Computation of Inflows and Outflows of Eight Regulated Lakes in the Oswego River Basin, New York, 1930-79

Abstract

Estimates of daily inflows and outflows of eight regulated lakes in the Oswego River basin and discharges of three rivers draining these lakes were computed and compiled for use in evaluated lake-regulation procedures in the basin 's stream and reservoir system and are stored on computer. This report includes a table of monthly flows at these sites from 1930-79. Computations were based on records from the 1930-79 water years. Daily net inflow estimates (lake inflow minus evaporation and possible groundwater seepage) were computed from the outflows and changes in lake storage. Lake storage was estimated from lake level data and elevation-capacity curves for each lake. A smoothing technique was applied to plots of daily lake levels before net inflows were computed. Where lake level or outflow data were missing, net flows were estimated from linear regression equations. Analysis of results indicates that: (1) smoothing the plots of daily lake levels significantly reduces random fluctuations resulting from seiche or wind action; (2) continuous lake storage recorders provide a more reliable record than staff gages (once-daily, lake level readings) for computing daily changes in lake storage; and (3) the effect of smoothing decreases as the computational period is increased. (USGS)