Batman Çayı’nın taşkın analizinin HEC-RAS programıyla yapılması

Abstract

Taşkınlar, tropikal iklim kuşağında yer alan ülkelerin yanı sıra Türkiye gibi bu iklim kuşağının dışında yer alan ülkelerde de hem sayı olarak hem de verdiği zararlar açısından bir artış göstermektedir. Artan nüfus yoğunluğuyla beraber çarpık yerleşim bölgelerinin artmasıyla bu taşkınlar sonucu can ve mal kayıplarının da yaşanmasını kaçınılmaz hale getirmektedir. Özellikle son yıllarda hayatın her alanına girmeye başlayan Coğrafi Bilgi Sistemiyle, taşkın risk analizlerine dayalı risk haritaları yerleşim planlamalarında esas alınan öncelikli etmen olmaya başlamıştır. Bu çalışmada, Batman Çayı’nın Yeni Malabadi Köprüsü ile Diyarbakır – Batman Karayolu Köprüsü arasında kalan kesimine ait taşkın analizi yapılmıştır. Düşük bir eğimle (J≈0.00019) menderesler çizerek sık sık akım yatağı değişen Batman Çayı’nın, Batman İl merkezi de dahil olmak üzere birçok yerleşim yerine sınırı bulunmaktadır. Bu da, yüksek bir debiye sahip olan Batman Çayı’nda zaman zaman can ve mal kaybına neden olmaktadır. Çalışma yapılan bölgeye ait 1/1000 ölçekli haritada AutoCADCivil 3D programıyla toplamda 165 adet enkesit alınmıştır. Elde edilen bu enkesitlerle, HEC-RAS (Hydrologic Engineering Centers River Analysis System) programı yardımıyla Batman Çayı’nın tek boyutlu taşkın hidrolik analizi yapılmıştır. Değişik feyezan değerlerine bağlı taşkın zararlarının alansal değişimleri göz önüne alınarak mevcut dereye ait doğal yatakta Q5, Q10, Q25, Q50, Q100 ve Q500 taşkın tekerrür debilerinde su üst yüzünün geldiği kotlar belirlenmiştir.

Keywords

• Batman Çayı, HEC-RAS, taşkın analizi

Floodplain analysis of Batman river with HEC-RAS program

Abstract

Since the beginning, people have preferred residential areas close to the water resources of the indispensable qualities for permanent living. As a result, it is made interfere with the natural water beds. Beside of meteorological and geomorphological structure of the basin, flood under human intervention cause losses of life and property inevitability. As a result of global warming, besides the meteorological events such as extreme weather events it is expected that the frequency can be of significant increase in the activity area of floods. Floods are seen as the greatest natural disaster in the worldwide after earthquakes. Especially country like Turkey, as well as in terms of both climate and geographical features changing in a short distance, flood is the most decisive parameter in the localization planning. With the increasing awareness, there are more accurate studies intend to on early warning systems and reduce damage of flood under the "Flood Risk Management". Especially in the case that permeates every aspect of life are increasingly, the Geographic Information System is use with flood plain analysis. In nature, the size of river does not cause excessive flood. However, as a result of human intervention river cross-section area is decrease and major flood can occur. The main cause of this problem is incorrect application of zoning and land use as settlement. Depend on founding petroleum there have been major and rapid growth in Batman city. After this unplanned growing, there have been disorder in urbanization of the city and people settle in river bed areas. As a result of this situation, there are a significant amount of life and property losses. In 2006, the flood in the city centres, there were 10 people dead and great material damage. In this study, the floodplain analysis of Batman River between New Malabadi Bridge and Diyarbakır – Batman Highway Bridge was performed. With a lower slope ( J=0.00019) and a lot of meanders Batman River, which close to the several settlements including the city centres of Batman, frequently changes its current bed. High flow rate in Batman River cause loss of life and property. 165 cross-sections is taken from the map of the study area with AutoCAD Civil 3D program. After export these cross-sections to the HEC-RAS (Hydrologic Engineering Centres River Analysis System), one-dimensional floodplain analysis of Batman River is obtained. Under the different flow rate, a spatial variation of flood damage is provided. Floodplain risk analysis determine water surface profile in the natural bed of the river under Q5,Q10, Q25, Q50, Q100ve Q500 flow rates. According to the analysis result, capacity of crosssections of Batman River isn’t passed more than Q50 flow rates. Because of its geological formation is semi-permeable and impermeable, flood infiltration to the ground water is prevented. As a result of river bed is used by human as sand pits, residential or agricultural areas, there can be losses of life and property every rain season. Especially the area between station km: 20+700 – 21+211 and 9+300 – 9+950 is have higher water depth because of the flatness of the section base, it was observed that inundated a large area. This part of the river bed to the corresponding Şerbet and Bıçakçı Villages is under serious risk of flooding.

Keywords

• Batman River, HEC-RAS, floodplain analysis