Water-inflow ditch

WATER-INFLOW DITCH (EN: water diverting trench, derivational channel; DE: Wasserzuleitungsgraben; FR: fossé d'ecoulement; ES: canal de derivacion; RU: водозаводная канава) is the hydrotechnic built structure for the water supply with the natural pressure for the means of the hydraulic mechanization, for the dredging polygons, for the installations for the water thawing of the frozen rocks, and for the flushing installations at the mines.

The route for the water-inflow ditch on the terrain is laid, while taking into account the ensuring of the free-flow delivery of the water from the source of the water supply to the point of the consumption (the longitudinal gradient is 0.001-0.002). The speed of the movement of the water through the water-inflow ditch is 0.7-1.5 metres per second (depends on the gradient). The area of the cross section of the water-inflow ditch is determined, while taking into account the consumption, and the specified speed of the movement of the flow of the water. The shape of the cross section is the trapezoid with the angle of the slopes of 35-45 degrees. At the segments of the route of the water-inflow ditch with the unstable, easily water-eroded or cracked rocks, which are having the high coefficient of the filtration, there are constructed the wooden linings (gutters). For the passage of the water flow through the lowlands and ravines, which are encountered along the route, they use the overpasses or pipe crossings. The length of the water-inflow ditch may be determined from the expression

where

Hg is the geodesic pressure, metres;

Hr is the excess of the level of the bedrock (underlying rocks) of the placer above the level of the water within the river, metres;

ir is the gradient of the valley of the river;

ik is the gradient of the water-inflow ditch.

The consumption of the water, depending on the cross section of the water-inflow ditch, is within the limits of 0.5-1.5 cubic metres per second. For the intake of the water, they construct the small dam, which ensures the rise of the water of 0.5-1.5 metres, and the steady inflow of the water into the water-inflow ditch.