DOE OSTI2019
One of the primary threats to Mexican Spotted Owls at the Los Alamos National Laboratory (LANL) is noise disturbance during the nesting season from vehicular traffic, construction activities, and explosives testing. The other primary threat is from habitat loss or alteration. Sigma Mesa is located between Sandia Canyon to the north and Mortandad Canyon to the south, and is within Technical Area 60. Since Sigma Mesa is within an Area of Environmental Interest (AEI) for the Mexican Spotted Owl, any increase in operational activities requires evaluation under the LANL Habitat Management Plan. This study was completed to support a biological assessment to analyze the effects of the installation of a new asphalt batch plant and additional vehicular traffic on Sigma Mesa. We conducted noise monitoring using calibrated noise level meters at various locations around the project site. This included daytime, nighttime, and weekend measurements. The noise cycle levels around Sigma Mesa vary throughout the week and by measurement location. In developed areas, current noise levels were significantly higher during the day due to daytime operations. In undeveloped areas, noise levels were significantly higher at night due to natural noise primarily from insects. Weekend noise was significantly lower in developed areas and was not significantly different in undeveloped areas. Weekday operations are reduced during the weekend resulting in less noise. Since most of the operational noise is attenuated during the week, noise levels in undeveloped areas are not significantly different during the weekend. In comparison to a noise study performed in 2005 in the same general area, current noise levels have increased in developed areas around Sigma Mesa, but have not increased in undeveloped areas that are lower in elevation. This is due to natural noise attenuation over distance and elevation gradients.
54 ENVIRONMENTAL SCIENCES↗