UCI student team outlines multimodal options — pipeline, electric trucks, rail — for San Clemente sand replenishment

A team of UC Irvine Master of Engineering students presented the results of a city‑commissioned study on coastal sand replenishment to the San Clemente Coastal Advisory Committee on May 15, describing candidate inland sand sources and several transportation methods intended to reduce environmental and community impacts from repeat trucking.

The students said they began the project in January and evaluated receiver (discharge) beaches at North Beach, Pier area and South San Clemente; inland supply options including Prado Dam, San Juan Quarry, Santa Ana River and San Diego Creek; and transport methods ranging from conventional diesel trucking to electric trucks, slurry pipelines, conveyor belts and rail. The presentation aimed to identify “more sustainable and environmentally friendly” approaches than last year’s diesel‑trucked nourishment, the students said.

Why it matters: San Clemente’s beaches have required recurring nourishment; the city and regional partners repeatedly move sand to widen beaches that protect infrastructure, recreation and habitat. The students’ work mapped supply, cost and permitting trade‑offs and highlighted where the city might pursue pilots or multimodal approaches to reduce long‑term cost and emissions.

The team narrowed inland sources to Prado Dam and the San Juan Quarry as the most reliable in initial weightings, based on sediment availability, distance and logistics. For partnerships they identified Orange County, Corona and the Orange County Transportation Authority and Orange County Water District for Prado Dam; Irvine and Orange County entities for San Diego Creek; and an industry partnership (company name cited in the presentation) for San Juan Quarry.

On transportation, the students presented these technical and cost points: - Pipeline: a slurry pipeline concept the students described as using high‑density polyethylene in a protected alignment; they said the mix would be roughly three to four parts water to one part sand and that a changeable flow rate could meet an operational “5,000” target the presenters described (the unit was not specified in the slideshow). The group used a unit price they found of about $235 per linear foot for 12–14‑inch pipe to estimate a San Clemente coastal pipeline at roughly $4 million, with an additional $5 million if routed from Doheny to North Beach, while noting those figures excluded mobilization, pumping and permitting line items. - Conveyor belts: the students identified aggregate conveyors for short distances and estimated roughly $600 per linear foot using company pricing; applying that rate to different segments produced multi‑million‑dollar orders of magnitude (examples in the slides included totals the team presented as roughly $9–21 million for different reaches). They emphasized that those figures did not include infrastructure or site‑specific permitting costs. - Electric trucking and hybrid trucks: students said electric trucking scored highly on emissions and could be cheaper than diesel as EVs scale, but they cautioned that heavy‑duty electric semi availability and market readiness remain limited today; they pointed to the California Air Resources Board’s zero‑emission truck target as a long‑term driver of EV adoption. - Rail: discussions with OCTA staff materialized in the slides. Students reported an OCTA estimate implying more than 100 train trips and a delivery every 7–10 days for a large program; they flagged complexities including railcar availability, offloading equipment, coordination with passenger service and potential impacts to regional freight operations.

“Using electric trucking and conveyor belt would have the highest benefits overall,” the students told the committee, but they emphasized that the best transport depends on the chosen sand source, the scale of stockpiles and local geography. As a practical multimodal option the team proposed trucking to a local stockpile (they identified a vacant lot adjacent to the Beach Hut Deli as a candidate) followed by pipeline or belt delivery for the final leg, or rail to a nearby offload area with short‑haul conveyors to the beach.

Committee members pressed on partnerships and operability. Asked to expand on “partnerships,” a student named specific city and agency partners for each supply option and said the quarry relationship would likely be with industry operators; city staff and the university faculty present added that regulatory and right‑of‑way agreements would be required for any rail or pipeline path.

The students showed the North Beach nourishment from the prior year — a roughly 37,000‑cubic‑yard placement referenced in the slides — as the baseline and argued that upfront infrastructure investments (stockpiles, conveyors, pipeline) could reduce recurring costs across decades. They used a projected 50‑year comparison to show how an initial infrastructure cost could yield net savings versus repeated emergency trucking across multiple cycles.

Next steps and availability: the students said they are preparing a final report and posters to submit to the city before graduation in June. City staff and committee members asked for the full report and indicated the presentation would inform the city’s continuing sand‑sourcing and funding conversations.