Ok, So I assume you got the arrow back? Or did it break and you only got some of it back? How far did the shot penetrate? Sounds like you hit him sqaure in the shoulder. I would check cover near the spring. This would be a good place to start. More than likely,
he probably laid up in heavy cover after the shot if not pushed too hard. Even if he was pushed and is/was still alive, he'll probably head back to the water to bed/drink. He won't want to move too far to get the water, so he's probably bedded near the spring. If you don't find him, you may find where he bedded (blood).