DETERMINATION OF RUNOFF COEFFICIENT OF BASINS BY USING GEOGRAPHIC INFORMATION SYSTEMS A THESIS SUBMITTED TO THE GRADUATE SCHOOL OF NATURAL AND APPLIED SCIENCES OF MIDDLE EAST TECHNICAL UNIVERSITY BY SEZEN ACINAN IN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR THE DEGREE OF MASTER OF SCIENCE IN GEODETIC AND GEOGRAPHIC INFORMATION TECHNOLOGIES MAY 2008 Approval of the thesis: DETERMINATION OF RUNOFF COEFFICIENT OF BASINS BY USING GEOGRAPHIC INFORMATION SYSTEMS submitted by SEZEN ACINAN in partial fulfillment of the requirements for the degree of Master of Science in Geodetic and Geographic Information Technologies Department, Middle East Technical University by, Prof. Dr. Canan Özgen ____________ Dean, Graduate School of Natural and Applied Sciences Assoc. Prof. Dr. H. Şebnem Düzgün ____________ Head of Department, Geodetic and Geographic Information Technologies Department Assoc. Prof. Dr. Nurünnisa Usul ____________ Supervisor, Civil Engineering Dept., METU Examining Committee Members: Assoc. Prof. Dr. Zuhal Akyürek ____________________ Civil Engineering Dept., METU Assoc. Prof. Dr. Nurünnisa Usul ____________________ Civil Engineering Dept., METU Prof. Dr. Uygur Şendil ____________________ Civil Engineering Dept., part time, METU Assoc. Prof. Dr. Yakup Darama ____________________ Deputy Head, DSI Dr. Elçin Kentel ____________________ Civil Engineering Dept., METU Date: (05 May 2008) I hereby declare that all information in this document has been obtained and presented in accordance with academic rules and ethical conduct. I also declare that, as required by these rules and conduct, I have fully cited and referenced all material and results that are not original to this work. Name, Last name:SEZEN, ACINAN Signature : iii ABSTRACT DETERMINATION OF RUNOFF COEFFICIENT OF BASINS BY USING GEOGRAPHIC INFORMATION SYSTEMS Acınan, Sezen M.S., Geodetic and Geographic Information Technologies Supervisor: Assoc. Prof. Dr. Nurünnisa Usul May 2008, 106 pages Turkey has very different geomorphologic, hydrologic and climatic conditions, so the runoff coefficient should be different from one basin to another. But only one constant value, which is 0.37, is being used for all the basins in Turkey. In this thesis, monthly, seasonal and annual runoff coefficients of 48 sub-basins in western and southern part of Anatolia are determined by using synchronous and average rainfall, runoff data of 26 year record period. Their temporal and spatial distributions are investigated. The relationship between the basin parameters and the runoff coefficient are also examined. Some of the basins have unrealistic large runoff coefficients, therefore excluded from the analyses. The basin boundaries and parameters are determined by using Geograhic Information System (GIS), and areal average precipitations are found by a program written in visual basic language that uses ArcObjects. The Box-Cox transformed data are used in regression analysis. There are a number of dams in the region, which affect the natural flow. Such streams are found and their sub-basins are not used in the analyses. The results revealed that there is not a strong the relationship between the basin parameters and annual and seasonal runoff coefficients for the whole region, but there are significant relations between them for some basins. Key words: Runoff Coefficient, Basin Parameters, Geographic Information System (GIS), Box-Cox Transformation, Regression Analysis. iv ÖZ HAVZALARIN AKI Ş KATSAYILARININ CO ĞRAF İ B İLG İ S İSTEMLER İ YARDIMIYLA BULUNMASI Acınan, Sezen Y. Lisans, Jeodezi ve Co ğrafi Bilgi Teknolojileri Tez Yöneticisi: Doç. Dr. Nurünnisa Usul Mayıs 2008, 106 sayfa Türkiye jeolojik, hidrolojik ve iklimsel açıdan çok farklı koşullara sahiptir. Bu nedenle akı ş katsayıları havzadan havzaya de ğişim göstermelidir. Fakat Türkiye’nin tüm havzalarındaki akı ş katsayıları için 0.37 olan bir de ğer kullanılmaktadır. Bu tezde, Batı ve Güney Anadolu’daki 48 alt havzanın aylık, mevsimlik ve yıllık akı ş katsayıları eş zamanlı ve 26 yıl ortalaması olan akım ve ya ğış verileri kullanılarak bulunmu ştur. Bunların zamansal ve konumsal da ğılımları incelenir ve havza parametreleriyle aralarındaki ili şkiler ara ştırılmı ştır. Bazı havzaların akı ş katsayıları gerçe ğe aykırı olarak büyük oldu ğundan bu havzalar analizlerden çıkarılmı ştır. Havza sınırları ve parametreleri Co ğrafi Bilgi Sistemleri (CBS) yardımıyla çıkartılmı ş ve havzaların alansal ortalama ya ğışları ArcObject içinde visual basic programlama dili kullanarak yazılan bir program yardımıyla bulunmu ştur. Box-Cox ile dönü ştürülmü ş veriler regresyon analizlerinde kullanılmı ştır. Bölgede do ğal akımı etkileyen çok sayıda baraj vardır. Üzerinde barajların oldu ğu akarsular bulunup, havzaları analizlere katılmamı