David Gisclair and Jay Arnold
Using ArcView to Manage Louisiana's Oil Spill GIS
The Louisiana Oil Spill Coordinator's Office (LOSCO) is using Esri's ArcView software to manage the Louisiana Oil Spill Geographic Information System (LOGIS). LOSCO is required by a state mandate to address oil spill planning, response, and natural resource damage assessment from unauthorized discharges of oil. The mandate specifically calls for work including an abandoned barge inventory, a remnant oilfield "pit" and related features study, an environmental baseline inventory, a baseline sampling and analysis study, and a comprehensive mapping project. To assist LOSCO with the environmental baseline inventory, 3001, Inc. is developing a comprehensive information base of more than 500 gigabytes of new data and another terabyte of existing data for the information system. Other contractors, government agencies, and the oil and gas industry are assisting with information acquisition and development through all phases of the project, including the barge and pit studies, the sampling and analysis project, image processing, and training. In fact, the LOGIS system relies on the cooperation and contributions of dozens of local, state and federal agencies as well as the private sector. LOSCO is managing this 3-year, $20 million project with a one-person GIS staff. Without ArcView, data development and management would be much more challenging for LOSCO and 3001.
INTRODUCTION
The LOGIS project began in response to the Louisiana Oil Spill Prevention and Response Act (Act 740), which states that "an environmental baseline inventory shall be developed and maintained in such a manner that it will provide the coordinator with the technical data regarding the coastal waters before, during and after an unauthorized discharge of oil." The statewide plan addresses oil spill planning, response and natural resource damage assessment. It also provides for a comprehensive information base necessary to protect the interests of the state in the event of a major oil spill.
Since most of the inventory information has a spatial component, LOSCO determined that a computer based geographic information system (GIS) is the best method for compiling, storing, retrieving, and analyzing relevant oil spill data. When complete, the system will utilize remote sensing imagery, environmental baseline inventory data, and various additional vector layers and associated databases vital to contingency activities. Many of the required data sets are being compiled using Esri's ArcInfo and ArcView GIS software. The final system will be an ArcView-based application available through the Internet's World Wide Web.
LOSCO chose ArcView GIS as the information platform because ArcView provides an efficient and effective means of managing geospatial data. As contractors develop new data sets for LOGIS, LOSCO uses ArcView to review contractor performance and quality of deliverables. ArcView is also used to check existing data against accuracy standards developed by LOSCO and 3001 before implementation into the information base. The information base will consist of collected data sets, including a sampling and analysis data set, pit and barge studies, an environmental baseline inventory, and USGS Digital Orthophotography Quarter Quadrangles (DOQQ's). Since the ultimate goal of the project is an application that uses all collected data to allow LOSCO to meet its mandate (ACT 740), 3001 and LOSCO must ensure that the data brought into the LOGIS is accessible, manageable, portable, and relatively easy-to-use. ArcView guarantees that ability.
STUDY AREA
The mandated project study area is the coastal waters of Louisiana. "Coastal waters" are defined in the Louisiana Revised Statue. 30:2454(2) as "the water and bed of the Gulf of Mexico within the jurisdiction of the State of Louisiana, including the arms of the Gulf of Mexico subject to tidal influence, estuaries, and any other waters within the state if such other waters are navigated by vessels with a capacity to carry ten thousand gallons or more of oil as fuel or cargo." The major navigable waterways included in the study area are: the Mississippi River; the Atchafalaya Navigation Channel; the Red River; and the Ouachita/Black River. The coastal waters are of primary concern; however, since oil spills can occur throughout the state, LOGIS will incorporate existing data sets that address the entire state of Louisiana where applicable.
DISCUSSION
LOSCO is managing many concurrent projects as part of its overall mission. Therefore, successful management of the LOGIS project relies on efficient review of spatial data sets built by other agencies and contractors. The Environmental Baseline Inventory (EBI) being developed by 3001 incorporates the data from all LOSCO efforts into a centralized system to be accessed using ArcView to ensure efficiency and effectiveness.
