Logic Masters Deutschland e.V.

Shade some empty cells dark gray to create a single orthogonally connected canal. Numbered cells cannot be shaded as canals, and canal cells cannot form a 2x2 square anywhere in the grid. Each numbered cell indicates the total number of shaded canal cells connected vertically and horizontally (in a straight line) to that numbered cell.

In addition, each unshaded (i.e, non-canal) region must be colored entirely as a single color selected from red, green, or blue. The clues outside the grid indicate the number of orthogonally connected unshaded cells of the respective color(s) in that row or column, they can not be 0, and contiguous runs of same coloured cells have to be separated by at least one shaded cell. If clues outside the row/column are given, those are all the clues for that row/column, and they appear in the same color order as the unshaded regions in that row/column; rows/columns without clues may have any number of unshaded cells. Unshaded cells of different colors must not touch orthogonally (i.e, they must be separated by at least one canal cell). All numbered cells must be colored along with the other cells in their respective region. There can be different regions of the same color (there seems to be some confusion over this).

Penpa

This is the sequel to Cavino

If you haven't already, check out Dumediat's original Emergence which also has a visual example.

Answer check works when you draw green edges on the regions (makes no sense I know). I tried it with shading but then there's the risk of being congratulated when not all regions have been fully colored.