Noise assessment guidance for Biological Assessments

Use the information below, in addition to Chapter 7: Construction Noise Impact Assessment of the Biological Assessment (BA) preparation manual, when assessing noise impacts to marine mammals, marbled murrelets, and fish for National Marine Fisheries Service (NMFS) and U.S. Fish and Wildlife Service (USFWS) consultations. If underwater noise monitoring is required, use the underwater noise monitoring plan template.

For terrestrial noise assessments, use the information in Chapter 7 of the BA preparation manual to help determine the appropriate decibel levels for background sound, traffic noise, and construction noise. 

Threshold tables and guidance

The links below provide information on marine mammal, fish, and marbled murrelet injury and disturbance thresholds for impulsive and continuous underwater sound, and estimated auditory bandwidths (estimated hearing frequency ranges) for marine mammals and fish.

The USFWS presentation below introduced marbled murrelet in-air noise masking guidance for marine water pile driving projects. USFWS is using this guidance in marine pile driving consultations.

Noise analysis spreadsheets

Use these NMFS spreadsheets for noise assessments of underwater pile driving.

Use this USFWS spreadsheet for noise assessments of impact pile driving on marbled murrelets and/or bull trout or when calculating the distance to various thresholds.

Pile driving information

Use the data in Chapter 7 (pdf 1.9 mb) of the BA Manual to estimate sound pressure and cumulative sound exposure levels for various pile diameters and types. WSDOT pile driving monitoring reports can help with site-specific information for projects in the same or similar areas. Use the link to the CalTrans pile driving compendium (pdf) for additional information.

Underwater noise monitoring plan template

If a project involves impact pile driving where sound pressures generated may be above the disturbance thresholds for aquatic listed species (through in-water transmission), noise monitoring may be required.

To standardize the collection and reporting of underwater noise monitoring data, use the required Underwater Noise Monitoring Plan template (doc 319 kb).

Use this template to create a monitoring protocol for the project and then include it in the BA as an appendix. Check this webpage for the most current version of the template prior to use.

Additional acoustical references

Use these additional links for more information.