I'm playing Fortress mode, using the Masterwork mod (though the mod isn't terribly important to the question).
During Spring of my first year, the caravan had camels pulling them, and one of them got knocked off a high bridge into water. The fortress is now about ten years old, and by the time I had interest (or resources) to deal with them, they numbered about 40. Now they are milling around, breeding, chewing up river grass as fast as they can chew up my FPS. I want them dead.
I have tried building a ledge over the river so that my military can shoot them. They tend to avoid the area. The river has only one access point, being down in a deep gorge, so 'building a ledge all the way to them' is feasible, but not very practical.
I have tried to build a fish farm, tapping into the river with channels filled with cages. This trapped only one. Five of them jumped up onto the first cage and managed to leap out of the channel without getting caught, because I had wild camels all over my fish farm, and I had to have the military mop them up. I have since expanded the fish farm, but they're not pathing in.
After all of these efforts, 33 of the two-humpers remain.
1) Are there any suggestions on how I might exterminate the pest that is the elusive water camel once and for all?
2) I know I can dam up my river - but the location is important because of two feeder waterfalls. I'm very leery of this solution because of past Water Horrors. How can I tell where my river is exiting the map? Will damming my river cause flooding because of the feeder falls?