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| Titel |
Variability and trends in streamflow input to Hudson Bay, Canada |
| VerfasserIn |
Stephen Déry, Theodore Mlynowski, Marco Hernandez-Henriquez, Fiammetta Straneo |
| Konferenz |
EGU General Assembly 2010
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 12 (2010) |
| Datensatznummer |
250033391
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| Zusammenfassung |
| This presentation will explore the variability and trend in streamflow input to Hudson Bay
(including James Bay), Canada, over 1964-2008. Twenty-three rivers, spanning a maximum
gauged area of 2.53 Ã 106 km2, are chosen for this study. These rivers collectively transport
521 km3 of freshwater to Hudson Bay each year. Adjusting this value for the missing
contributing area yields a total annual freshwater flux of 762 km3 into Hudson Bay.
The standard deviation and coefficient of variation in annual streamflow input to
Hudson Bay reach 48.9 km3 and 0.09, respectively. The monotonic trend assessed
with a Kendall-Theil Robust Line shows no detectable (|signal-to-noise ratio| <
1) change in total discharge into Hudson Bay over 1964-2008; however, further
analyses reveal a detectable 16% decline in annual streamflow input to Hudson Bay for
1964-1989 followed by a detectable 26% increase over 1989-2008, marked by a
record discharge of 633 km3 in 2005. There is a notable shift in the seasonality of
Hudson Bay discharge over time, with a detectable positive (negative) trend in winter
(summer) streamflow from 1964 to 2008. Annual hydrographs for regulated and natural
rivers over two periods suggest these changes arise from the storage of water in
reservoirs during spring and summer that is later released for the generation of
hydroelectricity in fall and winter. The naturally-flowing rivers show a marked decline in
the variability of daily streamflow input to Hudson Bay in recent years while the
opposite trend is found in the regulated systems. The recent diversion of 19 km3
yr-1 or 71% of the annual streamflow from the Rupert River northward into La
Grande Rivière for enhanced power production will further exacerbate the streamflow
timing shifts observed in Hudson Bay. The talk will end with a brief discussion of
the potential impacts of flow regulation on the Hudson Bay marine environment. |
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