To ensure high-quality and continuous operation of dredging works, depth measurements are performed with the required frequency. A color array of depths, bottom profile, gradient of slope are provided on-line in digital form. CREDO and QINSy software is used to calculate dredging. The volumes are calculated with an accuracy of one m3 and the results are considered satisfactory if the discrepancy between the calculations for the two programs is not more than one or two percent.