In April 1966, construction commenced on the Berowra to Hawkesbury River section. This section traverses steep and rocky terrain and has climbing lanes for 3km immediately south of the Hawkesbury River. The interchange with the Pacific Hwy at Berowra included toll booths and Heavy Vehicle Checking Stations that were placed to catch both Pacific Hwy and freeway traffic. The toll booths also were the first to use automatic toll collection facilities in Australia.
At its northern end, temporary ramps connected the freeway to the Pacific Hwy and Peats Ferry Bridge, traces of which can be found today. These ramps were removed when the freeway bridge over the Hawkesbury River opened in 1973.
In conjunction with this project was the reconstruction of the Pacific Hwy to 6 lanes through Berowra and 4-lanes south to Mt Colah to form an improved access route to the north. This was an interim measure until the Berowra-Wahroonga section could be constructed.
The Berowra to Hawkesbury River section opened to traffic in December 1968.
While the F3 was steadily making its way north, work was underway to extend the freeway south to meet the Pacific Hwy and Pennant Hills Rd at Wahroonga. Commenced in February 1984, this section traversed the escarpment generally following the railway line and skirting the western boundary of Ku-ring-gai Chase NP. This section provided considerable environmental problems to engineers, with the original alignment having to be shifted away from a rare Boronia tree growing in a nature reserve. Wombat underpasses were also provided to allow them access to water. The southern 5km of this section was constructed with 6 lanes to assist with the merging of traffic and the climb onto the ridge at Ku-ring-gai Chase Rd.
Info from the rather fascinating ozroads website.
This large paperback sized cache has been placed on sliver of land that managed to avoid the bulldozers and dynamite that carved the M1 through lovely Hawkesbury sandstone. Soaring at 200 metres above sea level, it is one of the highest natural points of Sydney. Look down and out and marvel at the skill of the engineers and roadbuilders at what they achieved.
Children should not attempt this cache. The drop offs are decent and it's a bit of a scramble to get here.
I have listed a parking point (accessible from motorway southbound only, otherwise turn around at the Hawkesbury River bridge interchange and come back). There is also a reserve on the Old Pacific Hwy at the old toll gates, you can park your car and walk down the off ramp.
Log, pencil and room for treasure.
Well done bella at waggy for the FTF. Great photo too (appreciated by Mrs Importunity who forgot to take a photo when we hid it)