Ordinary Meeting of Council 23 May 2007 4.4 PROPOSED BRIDGE ACROSS SWAN RIVER (REID HIGHWAY EXTENSION) - WEST SWAN ROAD TO GREAT NORTHERN HIGHWAY (Swan Valley) (Development Services) (DA289-07) KEY ISSUES • This proposal has been referred to Council for its advice and recommendations. The Swan River Trust is the decision making authority. • Main Roads WA has undertaken extensive consultation with local residents, other government agencies and the local Aboriginal people. • Issues of concern (such as environmentally sensitive areas) have been identified and satisfactorily addressed. • Whilst the existing bridge is listed on Council’s Municipal Inventory of Heritage Places, the Heritage Council advise that it is not likely to meet the threshold for entry on the State Register of Heritage Places. Recommended that the Swan River Trust be advised that Council has no objections subject to a condition requiring Main Roads WA to complete an archival record of the bridge prior to its demolition. AUTHORITY/DISCRETION This proposal has been referred to Council for its advice and recommendations. The Swan River Trust is the decision making authority. BACKGROUND Applicant: Main Roads WA Owner: Commissioner of Main Roads WA Zoning: TPS - Primary Regional Roads, Waterways MRS - Primary Regional Roads Strategy/Policy: Nil Development Scheme: Nil Existing Land Use: Bridge and vacant land (road reserve) Lot Size: 6645m2 Area: 6645m2 Use Class: N/A Page 1 Ordinary Meeting of Council 23 May 2007 DETAILS OF THE PROPOSAL The finished detail and design of the proposed new bridge and construction of Reid Highway will be completed via a Design and Construct Contract. Nevertheless Main Roads WA’s preferred design is as follows: • A 23m wide and 228m long bridge with uniform spans, constructed using concrete. • Allowing for 4 traffic lanes, on road cycle lanes, a separate pedestrian/cycle path and appropriate barriers and railings. • To cater for the ultimate requirements for a 6 lane freeway and provision for light rail, a duplication of the bridge immediately south will be required in the future. • A maximum of one pier will be permitted in the Swan River. • Service roads are proposed either side of the Reid Highway to ensure amenity is provided to local residents. These will be maintained by the City of Swan upon completion of the works. DESCRIPTION OF SITE The existing bridge is a timber bridge with an overall length of 134 metres. The associated land is a road reserve and is therefore vacant, undeveloped land. SITE HISTORY/PREVIOUS APPROVALS Known as the Whiteman Bridge (Middle Swan Bridge No.920), the bridge was constructed in the 1950’s. No approvals for the subject land are recorded. The subject land and the Swan River have significant heritage value for the local Aboriginal people, discussed further in the applicant's submission. OTHER RELEVANT PREVIOUS DECISIONS OF COUNCIL Whilst this is the only occasion this proposal has been formally referred to Council, it has previously been briefed by Main Roads WA. Council advised Main Roads WA that it had no objections to the proposal. APPLICANT'S SUBMISSION As stated above the Swan River Trust has referred this proposal to Council for its comments and recommendations. Environmental Considerations Page 2 Ordinary Meeting of Council 23 May 2007 The proposal to construct Reid Highway from Beechboro Road to Great Northern Highway was conditionally approved by the Minister for the Environment in 1995. Waterways Investigations One Ministerial condition requires that Main Roads WA design the bridge at the Swan River such that its flow is not impeded by accommodating a 100 year flood event and complying with the backwater constraints of the Water Corporation. Hydraulic analysis of the existing and proposed bridge crossings was conducted using software programs in consultation with the Department of Water. The bridge structure proposed was determined to be the most appropriate given the local geotechnical conditions, impact on upstream flooding and cost effectiveness. Bush Forever The proposed location for the bridge is in Bush Forever Site 302 – Swan River and Jane Brook Ashfield to Upper Swan and is part of a regionally significant contiguous bushland/wetland linkage. The Bush Forever office of the DPI has advised Main Roads WA that it will provide its comments and recommendations once the proposal is formally referred to its office from the Swan River Trust. Impact to Environmentally Sensitive Areas The Swan River is a conservation category wetland and is protected under the Revised Draft Environmental Protection (Swan Coastal Plain Wetlands) Policy 2004. In 2005 a biological survey was undertaken for the subject land. Based on the Bush Forever vegetation condition rating scale, ratings of degraded to completely degraded were given to the riverine vegetation. There are no threatened population flora within the project. Acid Sulphate Soils and Groundwater Investigations A preliminary Acid Sulphate Soils (ASS) and groundwater investigation has been carried