5 refs; 5 figs; 3 appendices

A method is described for estimating specific 7-day mean low flow for catchments that are ungauged or have records which are inadequate for reliable flow frequency analysis. New Zealand has been divided into 11 regions and a regression equation for specific 5-year 7-day low flow(SQ57) is developed for each region. Nine of the eleven regions use one or more slope variables, eight use catchment mean annual rainfall as an independent variable and eight use one or more hydrogeology variables. The standard error of prediction for 9 out of 10 catchments is 40% less for all regions and less than 30% for nine of the eleven regions. A procedure for estimating ungauged SQ57 using the regression equations and for obtaining estimates for other periods, is given in an Appendix. (auth)