Hydra 2 represents a significant upgrade and extension to the HydrA software developed by the former Institute of Hydrology. The system estimates the annual power that can be generated by a hydropower scheme for a variety of turbine configurations. Hydra 2 methods encompass contemporary turbine envelopes and efficiency curves and enables penstock head-losses to be estimated. Variable environmental flow conditions can be simulated, consistent with trends in UK regulation.

Hydra 2 enables flexible input of flow duration curve data from any source. It can also be used in conjunction with WHS software products CatchmentsUK (to define contributing catchment areas) and LowFlows 2 (to provide estimates of the flow regime at ungauged catchments).

The licence is controlled by a USB dongle and is licenced for one concurrent run. It may be installed on an unlimited number of computers in one office.