Evaluating diffuse and point source phosphorus inputs to streams in a cold climate region using a Load Apportionment Model

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Language of the publication
English
Date
2021-06-02
Type
Accepted manuscript
Author(s)
  • Rattan, K. J.
  • Bowes, M. J.
  • Yates, A. G.
  • Culp, J. M.
  • Chambers, P. A.
Publisher
ScienceDirect

Abstract

Variation in the timing and quantity of diffuse versus point-source inputs of phosphorus (P) to streams can be evaluated by examining P concentration-flow relationships. Diffuse load inputs usually increase with stream flow (due to increased delivery caused by precipitation), whereas point-source concentrations decrease with rising river flow (due to increased dilution). This study tested the suitability of a load apportionment model (LAM), a power-law function of flow, to estimate contributions of diffuse and point inputs to P loads for eight sub- watersheds in the Red River Valley, a cold-climate rural region of Manitoba, Canada. For all but two sub-watersheds, annual and seasonal (snowmelt and summer) models of P concentration versus flow best fit a strictly diffuse source contribution. The models identified significant point-source inputs (in addition to diffuse sources) to two sub-watersheds, during summer to both watersheds (consistent with the fact that wastewater from sewage lagoons is discharged to upstream reaches between June and September) and during snowmelt for one watershed. Application of a LAM proved to be a simple and rapid method for nutrient source apportionment, and detection of unknown sources, for cold-climate rural sub-watersheds. Such information is critical for developing the most effective mitigation strategies to reduce P concentrations and eutrophication risk.

Plain language summary

Variation in the timing and quantity of non point and point source inputs of phosphorus (P) to streams can be evaluated by using P concentration – flow relationships. This study tested the suitability of a load apportionment model, a power-law function of flow, to estimate contributions of diffuse and point inputs to P loads for eight sub-watersheds in the Red River Valley, a cold-climate rural region of Manitoba, Canada. The models identified significant point-source inputs during summer to both watersheds and during snowmelt for one watershed.

Subject

  • Nature and environment,
  • Water,
  • Science and technology

Rights

Pagination

35 pages

Peer review

Yes

Open access level

Green

Identifiers

ISSN
2773-0719
0380-1330

Article

Journal title
Journal of Great Lakes Research
Journal volume
47
Journal issue
3
Accepted date
2020-05-06
Submitted date
2019-11-21

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Collection(s)

Water

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