Impact Assessment of Oil Exploitation in South Sudan Using Multi-Temporal Landsat Imagery
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PFG 2016 / 4, 211 – 223 Report Stuttgart, October 2016 Impact Assessment of Oil Exploitation in South Sudan using Multi-Temporal Landsat Imagery ALEXANDER MAGER, Oberpfaffenhofen, LARS WIRKUS, Bonn & ELISABETH SCHOEPFER, Oberpfaffenhofen Keywords: remote sensing, natural resources, land cover change, landscape monitoring, South Sudan Summary: This scientific report examines the spa- Zusammenfassung: Untersuchung des Einflusses tial impacts of oil exploitation in Melut County, der Erdölförderung im Süd-Sudan auf die räumli- South Sudan, at six points in the time span between che Entwicklung basierend auf multitemporalen 1999 and 2011, based on Landsat satellite data. Landsat-Bildern. Dieser Beitrag untersucht die Three features were analysed: cropland, oil well räumlichen Auswirkungen der Erdölförderung in pads and roads. Feature extraction consisted of Melut County im Süd-Sudan anhand von sechs ver- pixel- and object-based classification approaches as schiedenen Zeitpunkten zwischen 1999 und 2011 well as on-screen digitization. Land cover classifi- basierend auf Landsat Satellitendaten. Drei Ob- cation was performed as a base for further object- jektarten wurden analysiert: Ackerflächen, Ölbohr- based classification of cropland areas and oil well stellen und Straßen. Die Objekterfassung bestand pads. Spatial analysis of the relationship between aus pixel- und objektbasierten Klassifikationsme- the detected features was performed. Apart from a thoden sowie Digitalisierung. Landbedeckungs- sharp decline in cropland areas between 1999 and klassifikationen wurden als Basis für weitere Klas- 2002, croplands increased steadily over time and sifikationen von Ackerland und Ölbohrstellen more than doubled in size. Oil infrastructure grew durchgeführt. Eine Analyse bezüglich der räumli- enormously in size throughout the whole time se- chen Zusammenhänge zwischen den erfassten Ob- ries from a single pad in 1999 to 555 pads in 2011. jekten wurde durchgeführt. Abgesehen von einem The example exhibited the potential of Earth obser- starken Rückgang der Ackerflächen zwischen 1999 vation as a tool to support the field of peace and und 2002 stieg die Fläche der landwirtschaftlich conflict research (MAGER 2013). genutzten Gebiete stetig an und verdoppelte sich in ihrer Größe. Über die gesamte Zeitreihe hinweg wuchs die Erdölinfrastruktur enorm, und zwar von einer Ölbohrstelle im Jahr 1999 auf 555 Ölbohrstel- len im Jahr 2011. Die Studie zeigt das Potential der Erdbeobachtung als unterstützendes Werkzeug in der Friedens- und Konfliktforschung auf (MAGER 2013). 1 Introduction dan People’s Liberation Movement/Army (SPLM/A) in 2005, a referendum on the 9th of Oil plays a vital role in the economy of the July 2011 ended not only this six-year interim Republic of South Sudan, which gained in- phase and four decades of bloody North-South dependence from the Republic of Sudan only conflict but even more so sealed the split of in 2011. Six years after the conclusion of the South Sudan from Sudan. Since its secession ‘Comprehensive Peace Agreement’ (CPA) be- South Sudan is the most oil-dependent coun- tween the government of Sudan und the Su- try in the world. Almost all of the state bud- © 2016 E. Schweizerbart'sche Verlagsbuchhandlung, Stuttgart, Germany www.schweizerbart.de DOI: 10.1127/pfg/2016/0300 1432-8364/16/0300 $ 3.50 212 Photogrammetrie • Fernerkundung • Geoinformation 4/2016 get is oil revenue. Right after its independence of survey are not possible due to geographic oil represented 98% of South Sudan’s state or financial considerations, or limitations in revenue. In the more recent years, the exact time. Other hindering factors might be great share is unclear because of the frequent dis- travel distances, security concerns, or both. In ruptions to the country’s oil production (EIA the above-described context the use of satel- 2014). According to the WORLD BANK (2015) lite images seems to be most suitable. How- the oil revenues currently account for around ever, so far only a few studies have document- 60% of South Sudan’s gross domestic product. ed the benefits of remote sensing within the Most of the oil production capacity is located context of impact assessment of oil exploita- in South Sudan, whose proved oil reserves ac- tion. PRINS (2009) compared Landsat satellite count for 3.5 billion barrels, being more than data for the years 1999, 2000, 2001 and 2005 twice as high as those of Sudan (EIA 2014). for parts of Melut County in Sudan and uti- Nevertheless, being a landlocked country, lized Quickbird data in order to investigate the South Sudan still remains dependent on Su- land use development during the preliminary dan. It still is forced to use Sudan’s pipelines phase of oil exploration. SERGEY & OGANES and port to export its oil. Armed civil con- (2009) and AKSYONOV (2006) investigated flicts within South Sudan and continued ten- the impacts of oil extraction on the Russian sions between the two countries, partly vio- landscape using Landsat data. Even