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The empirical fit of an annual harmonic function to stream temperature measurements in central New England can be improved by considering a harmonic period of less than 365 days instead of 365 or 366 days. Generalized equations, developed using periodic temperature data from 27 streamflow stations, allow predictions of stream temperature at any site given (1) the mean basin altitude (E), in meters above mean sea level, and (2) station latitude (LAT), in degrees. Stream temperature t, in degrees Celsius, on day number d, in days starting with January 1, is estimated as: ( F ( d -2 0 9 ) ) ] , when/d-Z09/TI2 t(d) = in which, M = 31.48 -0.0025 (E) -0.4635 (LAT) with standard error of estimate of 0.62OC, and T= 1228.88 -21.01 (LAT) with standard error of estimate of 14.1 days. (KEY TERMS: water temperature; harmonic analysis; Fourier analysis; central New England; regional analysis; water quality) Paper No. 74064 of the Water Resources Bulletin. Discussions are open until June 1, 1975. 'Hydrologists, U.S. Geological Survey, Boston, Massachusetts.

Major changes in hydrologic regime and morphology of channels of the Platte River and its major tributaries, the South Platte River and North Platte River in Colorado, Wyoming, and Nebraska have occurred since about 1860, when the water resources of the basin began to be developed for agriculture, municipal, and industrial uses. The extent of this water development, which continues to increase with growth in population and land use, has affected the timing of streamflow and transport of fluvial sediment in the Platte River through diversions, reservoir storage, and increased use of groundwater. Changes in flow regime, such as increase in low-flow magnitudes and abatement of peak-flow magnitudes, have made the riverine environment conducive to vegetative growth while reducing channel scour. These factors, in turn, contribute to morphologic changes of decreased channel width and channel area and increased island formation. This paper will focus on these trends over the last several decades in the study area on the Platte River in Nebraska.

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