| The Louisiana Oil Spill Geographic Information System
By David Gisclair, Jay Arnold, and DeWin H. Braud, Jr. When the first oil well in Louisiana was drilled in 1901, petroleum's impact on the Bayou State was incomprehensible. It is now nearly impossible to travel across land or water in Louisiana without seeing oil-related activity. Whether in the form of pumping jacks, pipelines, tankers, or production facilities, oil is everywhere. To date, approximately 209,000 wells have been drilled on land and offshore across Louisiana. About 20% of the United States' domestic oil supply is produced in Louisiana. In the last 15 years, the Louisiana Offshore Oil Port (LOOP) offloaded 3.5 billion barrels of foreign crude oil from 3350 tankers. These tankers travel daily in Louisiana's coastal waters. As well, barges traverse Louisiana rivers and other waterways transporting the world's oil.
While this black gold is crucial to Louisiana's economy, it also poses a threat to the state's environment. As we learned from the Exxon Valdez disaster in Alaska, oil spills can be both environmentally and economically disastrous. When the 1990 Oil Pollution Act (OPA 90) was passed as a direct response by our nation's government to the Exxon Valdez disaster, Louisiana had the foresight to create the Louisiana Oil Spill Coordinator's Office (LOSCO). This office is responsible for the regulation of Louisiana's oil industry to ensure our state does not meet the same fate as Alaska. In conjunction with OPA 90, Louisiana's Legislature passed ACT 740, the Louisiana Oil Spill Prevention and Response Act, to set state regulations that complement and extend OPA 90 regulations.
ACT 740 mandates the development of a statewide oil spill contingency plan. This plan will prepare Louisiana for the ever-present possibility of oil spills. Specifically, ACT 740 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 required technical data for this Environmental Baseline Inventory (EBI) must address the needs of oil spill planning, response, and natural resource damage assessment. The data also must serve as a comprehensive information base necessary to protect the interests of the state in the event of a major oil spill.
Because geographic location of physical and cultural features is extremely important for oil spill planning and response, LOSCO determined that a geographic information system (GIS) is the best method for compiling, storing, retrieving, and analyzing the data required for the EBI. To fulfill the mandate, LOSCO, 3001, Inc. (formerly Vernon F. Meyer and Associates, Inc.), and Louisiana State University (LSU) are developing the Louisiana Oil Spill Geographic Information System (LOGIS). This team is meeting the needs of the state of Louisiana with innovative and cost-efficient methods unprecedented until now. As a result, the EBI has the potential to be, according to Roland Guidry, Louisiana's Oil Spill Coordinator, "the most credible database put together for any state." Study Area
The mandated project study area is the coastal waters of Louisiana. "Coastal waters" are defined in state law R.S. 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 10,000 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.
However, since oil spills can occur throughout the state, 3001 will create new data sets and incorporate existing data sets that address the entire state where applicable. For instance, 3001 is creating USGS color infrared Digital Orthophotography Quarter Quadrangles (DOQQs) for the entire state. As well, any data sets acquired for the EBI that cover the entire state are incorporated into the project in complete form. As a result of such thorough inclusion, LOSCO and the state of Louisiana will receive a comprehensive project that not only meets the project specifications but also exceeds them. Louisiana Oil Spill Contingency Plan Map
As the first step of developing an effective system, LOSCO and LSU developed in 1995 the Louisiana Oil Spill Contingency Plan Map (LACPM) in hardcopy format and on CD-ROM. The LACPM is a composite Landsat Thematic Mapper (TM) satellite image with a spatial resolution of 30 meters (m) per pixel. The digital version has been released on CD-ROM in ArcView format together with the following additional data sets:
U.S. Geological Survey Digital Line Graph road network
Parish political boundaries
U.S. Geological Survey 1:100,000 quadrangle index
U.S. Geological Survey 1:24,000 quadrangle index
Water-related place names
Populated place names
Latitude/longitude graticule
Astronomical high tide line
The Louisiana Department of Environmental Quality (LDEQ) has recently released a new statewide image of Louisiana with improved spatial accuracy and made it available to LOSCO for the LOGIS project. Merging SPOT panchromatic data with the Landsat TM composite created this image. The merged image acquires the advantageous features of each satellite. TM imagery are multispectral - detecting reflected energy in 3 bands of the visible and 3 bands of the infrared portion of the electromagnetic spectrum. The SPOT imagery utilized for this merger is panchromatic - a black and white single band primarily spanning the green and red visible range of the spectrum. When the 2 data sets are mathematically merged, the resulting imagery has the characteristics of both original data sets; that is, it appears as a color 10 meter (m) image, acquiring the multispectral feature of the TM and the higher resolution of the SPOT. The TM data were acquired during the 1992-93 winter, and the SPOT data were acquired during the 1990-95 time period.
