Freshwater mussel, aquatic plants, and sediment characteristics associated with a habitat rehabilitation and enhancement project in Navigation Pool 13 of the upper Mississippi River

To establish benthic conditions before construction of an Upper Mississippi River Restoration Program habitat restoration and enhancement project (HREP) in Navigation Pool 13, we sampled native freshwater mussels, tubers from watercelery (Vallisneria americana) plants, and surficial sediment with a stratified systematic survey design from 9/24/2024 to 10/4/2024. About 300 sites were sampled across three strata based on post-project predictions: 1) areas with increased velocity, 2) areas with reduced velocity, and 3) control (no net change in velocity). At each site, divers obtained estimates of unconfined sediment compressive strength (via a penetrometer) and particle size via visual or tactile assessment of surficial substrate. Next, divers excavated the top 15 cm of river sediment to 1) characterize the native freshwater mussel assemblage, 2) quantify the number of watercelery tubers and 3) obtain sediment samples for particle size distribution in the laboratory. The resultant data describe sediment characteristics related to substrate stability (particle size and compressive strength) and iconic members of the benthic community (native freshwater mussels and watercelery) in Pool 13 of the upper Mississippi River.