Sepia is a colour, a hue, a tone or a dye. Either way it is classified as Black and White for the purposes of photography.
Sepia comes from a Cuttlefish, it is the dye they squirt out when in danger similar to an Octopus or a Squid. The colour and name of the fish is also Sepia, like Sepia Apama, the largest of the species.
As a photographer you should consider sepia a variant tone of black and white.
For me is represents the turn of the last century or late 19th. It is a hue used in London and the Wild West for portraiture photography. So I used it below to represent a Victorian Park.
The pigeons are representatives of the city, and use these areas to rest or feed.
The final part is the water. Many of these parks contain water and were a source of Enjoyment as well as calm.