Carlsbad staff present 2026 Drainage Master Plan update; Coastal Commission review required before implementation

Planner Alex Patterson presented the 2026 Drainage Master Plan update to the Carlsbad Planning Commission on March 18, describing a city‑initiated Local Coastal Program (LCP) amendment and municipal-code adjustments that together identify 11 capital improvement program projects, including four projects not included in the 2008 plan. Patterson said the action before the commission was a high‑level program review and that project‑level design, cost refinement and project‑level environmental reviews would occur later.

Patterson told commissioners staff recommends adopting an EIR addendum and recommending LCP amendments to the city council, and he corrected the public‑notice window: the six‑week notice began March 18 and runs through April 29. "As part of the implementation of the 2026 drainage master plan, the applicant proposes to amend the local coastal program and Carlsbad municipal code," Patterson said. He emphasized the plan’s project list is expected to be funded through a proposed planned local drainage area (PLDA) fee and that separate project‑level reviews will follow.

Senior engineer David Edwards explained the plan’s engineering approach and fee calculation. The city divided Carlsbad into four watershed basins (A–D); each basin’s future developable area, projected impervious surface and growth share were used to allocate facility costs and derive a dollar‑per‑impervious‑acre fee. Edwards said the consultant analyzed flows for both 10‑year and 100‑year storms, noting the plan’s design goal is to contain a 10‑year storm in the storm drain and to keep 100‑year flows within the right of way. "For a 50‑year event, it's going to be somewhere in between," he said, adding the cost estimates are preliminary and will be refined at design and bid stages.

Staff reported a CEQA review found no new significant impacts requiring additional mitigation beyond the previously certified environmental documentation. Patterson and staff repeatedly noted that Coastal Commission review is required: "All aspects of the 2026 drainage master plan will not go into effect until after Coastal Commission approval," Patterson said.

Commissioners asked clarifying technical and fiscal questions—how the plan would perform under rare peak storms, how costs would be locked in and whether the fee methodology is adaptable. Edwards said cost figures are consultant estimates that become fixed only at the bid stage and that the hydrologic analysis covers 10‑ and 100‑year events. After brief discussion of the corrected noticing dates, the city attorney read an amended whereas clause for the draft ordinance; a motion to recommend the staff package was made, but the transcript of the provided segments does not record a final roll‑call vote on item 1.