This project was funded by the Louisiana Department of Environmental Quality (DEQ) in cooperation with the Louisiana Department of Natural Resources and the USGS National Wetlands Research Center. The data were processed in the DEQ GIS Center Laboratory.
The LACPM and the merged SPOT-TM image are valuable data sources for statewide oil spill planning and response. They are currently being used for oil spill drills and planning. As well, oil companies and state and federal agencies find numerous applications for the LACPM image. The Louisiana Fish and Wildlife Service is using the image on a laptop for real-time mapping of vegetative salinity regimes from helicopters. The GPS location of the helicopter is mapped on the LACPM laptop image as it moves from location to location.
However, the LACPM does not provide the detailed information and spatial accuracy required to complete the mandate for the EBI demanded in ACT 740. Therefore 3001 was contracted to develop the EBI for LOSCO. Major Components of the EBI
The EBI will provide relevant information for oil spill planning, response, and natural resource damage assessment. The challenge for 3001 is this: to gather multitudes of scattered data, create multitudes of nonexistent data, organize all of it, and make it available to LOSCO twenty-four hours a day, seven days a week. Much of the information 3001 needs exists, but it is scattered across the state and in different sources. Therefore, 3001 must access the data and organize it in a form readily accessible by LOSCO. As well, 3001 will collect any required data not already in existence. The EBI will prove to be a comprehensive database, housing for the first time a vast array of information in a single location. It will, according to Guidry, "prove to be one of the most useful tools ever for Louisiana-and not just for oil."
The GIS data sets required for the LOGIS EBI fall under ten 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 of these data sets are of particular interest because of the approach the team is taking to acquire them. They are the base map layers, including Digital Orthophotography Quarter Quadrangles and feature locations; location of monitoring points, including baseline sampling and analysis; and potential oil spill locations, including pit and barge studies. Digital Orthophotography Quarter Quadrangles
3001 is producing statewide, USGS color infrared (CIR) Digital Orthophotography Quarter Quadrangles (DOQQs) as a detailed basemap to augment the TM overview map and SPOT-TM merge imagery for the EBI. 3001 is using unprecedented methods and cutting edge technology to accomplish this task. These methods and technology are saving LOSCO time and money.
The DOQQs are being created through an innovative partnering agreement with the U.S. Geological Survey (USGS). The first step upon establishing the agreement was to fly the entire state according to National Aerial Photography Program (NAPP) standards for CIR DOQQs. This is the first time DOQQs have been produced statewide by a single year's flight. To accomplish this flight during the short Louisiana flying season, 3001 contracted USGS-NAPP contractor Northwest Group to provide the statewide photography. Northwest used three pressurized twin-engine aircraft equipped with Wild RC-30 cameras, onboard flight management and airborne Global Positioning System (GPS). All photography was captured from January through February, 1998, in spite of the record El Nino weather pattern.
3001 used five GPS Continuous Operation Reference Stations (CORS) around the state for airborne GPS control. By using airborne GPS during the flight, 3001 greatly reduced the need for field survey control, which is typically established with ground-based GPS. Northwest Group flew a total of 15,000 line miles of aerial photography, including cross-strips to augment aerotriangulation. These NAPP photos were flown 20,000 feet above ground level at a scale of 1:40,000. As the next step, the USGS office in Reston, Virginia, now is reviewing the processed film.
