The opinion of the court was delivered by: James Robertson United States District Judge
Pending before this court is a motion for preliminary injunction  to bar the United States Army Corps of Engineers from proceeding with a flood control project in the St. Johns Bayou Basin and New Madrid Floodway along the west bank of the Mississippi River in the southeast "boot heel" of Missouri. The Corps plans to begin construction on or around August 1, 2006, although it insists that the first phase of the project will involve nothing more than re-routing a drainage ditch and building a cofferdam with earthmoving equipment. For reasons set forth in this memorandum, I have concluded that plaintiffs have a substantial likelihood of success on the merits of one of their claims that this project cannot lawfully be completed. Because the outcome of the litigation remains uncertain, however; because the first phase of construction will inflict little injury and even less irreversible injury; and because the public interest favors moving this litigation along to an expeditious conclusion: I have decided to deny the motion for preliminary injunction upon condition that the Corps agree to demolish the cofferdam, straighten the drainage ditch, and restore the area as nearly as practicable to its present condition if judgment is ultimately entered against it.
The project in question resurrects, and combines, two flood control projects that were first envisioned in 1954 and in 1986, respectively. The first project, to close a quarter-mile gap in the Mississippi River levee that had been deliberately left open for the New Madrid Floodway, was approved by Congress in the Flood Control Act of 1954. 33 U.S.C. §701g. The levee closure was never implemented because it was opposed by landowners who were concerned that it would slow drainage from the Floodway. [58-1] at 6. The second project, a pumping station in the St. Johns Bayou Basin, was authorized in the 1986 Water Resources Development Act (WRDA), Pub. L. 99-662, but local project sponsors were unable to meet statutory cost-sharing requirements [61-1] at 5. Serious flooding in the mid-1990s attracted renewed Congressional attention, and the combination project finally gained traction in 1996, when President Clinton designated the town of East Prairie (which lies in the St. Johns Basin flood plain) an enterprise community, and Congress authorized East Prairie to use enterprise grants to fund the St. Johns component of the project. 1996 WRDA, Pub. L. No. 104-303.
The New Madrid Floodway portion of the project is immediately adjacent to the Mississippi River. Most of the targeted project area is located behind a riverside levee called the "mainline" or "frontline" levee. The New Madrid Floodway is separated from the St. Johns Basin by a second levee, the "backline" levee. Large areas within the Floodway and the Basin are subject to periodic flooding at unpredictable intervals, resulting in damage to public utilities, disruptions in access to towns, farms, and other facilities, and, in high-water years, steep drops in agricultural production and with commensurate loss of local farm revenues, the main source of income for the area.
 at 4. The Floodway side of the project area tends to flood from below (from downriver, to the south), while the lower area of land otherwise protected by the St. Johns levee system floods from above. The Corps project is designed to provide flood protection and reduce flood damage in both the St. Johns Bayou Basin and New Madrid Floodway.
A. The New Madrid Floodway Project
The Mississippi River floods into the New Madrid Floodway during winter and spring on essentially an annual basis. The Floodway was designed in 1933 to carry excess river water in a bed parallel to the Mississippi, from approximately the confluence of the Mississippi and Ohio Rivers to the current disputed project area -- a 1500-foot gap between the frontline and backline levees designed to allow water to exit the riverside Floodway and re-enter the main channel. Even if water is not draining down from further up the Floodway, high water sometimes enters this lower end opening, causing interior flooding as the river rises. [61-1] at 3. When that occurs, the levee gap allows overflow flooding onto to tens of thousands of acres in the flood plain.
The New Madrid Floodway project would close the 1500 foot gap in the levee, leaving four 10-foot-diameter pipes that can be opened and closed to control water flow. [61-1] at 4.
The St. Johns portion of the project would install two massive pumps to further drain the Floodway and the adjacent St. John's Basin. The St. Johns Basin is located further west, adjacent to the Floodway, and abuts the river channel only along its northeast face and at the extreme southern (bottom) end of the levee. Because the southern end of the Basin is already protected by a levee with a set of control gates, the flood plain within the St. Johns structure does not experience "backwater" flooding like that occurring in the Floodway. The St. Johns side of the project, however, drains an area significantly greater than the Floodway, so that rains that occur over the Basin when there is high water in the Mississippi River also tend to produce significant flooding at the southern end of the Basin, inside the levee.  at 3-4. The planned pump system would help alleviate and control flooding in the Basin.
