Document Type : Research
Authors
1
Associate Professor, Faculty of Agriculture and Natural Resources, Member of Water Management Research Center, University of Mohaghegh Ardabili, Ardabil, Iran
2
Ph.D. Student, Watershed Management Science and Engineering, Faculty of Natural Resources, Urmia University, Urmia, Iran
3
Former M.Sc. Student, Faculty of Agriculture and NaturalResources, University of Mohaghegh Ardabili, Ardabil, Iran
10.22092/wmrj.2023.362093.1538
Abstract
Introduction
Understanding of the components and changes of water balance in hydrological and water resources studies is of significant importance. Climate changes and human activities affect runoff changes, water resources management and sustainable development of society. In this regard, the current research was conducted with the aim of determining and comparing water balance changes using Budyko curve in Nir watershed, Ardabil province.
Materials and methods
Budyko curve was calculated for Nair watershed in monthly, seasonal and annual time scales. In this study, the data of the rain gauge and evapotranspiration station of the watershed were also used in a statistical period of 33 years to calculate the average precipitation and evapotranspiration potential in the watershed. In the Budyko curve, the non-linear relationship that is limited by the physical limits of atmospheric water demand (PET>ET) and supply (P>ET), and the aridity index in the Budyko curve shows the long-term water balance.
Results and discussion
The results showed that, the trend of flow changes is directly related to the trend of weather components in annual time scale. Meanwhile, contrary to expectation, only in some seasons does the flow change process follow the change of climatic components. Also, the Budyko curve analysis indicated that the amount of water consumption in the studied watershed regularly deviated from its expected dependence on energy and water balance. The maximum, average and minimum ET for the studied years were obtained as 876.55, 431.85 and 277.88, respectively. Also, the maximum, average and minimum ratio of PET/P was 0.07, 0.05 and 0.02 respectively. Most of the studied years were located on the Budyko curve, where the observed water consumption (AET/P) was equal to the predicted water consumption (PET/P). According to the results, the changes in AET/P are less in the years (1981, 1983, 1989, 1994, and 2010). Based on the changes in the values of PET/P and AET/P in the Budyko curve, the watershed ability to regulate AET can be considerable.
Conclusions and suggestions
The results showed that with an increase in temperature and a decrease in precipitation. The amount of actual annual evaporation in the watershed has been increased, which has led to a decrease in runoff in the watershed. The results can be the basis for providing management solutions and adapting to the climate change in order to optimally use the available water resources. In general, it can be said that the amount of potential evaporation in the studied watershed is more than the amount of precipitation. The results of the present research can provide a basis for managing water resources under the limitations of climate change and human abstractions.
Keywords
Main Subjects
)