Thank you for your email since our discussions at the WRBG working bee this morning at the Amadeus Place gully off Callabonna Street.
I have done just a quick analysis this evening of the basis for a walking path design from a junction with the Coucal Trail, Point (A), to the Fig Tree near Tennent St, Point (B). This analysis and attachments are based upon on the 1994 aerial photography and terrain data obtained from DNR&M's new MapView product (recently purchased as part of BCC Environment Grant funded biodiversity monitoring project).
The attachments are:
.. Gidgi-Tenn00.jpg Aerial photo image, showing a straight line from Point (A) to Point (B)
.. Gidgi-Tennent.xls Excel spreadsheet showing distance and elevation data for the above straight line, which has a length of less than 400m. The chart in this spreadsheet is not for the alignment of a walking path. The walking path would deviate from this straight line longitudinal section to follow closer to the contours.
.. Gidgi-Tenn02.jpg Aerial photo image, showing a likely route for a walking path from (A) to (B) which would have a length of about 450m. This route aligns better with the contours for a graded path, though the last stretch on the approach to the Fig Tree will require a zig-zag path and/or steps to reach the elevation of the park at Tennent St.
An outline of the proposal is as follows:
To provide a walking trail along the Pullen Reach bushland reserve from a junction with the existing Coucal Trail, northwards across a deep gully opposite Amadeus Place, and skirting around the contours to connect to the parkland at Tennent St, nrth-west of the Fig Tree.
When the subdivision of Callabonna St from Amadeus Place to Tennent St was planned and approved, no provision was made for a pedestrian and cycle connection between Callabonna St and Tennent St at the boundary of the new residential area and the Pullen Reach riverfront bushland reserve. A broad, deep gully immediately south of the Fig Tree was filled for the residential development which was completed in late 1998. Because no graded pedestrian/cycle was provided, walkers soon created a 'desire line' path across the two back-to-back allotments which connected Callabonna St and Tennent St.
SORB representations at the time were ignored and this faulty subdivision planning was highlighted in an article SORB's March 1999 Newsletter, viz.: http://www.sorb.org.au/resources/nl11/tennent.htm
This legacy issue has now come to a head because one of these remaining two (still vacant) allotments is about to be built upon. This will prevent the many people who walk along the bushland/residential boundary from Callabonna St to Tennent St from continuing to walk thi route parallel to the river.
The topography of the broad deep gully south of the Fig Tree, and the lack of provision for a pathway corridor as part of the subdivision, make it impossible to provide a direct pathway link between Callabonna St and Tennent St. The roadway for Callabonna St was built on a fill batter which exacerbated the topographic challenges for such a link, increasing the elevation above the natural ground.
In order to provide for continuity of this pedestrian linkage, with a reasonable grade, the only solution is to construct a new path through the bushland reserve which follows the contours, below the Callabonna St fill batter, from near Amadeus Place.
Proposed New Walking Path
Sensible planning would suggest that a proposed walking path should connect from the existing Coucal Trail (see http://www.sorb.org.au/maps/Coucal%20Trail.PDF ) nears its northerly limit at Callabonna St near Nisbet St, with the above-noted alignment west of (and below in elevation to) the Callabonna St fill batter northwards from Amadeus Close.
The nominal alignment is shown in green in the attached image Gidgi-Tenn02.jpg.
This proposed path includes the following elements:
1. Walking Path from Coucal Trail, Point (A), to a deep gully opposite Amadeus Place - length approx. 150m
2. Bridge structure across this gully - length say 15m, height approx 4m
3. Walking Path from this gully, northwards, skirting along the contours to the lower reaches of the gully near the Fig Tree, then climbing to a point north-west of the Fig Tree - length approx. 300m.
4. Option of a connecting path along the north side of gully at Amadeus Place, from Callabonna St to the above path at the north side of the bridge (2. above) - length approx 50m
The total length of walking path is therefore approx 500m, plus one major structure opposite Amadeus Place. The climbing grade on the approach to the Fig Tree end of the path needs to be carefully addressed.
The standard of construction and surfacing of the Walking Path should be similar that for the Coucal Trail, with a gravelled surface and edge block treatment, as built in 1999 under a Green Corps project.
In the past, an informal path had existed for this full length. The alignment had been constructed as part of BCC-supervised labour program circa 1994/95 and was kept open by WRBG volunteers by occasional brush-cutting of Guinea Grass weed infestation. Since banning of blade brushcutters for WH&S reasons, this work was not continued by WRBG volunteers and the path has become overgrown and disused. Guinea Grass remains a challenge for most of the length of the proposed path.
The alignment of the original path, however, was not carefully planned and has also suffered land slips. Better planning and proper design of a new route is essential.
Revegetation of this northern half of the Pullen Reach site remains a major challenge, and will not occur naturally nor through volunteer bushcare effort. A major injection of resources is required to reverse the vegetation damage and ensuing weed infestation caused by Australand's reckless clearing of the site, several weeks before the original VPO's came into force in 1991. (That action lead to the formation of SORB and the subsequent reservation of the land for bushland park.)
The above proposal provides the basis for holistic, master-planned approach for a walking path facility and revegetation in this northern part of the Pullen Reach Bushland reserve.
We have not been able to cost this proposal, but it would be in excess of $50,000. (Figures for ecological restoration of vegetation alone, as quoted at a recent THECA weed management workshop, are $30,000 per hectare as typical estimate.)
However, if an overall master plan approach is taken, stage construction would be possible. For example, Items 3 and 4 (path from Amadeus Place to Tennent Street Fig Tree) could be undertaken first. This first stage would overcome the legacy planning issue of lack of pedestrian continuity between Callabonna St and Tennent St.