
~'

:1: 't~"'. ,'.'.

MMS Des STUDY 2004-025

The inshore boundary of the MBARI survey, unfortunately, was at the shelf break and

we don't have any multibeam data for the inshore portion of the pipeline route. The

topography of this region as well as the extent of the 2-mile study area for this study is

shown in Figure 33.

Figure 33. Hillshaded bathymetry map from the MBARI survey in the vicinity of

the shelf break along the pipeline route from Platform Hondo to shore. As in

Figure 32, the green lines indicate the extent of the 2002 Fugro survey, the red

polygons outline the substrate features delineated for the area and the green

filled polygons are those specifically derived from the Fugro survey. The light

blue area indicates the 2-mile study area around the platforms and pipeline /

cable routes in this area.

Hard bottom Substrate Features for the inshore area of the Santa Ynez Unit

and the Shelf Break along the SYU Pipeline.

A review of the substrate areas for the nearshore areas of the Santa Ynez Unit showed

that the hardbottom features delineated in surveys conducted in the late 1980's differed

significantly from recent substrate surveys. Ray deWit provided maps from the recent

inshore surveys and from additional surveys along the pipeline route at the shelf break.

32
,..

MMS OCS STUDY 2004-025

An overview of the final substrate features delineated in the SYU region is shown in

Figure 34. The blocks in Figure 34 indicate the extents of larger-scale maps that were

produced for Ray deWit for use in matching the substrate areas with descriptions in the

survey reports and with the video data. Figure 35 shows the hard substrate polygons

overlain on the most recent habitat map (Pirelli Jacobson, 2003) of the SYU nearshore

area in the region where the pipelines and power cables come ashore. The hard

substrate boundaries on the eastern portion of this area Were derived from a habitat

map (Figure 36) developed for the Capitan Marine Terminal Abandonment project.

:·'O'!(.,O·."6'"1""', '~2'. ;:r.·" !. "';"~k .,;.. , --."..

, ...~!r'~~~:

";"

A......--...-..y-----J~~~~..:·

+

Figure 34. Hard substrate features delineated in the nearshore region of the

Santa Ynez Unit and at the shelf break along the pipeiine/cable routes from

Platform Hondo to shore.

33
_,

J

',1' " : '.. 25

Figure 35. Hard substrate features overlaid on a recent habitat map from the

SYU inshore area. Dark gray areas are rock outcrops and lighter gray areas are

coarse sediment/gravel.

.-f

iT

100;.

Figure 36. Hard substrate features overlaid on a 1991 habitat map for the region

of the Capitan control area. The dark gray areas on this map indicate the anchor

preclusion zones that were defined by areas of surficial kelp (hatched areas) and

the bedrock exposures and ridges in the area.

34
..------------------------------~~

MMS OCS STUDY 2004-025

Hard bottom Substrate Features for the San Pedro Shelf

The Shell Beta Unit platforms occur along the shelf break in the vicinity of the San

Gabriel submarine canyon (Figure 37). Sidescan sonar studies for this region and

along the pipeline routes from the platforms to Long Beach harbor were conducted for

the 1978 EIR/EA conducted for the Beta Units. More recently, multibeam/backscatter

sonar surveys were conducted by the USGS in 1998 and 1999 (Figure 38). The USGS

backscatter data (Figure 39) was used by Dr. Gary Greene of the Moss Landing Marine

Lab to characterize the benthic habitats in this region. A summary of the hard bottom

habitats delineated in Dr. Greene's study is shown in Figure 40. In addition to the hard

substrates feature found along the shelf break and in the San Gabriel Canyon, there is a

large area of low relief reef on the shelf between the platforms and the entrance to Los

Angeles harbor. This area once harbored a large kelp bed and was referred to as

Horseshoe Kelp/Dago Bank. This area is still a popular areafor sportfishing and the

shallower reefs harbor populations of the kelp, Laminaria far/owii., The Bolsa Chica

artificial reef constructed by the CA Fish & Game is a large area of hard substrate just

west of Platform Eva. There are also an extensive series of low relief reefs inshore of

Platforms Eva and Emmy. An overview of the final substrate features delineated on the

San Pedro shelf region is shown in Figure 41 .

