LYNN – Lynn Water and Sewer Commission (LWSC) officials say plans to expand the Walmart store and build a Lowe’s Home Improvement Center on Highland Avenue in Salem will impact the agency’s drainage system.The concerns were first raised in a March 31 letter from LWSC Executive Director Daniel O’Neill to Joseph Correnti, the Salem attorney representing the Kennedy Development Group.”Please be advised that any infrastructure connections, including water, sewerage and storm water from this development to Lynn’s system will require the permission of the Lynn Water and Sewer Commission,” O’Neill wrote.O’Neill said any approval from the agency must be preceded by a review of the development plans, specifically as they relate to calculations of drainage and sanitary sewer flow.According to O’Neill, “These reports will be required to assure the commission and its abutting ratepayers that this development will not impact the capacity of the existing utilities in Lynn.”Austin F. Turner, senior engineer at Framingham-based Tetra Tech Rizzo and hired by the development team, forwarded a copy of the plans to O’Neill in April, noting, “The project does not propose any infrastructure connections to the city of Lynn’s system.”In addition to increasing the size of the Walmart by half and building the Lowe’s Home Improvement Center, the project includes doubling the size of the Meineke auto service business on the property, purchasing a tract of land from the abutting Camp Lions to increase the square footage of the development site and erecting a municipal water storage tower for the city of Salem.Andrew Hall, an engineer and project manager at the LWSC, disagreed with Turner’s assessment. In his May 17 response letter to Tetra Tech Rizzo and Bohler Engineering, he cited the direct connection of four catch basins in the relocated Camp Lions access drive to a MassHighway-owned drain in Western Avenue.That drain ties into a 24-inch diameter drainage system on Coolidge Road, owned and maintained by the LWSC, Hall wrote.”The Lowe’s extended dry retention basin and the future Camp Lions extended dry retention basin are also tributary to the 24-inch drainage system on Coolidge Road,” Hall said.Hall has requested a copy of the developer’s drainage design calculations “to see that downstream Lynn residents are not adversely affected.”Drainage has been an issue because the big-box stores cover thousands of square feet of land, as do their parking lots and the access roads. Area residents fear flooding during rainstorms or spring runoff.The Salem Planning Board has been holding well-attended hearings on the project because the developers need a special permit in order to proceed. The hearings have focused on vehicular traffic, environmental impact, congestion and other issues. Most of the opposition has come from Lynn residents, many of whom will look up at the Lowe’s store because plans call for its construction on elevated ground. However, many Salem residents have complained as well.If the development goes forward, Camp Lions will receive proceeds from the sale of its acreage and see its buildings and facility improved as part of the deal. Salem will get a new water tower and, as Salem Mayor Kimberley Driscoll repeatedly has explained, the project will create jobs and bring in much-needed tax revenue.The next hearing before the Salem Planning Board is June 3 at 7 p.m. at 120 Washington St. The board does not meet in August.