Two additional time and money saving aspects of the DOQQ initiative are 3001's use of automated aerotriangulation and roll-feed, single-pass scanning. 3001 will use automated aerotriangulation to extend photogrammetric control. Automated aerotriangulation greatly reduces the technician time required for bridging over standard Fully Analytical Aerotriangulation (FAAT) methods. Also impressive is the scanning method used on the DOQQ project. 3001 will use its Zeiss SCAI single-pass, roll-feed scanner. It requires only a single pass for all three colors, cutting scan time by two-thirds. In addition, the scanner has the capability for roll-feed scanning, eliminating the need to feed the photographs in individual frames. Through an agreement with EROS Data Center, 3001 will scan the dodged duplicate film rolls instead of the original. This will provide a high quality image without the need for film diapositives.
3001 will use standard USGS Level II Digital Elevation Models (DEMs) in the orthorectification process. Some Level II DEMs exist; 3001 will create the others using raster-to-vector data conversion from Mylar contour separates of the standard USGS 1:24,000 quadrangle maps. CIR photography was chosen for the DOQQs to ensure the highest level of applicability for the EBI and other interests.
CIR photography, as opposed to black-and-white or standard color photography, not only greatly improves one's ability to identify the land-water interface, but it also has enhanced capabilities for soil type and wetness delineation, vegetation delineation, assessment of vegetation health and quality, and identification of cultural versus natural features. Gulf States with needs similar to Louisiana are developing projects using CIR orthophotography as well. Specifically, Texas and Florida are creating CIR digital orthophotographs for oil spill contingency planning, land use and land cover studies, environmental assessment, and GIS support. They are wise. DOQQs provide a proven method for creating high-resolution imagery with well-defined costs. Feature Location
Under the Environmental Baseline Inventory, 3001 is required to locate surface features in each LOGIS category for natural resources and oil-related facilities throughout the study area. LOSCO has identified four possibilities for data sources, ranging from existing data that is directly usable to non-existing data that must be provided through new mapping and GIS analysis. Because many GIS and mapping projects have similar data requirements, one of the main challenges is to prevent duplication of effort when locating data and assessing its usability.
To collect existing information, 3001 must first locate and incorporate the data sets. Primary criteria for all existing data include: spatial and content accuracy, age of the data set, update cycle, distribution format, and general availability.
When data does not meet this criteria, 3001 will perform new mapping for the required LOGIS layers. However, since there is so much new data to be acquired, mapping by traditional field techniques would be cost-prohibitive. Therefore, 3001's mapping plan calls for using the CIR DOQQs they are producing. Through photo interpretation, natural resources and oil-related facilities can be identified on the imagery.
Mapping features through photo interpretation using the CIR DOQQs in an all-digital environment bypasses the traditional methods of location. Traditionally, field crews mapping oil-related facilities are guided by standard topographic maps and permits. Using photo interpretation methods, CIR DOQQs are displayed on a computer screen in-house. Because of their 1m resolution, the images reveal many oil facilities to in-house interpreters. If there is a question in-house about the site, field crews are then sent to a known, pinpointed location to verify the map accuracy. This innovative method not only saves time and money, but it is also highly effective and thorough. Moreover, the creation of CIR DOQQs and their use for mapping features answers, with a single solution, LOSCO's need for high resolution imagery and surface feature location. Baseline Sampling and Analysis Study
Another major component of the EBI is the Baseline Sampling and Analysis (BSA) study. This new product will provide a means to evaluate the current petroleum hydrocarbon concentrations in Louisiana's coastal zone sediments where an oil spill could occur. Four contractors are sampling over a three-year period to provide GPS coordinates and laboratory analysis of samples taken throughout the study area. 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.
