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River Medway Hazards Guide

Whilst the non tidal section of the River Medway is a very flat slow moving river, it is not without it’s hazards. Some of these may be obvious, others less so.

This guide is written very much for novices and those who have little or no experience of paddling on a river like the Medway.

Orange Booms

These are not usually a hazard in themselves but their presence does generally indicate there are potential hazards close by. As a general rule stay well clear of these and do not go inside the boomed off areas.


A sluice is like a gate that is designed to hold water back and let water through when required. They are used to control water levels on the river. The sluices on the river lift at various times but more so after periods of rainfall.

The water level above the sluice is usually higher than below.

When a sluice opens there are 2 main things to be aware of:

Above the sluice the water will start to be pulled towards the sluice. There will usually be orange booms sectioning off the area above a sluice and you should keep well clear of these particularly if you notice any discernable flow towards the sluice as this is a clear indicator that the sluice is open. The more the sluice opens the greater the pull will become.

What happens below a sluice very much depends on the structure below. Some sluices release water causing strong currents that flow away from the sluice very fast creating a “white water” effect. In other places the structure can cause the water that is released to re-circulate back towards the sluice (towback). Where there are walls both sides of this type of feature it is particularly dangerous (see below)

The area below a sluice will not necessarily be protected by orange booms.

Both of these represent significant hazards so stay well clear of them.


The weirs on the Medway are usually sloping concrete structures with a very shallow amount of water running down the slopes. These all have orange booms protecting the area at the top of the weirs so they should be very evident when approaching them.

The area at the bottom of these sloping weirs can also be hazardous in some conditions as water can re-circulate here making it difficult for a boat or people to paddle or swim away (in the event of a capsize). These areas will not necessarily be protected by orange booms.

Canoe Passes

There are now 7 canoe passes on the river between Tonbridge and Teston. These are great fun and can add plenty of excitement to a trip.

It may seem strange to include these as hazards but this is just to ensure that appropriate precautions are taken where required. These are all man made structures, often surrounded by hard surfaces so it may be sensible to consider wearing helmets on some of the more challenging passes or where you have youngsters on board.

Always make sure a pass is clear before you go down it. After periods of heavy rainfall debris such as tree branches can sometimes get stuck around these structures.Also if you are in a group make sure each person clears the pass successfully before the next person descends.

Some passes such as Sluice Weir exit quite close to the weir and sluice which means the general area below can be quite challenging if the sluice is releasing. Have a look before you go down the canoe pass and make sure you are comfortable with the conditions below.

Strong flows

Aside from the currents referred to around the weirs and sluices the Medway is generally a very safe river. However following periods of heavy rainfall the flow on the river can increase. On these occasions the Environment Agency will usually put up Strong Flow Warnings at the various canoe access points. The canoe chutes are also usually closed at these times.


Currents can form around locks when these are being operated by other boat users. Keep clear of lock gates while they are being operated. Going through the locks with other powered boats may seem like a good idea but it is not without its risks and depending on whether you are going up or down river there are positions in the lock where it could be hazardous when the lock empties/fills. Other boat users may be able to advise although they may be novices themselves!

Motor boats

The river is very popular with motorised pleasure craft. Most are very considerate to paddlers but it’s not unusual to go around a bend in the river and suddenly find a motor cruiser coming towards you. Larger boats also create a wash (a wave effect) so be prepared for this when they pass you.


The river is very well maintained by the Environment Agency but there are some areas where there are low overhanging trees along the river bank. Trees have a habit of capsizing paddlers so try to keep well clear of these areas.

Submerged rocks

The Medway is not known for it’s rocks! However in some locations such as the weir pool below Sluice Weir there are a number of submerged rocks.

Weil's disease/Leptospirosis

A condition that develops following contact with urine from rats, rodents, foxes and other wild animals. Paddlers can come into contact as water washes from the land into rivers following periods of rainfall. Ensure you wash your hands or use hand gel prior to eating or drinking.

While cases are rare in the UK it does happen and can be very serious if not treated so is something paddlers need to be aware of. Symptoms are flu like and usually occur within a couple of days of paddling.

Giant Hogweed

A plant that has been identified in several locations along the Medway. Coming into contact with it causes painful blistering and severe skin irritation.

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