,+- + + ~.~

'1r -

+ + ~,~I

Figure 37. Hill shaded bathymetry map in the vicinity of the San Gabriel

submarine canyon and the Shell Beta Unit platforms. The bathymetry data were

produced by the USGS surveys in 1998 and 1999.

35
...._-------------------------------------

Ii";

il",1

MMS oes STUDY 2004-025

Figure 38. Coverage areas of the three USGS multibeam sonar surveys

conducted in the Los Angeles region in 1996, 1998, and 1999.

'1 1"

00,$1 .2 ),;:..',8' '8;,'

'~i<m'

.~

Figure 39. Multibeam backscatter data from the USGS surveys. The areas of

brighter backscatter return are generally hard bottom, but gravel substrates and

subsurface features can also produce a stronger backscatter return.

36
,........ 'J'"- .','

,..

Ii, ;I'~t~ ri;~"

:1

. lit""

",tM.. '_" . .", ! -t' _" ;~

!M\.;ML,Habltatpl1a,-"ctert~n.lIon·:

,118M I9tA'(;nl Ihob/lol.·

'lIIia;d11dl "'~~'

~i;:;·:~:=~~~.;,~.;.~·

• H"".~·~b rMtOo.n

.!·~~.Md:fa~~~~·~~~ "

+

I~

25

Figure 40. Hardbottom habitats characterized from the USGS multibeam data by

Dr. Gary Greene.

:+

,~

+ I

""""'I

Figure 41. Overview of the hardbottom substrate features delineated for the San

Pedro I Long Beach area.

37
j MMS OCS STUDY 2004-025

Hard bottom Substrate Features for the Carpinteria nearshore area

We located information for the location of hardbottom features near the Rincon pier from

a side scan survey that Fugro conducted as part of the Mobil Sea Cliff Pier

abandonment project. The substrates delineated from this survey are shown in Figure

42 where they are overlaid on the NOAA navigation chart for the area. The other

hardbottom features shown in this area were defined from a kelp canopy database that

was developed by the California department of Fish & Game and the Channel Islands

National Marine Sanctuary.

. hr,wil··

.'.:.... t~~ ~'~~~ .

II~ .

Figure 42. Hardbottom habitats near the Rincon pier area. The boundaries of

the sonar survey coverage are shown in green. The hardbottom features outside

of the sonar mapping area were derived from the CA Fish & Game kelp maps

(1980 -1989).

Substrate Relief

One of the objectives of the habitat classification was to define the relief characteristics

of the hardbottom features. The video surveys provide relief information for only a small

fraction of the hardbottom features found in the OCS region. Even for features that are

covered by video or photographic data, relief can usually only be defined definitively for

a relatively small area of the feature.

38
MMS OCS STUDY 2004-025

In order to better define the geological relief for broader regions of the study area, we

used an ArcView 3.3 extension that was developed by Jenness (2003) to quantify

surface complexity. This surface complexity or rugosity algorithm uses an elevation grid

to calculate the ratio of a surface area for each cell and its eight neighbors to the planar

area for this same region. The algorithm results in ratios near 1 for flat, smooth locations

and higher values in areas with more complexity and higher relief. For the MBARI

bathymetry data, which has a horizontal resolution of 10m, the planar surface each of

the grid cells would have an area of exactly 100 m2

. This area increases as the

elevation difference between the adjacent cells increases and the grid cells tilt and

enla rge. The algorithm used a grid area of 101 m2 as the cutoff to define a relief of at

least 1 meter between adjacent grid cells. The USGS surveys in the San Pedro area,

which had a horizontal resolution of 15 m, used a threshold value of 257 to define a

vertical relief of 1 m for this dataset.

Figure 43 shows the resulting geological relief map for the project study area around

Platform Hidalgo. The geological relief datasets were produced as raster geotiff files

having values ofonly 0 and 1, with 1 representing cells with relief greater than 1 meter.

The high relief cells have been coded as red in this figure. The relief data are overlaid

onto the hardbottom substrate polygons defined for the project and the locations of the

CAMP study sites. The substrate polygon at CAMP site PH-F, for example, has only a

small amount of high relief based on the rugosity analysis. The compares well with the

CAMP site description (low relief) and the biological relief description in the Habitat table

compiled by Ray deWit (10% high/90% low). The substrate polygon as CAMP site PHE, however, shows a fair amount of high geological relief, but is defined as a low relief

habitat area in the CAMP study and the in the Habitat notes.

