Water and solute export from the Yukon River and its tributaries
Dates
Year
2008
Citation
Frederick, Zanden Arthur, 2008, Water and solute export from the Yukon River and its tributaries: University of Colorado Boulder.
Summary
Annual export of major and trace solutes are determined for the Yukon River based on summing 42 tributary contributions. First we show that annual discharge of the Yukon River can be computed by summing calculated annual discharges from 42 tributaries using a previously published regional regression equation. Next, annual loads for 11 solutes are determined by combining annual discharge with point measurements of solute concentrations in tributary river water. Based on the sum of tributary contributions we find that the Yukon River discharges approximately 211 km super(3) yr super(-1) of water and 33 million metric tons of dissolved solids each year at Pilot Station, AK. Disch arged solutes are dominated by cations calcium and magnesium [...]
Summary
Annual export of major and trace solutes are determined for the Yukon River based on summing 42 tributary contributions. First we show that annual discharge of the Yukon River can be computed by summing calculated annual discharges from 42 tributaries using a previously published regional regression equation. Next, annual loads for 11 solutes are determined by combining annual discharge with point measurements of solute concentrations in tributary river water. Based on the sum of tributary contributions we find that the Yukon River discharges approximately 211 km super(3) yr super(-1) of water and 33 million metric tons of dissolved solids each year at Pilot Station, AK. Disch arged solutes are dominated by cations calcium and magnesium (5.66x10 super(12) and 1.42x10 super( 12) g yr super(-1)) and anions bicarbonate and sulfate (17.2x10 super(12) and 5.42x10 super(12) g yr super(-1). These loads compare well with loads calculated using the USGS computer program LOADEST based on five years of data at mainstem sites. These findings show that annual solute yields for a major subarctic river can be determined from tributary basin contributions based on calculated annual discharge and distributed point measurements of solute concentration. Chemical denudation rates within the Yukon River basin are determined by mass balance analysis of surface water chemistry. Feasible mineral weathering reactions are presented to determine the silicate and carbonate mineral weathering contribution to total cation denudation. Cation denudation rates among tributary rivers range between 0.9 and 26.3 t km super(-2) yr super(-1) for carbonate minerals and between 0.08 and 1.3 t km super(-2) yr super(-1) for silicate minerals. Tributaries draining mountainous landscapes tend to have the largest yields of carbonate weathering products while rivers draining lowlands and forested uplands have higher silicate cation denudation rates. For the mainstem locations, annual cation denudation rates average 0.46 and 8.54 t km super(-2) yr super(-1) for the silicate and carbonate mineral weathering fractions respectively. Denudation rates calculated here are in agreement with rates published elsewhere for the Yukon River mainstem, however these are the first known rates reported for most of the tributary rivers.
