Hobsons Bay City Council 1 December 2015 Ordinary Council Meeting Agenda. Appendix 7. Service Report Infrastructure and City Services

Transcription

1 Hobsons Bay City Council 1 December 2015 Ordinary Council Meeting Agenda Appendix 7 Service Report Infrastructure and City Services

2 Service Report Infrastructure and City Services 23 October 26 November 2015 Flooding in Hobsons Bay Hobsons Bay City Council has a unique combination of extensive low lying areas, 24 kilometres of foreshore and five major waterways, which are downstream of urban growth areas. Flooding is of growing concern with storm events becoming more frequent and intense and sea levels rising. In the last 100 years there have been five 1 in 100 year flood events. These occurred in 1919, 1963, 1977, 1983, Flooding can lead to road closures and restricted access to properties and areas and in extreme cases can cause damage to council assets and private property, impact on human health and lead to loss of land (recession from erosion). Infrastructure and City Services plan for and respond to flooding events in the following ways: mapping and flood modelling to understand the capacity and impacts of flood events on our drainage network. infrastructure improvements to protect foreshore areas and open space and upgrade or install drainage infrastructure. planning and design of facilities and infrastructure to mitigate, withstand or avoid flooding maintenance activities to ensure drains and gross pollutant traps are kept free of debris and broken pipes are repaired emergency response actions. Council s role in these events is to support the SES e.g.: with traffic management and clean up of debris in flood affected areas. In extreme flood events, for example where large areas are inundated and communities are affected Council would enact its emergency management plan which would involve a recovery response. Above: 1 in 100 years flooding of Kororoit Creek and surrounds in the mid 1980s

3 Above: Flooding of an Altona street due to drainage capacity being reached Above: Flooding of the Esplanade, Altona after a king-tide Above: In 2014 storm surges caused undercutting and collapse of large sections of the Coastal Trail.

4 Above: 2014 storm surge breaching the seawall at Altona beach.

5 Flood Mapping Hobsons Bay, Melbourne Water and the Department of Environment, Land, Water & Planning (DELWP) work in partnership to capture data which informs flood mapping and projected flooding models for the municipality. These flood maps draw on data including; rainfall patterns, recorded flood events, records of drainage and flood related complaints (CHARMs), GIS information and plans, planning scheme overlays, Council s Municipal Emergency Management Plan, capital works program and asset information. Once compiled, this mapping provides an overall view of flooding behaviour. It also identifies hot spots where flooding occurs regularly to help prioritise capital works, asset management planning and maintenance and traffic planning. Above: Flood map detailing flash flooding and waterway flooding projections for Hobsons Bay in a 1 in 100 year flood event. Drainage infrastructure Melbourne Water, Hobsons Bay City Council and VicRoads have combined responsibility for approximately 500 kilometres of underground drainage. Melbourne Water is responsible for the installation and maintenance of drainage systems for catchments with an area greater than 60 hectares. Council is responsible for drainage systems within catchments smaller than 60 hectares, which covers most residential areas. The division of these responsibilities is based on a memorandum of understanding between the two organisations. Some drainage, such as that associated with the Westgate and Princess freeways is the responsibility of VicRoads. Hobsons Bay City Council is progressively upgrading and replacing drainage infrastructure that has reached capacity (sometimes as a result of new development in the catchment) for example Ann Street, Williamstown.

6 Above: New underground, high capacity drain pipes being installed along Ann Street, Williamstown Council also replaces outdated drainage systems, such as the spoon drains in Williamstown, with underground drainage. Above: Victorian era open spoon drains being progressively replaced/serviced by new underground drainage systems

7 Above: The ford at Racecourse Road has been regularly damaged by fast moving flood water. Another cause of water related damage to roads is pondage. This occurs when water pools in one location and is unable to be syphoned away by kerb and channel into a drainage system. If ponding occurs over a long period of time, water can penetrate the bitumen surface and destabilise the gravel and sand sub-structure. Once this destabilisation occurs the action of vehicle tyres on the unstable surface causes it to break apart. Above: A road surface damaged by long-term water pondage

8 Above: Reflectors can be installed on flood-prone roads to indicate (through the water) the edges of the road at night. Above: Water depth markers help drivers asses the dangers associated with navigating a flooded road Flash Flooding and Stormwater Harvesting Heavy rainfall recently resulted in a flash flood at the Merton Street underpass, Altona Meadows. The underpass is located in a floodway well below the 1 in 10 year flood zone (meaning it is likely to flood more than once every ten years).

