For the purpose of promoting the public safety, health, welfare, convenience, and enjoyment of public travel, to protect the public investment in public streets and highways, and to preserve and enhance the scenic beauty of lands bordering public streets and highways, it is declared to be in the public interest to regulate and restrict the establishment, operation and maintenance of junkyards in areas adjacent to the streets and highways within the city. The city council finds and declares that junkyards which do not conform to the requirements of this chapter are public nuisances.