"Like all search dogs, cadaver dogs go through extensive training before they can become certified and operational. Cadaver dogs are first trained to recognize a wide spectrum of odors associated with human remains, depending on their specific use. Cadaver dogs for use in a disaster situation focus on more recent decomposition odors, while cadaver dogs that work with law enforcement are also trained to recognize older decomposition odors and smaller odor sources. Only actual human remains are used to train the dogs, no pseudo scent is used in the training process. All K-9s are first taught to give a trained final response or indication upon detection of the odor. They are taught to only give this response when they locate the strongest source of the odor. A large amount of time is spent on making sure that the indication is solid before the K-9 is ever taught to actually search for the odor in a scenario-based problem. Cadaver dogs that are trained in water recovery are taught to give this final indication while working from a boat on a body of water." -from
http://www.illinoissearchdogs.org/capabilities/cadaver_dogs.shtml
So, if the dogs only alert at the "strongest" source of the odor, why are they alerting all over the place on the reservoir. This suggests a couple of things to me. Someone (I think Emma) mentioned the reservoir being constructed on native american burial grounds possibly OR the source of the scent is from a number of sources OR the single source of the the odor is in pieces. If it's the later, then somewhere there is a messy crime scene.