Anthropogenic landforms and sediments from dredging and disposing sand along the Apalachicola River and its floodplain

Abstract

2017-08-25T16:28:03

Mapping and Modeling the Distribution, Abundance, and Habitat Associations of the Endangered Fat Threeridge in the Apalachicola River System

“…We suspect these attributes, if also shared by A. neislerii, may help explain the pattern of distribution and dominance of the species in mesohabitats of the Apalachicola system characterized by stable, fine sediments. Furthermore, it stands to reason that the cessation of dredging, dredge spoil disposal, and snag removal activities in the Apalachicola system nearly 20 y ago (Mossa et al 2017) and the management of minimum discharge levels and river drawdown rates (USACE 2012;USFWS 2012) have also served to restore a degree of habitat stability and equilibrium to the system with expected benefits to freshwater mussels that not only depend on, but also thrive under such conditions.…”

“…This culturally important waterway played a vital role in the history of the region as a transportation and commercial trading route during pre-and post-Civil War periods (Mueller 1990). To provide these and related services, the river was subject to substantial modification in the form of channel straightening, snag removal, groin construction, impoundment and flow regulation, and channel dredging during the late 19th and 20th centuries Brim Box and Williams 2000;Mossa et al 2017). Anthropogenic modification of physical habitat and flow regimes are frequently cited causes of freshwater mussel decline and imperilment in large river systems (Neves et al 1997;Watters 2000), and these alterations probably impacted the mussel fauna of the Apalachicola to some degree (USFWS 2003).…”

Geoarchaeological investigations at the Ryan‐Harley Paleoindian site, Florida (8JE1004): Implications for human settlement of the Wacissa River Basin during the Younger Dryas

“…A digital elevation model (DEM) was created to visualize the surface of Unit 3 at the time of occupation (Figure 8). This model reveals that the overall terrain is dissimilar to that of typical karstic floodplains or river banks in the region (Mossa, Chen, Walls, Kondolf, & Wu, 2017; Randall, 2014) and has no obvious fluvially derived features. Instead, the landscape bears hummocky microtopography and compares favorably with eolian landscapes (Baas & Nield, 2007; Rango et al, 2000; Tripaldi, Mehl, & Zárate, 2018; Woolard & Colby, 2002).…”

Channel and vegetation recovery from dredging of a large river in the Gulf coastal plain, USA

“…These water issues are the reason for a series of lawsuits between various cities, states, and government agencies in the basin over several decades (Rugel et al ., 2012; Hamann, 2013; Mitra et al ., 2016; Klein and Sandfort, 2019). Stage levels in the 170 km‐long (106 mile) river have declined due to both reduced flow inputs from upstream and channel changes associated with the dams and channel modifications for the failed navigation projects, including dredging, artificial cutoffs, and snag removal (Light et al ., 1998, 2006; Mossa et al ., 2017). Water‐level declines from 1954 to 2004 were greatest (~1.43 m) in the reach directly downstream of Jim Woodruff Dam at river mile (RM) 106, reflecting a combination of widening and incision.…”

“…Thus, our case study aimed to assess the passive recovery in the mid‐Apalachicola River in Florida, USA from the effects of dredging, disposal, and de‐snagging for a navigation project by the U.S. Army Corps of Engineers. Some documented impacts include channel widening (Price et al ., 2006; Darst and Light, 2008) and larger sand bars due to direct disposal of sediment and lower water levels exposing more of the bed (Mossa et al ., 2017). We examine the overall trends and spatial variations of river recovery as measured by sand bar size and net changes in land cover at comparable discharges to assess passive recovery of the system from dredging and related impacts.…”