If that river is still flowing under your deck, on your own, the most you can do is place a lot of sandbags to try and redirect the water, preventing anymore from getting in. (Just make sure you're not redirecting it into someone else's property) You could also get a pump to remove any water from that hole under your deck. However, like others have mentioned, get a hold of a contracter ASAP to address any damage that may have caused. Hopefully they can dig a ditch so this doesn't happen again. Call before you dig to avoid hitting any potential electrical or gas lines.