9 Underpass Above: Merton Street, Altona Meadows 1 in 100 Flood zone Since the construction of the Laverton Stormwater Harvesting Scheme just north of the underpass the frequency and severity of flooding through the underpass has decreased as the wetlands act as a retarding basin for floodwaters. After prolonged periods of rain the wetlands can fill to the point where they have no capacity to hold back floodwater. This was a likely contributor to recent inundation in the underpass. Other projects Road Condition Survey Preparation of tender documents for a Road Condition Survey is currently underway. The road condition audit is undertaken every four years, with the last audit taking place in April 2012, and forms part of Council s overall asset management strategy. The audit will provide Council with an assessment of the overall condition of our road assets including pavement, kerb, footpaths and traffic management facilities and assist in prioritising future capital works programs. The process will involve noting the age and condition of each road segment from new to ten years old. It will also help measure the extent of improvements made as a result of increased expenditure over the past two years.

10 Projects currently underway Phase Project Design/ J.K. Grant Reserve, Altona football and cricket pavilion consultation/master Brooklyn Dog Park planning/feasibility Second Avenue shops upgrade improvements, Altona North J.T. Gray pavilion Dennis Reserve Master Plan Cresser Reserve revetment works Digman Reserve Master Plan Epsom Street Master Plan Paisley Park Improvements Maddox Road pedestrian refuge Laverton Trail Maher Road to Merton Street Sportsground lighting audit/upgrade Laverton Swim Centre upgrade works Point Cook Road Catherine Road to Shane Avenue Tender awarded Thorpe St, Newport road rehabilitation from Woods Street to Rosshire Road Douglas Parade road rehabilitation and drainage works Under Construction Woods and Lohse Street road rehabilitation Bruce Comben Reserve pavilion extension Williamstown Town Hall refurbishment Ann Street drainage, Williamstown Newport Youth Library Seniors Recently Footpath Program for Wetlands Ward completed Various car park upgrades Railway Avenue shops, Laverton Upgrade Asphalt Program Newport Athletics pavilion Laverton Creek Trail - Watts Street section R.J. Cooper Reserve car park and landscaping Elizabeth Street nature strip improvements Loft Reserve Pavilion Events, participation and consultation activities Dennis Reserve Master plan Elizabeth Street, Newport One Way Trial Drop in Session The Dennis Reserve master plan community working group has been established, with 13 community members representing a wide range of interests. The first working group meeting was held on 26 October 2015, with each member having the opportunity to outline for the group their interest in the future uses of the reserve. An independent facilitator has been engaged to assist the community working group to develop master plan options for the reserve. On Wednesday 11 November Council hosted a drop in session at Outlets Community Centre to hear feedback on the recent one-way traffic trial on Elizabeth Street, Newport. A one-way scenario was trialled on Elizabeth Street adjacent to Newport Lakes Primary school to assess if traffic flow can be improved during school drop-off and pick-up times. The traffic congestion and cars moving in two directions during these times has reportedly caused bottlenecks, frustration and an unsafe environment for cars, cyclists and pedestrians. The drop in session was attended by approximately 10 community members who generously provided lots of informative feedback. This feedback will be collated and used to inform any decisions about the future of a one-way scenario and other issues or

11 opportunities to improve traffic conditions in the area. Above: Community members, Councillors and Council officers contemplating aerial maps of the areas surrounding the Elizabeth Street one-way trial.

12 Service Report Infrastructure and City Services 23 October 26 November 2015 Flooding in Hobsons Bay Hobsons Bay City Council is particularly susceptible to flooding compared to other metropolitan municipalities. This is due to unique combination of extensive low lying areas, 24 kilometres of foreshore and five major waterways, which are downstream of urban growth areas. Flooding in Hobsons Bay is caused by a range of factors, being: 1. Blockages in the drainage system, for example from tree roots in pipes, broken pipes, and debris on grates or in gross pollutant traps. 2. Runoff unable to enter the drainage network due to a lack of infrastructure or inadequate drainage conditions eg: depressions in the ground that trap water. 3. Intense rainfall events generating high volumes of runoff i.e. greater than the capacity of the existing drainage network. 4. High-tides and storm surges causing foreshore flooding. 5. Rising waterway levels and flash flooding during rainfall events as a result of being downstream of new developments (increasing areas of impervious surfaces that cause larger volumes of water to enter the creeks at a faster velocity). 6. Rising sea levels as a result of climate change. Flooding is of growing concern with storm events becoming more frequent and intense and sea levels rising. In the last 100 years there have been five 1 in 100 year flood events. These occurred in 1919, 1963, 1977, 1983, Flooding can lead to road closures and restricted access to properties and areas and in extreme cases can cause damage to council assets and private property, impact on human health and lead to loss of land (recession from erosion). Infrastructure and City Services plan for and respond to flooding events in the following ways: Mapping and flood modelling to understand the capacity and impacts of flood events on our drainage network. Infrastructure improvements to protect foreshore areas and open space and upgrade or install drainage infrastructure. Planning and design of facilities and infrastructure to mitigate, withstand or avoid flooding Maintenance activities to ensure drains and gross pollutant traps are kept free of debris and broken pipes are repaired Emergency response actions. Council s role in these events is to support the SES e.g.: with traffic management and clean up of debris in flood affected areas. In extreme flood events, for example where large areas are inundated and communities are affected Council would enact its emergency management plan which would involve a recovery response.

