It is best to have a menege for competition training. This gives the horse and rider a chance to concentrate on their jumping or dressage skills. If a person has to travel or use several arenas, getting to know the footing takes time. Competition riders know that every day counts when training and they train as much as possible. Horse and rider will become familiar with the layout and feel of an arena they use all the time. They do not need extra time to learn where the ground might be softer or dip a bit.
When building a training arena, it is important to ensure the ground is prepared first. Leveling the ground is the first step. It must be filled and then tamped to ensure it will not sink. After leveling, installing a proper drainage system is important. Without proper drainage, the arena will be muddy and mushy. This is bad for riding because the horse may be hurt if the ground dips even a little.
Membranes are used as part of the drainage system. There is one membrane below the drainage pipes. This is to ensure water not captured by the system will not rise into the top level and soften the ground. There is a second membrane above the drainage system. This membrane siphons water out of the surface and directs it into the drainage pipes. This is necessary to keep the ground hard enough for riding after a rainstorm.
Above the top layer of membrane is a layer of silica sand. While commercially available from many sources, it must be sand that is not taken from areas where clay mining is done. Particles of clay mixed in with the silica sand will eventually clog the membrane and hamper drainage. Sand may be the top layer, or other surfaces can be used. This choice depends on the type of training expected to take place in the arena.