The high relief areas in the San Pedro region occur primarily along the shelf break and

on the edges of the San Gabriel submarine canyon (Figure 44). The areas of

hardbottom in the region of the historicalllHorseshoe Kelp" and the shallow features just

inshore of Platforms Eva and Emmy have all been described as low lying reefs by all

the SCUBA surveys conducted in the region.

39
MMS OCS STUDY 2004-025

/\.

W

N'

,.

:'4:. '.

",'".".

"'~

Figure 43. Substrate relief map in the vicinity of Platform Hidalgo overlaid with

the CAMP study sites and the hardbottom substrate polygons created for the

project. The red areas define relief greater than 1 m. The light grey area

indicates the 2 mile study boundary for the project. The CAMP study site PH-U

is outside the study area for this project.

40
MMS DCS STUDY 2004-025

," y,rlli'tl" '" - , ...

:5

-/-

+

-/-

+.

-/-

-/-

-/-

-/-

+

,'I1li'F'D:'fI :, " Er!(lll,V1 11~r~.w· ;I'r f!f.I "!'1l[1YI

,,:+;: '}I-: + +~ !' v"I1Iui

.... ,\'

'1"'ll:rrrrTIJ

Figure 44. Substrate relief map for the San Pedro shelf and San Gabriel Canyon

regions. The red areas define relief greater than 1 m. The light grey area

indicates the 2 mile study boundary for the project and the green polygons are

the hardbottom substrates defined for the project.

41
il

, ~,. MMS OCS STUDY 2004..025

Video Data

The video data were selected by Ray DeWit based on video quality and positional

accuracy sufficient to identify a particular feature. The analog· video tapes were then

converted into digital format by Videobilia Labs in Concord, CA. A MPEG2 format was

used to produce the highest video quality with the minimum file size. We limited the

length of each video segment to approximately 20 to 30 seconds to keep the file size of

the digital files within reasonable limits. The video was converted into MPEG2 files that

are linked to the hard bottom features by means of a line shapefile (ROV_ Tracks.shp)

showing the approximate location of the video transects. There are 29 video segments

included in the database with a total file size of 191 MS. The files are located in the

Media\ROV_Video subdirectory.

The ROV_Tracks shapefile contains a link between the transect line and the MPEG2 file

for the feature that is activated with the Hyperlink tool in ArcMap. The video is activated

by positioning the hyperlink tool over the transect line and left clicking when the file

name for the video segment appears. A MPEG2 viewer must be present on the

computer for this feature to operate. Most current versions ofvideo players, including

Windows Media Player, will play MPEG2 format video.

Metadata

The metadata files provide a description of the primary spatial databases and define

their various attributes. The metadata files are FGDC compliant and they have been

produced in two different formats. The first is an XML file that can be viewed directly

within ArcCatalog. We have also produced an HTML format that can be viewed within

any web browser. These two formats were produced in order to make the metadata as

transportable and widely available as possible. The HTML format of the metadata files

can be found in the Metadata subdirectory. The XML format file is associated with the

other elements of the shapefile in the directory containing the shapefile.

References

Greene, H.G., M.M. Yoklavich, R.M. Starr, V.M. O'Connel, W.W. Wakefield, D.E.

Sullivan, J.E. McRea Jr., and G.M. Cailliet. 1999. A classification scheme for

deep seafloor habitats. Oceanologica Acta. 22(6): 663,.678.

42
MMS Des STUDY 2004-025

Appendix A . Training Manual

43
MMS DCS STUDY 2004-025

Scope

• Primary Spatial Databases

• Data Sources

• Hard Bottom Habitat Information

• Confidence Information

• Video Data

• Metadata

Primary Spatial Databases

ArcMap Table of Contents

The Display tab provides a listing of the primary spatial databases. These

databases are either ESRI shapefiles or raster geotiffs. The data tables are

found under the Source tab. The format of the Table of Contents is managed by

the map document file named MMS_Central.mxd. Data layers at the top of the

list are displayed on top of lower layers. Point shapefiles, su;h as the Platforms

group layer, and line shapefiles are displayed on top of the polygon layers.