C. The Environmental Aspects of the Project
The core complaint of these plaintiffs is that the New Madrid Floodway/St. Johns Basin project would wall-off and drain the last significant piece of flood plain that still remains connected to the Mississippi River. [58-1] at 1. The 1500-foot levee gap that would be closed by the project allows the waters of the Mississippi River -- and fish -- to enter the Floodway basin. According to United States Fish and Wildlife Service, the New Madrid Floodway is "unique in Missouri because it is the only significant portion of the historic Mississippi River flood plain still largely connected to the river." [58-1] at 6. There is no dispute that late winter and early spring flooding on forest and cropland in the project area provides valuable wildlife habitat. Half of all the fish that use the Mississippi River rely on the New Madrid flood plain to reproduce. The Corps' Environmental Impact Statement (EIS), required for any federal construction project by The National Environmental Policy Act of 1969, 42 U.S.C. §§ 4321-4347, praises the "diversity and abundance" of fish in the project area. The area also provides habitat for hundreds of species of water-dependent birds, hundreds of thousands of waterfowl, and "unmatched habitat for amphibians and reptiles." [58-1] at 10. Many of the fish do not live in the affected area, but instead migrate into the flood plains to mate before returning to the main river. The mating season for fish is the high water season on the Mississippi.
The Corps plan would affect somewhere between 18,000 and 36,000 acres of wetland, [58-1] at 9-10, and the animals living therein. It would also close off the 1500-foot opening that the fish now use for access to the Floodway, leaving the fish to navigate four ten-foot wide gates as best they can in order to gain access to whatever wetlands, or mitigation sites, remain. [58-1] at 14-15. The Corps generally plans to keep the levee gates closed when the sump area would be flooded, blocking access precisely when habitat could theoretically be available. In years with the most flooding, the gates would be closed during the entire or nearly the entire fish spawning season. The Corps' second Environmental Impact Statement asserts that the gates will be open much of the time, but that claim, according to the plaintiffs, is based on the Corps' old plan. "Under the new plan ... the gates would mostly be open only in years when the sump area is not flooded, so there would be no fish habitat available even if the fish moved through the gates." [58-1] at 15.
The Corps issued a Record of Decision (ROD), representing the agency's decision to move forward with the project, in August 2003. Plaintiffs filed this action, challenging the ROD and the underlying 2002 Environmental Impact Statement, on September 9, 2004. In 2005, during the course of summary judgment briefing, the Corps withdrew the ROD, [61-1] at 6-7, because it contained a significant math error affecting the number of acres of land the Corps would need to procure in order to mitigate the project's impact. [58-1] at 8. In November 2005, the Corps issued a draft of the second Environmental Impact Statement and received public comments, including comments from these plaintiffs. On May 23, 2006, the Corps issued a new ROD, approving the recommended plan for construction. The Corps has stated that it will not issue a Notice to Proceed with construction until at least August 1, 2006, at the earliest, and that no work will be done onsite until that notice is issued. [61-1] at 7.
E. The First Phase Work that will be Done Beginning on August 1, 2006
Completion of the entire project would take many years. In the current season, in the period after August 1, 2006, the Corps would be able to complete only the first phase of the project. This would involve the early stages of construction of the planned New Madrid pumping station -- essentially the construction of an earthen cofferdam and sections of the final levee structure, allowing flood water and riverine fish species continued access to the flood plain across a 450-foot gap. [61-1] at 11. The Corps will also reroute a portion of Mud Ditch, which conveys water from the area to the Mississippi River. [61-1] at 12. Any further work would wait until well into 2007.
A four-part test governs any request for the extraordinary relief of preliminary injunction. This test considers: (1) the plaintiff's likelihood of success on the merits; (2) the irreparable injury if an injunction is not granted; (3) potential injury to the other party; and (4) the public interest. City Fed Fin. Corp. v. Office of Thrift Supervision, 58 F.3d 738, 746 (D.C. Cir. 1995). The D.C. Circuit's test is a flexible one. "If the arguments for one factor are particularly strong, an injunction may issue even if the arguments in other areas are rather weak." Id. at 747. Even under the sliding scale, the burden remains on the plaintiff to demonstrate that all four factors are met. Mova Pharm. v. Shalala, 140 F.3d 1060, 1066 (D.C. Cir. 1998). The Court of Appeals has also ...