IF your arena is outdoor, it may have limited use during the winter months depending on the type of surface you have, but regardless of surface type, they all require maintenance.
Surface
Assuming your arena is for multipurpose use, for good footing you would need a base layer of 4-6 inches: if regularly jumping it may require to be as deep as 10 inches. It’s best to get advice from an expert for your exact needs. Good footing is paramount for safety and support to encourage a horse to move forward with energy and elasticity.
Harrowing is necessary to maintain the surface of most arenas but is often overlooked. Harrow an arena slowly in different directions, starting with the short width followed by the long width: harrowing in one direction may cause high and low spots. If you don’t have a harrow, your arena should be raked by hand or a wooden palette on a tow bar can work too! Pay particular attention to the outside track as ruts can be formed here depending on the level of use and type of use. It is important to ensure all build up is evenly harrowed or raked to make sure the surface remains even for good footing. Without this method, it can result in hard footing associated with joint and ligament problems.
A good watering programme will support arena maintenance and counteract against hard footing.
Daily maintenance of your arena should include picking up any stones that have surfaced, removing weeds and ensuring all horse droppings are removed.
Drainage
In terms of drainage, an arena should ideally be located on dry, well-draining ground. If your arena has become flooded or developed surface pools of water, the main reason for this is poor drainage, over use, or an uneven surface due to lack of regular maintenance. Working wet surfaces with a harrow usually speeds up the drying process.
If drainage problems continue it could be of benefit to cut out a shallow ditch around the perimeter of the arena. Depending on the surrounding ground type and angle of the drain, the rainwater collected in the ditch can flow directly onto lower ground or can be drained away.
If your arena continues to be too wet, slippery, or too muddy, this could be down to poor original design, an insufficient base or inappropriate surface material. Cutting corners or going for the cheapest option can result in more expense in the long run, not to mention harm to your horses.