Spatial representation of in-stream sediment phosphorus release combining channel network approaches and in-situ experiments

Stutter, M. and Richards, S. and Ibiyemi, A. and Watson, H. (2021) Spatial representation of in-stream sediment phosphorus release combining channel network approaches and in-situ experiments. Science of the Total Environment, 795. ISSN 0048-9697

Full text not available from this repository.


Impairment of rivers by elevated phosphorus (P) concentration is an issue often studied at outlets of mesoscale catchments. Our objective was to evaluate within-catchment spatio-temporal processes along connected reaches to understand processes of internal P loading associated with sediment input, accumulations in channels and sediment-water column P exchange. Our overall hypothesis was that heterogeneous sediment residence within the channel of a 52 km2 mixed land cover catchment resulted in key zones for sediment-water P exchange. We evaluated the channel network through ground-survey, spatial data methods establishing connectivity and energy gradients. This gave a background to understand sampling of sediments and P release/uptake to the water column using 90 s in-situ resuspension isolating a portion of streambed over five sets of three-location transects in May (spring storms, recent active erosion) and September (summer low flow, longer sediment residence). Simple transect position models (top, mid, bottom) predicted increased sediment resuspension yields and P contents in lower settings. Sediment P release following resuspension were mean (and range) 0.5 (−0.8 to 1.8) and 0.5 (−2.5 to 3.6) mg soluble reactive P/m2 bed in May and September, respectively, strengthening generally down the transects but inconsistently. Relationships (log form) showed a steepening rise in fine sediments, P content, background and disturbance-released dissolved P, with specific stream power < 40 W/m2. In-situ methods showed sediments dominantly (12 cases May, 13 cases Sep) as P sources capable of influencing dissolved P concentrations and with potential explanation that heterogeneous locations of internal P loading influence the systems longer-term observed P trends. Combining channel network, stream power assessment and in-situ sorption studies improved the understanding of influential zones of sediment-water P exchange within this mesoscale catchment. Such methods have potential to inform P model development and management.

Item Type:
Journal Article
Journal or Publication Title:
Science of the Total Environment
Uncontrolled Keywords:
ID Code:
Deposited By:
Deposited On:
21 Mar 2022 16:40
Last Modified:
17 Sep 2023 03:05