US Representative Niki Tsongas recently joined Mayor James J. Fiorentini, Democratic state Representative Brian Dempsey of Haverhill, and other local officials to discuss and tour the downtown floodwall, which has been flagged by the Army Corps of Engineers for noncompliance after failing several inspections. The wall borders the city’s central business district. Under federal law, communities must certify floodwalls and flood-control systems to be eligible for federal aid in the event of a major flood. The certification also affects businesses and homes; noncompliance subjects them to significantly higher insurance premiums. The city, with Tsongas’s support, last year developed a plan to repair the floodwall and applied for a federal grant to complete the work. That application is now being reviewed.