Small Reservoir Distribution, Rate of Construction, and Uses in the Upper and Middle Chattahoochee Basins of the Georgia Piedmont, USA, 1950–2010

Abstract

Construction of small reservoirs affects ecosystem processes in numerous ways including fragmenting stream habitat, altering hydrology, and modifying water chemistry. While the upper and middle Chattahoochee River basins within the Southeastern United States Piedmont contain few natural lakes, they have a high density of small reservoirs (more than 7500 small reservoirs in the nearly 12,000 km 2 basin). Policymakers and water managers in the region have little information about small reservoir distribution, uses, or the cumulative inundation of land cover caused by small reservoir construction. Examination of aerial photography reveals the spatiotemporal patterns and extent of small reservoir construction from 1950 to 2010. Over that 60 year timeframe, the area inundated by water increased nearly six fold (from 19 reservoirs covering 0.16% of the study area in 1950 to 329 reservoirs covering 0.95% of the study area in 2010). While agricultural practices were associated with reservoir creation from 1950 to 1970, the highest rates of reservoir construction occurred during subsequent suburban development between 1980 and 1990. Land cover adjacent to individual reservoirs transitioned over time through agricultural abandonment, land reforestation, and conversion to development during suburban expansion. The prolific rate of ongoing small reservoir creation, particularly in newly urbanizing regions and developing counties, necessitates additional attention from watershed managers and continued scientific research into cumulative environmental impacts at the watershed scale.

Recent Changes in Stream Flashiness and Flooding, and Effects of Flood Management in North Carolina and Virginia

“…(), we assessed changes in flow‐regulating features of best management practices (e.g., wet and dry ponds, flood control dams, bioretention areas, stormwater wetlands, sand filters, and infiltration devices; henceforth BMPs) and artificial water bodies (e.g., farm ponds, golf course ponds, water supply reservoirs; henceforth AWBs) from 1991 to 2013 (see Supporting Information for shapefile). We included AWBs in our study because although AWBs are not designed to control floods, they store water during floods and are ubiquitous across the landscape (Smith et al ., ; Downing et al ., ; Ignatius and Jones, ). We compiled BMPs and AWBs data from multiple sources: the United States Army Corps of Engineers' National Inventory of Dams (National Inventory of Dams, accessed November 2012, http://geo.usace.army.mil/pgis/f?p=397:1:0), Global Reservoirs and Dams Database (Lehner et al ., ), National Anthropogenic Barrier Dataset (Ostroff et al ., ), Federal Emergency Management Agency's National Flood Hazard Layer (FEMA's Flood Map Service Center, accessed May 2013, http://www.msc.fema.gov/portal), National Hydrograph Database on Waterbodies (U.S. Geological Survey, accessed January 2013, http://nhd.usgs.gov/data.html), the North Carolina Department of Environment and Natural Resources' dam inventory (North Carolina Dam Inventory, accessed November 2012, http://portal.ncdenr.org/web/lr/dams), Virginia Database (personal communication, Mark Bradford, Virginia Department of Conservation and Recreation), and BMP databases maintained by individual counties.…”

“…Following methods of Mogoll on et al (2015), we assessed changes in flow-regulating features of best management practices (e.g., wet and dry ponds, flood control dams, bioretention areas, stormwater wetlands, sand filters, and infiltration devices; henceforth BMPs) and artificial water bodies (e.g., farm ponds, golf course ponds, water supply reservoirs; henceforth AWBs) from 1991 to 2013 (see Supporting Information for shapefile). We included AWBs in our study because although AWBs are not designed to control floods, they store water during floods and are ubiquitous across the landscape (Smith et al, 2002;Downing et al, 2006;Ignatius and Jones, 2014 , and BMP databases maintained by individual counties. We verified the existence of, mapped the surface area of, and dated BMPs and AWBs using Google Earth aerial imagery.…”

“…Increases in surface runoff due to expanding impervious surfaces from urban and suburban growth have been met with advances in stormwater management that reroute and retain surface runoff (Brown et al, 2005). The rate of reservoir construction was highest between 1980 and 1990, particularly in suburban areas, directly affecting streamflow and floods (Ignatius and Jones, 2014). Conversion from farmland to forest in the Piedmont region has also impacted streamflow (Brown et al, 2005;Kim et al, 2014).…”

Commonalities in stream connectivity restoration alternatives: an attempt to simplify barrier removal optimization

“…When conducting barrier removal assessments, there are generally several common limitations, and our study is no exception. First, most inventories of barriers within a given region are incomplete due to coarse mapping efforts that miss smaller impoundments (Ignatius and Jones 2010). While this is likely true for the RRB, the barrier assessment in WOC was extensive and included manually traversing the watershed to ensure a complete inventory (McManamay et al 2016).…”

An empirical assessment of which inland floods can be managed

“…We standardized BMP and AWB area across urban watersheds by calculating the cumulative percentage of BMP (% BMP) and AWB (% AWB) surface area by watershed area per year from 1991 to 2013. We weighted flowregulating capacity of AWBs and BMPs equally, because although AWBs are not constructed to control floods, they store water during floods, and are ubiquitous across the landscape (Smith et al, 2002b;Ignatius and Jones, 2014).…”