layer=-1 doesn't make sense here - the things that are above it are already layer=1.

The more normal way of tagging these is as an "intermittent canal" See https://www.openstreetmap.org/way/1018789407 for an example south of the border. This is the only usage=spillway that isn't also something else in IE/UK.

It's odd, but surely waterway=ditch is the best way to map these.

man_made=pumping_station is the far more common way of tagging these: https://taginfo.openstreetmap.org/search?q=pumping_station#values

Based on the imagery, these are area features

Based on the imagery, these are area features

Filled in area of moat from OSSV / OS OM Local

Someone's surveyed the bit in between, so fill in the gap I left.

The usual tagging for these now is man_made.

Based on previous note, this is a man_made=pumping_station

Removed duplicate Navigation Inn

Based on the aerial imagery, this looks like a building.

There is a separate sidewalk here - it has already been mapped.

Cliff is a bit of a stretch here; "area waterfall" (of which there are a couple of others) is less so.

Make clear that this is a linear not an area feature

Removed "area" waterway=ditch that was a duplicate of https://www.openstreetmap.org/way/943540159

This lock gate has been mapped as an area

This lock gate has been mapped as an area

Likewise this one

It doesn't make sense to map this as an area, but linear does make sense.