The role of riparian vegetation density, channel orientation and water velocity in determining river temperature dynamics

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@article{37b112a4aa0545f58182dbfaf3340d65,
title = "The role of riparian vegetation density, channel orientation and water velocity in determining river temperature dynamics",
abstract = "A simulation experiment was used to understand the importance of riparian vegetation density, channel orientation and flow velocity for stream energy budgets and river temperature dynamics. Water temperature and meteorological observations were obtained in addition to hemispherical photographs along a ∼1 km reach of the Girnock Burn, a tributary of the Aberdeenshire Dee, Scotland. Data from nine hemispherical images (representing different uniform canopy density scenarios) were used to parameterise a deterministic net radiation model and simulate radiative fluxes. For each vegetation scenario, the effects of eight channel orientations were investigated by changing the position of north at 45° intervals in each hemispheric image. Simulated radiative fluxes and observed turbulent fluxes drove a high-resolution water temperature model for the reach. Simulations were performed under low and high water velocity scenarios. Both velocity scenarios yielded decreases in mean (≥ 1.6 °C) and maximum (≥ 3.0 °C) temperature as canopy density increased. Slow-flowing water resided longer within the reach, which enhanced heat accumulation and dissipation and drove higher maximum and lower minimum temperatures. Intermediate levels of shade produced highly variable energy flux and water temperature dynamics depending on the channel orientation and thus the time of day when the channel was shaded. We demonstrate that in many reaches relatively sparse but strategically located vegetation could produce substantial reductions in maximum temperature and suggest that these criteria are used to inform future river management.",
keywords = "Energy budget, Landuse change, Riparian forest, Riparian vegetation, River temperature, Stream temperature",
author = "Grace Garner and Malcolm, {Iain A.} and Sadler, {Jonathan P.} and Hannah, {David M.}",
year = "2017",
month = oct,
doi = "10.1016/j.jhydrol.2017.03.024",
language = "English",
volume = "553",
pages = "471--485",
journal = "Journal of Hydrology",
issn = "0022-1694",
publisher = "Elsevier",

}

RIS

TY - JOUR

T1 - The role of riparian vegetation density, channel orientation and water velocity in determining river temperature dynamics

AU - Garner, Grace

AU - Malcolm, Iain A.

AU - Sadler, Jonathan P.

AU - Hannah, David M.

PY - 2017/10

Y1 - 2017/10

N2 - A simulation experiment was used to understand the importance of riparian vegetation density, channel orientation and flow velocity for stream energy budgets and river temperature dynamics. Water temperature and meteorological observations were obtained in addition to hemispherical photographs along a ∼1 km reach of the Girnock Burn, a tributary of the Aberdeenshire Dee, Scotland. Data from nine hemispherical images (representing different uniform canopy density scenarios) were used to parameterise a deterministic net radiation model and simulate radiative fluxes. For each vegetation scenario, the effects of eight channel orientations were investigated by changing the position of north at 45° intervals in each hemispheric image. Simulated radiative fluxes and observed turbulent fluxes drove a high-resolution water temperature model for the reach. Simulations were performed under low and high water velocity scenarios. Both velocity scenarios yielded decreases in mean (≥ 1.6 °C) and maximum (≥ 3.0 °C) temperature as canopy density increased. Slow-flowing water resided longer within the reach, which enhanced heat accumulation and dissipation and drove higher maximum and lower minimum temperatures. Intermediate levels of shade produced highly variable energy flux and water temperature dynamics depending on the channel orientation and thus the time of day when the channel was shaded. We demonstrate that in many reaches relatively sparse but strategically located vegetation could produce substantial reductions in maximum temperature and suggest that these criteria are used to inform future river management.

AB - A simulation experiment was used to understand the importance of riparian vegetation density, channel orientation and flow velocity for stream energy budgets and river temperature dynamics. Water temperature and meteorological observations were obtained in addition to hemispherical photographs along a ∼1 km reach of the Girnock Burn, a tributary of the Aberdeenshire Dee, Scotland. Data from nine hemispherical images (representing different uniform canopy density scenarios) were used to parameterise a deterministic net radiation model and simulate radiative fluxes. For each vegetation scenario, the effects of eight channel orientations were investigated by changing the position of north at 45° intervals in each hemispheric image. Simulated radiative fluxes and observed turbulent fluxes drove a high-resolution water temperature model for the reach. Simulations were performed under low and high water velocity scenarios. Both velocity scenarios yielded decreases in mean (≥ 1.6 °C) and maximum (≥ 3.0 °C) temperature as canopy density increased. Slow-flowing water resided longer within the reach, which enhanced heat accumulation and dissipation and drove higher maximum and lower minimum temperatures. Intermediate levels of shade produced highly variable energy flux and water temperature dynamics depending on the channel orientation and thus the time of day when the channel was shaded. We demonstrate that in many reaches relatively sparse but strategically located vegetation could produce substantial reductions in maximum temperature and suggest that these criteria are used to inform future river management.

KW - Energy budget

KW - Landuse change

KW - Riparian forest

KW - Riparian vegetation

KW - River temperature

KW - Stream temperature

UR - http://www.scopus.com/inward/record.url?scp=85028360685&partnerID=8YFLogxK

U2 - 10.1016/j.jhydrol.2017.03.024

DO - 10.1016/j.jhydrol.2017.03.024

M3 - Article

VL - 553

SP - 471

EP - 485

JO - Journal of Hydrology

JF - Journal of Hydrology

SN - 0022-1694

ER -