13 Above: 1 in 100 years flooding of Kororoit Creek and surrounds in the mid 1980s Above: Flooding of an Altona street due to drainage capacity being reached Above: Flooding of the Esplanade, Altona after a king-tide

14 Above: In 2014 storm surges caused undercutting and collapse of large sections of the Coastal Trail. Above: 2014 storm surge breaching the seawall at Altona beach.

15 Flood Mapping Hobsons Bay, Melbourne Water and the Department of Environment, Land, Water & Planning (DELWP) work in partnership to capture data which informs flood mapping and projected flooding models for the municipality. These flood maps draw on data including; rainfall patterns, recorded flood events, records of drainage and flood related complaints (CHARMs), GIS information and plans, planning scheme overlays, Council s Municipal Emergency Management Plan, capital works program and asset information. Once compiled, this mapping provides an overall view of flooding behaviour. It also identifies hot spots where flooding occurs regularly to help prioritise capital works, asset management planning and maintenance and traffic planning. Above: Flood map detailing flash flooding and waterway flooding projections for Hobsons Bay in a 1 in 100 year flood event. Drainage infrastructure Melbourne Water, Hobsons Bay City Council and VicRoads have combined responsibility for approximately 500 kilometres of underground drainage. Melbourne Water is responsible for the installation and maintenance of drainage systems for catchments with an area greater than 60 hectares. Council is responsible for drainage systems within catchments smaller than 60 hectares, which covers most residential areas. The division of these responsibilities is based on a memorandum of understanding between the two organisations. Some drainage, such as that associated with the Westgate and Princess freeways is the responsibility of VicRoads. Hobsons Bay City Council is progressively upgrading and replacing drainage infrastructure that has reached capacity (sometimes as a result of new development in the catchment) for example Ann Street, Williamstown.

16 Above: New underground, high capacity drain pipes being installed along Ann Street, Williamstown Council also replaces outdated drainage systems, such as the spoon drains in Williamstown, with underground drainage. Above: Victorian era open spoon drains being progressively replaced/serviced by new underground drainage systems Flood damage to roads Although rare, the most damage caused to roads is from fast moving flood waters. Fast moving water can remove the surface paving as well as undercut the road sub-structure, sometimes resulting in a section of road being removed entirely. An area particularly susceptible to this kind of damage is the Kororoit Creek Ford Crossing at Racecourse and Road, Altona.

17 Above: The ford at Racecourse Road is regularly damaged by fast moving flood water. Another cause of water related damage to roads is pondage. This occurs when water pools in one location and is unable to be syphoned away by kerb and channel into a drainage system. If ponding occurs over a long period of time, water can penetrate the bitumen surface and destabilise the gravel and sand sub-structure. Once this destabilisation occurs the action of vehicle tyres on the unstable surface causes it to break apart. Above: A road surface damaged by long-term water pondage Keeping Flooded Roads Safe Council regularly responds to traffic conditions at hotspots where road flooding is frequent. These hotspots include: Sargood Street near the Esplanade, Altona McBain Street near the Esplanade, Altona Douglas Parade, Spotswood at ScienceWorks Merton Street Underpass, Altona Meadows The Ford at Racecourse and Altona Roads, Altona Aviation Road, Laverton When road flooding occurs, Council uses a range of measures to improve road safety, including:

18 Closing the road entirely, Installing reflectors at the road edges to allow safe navigation of a flooded road at night, Installing water depth markers to inform road users of the actual flooding depth, Designing Traffic Management Plans, which include detours (where flooding takes a long time to subside). Above: Reflectors can be installed on flood-prone roads to indicate (through the water) the edges of the road at night. Above: Water depth markers help drivers asses the dangers associated with navigating a flooded road Flash Flooding and Stormwater Harvesting Heavy rainfall recently resulted in a flash flood at the Merton Street underpass, Altona Meadows. The underpass is located in a floodway well below the 1 in 10 year flood zone (meaning it is likely to flood more than once every ten years).