though lent, but also disagreements over oil revenue they focus on oil spills, which is not of con- sharing have cut down oil production from cern for this study, they also captured oil in- both countries over the past few years with the frastructure from satellite data and analyzed consequence of severe economic crisis in both the possibilities and limits of doing so. Rus- countries (EIA 2014, GRAWERT 2013). sia was also the focus for HESE & SChmULLIUS The development of the oil fields took place (2009) who, amongst other features, classified against the backdrop of Sudan’s second civil oil well pads from Landsat-5 data. Landsat-7 war, which lasted from 1983 to 2005. The dis- data was used by DUNCAN et al. (2014) to as- covery of oil added a major economic compo- sess the impact of oil exploration activities in nent to the conflict and deepened the divide the Sahara. In 2014, PLANK et al. presented an between North and South. The central gov- automated feature extraction procedure based ernment in Khartoum tried to achieve full on the combination of a pixel-based unsuper- control of the oil fields, a majority of which vised classification of polarimetric synthetic is located in the South. Hence, oil exploration aperture radar data (PolSAR) and an object- was mostly limited to the central and south- based post-classification. All these studies uti- central regions of the unified Sudan at that pe- lize the principle of change detection, i.e. the riod. Thousands of people were evicted from process of identifying differences in the state their homes in order to secure undisturbed of an object or phenomenon by observing it development of the fields. Villages were de- at different times (SINGH 1989), for monitoring stroyed, people killed and thousands forceful- the different features of interest. ly displaced (RobINSON 2003, TERMINSKI 2011). This paper provides an overview of oil-re- Apart from the bloodshed, oil field develop- lated developments in Melut County, locat- ment led to big-scale environmental problems. ed in the Upper Nile region, in South Sudan Crop patterns changed, poorly constructed for the period from 1999 to 2011. The objec- roads led to drain blockages which caused tive of the study was to map human activity droughts and floods and polluted ponds pose in the context of oil extraction and to assess a danger for humans and animals alike (BICC its impacts in the area of interest (AOI). In or- 2013, ECOS 2006, ECOS 2009, ECOS 2014). der to document the spatio-temporal devel- Earth observation is capable of providing opment of the oil fields and impacts on their important information about such processes surroundings, six points in time were chosen. on the ground. Remote sensing data are used The study aimed at answering the following as an independent source of data to comple- research questions: What changes can be ob- ment local information. This is in particular served by means of remote sensing? What important for regions where traditional means spatial connections exist between those ob- A. Mager, L. Wirkus & E. Schoepfer, Impact Assessment of Oil Exploitation 213 served changes? Can they be explained with comprising of 478 villages as well as parts of existing knowledge about events related to oil the counties Renk, Maban, Baliet, Fashoda. production? In order to answer the questions, Melut County historically has been inhabited a three-step approach was followed: (1) An in- by Dinka. After the signing of the CPA and itial land cover classification was performed the formation of the Government of South- in order to gather core environmental infor- ern Sudan (GOSS) the former seven sections, mation; (2) classes of interest were extracted which were governed by paramount chiefs of using both semi-automatic (pixel- and object- various Dinka sub-groups, were turned into based) and manual classification techniques, seven Payams. Two Paymas, Melut and Pa- and (3) the extracted features were being used loich, are of special interest to this study. to map the state of the AOI at the aforemen- The Dinka of the northern Upper Nile re- tioned points in time and to analyse the rela- gion practise agriculture more than cattle tionships between them. One key assumption breeding and hunting. They adopted to the of this study is that the development of oil in- climate conditions in this area in a way that frastructure leads to a loss of cropland areas they move between areas near to the river Nile (ECOS 2011, 2014). Taken together, an over- during dry seasons and the areas of their or- all picture of the situation and its development igins during rainy seasons where they then over time was expected to emerge. practised agriculture (ECOS 2014). Agricul- ture, which was largely practised in this area, vanished almost entirely during wartime due 2 Study Area to forced displacement of locals by the Suda- nese Armed Forces (SAF). According to PRINS The majority of south-sudanese oil reserves (2009), the same is true for the Western Upper are located in the oil-rich Muglad and Melut Nile region of South Sudan, where oil conces- rift basins, which extend also into the Repub- sion Block 5A is located.