Coastal Water Supplies Nambucca. Underground Water Wyong Shire. Underground Water in the Cassilis Merriwa Area

Abstract

Report No 21 Coastal Water Supplies Nambucca Underground Water Wyong Shire Underground Water in the CassilisMerriwa Area 1964

A geohydrological investigation of the eastern section of the Wyong Shire has shown that at least 250 feet of hard rock exists between the Wallarah Seam and the base of the alluvium. This thickness should be sufficient to allow the extraction of coal under Munmorah and Tuggerah Lakes

A brief investigation was made in the Cassilis district in order to assess the underground water resources. The geological formations in the area are; Quaternary - unconsolidated sedi ments, Tertiary - olivine basalt-flows and Jurassic-sandstone and shale. Bores in these formations were investigated with regard to depth to water bearing strata, yield obtained, reliability of yield and the quality of water. It was concluded that the yield from bores in basalt is mostly low and unreliable. Large quantities of good quality water can be obtained from the Quaternary alluvium along creeks or from the Jurassic sandstone