The partial bridge span on the causeway and the difference between a "bridge issue" and an "environmental issue"

By Daniel LeBlanc
Petitcodiac Riverkeeper

On March 14, our organisation released a document entitled 'A Discussion Paper on Restoration Options for the Petitcodiac River'.

Our intention is to generate discussion, interest and feedback in our community to the subject of the Petitcodiac River system and the Shepody Bay estuary, to the effects of the Petitcodiac River causeway on our eco-system, and to the options available in order to restore free flow in the Petitcodiac River system.

Through the exercise we also wish to offer the public a comprehensive set of economic, social and environmental tools to enable them make their own informed decision on the Petitcodiac River restoration issue.

Since releasing the document last week, a number of good questions have been presented to us, dealing with the logic behind the 250 m length, the costs and benefits associated with this option, and the timeframe envisaged. This column will respond in part to these issues, but we encourage those who have access to the internet to download a free copy of the document at www.petitcodiac.org, or else send us a $5 cheque with your address to Box 300, Moncton.

1) Why 250 meters?

The 250 m bridge span option proposed by ADI Ltd. (the causeway is 1 km long), is the length established to restore approximately 100 % tidal exchange through the structure, based on hydrological estimates done in a 1992 ADI Ltd. study. Obviously, this figure could change a bit once detailed research is done to prepare for this restoration option.

Reaching the "approximately 100 %" tidal exchange objective is often used by engineers and hydrologists when establishing parameters to "fully restore" river systems. In other words, even though the Petitcodiac River is approximately 1 km wide at that junction, very few engineers and hydrologists would have as an objective to fully replace the structure.

2) How much will it cost?

One way of answering this question is to say: it depends on how you look at it. The partial bridge span option lists 7 quantifiable gains, from savings related to the non-operation of the causeway gates, to the savings linked to improved drainage conditions, to the restoration of commercial and sport fishing opportunities in the river system.

For those wondering about dollar figures, bearing in mind that these are 1992 numbers projected on a 10 year timeline, the paper conservatively estimates these gains at between $2.7 and $6.7 million.

The partial bridge span option also lists 20 intangible benefits, from the recovery of 21 km of estuary upriver, to the generation of international goodwill created by the recovery of the eco-system and the Petitcodiac River tidal bore. Just how much this is all worth depends, again, on how you value these.

On the expenditure side, the paper suggests that total costs of this option are in the $18.5 to $19.5 million dollar range, approximately half of it representing costs associated with the construction of the partial bridge span, and the rest addressing issues of erosion protection, causeway operation and marshland purchases.

Leaving these numbers aside for a moment, I find that a better way to understand the implications of costs and benefits associated with the partial bridge span option is to compare all of these figures with similar restoration initiatives happening locally and around the world. From this perspective, the issue becomes a 'restoration or environmental issue' more so than a 'bridge issue'.

Many examples of environmental restoration or clean up projects exist nationally and internationally to help us compare. The $12 million clean up project of the old CN properties in Moncton is one such example initiated, I imagine, in order for present and future generations not to inherit a legacy of environmental devastation and waste.

Another example of a restoration project, which is before the U.S. Congress, is a US$ 7.8 billion, 20 year project to restore a more natural water flow to the Florida Everglades. It is an enormous undertaking, but here again, I imagine that whether you would support such a measure depends very much on how you value the idea of restoring the Everglades.

3) What's the timeline?

The timeline envisaged to complete the partial bridge span option is a period between 3 and 5 years. This applies from a planning, a cash flow and an environmental restoration perspective. This is also called a phased approach to restoration.

During the first years, the gates of the causeway structure are opened to allow normal estuary functions to be restored, the channel down river to be widened, and the banks of the headpond to be solidified. This is also the time when the planning and the construction of the partial bridge span takes place.

From a traffic management point of view, it surely helps if the new bridge replacing the old Gunningsville one is fully operational. We have said in the past that we support the new bridge proposal at the Gunningsville site for three reasons: 1) concerns of the Halls Creek bridge interfering with the Petitcodiac River Tidal Bore, 2) the possibility of conserving the old bridge as a pedestrian way, and 3) the savings incurred with the Gunningsville choice being directed to finance the partial bridge span option.

We look forward to discussing any of the above with the community.

Daniel LeBlanc is the Executive Director of the Sentinelles Petitcodiac Riverkeeper, a non-profit organisation working for the restoration, the preservation and the protection of the Petitcodiac River system and the Shepody Bay estuary in south-eastern New Brunswick.