I like the concept, but I have a few suggestions:

• Maybe make the green a bit darker. I get that you're going for grass and a river, but that's conveyed with any green, and I think a dark green would go a lot better with the lighter blue.
• As another commenter mentioned, the river would be better as a simple diagonal stripe. You don't need a complicated river shape to convey a river.
• This may be limited by your drawing skill, but I think the emblem should be more complex. Right now, it's in this area where it's not simple enough (i.e., it's not just a flat, one-color shield) to match with the rest of the flag but it's not complex enough to really feel like an emblem. It stands out but doesn't quite have the complexity to warrant it, if that makes any sense.
• The emblem might be better off in the middle, left, or upper left. Symbols on flags tend to go there instead of on the right, where it'll be flapping in the wind more.