I have 6 samples of water quality parameters taken on a 10 km stretch downstream (Cooum River in Chennai), so it's basically the estuary.
The river discharge and flow is extremely low, therefore I assumed the current to be not an important factor.
Which interpolation method would make sense in this set up?
Since the number of sample points is extremely low I moved away from IDW.
At the moment I am considering Indicator Kriging, which was recommended for pollution data in general.