Technical evaluation of sprinkler irrigation system on farm ( Isfahan and Hamadan Provinces)

Background and objectives :In several fields of Isfahan and Hamadan provinces, due to lack of proper design and hydraulic shortcomings of sprinkler system, the efficiency system is unacceptable and causes ponding of water on the land and runoff from the field. Therefore, in this study, some of the existing sprinkler irrigation systems in Fereidan and Bahar regions were evaluated.
Materials and Methods: In this research, nine and ten potato fieldsin Isfahan (Fereidan Region) and Hamedan (Dashtebahar Region) Provinces respectively were evaluated for 2 years.Soil physical characteristics such as soil texture andsoil permeabilityat field sites were measured in the Isfahan and Hamedan Soil and Water Laboratory. Also sprinklerirrigation systems in these fields were investigated. From soil characteristics in Frieden region could be noted to medium soilpermeability(1.5 to 2.0 cm.hr-1) andsoil texture (medium to heavy). Thesprinkler irrigation was permanentclassic system.Soil texture (loam, clay loam, silty loam, silty clay loam)and the existing irrigation system were reported moveable classic and wheel move sprinkler irrigation. Irrigationsystems assessments weretaken place according to Merriam and Keller methodology (1978) (5).Uniformity coefficients, potential and actual application efficiency of low quarter (PELQ، AELQ، CU and DU) were determined.The hydraulic system parameters consists of H, Q and P were measured.First of all, soil moisture in the experimental sites to determine the soil moisture deficit (SMD) was measured.Pressureandflow ratesprinklersatthe beginning, middleandend of theirrigation experimentsas well as in fieldswere measured.Aftertwohours, sprinklers pressure,flow rateandvolume of waterinthecanswere measured.The uniformityandefficiencyof thesystemswere calculated as well.
Results: Nine sprinkler irrigation systems were evaluated and DU, CU, AELQ and PELQ in the fields were equal 60.8%, 57.2%, 75.3% and 66.2% respectively. The results indicated that the poor PELQ was mostly due to lack of sufficient knowledge of the operators about optimal use of the irrigation system including control of inlet pressure, simultaneous operation of too many sprinklers and inappropriate duration of each sprinkler operation. All these factors led to deviation from the designed irrigation time and interval. The low values of DU and CU could be attributed to insufficient pressure and discharge of irrigation systems. In sprinkler irrigation system, the main difficulties in implementation of this system are lack of accuracy in design and insufficient knowledge of users. Ten sprinkler irrigation systems were evaluated in Bahar plain and PELQ, AELQ, CU and DU in the fields were equal 53.0%, 45.6%, 81.1% and 77.1% respectively. Average of PELQ, AELQ, CU and DU in the weel move systems were equal 55.1%, 51.1%, 66.7% and 81.4% and solid systems were equal 52.1%, 43.3%, 73.0%, 81.0% respectively.
Conclusion: Results show that the poor AELQ was mostly due to economics. Poor DU and CU were mostly due to Low pressure and sprinkler's discharge in fildes.
Keywords: Isfahan, Hamadan, Potato, Sprinkler irrigation, Technical evaluation.