ştır. Sonuçlar, tüm çalı şma alanında yıllık ve mevsimlik akı ş katsayıları ile havza parametreleri arasında çok güçlü bir ili şkinin bulunmadı ğını, fakat bazı havzalarda ise bu ili şkinin önemli oldu ğunu göstermektedir. Anahtar Kelimeler: Akı ş Katsayısı, Havza Parametreleri, Cografi Bilgi Sistemleri (CBS), Box-Cox Dönü şümü, Regresyon Analizi. v To My Family vi ACKNOWLEDGEMENTS I express my deepest gratitude to Assoc. Prof. Dr. Nurünnisa Usul for her guidance and criticism throughout the study. I would also like to thank Assoc. Prof. Dr. Zuhal Akyürek, Assoc. Prof. Dr. Şebnem Düzgün and Assoc. Prof. Dr. M. Onur Karslıo ğlu. I would also like to acknowledge, Serkan Girgin and Pınar Aslanta ş Bostan for their helps on data collection. I would also like to thank my best friends Esra Polat to take courage me and Oya Yarkıno ğlu Gücük for her support on code writing. I would also like to acknowledge, Serkan Kemeç, Gülcan Sarp, Arzu Erener, Re şat Geçer, Kıvanç Ertugay and Dilek Koç for their warm friendships. I am greatly indebted to my mother Melek Acınan, my father Soner Acınan and my elder sister Tülin Acınan for their all kinds of support. vii TABLE OF CONTENTS ABSTRACT ...................................................................................................................... iv ÖZ .......................................................................................................................................v ACKNOWLEDGEMENTS............................................................................................... vii TABLE OF CONTENTS ................................................................................................. viii LIST OF TABLES.............................................................................................................. x LIST OF FIGURES .......................................................................................................... xii CHAPTER 1. INTRODUCTION..................................................................................................... 1 1.1 Importance of the Study...................................................................................... 1 1.2 Aim and Scope of the Study ............................................................................... 2 2. LITERATURE REVIEW .......................................................................................... 5 3. STUDY AREA, DATA, RUNOFF COEFFICIENTS AND BASIN CHARACTERISTICS .......................................................................................................16 3.1 Aegean Basin......................................................................................................17 3.2 Susurluk Basin ...................................................................................................17 3.3 Gediz Basin........................................................................................................18 3.4 Küçük Menderes Basin.......................................................................................19 3.5 Büyük Menderes Basin.......................................................................................20 3.6 Afyon Closed Basin............................................................................................20 3.7 Antalya Basin.....................................................................................................21 3.8 West Mediterranean Basin..................................................................................22 3.9 The Data Used For the Study..............................................................................23 3.9.1 Digital Elevation Model (DEM) of the Study Area ....................................23 3.9.2 Streamflow Data .......................................................................................25 3.9.3 Precipitation Data......................................................................................25 3.9.3.1 Estimation of the Missing Precipitation Data..................................25 3.9.3.2 Areal Mean Precipitation ...............................................................26 3.10 Delineation of the Watershed Boundaries..........................................................26 3.10.1 Flow Direction .......................................................................................29 3.10.2 Flow Accumulation ................................................................................29 3.10.3 Stream Network Definition.....................................................................31 viii 3.10.4 Basins ....................................................................................................32 3.11 Automated Runoff Coefficient Estimation.........................................................34 3.12