Historic mill ponds and piedmont stream water quality: Making the connection near Raleigh, North Carolina

Freeze–thaw processes and intense rainfall: the one-two punch for high sediment and nutrient loads from mid-Atlantic watersheds

“…The influence of freeze-thaw cycles and intense winter rain events on sediment and particulate nutrient exports is especially of concern considering the large reservoir of valley-bottom legacy sediments in eastern US Piedmont watersheds (Merritts et al 2011;Walter and Merritts 2008;Wegmann et al 2012). Streambank legacy sediments represent a large potential supply of near-stream sediments and freeze-thaw activity represents a key destabilizing mechanism that can increase the ''availability'' of this large sediment reservoir (Couper 2003;Lawler 1993a).…”

“…Excess sediment can decrease water clarity and light penetration and bury valuable spawning beds, while nutrients transported with sediments can contribute to eutrophication of aquatic ecosystems (Henley et al 2000;Waters 1995). Sediment input to streams and aquatic ecosystems can originate from upland sources such as erosion of cropland, urban construction sites, and unpaved road surfaces, and/or from near-stream sources such as streambank and bed erosion (USEPA 2016b;Walling 2005).…”

“…Low head milldams (typically 1-3 m) raised base level, reduced flow velocities, and resulted in substantial sediment accumulation behind the dams (Walter and Merritts 2008). Many of the dams have now breached and their upstream reservoirs eroded, resulting in highly incised contemporary streams with exposed vertical streambanks that are vulnerable to erosion (Merritts et al 2011(Merritts et al , 2013Pizzuto and O'Neal 2009;Wegmann et al 2012). Not surprisingly, studies have reported anomalously elevated rates of bank erosion and sediment exports from watersheds in the Piedmont region of the eastern US (Merritts et al 2011;Donovan et al 2015;Gellis et al 2009;Mukundan et al 2010;Stewart et al 2015;Voli et al 2013).…”

Sediment contributions from floodplains and legacy sediments to Piedmont streams of Baltimore County, Maryland

“…Researchers have long observed the process of laterally migrating lowland channels eroding through historical valley-spanning deposits that resulted from upland land use activities following European settlement (Happ et al, 1940;Costa, 1975;Jacobson and Coleman, 1986;Phillips, 1991;Jackson et al, 2005;Wegmann et al, 2012). Such historical deposits, collectively referred to as legacy sediments (Fig.…”

Riparian and valley-margin hardwood species of pre-colonial Piedmont forests: A preliminary study of subfossil leaves from White Clay Creek, southeastern Pennsylvania, USA

“…European settlement significantly affected the hydrogeomorphology and associated wetland and riparian flora throughout the Piedmont region due, in large part, to the mills, forges, furnaces, and mining operations settlers built to support their communities (Walter and Merritts, 2008;Voli et al, 2009;Wegmann et al, 2012). These structures were dependent on hydropower provided by tens of thousands of dams erected on streams throughout the region (Walter and Merritts, 2008;Merritts et al, 2013).…”