A hydraulic project is the construction or performance of work that will use, divert, obstruct, or change the natural flow or bed of any of the salt or fresh waters of the state. Unless otherwise provided, any person who wants to conduct a hydraulic project must get a construction permit called the hydraulic project approval (HPA) from the department. The purpose of the HPA is to ensure that construction or performance of work is done in a manner that protects fish life. This chapter establishes the rules for the department's HPA authority (chapter 77.55 RCW).