Environmental Baseline Inventory
The Environmental Baseline Inventory consists of locating and incorporating existing data sets and performing new mapping for any required LOGIS layers where there are no reliable data sets. Because many existing GIS and mapping projects have similar data requirements, one of the main tasks is to acquire and evaluate existing information to prevent duplication of effort. Primary criteria for existing data include: spatial and content accuracy; age of the data set; update cycle; distribution format; and general availability. The data collected must be suitable for oil spill planning, response, and damage assessment.
The GIS data sets required for the LOGIS EBI fall under these categories:
Base Map Layers
Transportation Systems
Protected Areas
Sensitive Environments
Potential Oil Spill Locations
Ocean Currents
Historical Hurricane Tracks
Location of Monitoring Points
Remedial Action Facilities
Major and Minor Oil Spill Data
Three major data collection efforts being managed by LOSCO are highlighted below: the baseline sampling and analysis project, the pit study, and the barge study.
Baseline Sampling and Analysis
One very important data set that must be created is a sampling and analysis layer for petroleum hydrocarbon concentrations in Louisiana's coastal zone sediments. This new data set will provide a means to evaluate the current hydrocarbon concentrations where an oil spill could occur. Four contractors are sampling over a three-year period to provide Global Positioning System (GPS) coordinates and laboratory analysis of samples taken throughout the study area. The final product will provide an environmental baseline for hydrocarbon trend analysis. First year field work for the sampling component includes pinpointing monitoring points by GPS on land and in water and performing sample collection and analysis. Years two and three involve re-sampling the points established during year one.
LOSCO and 3001 developed a Microsoft Access relational database to assist field crews with their sampling. Using laptop computers, field crews can now input field data directly into a digital format, including Latitude and Longitude with corresponding UTM coordinates from the GPS. As the study progresses, each contractor's database shows the cumulative samples collected. LOSCO and 3001 are monitoring sampling progress by displaying the sample coordinates stored in the database as an ArcView theme superimposed on base map themes from the existing Louisiana Oil Spill Contingency Plan Map CD-ROM.
The sampling and analysis data set includes 1180 sample sites located in four geographic zones where each zone contractor provides samples and corresponding anlayses. LOSCO and 3001 read sample point records from the sampling and analysis database directly into ArcView. ArcView easily illustrates where attribute errors occur. These errors include incorrect coordinates, improper parish identifiers, and empty database fields. The ArcView program also maps different types of points using different colors, or maps different contractor's points using different colors or symbology.
The ability to quickly display this type of geospatial information is an invaluable asset for project management. This ability allows management to observe differences between actual and proposed sample locations, monitor sampling progress visually and evaluate projected completion for sampling operations.
Pit Study
The pit study also allows LOSCO to view data for accuracy using ArcView. The pit study identifies the remnants of former oil production sites that pose the threat of an unauthorized discharge of oil. In the coastal water areas, erosion frequently exposes oil production elements that were formerly buried or on land, including pipelines, manifold headers, and wells. Additionally, the cribbing around a well may decay or fall away, leaving the well head exposed. These exposed elements become a navigational hazard increasing the potential of an oil spill. The purpose of the pit study is to identify and locate abandoned oil production facilities and apparatus that pose a potential threat of an oil spill through either natural or accidental causes.
LOSCO contractors investigate potential oil spill sources. In the field, they note all oil production apparatus and earthen oil well and production facility pits with this potential. The positions of these features are determined with GPS. The observable data for each location includes feature type, observations on the feature, and in some cases, photographs or site plans. The total number of sites inventoried to date is 29,241, all catalogued into the working ArcView database.
