Background and objective: Trend analysis is an important tool to obtain reliable information about the future flooding events in watershed areas. Trend analysis tests can provide valuable information related to potential future flooding events for designing and developing the flood risk reduction measures and early warning systems. The main purpose of the present study is to apply trend analysis on the annual peak discharge in Jajrood watershed.

Methods: In the present paper, annual peak discharge data were used at hydraulic gauging stations of Kamarkhani, Bagh Tangeh, Rudak, Latian, Narvan and Ali Abad – Lavark. Mann-Kendall and Sen Slope tests were employed during the trend analyses.

Findings: the results indicate that linear trends are positive for all stations except Bagh Tangheh during the study period. According to the Mann-Kendall’s and the Sen’s slope tests results, increasing trend of data was significant in Kamarkhani station at level of 95% and in Aliabad - Lavarak station at the level of 99.9% .

Conclusion: Investigating the annual peak discharge trend can be used as an effective factor for developing flood warning systems, flood related policy making, and agricultural insurance.