National Harbor -- an entertainment complex proposed for Smoot Cove in Prince George's County -- will cause a dramatic increase in traffic in the area. It will affect a National Heritage river -- the Potomac -- and intrude upon residential communities with the intensive development of 292 acres of land, a 24-hour lighting system and an estimated 12 million visitors per year.

Notwithstanding these significant effects, The Post [editorial, June 11] cautioned against regulations being "idly invoked" to delay this project. The editorial, however, ignored the purposes of the environmental review process.

The National Capital Planning Commission, which is the central planning agency for this region, has an obligation under federal law to review the National Harbor proposal and alternatives to the project and issue an environmental impact statement. This process is supposed to ensure informed decision-making and to provide information to the public.

For a large, controversial project such as National Harbor, it is important to have a clear understanding of its positive and negative impacts before committing valuable, natural resources to development. The Post's editorial said that parkland along the Potomac is "plentiful," but it didn't note that access to the shoreline can be whittled away by individual development projects.

When federal parkland at Smoot Cove was transferred to Prince George's County, public access to the shoreline was contemplated; however, National Harbor dramatically reduces such access. The impact statement needs to take this cost into consideration and to document the purported benefits of the project.

In a May letter to the commission, the Environmental Protection Agency also noted another shortcoming of the impact statment -- it provided no support for the assertion that low-income and minority residents would benefit from training, job search and development activities related to National Harbor.

In addition to identifying National Harbor's possible effects, an impact statement also should review project alternatives. Opponents of National Harbor have argued for a smaller project, a park, no project or rejuvenation of existing retail and commercial areas. Each of these alternatives should be scrutinized in the review process to enable the commission, government agencies and the public to better weigh the balance between economic benefits and natural resources.

National Harbor is not simply a debate about development vs. environmental protection. It is a debate about what kind of development would most benefit the county. Chapman's Forest and PortAmerica showed that not all development proposals are good. County residents need commercial and retail establishments, but they also need natural amenities. The impact statement provides a vehicle for evaluating that trade-off.

In order for the review process to work, however, the commission needs to provide complete information about the project's effects, and it needs to be responsive to concerns raised by other agencies and by the public. Unfortunately, the commission has not yet met either of these responsibilities.

-- Caroline S. Park

of the Institute for Public Representation at Georgetown University Law Center, represents six environmental groups including the Sierra Club and the Maryland Bass Federation.