Planning without the planners: South Carolina’s Section 319 local watershed planning process

•This research affirms the disconnect between land use planning and watershed-based planning in chosen pilot states.•The majority of surveyed South Carolina land use planners have not been involved in watershed-based planning as it is not an enumerated job duty.•Interview results show that planners’ participation impediments are primarily institutional.•They occur through institutional siloing and a lack of the Section 319 program’s awareness of land use and zoning to address water quality.•Planners are willing to assume roles in the watershed-based planning process through horizontal consistency with comprehensive plan updates