Influence of Catchment and Stream Characteristics on Suspended Solids and Phosphorus Concentrations Across an agriculturally Intensive Watershed in Southern Ontario

Arsh Grewal

doi:10.32920/ryerson.14667957

Abstract

The overall objective of this study is to determine the influence of landscape and hydrological characteristics on sub-catchment variability of total phosphorus (TP), soluble reactive phosphorus (SRP), the ratio of SRP and TP (SRP/TP), and total suspended solids (TSS). Fourteen longitudinal synoptic surveys were conducted for 13 sampling sites over a variety of flow conditions in the Innisfil Creek watershed located in southern Ontario. The surveys were split into baseflow and stormflow and partial least squares regression (PLSR) was used to analyze the relationship between watershed and hydrological characteristics, median concentrations of phosphorus, and TSS. The PLSR models indicate that buried tile drainage might be a major source of SRP in Innisfil Creek, while bank erosion is likely a dominant source of TSS. The results of this study can serve as the basis for future adaptive management experiments that seek to improve water quality in Innisfil Creek and beyond.

Highlights

Introduction and Research ObjectivesAnthropogenic eutrophication is a major threat to the health of freshwater ecosystems (Conley et al, 2009; Dupas et al, 2015a; Monteagudo et al, 2012)
Concentrations for total phosphorus (TP), soluble reactive phosphorus (SRP), and total suspended solids (TSS) were significantly higher during stormflow for multiple sites (Figure 3), which seems to suggest that phosphorus and TSS increase in Innisfil Creek during storm events via flushing of sediments and decaying organic matter from surrounding fields and ditches
Concentrations for SRP along Innisfil Creek (i1 - i6) during stormflow were generally higher than other sites and decreased as one moved downstream

Summary

Introduction

Introduction and Research ObjectivesAnthropogenic eutrophication is a major threat to the health of freshwater ecosystems (Conley et al, 2009; Dupas et al, 2015a; Monteagudo et al, 2012). Algal blooms and increased growth of vascular plants can contribute to hypoxic conditions, leading to fish death and a decline in aquatic biodiversity (Kleinman et al, 2011; Monteagudo et al, 2012). In watersheds dominated by agriculture, phosphorus from fertilizer applications is often transported from source areas into streams via surface and subsurface runoff (Fuchs et al, 2009; Stutter et al, 2008). Algal blooms and increased growth of vascular plants can contribute to hypoxic conditions when they decay, leading to fish death and a decline in aquatic biodiversity (Kleinman et al, 2011; Monteagudo et al, 2012). In watersheds dominated by agriculture, phosphorus from fertilizer applications is often transported from source areas into streams via surface and subsurface runoff (Arheimer and Lide, 2000; Fuchs et al, 2009; Sharpley et al, 2008; Stutter et al, 2008). Soluble reactive phosphorus is an especially important phosphorus species because it is readily bioavailable for assimilation by organisms (Spivakov et al, 1999; Zhang et al, 2016)

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Discussion

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