How to interpolate values along a stream network

[BenjamenWetherill]

In ArcMap, is there a way to interpolate water quality values along a stream network?  I have values that were collected at stations in my stream network, and I would like to interpolate them between stations on connected streams.  I thought about using raster interpolation, but I don't want to interpolation to jump laterally across watersheds - just along the flow of water.  I would like to be able to use graduated coloring on the streams to show changes in water quality.

[SteveLynch · Accepted solution]

Have you looked at Spline With Barriers and Kernel Interpolation With Barriers

[BenjamenWetherill]

Thanks.  I will try these.

[BenjamenWetherill]

Spline with Barriers works perfectly!  If I draw a polygon barrier that follows the streams and separates lateral streams, and doesn't block direct lines between consecutive sampling points.  My license doesn't include Kernel with Barriers.

[DuncanHornby]

Does that make sense? If you are sampling pollutants as a measure of quality won't they have "diffused" or  "gone downstream" by the next day? Interpolating specific pollutants would imply some sort of static distribution I guess?

[BenjamenWetherill]

Yes, I would say it makes sense.  Rivers are not monolithic.  They receive pollutants at specific points and the pollutants get diluted or attenuated at other points.