TY - JOUR
T1 - Post-dam sediment dynamics and processes in the Colorado River estuary
T2 - Implications for habitat restoration
AU - Zamora, Hector A.
AU - Nelson, Steven M.
AU - Flessa, Karl W.
AU - Nomura, Ritsuo
N1 - Funding Information:
This research was supported by a National Science Foundation Graduate Research Fellowship Grant ( DGE-1143953 ) to H.A.Z., NSF research grant EAR 044381 (Research Coordination Network: Colorado River delta) to K.W.F. and Christensen Fund Grant, Community-based restoration and monitoring of the Colorado River estuary, Mexico to K.W.F. We thank Jeanine Ash for her assistance in the field, the Sonoran Institute for their logistical support and two anonymous reviewers for their constructive criticism.
PY - 2013/10
Y1 - 2013/10
N2 - River-sea connectivity is essential for restoring ecosystem services in the Colorado River delta. The mixing of river water and seawater sustains biodiversity and provides brackish-water nursery grounds for both commercially important and endangered marine species. The Colorado River no longer reaches the sea except during particularly high tides and anomalously wet years. The river's relict channel is now obstructed by an accumulation of sediments deposited during flood tides; ebb flows are not strong enough to keep the channel open. Landsat 5-TM and Landsat-7 scenes from the Colorado River delta and tide prediction tables were used to reconstruct river-sea connectivity and geomorphic processes after 50 years of extensive human manipulation of the Colorado River. Historical documentation, previous topographic surveys and sediment cores were used to estimate sedimentation rates in the lower river channel. Satellite images and tide charts show that currently the river reaches the sea or the sea reaches the river about 12 days per year, unlike 10 years ago when a year-round connection existed. Reduction in connectivity results from the evolution of a tidal sandbar located within the bedload convergence zone, about 35. km upstream from the river's mouth. Historical documentation and sediment core analyses suggest sedimentation rates in the range of 10-21. cm per year. With the current conditions prevailing, active management - dredging - is required and needs to occur once every 5-10 years to reconnect the remaining riparian wetlands in the Colorado River to the Gulf of California.
AB - River-sea connectivity is essential for restoring ecosystem services in the Colorado River delta. The mixing of river water and seawater sustains biodiversity and provides brackish-water nursery grounds for both commercially important and endangered marine species. The Colorado River no longer reaches the sea except during particularly high tides and anomalously wet years. The river's relict channel is now obstructed by an accumulation of sediments deposited during flood tides; ebb flows are not strong enough to keep the channel open. Landsat 5-TM and Landsat-7 scenes from the Colorado River delta and tide prediction tables were used to reconstruct river-sea connectivity and geomorphic processes after 50 years of extensive human manipulation of the Colorado River. Historical documentation, previous topographic surveys and sediment cores were used to estimate sedimentation rates in the lower river channel. Satellite images and tide charts show that currently the river reaches the sea or the sea reaches the river about 12 days per year, unlike 10 years ago when a year-round connection existed. Reduction in connectivity results from the evolution of a tidal sandbar located within the bedload convergence zone, about 35. km upstream from the river's mouth. Historical documentation and sediment core analyses suggest sedimentation rates in the range of 10-21. cm per year. With the current conditions prevailing, active management - dredging - is required and needs to occur once every 5-10 years to reconnect the remaining riparian wetlands in the Colorado River to the Gulf of California.
KW - Colorado River delta, Mexico
KW - Estuarine restoration
KW - River-sea connectivity
KW - Sedimentation rates
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U2 - 10.1016/j.ecoleng.2012.11.012
DO - 10.1016/j.ecoleng.2012.11.012
M3 - Article
AN - SCOPUS:84884591085
VL - 59
SP - 134
EP - 143
JO - Ecological Engineering
JF - Ecological Engineering
SN - 0925-8574
ER -