The case study is made possible by access to Council files and interviews with Council Officers permitted by Hobart City Council. The developer, Jim Grant, also reviewed the information presented. This assistance is gratefully acknowledged.

The Tolmans Hill subdivision is a major housing development, effectively the creation of a new suburb in a visually prominent bushland setting in the foothills of Mt Wellington located close to Hobart. The visual prominence of the subdivision provides residents with spectacular views of Hobart and environs. Whilst the elevation and gradients require that Tolmans Hill will be a predominantly car based suburb, the location relatively close to Hobart also provides for good access by its residents to existing services and, thereby, a relatively more efficient use of these services.

The subdivision proposal approved by Council sought to maintain some of the bushland and landscape values of the area. The extent that these intentions have not been fully realised can be attributed to the planning system and the challenges of sometimes conflicting values and objectives (e.g. management of understorey for bushfire hazard reduction versus bushland retention). This case study identifies some of the lessons that might be applied to other developments in the future, including the need for a strategic and regional approach to new housing development. Such an approach would need to give consideration to all housing sub-markets, including the premium sub-market catered for in developments such as Tolmans Hill.

The community has a range of values about housing, bushland management and skyline protection. These values change at different rates for different community interests through time. Living 'on the high ground' is as much a community value as being able to 'view the high ground'. 'Balancing' these values is one of the challenges for urban design, liveability, skyline protection, fire hazard management, and bushland management in Hobart and many other parts of Tasmania (and many other cities around the world).

Tolmans Hill was used for grazing and had been so for many years. It had increased its tree cover since the 1967 fires, especially during the 1980s in the lead up to conversion to housing. Community attitudes up until the 1980s favoured land clearance and conversion to housing for the area as the agricultural, timber and catchment values were not considered high.

The development now occurring on Tolmans Hill is the outcome of decisions dating back to the 1980s. In 1985, the council noted that Tolmans Hill was not an ideal area for development (Hobart City Council 1985) and pointed to disadvantages including: steep slopes; costs of land development; difficulties in designing an overall street layout of acceptable standards; one access point only; and, a certain amount of physical isolation. Bushland and landscape values, however, were not viewed as an impediment to the development of the subdivision. The same report also referred to advantages including: close to CBD; extensive views; access via a major arterial road; attractive residential area; and, services can be supplied without undue physical difficulty. The report recommended that the area should be developed as a residential precinct with lot sizes minimum of 550 m².

In 1989, Hobart City Council considered a sketch proposal and resolved that the subdivision was a practical scheme. In 1991, Council approved a subdivision of 415 lots. By late 2001, some 80% of the development of the approved subdivision was still to occur, although many of the premium sites in the northern precinct have been developed.

The subdivision required significant upfront infrastructure expenditure by the developer. This large initial capital outlay has limited options to vary the development (e.g. to reduce the number of lots) in order to better respond to the objectives set out in the principles of the development (Gulson 1995), the statement of desired future character of the precinct and the changes in community values outlined above. Capacity to manage adaptively to respond to changes in community expectations, or actual performance of the subdivision in achieving objectives, is constrained by the overriding requirement for cost-recovery on the large initial capital outlay.

Condition

The development of land from bushland to suburb represents a significant change in environmental condition that can impact on remnant vegetation species and communities, water quality, and landscape values (social, cultural and visual). Impacts on resources and environmental systems, and potential disturbance to natural systems and natural hazards tend to increase as the land becomes steeper and higher. The principles of the Tolmans Hill subdivision and the Local Area Plans that guide its development sought to manage these impacts to preserve some of the bushland and landscape values. However, despite these principles, with 80% of the development still to occur there are significant challenges in preserving bushland and landscape values in the area.

A classification of landcover in 1999 shows that sufficient clearance had occurred to already place landcover at Tolmans Hill in an urban class (suggesting greater than 50% vegetation clearance). It illustrates a significant challenge for a bushland development at normal residential lot sizes to retain 50% or more of the vegetation for each lot (a principle of the development). The provision of infrastructure and roads and easements is itself responsible for a significant amount of vegetation loss.

At the time of the subdivision approval in 1991, a detailed flora and fauna survey had not been undertaken for the proposed subdivision. In 1995, responding to the imminent development of Stage 1, a botanical reconnaissance of a single day was undertaken as a preliminary assessment of the vegetation. The report noted that it was likely that vegetation communities were overlooked and that the species list was incomplete (North 1995).

The botanical report identified that the north-east ridge of the subdivision contained the high priority Eucalyptus viminalis grassy woodland community. A small area of Eucalyptus viminalis grassy woodland has since been lost through the stage 5 development of the subdivision. Other than this area, and while noting the concerns that vegetation communities had been overlooked, it is unlikely that the subdivision will impact on the highest priority vegetation communities. Nevertheless, there is a risk that threatened flora and fauna may be impacted by the subdivision, but no evidence is available through survey work.

In relation to landscape values, it was known at the time of its approval that the subdivision was prominent and of some landscape significance, although it was not considered of regional landscape significance. The Gulson report prepared in 1995 as a condition of the planning approval noted that: 'Tolmans Hill lacks topographic features of individual landscape significance'.

Greater consideration to the cumulative losses of bushland and landscape values on hill slopes across greater Hobart was needed and remains a priority. However, at the time the subdivision was approved in 1991, decisions to proceed with a subdivision, such as Tolmans Hill, were made largely on engineering and surveying grounds, and on the existing residential zoning.

In addition to the changes in legislation and greater involvement now by planners in subdivision assessment, consideration for resource management and the environment has improved. Methods for visualising and assessing landscape significance have also improved significantly in recent years. Using geographic information system tools, such as those developed by the Urban skylines and hillfaces Committee (DPIWE 2000), the degree of visual sensitivity can now be classified. These techniques overlay areas of high elevation, significant natural features and areas of high slope classification with areas of high and moderate hillface and skyline visibility. This is used to determine visual sensitivity as low (outside all of these areas), moderate (where only one value occurs), high (where two values overlap), or extreme (where more than two values coincide) (DPIWE 2000). Using these assessments, Tolmans Hill has a high visual sensitivity, particularly in those areas that have been developed initially as indicated by the overlay of cadastre and high visual sensitivity in the following map.