A Comparison of Lab- and Field-Based Water Quality Measurements for Agricultural Surface Waters

Session: 42. - Multi-Watershed Nutrient Study: Establishing a Monitoring Network in Agricultural Regions

Kiana Zolfaghari, University of Waterloo, kzolfagh@uwaterloo.ca
Stephen Bird, Fluvial Systems Research Inc., sbird@fluvialsystemsresearch.com
Graham Wilkes, Agriculture and Agri-Food Canada, Graham.Wilkes@agr.gc.ca
Deanna Ellis, Agriculture and Agri-Food Canada, Deanna.Ellis@AGR.GC.CA
Katarina Pintar, Centre for Foodborne, Environmental, and Zoonotic Infectious Diseases, Public Health Agency of Canada, Ottawa, ON, Canada, Katarina.Pintar@phac-aspc.gc.ca
Natalie Gottschall, Agriculture and Agri-Food Canada, Natalie.Gottschall@agr.gc.ca
Ed Topp, Agriculture and Agri-Food Canada, ed.topp@agr.gc.ca
Claude Duguay, University of Waterloo, crduguay@uwaterloo.ca
Heather McNairn, Agriculture and Agri-Food Canada, heather.mcnairn@agr.gc.ca
David Lapen, Agriculture and Agri-Food Canada, david.lapen@canada.ca

Abstract

In situ measurements using a sonde instrument in the field are often relied upon for rapid water quality assessment, including for use in remote sensing of surface water quality. National scale investigations require an understanding of the behaviour of sonde measurements in differing environments for watershed comparison. We describe herein an assessment of sonde performance to measure water quality for use in national scale investigations. Multiple Yellow Spring Instrument (YSI EXO2) sondes were used to measure chlorophyll-a (chl-a), turbidity, and fluorescence dissolved organic matter (fDOM) within 4 watersheds in North America (i.e., the South Nation River, Grand River, Ausable-Bayfield River, and the Fraser River) in year 2015. Water samples were collected in tandem with sonde measurements at each site and were sent for laboratory analysis. The relationship between sonde-measured and filed-measured parameters improved when regression models were developed based on the dynamics of water optical properties, changing in both space and time. Results of this study demonstrate that the performance of sonde fluorometric sensors which measure chl-a and fDOM differ spatially and temporally, relative to laboratory results. Post field collection comparison of sonde data against laboratory results is suggested prior to using them further amongst and within regions of comparison.

1. Keyword
assessments

2. Keyword
comparison studies

3. Keyword
monitoring

4. Additional Keyword
Optical probes

5. Additional Keyword
Fluorometry

6. Additional Keyword
Calibration