Algorithm for Adjusting Stream Stage Records

Quartic and cubic polynomials are proposed for filling in or correcting digital stream stage records by computer. Mathematical restraints are defined so that the polynomials produce estimated or corrected stage-time curves which are smoothly transitional from portions of good record. Correct stage and time at the beginning and end of a missing period and the slope of the stage-time curve at these points provide the essential data needed to determine a cubic equation for estimating a missing period. If, in addition, a correct intermediate stage-time point is known, a quartic is used for estimation. For correcting erroneous stage records, slope of the correction curve is considered to be zero at the beginning and end of the adjustment period. Thus, only beginning and ending corrections are required to determine a cubic for stage adjustment. If correction for some intermediate time is known, a quartic is used.