The city’s Finance Committee has approved a contract to extend the riverwalk from Jackson Falls Condominiums to Margarita’s  restaurant. The $47,700 contract was awarded to Saint’s Landscaping, the lowest of eight bidders for the project. In addition to extending the 8-foot-wide concrete-and-brick walkway by 240 feet, the work will add benches, three solar-powered street lamps, and a rain garden to the promenade along the Nashua River. The work is expected to be completed by June 1.