GIS for Coastal Zone Management - Chapter 20

CHAPTER TWENTY Developing an Environmental Oil Spill Sensitivity Atlas for the West Greenland Coastal Zone Anders Mosbech, David Boertmann, Louise Grøndahl, Frants von Platen, Søren S. Nielsen, Niels Nielsen, Morten Rasch, and Hans Kapel 20.1 INTRODUCTION Marine oil spill sensitivity mapping has become widespread. The purpose is to provide oil spill response planners and responders with tools to identify resources at risk, establish protection priorities and identify appropriate response and clean-up strategies. GIS is an important tool in the development of oil spill sensitivity maps and can also be used for presentation. Several different principles for information integration have been used in different countries (Anker-Nilssen, 1994; Dickens et al., 1990; Hall et al., 1997; Nansingh & Jurawan, 1999; Moe et al., 2000). An environmental oil spill sensitivity atlas was produced as part of the preparations for exploratory drilling off the West Coast of Greenland (Mosbech et al., 2000). We have adapted a Canadian sensitivity index system integrating physical, biological and human-use information and combined it with elements from a Norwegian sensitivity mapping system. The Atlas covers the West coast of Greenland between 62° N and 68° N latitude. Although the area under study stretches only 700 km from north to south it encompasses approximately 18,000 km of coastline. It is the most populated area in Greenland with about 35,000 inhabitants living in 4 towns and 6 settlements. It is extremely important for fisheries and it is ecologically highly important for a number of seabird and marine mammal species. The Atlas is a multidisciplinary GIS project integrating many kinds of scientific data and local knowledge (traditional ecological knowledge). Although studies on geomorphology and coastal spawning areas were initiated for the project it was a major challenge to compile and get the most out of the existing data from many sources. This paper will outline and discuss how the data was integrated, the principles used to identify and prioritise the sensitive areas, the final Atlas product ,and the dialogue during the community consultation. © 2005 by CRC Press LLC 20.2 METHODS 20.2.1 The Atlas The following elements are included in the Atlas xcoast types, xoceanography, ice and climate, xbiological resources (fish, birds etc.), xfishing and hunting, xselected areas (e.g. seabird breeding colonies), xarchaeological sites, xlogistics and oil spill response methods. The Atlas covers the coastline in the scale 1: 250 000 and the offshore area in the scale of 1:3.5 million. In a PDF-version 34 maps cover the coastline and one set of maps shows index values for coastal sensitivity and symbols for the elements of classification (see map and legend example plates 20.1a and 20.1b and colour inserts following page 164). Another set of maps show coast types, logistics, and proposed methods of oil spill response for each area (see legend and map example plates 20.2a and 20.2.b, see colour inserts). Although a limited number of printed copies of the Atlas have been produced, the main version is published on CD. Since the target group of this atlas is not necessarily familiar with GIS, it was decided to distribute the final product in a form that is simple and quick to use and with an easy-to-use interface. The atlas with all text, maps, tables, and images is distributed on CD and on the Internet as a number of linked PDF-documents, which can be read with the free Acrobat Reader application. This allows a large amount of background information to be included as hypertext and at the same time to have a succinct and operational document. Furthermore, on the CD all geographic data is available for users to pan, zoom and print seamless maps with the free GIS-viewer ArcExplorer. The Atlas was developed with an ESRI ArcView project and an MS Access database. This database software was chosen because many of the existing data and institutional databases employ MS Access. Spatial information on the model parameters is stored in ArcView whereas all model parameter attribute values are in the Access database. Index calculations are performed with Visual Basic for Applications in the database. An important component of the Atlas is a sensitivity ranking system, which is used to calculate an index value describing the relative sensitivity of coastal and offshore areas. The sensitivity index value is calculated based on information on resource use (human use), biological occurrences, and physical environment. The sensitivity index system is based on a Canadian system used in Lancaster Sound (Dickins et al., 1990) and modified to the west Greenland fauna and other specific requirements of the Greenland study area. As a supplement to the Canadian ranking system, a number of smaller areas have been selected for priority in case of an oil spill. The selection of these areas is based on the principles from a Norwegian system (Anker-Nilssen, 1994), which gives priority to oil spill-sensitive areas for the purposes of oil spill contingency planning. While the © 2005 by CRC Press LLC Canadian index system covers the entire coast in 50-km units, and thus gives a general overview of the sensitivity, the Selected Areas system uses actual borders and thus pinpoints the sensitive areas and leaves the rest unclassified. 20.2.2 The Sensitivity Index Calculation The shoreline zone in the study area has been divided into 279 shoreline areas, each consisting of approximately 50 km of shoreline or, in the case of archipelagos, groups of islands and skerries having roughly 50 km shoreline. The offshore zone in the study area has been divided into 12 offshore areas (including 1 major fjord). The boundaries of the offshore areas are based on bathymetry and ice conditions during the winter. The importance of resource use and the abundance of a number of biological occurrences in each of the 279-shoreline and 12 offshore areas were rated on a scale from 0 to 5 by using a number of subindices. Site-specific significant habitats are indicated on each shoreline segment. For example, such sites include important bird colonies and terrestrial haul-out for harbour seals. Photos of the coastal setting for about 50 bird colonies have been included and can be accessed from links. As a part of the project, classification of the coastline geomorphology has been conducted from aerial photographs, e.g. the occurrence of rocky shores and beaches. An index value (oil residence index) of the self-cleaning ability of the coast after an oil spill has been calculated based on this classification in combination with shoreline exposure to waves and ice. For example, oil on a rocky coast exposed to wave action will be cleaned faster than oil on a beach in a protected lagoon. An oil spill sensitivity index value has been calculated for each of the 279 shoreline and 12 offshore areas based on: i) the abundance and sensitivity of selected species (or species groups); ii) resource use (human use), mainly fishing and hunting; iii) the potential oil residency on the shoreline (Oil Residency Index) based mainly on wave exposure, substrate and slope of coast; iv) the presence of towns, settlements and archaeological sites (for shorelines). The sensitivity index value for each of the 279-shoreline areas and 12 offshore areas is given. All areas are ranked as extreme, high, moderate or low sensitivity areas and a corresponding colour code has been used. The detailed index value calculations for each shoreline and offshore area can be accessed by hyperlinks. With the settings we used, the average contributions to the final sensitivity values for the shoreline areas are: biological occurrences 49%, resource (human) use 20%, oil residence index 14%, archaeological sites 12%, communities 4% and special status areas (Ramsar sites) 1%. However, this is a simplification since the oil residence index value is a factor in the calculation of the value for biological occurrences, and thus also has an indirect influence on the sensitivity values. 