Section 217.84 - Mitigation requirements(a) When conducting the activities identified in § 217.80(a) , the mitigation measures contained in any LOA issued under §§ 216.106 of this chapter and §§ 217.86 or 217.87 must be implemented. These mitigation measures include but are not limited to: (1) A copy of any issued LOA must be in the possession of the Navy, its designees, and work crew personnel operating under the authority of the issued LOA;(2) The Navy must follow mitigation procedures as described in § 217.84 . Protected Species Observers (PSO) must monitor designated harassment zones described in the LOA to the maximum extent practicable based on daily visibility conditions.(3) The Navy must ensure that construction supervisors and crews, the PSO team, and relevant Navy staff are trained prior to the start of construction activity subject to this rule, so that responsibilities, communication procedures, monitoring protocols, and operational procedures are clearly understood. New personnel joining during the project must be trained prior to commencing work;(4) The Navy must avoid direct physical interaction with marine mammals during construction activity. If a marine mammal comes within 10 m of such activity, operations must cease and vessels must reduce speed to the minimum level required to maintain steerage and safe working conditions, as necessary, to avoid direct physical interaction;(5) For all pile driving activity, the Navy must implement shutdown zones with radial distances as identified in a LOA issued under § 216.106 of this chapter and §§ 217.86 or 217.87 . If a marine mammal comes within or approaches the shutdown zone, pile driving activity must cease;(6) The Navy must shut down in-water activities when cetaceans are observed approaching or within any harassment zone;(7) The Navy must use soft start techniques when impact pile driving. Soft start requires an initial set of three strikes from the hammer at reduced energy, followed by a 30-second waiting period. Then two subsequent reduced-energy strike sets would occur. A soft start must be implemented at the start of each day's impact pile driving and at any time following cessation of impact pile driving for a period of 30 minutes or longer;(8) The Navy must employ bubble curtain systems during impact driving of 36-in steel piles except under conditions where the water depth is less than 0.67 meters (2 feet) in depth. Bubble curtains must meet the following requirements; (i) The bubble curtain must distribute air bubbles around 100 percent of the piling perimeter for the full depth of the water column;(ii) The lowest bubble ring must be in contact with the mudline and/or rock bottom for the full circumference of the ring, and the weights attached to the bottom ring shall ensure 100 percent mudline and/or rock bottom contact. No parts of the ring or other objects shall prevent full mudline and/or rock bottom contact; and(iii) The bubble curtain must be operated such that there is equal balancing of air flow to all bubblers;(9) The Navy must deploy PSOs as indicated in its Marine Mammal Monitoring Plan that has been approved by NMFS;(10) For all pile driving activities, land-based PSOs must be stationed at the best vantage points practicable to monitor for marine mammals and implement shutdown/delay procedures. At least one vessel-based PSO must be employed when practicable. Additional PSOs must be added if warranted by site conditions and/or the level of marine mammal activity in the area;(11) Monitoring must take place from 30 minutes prior to initiation of pile driving activity (i.e., pre-start clearance monitoring) through 30 minutes post-completion of pile driving activity. Pre-activity monitoring must be conducted for 30 minutes to ensure that the shutdown zone is clear of marine mammals, and pile driving may only commence when PSOs have declared the shutdown zone clear of marine mammals;(12) In the event of a delay or shutdown of activity resulting from marine mammals in the shutdown zone, animals must be allowed to remain in the shutdown zone (i.e., must leave of their own volition) and their behavior must be monitored and documented. If a marine mammal is observed within the shutdown zone, a soft start cannot proceed until the animal has left the zone or has not been observed for 15 minutes. Monitoring must occur throughout the time required to drive a pile;(13) If work ceases for more than 30 minutes, the pre-activity monitoring of the shutdown zones must commence. A determination that the shutdown zone is clear must be made during a period of good visibility;(14) If a marine mammal approaches or enters the shutdown zone, all pile driving activities at that location must be halted. If pile driving is halted or delayed due to the presence of a marine mammal, the activity may not commence or resume until either the animal has voluntarily left and been visually confirmed beyond the shutdown zone or 15 minutes have passed without re-detection of the animal;(15) Pile driving activity must be halted upon observation of a species entering or within the harassment zone for either a species for which incidental take is not authorized or a species for which incidental take has been authorized but the authorized number of takes has been met; and(16) Trained PSOs must be placed at the best vantage point(s) practicable to monitor for marine mammals and implement shutdown or delay procedures when applicable through communication with the equipment operator. 89 FR 5692 , 10/1/2024until 9/30/2029