This page lists some simple but effective quality control checks you should always do after you have processed your network with any river network processing tool.

Warning Always run your network through all the quality controls that RivEX provides before you attempt the network attributing tools. 

Construct the river mouths and sources of your network and display them on top of your network.  A mouth should not occur within the network as indicated by the green circle in the image. 

Equally sources should not occur within the network, unless it is occurring at a saddle and even then you will want to remove them.

Mouth in network

With Strahler stream order, no polyline should have a zero order, so do a simple query on the Strahler field searching for all values with a zero value.  Equally see what the highest stream order value is.  If your sequence goes 1st, 2nd, 3rd, 4th, 5th, 8th then something strange has definitely happened! 

Zero order example

Colour code your river network and just look at it! It should follow a logical colour change as you go from source to mouth. In the image to the right the 3 arrows indicate illogical changes in colour when the network is colour coded by Strahler order. These would indicate there are polylines flowing in an uphill direction that need flipping.

    1. A third order stream (green) feeds into a first order stream (dark blue)
    2. A third order (green) and fourth order (red) come together and become a first order stream (dark blue)
    3. Two second order streams (light blue) come together and remain second order (light blue)

If this was a large river network and you were just looking at the values in the attribute table then you will have missed these errors.

Bad network

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