Hydrology, Channel Morphology, and Holocene
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HYDROLOGY, CHANNEL MORPHOLOGY, AND HOLOCENE SEDIMENTATION RECORD OF THE CENTRAL PASSAIC RIVER BASIN, NJ by RACHEL MACKENZIE FILO A thesis submitted to the School of Graduate Studies Rutgers, The State University of New Jersey In partial fulfillment of the requirements For the degree of Master of Science Graduate Program in Geological Sciences Written under the direction of Dr. Gail M. Ashley And approved by New Brunswick, New Jersey October 2017 ABSTRACT OF THE THESIS Hydrology, Channel Morphology, and Holocene Sedimentation Record of the Central Passaic River Basin, NJ By RACHEL MACKENZIE FILO Thesis Director: Dr. Gail M. Ashley The Passaic River Basin, which spans 935 mi² over northern New Jersey and parts of New York, is defined by both its glacial and post-glacial history. The retreating ice sheet (~22-18 ka) created Glacial Lake Passaic, impounded behind the Watchung Mountains until a new outlet was opened at Little Falls. Glacial rerouted the Passaic River to a northeastward course, with wetlands developing on the glacial lake sediments. One such wetland, the Great Piece Meadows, covers 2,343 acres of undeveloped floodplain within the Central Basin. Three oxbows within these wetlands, named Oxbow2, RC, and TZS, were cored to determine the flooding and geomorphological history of the central Passaic’s floodplain. Radiocarbon dates and grain size data suggests that oxbow TZS was cut off from the main channel around 9-9.5 ka B.P., and that the ii Oxbow2 and RC were cut off around 3.6 B.P. These dates fall within a transition from a dry to a wet period during the Holocene, which may have been a cause for the avulsions. Using mercury soil concentrations, deposition from the past ~180 years were determined to be within the upper 5-17 cm of the cores. The Passaic’s central and lower basin have long been plagued by flooding problems, with the worst flood on record occurring in 1903. Analysis of peak discharge at gages along the Passaic and its tributaries for 27 major floods confirms observed flashy discharge of the tributaries and the backup of floodwaters from Little Falls to the central basin during flooding. While the Passaic Basin’s morphology makes it prone to flooding, there are anthropogenic factors as well. While peak discharges for major floods in the Passaic have decreased since the turn of the century, major flood frequency is increasing. Reservoirs are shown to significantly decrease annual runoff and flood discharge along rivers directly downstream from them, but while they can reduce the intensity of flooding, they do not prevent major floods. Annual average runoff ratio values have increase for most areas of the Passaic Basin’s streams as well, despite the construction of reservoirs and diversions for water supply. This implies that an increase in urban and suburban development is a factor in the river’s increasing flooding problems. iii ACKNOWLEDGEMENTS I would like to thank Gail Ashley, Scott Stanford, Ying Fan Reinfelder, the staff and students of Rutgers Department of Earth and Planetary Sciences, and the New Jersey Geological and Water Survey. I would also like to thank Chris Johnson, Kevin Garrett, Ted Pallis, Zachary Schagrin, Don Monteverde, and Jerry Delaney for their great help with fieldwork, as well as Mark Rapp from the NJ Natural Lands Trust. Thank you to Jim Browning and Gabe Gallegos for use of the core repository and help with the photo setup. I would also like to thank Marc Anderson, Robert Newton, and Smith College for the use of their lab and the Hydra C, Ben Horton for the use of his lab, and John Dooley for his help with the lab at NJGWS. Thank you to Amy Bottge for doing sieve grain size analysis and Isabel Hong and Tina Dura for their help with the Malvern. I would also like to thank Nicole Malerba for her assistance with making figures in Illustrator, and Ally Petriman, Michelle Kuhn, and Alex Carone for their help and support. I would like to thank my family for their support and assistance, with special thanks to Lindsey Filo for help with the figures in Illustrator. iv TABLE OF CONTENTS Abstract ............................................................................................................................ ii Acknowledgements ....................................................................................................... iv Introduction .................................................................................................................. 1 o Objectives ............................................................................................................ 5 o Hypothesis ............................................................................................................ 5 Geology .................................................................................................................. 6 o Bedrock Geology ............................................................................................... 6 o Surficial Geology .............................................................................................. 9 Glacial History ............................................................................................................ 13 o Glaciation and Glacial Lakes ......................................................................... 13 o Post Glacial Lakes ........................................................................................... 18 Geomorphology ........................................................................................................... 20 o The Passaic River and Tributaries ................................................................ 20 o River Gradients ............................................................................................... 25 Climate ............................................................................................................................ 28 o Holocene Climate ............................................................................................. 28 o Modern Climate ................................................................................................. 30 . Droughts ................................................................................................ 31 Human Settlement and Flooding Problems ........................................................... 31 o Effects of Urbanization on Watersheds .......................................................... 33 o Settlement and Land Use in the Passaic River Basin ................................... 34 . History ................................................................................................... 34 . Development and Population.............................................................. 37 Study Site Description ................................................................................................. 41 o The Great Piece Meadows ............................................................................... 40 o Oxbows ............................................................................................................... 44 Methods .......................................................................................................................... 47 o Field .................................................................................................................... 47 . Coring .................................................................................................... 47 Core Oxbow2 ........................................................................... 49 Core RC2 .................................................................................. 49 Core TZS2 ................................................................................ 51 o Laboratory .......................................................................................................... 53 . Grain Size .............................................................................................. 53 Wet Sieve and Pipette Analysis ............................................ 53 Malvern Sample Preparation ................................................. 53 . Radiocarbon Dating ............................................................................. 56 . Mercury ................................................................................................. 57 Sample Preparation ................................................................. 58 Analysis ................................................................................... 59 o Hydrology .......................................................................................................... 60 . Flood Hydrographs .............................................................................. 60 v Results ............................................................................................................................. 64 o Chronology......................................................................................................... 64 . Radiocarbon Dating ............................................................................. 64 . Mercury Concentrations ...................................................................... 67 o Core TZS2 ......................................................................................................... 68 . Stratigraphy ........................................................................................... 68 . Grain Size .............................................................................................