How to make a site marker

The first survey of a site doesn't begin in the water, but on firm ground. A prospective site must be inspected first from shore, so that a likely spot can be identified and safe means of entry and exit determined.

This can entail a lot of walking along lake shores and river banks. Once you have found a spot that you think is worth a dive, you have to be able to return to it with your gear. The challenge is, can you remember exactly where it is when you come back again? One way is to use a site marker. This is a biodegradable indicator which you can make yourself on the spot, and hang from a tree or bush so you recognise it when you come back.

To make a site marker, you'll need about half a dozen reasonably straight twigs. One of them must be long, a couple of feet or so, and quite flexible so it can be bent into a ring. The others only need to be about 7 or 8 inches long. Their flexibility is less important, but they do need to be quite straight.

Getting a long, straight, and flexible twig isn't easy. Chances are that the loose twigs lying around will be dry and brittle and they just won't bend enough without breaking, though if straight enough they can be used for the shorter lengths. Fortunately a means to create a flexible ring is usually at hand. The trees beside a river will send roots out through the bank. Some will penetrate the bank again, but others won't. These roots are flexible living wood, but they are only connected at one end and are not supplying nutrients to the tree, nor are they binding the soil together. One of these can be cut with minimal impediment caused.

Assembly is simple:

• Bend the long flexible twig into a ring and bind it firm, using grass or a piece of twine if you have it.

• Next lay the shorter twigs across the diameter of the ring.

• By putting them on opposite sides and feeding one beneath another, they can often be held in place using nothing but their own pressure.

• Three twigs is usually enough to keep the marker in shape; get them to intersect at the centre, like a six-spoked cartwheel.

• Other more elaborate forms can be made and the twigs bound if necessary using more grass or twine.