Comparison of Mann–Kendall and innovative trend method for water quality parameters of the Kizilirmak River, Turkey

Abstract

Summary Low, medium and high values of a parameter are very important issues in climatological, meteorological and hydrological events. Moreover these values are used to decide various design parameters based on scientific aspects and real applications everywhere in the world. With this concept, a new trend method recently proposed by Sen was used for water parameters, pH, T, EC, Na+, K+, CO 3 - 2 , HCO 3 - , Cl−, SO 4 - 2 , B+3 and Q recorded at five different stations (station numbers and locations: 1535-Sogutluhan (Sivas), 1501-Yamula (Kayseri), 1546-Tuzkoy (Kayseri), 1503-Yahsihan (Kirsehir), and 1533-Inozu (Samsun)) selected from the Kizilirmak River in Turkey. Low, medium and high values of the parameters were graphically evaluated with this method. For comparison purposes, the Mann–Kendall trend test was also applied to the same data. Differences of the two trend tests were also emphasised. It was found that the Sen trend test compared with the MK trend test had several advantages. The results also revealed that the Sen trend test could be successfully used for trend analysis of water parameters especially in terms of evaluation of low, medium and high values of data.