DOI: 10.5061/dryad.qnk98sfcp
title: Eklutna River Aquatic Habitat Monitoring, 2019

description: In collaboration with The Conservation Fund, Eklutna, Inc. completed
 deconstruction of the 60-foot high lower Eklutna River Dam in 2018. The
 deconstruction project was permitted, in part by the United States Army
 Corps of Engineers (USACE) which required Eklutna Inc. to collect a suite
 of pre- and post-project geomorphic and water quality data. These data
 were necessary to evaluate secondary effects of dam removal and sediment
 mobilization on the physical characteristics of the lower river for three
 years following dam removal. During Autumn of 2017, baseline data were
 collected describing channel geometry, substrate composition, and water
 quality at three monitoring locations downstream from the dam site. Year 1
 (2018) of this monitoring project was completed by Eklutna Inc. in
 collaboration with the National Oceanographic and Atmospheric
 Administration (NOAA), the Native Village of Eklutna, and the Alaska
 Department of Fish and Game (ADF&G)–Habitat. In 2019, Eklutna Inc.
 contracted with the ADF&G–Habitat to complete the final two years
 of USACE required monitoring. ADF&G Document Citation:
 Kirsch, J. M. and R. Benkert. 2019. Eklutna River aquatic habitat
 monitoring, 2019. Alaska Department of Fish and Game, Technical Report No.
 19-13, Palmer, AK. We conducted two sampling events during 2019, visiting
 four previously established monitoring locations. Two of these monitoring
 locations were downstream from the deconstructed dam site but upstream
 from the Thunder Bird Creek confluence; one site was downstream from
 Thunder Bird Creek; and one site was above the sediment plug upstream from
 the dam site. At each of the three lower sites, a suite of variables
 including channel geometry, substrate composition, and water quality were
 recorded. Continuous water temperature monitoring sites were established
 at two of these three locations. At the one site upstream from the dam
 site, only water quality variables were recorded in addition to the
 establishment of a third continuous temperature monitoring location. At
 the two monitoring sites upstream from the Thunder Bird Creek confluence,
 channel geometry measurements indicated aggradation occurred following dam
 deconstruction. Dominant substrates generally transitioned from silt/sand
 and cobble prior to dam deconstruction to mostly medium gravel dominance
 with the D50 particle size generally increasing, and D84 particle size
 generally decreasing. Water quality at these two sites were generally
 within expected ranges; however, pH was consistently high, ranging from
 8.44 to 8.70. All recorded variables from the monitoring site downstream
 from the Thunder Bird Creek confluence generally remained unchanged. At
 the water quality sampling location upstream from the sediment plug, all
 variables were found to be within expected range. Interestingly, pH was
 again high; however, it tracked closely to measurements taken at each of
 the other monitoring sites.  
description: During Autumn of 2017, baseline data were collected describing
 channel geometry, substrate composition, and water quality at three
 monitoring locations downstream from the dam site. Year 1 (2018) of this
 monitoring project was completed by Eklutna Inc. in collaboration with the
 National Oceanographic and Atmospheric Administration (NOAA), the Native
 Village of Eklutna, and the Alaska Department of Fish and Game
 (ADF&G)–Habitat. In 2019, Eklutna Inc. contracted with the
 ADF&G–Habitat to complete the final two years of USACE required
 monitoring. We conducted two sampling events during
 2019, visiting four previously established monitoring locations. Two of
 these monitoring locations were downstream from the deconstructed dam site
 but upstream from the Thunder Bird Creek confluence; one site was
 downstream from Thunder Bird Creek; and one site was above the sediment
 plug upstream from the dam site. At each of the three lower sites, a suite
 of variables including channel geometry, substrate composition, and water
 quality were recorded. Continuous water temperature monitoring sites were
 established at two of these three locations. At the one site upstream from
 the dam site, only water quality variables were recorded in addition to
 the establishment of a third continuous temperature monitoring
 location. <br> At the two monitoring sites
 upstream from the Thunder Bird Creek confluence, channel geometry
 measurements indicated aggradation occurred following dam deconstruction.
 Dominant substrates generally transitioned from silt/sand and cobble prior
 to dam deconstruction to mostly medium gravel dominance with the D50
 particle size generally increasing, and D84 particle size generally
 decreasing. Water quality at these two sites were generally within
 expected ranges; however, pH was consistently high, ranging from 8.44 to
 8.70.