Why are the RTRP transmission lines underground in Jurupa Valley but above-ground in Norco?

In March 2020, the California Public Utilities Commission (CPUC) granted Southern California Edison (SCE) a certificate of public convenience and necessity for the Riverside Transmission Reliability Project. The decision explains that, before and after Riverside certified the EIR, the City of Jurupa Valley approved residential and commercial developments within the proposed alignment for SCE’s portion of RTRP. As a result, in September 2016, SCE revised its proposed transmission line route to avoid these projects. These revisions posed potentially new or increased impacts that were not addressed in the 2013 EIR. Accordingly, the Commission’s Energy Division issued a subsequent environmental impact report (SEIR) on October 2, 2018, to address the impacts of the revised portion of the project.The revised project would underground approximately 2 miles of the transmission line within the City of Jurupa Valley.