Dam on Pearl River could affect coastal restoration, Louisiana agency says

Agency cites effect on wetlands efforts

Louisiana’s Coastal Protection and Restoration Authority has expressed concern that a proposed dam on the Pearl River in Mississippi could have negative environmental consequences for Louisiana and its efforts to rebuild eroding wetlands.

The authority sent a letter Thursday to the Rankin Hinds Pearl River Flood and Drainage Control District asking that its comments be addressed in an environmental impact statement being prepared for flood-control alternatives under consideration for the Jackson, Miss., metropolitan area.

One of the proposed initiatives — damming the Pearl River to create a 1,500-acre lake — is generating some controversy in Louisiana, particularly St. Tammany Parish.

The letter, signed by Executive Director Jerome Zeringue, follows one submitted last month by the Louisiana Department of Wildlife and Fisheries, which pointed to the large number of species in the lower Pearl River basin that it said need to be addressed in the environmental statement.

Wildlife and Fisheries questioned the project’s impact on oyster production, saying that changes in hydrology caused by the dam and lake could lead to a “drastic decline’’ in oyster production and render useless significant Louisiana investment in reef rehabilitation.

The Coastal Protection Authority conferred with Wildlife and Fisheries, Zeringue wrote, “and we reiterate the concerns and issues identified in their comment letter dated Nov. 27, 2013.’’

The new letter goes beyond the project’s possible effects on fish and wildlife, however. It also cites Louisiana’s comprehensive master plan for coastal restoration, which it says identifies projects in and around the Pearl River watershed.

“Those projects involve creating wetlands that would be sustained by freshwater from the Pearl River and building levees that would be buffered by those created and existing wetlands,’’ the letter says.

Any plans that would change the hydrology of the lower Pearl River could have an adverse impact on those coastal-restoration projects as well as on existing wetlands, the letter says, “undermining Louisiana’s ability to achieve a sustainable coast and protect our citizens from storm surges.’’

Despite those reservations, Zeringue’s letter acknowledges the flood district’s goal, saying that the coastal authority “keenly understands’’ the need to protect people and communities in the Jackson area from flooding and “supports the district in achieving this important goal in a manner that does not compromise our ability to do so in southeast Louisiana.’’

The letter calls for detailed ecological and storm-surge modeling to assess how the different alternatives would affect areas in and around the Lake Pontchartrain Basin.

The St. Tammany Parish Council passed a resolution in October opposing the dam because of fears it would reduce water levels downstream from the lake and hurt ecotourism.

Public comment on the proposed flood-control initiatives closed Nov. 29.

The flood district held two public meetings in Mississippi and a third in St. Tammany Parish last month to solicit public input. Louisiana residents who attended the meeting in St. Tammany stressed their fears that the project would mean a decrease in water flow in the lower Pearl River basin. They called for a full environmental impact study covering all the way to the mouth of the river.

Keith Turner, an attorney who represents the flood district, said all the comments received are being reviewed and will be made public, probably in early February. While more comments came from Mississippi, he said, the Louisiana response was “greater than a minor amount.’’

Comments from both Mississippi and Louisiana will be taken into consideration, he said. The agency plans to finish the environmental impact statement by the end of May.