EI €J MMS - 0(5 Hard Bottom

[±] Platforms

l±l Pipelines

l±l ROV_Tracks

[±] 0 Map Footprints

[±] Shoreline

l±l 0 Relief (High >1m)

EI MMS_hardbottom

Habitat

_No

.Yes

[±] Study Boundary (2 mi.)

l±l Santa 'Inez· Scan Maps

[±] 0 San Pedro - Scan Maps

[±] 0 SantaMaria Basin· Scan Maps

[±] San Pedro USGS

l±l 0 MBARI_Backscatter (Map25)

[±] 0 MBARI_Hilishade

'x

~f

i

L.............

~~'=Di=s~p='aif::Y':!::IS=O=\,jr=ce=I .....·......:..-...:..........;...-..:..-.....Jt...J

Figure 1. ArcMAP Table of Contents for the DCS Hard Bottom Database

Trammg Session - Charactenzafton of Hardbottom Habitats Near oes Structures 1
MMS DCS STUDY 2004-025

MMS_HardbottorTl

This polygon shapefile shows the location of all the hardbottom features

identified in the study and it is the keystone data file for the DCS Hardbottom

database. The data fields include:

• FID - this is an internal 10 number used by ArcMap

• Shape - polygon for this database

• Id - The Feature Number, which is unique for each substrate feature and

provides the linkage to the Habitat and Confidence tables

• SOURCEMAP -Identifies the primary map used for the location and shape

of the feature

• SECOND_MAP - Identifies any secondary map that was used to modify the

location or shape of the feature. A few features were based on more than

two maps, but only the primary and secondary maps are listed.

• TOTAL=MAPS - The total number of maps that covet the area occupied by

the feature.

• F_MAPS - The total number of maps that show the feature

• P_MAPPED - The ratio of maps showing the feature to the total number of

maps of the area. This can be used as quick meaSure of the prominence of

a feature.

• AVG_DEPTH - The average depth of the feature (meters below MLLW)

• HABITAT - Indicator of whether direct observations have been made of this

feature to characterize the biological habitat.

• X=CENTROID - Longitude of the center of the feature

• Y CENTROID - Latitude of the center of the feature

• AREA - area of the feature in m2

• MMS_BLOC - lease block number

The displayed data field is set to the Habitat variable and it shows whether

biological data is available for the features. This shapefile is directly linked to the

Habitat and Confidence data tables. The attribute table for this shapefile and the

related Habitat and Confidence tables are available through the use of the

Identify tool.

Map Footprints

This is group layer that contains three polygon shapefiles that describe the area

covered by the various survey maps. MMS_scan_footprint shows the effective

coverage of each of the sidescan survey maps that were converted into raster

geotiff format. MBARI=footprint shows the coverage of the MBARI multibeam

survey and USGS_SanPedro_footprint shows the coverage of the USGS

multibeam surveys in the San Pedro area. The default setting for these

databases is as unfilled polygons. This mode is most effective when identifying

the map coverage in the region of specific features. Filled polygons work best for

identifying gaps in survey coverage at broader scales. The data fields include:

• Id - Map number which links to the Map Reference data table

• Region - General area covered by the map

fralmng SessIOn - Characlenzabofl of Hardbottom Habttats Near oCS Structures 2
MMS DCS STUDY 2004-025

Relief

This is another group layer containing two geotiff files that were developed from

the bathymetry data of the MBARI and USGS multibeam surveys. The depth

grids from these surveys were used to create rugosity databases that were then

converted to geotiffs showing areas with relief over 1 m. The rugosity analysis

calculated the ratio between the surface area and the planar area for each cell in

the depth grid based on the elevation differences between the cell and each of its

eight neighbors. Flat areas have rugosity ratios near 1, while high relief areas

exhibit higher rugosity values. Areas of relief greater than 1 m were defined by

rugosity ratios greater than 101 in the MBARI dataset and greater than 257 in the

USGS dataset for the San Pedro region. The differences in the thresholds for

the rugosity ratios resulted from the different cell sizes in the two surveys. The

MBARI survey had a resolution of 10 meters and the USGS survey had a lower

resolution of 16 meters. Thegeotiff files have only values of 0 and 1, with 1

representing cells with relief greater than 1 meter. These cells have been coded

as red in the map document.

Study Boundary

This is the two-mile buffer around all the DCS platforms and pipelines. The

attribute table for this shapefile identifies the DCS feature from which the buffer

area was generated and the MMS shapefile used as the base for the buffer. This

file is best used as filled polygons without an outline and with a moderate degree

of transparency so that the underlying features can be seen.

