Zeszyt: 2009 / 8

Dr inż. Bogusław Michalec

SELECTED METHODS FOR SUSPENDED SEDIMENT TRANSPORT DETERMINATION

Suspended sediment constitutes about 90% of the total river sediment transport. Recognition of river sediment transport, its kind intensity is indispensable in designing, execution, and operation of objects realized for needs of water economy. It is of great importance in water reservoir silting forecast.Intensity of suspended sediment transport may be determined by use of var-ious methods i.e. direct ones - measurement methods and indirect - calculation ones. Among the direct ones the following ones may be distinguished: bathometric, photometric, electro-resistance, ultrasonic and radioisotope method. Indirect methods permit to calculate sediment transport basing upon empiric, semi-empiric and theoretical equations. Description of suspended sediment transport based on empiric investigation is connected with the necessity of introduction of hydraulic parameters describing water flow and parameters characterizing suspended sedi-ment. Introduction of these parameters into description of water and sediment movement requires consideration of their reciprocate dynamic influence. Determi-nation of water flow velocity, distribution in the river bed section, forces, and stresses acting on the bottom characterizing the beginning of movement is also significant. Distribution of suspended sediment concentration, taking into regard its granulometric composition and fall velocity of particular grains, as well as hy-draulic parameters, permit description of transport of the water-sediment mixture and ...