Proposed Drainage improvements and Restoration Activities at the Rancho Mission Viejo Riding Park

Full Title: 2026 East End Horse Stable Project, Addendum to the Previously Adopted Final Initial Study (IS) and Mitigated Negative Declaration (MND) for the Proposed Drainage Improvements and Restoration Activities at the Rancho Mission Viejo Riding Park at San Juan Capistrano Premier Equisport Events, LLC (Premier) operates the City-owned Riding Park property at the Rancho Mission Viejo Riding Park, San Juan Capistrano, pursuant to a Ground Lease approved by the City Council in July 2025. Premier is responsible for operating and maintaining the property's existing water quality infrastructure, known as the Concentrated Animal Feeding Operation (CAFO) Water Quality Improvements. Premier proposes the 2026 East End Horse Stable Project, which includes: (1) eight standard-size row-stall horse barns similar to, or the same as, the existing horse barns on-site, which would be approximately 9 feet in height and would include 10-foot by 12-foot stalls arranged side-by-side in two rows, accommodating up to approximately 315 stalls total; and (2) berms and a dedicated stormwater capture and infiltration basin intended to isolate and manage stormwater generated by the new horse stables. The proposed system would operate independently from the existing CAFO water quality infrastructure. The proposed project was evaluated under CEQA through an Addendum to the previously adopted 2020 Mitigated Negative Declaration. The Addendum concludes that the project would not result in new significant environmental impacts or substantially increase the severity of impacts previously identified. The existing Mitigation Monitoring and Reporting Program remains applicable, and no additional mitigation measures are required. Premier has also received the necessary authorization from the San Diego Regional Water Quality Control Board under the applicable Industrial General Permit framework. On August 18, 2026 the City Council of the City of San Juan Capistrano, after considering the Addendum and the IS/MND, adopted the Addendum, found the 2026 East End Horse Stable Project “functionally equivalent” to the previous Drainage Improvements and Restoration Activities, and approved the Revised Project.