Barge Study
The purpose of the barge study is to inventory abandoned vessels (primarily abandoned cargo barges) in Louisiana's coastal waters. Such vessels may hold oil-field or other hazardous wastes which can be released into the environment or provide repositories for future illegal dumping. The barge study data includes location of the vessel, identification of the vessel and its owner (if determinable), and a priority removal ranking based on hazard potential. The inventory includes 802 vessels located in three zones of the project study area. The study provides an inventory of vessels containing oil-field or other hazardous waste requiring immediate attention, an inventory of abandonded vessels which could become a hazard, and a systematic methodology for arresting the abandoned vessel threat.
LOSCO and 3001 converted an existing Microsoft Access database containing barge locations into a standard framework for direct integration with ArcView. LOSCO and 3001 display barge coordinates stored in the database as an ArcView theme superimposed on base map themes from the existing Oil Spill Contingency Plan Map CD-ROM created by LSU.
LOSCO and 3001 read records from the pit and barge databases directly into ArcView. ArcView easily illustrates where attribute errors occur. These errors include incorrect coordinates, improper parish identifiers, and empty database fields. ArcView maps different types of points using different colors or symbology.
Basemap Imagery
In an effort to compile a new state base map, LOSCO and other state agencies identified the need for a LANDSAT Thematic Mapper (TM) image mosaic. A new product was created from geo-rectified EOSAT TM data at 30-meter pixel resolution. The coordinate system is Universal Transverse Mercator (UTM), zone 15, North American Datum of 1927 (NAD 27). The LSU Department of Geography and Anthropology compiled ten TM scenes captured between November 1992 and March 1993 to provide an RGB composite map using TM bands 7,5 and 3 as the red, green, and blue input. The image has been compressed to 8-bit format and distributed in ArcView readable format via the Louisiana Oil Spill Contingency Plan Map CD-ROM.
Though the TM image is an excellent base map for regional studies, LOSCO requires imagery of a much higher resolution for contingency planning, response and damage assessment. Moreover, because inventory requirements include locating many unmapped surface features, 3001 is producing USGS-compliant, color infrared (CIR) one-meter pixel DOQQ's. 3001 will use the CIR DOQQ images to map surface features in a "heads-up" digitizing environment in ArcInfo. The images will provide spatial location for items such as oil storage facilities, oil response equipment facilities, marinas, oil production facilities and terminal facilities. This innovative mapping approach answers LOSCO's need for high resolution imagery and surface feature location with a single solution. However, the shear size of the statewide DOQQ layer renders it impractical for real-time regional or statewide display and analysis. Moreover, the DOQQs are CIR, which does not show the ground surface in its "true" coloration. For these reasons, it cannot be overemphasized how important it is to have the LANDSAT TM base map.
Flight planning for the DOQQs is managed with ArcView. An ArcView project was created to illustrate flight lines and photo frame exposures for the entire state of Louisiana. Without ArcView, it would be very difficult to keep up with the status of the flight mission. The ArcView flight indexing system has become the project tracking system for the other processes required for DOQQ production. The ArcView project will track the production and status of ground control, Digital Elevation Models (DEMs), orthorectification, and USGS submittal and acceptance of flight and DOQQ products.
Conclusion
The ultimate goal of the project is an ArcView application that uses all the data to allow LOSCO to meet its mandate (ACT 740). Therefore, it is logical for 3001 to use ArcView to manage its own development of the LOGIS. Consequently, ArcView is being used on two levels, by 3001 to develop the EBI for LOGIS and by LOSCO to manage the LOGIS.
Acknowledgements
The LOGIS system could not be developed without the cooperation and support of local, state, and federal agencies and the private sector. LOSCO would like to thank all parties involved throughout the development of all activities related to this multi-faceted project.
David Gisclair
Technical Assistance Program Director
Louisiana Oil Spill Coordinator's Office
1885 Wooddale Boulevard, 12th Floor
Baton Rouge, LA 70806
Phone: 504.922.3245
Email: tapgis@linknet.net
Jay Arnold
VP, GIS Services
3001, Inc.
3655 SW 2nd Avenue, Suite 3C
Gainesville, FL 32607
Phone: 352.379.3001
Email: jarnold@3001data.com
Website: www.3001data.com