The sampling study concentrates on areas exhibiting a high probability for oil spills. LOSCO ranked areas in terms of probability as follows: Areas adjacent to Gulf shipping lanes Areas adjacent to inland shipping lanes Major crude oil pipelines at points of greatest hazard (e.g., under navigation channels, through areas subject to subsidence and areas surrounding major terminals) Areas surrounding oil fields, refineries, major crude oil tank farms and other fixed sources
ACT 740 emphasizes the importance of protecting sensitive environmental areas that require additional sampling points. The sampling frequency, number of sample points, and the number of laboratory tests required for the samples are subject to change based on the results of the initial year's sampling.
LOSCO and 3001 developed a Microsoft Access 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 monitor sampling progress by displaying the sample coordinates stored in the database as an ArcView¨ GIS theme superimposed on base map themes from the LACPM system database.
The ability to quickly display this type of geospatial information proves to be 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 and Barge Studies
Two specific studies identify oil sites that pose a threat. The purpose of the first effort, known simply as the "pit study," is to identify and locate abandoned oil production facilities and apparatus that pose a potential threat for creating an oil spill through either natural or accidental causes. In the coastal waters, erosion and other problems frequently expose oil production elements that were formerly buried or on land. These elements include oilfield waste pits, pipelines, manifold headers, and tank batteries. Additionally, the cribbing around a well may decay or fall away, leaving the well exposed. These exposed elements also are susceptible to damage by boat traffic.
In the field, contractors for LOSCO note all apparatus and pits with this potential. The positions of these features are determined with GPS. The observable data recorded 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 approximately 16,200, all cataloged in the working LOGIS database.
The purpose of the barge study is to inventory abandoned vessels and barges in Louisiana's coastal waters. The inventory locates containers of oil waste (primarily abandoned vessels) requiring immediate attention and potential containers for oil waste which could become a hazard. Such containers may hold oil or other hazardous wastes that could be released into the environment or are potential repositories for future illegal hazardous waste dumping. The inventory allows LOSCO to access various data including location of the vessel, identification of the vessel and its owner (if determinable), and a priority based on hazard potential. The inventory includes 802 vessels located in 3 zones of the project study area.
LOSCO and 3001 converted data from an existing Microsoft Access database of barge and pit locations into a standard framework for direct integration with ArcView. LOSCO and 3001 monitor progress by displaying the pit and barge coordinates stored in the database as an ArcView theme superimposed on base map themes from the existing LACPM system database. Conclusion
The completed EBI will be a tool with many applications. Distributing and maintaining such a large volume of data will become the next challenge. 3001 and LOSCO already are planning for distributing the system over the Internet. However, serving more than a terabyte of data via FTP or through a Web browser currently is not feasible. The team now is evaluating its data set priorities and researching new data compression techniques so they will be prepared when it becomes time to distribute the data.
With a broad range of data incorporated into the system, LOSCO will be able to meet all its needs from oil spill planning to response to damage assessment. Therefore, while the tankers and barges continue to carry the black gold into and out of the Bayou State, the people of Louisiana can let the good times roll. Through preparation for the worst, LOSCO is preventing it. As a result, LOSCO is protecting the best resources the state harbors: its people and its environment. About the Author:
David Gisclair presently serves as the Oil Spill Coordinator's Technical Assistant Program (TAP) Director for the State of Louisiana. For over twenty years, he has made his livelihood from Louisiana's abundant natural resources. Gisclair earned a BS in Petroleum Engineering at Louisiana State University, and a BS in Computer Science and MBA from Nicholls State University. Jay Arnold utilizing his experience in GIS, remote sensing, and GPS applications, serves as Vice President of GIS Services for 3001. He has nine years of experience in GIS application development and three years experience in GIS project management. A native of Louisiana, Arnold graduated from Louisiana State University, where he earned a BA in Geography, a BA in Journalism and an MS in Geography. DeWitt H. Braud, Jr. is employed in the Department of Geography and Anthropology at Louisiana State University . He has extensive experience in remote sensing and GIS applications comprising the entire state of Louisiana and involving numerous state and federal agencies. Back |
