SUMMARY

In this research the rehabilitation of irrigation system of Research and Aplication Farm of Adnan Menderes University Faculty of Agriculture was investigated involved with the climate-crop-soil properties of project area, and also it was aimed to determine the most appropriate irrigation system and water distribution method for the irrigation one. For this purpose; two different water distribution planning was made above two different irrigation schemes and totally four different irrigation project was developed.

The project area in Agricultural Faculty, Research and Application farm is nearly 141 ha. In both irrigation system, water supply is Buyuk Menderes River which flows in the north of the irrigation area.

In planning it considered to grow cotton, because this crop is widely produced in this region and also in the whole project area cotton has high evapotranspiration values. In Aydın, minimum evapotranspiration of cotton is determined 1.71 mm in October and maximum evapotranspiration is 7.68 mm in Jully. Seasonal ET of the crop is 829.7 mm and annual water requirement is 801.0 mm.

In Jully when evapotranspiration is 213.1 mm, total irrigation water requirement of cotton is 417.1 mm in open channel management system, it is 236.3 mm is pressurized management system respectively. Similar to those in August when maximum evapotranspiration is determined total irrigation water requirement is; in open channel system 417.3 mm and in pressurized system 236.4 mm respectively. Irrigation modules were 2.08 l/s/ha in open channel systems and 2.12 l/s/ha in pressurized systems for Jully and August.

Open channel system was planned as a combined system of gravitational and pressurized irrigation systems, because the water supply, topographical conditions of project area and usage of surface irrigation system were taken into consider irrigation water was. Open channel system was planned to have tree seconders and 21 manifolds connected to those. In this system’s management; in continuous flow method, system capasity was found to be 292.88 l/s. And other method (rotation method) it was found to be 925.39 l/s in 15 days irrigation period, the whole system components were sized according to these value. In the rotation method 5 rotational groups were made to irrigate equal areas in 24 hours.

High pressurized pipe system which is one of in-land water distribution systems has been designed without following contourlines in a way to ensure optimum irrigation of all plots and to bring water to land with the closet distence and the design has been made with pipes which withstand hig pressures taking that pressurized irrigation methods will be used into account. The plots have been grouped and water intake structureswith valve have been installed serving close grouped plots. All irrigation area can be irrigated with nine valves. In management of high pressurized irrigation systems continuous flow and rotation methods have been used as in open channels, and system capacity in continuous flow method has been found as 298.52 l/s and whwn the same irrigation system is managed according to rotation method the system capacity has been calculated as 1506.68 l/s. Three rotation groups have been formed to irrigate aquel areas within 1 day.

When assessing advantages and disadvantages of irrigation methods, it has been conluded that pressurized irrigation system should be used, since it uses water resources economically, it diminishes soil erosion, it allows the use of pressurized irrigation methods that have high irrigation efficiency and also it is superior over open channel irrigation method as to modernization of agricultural irrigation  although its first investments cost high.

Whwn assessing continuous flow and rotation methods, it has been concluded that continuous flow method should be used because channel and pipe lines have low capasity therefore this reduces costs, its management is easy, distribution of water is simple and operations to control are less and also it needs less and simple labor and control structures.