RESERVOIR SEDIMENTATION ASSESSMENT GUIDELINE - Aneel

Reservoir Sedimentation Assessment Guideline• COMPOSITE SAMPLE – a sample made up by the combination of all individualsamples, or sub-samples, concerning a suspended sediment measurement performedby the process of equal width increment or equal discharge increment.• DEGRADATION – the geologic process wherein riverbeds, plain areas susceptibleto floods and other water bodies bed are lowered due to the removal of material. Isthe opposite of sedimentation.• DELTA – deposit of sediment made up where there is water in movement (such as ariver outfall).• DENSITY– the mass of a substance by volume unit, ρ in kg/l or t/m 3 .• DENSITY OF SEDIMENT-WATER MIXTURE – mass by volume unit, includingwater and sediment.• DENSITY STREAM – a stream reporting high turbidity and relative density thatusually moves along the bed of a still water body.• DEPOSITION – the mechanical or chemical process through which the sediment issettled in a still water site.• DRAINAGE AREA– The area that drains to a particular point on a river or stream.• DROPPING VELOCITY – the rate of fall or deposition of a particle in liquidmeans.• EROSION – the wearing away of ground by displacement of soil and rockfragments, due to the action of water movement and other geological agents.• FINE MATERIAL– particles reporting granulometry finer than particles present insignificant quantities of bed material; usually are silts and argyles (particles finerthan 0,062mm, according to AGU).• FINE MATERIAL LOAD or WASH LOAD –part of the total sediment load madeup of granulometry not significant in terms of quantities at the bed sediment, andconsisting of material finer than the bed material. Usually, the fine material load ismade up by particles smaller than 0,062mm; nevertheless, it is a function of the loadbeing transported by the river.• FLUVIAL SEDIMENT – all solid materials transported by river water and reportingan average density close to the one for fragmented rocks: 2,65.• GRANULOMETRIC DISTRIBUTION – the frequency distribution of the relativeamount of particles in a sampling, comprised by a granulometric band, or theaccumulated frequency distribution for a given amount of particles thicker or finerthan a given size. These amounts are expressed as percentage by mass.• GRAVEL – particles of sediment ranging from 64 to 2mm according to AGUclassification. According to ABNT, argyles have granulometry ranging from 76 to4,8mm.• INTEGRATOR-TYPE SEDIMENT SAMPLER – a sampler capable of isokineticallycollecting a water-sediment mixture while its beak is moved across theflow.• NET DISCHARGE or DISCHARGE – the amount of water passing through astream cross-section in a given time.• NON-COHESIVE SEDIMENTS – sediments made up by isolated particles.• NON-MEASURED SEDIMENT DISCHARGE – the quantity of sediment load thatthe sampler could not sample.ANEEL – Brazilian Electricity Regulatory Agency / SIH – Hydrologic Studies and Information Department97