Katı madde taşınımı, kanallarda oyulma ve birikmelerde, barajların ekonomik ömürlerinin belirlenmesinde, köprü ve viyadük ayaklarında yerel erozyonların hesaplanmasında, su temini ve atık suyun uzaklaştırılması projelerinde, su kalitesinin belirlenmesinde, denizlerde delta oluşumunda, dere ıslah projelerinde büyük rol üstlenir. Bu sebeple ekonomik, çevresel ve sosyal faydalar açısından katı madde hareketinin başlangıcının, şekillerinin ve taşınan katı maddenin miktarının belirlenmesi çok önemlidir.Katı madde su tarafından bir kanal içerisinde taşınır. Bu kanal doğal oluşmuş ya da insan yapımı olabilir. Doğal oluşmuş veya insan yapımı kanallar farklı amaçlar için farklı malzemeden, ebatlarda, eğimden ve enkesit şekillerinden oluşmuş veya oluşturulmuş olabilirler. Kanalların her bir özelliği, katı madde taşınımı için ayrı bir rol oynar.Katı madde taşınımından bahsedebilmek için öncelikle bir katı maddeye ve bir su akışına ihtiyaç vardır. Lakin her katı madde ve su akımı buluşmasında katı madde hareketinden söz edilemez. Katı madde hareketini kontrol eden koşullar vardır. Bir katı maddenin harekete başlaması için akım koşullarının katı maddeyi harekete geçirecek kadar güçlenmesi gerekir. Bu kritiğe harekete başlama kriteri denir.Katı madde harekete başladıktan sonra akım koşullarına bağlı olarak kanal içinde su vasıtasıyla farklı şekillerde taşınabilir. Bu taşınma şekilleri, katı madde yatak tabanı ile ilişkisi kesilmeden taşınıyorsa taban malzemesi hareketi, kanal yatağından bağımsız su ortamı içinde taşınıyorsa askı hareketidir. Bir katı madde harekete başladığında ilk olarak taban malzemesi hareketi yapması beklenir. Bu yüzden taban malzemesi hareketi ile hareketin başlaması birbirleriyle ilişkilidir.Bu tezde, akarsularda katı madde taşınımının temelleri hakkında tezin daha iyi anlaşılabilmesi için literatür özetlendikten sonra kanal enkesit şeklinin etkisini incelemek için farklı hidrolik yarıçaplarda, şev açılarında, taban genişliği ile derinlik oranlarında üçgen ve trapez kanallar oluşturulmuştur. Katı maddenin harekete başlamasını ve başlayacağı yeri belirlemek için kayma gerilmeleri dağılımları; kayma gerilmesi dağılımlarını belirleyebilmek için ise metotlar araştılmıştır. Kayma gerilmeleri dağılımlarını bulmak için Birleştirilmiş Dikmeler Yöntemi (Merged Perpendicular Method) ve Yang ve Lim'in Yöntemi denenmiş; bu tezde Yang ve Lim'in Yöntemi kullanılmıştır. Harekete başlama kriteri kanal şevinlerinde ve tabanında incelenmiştir. Çıkan neticeler ışığında kanal genelinde ve yerel noktalarda hareket anlayışıyla taban malzemesi(yükü) debileri karşılaştırılmıştır. Her bir incelemede değişen kanal özelliklerinin etkisi gösterilmiştir. Water is life and our lives depends on water. While our dear planet Earth having troubles because of us and before generations, we should not be allowed to waste any source of water. Not only water that we are as humans wasting, we are wasting natural sources, energy and time. We are building structures with or without a future. Over design can be a waste of sources and money but lack of design can put more dangerous results when it comes to water in any aspects. So here comes the importance of understanding the nature of water and not to act like we can rule it while water can build our lives or destroy since the beginning of life.We are building dams for water collection or energy production mainly, or building irrigation channels, sewers, ports but there is an insidious way of water: sediment transport. Sediment transport plays a great role in the erosions and accumulations of streams, at determination of economic life of dams by depositions in dams, local erosions on the feet of bridges can cause collapse and viaducts in water supply and waste water disposal projects, determination of water quality, delta formations at the seashore. Therefore, in terms of economics, environmental and social benefits, it is very important to determine the ways of the sediment transport, initiation of sediment transport and the amount of sediment being transported.The sediments are carried by water in a channel. This channel can be either naturally formed or man-made. Naturally formed or man-made channels may be formed for different purposes from various materials, different sizes and cross-sectional shapes. Each feature of the channel plays a different role for sediment transport.In order to be able to talk about sediment transport, first there must be a sediment and water flow. However, it cannot be said there is a sediment transport in every meeting of a sediment and water flow. There are conditions that are controlling sediment transport and have to be satisfied. The current conditions need to be strengthened enough for a sediment to initiate its motion. With a basic