January 20, 2021

The news service people turn to for quality information and opinion.

Daintree River Crossing Issue 2 / Bridge Options Costs and Other Considerations

12 min read
This article investigates the costings and issues associated with the four bridge options presented in Douglas Shire Council's Daintree River Crossing – Options Assessment Report released in August 2020. (see References below). According to estimates, the lowest cost bridge option would be around $53 million with the other options being considerably more. The two ferry option will only cost $2.8 million and this will be rapidly recovered through ferry charges.
daintree river


ANDRE LEU


⟼ The lowest cost bridge option is approximately $53 million, with the other options considerably higher.
⟼ The two-ferry option will only cost $2.8 million, which will be rapidly recovered through ferry charges.
⟼ Negative impact of a bridge damaging one of the Douglas Shire’s important ecotourist industries
⟼ Damage to unique ecosystems has been ignored in the Report


Executive Summary and Conclusions


This article investigates the costings and issues associated with the four bridge options presented in Douglas Shire Council’s Daintree River Crossing – Options Assessment Report released in August 2020. (see References below). According to estimates, the lowest cost bridge option would be around $53 million with the other options being considerably more. The two ferry option will only cost $2.8 million and this will be rapidly recovered through ferry charges. Even the lowest cost bridge will be a massive cost for Douglas Shire rate payers. The Options Assessment Report states that a bridge without a toll would result in a 6.1% increase in general rates. A toll will require a special permission from the State Government. The 6.1% increase will be higher if the Council has to borrow money as the Report assumes that the Council does not borrow money to fund the bridge, and therefore would receive government grants.
It is highly unlikely that the State and Federal Governments will fund a bridge given that only a few hundred residents live north of the Daintree River and only 5% said they wanted the bridge option in the extensive public consultation undertaken by the previous Council. Governments would not spend such large sums of money for the benefit of so few people. Especially, when there is substantial local, national and international opposition to building it.

The concept of a Daintree River bridge is already highly controversial.

  • The two lowest cost options, Martinelli Road and 2874 Mossman Daintree Road require the destruction of numerous native trees in unique ecosystems, and these options should be strongly opposed on these grounds alone.
  • The huge cost and extra travel time makes the Daintree Village bridge option completely pointless.
  • A bridge has the potential to do considerable damage to the valuable river and rainforest ecotourism industry.
  • The image of a low level concrete bridge with constant noisy traffic is inconsistent with the pristine nature of the riverine wilderness experience.
  • By contrast, the ferry, is seen as an integral part of this wilderness experience.

Introduction


The Douglas Shire Council’s ‘Daintree River Crossing – Options Assessment Report’ gives the costs of the four bridge options as between $53 and $75 million with the average of $60 million compared to the double ferry option of $2.8 million.

The Report does not provide a cost breakdown of each option. It only gives construction costs such as $10,000 per square metre for a bridge and $750,000 per kilometre to construct new roads.
The bridge will be a low level pier and beam concrete bridge similar to the Bloomfield River bridge. This type of bridge is the cheapest option and can produce numerous problems in a river like the Daintree.

The Bloomfield River Bridge above is an example of the type of bridge proposed to be built over the Daintree River. This type of bridge is inappropriate for the Daintree and will cause numerous problems. Source: Google Pictures

NOTE: We have received expert advice that the Council estimated costs of $10,000 per square metre for a pier and beam concrete bridge and $750,000 dollars per kilometre to construct new roads are conservative, and that the budgeting costs could be considerably higher.


However, this article examines the costs and other associated issues for each of the four bridge options, based on the figures provided in the Options Assessment Report, and assume that the bridge costs come in on-budget and not over-budget. The figures are rough estimates based on map measurements ‘as the crow flies’ – the real distances would be slightly different. However, they are approximate enough to achieve an understanding of the minimum costs and other issues for each of the options. These types of complex construction projects usually run over budget, and over time.

Map showing the four Daintree River crossing bridge locations and the existing roads

OPTION 1 / Bridge at Daintree Ferry Crossing

13 metres wide X 300 metres long X $10,000 per square metre = $39 million

(300 metres is the longest bridge length used in the report)
+ 20% consultancy fee = $7.8 million
+ 40% contingency cost= $15.6 million


Bridge Cost = $62.4 million


Roadworks


There will be a need for extra roadworks on both sides of the Daintree River for bridge access, presumably similar to the $2.8 million needed for the second ferry, especially if there is a toll on the bridge, however these are not detailed in the Report.


Unknown Extra Costs


It is highly likely the Council will have to buy the block of land on the north bank so that they can build the bridge to minimise the interruption of the ferry operation. Along with the cost of roadworks, this is an unknown cost, adding to a higher estimate than the minimum cited above.


Tourism Impact

A low-lying concrete bridge with constant traffic would have a considerable negative impact on the vital ecotourism industry that showcases the diverse wildlife and habitats of the Daintree River and Daintree Coast.

Many people regard these types of bridges as ugly and would regard it as an eyesore that is a blight on the visual beauty of the river and its highly diverse riparian forests. The Daintree tour boat industry is a globally renowned major tourist drawcard, employer and income generator for the Douglas Shire. It will be adversely affected because the image of the bridge is inconsistent with the pristine nature of the riverine and rainforest wilderness experience and has the potential to impact considerable damage on this valuable ecotourism industry. By contrast, the ferry, is seen as an integral part of this wilderness experience.
Furthermore, the four-metre height, and piers in the river would prevent most masted vessels from travelling upstream from the current ferry crossing. The river has always been navigable to Daintree Village – this will sadly be lost.


Total Costs


The minimum cost of an on-budget project is $62.4 million plus the cost of road works, buying and resuming land.


OPTION 2 / Bridge at Martinelli Road



13 X 260 X $10,000 = $33.8 million
+ 20% Consultancy = $6.76 million
+ 40% Contingency = $13.52 million


Bridge Cost = $54.08 million


Roadworks


There is a need to construct a sealed road along the 1.8 kms of Martinelli Rd at $750,000 per km = $1.35 million. The costs will most likely be significantly more due to terrain difficulties. Martinelli Road passes through a unique and endangered wetland. This part of the road is regularly flooded during the wet season, so will need to be raised by several metres.


The last 280 metres of Martinelli Rd features high quality riparian forest that drains into the river, with no formed road. Forming the road at this section requires the destruction of this vegetation. The road will need to be raised by a few metres and will require substantial drainage to be constructed — otherwise the adjoining cane land will be too waterlogged to grow sugar cane.
On the northern side the council will need to construct 1.2 kms of new road to join the 1.47 kms of eastern arm of Forest Creek Road.

The existing 5.24 kms of Forest Creek Road, including the 2.7 kms of sealed road, will need to be substantially reconstructed to cope with the considerably increased traffic and heavier loads.
The estimated cost for the 7.91 kms of roads to the corner of Cape Tribulation and Forest Creek Roads at $750,000 per kilometre is $5.9 million.

Much of the new 1.2 km section will need extensive building-up and drainage as it goes over low lying areas that become boggy and waterlogged in the wet season. We have received expert advice is that it will cost substantially more than the average estimate of $750,000 per kilometre.


Unknown Costs


Council will be required to buy and resume land for the 1.2 km road extension.


Environmental Issues


A critical environmental issue is ignored by the Report.

Martinelli Road passes through a unique wetland that contains the only stand of Melaleuca cajuputi subsp. platyphylla in the Wet Tropics bio region. Melaleuca cajuputi occurs from Myanmar, Thailand and Vietnam, through Indonesia, PNG, down to Cape York and across to the Kimberleys. The subspecies Melaleuca cajuputi subsp. platyphylla only occurs from New Guinea to Cape York, with a few isolated trees found as far south as near Cairns. The Daintree population is the most southern stand in the world and is in a degraded condition because of the invasion of para grass, molasses grass and hymenachne, the construction of dirt roads, and artificial and impeded drainage. The wetland also contains two undescribed waterlily species, that are examples of the first primitive flowering plants and are now smothered by the exotic grass species.


Building a raised, high-traffic volume, two lane road through this unique and threatened wetland will further add to its degradation. Council instead should be working in partnership with the land owners on a voluntary agreement to regenerate this precious and unique wetland ecosystem rather than further degenerating it.

The bridge will require the removal of highly diverse riparian forests on both sides of the river. The environmental damage alone should be enough of reason for never constructing a bridge and road along Martinelli Road.

Total Cost


The minimum cost of an on-budget project is $61.33 million plus the cost of buying and resuming land.

Martinelli Road traverses the unique Melaleuca cajuputi subsp. platyphylla wetland. The rare trees will need to be cleared to raise and widen the road.

OPTION 3 / Bridge Adjacent to 2874 Mossman Daintree Road


13 X 190 X $10,000 = $24.7 million
(190 metres is the shortest bridge length used in the report)
+ 20% Consultancy = $4.94 million
+ 40% Contingency = $9.98 million


Bridge Cost = $39.62 million


Roadworks


There will be a need for a new intersection with passing lanes similar to the current intersection at the corner of Cape Tribulation and Mossman-Daintree Roads.

$1.5 million is a conservative estimate.

The cost for a smaller turn-off for the proposed Paws and Claws refuge near at Yule Point is a similar estimate, and this cost was one of the reasons why the development did not proceed on that site.
The intersection will be further complicated by the need to accommodate tourists being able to drive safely in and out of Belcher’s ecotourism business and for nearby residents to drive safely in and out of their driveways, due to the higher volume of traffic.


A new road will need to be built on the northern side of the river. The shortest route to Forest Creek Road is 1.35 kms of unformed gazetted esplanade on the bank of Brandy and Water Creek. Most of this esplanade is forested riparian vegetation essential to ensuring the stability of the creek bank. Clearing this high value ecosystem for a road will cause a range of serious adverse environmental issues, as riparian vegetation should never be cleared. Building a road along this esplanade should be opposed for the environmental damage it will cause. It is highly unlikely the Council would be able to get a permit to do this.


An alternative route is for the Council to construct 1.2 kms of new road to join the 1.47 kms of the eastern arm of Forest Creek Road. This is a different route to Martinelli Road option however it will traverse similar terrain and have similar requirements to make it serviceable all year round.
The minimum cost for the 7.91 kms of roads to the corner of Cape Tribulation and Forest Creek Roads at $750,000 per kilometre is $5.9 million.


Unknown Costs


Buying and resuming land for 1.2 km of new road on the northern side to connect with Forest Creek Road.


Tourism Impact


The proposed bridge would be located between two major river-cruise ecotourism ventures. The low-lying concrete bridge with constant traffic will be perceived as a noisy eyesore in the environment and would have a negative impact on these businesses and the other tour boat operators on the Daintree River.


Environmental Issues


The shortest route will require the clearing of 1.35 kms of riparian forest. The bridge alone will require the removal of 20 metre tall, highly diverse riparian forests on both sides of the river. It should be opposed for this reason alone.

Total Cost


The minimum cost of an on-budget project is $47.02 million plus the cost of buying and resuming land for 1.2 km of new road on the northern side to connect with Forest Creek Road.


The 20 metre tall highly diverse riparian forest that will need to be cleared at 2874 Mossman Daintree Road

OPTION 4 / Bridge at Daintree Village


13 X 190 X $10,000 = $24.7 million
(190 metres is the shortest bridge length used in the report)
+ 20% Consultancy = $4.94 million
+ 40% Contingency = $9.98 million


Bridge Cost = $39.62 million


Local Road Flooding


The bridge at Barratt Creek regularly floods, sometimes for days, isolating Daintree Village. The current ferry runs during the Barratt Creek bridge flood events except in the most extreme of floods. Residents north of the Daintree River will be worse off in terms of access, with a Daintree Village bridge, unless a new flood free bridge is built at Barratt Creek.


There is a need to build a new higher bridge at Barratt Creek to the same standard and the same river height of four metres, as the Daintree Village bridge, given the significantly high traffic volumes that will use it. This will require 440 metres of higher road approaches over the creek.
The following scenario assumes that 340 meters of road can be built up and only 100 meters of a bridge is constructed of the same design cost criteria as the Daintree River bridge.

New Barratt Creek bridge 13 X 100 X $10,000 = $13 million
+ 20% Consultancy = $2.6 million
+ 40% Contingency = $5.2 million


Bridge Cost = $20.8 million


Roadworks


There will be a need for a new intersection with passing lanes similar to the current intersection at the corner of Cape Tribulation and Mossman Daintree Rd in the entrance of Daintree Village. $1.5 million is a conservative estimate.
The Council will be a need to resume 300 metres of private property for the road and bridge on the Daintree Village side of the river. Land will need to be resumed from six properties on the northern side to build 3.4 kms of new road to join Forest Creek Road. The Council will need to construct and upgrade 12.4 kms of road to reach the corner of Cape Tribulation and Forest Creek Roads. 12.4 kms X $750,000 per km = $9.3 million.


Unknown Costs

The need to raise the Barratt Creek bridge road access to four metres so that it is the same level of the Daintree Village Bridge crossing and will not be subject to regular flooding will require significantly more funding than the standard $750,000 per kilometre that was proposed in the budget. A conservative estimate of $2 million is added to this scenario, however the real costs are unknown until a detailed engineering report is completed.
The Council will need to resume 300 metres of private property for the road and bridge on the Daintree Village side of the river. As well as resuming this property, land will need to be resumed from six properties on the northern side to build 3.4 kms of new road to join Forest Creek Road.


Other Issues


The Daintree Village bridge, as well as being the most expensive option, will add more than 17.7 kilometres to the travel journey compared to the current ferry option. This would mean longer journey times overall, compared to the two ferry option. It would also be extremely unfair for the children who live north of the river as they would have to endure an extra 35.4 kilometres of travel every day in the school bus. The extra travel required for all traffic will result in significant amounts of greenhouse gas emissions compared to the proposed ferry that will be substantially powered by renewable solar energy. The huge expense and extra travel time makes this option completely pointless.


Total Cost

The minimum cost if the project is on budget is $73.22 million plus the cost of buying and resuming land.

Conclusions

The cost, economic and environmental considerations show that each of the bridge options will have negative impacts compared to the two-ferry solution.

The two-ferry option is the cheapest and most timely to complete, compared to any of the bridge options.

Source: Google Images

References

Think Different. Think DouglasNews.Network.

Your support matters. Support from our readers helps protect our editorial independence. Help us to report fearlessly on issues that affect our region, and to challenge those in power. Help us continue to deliver quality, trustworthy, fact-checked journalism that is free to access.

Please make a donation today.