This article provides an analysis and recommendations of the factors that lead to the loss of water as a result of filtration in uncoated canals, rising groundwater levels, deterioration of land reclamation, reduction of canal efficiency coefficient. According to the project data, the part of the Greater Fergana canal from PK-930 to PK-1500 + 10 was built in the type of semi-excavated and natural canal. From PK-930 to PK-1040, the ground level is almost equal to the bottom water level, and the volume of soil discharged in this part of the canal is greater than in other parts. The canal is in the form of a trapezoid and has now changed its shape slightly as a result of a small amount of sedimentation and erosion. In uncoated canals and irrigation systems, there are a number of connections to perform the basic filtration calculation. These bonds are obtained according to Darcy’s law, filtration for homogeneous and isotropic soils. Using the available data, it is possible to determine the depression curve in canals and irrigation systems for all cases, the points that form its curvature, and the filtration rate that occurs in it. It consists of determining the filtration rate (q) of the system at a length of 1 pogm and the filtration coefficient (k) of the soil.