You can easily make the tent awning watertight again with a good impregnating agent, such as Sprayhood & Tent Protector. This impregnating agent is highly suited for use on most tent awnings made by all the well-known bands, such as Dorema, Ten Cate, etc.
We developed Sprayhood & Tent Protector especially for impregnating camping tents, boat covers, window awnings and catering umbrellas. We have been using it for years to impregnate this type of tent canvas and make it watertight.
More about impregnating tents: http://www.ultramar.nl/tents/impregnating-tents/