5 Mitigation Northwest Training and Testing Draft Supplemental EIS/OEIS March 2019 Supplemental Environmental Impact Statement/ Overseas Environmental Impact Statement Northwest Training and Testing TABLE OF CONTENTS 5 MITIGATION ..............................................................................................................5-1 5.1 Introduction ........................................................................................................................ 5-1 5.1.1 Benefits of Mitigation .............................................................................................. 5-2 5.1.2 Compliance Initiatives.............................................................................................. 5-2 5.1.2.1 Protective Measures Assessment Protocol .............................................. 5-3 5.1.2.2 Monitoring, Research, and Reporting Initiatives ...................................... 5-3 5.2 Mitigation Development Process ........................................................................................ 5-8 5.2.1 Procedural Mitigation Development ....................................................................... 5-8 5.2.1.1 Lookouts ................................................................................................... 5-9 5.2.1.2 Mitigation Zones ..................................................................................... 5-10 5.2.1.3 Procedural Mitigation Implementation .................................................. 5-11 5.2.2 Mitigation Area Development ............................................................................... 5-12 5.2.3 Practicality of Implementation .............................................................................. 5-13 5.2.3.1 Assessment Criteria ................................................................................ 5-13 5.2.3.2 Factors Affecting Practicality .................................................................. 5-16 5.3 Procedural Mitigation to be Implemented ....................................................................... 5-18 5.3.1 Environmental Awareness and Education ............................................................. 5-18 5.3.2 Acoustic Stressors .................................................................................................. 5-19 5.3.2.1 Active Sonar ............................................................................................ 5-19 5.3.2.2 Weapons Firing Noise ............................................................................. 5-24 5.3.3 Explosive Stressors................................................................................................. 5-26 5.3.3.1 Explosive Sonobuoys .............................................................................. 5-26 5.3.3.2 Explosive Torpedoes ............................................................................... 5-29 5.3.3.3 Explosive Medium-Caliber and Large-Caliber Projectiles ....................... 5-31 5.3.3.4 Explosive Missiles ................................................................................... 5-35 5.3.3.5 Explosive Bombs ..................................................................................... 5-38 5.3.3.6 Explosive Mine Countermeasure and Neutralization Activities ............. 5-41 5.3.3.7 Explosive Mine Neutralization Activities Involving Navy Divers ............. 5-44 i Table of Contents Northwest Training and Testing Draft Supplemental EIS/OEIS March 2019 5.3.4 Physical Disturbance and Strike Stressors ............................................................. 5-48 5.3.4.1 Vessel Movement ................................................................................... 5-48 5.3.4.2 Towed In-Water Devices......................................................................... 5-51 5.3.4.3 Small-, Medium-, and Large-Caliber Non-Explosive Practice Munitions 5-52 5.3.4.4 Non-Explosive Missiles ........................................................................... 5-53 5.3.4.5 Non-Explosive Bombs and Mine Shapes ................................................ 5-55 5.4 Mitigation Areas to be Implemented ................................................................................ 5-56 5.5 Measures Considered but Eliminated ............................................................................... 5-56 5.5.1 Active Sonar ........................................................................................................... 5-57 5.5.2 Explosives ............................................................................................................... 5-59 5.5.3 Active and Passive Acoustic Monitoring Devices .................................................. 5-60 5.5.4 Thermal Detection Systems and Unmanned Aerial Vehicles ................................ 5-61 5.5.5 Third-Party Observers ............................................................................................ 5-63 5.5.6 Foreign Navy Mitigation ........................................................................................ 5-64 5.5.7 Reporting Requirements........................................................................................ 5-65 5.6 Mitigation Summary ......................................................................................................... 5-65 List of Figures There are no figures in this chapter. List of Tables Table 5.3-1: Environmental Awareness and Education ........................................................................... 5-18 Table 5.3-2: Procedural Mitigation for Active Sonar ............................................................................... 5-20 Table 5.3-3: Procedural Mitigation for Weapons Firing Noise ................................................................ 5-24 Table 5.3-4: Procedural Mitigation for Explosive Sonobuoys .................................................................. 5-26 Table 5.3-5: Procedural Mitigation for Explosive Torpedoes .................................................................. 5-29 Table 5.3-6: Procedural Mitigation for Explosive Medium-Caliber and Large-Caliber Projectiles ........................................................................................................................... 5-32 Table 5.3-7: Procedural Mitigation for Explosive Missiles ....................................................................... 5-35 Table 5.3-8: Procedural Mitigation for Explosive Bombs ......................................................................... 5-39 Table 5.3-9: Procedural Mitigation for Explosive Mine Countermeasure and Neutralization Activities .............................................................................................................................. 5-42 Table 5.3-10: Procedural Mitigation for Explosive Mine Neutralization Activities Involving Navy Divers ......................................................................................................................... 5-44 Table 5.3-11: Procedural Mitigation for Vessel Movement..................................................................... 5-49 Table 5.3-12: Procedural Mitigation for Towed In-Water Devices .......................................................... 5-51 ii Table of Contents Northwest Training and Testing Draft Supplemental EIS/OEIS March 2019 Table 5.3-13: Procedural Mitigation for Small-, Medium-, and Large-Caliber Non-Explosive Practice Munitions .............................................................................................................. 5-53 Table 5.3-14: Procedural Mitigation for Non-Explosive Missiles ............................................................. 5-54 Table 5.3-15: Procedural Mitigation for Non-Explosive Bombs and Mine Shapes .................................. 5-55 iii Table of Contents Northwest Training and Testing Draft Supplemental EIS/OEIS March 2019 This page intentionally left blank. iv Table of Contents Northwest Training and Testing Draft Supplemental EIS/OEIS March 2019 5 Mitigation 5.1 Introduction This chapter describes the mitigation measures that the United States (U.S.) Department of the Navy (Navy) will implement to avoid or reduce potential impacts from the Northwest Training and Testing (NWTT) Supplemental Environmental Impact Statement (EIS)/Overseas Environmental Impact Statement (OEIS) Proposed Action. This chapter has been updated in its entirety since Chapter 5 (Standard Operating Procedures, Mitigation, and Monitoring) of the 2015 NWTT EIS/OEIS (U.S. Department of the Navy, 2015). As a cooperating agency for the Proposed Action, the U.S. Coast Guard will implement applicable mitigation measures developed by the Navy for the Proposed Action. The Navy will also implement standard operating procedures specific to training and testing activities conducted under the Proposed Action. In many cases, standard operating procedures provide a benefit to environmental and cultural resources, some of which have high socioeconomic value in the Study Area. Standard operating procedures differ from mitigation measures because standard operating procedures are designed to provide for safety and mission success, whereas mitigation measures are designed specifically to avoid or reduce potential environmental impacts. An example of a standard operating procedure is that ships operated by or for the Navy have personnel assigned to stand watch at all times when underway. Watch personnel monitor their assigned sectors for any indication of danger to the