Data Sources

Map References

There are three primary classes of maps that were used in this project. The first

is the set of side-scan composites that were produced as part of the geophysical,

biological, or cultural resource surveys that were conducted in the vicinity of the

DCS structures. These were available primarily as paper maps, but some

AutoCAD files were also available. The second set is the multibeam backscatter

surveys that were conducted by MBARI in the Santa Barbara Channel and by

USGS in the San Pedro area. The final set contain various special studies such

as the historical kelp canopy maps compiled by the Channel Islands National

Marine Sanctuary and the artificial reef maps produced by CA Fish and Game.

All the maps used in identifying the hard bottom features are listed in the Excel

file named MMS~Map-,eference.xls. This Excel file has been converted to an

Access database so that it could be linked with the Map footprint shapefiles.

The original scanned maps have been converted to geotiffs and are stored as

group layers based on region. The Santa Maria Basin layer contains 23 maps,

the Santa Ynez layer has 24 maps, and the San Pedro layer has 3. Viewing the

maps requires expanding the group layer, turning on the maps of interest, and

then turning on the group layer. Only the first activated map in the list will be

Trammg SessIon - Charaetenzatlon 01 Haraboftom Habitats Near OCS Structures 3
i~' I!'

!I .__ MMS oes STUDY 2004-025

visible. Some maps have a transparent background that permits better viewing

of various maps series. The backgrounds overlap in these series and prevent

viewing of data on neighboring maps. The map backgrounds can be changed by

right clicking on the selected map, selecting (left click) properties, and then

selecting "Display Background Value" of 1 and selecting ;'No color" in the fill

option. The legends are sometimes easier to read with a white background. The

best way to view the entire map, includ ing the legend, is to right click on the

selected map and then select "200m to layer". The legend can then be enlarged

with the zoom tool.

The data layers produced from the MBARI multibeam surveys are found in the

MBARLBackscatter and MBARLHillshade group layers. The backscatter maps

show the intensity of returns from the bottom. Higher intensity returns, indicated

by brighter areas on the maps, are usually hard bottom or gravel type substrate.

The hillshaded maps were produced from the girded bathymetry and show a 3D

rendition of the region. The "sun position" in these maps is to the northwest so

that hills are bright on the northwest sides and valleys are bright on the southeast

sides. The individual maps within the group layers were created at three different

resolutions. The lowest resolution ("a" series) covers the entire survey area in

one map. The intermediate resolution maps cover the survey area in 2 sections

("b" and "c" series), and the highest resolution maps cover the area in 6 sections

("d" through "i"). These maps have been made scale dependent so that the

optimum resolution map is shown at the selected scale. The scale dependency

can be turned off by right clicking on the selected layer, selecting Properties,

selecting the General tab, and selecting the "Show layer at all scales" button.

The entire series of maps is considered to be "Map 25".

The data from the USGS multibeam surveys are found in the San Pedro USGS

group layer. These surveys were conducted in 1996, 1998; and 1999. The

areas covered by these three surveys are shown in Figure 2. The Habitat layer

is an interpretation of the 1996 and 1998 data done by Dr. Gary Greene of the

Moss Landing Marine Lab as part of the Santa MonicaBay Mapping Project

sponsored by the Sa nta Monica Bay Restoration Project. The Hillshade maps

were produced from a composite of all three surveys and the Backscatter maps

were produced from each of the individual surveys.

Trammg SessIon - CharactenzatlOn of Haidbotfom HabItats Near OCS Structures

Figure 2. Areas covered by the

three USGS multibeam surveys

conducted in 1996, 1998, and

1999.

4
r:-ii,

MMS OCS STUDY 2004-025

Habitat Data

The habitat data were compiled by Ray DeWit from the references listed in

MMS_ReporLReference.xls This MS Excel file is found in the Tables subdirectory

of the MMS_Central database. Only features that have been directly observed

with ROV, submersible, or SCUBA have habitat data and they are identified by a

value of "Yes" in the Habitat field of the MMS_Hardbottom shapefile..

