Appraisal of the Trend of Soil Infiltration Rate Changes in Flood Spreading Stations of Iran

Flood spreading stations were constructed in Iran with different objectives such as groundwater recharge and vegetation recovery. Accumulation of sediment can be a major problem in flood spreading stations. According to generally accepted theories, floods and salt pollution can reduce gradually the infiltration rate. In order to investigate this issue, 13 flood spreading stations were selected across the country and infiltration rate changes were monitored over five years in the flood spreading areas. Non-parametric tests were used to analyze the abnormally distributed data. Based on the soil properties of the spreading stations, stations were first classified into three groups separately by cluster analysis; next, studies were conducted in three separate groups. Results in stations group 1 showed that, in the first year, the infiltration rate among spreading lines was not significantly different, but data for the second year showed a significant difference at α = 0.05. For stations group 2, in the third year, the difference in the infiltration rate was significant at α = 0.05. In addition, changes in the infiltration rate were significant at α = 0.05 in stations groups 1 and 2 in the second spreading line. For stations group 3, significant changes among lines have been detected. Results also showed that changes in the infiltration rate in different years were somewhat different among the three groups of stations. Although infiltration rate changes were low, there was a general decreasing trend.