Purpose: To develop a rockfill dam hydraulic calculation method based on the latest research on filtration erosion rate in coarse-grained materials at the contact with surrounding soils as well as the dependence of the geotextile filtration properties in the frozen state on its water loss coefficient. Methods: The erosion rate at the contact of coarse-grained materials with clay soils is proposed to be calculated by the formula developed at the Vedeneev All-Russia Institute of Hydraulic Engineering. The geotextile filtration properties in the frozen state have been tested using the water loss coefficient of these materials. Results: The proposed dependence for calculating the erosion rate of soils at the contact with coarse-grained materials has been obtained specifically for filtration facilities. It is not designed for open flows (in the updated VSN 61-89 Construction Norms, these recommendations remained unchanged); therefore, it provides more substantiated results taking into account soils and coarse-grained material properties. Since filtering embankments are built in the soils prone to climate-induced variability, the geotextile material separating layers should be calculated taking into account the water-loss coefficient that significantly affects their ability to filter, especially in their frozen state. Practical significance: The proposed method of hydraulic and filtration calculation of filtering embankments will allow designing more adequate protective measures for eliminating erosion.