Lowes, A G; Southwell, Mark; Thoms, Martin

Author(s)

Lowes, A G

Southwell, Mark

Thoms, Martin

Publication Date

2008

Abstract

Dissolved nutrients are mobilised from flood plain surfaces during periods of inundation. These dissolved materials are an essential resource for the functioning of flood plain-river ecosystems. However, little is known of the dynamics of nutrient release during periods of flood plain inundation or the factors controlling their release. Patterns of total organic carbon (TOC), total nitrogen (TN) and total phosphorus (TP) released from flood plain sediments were investigated in this study. In a series of experiments conducted over a 72-h period, sediments collected from various flood plain surfaces were wetted in order to assess possible controls, spatial patterns, and the influence of changing hydrology on the release of dissolved nutrients. Top-down constraints, including the reach location, degree of confinement and elevation above the river bed, all had a significant impact on release rates for TOC, as well as release rates and concentrations of TN. Sediment texture was significantly associated with TP concentrations only; although sediment texture was associated with TN and TOC release rates over time. These results indicate that larger scale constraints, such as position in the broader riverine landscape, influence spatial patterns of nutrient release rates over time more than smaller scale influences such as sediment texture. Using the release data for the various flood plain surfaces, combined with long-term flow data for several flow scenarios, simple budgets for dissolved nutrients were calculated for the study reach over the 1922-2000 period. A 43% reduction in the potential supply of dissolved nutrients was demonstrated with changes in river hydrology over this 78-year period associated with water resource developments.

Citation

Sediment Dynamics in Changing Environments, p. 68-75

ISBN

9781901502848

Link

https://hdl.handle.net/1959.11/8339

Publisher

IAHS Press

Series

IAHS Publication

Title

Flood plain nutrient dynamics: patterns, controls and the influence of changing hydrology

Type of document

Conference Publication

Entity Type

Publication

Author(s)	Lowes, A G Southwell, Mark Thoms, Martin
Publication Date	2008
Abstract	Dissolved nutrients are mobilised from flood plain surfaces during periods of inundation. These dissolved materials are an essential resource for the functioning of flood plain-river ecosystems. However, little is known of the dynamics of nutrient release during periods of flood plain inundation or the factors controlling their release. Patterns of total organic carbon (TOC), total nitrogen (TN) and total phosphorus (TP) released from flood plain sediments were investigated in this study. In a series of experiments conducted over a 72-h period, sediments collected from various flood plain surfaces were wetted in order to assess possible controls, spatial patterns, and the influence of changing hydrology on the release of dissolved nutrients. Top-down constraints, including the reach location, degree of confinement and elevation above the river bed, all had a significant impact on release rates for TOC, as well as release rates and concentrations of TN. Sediment texture was significantly associated with TP concentrations only; although sediment texture was associated with TN and TOC release rates over time. These results indicate that larger scale constraints, such as position in the broader riverine landscape, influence spatial patterns of nutrient release rates over time more than smaller scale influences such as sediment texture. Using the release data for the various flood plain surfaces, combined with long-term flow data for several flow scenarios, simple budgets for dissolved nutrients were calculated for the study reach over the 1922-2000 period. A 43% reduction in the potential supply of dissolved nutrients was demonstrated with changes in river hydrology over this 78-year period associated with water resource developments.
Citation	Sediment Dynamics in Changing Environments, p. 68-75
ISBN	9781901502848
Link	https://hdl.handle.net/1959.11/8339
Publisher	IAHS Press
Series	IAHS Publication
Title	Flood plain nutrient dynamics: patterns, controls and the influence of changing hydrology
Type of document	Conference Publication
Entity Type	Publication

Flood plain nutrient dynamics: patterns, controls and the influence of changing hydrology

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