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Leaves changing colors outside of Reston Town Center.

In this video we briefly discuss the removal of the Great Works Dam on the Penobscot River in Maine. We also highlight some work the USGS is doing to document river conditions before and after dam removal.

Permanent Site: L1 East Transect; Depth: 10.3 Meters (33.9 Feet); Distance from river mouth: 2.3 Kilometers (1.4 Miles) west; Pre/Post Dam Removal: 2 years post-dam removal; Lat/Long: 48.13957527,-123.59359993; Site Description: This transect is medium depth. Substrate is now mainly fine sediment/sand/mud covered in a layer of brown diatoms (0:09 seconds).

Permanent Site: L1 West Transect; Depth: 11.2 Meters (36.9 Feet); Distance from river mouth: 2.3 Kilometers (1.4 Miles) west; Pre/Post Dam Removal: 2 years post-dam removal; Lat/Long: 48.13957527,-123.59427175; Site Description: This transect is medium depth. The first 20 meters contains scattered boulders (0:08 seconds).

Permanent Site: H2 East Transect; Depth: 8.0 Meters (26.3 Feet); Distance from river mouth: 2.6 Kilometers (1.6 Miles) east; Pre/Post Dam Removal: 2 years post-dam removal; Lat/Long: 48.15008216,-123.53210661; Site Description: This site is medium to shallow depth.

Permanent Site: H2 West Transect; Depth: 7.4 Meters (24.3 Feet); Distance from river mouth: 2.6 Kilometers (1.6 Miles) east; Pre/Post Dam Removal: 2 years post-dam removal; Lat/Long: 48.15008216,-123.53277857; Site Description: This site is medium to shallow depth.

Permanent Control Site: GP1 East Transect; Depth: 7.2 Meters (23.5 Feet); Distance from river mouth: 19.0 Kilometers (11.8 Miles) east; Pre/Post Dam Removal: 2 years post-dam removal; Lat/Long: 48.11852521,-123.31538047; Site Description: This site was established as the eastern control. Depth is medium-shallow.

Permanent Control Site: GP2 East Transect; Depth: 13.0 Meters (42.8 Feet); Distance from river mouth: 18.8 Kilometers (11.7 Miles) east; Pre/Post Dam Removal: 2 years post-dam removal; Lat/Long: 48.12781102,-123.31645664; Site Description: This site was established as the eastern control. Substrate is mainly a gravel sand mixture.

In 1986, Congress directed the USGS to regularly report groundwater-level changes in the High Plains aquifer system. To comply with this directive, the USGS compares water levels measured every two years. By measuring water levels across the entire aquifer in one year, measurements made two years later enable calculation of changes over time.

Permanent Site: A2 West Transect; Depth: 12.9 Meters (Feet 42.3); Distance from river mouth: Kilometers 1.8 (1.1 Miles); Pre/Post Dam Removal: 2 years post-dam removal; Lat/Long: 48.14130295, -123.5883331; Site Description: One of our deeper sites at over 40 feet. Sediment is primarily sand/sandy mud with scattered boulders.

Permanent Site: D2 East Transect; Depth: 11.8 Meters (38.7 Feet); Distance from river mouth: 0.3 Kilometers (0.2 Miles); Pre/Post Dam Removal: 2 years post-dam removal; Lat/Long: 48.15233001,-123.56829403; Site Description: This site is right off the mouth of the river. Substrate is mainly gravel with some sand and cobble. No live seaweeds are present.

Permanent Site: D2 West Transect; Depth: 11.9 Meters (39.0 Feet); Distance from river mouth: 0.3 Kilometers (0.2 Miles); Pre/Post Dam Removal: 2 years post-dam removal; Lat/Long: 48.15233001,-123.56896603; Site Description: This site is right off the mouth of the river. Substrate is mainly gravel with some sand and cobble. Woody debris is seen (2:13 seconds).

Permanent Site: H1 East Transect; Depth: 5.4 Meters (Feet 17.8); Distance from river mouth: 2.4 Kilometers (1.5 Miles) east; Pre/Post Dam Removal: 2 years post-dam removal; Lat/Long: 48.1479177,-123.53472865; Site Description: This is a shallow site and one of the farthest removed from the effects of the sediment plume outside of the control sites.

Permanent Site: H1 West Transect; Depth: 5.9 Meters (Feet 19.2); Distance from river mouth: 2.4 Kilometers (1.5 Miles) east; Pre/Post Dam Removal: 2 years post-dam removal; Lat/Long: 48.14803012,-123.53535558; Site Description: This is a shallow site and one of the farthest removed from the effects of the sediment plume outside of the control sites.

Permanent Site: J1 East Transect; Depth: 9.1 Meters (30.0 Feet); Distance from river mouth: 6.7 Kilometers (4.1 Miles) east; Pre/Post Dam Removal: 2 years post-dam removal; Lat/Long: 48.13607725,-123.47935008; Site Description: This site is medium depth. Substrates has remained mainly a gravel/sand mixture. Seaweed density is still greatly decreased.

Permanent Site: J1 West Transect; Depth: 9.3 Meters (30.5 Feet); Distance from river mouth: 6.6 Kilometers (4.1 Miles) east; Pre/Post Dam Removal: 2 years post-dam removal; Lat/Long: 48.13607725,-123.48002186; Site Description: This site is medium depth. Substrates has remained mainly a gravel/sand mixture. Seaweed density is still greatly decreased.

Permanent Control Site: GP1 West Transect; Depth: 7.7 Meters (25.3 Feet); Distance from river mouth: 19.0 Kilometers (11.8 Miles) east; Pre/Post Dam Removal: 2 years post-dam removal; Lat/Long: 48.11852521,-123.31605203; Site Description: This site was established as the eastern control. Depth is medium-shallow.

Permanent Control Site: GP2 West Transect; Depth: 12.3 Meters (40.4 Feet); Distance from river mouth: 18.8 Kilometers (11.6 Miles) east; Pre/Post Dam Removal: 2 years post-dam removal; Lat/Long: 48.12781102,-123.31712832; Site Description: This site was established as the eastern control. Substrate is mainly a gravel/sand/cobble mixture surrounding boulders.

Permanent Site: E2 East Transect; Depth: 14.9 Meters (48.8 Feet); Distance from river mouth: 0.9 Kilometers (0.5 Miles) east; Pre/Post Dam Removal: 2 years post-dam removal; Lat/Long: 48.15653002,-123.56130401; Site Description: This is one of our deeper sites. Substrate is mainly gravel/cobble with an occasional boulder. Seaweed is absent.

Permanent Site: C2 East Transect; Depth: 15.9 Meters (Feet 52.2); Distance from river mouth: 0.7 Kilometers (0.4 Miles); Pre/Post Dam Removal: 2 years post-dam removal; Lat/Long: 48.147841,-123.57596074; Site Description: One of our deepest sites. Substrate is all muddy sand. Seaweed is absent.

Permanent Site: C2 West Transect; Depth: 16.8 Meters (Feet 55.1); Distance from river mouth: 0.7 Kilometers (0.5 Miles); Pre/Post Dam Removal: 2 years post-dam removal; Lat/Long: 48.147841,-123.57663268; Site Description: One of our deepest sites. Substrate is all muddy sand. Seaweed is absent.