Long-term modeling of Soil Moisture dynamics in response to land cover changes: a case study in Telo catchment of Tehran, Iran

Aims: Soil moisture (SM) dynamics are a crucial factor in water resources management. This is complicated by the variability of land cover (LC) and land use (LU) at the watershed scale, which is the focus of this research. Materials & Methods: SM was measured at five depths across seven stations within three LU/LC types to calibrate the HYDRUS-۱D model. The calibrated model was then used to simulate SM dynamics and investigate the components of the soil water balance in the different LU/LC types from early ۲۰۰۷ to late ۲۰۲۱. To verify the model, R۲ are above ۰.۸۰ with significance level of ۵%. FINDINGS: The amount of drainage from the lower root zone was ۱۰, ۴, and ۷.۳ cm for rangeland, tree, and bare soils respectively. The results show infiltration was ۴۲, ۶۲, and ۴۱ cm, and evapotranspiration was ۳۱۷, ۵۷۴, and ۳۴۵ mm. this indicate that the highest amount of infiltration and SM storage occurred in tree land, the highest drainage from the root zone in the Rangeland and the highest surface evaporation from the bare soils. CONCLUSION: The result indicates tree-dominated LU/LC increases infiltration and soil moisture storage capacity compared to other LU/LC types. Evaporation and direct runoff losses from bare soils are greater than those from Rangeland and tree-dominated LU/LC. Furthermore, deep percolation is higher in rangeland than in tree-covered areas and bare land. In conclusion, LU/LC significantly influences water balance components and soil water dynamics, highlighting the importance of considering LU/LC in water resource and consumption management.

کلیدواژه ها:

Land use ، Evapotranspiration ، Infiltration ، Soil moisture modeling ، Unsaturated zone ، HYDRUS-۱D.