The Grose Valley is a rugged valley in the Blue Mountains, New South Wales, Australia. It has been formed by the Grose River, the headwaters of which are in the Mount Victoria area. The valley is located between the Great Western Highway and Bells Line of Road, the two major routes across the Blue Mountains. The majority of the valley falls within the Blue Mountains National Park.
Grose wilderness features
The Grose Wilderness contains some of the most dramatic gorge and canyon landscapes of the entire Sydney basin sandstone region. The Grose also constitutes one of the most accessible wilderness areas for bushwalking or public observation from its escarpment margins.
Geology
The geology of the area consists of Triassic sandstones and underlying Permian sedimentary rocks. A number of basalt-capped peaks dominate the area, notably Mount Banks and Mount Hay. The Grose River and its tributaries have eroded an extensive labyrinth of gorges and canyons through the Hawkesbury (upper) and Narrabeen (lower) group sandstones, exposing cliffs of commonly over and up to in height (Banks Wall). The Burramoko Head sandstone in the upper and middle Grose gorges possesses weathering tendencies of breakage along vertical joints and has consequently yielded some of the sheerest cliff faces in the Blue Mountains. The wilderness contains 80% of the Grose River catchment. The river flows to the Nepean-Hawkesbury through an undisturbed environment for all but its final . Consequently, the Grose has substantial wild river values, as do its major tributaries such as Wentworth Creek and Carmarthen Brook.
Flora
The bulk of the vegetation in the wilderness is dry open forest and woodland, dominated by Eucalyptus sieberi and E. piperita above altitude with Eucalyptus oblonga, E. globoidea, E. agglomerata and Angophora costata becoming dominant at lower altitudes. Plateau areas have thinner or waterlogged soils and generally support heath or low open woodland communities. Within the sheltered and well watered canyon environments closed forests commonly occur, with typical species being coachwood, sassafras and possumwood. On the isolated basalt caps the fertile soils support taller eucalypt forests of E. viminalis, E. blaxlandii and E. fastigata. A small area of alluvial sediments deposited in the upper Grose Valley during the Quaternary supports a tall moist open forest dominated by E. deanei, E. oreades, E. notabilis and E. cypelocarpa. The Blue Gum Forest is included in this forest type.
Fauna
The river is known habitat for platypus and certain hanging swamps provide habitat for the endangered and endemic Blue Mountains water skink (Eulamprus leuraensis). The rocky sandstone complexes of the plateau provide habitat for some specialised and rare native animal species (e.g. the broad-headed snake, Hoplocephalus bungaroides). Woodland communities are habitat for mammals such as the red-necked swamp wallaby, brush-tailed rock wallaby and eastern pygmy possum.
History
Aboriginal history
Aboriginal artefacts have been found close to the Blue Gum Forest.
European history
The Grose River has cut a deep gorge through the area as it makes its way east towards the Hawkesbury River. Sheer sandstone cliffs standing hundreds of metres above the river make for spectacular scenery and can be viewed extensively from the Blackheath area, where there are a number of accessible lookouts, the best known being Govetts Leap. The valley can also be viewed from lookouts near Bells Line of Road and points outside Mount Victoria. It is named after Francis Grose.
Charles Darwin described the Grose Valley as "stupendous… magnificent" when he visited in 1836. In 1859 some of the first photographs in Australia were taken in the valley. At various times there were proposals for rail lines and dams but these have not proceeded. In 1931, the valley was the subject of one of Australia's first forest conservation battles.
Within the valley, the Blue Gum Forest is one place that stands out from the rest of the valley. It consists predominantly of towering Blue Gum trees (Eucalyptus deanei, also known as Deane's Gums, or Broad-leafed gums), with a thin understorey because the tall trees inhibit the growth of ground cover by blocking most of the sunlight. Protected by the Blue Mountains National Park, the forest can be accessed only on foot, with several trails from different parts of the Grose Valley and adjacent canyons meeting in the forest.