20.2.3 The Selected Areas © 2005 by CRC Press LLC To supplement the rather general mapping of shoreline sensitivity using the 50-km long shoreline areas, a number of small sensitive localities have been pinpointed as priority areas. A total of about 80 areas along the coast and within fjords have been selected as priority areas in the case of an oil spill situation. The basis for their selection is, compared to the coastline in general, that they are: i) of high value either environmentally or for resource use; ii) sensitive to oil spills; and iii) of a size and form that may allow effective protection in an oil spill situation with a manageable amount of manpower and equipment. The last criterion is important because it elucidates the rather limited possibilities to protect the coastline during a large oil spill and shows that tough prioritising is necessary. 20.2.4 Example of Indexing and Data Integration: Seabird Colonies The major part of the biological information incorporated in the Atlas derives from databases maintained by NERI and the Greenland Institute of Natural Resources. As far as possible automatic selection and integration routines were developed to link these institutional databases and the Atlas database. One of the databases is a file on all seabird breeding colonies known in Greenland, with information on the birds, the sites and all survey results from the sites (Boertmann et al., 1996). A selection from the database was used in the Atlas. This selection was based upon the geographical range between 62q and 68q N and on the most comprehensive surveys, as many colonies have been surveyed several times. However, inferior colonies have been omitted and criteria for inclusion are listed in Table 20.1. Most colonies have a mixed species assemblage and the total number of colonies (with different geographical location) selected is 158. The seabird colony data is used to produce a relative seabird abundance input value to the Seabird Oil Vulnerability Index scoring system which is integrated into the overall Shoreline Sensitivity Index. The seabird oil vulnerability index component takes into account the sensitivity to oil spills of the bird species both on an individual level and on a population level, as far as possible based on scientifically derived information on the characteristics of each species (Anker-Nilssen, 1987, Mosbech, 2000). These sensitivities are dependent on the behaviour and ecology of the birds, but also the distance to neighbouring colonies, which is a measure of the ability to re-colonise a colony. Moreover they take into account the status of the breeding population within the region, whether they are decreasing, increasing or stable, and finally their international conservation status (Mosbech et al., 1996). 20.2.4.1 Comments on some of the criteria The breeding population of common eider in West Greenland has decreased seriously for a century, and within the Atlas region large and dense colonies have disappeared. Large breeding populations are mainly found dispersed in extensive © 2005 by CRC Press LLC archipelagos. To exclude sites with a few scattered nesting eiders the criterion for inclusion is t 5 birds. As gulls are only moderately sensitive to oil spills, only the largest colonies are included. Black-legged kittiwake colonies with less than 50 pairs are excluded as they tend to be less stable over time. Arctic terns usually breed in dense colonies on low islands. The population in West Greenland is generally decreasing. Small colonies of less than 30 pairs are excluded. Terns are moderately sensitive to oil spills, but colonies situated on low islands are very sensitive to disturbance e.g. from oil spill response activities. All species of the family auks (alcids) are very sensitive to oil spills. This is caused by their behaviour as well as by their very low population turnover. Therefore, protection of their breeding sites is a high priority. Moreover, the breeding population of Brünnich’s guillemot in West Greenland is seriously decreasing due to a very high hunting pressure, and the few breeding sites within the Atlas region are therefore all included. 20.2.4.2 Relative abundance of the species/species groups Some of the species are pooled into groups, as they have a similar sensitivity to oil spills. The relative abundances applied to species and species groups appear in Table 20.2. The relative abundance is the input from these site-specific shoreline species elements to the calculation of the sensitivity index for each shoreline area. Similar relative abundance values are calculated for all the biological and human use resources. 20.2.5 Example of Indexing and Data Integration: Archaeological and Historical Sites Information on the archaeological and historical sites in Greenland has been collected for over 100 years and is contained in a database under development at the Greenland National Museum and Archives. There is information on about 1500 archaeological sites in the mapped area. All known prehistoric and historic sites are included in the present Atlas, but to protect the sites only the most basic information on each site is given e.g. the site type and dating of the site. There are great differences in what is known about different archaeological sites in the Atlas area due to the source of the information. The major part of the information is derived from secondary sources (i.e. local informants) and may therefore be less accurate. Basic information on each site is often not reported and therefore the degree of sensitivity of each site is based on an estimate. The sensitivity of each archaeological site is expressed on a scale 1-3; 1. Sites that are unlikely to be endangered. 2. Sites threatened either directly or indirectly. This group includes all sites close to the coastline that are presumed to represent value either as a historical source, as a recreational site or as a special historical highlight. © 2005 by CRC Press LLC ... - tailieumienphi.vn