4/11/2024 0 Comments Grid type drainThe interceptor should be laid along bottom of permeable layer.ġ) Hydraulic conductivity of soil horizonsĢ) Depth of drain below the ground surfaceĥ) Joint spacing between tile drains (generall圓 mm)Ħ) Depth of impervious layer below the ground surface. Interceptor: Deep drenches are tiles, are used to intercept seepage water from the hillside. Placing the main on each side of depression serves a dual purpose intercept the seepage & provide outlet for the laterals. This system is used on flat land/regularly shaped field on uniform soil. Laterals enters the main only from one direction hence the cost of this system is comparatively less. The main line or sub main lies in the narrow depression, particularly suitable where laterals are long & required area to be thoroughly drained. Herring bone system: it consists of parallel laterals that enter the main from either side at angle. The lines (drained files) are laid some what randomly to drain these depressions generally the main line follows largest natural depression of the field and sub main & lateral connects the scattered spot with the main.įor drainage areas, individual low depressions, spots can be drained using herringbone or grid iron system. This method issued to drain the scattered wet spots in the field. Many times under field condition combination of surface & subsurface drainage may be required. Subsurface drainage will essentially required when the land is flat or when surface drainage is not possible also if is pervious, underlined by impervious strata, subsurface-drainage is required.ĭeep trenches or tile drainage are the two essential means for subsurface drainage. Subsurface drainage: 1) tile drains 2) open ditchĬlassification of Obligate Parasites in Fungi Surface drainage: 1) flat flow 2) interminable strata with pervious soil The spacing is around 360m when water is moving towards both the sides in the drains. Generally, ‘V’ shaped trapezoidal or parabolic drains are constructed having minimum depth 22.5 cm & cross at area 0.5 m2. Poorly drained soil with numerous shallow depressions The ditches are not at equidistant and such system is adapted to flat. The spacing of collected drains is generally 90m for flat land to 300m for sloppy lands.ĭitch is speed further apart and has greater capacity than the dead furrows. The collected drains collect the water from dead furrows to carry them out from the field. The direction of ploughing should be paralleled to dead furrow, whereas tillage operation likes sowing, planting, perpendicular to dead furrow. Soils having low infiltration rate & soils horizontal having less permeability require the drainage facility. Structure: platy structure soils poor drainage characteristics whereas blocky & granular soil structure exhibits good drainage property. Texture: fine texture soil requires artificial drainage where as coarse textured soils may not require the artificial drainage. Permeable soils do not require artificial drainage unless the water table is high slow permeable soil often requires drainage specially when rainfall is high & field is leveled. Role in deciding the extent & type of drainage system required. The artificial drainage is required to be provided for two reasons Humid regions having high rainfall continuous or intermittent. Humid regions where rainfall is less than evaporation. 2-4 hours for vegetable)Įxcessive moisture content above the field capacity. (When the water stands on the land surface for long period e.g.
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |