What are the facts about raising Warragamba Dam?

In any given year, what are the risks of your house burning down, you getting sick, or you crashing your car?

Low, I hope. These events have a low probability, but serious consequences. So we weigh the risk, and take out insurance.

So it is with our floodplain. There have been 124 floods in the Hawkesbury-Nepean since the 1790s. We had one this year (a baby — between 1:5 and 1:10 probability), and worse ones are a statistical inevitability.

The NSW Government 2017 report, Resilient Valley, Resilient Communities says that the damage of a bad flood could be between $5 billion and $7 billion dollars, considering that 134,000 people live and trade on the floodplain.

In a bad flood, 90,000 of those people would need to be evacuated. 12,000 homes would be inundated.

The report also says that this risk could be reduced by 75% if Warragamba Dam is raised by 15 meters, saving lives and slashing $5 billion from the damage bill. A wise investment, I think.

The cost would be that, in those rare rainfall events, a fringe of land around the current high waterline of Lake Burragorang would be subjected to temporary inundation, amounting to 0.04-0.05% of the Greater Blue Mountains World Heritage Area. Crucially, preliminary modelling suggests the most sensitive areas of the catchment, like the Kowmung River and its tributaries, would not be affected at all.

There is a lot of misinformation put about concerning the Warragamba Dam raising project. That it’s a stalking horse for development on the floodplain. That it will ruin a world heritage site. That it’s about increasing Sydney’s water supply.

These claims are not true — even though these issues are important. The project is about protecting life and property. I observe that most people who are opposed to the project don’t live on the floodplain. They live elsewhere, high and dry. They endure no risk to themselves, their families, or property. They are entitled to their views, but have no stake in the outcome.

The attached video is an interview I did recently when I was approached by someone doing some academic research from my alma mater, the University of Sydney. I summarise many of the points I frequently make about the project, and Hawkesbury Council’s attitude towards it.

I’ve written about this subject many times before:

Interviewed on ABC Sydney Radio about Warragamba Dam

Overnight, former Labor politician Bob Debus addressed a gathering of UNESCO in Baku, Azerbaijan, to seek their support in opposing the raising of Warragamba Dam.

This morning, ABC Sydney Radio asked to interview me to provide a response.

Here’s the audio. I repeat the argument I’ve made many, many, many, many, many times before.

Hawkesbury Council fails a test of leadership on flood safety

I am disappointed that Council last night reversed the position it has held for decades, and declined to reaffirm its support for raising Warragamba Dam to provide flood mitigation to our valley, through the Notice of Motion I brought to the chamber.

As I said last night, this issue is too important for it not to have bi-partisan support.

The Mayor of the Hawkesbury, Councillor Mary Lyons-Buckett voted against the motion.

In my opinion, the Mayor’s position as the chair of Council’s Flood Risk Advisory Committee is now untenable. In September last year, Council ratified new terms of reference and objectives of that committee, which specifically includes advocating for the flood mitigation strategies contained in the Hawkesbury Nepean Floodplain Review Taskforce report, Resilient Valley, Resilient Communities, ‘in partnership with relevant state agencies and stakeholders.’

That report’s signature capital flood mitigation initiative is raising Warragamba dam.

If the Mayor is unable to support the Committee’s objectives and show the leadership her predecessors offered on flood mitigation, then she cannot be its chair and she should resign from that committee.

Joint Media release - Flood Mitigation

Hawkesbury Council should support the raising of Warragamba Dam

Warragamba Dam in 1960

Warragamba Dam in 1960

Update: The result of the motion I put to Council is recounted here.

Only last year, we commemorated the 150th anniversary of the worst flood since European settlement in the Hawkesbury district. We were reminded that, back in June 1867, an inland sea of swirling detritus 30km wide stretched from Riverstone to the foot of the Blue Mountains —  the result of only four days of rain. The survivors in Windsor inhabited a shrinking island, huddled in St Matthews Church. Wearily, they grieved over the news of the drowning of 12 members from the one family, the Eathers, barely a mile away at Cornwallis. Past the mouth of the river, the beaches from Barrenjoey to Long Reef were black with uprooted trees and bloated livestock. Of course, many of the dead were never found.

Many people are unaware that the construction of Warragamba Dam in 1960 confers little in the way of flood protection to the communities downstream. The whole capacity of the dam is for drinking water storage. In the event of a rain event, there is no “buffer” to absorb flood waters in the dam and moderate its release, reducing the frequency and severity of flooding on the floodplain.

Recognising this, there have been thwarted plans to augment Warragamba since the 1980s by raising the dam wall, and we should welcome the State Government’s June 2016 commitment to a $700 million program to finally raise the dam by another 14 meters, giving it that crucial buffer. It is clear that the Hawkesbury Council, representing the community most at risk from flooding, should support this new initiative. I have been advocating and writing about this for many years.

To date, Council has not availed itself of the opportunity to express this support, and it would be timely for it to do so in the face of well intended but misguided opposition from environmentalists.

Thus, I and my fellow Liberal Councillors are bringing a Notice of Motion before the chamber next Tuesday to invite my colleagues to show their support for this measure which will protect your life and property against the rare but potentially catastrophic effects of a bad flood. I will have more to say on this soon.

ORD_APR1_2018_BP_NOM(WarragambaDam)

Commemorating the 1867 Hawkesbury Flood

To help commemorate the upcoming 150th anniversary of the tragic, yet fascinating events of the 1867 flood, I recently took The Hawkesbury Gazette journalist Justine Doherty on a brief tour of the flood exhibit at the Hawkesbury Museum.
I talk about flood history in the Hawkesbury, a subject dear to my heart as I am the direct descendant of a third-fleet victim of the Windsor flood of 1809 (William Kentwell), and I remind everyone that they should come to Thompson Square on the evening of Friday 23rd June to join the official commemorations.
The Gazette’s story is which I appear is here.