Parliamentary Committees

Public Works Committee: Port Road Drainage Project

Debate resumed.

Mr MURRAY (Davenport) (11:47): I may take issue with the use of the word 'sprung', but I will continue nonetheless. I, too, rise to talk very briefly about the Port Road drainage project. As a member of the Public Works Committee, I wish to commend the project to the house and also provide some further detail on the project and its impact on not only the immediate area but also ecologically. I also want to talk a little more fulsomely than my colleague the member for Kavel has insofar as the specific benefits to cost ratio that are anticipated as a result of the project.

The project itself covers a total area of the Port Road catchment, about 657 hectares, predominantly in the City of Charles Sturt. The project dates back to 2002 as a by-product of the Port Road Rejuvenation Stormwater Management Plan, which was in turn gazetted in 2007 and which recommended expenditure of about $60 million staged over a number of years. Stage 1 was completed in 2014 and stage 2 in 2016. The proposal put before the Public Works Committee, which is the subject of this discussion, the stage 3 works, are expected to finalise the project in its totality.

The specific aims of the project are, as the term implies, flood management, stormwater quality, stormwater re-use and environment protection, which I will detail further. The proposed works detail roughly 2.3 kilometres of underground twin and single-cell trunk drains between Park Street South in Woodville and Minnie Street in West Croydon, as well as the installation of approximately 4,000 square metres of underground detention storage or, in layman's terms, a very large tank. The proposed works are expected to contribute the following outcomes:

the elimination of frequent 'nuisance' flooding along Port Road;

an acceptable level of flood protection for the community thereof and, in particular, improved road access and egress for critical infrastructure in the event of a one in 100-year flood, not the least of which being The Queen Elizabeth Hospital on Woodville Road and the SA Power Networks substation on Port Road itself;

a reduction in the volume of stormwater discharged into Gulf St Vincent and an improvement in the quality of that stormwater, achieved by virtue of linking the Port Road stormwater discharges to the stage 1 works, which comprises wetlands and settling basins; and

an improvement in the amenity of the Port Road and surrounding areas streetscape.

Further to the primary goal of the level of flood protection being afforded, the total expenditure that is the subject of this proposal is $27.6 million, with an expected completion date of November this year. Further to the desired outcomes, the Stormwater Management Authority does advise that there are no natural watercourses or water bodies of significance.

However, the catchment at the moment does discharge and will discharge through the old Port Road wetlands and, as a result, provide an overall improvement of the quality of the stormwater that is being discharged. So the project is essentially about flood control and also diverting the stormwater in question so that we have a better ecological outcome and not simply flood control and prevention.

One of the primary measurements of any project coming before the committee is some indication of the intended or the expected cost to benefit ratio. I can advise the house that in this particular case there is an expected overall benefit to cost ratio of some 2:1; that is, for the expenditure of the money that is the subject of the approval put before the Public Works Committee it is anticipated that in excess of double the amount will be derived by way of benefit to the broader community. In particular, that will involve the avoidance of actual and potential damages of somewhere in the vicinity of $115 million. The evidence before the committee indicates that that is a conservative estimate.

It is on that basis and with consideration of the other evidence and testimony given before the committee, which the committee received—as the member for Kavel has indicated, written and oral evidence—and the undertakings provided to us insofar as the appropriate acquittals having been received, that the committee recommends the approval of the proposed public works. In so doing, I endorse that proposal.

Mr PATTERSON (Morphett) (11:53): I also rise to speak, in the time remaining, on the 24^th report of the Public Works Committee, entitled Port Road Drainage Project: Stage 3 Works. The report itself examines the history of the proposal, which has been outlined previously by both the member for Kavel, who is our Chair, and the member for Davenport, and looks at the efficacy of the application of South Australian taxpayer funds to this Port Road drainage project. Port Road itself is an arterial road and the catchment around it from rain extends both along the north and south sides of Port Road, going from the western Parklands in Adelaide.

Only a week or two ago, we saw the chimney unveiling at the West End Brewery when the Glenelg Football Club proudly put their colours on top of the chimney for the first time in 33 years, which was a great day for them. The catchment from there extends all the way down to West Lakes, which represents a total area of 657 hectares and, in terms of covering the councils in that catchment area, it is predominantly in the City of Charles Sturt, making up 618 hectares but also a small portion of the City of Port Adelaide Enfield, which is 39 hectares.

For most of the length of this Port Road project, there is an underground drainage system through pipes that runs along Port Road. Unfortunately, because it is quite dated, its capacity is less than a one-year average event in terms of rain. What that means is that, with the rain that comes into the drainage system, it exceeds the capacity. On average, once a year there is nuisance flooding and inconvenience to residents and businesses, and 'nuisance flooding' is a bit of an understatement.

The committee was presented with quite a few images of the flooding. Because of the camber of the road, a lot of the drainage goes towards the buildings, so on the building side of the road you can see it comes up quite high. We were shown quite a few pictures of floods and how high it went up—up to the windows of these businesses and houses—so I think a nuisance is an understatement and a reason for the upgrade.

The upgrade began in 2002. The City of Charles Sturt began developing their stormwater management plan for Port Road and it has been worked through ever since. Stage 1 works were completed in 2014, which included the Old Port Road wetlands, and then stage 2 works were completed between 2016 and 2018, which included upgrades to the drainage system between Old Port Road and Park Street South in Woodville. So this stage 3 takes over from that and finishes off the works. It has been run past a number of consultation processes and touched base with a number of departments.

Certainly, the Stormwater Management Authority was part of that. Residents and businesses were also consulted along with the Adelaide and Mount Lofty Ranges NRM and the Department for Environment and Water. The current proposal includes that the works will be a continuation of the previous works. It looks to install approximately 2.3 kilometres of underground twin and single-cell trunk drains between Park Street South in Woodville up to Minnie Street in West Croydon.

Also, the installation of approximately 4,000 cubic metres of underground detention storage. Again, we were shown pictures of that. That is quite a substantial reservoir of water which will help in terms of any surges and flash floods in being able to minimise the effects of those by storing that water in these underground detention storage areas. The proposal also proposes some service relocation required to accommodate the trunk drain and also any associated streetscaping.

In terms of what the benefits of this proposed work will be, it will certainly eliminate that frequent nuisance flooding along Port Road. It also looks to provide an acceptable level of flood protection for the community along Port Road and to provide that improved road access. Again, those photos showed that when it was flooded, there was only one lane out of the three lanes that could be used by traffic. Importantly, it looks to protect critical infrastructure to have a level of a one in 100-year events. It will provide flood protection to The Queen Elizabeth Hospital on Woodville Road and the SA Power Networks substation on Port Road, Woodville.

To conclude my remarks, I note that we examined written and oral evidence to the Public Works Committee for these Port Road drainage stage 3 works and, based upon that evidence, we report to parliament that the committee recommends the proposed public work.

Mr CREGAN (Kavel) (11:59): I thank members for their contributions and their ongoing diligence and commitment to the work of the committee.

Motion carried.