out. Although the results confirmed a low ASS risk throughout most of the subject area, an ASS management plan and dewatering management plan will be prepared in accordance with the Department of Environment and Conservations guidelines once the Design and Construct Contract has been awarded. Consultation with the Local Aboriginal People In 1991 Main Roads WA gained Ministerial consent under Section 18 of the WA Aboriginal Heritage Act 1972 to enter the subject land for the purpose of site investigation and road and bridge construction. In 2005 a preliminary desktop Aboriginal heritage review of archaeological and ethnographic sites of significance on the subject land was undertaken. In 2006 a detailed archaeological field survey and ethnographic consultation with the local Aboriginal people was completed. Although the site has historical significance for the Aboriginal people, they have given their conditional consent for the proposal to proceed, in view of the fact that the proposal will improve safety on a dangerous stretch of road and bridge. Page 3 Ordinary Meeting of Council 23 May 2007 Consultation with the Heritage Council Whiteman Bridge is owned by the City of Swan and is listed on its Municipal Inventory. Initial consultation with the Heritage Council of WA revealed that it was unlikely that the bridge would meet the threshold for entry on the State Register of Heritage Places. Council has previously advised Main Roads WA that it does not object to the removal of the bridge. Erosion and Sediment Control A detailed scour analysis has not been carried out, however based on the low velocities at the crossing, the scour potential of the site is considered to be minimal. Management of Stormwater Areas adjacent to the Swan River and Jane Brook (including the new bridge) will be kerbed and runoff piped to drainage basins to prevent direct runoff to these sensitive wetland areas. Removal of Existing Bridge Dismantling of the bridge will be in accordance with Main Roads WA Specification 803Dismantling and Demolition and in accordance with its Specification 204 Environment. A more detailed dismantling procedure will be prepared as part of the Design and Construct contract. PUBLIC CONSULTATION The proposal has been the subject of a Public Environmental Review in 1993. As mentioned above consultation has also occurred with the local residents and Aboriginal people by Main Roads WA. CONSULTATION WITH OTHER AGENCIES AND/OR CONSULTANTS As summarised above in the applicant's submission, extensive consultation has occurred with other relevant government agencies. REPORT Main Roads WA has carried out extensive investigation into the many issues involved in the construction of this major development since 1992. It is considered that all the areas of concern to Council such as environmental and Aboriginal heritage issues have been satisfactorily addressed. Demolition of Existing Bridge Whiteman Bridge is entered onto Council Municipal Inventory of Heritage Places (MI), however it has not been given a management category. Page 4 Ordinary Meeting of Council 23 May 2007 The Statement of Significance from the MI is as follows: Historical Value: The earliest bridge on this site was built in 1897 to connect the eastern side of the Swan Valley with the west. Previous to this, between Guildford and the Upper Swan Bridge, there had only been a private bridge at ‘Oakover Farm’, built in the 1840’s, to connect the two sides of the Valley. The Oakover bridge was destroyed in the flood of 1862. The existing bridge is a reminder of this earlier history. Technological value: The bridge illustrates the methods and materials used in timber bridge-building. Although Whiteman Bridge is listed on Council’s MI, Council has previously advised it has no objections to the removal of the bridge. Furthermore the Heritage Council of WA undertook a preliminary review of the bridge’s heritage value. It advised that whilst it may have some cultural heritage significance, it was unlikely to meet the threshold for entry on the State Register of Heritage places. Whilst the bridge has some heritage significance, the advantages of improving what is currently a dangerous stretch of road and bridge, is a significant consideration that, on balance, outweighs the loss of the existing bridge. OPTIONS AND IMPLICATIONS As stated, Council is a referral body in this process, the Swan River Trust is the decision-making authority. Council has previously indicated its support of the proposal. If Council did not support the proposal, the Swan River Trust has the authority to proceed regardless. CONCLUSION The proposal represents a continuation of the Reid Highway and a substantial improvement to what is currently a dangerous stretch of road and bridge for drivers, cyclists and pedestrians. It is recommended that Council advise the Swan River trust that it has no objections subject to Main Roads WA engaging a suitably qualified person to undertake an archival record of the bridge to Heritage Council standards, prior to its demolition.