I played Old Marsh in the FL Mid-Am last year.
There is a lot of water, but there is also some room. If the wind blows or you are not playing well, it can become an issue. I would also think that it could be quite difficult for a higher handicap player (I could be wrong as I did not pay much attention to forward tees).
*when I say water, it might be water or a marsh
1 - Shorter par 4 with water all down the left, but really shouldn't be in play. There is also a bunker on the left to keep some balls from bouning into the hazard.
2 - Par 5 with tee shot over water and water / OB on both sides, but probably 100 yards of room. I don't recall water on the second or near the green.
3 - mid/long par 3 with water all down the left. Definitely in play.
4 - Medium par 4 with OB marsh left and water near the green. There is a forced carry to the fairway, but none of the hazards are really in play.
5 - Short par 4 with water all down the right and around the green. I really didn't like this hole. There is a huge mound infront of the green, and there is no play you can hit your drive to be able to see any part of the green. They had to have a spotter by the green because so many balls would land on the green and roll into the water. You had no idea where you were hitting it.
6 - Long par 4 with water all down the right and OB left. Really tough hole, and the water is in play on every shot.
7 - Medium par 5 with a carry over water to a wide fairway and water all down the right. Lots of room, but water is in play if you go for it in 2 or there is a back right pin.
8 - short par 3 with water on the right. I don't recall it really being in play.
9 - Long par 4 with a carry to the fairway and water all the way up the left. Second shot is a brute, and the green sits next to the water.
10 - Short par 4 with water left and right, but not really in play. Less than driver and a wedge. There is a tree in the fairway that makes you flirt with the water on the left for a good look at some pins.
11 - Medium par 4 with a long carry to fairway. You can't really see the fairway from the tee, and just blast it out over a marsh. In reality, there is a lot of room.
12 - Short par 5 with water on both sides. Very much in play on your second/third.
13 - Med/Long par 4 with OB left and water right. A very tight, and uncomfortable drive. I found it one of the hardest holes on the course.
14 - Med/long par 3 with water on both sides, but only really in play on the left.
15 - Long or Short par 4. There are two tees on this hole. From the back, it is a long par 4 with a long carry to the fairway. From the other tee, there really isn't any water on the hole.
16 - med par 3 with water to the left. Not too much in play, but a few will find it.
17 - par 5. Water on both sides off the tee shot, water on both sides of the lay-up althought there is a lot of room left, but you need to have hit a good drive and hit a lot of club to get to that area. I think there is some water right of the green, but not really a factor.
18 - Long par 4 with OB left and water right and a carry to the fairway. Basically the mirror of 9, and the water is really in play near the green. Tough hole, especially when playing into the wind.
I liked Old Marsh, and on my first play didn't really notice a lot of the water. During the event, I didn't play well, and it was constantly in my mind. Watching some of the members on the range during my practice round, it bet they sell a lot of balls in the shop. I have played a lot of other courses in FL that have less water, but it feels more prominent. Old Marsh is a marsh, and the area around the holes that doesn't have homes is just marsh. I only felt pinched a couple of times (7 and 13), but twice in a round is fine with me. I find it a place that I would like to visit every once in a while, but it could be brutal to play everyday. You really can't get away with anything on a bad day.