Des Moines-based Confluence landscape architects and urban designers claims in a federal copyright lawsuit that a New York firm operating as Confluence by Cannon Design and Confluence by CannonDesign is causing confusion among customers. In a lawsuit filed Monday in U.S. District Court for the Southern District of Iowa in Des Moines, Confluence, the operating name for Brian Clark & Associates Inc., said both companies provide consulting services in landscape architecture and urban design. Confluence has used its name since at least July 7, 2008. The firm is asking for an order prohibiting CannonDesign from using the name "Confluence" as well as trebled damages.