Suspended sediment in a high-Arctic river:An appraisal of flux estimation methods

• Published in: Science of The Total Environment
• Main Authors: Ladegaard-Pedersen, Pernille, Sigsgaard, Charlotte, Kroon, Aart, Abermann, Jakob, Skov, Kirstine, Elberling, Bo
• Format: Article in Journal/Newspaper
• Language: English
• Published: 2017
• Subjects: Arctic river discharge; Annual suspended sediment flux; Q/h relation; Estimation methods; Extreme events; DISSOLVED ORGANIC-CARBON; TRACE-ELEMENT; METHODOLOGICAL CONSIDERATIONS; NORTHEAST GREENLAND; SAMPLING FREQUENCY; WATER DISCHARGE; NUTRIENT FLUXES; RATING CURVES; TRANSPORT; PERMAFROST; Arctic; Greenland; permafrost; Zackenberg
• Online Access: https://pure.au.dk/portal/da/publications/suspended-sediment-in-a-higharctic-river(a813c467-9b6d-4783-b57c-6f9f3511abba).html; https://doi.org/10.1016/j.scitotenv.2016.12.006

Quantifying fluxes of water, sediment and dissolved compounds through Arctic rivers is important for linking the glacial, terrestrial and marine ecosystems and to quantify the impact of a warming climate. The quantification of fluxes is not trivial. This study uses a 8-years data set (2005-2012) of daily measurements from the high-Artic Zackenberg River in Northeast Greenland to estimate annual suspended sediment fluxes based on four commonly used methods: M1) is the discharge weighted mean and uses direct measurements, while M2-M4) are one uncorrected and two bias corrected rating curves extrapolating a continuous concentration trace from measured values. All methods are tested on complete and reduced datasets. The average annual runoff in the period 2005-2012 was 190 +/- 25 mio center dot m(3) y(-1). The different estimation methods gave a range of average annual suspended sediment fluxes between 43,000 10,000 t y(-1) and 61,000 16,000 t y(-1). Extreme events with high discharges had a mean duration of 1 day. The average suspended sediment flux during extreme events was 17,000 +/- 5000 t y(-1), which constitutes a year-to-year variation of 20-37% of the total annual flux. The most accurate sampling strategy was bi-daily sampling together with a sampling frequency of 2 h during extreme events. The most consistent estimation method was an uncorrected rating curve of bi-daily measurements (M2), combined with a linear interpolation of extreme event fluxes. Sampling can be reduced to every fourth day, with both method-agreements and accuracies