Mann - Kendall test on hydrology autocorellated data in R

i have a problem on time series analysis. i want to check if there is a trend in my time series. i am completly new to ts analysis so i have no idea how to do this. i just know that i got to go with Mann - Kendall test. my data is autocorellated and looks like this:

Date          flow
01.11.2005    0,038
02.11.2005    0,045
03.11.2005    0,051
04.11.2005    0,05
05.11.2005    0,05
06.11.2005    0,05
07.11.2005    0,05
08.11.2005    0,05
09.11.2005    0,05
10.11.2005    0,05
11.11.2005    0,038
12.11.2005    0,038
13.11.2005    0,038
14.11.2005    0,038
15.11.2005    0,038
16.11.2005    0,049
17.11.2005    0,049
18.11.2005    0,048
19.11.2005    0,048
20.11.2005    0,048
21.11.2005    0,048
22.11.2005    0,048
23.11.2005    0,037