Thermal and Optical Characteristics of Southern Indian Lake before, during, and after Impoundment and Churchill River Diversion
In 1976 Southern Indian Lake, a large, shallow, multibasin lake on the Churchill River in northern Manitoba, was impounded. The mean annual water level was raised 3 m over the historic mean level to divert 875 m 3 ∙s −1 by gravity flow from the lake into the Nelson River drainage. Five years of obse...
Published in: | Canadian Journal of Fisheries and Aquatic Sciences |
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1984
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crcansciencepubl:10.1139/f84-071 2023-12-17T10:28:51+01:00 Thermal and Optical Characteristics of Southern Indian Lake before, during, and after Impoundment and Churchill River Diversion Hecky, R. E. 1984 http://dx.doi.org/10.1139/f84-071 http://www.nrcresearchpress.com/doi/pdf/10.1139/f84-071 en eng Canadian Science Publishing http://www.nrcresearchpress.com/page/about/CorporateTextAndDataMining Canadian Journal of Fisheries and Aquatic Sciences volume 41, issue 4, page 579-590 ISSN 0706-652X 1205-7533 Aquatic Science Ecology, Evolution, Behavior and Systematics journal-article 1984 crcansciencepubl https://doi.org/10.1139/f84-071 2023-11-19T13:38:49Z In 1976 Southern Indian Lake, a large, shallow, multibasin lake on the Churchill River in northern Manitoba, was impounded. The mean annual water level was raised 3 m over the historic mean level to divert 875 m 3 ∙s −1 by gravity flow from the lake into the Nelson River drainage. Five years of observation beginning 2 yr before the year of impoundment and continuing for 2 yr after impoundment indicate that lake temperatures, light available for photosynthesis, and Secchi disk transparencies have all declined. Increased mean depths, loss of riverine heat input because of diversion, and radiative losses because of back-scattering from increased concentrations of suspended solids have caused a significant 1–2 °C cooling of the different basins of the lake and increased the natural south to north temperature gradient during the lake's heating period. Winter temperatures also decreased significantly in South Bay, the point of diversion, because of increased inflow from a cooler region, increases in light scattering caused by higher concentrations of suspended solids derived from shoreline erosion accounted for the most significant changes in vertical extinction coefficients and Secchi disk depths. Increased extinction of light and increased mean depth significantly reduced the mean water column light intensity of the mixed layer. These changes in the thermal and optical characteristics after impoundment occurred concurrently with significant changes in the impoundment's biological communities. Article in Journal/Newspaper Churchill Churchill River Nelson River Canadian Science Publishing (via Crossref) Indian South Bay ENVELOPE(-63.579,-63.579,-64.870,-64.870) Southern Indian Lake ENVELOPE(-98.500,-98.500,57.167,57.167) Canadian Journal of Fisheries and Aquatic Sciences 41 4 579 590 |
institution |
Open Polar |
collection |
Canadian Science Publishing (via Crossref) |
op_collection_id |
crcansciencepubl |
language |
English |
topic |
Aquatic Science Ecology, Evolution, Behavior and Systematics |
spellingShingle |
Aquatic Science Ecology, Evolution, Behavior and Systematics Hecky, R. E. Thermal and Optical Characteristics of Southern Indian Lake before, during, and after Impoundment and Churchill River Diversion |
topic_facet |
Aquatic Science Ecology, Evolution, Behavior and Systematics |
description |
In 1976 Southern Indian Lake, a large, shallow, multibasin lake on the Churchill River in northern Manitoba, was impounded. The mean annual water level was raised 3 m over the historic mean level to divert 875 m 3 ∙s −1 by gravity flow from the lake into the Nelson River drainage. Five years of observation beginning 2 yr before the year of impoundment and continuing for 2 yr after impoundment indicate that lake temperatures, light available for photosynthesis, and Secchi disk transparencies have all declined. Increased mean depths, loss of riverine heat input because of diversion, and radiative losses because of back-scattering from increased concentrations of suspended solids have caused a significant 1–2 °C cooling of the different basins of the lake and increased the natural south to north temperature gradient during the lake's heating period. Winter temperatures also decreased significantly in South Bay, the point of diversion, because of increased inflow from a cooler region, increases in light scattering caused by higher concentrations of suspended solids derived from shoreline erosion accounted for the most significant changes in vertical extinction coefficients and Secchi disk depths. Increased extinction of light and increased mean depth significantly reduced the mean water column light intensity of the mixed layer. These changes in the thermal and optical characteristics after impoundment occurred concurrently with significant changes in the impoundment's biological communities. |
format |
Article in Journal/Newspaper |
author |
Hecky, R. E. |
author_facet |
Hecky, R. E. |
author_sort |
Hecky, R. E. |
title |
Thermal and Optical Characteristics of Southern Indian Lake before, during, and after Impoundment and Churchill River Diversion |
title_short |
Thermal and Optical Characteristics of Southern Indian Lake before, during, and after Impoundment and Churchill River Diversion |
title_full |
Thermal and Optical Characteristics of Southern Indian Lake before, during, and after Impoundment and Churchill River Diversion |
title_fullStr |
Thermal and Optical Characteristics of Southern Indian Lake before, during, and after Impoundment and Churchill River Diversion |
title_full_unstemmed |
Thermal and Optical Characteristics of Southern Indian Lake before, during, and after Impoundment and Churchill River Diversion |
title_sort |
thermal and optical characteristics of southern indian lake before, during, and after impoundment and churchill river diversion |
publisher |
Canadian Science Publishing |
publishDate |
1984 |
url |
http://dx.doi.org/10.1139/f84-071 http://www.nrcresearchpress.com/doi/pdf/10.1139/f84-071 |
long_lat |
ENVELOPE(-63.579,-63.579,-64.870,-64.870) ENVELOPE(-98.500,-98.500,57.167,57.167) |
geographic |
Indian South Bay Southern Indian Lake |
geographic_facet |
Indian South Bay Southern Indian Lake |
genre |
Churchill Churchill River Nelson River |
genre_facet |
Churchill Churchill River Nelson River |
op_source |
Canadian Journal of Fisheries and Aquatic Sciences volume 41, issue 4, page 579-590 ISSN 0706-652X 1205-7533 |
op_rights |
http://www.nrcresearchpress.com/page/about/CorporateTextAndDataMining |
op_doi |
https://doi.org/10.1139/f84-071 |
container_title |
Canadian Journal of Fisheries and Aquatic Sciences |
container_volume |
41 |
container_issue |
4 |
container_start_page |
579 |
op_container_end_page |
590 |
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1785581056827588608 |