explanation, it can be said that forces to move sediment has to be equal or greater than the forces that keep sediment stabile. Truly, nature of sediment transports is very complex. Even angularity of sediment can affect initiation of motion while there is turbulence, double-phase-flow and more. More often initiation of motion is checked with a parameter called Shields parameter. If the sediments Shields value exceed critical Shields value, it can be said there is motion. Sediments Shields value is a non-dimensional boundary shear stress by dividing the shear stress that acting on the sediment to sub-merged unit weight and diameter of sediment. Critical Shields is found on Shields curve by grain Reynolds number. If sediment is stand on a transverse slope, critical Shields value will change due to transverse angle of channel and friction angle of sediment.After a sediment initiated its motion in the water, it could be transferred by different transport types. This transport types are, if the contact between sediment and channel's bed are not lost yet, then it is bed load transport; if the contact between sediment and channel's bed are lost, then it is suspended transport. When a sediment starts to initiate its motion, first of all, it is expected to move as bed load transport. For that reason, bed load transport and initiation of motion are related.In this thesis, after giving the literature summary to get a better understanding of basics of sediment transport, channels with different cross-sectional shapes, changing transverse slope angle, channel bottom base width and water depth ratio, internal friction angle of the channel bed material and hydraulic radius values are created. For the initiation of solid material movement on the channel base, transverse slope and across the channel are examined by the understanding of motion in the general channel and the locals of channel. The bed load flow rates are examined using analytical methods.To examine the effects of the cross-section, 12 different triangle-cross-sectioned channels and 48 different trapezoidal-cross-sectioned channels (in terms of hydraulic radiuses, base bed width to depth ratios and side slope angles), have been created. Methods for boundary shear stress distributions on the wetted perimeter of the channels have been searched. For determining, boundary shear stress distributions on wetted perimeter, Merged Perpendicular Method (MPM) and Yang and Lim's Method (YLM) have been tried. Due to the lacks of MPM, MPM could not be used. Because of easiness and analytic way of Yang and Lim's Method, YLM have been used in this thesis. There is an important point in YLM which is maximum shear stress on transverse slope and flatbed is equal to each other. After boundary shear stress distributions found on 60 different channels, initiation of motion has been examined at channel's bed and side slopes by using Shields parameter. Because of critical Shields parameter is lower on transverse slope than on flatbed and besides shear stresses are equal on bed and transverse slope; it is seen that motion initiation on transverse slope is starting earlier than on flatbed. After finding out this, to compare the general and the local of channels, a slope called `critical slope` is calculated. This critical slope refers to the minimum slope that can initiated single sediment movement on a surface of transverse slope or flatbed or general channel. This critical slope is going to help finding bed load transport rates difference between local (transverse slope or flatbed) and general (channel). In the light of the results, bed load discharged of concept of the local point's movement and bed load discharged of concept of overall channel movement have been compared and it is seen that concept of `general` or `average` concept of thinking and designing is not enough to say `there is no bed load transport due to no motion`. Also, it is shown transverse slopes, that generally neglected by general concept, have significant role on bed load transport due to the early initiation of motion on them. Examinations show the effects of different cross-sectional shapes, changing transverse slope angle, channel bottom base width and water depth ratio, internal friction angle of the channel bed material and hydraulic radius values that are the basic channel properties, in bed load transport.Overall, this thesis showed effects of channel crossection on intitation of motion and bed load discharge in a simple way. With this regard this thesis study can be considered as a first step to understand the influence of channel geometry on the mobility of the bed sediment. Results proved that the effect of channel geometry cannot be overlooked, especially when the channel is not very wide. 402