tailwater can also refer to a type of fishery. tailwater fisheries can be defined as tailrace fishing which occurs at the outflow from large dams, where the size of the reservoir creates a steep temperature gradient, with colder water stored at the bottom of the reservoir near the outlet. the constant cold-water flow provided by the reservoir's outflow, coupled with the generally silt-free nature of the outflow, creates ideal water conditions for cold-water fish such as trout in environments that ordinarily might not support a robust trout population. an example of this phenomenon is the fishery at lee's ferry on the colorado river in arizona.