Waterways in the United Kingdom

Mainland Britain has 3,000 to 4,000 miles of waterways that are commonly considered "navigable" by powered boats. Added to this are numerous derelict canals which can still be traced on the ground, and also many, many more miles of canoeable rivers. Many of the derelict canals or lost river navigations are active restoration projects with over 600 miles (>960km) having already been restored to navigation since the major restoration movement started in the 1960's.

OpenStreetMap began in London, and the River Thames flowing through London was one of the first places where we pondered the challenge of mapping large (also tidal) rivers in a way which allowed software to render it properly. The tidal section of the Thames was initially brought in by the coastline imports, and then traced from Landsat.

OSM-based waterway maps

• OpenRiverBoatMap is a European map but may not render UK waterways correctly due to tagging differences [NB OpenRiverBoatMap seems to have been offline for a while as of May 2021 and may not be being maintained any more]

What (and how) to map

The following tags are those in majority use in UK waterway mapping at the present time, as confirmed by Taginfo.

Waterways

Navigable waterways are mapped as single ways like this:

• waterway=canal
• name=Trent & Mersey Canal (use '&', not 'and')

or

• waterway=river
• name=River Thames
• boat=yes (important - after all, most rivers aren't navigable)

For more details see waterway access tagging:

• motorboat=yes is implied by modern UK use.
• canoe=yes is useful for all paddlecraft users if confident it's allowed, practical year-round, and often applies to many more rivers and waterway=derelict_canals that aren't navigable by larger boats. (You could change known-good sections to waterway=canal, boat=no, canoe=yes)
  • Take great care not to map river sections immediately above and below weirs as canoe=yes; these can be extremely dangerous and have resulted in multiple drowning incidents. Many weirs are hidden in satellite imagery, abandoned at the site of historic watermills. Large scale historic maps can be useful to identify these, followed by a survey to confirm today's ground truth. Then you can tag any footway around the hazard with canoe=portage. If in doubt or you don't have local knowledge of safe paddlecraft conditions, don't map it.

For a tidal river, add

• tidal=yes

The direction of the way should be downstream. It should be drawn to follow the centre of the navigable channel.

If you like, you can create a more detailed map by additionally drawing the outline of the waterway, as natural=water + water=river. But you do still need to add the centreline as above for routing purposes - the outline is less important.

Relations

Please check UK Waterway Relations, and create a new Relation:waterway if none exists for the river or canal you are mapping. Then add it to the UK Waterway Relations list. (Note, this requires an OSM wiki account, but is very simple to do)

Towpaths

Towpaths are mapped as footways or cycleways as usual, depending on their construction:

• highway=footway
• towpath=yes

or

• highway=cycleway
• towpath=yes

Many towpaths are nominally open to bikes, but haven't been adapted for use by them (for example, unimproved rural towpaths). Map these as highway=footway, bicycle=yes, towpath=yes to reflect the fact they're really just footways on which bikes are allowed.

The surface=* tag is very useful in telling people what sort of towpath to expect. Use one of the most commonly found values.

smoothness=* is also strongly beneficial for routing engines, as it demonstrates whether a towpath is suitable for different kinds of wheelchairs, road bikes, MTB, etc. StreetComplete is very useful to survey this on the go.

Locks

Each lock should be a separate way, mapped like this:

• waterway=canal
• name=Trent & Mersey Canal
• lock=yes
• lock_name=Branston Lock
• lock_ref=8 (the number of the lock, if it has one)
• lock:leave_empty=yes (if the lock is to be left empty. This is often the case where livestock have access to the water, or for turf locks)

The first node should be the top gates, the second and last node the bottom gates: in other words, it points downstream.

Each lock gate node should also be given a tag:

• waterway=lock_gate

Staircase locks can therefore be plotted simply by sharing lock-gate nodes.

For large locks, you might again want to add a waterway=riverbank polygon - Eastham Lock certainly needs one!

Lock landings

Lock landings should be a separate way on top of the canal bank, mapped like this:

• mooring=lock_landing

Bridges

Just like any other bridge in OSM, but add a bridge:name=* and bridge:ref=* tag:

• highway=tertiary
• name=Dallow Lane (the road name as usual, not the bridge name)
• bridge=yes
• layer=1
• bridge:name=Dallow Lane Bridge (the name of the bridge)
• bridge:ref=32A (the bridge number)

If it's a private accommodation bridge over a rural canal, just tag it as a private track:

• highway=track
• access=private
• bridge=yes etc.

If it's a lift or swing bridge:

• bridge:movable=swing or
• bridge:movable=lift

Bridge landings

Bridge landings should be a separate way on top of the canal bank, mapped like this:

• mooring=bridge_landing

Tunnels

Same idea:

• waterway=canal
• name=Trent & Mersey Canal
• tunnel=yes
• layer=-1
• tunnel:name=Harecastle Tunnel
• maxwidth=7'0" (and maxheight for headroom, etc.)

Derelict waterways

Derelict canals are traditionally tagged in the UK as:

• waterway=derelict_canal
• name=Thames & Severn Canal

Unnavigable rivers can, of course, be tagged as:

• waterway=river
• boat=no

Dimensions

You can tag the limiting dimensions of waterways, locks, or even winding holes:

• maxlength=72'0"
• maxwidth=7'0"

Note that, on a bridge, the maximum length/width refers to traffic using the bridge itself (probably a road). So if you want to tag the maximum width or height of the waterway passing underneath, put that on the waterway, not the bridge.

Boating facilities

• Water points: a node on the bank with waterway=water_point
• Winding holes: a node on the waterway with waterway=turning_point
• Elsan disposal amenity=sanitary_dump_station with sanitary_dump_station:basin=yes (see Feature page)
• Pump out: amenity=sanitary_dump_station with sanitary_dump_station:pump-out=yes (see Feature page)
• Fuel: waterway=fuel with fuel:diesel=yes

• (to add: showers, etc. etc.)

Moorings and marinas

Moorings can be tagged two ways:

1. Add a point and tag mooring=yes with maxstay=48 hours, 7 days; etc.
2. If you know the full extent of the mooring, add a line over the appropriate part of the canal bank and tag as in 1.

(As suggested here: http://canalmap.net/editing-openstreetmap ^{[ dead link ]})

Mooring types include:

• Armco: mooring:type=steel_barrier

A full list at: Key:mooring:type.

Marinas:

• Tag an area with leisure=marina and landuse=basin.

Further tagging information

See Key:waterway, Key:boat, Key:lock (and waterway=lock_gate on individual nodes), Key:leisure, Key:mooring and Key:tunnel. Key:historic can also be relevant to abandoned canals.

See Also

• UK Waterway Relations