Leyla Babaee, Nahideh Parchami, Raoof Mostafazadeh,
Volume 10, Issue 1 (5-2023)
Abstract
Changes in the hydrological response due to climatic parameters and human induced activities can be derived from indicators based on the analysis of flow duration curves. The purpose of this research is to determine the flood and the low flow parameters using the flow duration curves. The trend detection technique can be used as a useful tool in deterimining the temporal changes of the different hydro-meteorological parameters. The river gauge stations of the Ardabil province were used for the analysis of high and low flow occurrence in this study. The spatial variations of the flood events can be used as a preliminary guideline for the prioritization of the watershed in the vulnerability assessment and management-oriented measures. Also, the assessment of low flow condition is a useful tool in the allocation of environmental flow allocation and utilization of river surface water resources.
Methodology:
In this research, temporal and spatial changes of Q10, Q50, Q90, Q90/50 and Lane indices in 31 hydrometric stations of Ardabil province during the period from 1993- 2014 were evaluated. The flow duration curve of each river gauge stations was derived. The flow duration curves also were plotted based on the dimensionless flow divided by the mean discharge and the upstream area of each river gauge station. Also, the temporal variations of the of Q10, Q50, Q90, Q90/50 and Lane indices were analysed using non-parametric Man Kendall trend test. Then the significant level of upward and downward trend directions were determined. In this study, the results of 5 river gauge stations were presented as example based on the the river flow ranges, which includes low, medium and high river flow discharge (Hajahmadkandi, Nanakaran, Shamsabad, Polesoltani, and Booran).
Results:
Based on the results, the trend of Q10 (Flood flow index) was significant at the stations located on the main trunk of the Qarehsou river. Meanwhile the Q50 (average flow index) has a significant decreasing trend in most of the studied river gauge stations. In addition, Q90 and Q90/50 indices have a significant decreasing trend in most stations. In addition, Q90 and Q90/50 indices had a significant decrease at (p<0.05) regarding the Lane index as a flood related indicator in the Arbabkandi and Dostbeglo stations, which are affected by the dam construction there is a significant decreasing trend.
Conclusion:
I summary, the values of flood flow index in the upstream rivers of the Ardabil province had a increasing trend.
