N.H. Rev. Stat. Ann. § 482:91
I. Upon the recommendation of the department, the governor and council are authorized, in the name of and on behalf of the state, to enter into agreements or compacts with any one or more of the New England states or an adjoining country as the governor and council may deem to be in the best interests of this state. Such agreements and compacts shall be for the purposes of promoting health, welfare and public safety by conserving and regulating the waters in all rivers or streams whose drainage basins or any portion of a drainage basin lie within this state as to:
Source. 1989, 339:1. 1996, 228:106, eff. July 1, 1996.