The problem is that roads surround the reservoir, so the toads have to face down cars and trucks to make it from their woods and backyard homes to the water. Here's a Google satellite image of the area for reference:
Here's a shot of one of the fearless little guys.
Toads weren't the only ones partying that night. We spotted this pickerel frog (Rana palustris) making the same trip (sorry for the off-kilter photo. They keep loading like this, dammit Blogger).