Coğrafi Bilgi Sistemleri (CBS); konum ve konuma bağlı her türlü bilgiyi içerebilen, güçlü veri tabanı olan bir sistemdir. CBS aynı zamanda bu verileri coğrafyanın bilimsel ilkelerine bağlı olarak grafik, profil, istatistik, harita, üç boyutlu görüntü vb. şekillerdeki analizler ile işleyebilmektedir. Bu çalışmada, CBS yöntemi, coğrafyanın temelini oluşturan fiziki coğrafyanın özelliklerini yansıtmak amacıyla ele alınmıştır. CBS ile oluşturulan “Sayısal Yükselti Modeli” sayesinde havzanın, belirli bölümlerinin yükselti, eğim ve bakı özellikleri ortaya konulmuştur. Havza alanı ve karstik havza sınırı en doğru biçimde belirlenmiştir. Çeşitli analizler ile havzadaki farklı vadi tipleri, drenaj şekilleri, akarsuyun boyuna ve enine profilleri, ana akarsu ve kollarının uzunlukları ortaya konulmuştur. Akarsu şebekesinin kuruluşunda ve kaynakların dağılışında topoğrafya ve jeolojik yapının etkisi tespit edilmiştir. Havzanın gelişiminde etkili olan fayların ve sürüklenim alanlarının uzunlukları ile litolojik yapının özellikleri, dağlık, platoluk, tepelik sahaların kapladıkları alanlar ile yükselti ve eğim özellikleri belirlenmiştir. Şahit tepe, sırt, amfiteatr oluşum, ovalık saha, falez, gömük menderes, kıyı topoğrafyası, karstik alan, dolin, obruk, mağara, traverten sahası, toprak ve bitki örtüsüne ait özellikler; belirlenmiştir. Aynı zamanda bu şekillerin oluşumlarında; yükselti, eğim, bakı, topoğrafya, jeolojik yapı, hidrografik yapı ve iklim etkisi irdelenmiştir. Bu araştırma ile CBS yönteminin, fiziki coğrafya alanına sunduğu imkânlar ana hatları ile belirlenmiş, CBS’nin, coğrafya biliminin ele aldığı problemlere etkili çözümler sunabileceği belirlenmiştir. Coğrafyanın, CBS teknolojisi ile elde edilecek bilimsel verileri, günlük yaşama kolaylıkla aktararak günlük yaşamda da kullanımı artan bir bilim haline geleceği sonucuna ulaşılmıştır.

Geographical Information Systems (GIS) employ very powerful data base management systems, which can acquire all kinds of data about the locations and includes all kinds of location related information. GIS at the same time can manipulate profiles, statistics, maps, 3 dimension views and different kinds of operational analysis as a system depending on basic scientific principles of Geography. For these reasons GIS as a methodology, is handled as an infrastructure formative of Geography with a view to identifying the physical geographical features. Owing to digitized terrain database “Digital Elevation Model” model of GIS, the elevation, slope, aspect properties of the reservoir are displayed. The boundaries of the carstic reservoir area are also identified as correct as possible. It has been determined that the area of the region from which Sorgun Stream and it’s branches collects water is around 500 sq km’s wide which extends in the North - South direction. Whereby various analyses the different valley types within the reservoir, drainage patterns, longitudinal and crosscut profiles of the watercourse, the lengths of the main river and branches are displayed. Therefore, it was designated that Sorgun Stream has a main river length of 79 km’s between it’s spring at 2350 meters altitude and it’s river mouth and has a total length of 966 km’s with all it’s branches. Effects of topography and geological structure in the formation of running water system and distribution of water resources are displayed. It has been determined that the sources of the surface waters of the reservoir are cosequent streams and the evolution of the watercourse network depends on and extends towards the areas of week soil structure. The watercourse settled itself on the structure formed different drainage systems. It has been determined that the difference in the drainage systems is due to the change of the general slope of the area towards south-west direction with epeirogenesis, which was towards South direction before Tertiary. The effects of faults and lengths of drifting areas, characteristics of litolojik structure, footprint of mountainous, plateau, hilly grounds areas which were effective in the formation of the reservoir are also determined. The properties of butte, crest, amphitheatre formation, plain area, cliff, meander, shore topography, carstic area, doline, cave, travertine area, ground and plant characteristics, field, length, amount and assortments are determined. At the same time, the effects of heights, slope, aspect properties, topography, geologic structure, hydrographical structure and climate are identified. The 8 km long straight coastline extends at the south of the reservoir in the north-east to south-west direction. The Plato seen at -20 meters depth in the sea starts at a distance of 200 meters from the west side of river-mouth of the Sorgun Stream and causes the existence of a shallow sea. Reservoir at the western of the generated wide and shallow sea at the western section of the Erdemli lowland. It has been observed that, with 326 sq km wide area the tertiary terrain puts forward the general character of the reservoir which is followed by 154 sq km wide Mesozoic terrain and 19.3 sq km wide Quaternary terrain. Reservoir also contains 4 explicit fault and 3 drifting areas. Elevation of the reservoir varies from 0 m to 2420 m and %70 of the reservoir area elevation is higher than 1250 m which corresponds to 343 sq km wide area. The distribution slope of the area of the reservoir varies as follows : - % 26 of area have a slope of 0 degree to 5 degrees - % 52 of area have a slope of 5 degrees to 20 degrees - % 14 of area have a slope of 20 degrees to 30 degrees - % 8 of area have a slope over 30 degrees. Depending on the formation of the reservoir, the aspect shows different characters at the east end west of the Sorgun Stream and the detailed topographic structure causes varying properties of aspect. At the entrance from the Erdemli Plain to main valley; first the gorge with hillsides of average 200 m high, then the canyon extending from north to south direction with hillsides lined off cornice and towards the interior “V” type valleys takes place. The forest area of the reservoir totals to around 351 sq km and alluvial and organic soil area totals to 2 sq km. Around 1/7 of the area of the reservoir extends without any soil on it. Slopes more than 30 degrees are very effective for hillside erosions and such hillsides forms around % 8 of the reservoir area. It has been observed that the characteristic plants of the Sorgun Stream reservoir are red pine (Pinus brutia), black pine (Pinus nigra), oak (Quercus), juniper ( Juniperus sp.) and cedar (Cedrus libani). During this research study the inconsistencies between various data collected by the several Governmental institutions was noticed. For example, while the 2000 m elevated area laying at the west of the track extending from Geriz Yaylağı to Kemer Yaylağı, was shown as soilless area by General Directorate of Rural Services; the General Directorate of Forestry has described this area as the agricultural area. Furthermore, the General Directorate of Forestry described the areas of higher than 300-400 m steep cornice at valley hillsides as agricultural areas. One of the most interesting facts of the reservoir is that depending on the special topographic conditions the existence of the mountain alders, “which are the characteristic plants of the Black Sea climate” at the southwest of the lower path. By means of this research the main features of the presented possibilities by the GIS methodology for the field of physical geography are determined; therefore the reality that “GIS and Geography are founded on common scientific bases” were designated. The reached conclusion was that, owing to the advanced technology of the GIS methodology the scientific geographical information can easily be transferred to daily life and can be used as a living Geography.