FEASIBILITY STUDY FOR CONSTRUCTION OF SMALL ACCUMULATION AT THE RIVER KOSEVICKA
6.4.4.5 Tercial pipelines Direct distribution to the irrigation area is provided by tercial pipelines. Total length of tercial pipelines is 7.350m. Along all tercial networks there are different diameters that vary from 250mm to 180mm. Larger diameters are usuall for longer pipelines. On every 100m on the tercial pipelines are located hydrants with exception of the first one located at 50m from pipeline beginning. While designing the irrigation area, the main intention was to ensure efficiency of irrigation system. Most of the tercial pipelines are with larger length, especially pipelines that are directly connected with the main pipeline, so it was necessary to devide pipeline to several zones with different flow, depending of size of matched area. As already mentioned, distance between pipelines is 300m, with exception of those suited over hilly terrain when the distance is less then 300m. Tercial pipelines take 53% of the total length of irrigation network. Because there is also anticipated installation of hydrants on the tercial pipelines, it can be noticed high percent (71%) of pipelines with direct contribution to irrigation. Low percent of transit pipelines gives high grade of efficiency of irrigation network. Structures of the irrigation network Hydrants Hydrants are located on such distances to enclose larger area as possible i.e. to enable irrigation with irrigation equipment and by furrow. Hydrants are with portable band and all necessary fittings and corresponding flow capacity of 25 l/s and 15 l/s. Along the network there are totally 150 hydrants. Other typical and special structures: Beside the hydrants, along the length of the pipelines there are other typical and special structures, such as: Control valves (at every joint) Air valves and outlets structures (on locations with horizontal and vertical refraction above up and down) Concrete blocks (On location where pipeline is changing its horizontal direction) Passage under ravine and river Road crossing structure (At some places where route of main pipelines as well as secondary or tercial pipelines is crossing different class of roads) Unlike the hydrants, these structures are not analysed in detail and investment value is estimated as part of installation works. 6.4.4.6 Irrigation equipment For the process of equipment selection are taken in consideration the pedologic soil characteristics, especially the wetting coefficient, the crops structure, land ownership, the existing infrastructure as roads, electricity transmittals, rivers, ravines, terrain slope etc.
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