The relationships between the MMS_hardbottom attribute table and the other

data tables are shown in Figure 3. The data in the Habitat and Confidence tables

are directly linked with each of the hardbottom features in the Hardbottom

shapefile. The SourceMap and Second~Map data are associated with the Map

Reference table through the Map_Number. In a similar fashion, the Report

Reference table is associated with the hardbottom features through the

Reference Index number. These later two data tables must be queried

separately in either the MS Access table found under the "Source" tab in the

Table of Contents or in the Excel file found in the Tables subdirectory. The Excel

file provides easier formatting and printing of the data.

The Map Reference data is directly linked with Map Footprints shapefile that

provides a spatial index of the coverage of the various map sources.

OCS Hardbottml Database RelationShiPs

Contd enc e Ta ble (Fe a1Ure)

MMS Map Re1erence (Map Number)

Figure 3. Structure of the OCS Hardbottom data tables.

The Habitat Table is accessed from the MMS_hardbottom shapefile by

activating the Identify tool, and left clicking on the polygon of interest to bring up

the attribute table for this shapefile. MMS_hardbottom has been set as the

default layer in the layer list of the Identify Results window. However, if the Map

footprints shapefile is activated or other polygon data have been added to the

Trammg Session· Charaetenzatlon of HaidboHom Habitats Near OCS structures 5
MMS OCS STUDY 2004-025

Table of Contents then MMS_hardbottom will need to be selected in the layers

menu of the Identify Results window. The links to the Habitat and Confidence

tables are revealed by left clicking the plus sign next to "Yes". Access the

Habitat table by left clicking on the plus sign next to the Habitat table listing and

then left clicking the "-1" under the table listing. The data fields for the Habitat

table are based on the Habitat Classification defined in Phase I of the project and

include:

• Feature - Feature number in MMS_hardbottom shapefile

• OCS - Nearest OCS structure

• Area - Santa Maria Basin (SMB), Santa Barbara Channel (SBC), Santa

Ynez Unit (SYU), and San Pedro (SP)

• Mega .. MegaHabitat

• MesoMacro - Identified Meso or Macro Habitat

• Substrate - dominant substrate types

• Relief - relief described in cited reference

• Slope - general slope of substrate in the feature

• Community - characteristic biological community

• Sediment - sediment cover on hard substrate, if any

• Reference - references used to characterize the feature

• ReClndex - Reference numbers from the Report Reference table

(MMS_Reporl_Reference.xlfl

Confidence Data

The confidence data table provides information on the number and types of

surveys conducted on each of the listed features. The confidence data is queried

with the Identify tool from the MMS_hardbottom shapefile in the same manner

as the Habitat data described above. The listing for the Confidence table is

expanded by left clicking on the plus sign next the Confidence table name. The

data table is then displayed by left clicking on the "-1" under the Confidence

table. The data fields for the Confidence table include:

• Feature - Feature number

• GT_Dates - ground truth dates

• GT_Types - type of ground truth survey

• TransecClength_m .. transect length in meters

Video Data

The video data were selected by Ray DeWit based on video quality and

positional accuracy sufficient to identify a particular feature. We limited the

length of each video segment to approximately 20 to 30 seconds to keep the file

size of the digital files within reasonable limits. The video was converted into

MPEG2 format and linked to the hard bottom features by means of a line

shapefile (ROV....Tracks) showing the approximate location of the video

transects. There are 29 video segments included in the database with a total file

size of 191 MB. The files are located in the Media\ROV_Video subdirectory.

Trammg Session - Oharactenzatlon otHaidbottom RabHats Near OOS Structures 6
MMS OCS STUDY 2004-025

The ROV_Tracks shapefile contains a link between the transect line and the

MPEG2 file for the feature that is activated with the Hyperlink tool. The tool is

activated by positioning it over the transect line and left clicking when the file

name for the video segment appears. A MPEG2 viewer must be present on the

computer for this feature to operate. Most current versions of video players,

including Windows Media Player, will play MPEG2 format video.

Metadata

The metadata files provide a description of the primary spatial databases and

define their various attributes. The metadata files are FGDC compliant and they

have been produced in two different formats. The first is an XML file that can be

viewed directly within ArcCatalog. We have also produced an HTML format that

can be viewed within any web browser. These formats were produced in order to

make the metadata as transportable and widely available as possible. The

HTML metadata files are found in the Metadata subdirectory. The XML format

file is associ§ited with the other elements of the shapefile in the directory

containing the shapefile.

1rammg SessIOn - Charaetenzafton 01 Hardboftom Habttats Near OCS structures 7