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The use of invertebrate indicators for ecological resiliency evaluation of a flow regulated river. Research technical report, B-049-IDA Item Info

A systems approach was used to determine certain biological and physical indicators which were used to characterize the benthic ecosystem in the Clearwater River below Dworshak Dam, Idaho. Using these indicators, a Hectare-Day Index was developed that resulted in a quantitative measure of impact of regulated flow on the benthic system. For three selected periods, Summer 1978, Fall 1978 and Spring 1981 the reduction in the Hectare-Days Index when compared to an idealized constant flow for the same period was: 3.1 percent for the spring period, 5.5 percent for the fall period. The analysis of field tests over the period 1977 through 1980 indicated mean insect density and species richness decreased as depth increased from less than 60 to greater than 300 cm; the density and richness increased from velocities of less than 6 cm-sec to 60 cm-sec in the Clearwater River, where cobbles, boulders, and sand represented over 95 percent of the dominant particle sizes among the various habitats. The rate of insect colonization on a sterile substrate was used to predict carrying capacity for the main stem Clearwater River. Sixty days was the predicted time required to attain full carrying capacity in the regulated reach. By point of contrast, 47 days were required for the unregulated reach of the Middle Fork.

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Title:
The use of invertebrate indicators for ecological resiliency evaluation of a flow regulated river. Research technical report, B-049-IDA
Authors:
Haber, Donald F.; Bruvsen, Merlyn A.
Date Created (ISO Standard):
1982-12
Description:
A systems approach was used to determine certain biological and physical indicators which were used to characterize the benthic ecosystem in the Clearwater River below Dworshak Dam, Idaho. Using these indicators, a Hectare-Day Index was developed that resulted in a quantitative measure of impact of regulated flow on the benthic system. For three selected periods, Summer 1978, Fall 1978 and Spring 1981 the reduction in the Hectare-Days Index when compared to an idealized constant flow for the same period was: 3.1 percent for the spring period, 5.5 percent for the fall period. The analysis of field tests over the period 1977 through 1980 indicated mean insect density and species richness decreased as depth increased from less than 60 to greater than 300 cm; the density and richness increased from velocities of less than 6 cm-sec to 60 cm-sec in the Clearwater River, where cobbles, boulders, and sand represented over 95 percent of the dominant particle sizes among the various habitats. The rate of insect colonization on a sterile substrate was used to predict carrying capacity for the main stem Clearwater River. Sixty days was the predicted time required to attain full carrying capacity in the regulated reach. By point of contrast, 47 days were required for the unregulated reach of the Middle Fork.
Subjects:
Bioindicators Benthic environment Indicators Flow Substrates Carrying capacity Invertebrates
Collection:
IWRRI
IWRRI number:
198206
Rights:
Rights to the digital resource are held by the University of Idaho. http://www.uidaho.edu/
Publisher:
Idaho Water and Energy Resources Research Institute; University of Idaho
Contributing Institution:
University of Idaho
Type:
Text
Format:
application/pdf
Cataloger:
KIT
Date Digitized:
2017-08-22

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Preferred Citation:
"The use of invertebrate indicators for ecological resiliency evaluation of a flow regulated river. Research technical report, B-049-IDA", Idaho Waters Digital Library, University of Idaho Library Digital Collections, https://www.lib.uidaho.edu/digital/iwdl/items/iwdl-198206.html
Rights
Rights:
Rights to the digital resource are held by the University of Idaho. http://www.uidaho.edu/
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