19 Underpass Above: Merton Street, Altona Meadows 1 in 100 Flood zone Since the construction of the Laverton Stormwater Harvesting Scheme just north of the underpass the frequency and severity of flooding through the underpass has decreased as the wetlands act as a retarding basin for floodwaters. After prolonged periods of rain the wetlands can fill to the point where they have no capacity to hold back floodwater. This was a likely contributor to recent inundation in the underpass. Other projects Road Condition Survey Preparation of tender documents for a Road Condition Survey are currently underway. The road condition audit is undertaken every four years, with the last audit taking place in April 2012, and forms part of Council s overall asset management strategy. The audit will provide Council with an assessment of the overall condition of our road assets including pavement, kerb, footpaths and traffic management facilities and assist in prioritising future capital works programs. The process will involve noting the age and condition of each road segment from new to ten years old. It will also help measure the extent of improvements made as a result of increased expenditure over the past two years. Beach Matting Installation To ensure Hobsons Bay s beaches are accessible to all community members, Council is trialling rubber matting across the sand at Williamstown and a beach wheelchair at Altona. Thirty metres of beach matting will be trialled at Williamstown beach on weekends and public holidays during the summer season. Beach matting creates a stable, hard and level surface for people with mobility issues to access the beach safely. City Services staff will be rolling out the matting in the mornings and the Williamstown Surf Lifesaving Club will be responsible for collecting the matting in the afternoon and

20 storing the matting at their premises. In Altona, Council will be trialling a Sandcruiser beach wheelchair that people with a disability can hire for free to get across the sand and to the water s edge. The pilot trial will run from 5 December 2015 to 27 March 2016 on weekends during lifesaving hours. Above: Sandcruiser beach wheelchair Above: Beach matting to be rolled out at Williamstown beach during summer

21 Projects currently underway Phase Project Design/ J.K. Grant Reserve, Altona football and cricket pavilion consultation/master Brooklyn Dog Park planning/feasibility Second Avenue shops upgrade improvements, Altona North J.T. Gray pavilion Dennis Reserve Master Plan Cresser Reserve revetment works Digman Reserve Master Plan Epsom Street Master Plan Paisley Park Improvements Maddox Road pedestrian refuge Laverton Trail Maher Road to Merton Street Sportsground lighting audit/upgrade Laverton Swim Centre upgrade works Point Cook Road Catherine Road to Shane Avenue Tender awarded Thorpe St, Newport road rehabilitation from Woods Street to Rosshire Road Douglas Parade road rehabilitation and drainage works Under Construction Woods and Lohse Street road rehabilitation Bruce Comben Reserve pavilion extension Williamstown Town Hall refurbishment Ann Street drainage, Williamstown Newport Youth Library Seniors Recently Footpath Program for Wetlands Ward completed Various car park upgrades Railway Avenue shops, Laverton Upgrade Asphalt Program Newport Athletics pavilion Laverton Creek Trail - Watts Street section R.J. Cooper Reserve car park and landscaping Elizabeth Street nature strip improvements Loft Reserve Pavilion Events, participation and consultation activities Dennis Reserve Master plan Elizabeth Street, Newport One Way Trial Drop in Session The Dennis Reserve master plan community working group has been established, with 13 community members representing a wide range of interests. The first working group meeting was held on 26 October 2015 and went very well, with each member having the opportunity to outline for the group their interest in the future uses of the reserve. An independent facilitator has been engaged to assist the community working group to develop master plan options for the reserve. On Wednesday 11 November Council hosted a drop in session at Outlets Community Centre to hear feedback on the recent one-way traffic trial on Elizabeth Street, Newport. A one-way scenario was trialled on Elizabeth Street adjacent to Newport Lakes Primary school to assess if traffic flow can be improved during school drop-off and pick-up times. The traffic congestion and cars moving in two directions during these times has reportedly caused bottlenecks, frustration and an unsafe environment for cars, cyclists and pedestrians. The drop in session was attended by approximately 10 community members who generously provided lots of informative feedback. This feedback will be collated and used to inform any decisions about the future of a one-way scenario and other issues or

22 opportunities to improve traffic conditions in the area. Above: Community members, Councillors and Council officers contemplating aerial maps of the areas surrounding the Elizabeth Street one-way trial.