1 appendix; 10 figs Available from Technical Information Office, Water and Soil Division, Ministry of Works and Development, PO Box 12041, Wellington

The Ministry of Works has established a network of experimental basins to study the hydrological characteristics of important soil-vegetation complexes of New Zealand. The effect of cultural changes on these characteristics has also been studied. The Puketurua Experimental Basin, situated on the Northland Peninsula 20 miles north-west of Whangarei is the catchment of the Puketurua Stream which discharges into the Aponga Stream. This project was carried out to research the northern yellow-brown earth/scrub, and the Northern yellow-brown earth/introduced grasses soil-vegetation complexes. The effect of a change in land use (scrub versus introduced grasses) and of a subsequent change in land management (introduction of graded banks) on the hydrological regime was found by studying hydrological characteristic and using mathematical models. Techniques of observing and analysing data were improved