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Stream temperature variation in regulated rivers: Evidence for a spatial pattern in daily minimum and maximum magnitudes
Author(s) -
Lowney Cynthia L.
Publication year - 2000
Publication title -
water resources research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.863
H-Index - 217
eISSN - 1944-7973
pISSN - 0043-1397
DOI - 10.1029/2000wr900142
Subject(s) - diurnal temperature variation , thermocline , spatial variability , hydrology (agriculture) , environmental science , variation (astronomy) , upstream and downstream (dna) , seasonality , atmospheric sciences , geology , upstream (networking) , climatology , ecology , physics , biology , geotechnical engineering , computer network , computer science , statistics , mathematics , astrophysics
Elevated water temperatures have become an important concern in watersheds where aquatic species such as salmonids are present. To maintain cold water downstream of large reservoirs, releases sometimes are taken from beneath the thermocline where water temperature exhibits little diurnal variation. This unusual upstream boundary condition, that is, steady flow and temperature, causes a characteristic pattern of “nodes” of minimum diurnal variation and “antinodes” of maximum diurnal variation to form at regular intervals downstream of the regulating reservoir. Within this paper, an analytical model is derived in order to illustrate the phenomenon of nodes and antinodes. Field data as well as analytical and numerical model simulations illustrate the formation of nodes and antinodes over a 250 km reach of the Sacramento River, located in the Central Valley of California.