101 Trunk Sewer and Batiquitos Gravity Sewer

As a result of recent master planning and dry-weather flow monitoring projects, the Leucadia Wastewater District identified a need to upsize approximately 2,000 linear feet of 10- to 12-inch diameter gravity sewer located along US-101 in the community of Leucadia, near the Carlsbad city line. The existing gravity sewer in this area is located beneath the sidewalk on the west side of the road, posing several challenges, cheif among them constructability of the replacement sewer, and access for future maintenance. The site is also environmentally sensitive because of its location between South Carlsbad State Beach immediately to the west and Batiquitos Lagoon to the east. 

IEC performed a detailed alternatives analysis, evaluating fasibility, cost, constructability, community and traffic impacts, and ease of permitting for several approaches, including replacement in place and replacement within parallel alignments(s). Based on this analysis, IEC's summary technical memorandum recommended replacement in a parallel alignment within the existing southbound lanes of US-101. Once the preferred approach was identified, the IEC team prepared and IS/MND for the project.

Key issues for CEQA analysis related to the proximity of beach and lagoon resources, and included aesthetic impacts; potential to disturb nesting special-status birds, including snowy plover, least tern, lightfooted clapper rail, and Belding's savannah sparrow; the need to remove native scrub plantings to accommodate piipeline installation; and a high likelihood of encountering buried cultural resources, which resulted in a decision to monitor all trench spoils during excavation.