Transposition of Monthly Streamflow Data to Ungauged Catchments

Various forms of the regressional relationship between the concurrent monthly discharges of neighbouring catchments are explored, with a view to generalising the relationship for a region. This enables monthly streamflow data to be transposed from a gauged catchment to an ungauged catchment, provided that certain transfer coefficients can be estimated from the physical catchment and rainfall characteristics. Most of the methods are based on a linear relationship between the concurrent monthly discharges of a pair of catchments with only one transfer coefficient. This may be estimated in a number of ways for a pair of gauged-ungauged catchments, however, errors in the individual transposed flows are high.