Use of convex and concave concepts to estimate the sediment volumes in a main irrigation canal of Southern Slovakia

One of three main irrigation canals of Southern Slovakia – Chotárny canal. This paper investigated and assessed sediment deposits at the bottom and slopes of the canal. The analysis was based on a reconnessaince survey, field measurements of sediments in the canal and other relevant information from the years 1993, 2012, 2015 and 2018. Traditional sediment volume calculations were compared with the use of convex/concave trendlines of sediment distribution capturing the silting situation in the canal, and a new polynomial equation for the sediment thicknesses. The total sediment amount ranged from 109,272 m 3 to 166,293 m 3 over 19 years of field measurements and observations from 1993 to 2018. The study revealed the following differences between the amount of sediments computed traditionally and the procedure presented in the paper: 6.28% in 1993, + 2,84% in 2012, + 0.34% in 2015 and 0.46% in 2018. Upper and lower confidence interval limits were computed using a 95% confidence level. Future recommendations include, but are not limited to, computation of soil loss in the drainage area, measurement techniques to ensure high-level precision, and elimination of the human factor. Preparation of specific protocols for monitoring frequency in the canal network in cooperation with the canal network owner and government agencies is also recommended. • Field measurements of sediment deposition in irrigation canal in Southern Slovakia is performed. • Data collected over the period of 25 years is assessed statistically. • Convex/Concave courves concept is used to assess the data. • Antiderivative function to estimate sediment volume amounts in irrigation canal is derived. • Polynomial equation to predict future sediment depositions in irrigation canal is offered.