MEMPHIS, Tenn. -- The fat pocketbook mussel or Potamilus capax is listed as a federally endangered species, with the largest population in the United States historically being found in the St. Francis River Basin within the Memphis District boundaries of the U.S. Army Corps of Engineers.
The Memphis-based dive team are highly trained and experienced biologists who have assisted other districts such as Pittsburgh, Little Rock, Rock Island and Mobile to be sure their Endangered Species Act responsibilities are met in regards to potential impacts on threatened or endangered mussels. However, the main focus of the team, a component of the Regional Planning and Environmental Division South, has been within the St. Francis River Basin.
“The Memphis District has been tasked with maintaining a vast flood control program within the basin that is responsible for protecting life and property and includes a system of channels, levees, pumping stations and other flood control structures extending from the hills of southeast Missouri to just north of Helena, Arkansas, and covers approximately 8,400 square miles,” said Mark Smith, Supervisory Biologist and leader of the dive team. “Populations of the endangered fat pocketbook mussel have been found throughout the basin, and efforts to protect the species while still maintaining the authorized flood control project have been the focus of the team’s efforts in the basin.”
Consultation efforts associated with the ESA, Section 7, and discussions between USACE and the U.S. Fish and Wildlife Service brought to light the need for a system-wide perspective of the fat pocketbook mussel population within the St. Francis River Basin.
Section 7 is a mandate directing all federal agencies to be sure that the actions they authorize, fund, or carry out do not put in jeopardy the continued existence of a species, or destroy or negatively modify critical habitats. Sampling conducted primarily by USACE, as well as the Arkansas Department of Transportation, Arkansas Game and Fish Commission, and other resource agencies, showed that the fat pocketbook mussel population in the basin appeared to be stable.
A recovery plan was developed by the USFWS listing the requirements to document the recovery of the mussel in order to remove a species from the federally protected threatened and endangered species under the Endangered Species Act.
Efforts first discussed during recovery team meetings led to the Conservation Plan for the fat pocketbook mussel in the St. Francis Basin of Arkansas. USACE coordinated with USFWS to ensure that actions were not harmful to the overall population of the species and also to develop data and document the overall population in the basin.
The conservation plan was signed on July 11, 2018, and the agreement between USACE and USFWS was formalized and the subsequent concurrence letter was then received from USFWS.
Two projects that the conservation plan has already positively impacted by saving time and money on were a proposed clean out of Ditch 10 located in Poinsett County in Arkansas and the Belle Fountain Ditch in southeastern Missouri.
Surveys were conducted at Ditch 10, where a 4-mile channel clean out was proposed using timed searches to collect, measure, and returning fat pocketbook mussels to their collection points. The project was cleared for construction after reporting the survey results to USFWS and concluding the Section 7 consultation on the project via email. Cost savings for the Ditch 10 project were estimated at approximately $60,000 in survey effort and at least two months’ time saved.
The Belle Fountain Ditch project involved replacing culverts, typically embedded structures that allow water to flow under roads or railroads or trails, and placing riprap, the rock or other material used to protect shoreline structures against erosion, around the new culverts.
The final action in the Section 7 process occurred when only one fat pocketbook mussel was found during this survey, and after USACE biologists consulted the USFWS Missouri staff over the phone while on site, the pocket mussel was relocated to a part of the stream that would not be impacted by the construction.
At this time a report and official correspondence with USFWS documented the final action. The entire survey, Section 7 consultation and relocation occurred on one day, saving a significant amount of time and funding.