Multiscale Hyporheic Exchange Through Strongly Heterogeneous Sediments

Bibliographic Details
Main Author:	Pryshlak, Timothy Theodozij
Language:	English
Published:	The Ohio State University / OhioLINK 2015
Subjects:	Hydrology Geology Hyporheic Zone hyporheic exchange hydraulic conductivity heterogeneity surface water-groundwater exchange
Online Access:	http://rave.ohiolink.edu/etdc/view?acc_num=osu1429803457

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spelling	ndltd-OhioLink-oai-etd.ohiolink.edu-osu14298034572021-08-03T06:30:45Z Multiscale Hyporheic Exchange Through Strongly Heterogeneous Sediments Pryshlak, Timothy Theodozij Hydrology Geology Hyporheic Zone hyporheic exchange hydraulic conductivity heterogeneity surface water-groundwater exchange Hydraulic conductivity (K) heterogeneity and channel morphology both control surface water-groundwater exchange (hyporheic exchange), which influences stream ecosystem processes and biogeochemical cycles. Here I show that K heterogeneity is the dominant control on exchange rates, residence times, and patterns in hyporheic zones with sharp lithologic contrasts. I simulated hyporheic exchange in a representative low-gradient stream with 300 different bimodal K fields composed of sand and silt. K realizations span five sets of sand-silt ratios and two sets of low and high K contrasts (one and three orders of magnitude). K heterogeneity increases interfacial fluxes by orders of magnitude relative to homogeneous cases, drastically changes the shape of residence time distributions, and decreases median residence times. The positioning of highly permeable sand bodies controls patterns of interfacial flux and flow paths. These results are remarkably different from previous studies of smooth, continuous K fields that indicate only moderate effects on hyporheic exchange. The results also show that hyporheic residence times are least predictable when sand body connectivity is low. As sand body connectivity increases, the expected residence time distribution (ensemble average for a given sand-silt ratio) remains approximately constant, but the uncertainty around the expectation decreases. Including strong heterogeneity in hyporheic models is imperative for understanding hyporheic fluxes and solute transport. In streams with bimodal sediments, characterizing stark facies contrasts is more critical for predicting hyporheic exchange metrics than characterizing channel morphology. 2015-05-20 English text The Ohio State University / OhioLINK http://rave.ohiolink.edu/etdc/view?acc_num=osu1429803457 http://rave.ohiolink.edu/etdc/view?acc_num=osu1429803457 unrestricted This thesis or dissertation is protected by copyright: all rights reserved. It may not be copied or redistributed beyond the terms of applicable copyright laws.
collection	NDLTD
language	English
sources	NDLTD
topic	Hydrology Geology Hyporheic Zone hyporheic exchange hydraulic conductivity heterogeneity surface water-groundwater exchange
spellingShingle	Hydrology Geology Hyporheic Zone hyporheic exchange hydraulic conductivity heterogeneity surface water-groundwater exchange Pryshlak, Timothy Theodozij Multiscale Hyporheic Exchange Through Strongly Heterogeneous Sediments
author	Pryshlak, Timothy Theodozij
author_facet	Pryshlak, Timothy Theodozij
author_sort	Pryshlak, Timothy Theodozij
title	Multiscale Hyporheic Exchange Through Strongly Heterogeneous Sediments
title_short	Multiscale Hyporheic Exchange Through Strongly Heterogeneous Sediments
title_full	Multiscale Hyporheic Exchange Through Strongly Heterogeneous Sediments
title_fullStr	Multiscale Hyporheic Exchange Through Strongly Heterogeneous Sediments
title_full_unstemmed	Multiscale Hyporheic Exchange Through Strongly Heterogeneous Sediments
title_sort	multiscale hyporheic exchange through strongly heterogeneous sediments
publisher	The Ohio State University / OhioLINK
publishDate	2015
url	http://rave.ohiolink.edu/etdc/view?acc_num=osu1429803457
work_keys_str_mv	AT pryshlaktimothytheodozij multiscalehyporheicexchangethroughstronglyheterogeneoussediments
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Multiscale Hyporheic Exchange Through Strongly Heterogeneous Sediments

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