Iranian Water Research Journal

Iranian Water Research Journal

Determination of the best fit function for uniformity coefficient and distribution uniformity of sprinkler irrigation systems in Dehgolan Plain of Kurdistan

Authors
Gooran Yamin-Moshrefi
Isa Marofpoor
Hooshang Ghamarnia
Arsalan Faryabi
Abstract
Several studies confirm the negative effects of non- uniform distribution of water on crop productivity and deep percolation. This means that some parts of the farm get more water than required on the other hand, other parts of the farm suffer from under- irrigation and water stress. In this research, the best fit functions for prediction of Uniformity Coefficient and Distribution Uniformity obtained using 20 randomly selected pressure conduit irrigated farms in Dehgolan plain (10 classic sprinkler systems and 10 wheel move systems). The measured Uniformity Coefficient and Distribution Uniformity were compared by fitting normal, uniform and beta distributions functions. The results show that normal distribution has the best fit line in predicting the Uniformity Coefficient and Distribution Uniformity in all the 5 settlements in the10 wheel move farms with spacing of 9, 12, 15, 18 and 21 meters as well as in the 10 farms with classic sprinkler systems,. In all of three cases, normal distribution functions have the most accuracy in prediction of Uniformity Coefficient and Distribution Uniformity. Also the accuracy increased in wheel move system with decreasing the space between two frequent settlements.

  • Receive Date 12 October 2009
  • Revise Date 17 June 2010
  • Accept Date 11 July 2010
  • Publish Date 22 June 2010