Infrared satellite image of the intense rainfall being funneled into South Carolina during the morning of October 3, 2015. Note the location of Hurricane Joaquin. (http://www.weather.com/news/news/stunning- meteorological-images-october-2015-flooding, NASA).  

... 3-dimensional view of the Old Mill Pond Dam breach based on SfM- reconstruction from the Octo-Copter Drone Survey (N 33.97683°, W 81.22961°). ............ 88 Figure 65. Congaree River watershed is characterized by confluence of the Broad and Saluda ...

... 80.95764°). ................................ 101 Figure 75. Cary's Lake Dam breach on Sunday October 4, 2015: (a) Breach forming at location of left (eastern) spillway (exact time of photo remains to be determined as via Pinterest); (b) Fully formed breach at 12:07pm with significantly lowered reservoir level due to the downstream propagating dam break wave (photo: Gills Creek Watershed Association www.gillscreekwatershed.org; N 34.04866°, ...

... 3-dimensional view of the Cary's Lake Dam breach based on SfM- reconstruction from the octo-copter drone survey (N 34.04866°, W 80.95764°). ............. 112 Figure 85. Cary's Lake Dam breach in aerial views on October 7, 2015: (a) upstream (northward) view of the breached dam with intact right (western) spillway and empty Cary Lake bed in the background; (b) downstream (southward) view of the breached dam with intact right (western) spillway and Jackson Creek with the washed away Rockbridge Rd Bridge and Spring Lake in the background (photos from Gills Creek Watershed Association via: www.facebook.com/GillsCreekWatershedAssociation; ...

... 80.95195°). .................................. 125 Figure 95. Lower Rockyford Lake Dam: (a) Uncontrolled overflow concrete spillway washed- out under the bridge; (b) remains of concrete spillway scattered downstream in Gills Creek (photos: October 13, 2015; N 34.03595°, Figure 96. ...

... storm track of Hurricane Joaquin is shown in Figure 4 An upper atmospheric low-pressure system developed over the southeastern U.S. on 1 October drew a steady plume of upper-level moisture from Joaquin northwestward into South Carolina shown in Figure 5 and Figure 6. This moisture contributed to a multi-day rainfall event that caused historic flooding in that state's two largest cities of Charleston and Columbia. ...

... concrete dam breached directly to the north (left in flow direction) of the weir and spillway shown in Figure 49. The 10 m long breach is shown in Figure 50. Debris damming on the pedestrian steel bridge clogged the overflow area between the weir crest and the bridge reducing the spillway capacity (Figure 50). ...

... 10 m long breach is shown in Figure 50. Debris damming on the pedestrian steel bridge clogged the overflow area between the weir crest and the bridge reducing the spillway capacity (Figure 50). Ultimately the dam was overtopped as evidenced by the wrack deposited on the lateral tree stems at elevations above the dam crest ( Figure 50b). ...

... damming on the pedestrian steel bridge clogged the overflow area between the weir crest and the bridge reducing the spillway capacity (Figure 50). Ultimately the dam was overtopped as evidenced by the wrack deposited on the lateral tree stems at elevations above the dam crest ( Figure 50b). Hence debris damming of the spillway leading to overtopping are the cause of the dam breach at Gibsons Pond. ...

... reservoir water level was requested to be lowered by 5 m for the repair work and was empty at the time of last S.C.-DHEC inspection. The southern (right) dam abutment is formed by an outcrop of hard rock shown in Figure 55. The spillway consists of one large sluice gate, which was only lifted by 0.3 m or slightly opened at the time of the site visit, and two smaller openings which serve as emergency overflows into the spillway with a fixed weir crest. ...

... penstock had been partially excavated in September 2015 for repair work on the downstream side of the dam prior to the flooding event in October 2015. The intake to the penstock with the protecting trash rack and controlling vertical sluice gate is shown in Figure 57(a). The left stonemasonry wall directing flow to the intake is intact, while the right stonemasonry wall directing flow to the intake has been carried away by flood waters. ...

