The Garonne Crossing

Getting to the River Lot involves leaving the Canal de Garonne at Buzet, travelling 4km down the River Baise and then descending onto the River Garonne for 4.5km, travelling downstream past the confluence of the River Lot to the ‘canalet’ that by-passes the last, shallow, 3km of river itself.

The Crossing (the passage or traverse onto, along and off, the Garonne) is not always available. When the river is to some degree in flood and flowing fast, is one example.

The converse is also the case. In periods of low rainfall – during the summer months – the river level drops, causing the obvious problem of lack of depth but also increasing current speed where the channel width becomes reduced. This is primarily where the River Lot enters, since there are gravel banks there, brought down by the river. Garonne levels are reduced further at these times because water abstraction from the river by agriculture (a significant factor) increases, compounding the problem.

There are various suggestions for tackling the problem including digging a deeper channel, creating a barrage downstream from the Lot canalet junction at Nicole to maintain depth but there are practical difficulties with both of these, plus the nature of the ecluse at Saint-Leger.  The most viable solution would be to create a completely new short branch canal between the Canal de Garonne and the river downstream from Nicole at a point where both waterways are very close to one another. That section of the Garonne maintains depth and navigability at times when the Baise-Lot section does not.

Garonne Pilots

First and foremost it should be noted that the Garonne river pilots are skilled and experienced and should be one’s first point of information about the ‘current situation’. They can be contacted on 06 08 02 32 15 (Didier Deslandes) but pilotage (and hence operation of the Buzet ecluse at Saint-Leger and the Lot canalet ecluse at Nicole) is only available, when conditions allow, all day on Mondays and Fridays and half days on Tuesdays and Thursdays. At other times it is unavailable.

The Vigicrue Website

Another vital source of information is the Vigicrues website, which provides mapped data about river levels, present and past, for the Garonne and all of its ‘feeder’ rivers joining from north and south. The Garonne itself rises in the Pyrenees. From the site one can see if levels are currently below, at or above ‘normal’ conditions. If they are significantly below then the prognosis is unfavourable. http://www.vigicrues.gouv.fr/niv_spc.php?idspc=15 and click on any waterway to see condition data.

The most significant monitoring stations for the Garonne Crossing are at Agen and La Magistère. See here for the combined 3-day graph. There are two useful pieces of information that can be obtained:

• When the graph level at Agen (upstream from St-Leger) is higher than -0.5 the crossing is probably feasible.
• If the line showing the La Magistère level is higher than Agen’s this indicates that additional water is travelling downstream. Agen’s and then St-Leger’s levels should rise in due course.

Otherwise, the place to get visual clues to the state of the river is actually at Saint-Leger (Baise) ecluse.

Indicator 1 – Level Marker

(Thanks to Robert Graham, capitain at Port Lalande for the following, which is the accurate method)

• Inspect the water level against the vertical level scale fixed to the upstream ecluse wall.
• Navigation should be possible between +116 above 0 (i.e datum) and -119 below it.
• Below -119 there is insufficient depth, above +116 there is too much water flowing.

Indicator 2 – Marker Posts / Channel Guides

Thanks to some intensive research over many weeks by Alan Robinson, we can also advise the following rule-of-thumb (click on images to enlarge) :-

Insufficient Depth Sufficient Depth 1. Look at the rings showing on the red (port hand) channel marker post. If you can see more than 4 red rings and 3½ white rings showing above the water level then there is insufficient depth.

Insufficient Depth Sufficient Depth 2. Look at the concrete channel guide immediately outside the ecluse gates. It has a chamfered top edge and a steel marker post at its end. If the river level is noticeably below the bottom line of the chamfer then there is insufficient depth.

The Garonne Crossing Itself

Private boats with experienced skippers and crew will take charge of their own passage. (Hire boats are skippered by a pilot, their occupants being transported separately to Nicole by boat or vehicle. Passengers are not allowed on towed/pushed boats. )

St-Leger Ecluse (click to enlarge images) Going downstream, the pilot boat will precede and indicate the safe channel, particularly at the point of confluence with the River Lot where it is restricted by gravel banks and runs faster. Towards Nicole the pilot will go ahead, moor up on the outside pontoon and prepare the ecluse.

Nicole River Pontoon Nicole Ecluse

From the skipper’s point of view the turn into the ecluse entrance can be tricky. The river current tends to carry the boat sideways downstream towards the boulders retaining the bank outside the ecluse and there are also significant back-eddies to spoil the approach. If in doubt, do what the pilots do, which is to turn downstream from the ecluse, heading directly into the current, thus getting lots of steerage and control.

Upstream Turn Push Boat

Going upstream, one will often need the assistance of the pilots to tow or (more usually) push. One pilot will usually accompany the skipper on board the boat. The pusher boat is adequately powerful to provide the additional force that many smaller boats need to overcome the downstream current. Once beyond the road bridge at Saint-Leger conditions become much easier, but the turn into the ecluse there still needs care.

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