International Commission on Irrigation & Drainage Commission Interationale des Irrigation et du Drainage

Multilingual Technical Dictionary (MTD)
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Term No.Term Name/Term DescriptionAction
872
Retention
That part of the precipitation falling on a drainage area which does not escape as surface stream flow, during a given period. It is the difference between total precipitation and total runoff during the period, and represents evaporation, transpiration, subsurface leakage, infiltration, and when short periods are considered, temporary surface or u.....
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1097
Field capacity, Normal field capacity, Normal moisture capacity, Maximum field carrying capacity, Field capillary (moisture) capacity, Effective water-holding capacity, Specific retention
1 - The amount of water held in the soil after the excess gravitational water has drained away and after the rate of downward movement of water has materially decreased. Essentially the same as `specific retention`, a more general term used in studies of groundwater, except that specific retention is generally given as a percentage by volume wherea.....
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1264
Retention dams
Small earthen dams designed to retain water for only short periods of time to prevent excessively rapid runoff and erosion......
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2360
Hydraulic fill dams
An earthfill dam in which the fill is excavated, transported and placed in the dam by dredging, sluicing or pumping during construction. The fines are generally segregated and deposited towards the centre of the dam for greater imperviousness......
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2411
Retention water level, Top water level, Normal top water level, Full supply level, or Normal water level
The lowest crest level of the sill for a reservoir that has a fixed overflow sill. In case the outflows are wholly or partially controlled by movable gates, syphons or other means, the maximum level to which water can rise under normal condition excluding the provision for flood discharge in the retention water level......
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2572
Trial load twist method (for gravity dams)
It is based on the assumption that the water load is divided between a structural system made up of vertical and horizontal elements with each system occupying the entire volume of the dam. For ungrouted joints there are two systems, the cantilever structure and the twisted structure. The grouted joints have three systems, the cantilever structure,.....
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6532
Absorptive terrace, or Retention terrace
A terrace of variable cross section constructed by excavating on both sides of the ridge, formed and designed primarily for the retention and spreading of moisture over the widest possible area......
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7384
Retention time
The period of time wastewater takes to pass through a pond or other treatment process; calculated by dividing its volume by the flow rate.  .....
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7879
Retention basin
A basin or reservoir where water is stored for regulating a flood. Unlike a detention basin, it does not have outlets for releasing the flows, the water must be disposed by draining into the soil, evaporation, or pumping systems. .....
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8042
Retention facility
A surface water runoff storage facility that always contains (retains) a substantial volume of water to serve recreational, aesthetic, water supply, or other functions. Surface water is temporarily stored above the normal stage during and immediately after runoff events. Examples of retention storage facilities include ponds and small lakes in resi.....
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