Having recurring dreams lately of heavy rain turning my ditch into a rushing flooding river destroying things in it's path?

Perhaps there is something in your life that is out of your control and you fear it becoming too overwhelming. Also, if it has been raining a lot where you live that could have something to do with it. Try thinking about the surrounding areas in your life or what may be pressing on your heart lately and discern whether or not it may have some correlation.

Dream interpretation can be tricky. Don’t focus so much on symbols as much as how the dream made you feel.
In this case, maybe you feel anxious about something in your life that’s out of your control.

A fast rushing river is a destructive force. One that you cannot control. It's quite literally a force of nature. You feel like something in your life is being destroyed by something you cannot possibly control.