N.H. Rev. Stat. Ann. § 210:9
II. Notwithstanding paragraph I or any other provision of law or rule, a landowner, the landowner's agent, or any town or municipal or state official or employee, may destroy beaver, remove beaver dams, or install one or more flow devices on property under their control to protect property, public highways, or bridges from damage or submersion. The landowner or property owner shall be responsible for maintaining the flow device. Complete or partial dam removal or the installation or removal of a flow device shall be allowed without a permit under RSA 482-A if machinery does not enter the water and filling or dredging in or adjacent to surface water, wetlands, or their banks does not occur and shall be done in a gradual manner that does not allow a sudden release of impounded water so as to cause erosion, siltation, or a safety hazard downstream.
II-a. For purposes of paragraph II, the term "flow device" means one or more fence structures or other combination of fencing and piping used to discourage beaver damming, maintain water flow through an existing beaver dam, or minimize the risk of flooding by preventing the further impoundment of water behind a beaver dam.
Source. 1939, 81:2. RL 244:10. 1943, 64:3. RSA 210:9. 1967, 441:3. 1988, 79:1. 1996, 228:42. 2009, 257:1, eff. Sept. 14, 2009. 2019, 125:1, eff. Aug. 24, 2019.