... left stonemasonry wall directing flow to the intake is intact, while the right stonemasonry wall directing flow to the intake has been carried away by flood waters. The dam failure exposed trapezoidal embankment profile of the earth fill dam on the southern (right) side of the breach shown in Figure 57(b). The dam consists of fairly homogeneous reddish sandy fill that most likely came from an area of the pond just upstream of the right abutment. ...

... dam consists of fairly homogeneous reddish sandy fill that most likely came from an area of the pond just upstream of the right abutment. Twelve-Mile Creek has eroded some of the upstream section of the dam and carved into the more resistant, tan saprolite foundation material shown in Figure 58(a). At the time of survey, the breach had a length of more than 31 m along the crest. ...

... the time of survey, the breach had a length of more than 31 m along the crest. Dam overtopping evidence was found in the form of wrack and rafted debris wrapped around trees on the dam crest shown in Figure 58(b). All along the downstream slope of the Old Mill Pond Dam, at the time of our reconnaissance visit, the vegetation was lying flat. ...

... along the downstream slope of the Old Mill Pond Dam, at the time of our reconnaissance visit, the vegetation was lying flat. The overtopping induced shooting discharge on the downstream slope caused scour holes and erosional features downstream of the brick tower built on the downstream slope shown in Figure 58(c). The wrack wrapped around trees, flat lying vegetation and erosional features on the downstream slope indicate that the dam had been completely overtopped along the entire crest length shown in Figure 59(a,b). ...

... overtopping induced shooting discharge on the downstream slope caused scour holes and erosional features downstream of the brick tower built on the downstream slope shown in Figure 58(c). The wrack wrapped around trees, flat lying vegetation and erosional features on the downstream slope indicate that the dam had been completely overtopped along the entire crest length shown in Figure 59(a,b). The overtopping and discharge through the dam breach overwhelmed the two box culverts under the US-1 highway shown in Figure 59(c). ...

... wrack wrapped around trees, flat lying vegetation and erosional features on the downstream slope indicate that the dam had been completely overtopped along the entire crest length shown in Figure 59(a,b). The overtopping and discharge through the dam breach overwhelmed the two box culverts under the US-1 highway shown in Figure 59(c). ...

... dam breached at the location of the left (eastern) spillway as shown in Figure 75(a) as the breach is forming in a photo without an exact time stamp. Overtopping occurred for a short period of time based on the debris at the tilted road marker sign near the center of the dam. ...

... solid concrete wall with small drainage openings on top of the bridge crossing the right spillway would limit initial overtopping at this location. The later photo uploaded at 12:07pm on October 4, 2015 by the Gills Creek Watershed Association shows a fully developed breach with a significantly lowered outflow water level shown in Figure 75(b). The water level continued to drop in the following hours with flood discharge through the breach and the right (western) spillway at 2:51pm shown in Figure 76. ...

... early reports of a Windsor Lake Dam failure turned out to be false. However, the small and unregulated Pine Tree Lake Dam located 0. This corresponds with the photo of the breach forming at the location of the smaller left spillway shown in Figure 75(a). Aerial views of Jackson Creek with the flushed out Cary's Lake upstream and the Rockbridge Road Bridge downstream of Cary's Lake Dam breach are shown in Figure 85. ...

... the small and unregulated Pine Tree Lake Dam located 0. This corresponds with the photo of the breach forming at the location of the smaller left spillway shown in Figure 75(a). Aerial views of Jackson Creek with the flushed out Cary's Lake upstream and the Rockbridge Road Bridge downstream of Cary's Lake Dam breach are shown in Figure 85. ...

... concrete spillway was completely washed out from under the bridge along with the underlying earth fill and abutment scouring as shown in Figure 94. The remains of the concrete spillway were scattered in the Gills Creek downstream of the bridge as shown in Figure 95. The discharge from Lower Rockyford Lake flows directly into Forest Lake, where it is joined by the waters from the tributary Jackson Creek. ...