Canadian Wildlife Service Technical Report Series No. 334

[Note: only the abstract, resumé, table of contents, summary
and conclusions, and recommendations are included below.]

Paper copies may be obtained from:

ABSTRACT

A wide range and number of barriers exist on rivers that drain into the Bay of Fundy, both upstream and on their estuaries. Barriers can be defined as any structure built into, through or over a waterway (stream, creek, river, estuary) that changes, possibly irreversibly, the physical (e.g. sedimentation, water circulation), chemical (e.g. salinity, oxygen, trace elements), biological (e.g. fish behavior) or ecological (e.g. production) characteristics of that waterway. Tidal barriers are obstructions constructed in or across a tidal water body that changes the tidal fluctuation in all or part of the water body above the obstruction. Barriers on Bay of Fundy rivers and their estuaries include dykes, aboiteau, causeways (with bridges, culverts and dams), dams and wharves. An ad-hoc Environment Canada working group was established in 1997; it convened to summarize what was known about the location, number, type, impacts and remediation potential associated with Fundy

barriers. This report presents the working groups findings. Barriers exist on at least 25 of 44 major rivers around the Bay of Fundy. They have caused or are thought to have caused a wide range of ecological effects on the rivers themselves and their estuaries around the bay. These include: reduced lengths of tidal rivers, changed freshwater discharges, reduced movement of saltwater upstream, changed hydrodynamics, sedimentation (often severe), reduced open salt marsh, reduced nutrient transfer to the Bay, and interference with the movement of fish and invertebrates. However, the full scope of environmental impacts is not well understood at the present time; except for a few rivers and their estuaries, our data are largely anecdotal. It is recommended that federal agencies, provincial departments and other groups and interested parties consider strengthening the data and information base on barriers, update river flow information, model changes and cumulative effects, and determine the effects of rehabilitation or remediation efforts on selected river barriers.

RÉSUMÉ

Les rivières qui se jettent dans la baie de Fundy comportent un grand nombre d’obstacles divers, tant dans leurs cours supérieurs que dans leurs estuaires. Par obstacle, on entend ici toute structure aménagée au sein, en travers ou au-dessus d’un cours d’eau (fleuve, rivière, ruisseau ou estuaire) qui modifie, parfois irréversiblement, les caractéristiques physique (p. ex. sédimentation et circulation de l’eau), chimiques (p. ex. salinité, oxygène, éléments traces), biologiques (p. ex. comportement du poisson) ou écologiques (p. ex. production) du cours d’eau. Les obstacles à la marée qui modifient le flux de marée dans la totalité ou une partie des eaux en question, en amont de ces obstacles. Dans les rivières de la baie de Fundy et leurs estuaires, ces obstacles comprennent les digues, les aboiteaux, les chaussées (dotés de ponts, de buses et de barrages), les barrages et les quais. Un groupe de travail spécial a été mis sur pied par Environnement Canada en 1997; il a dressé un inventaire des données connues sur l’emplacement, le nombre et le type de ces obstacles, ainsi que sur leurs incidences et sur les mesures correctives possibles. Le présent rapport expose ses constations. Sur 44 grandes rivières de la baie de Fundy, au moins 25 comportent des obstacles. On sait ou on pense que ceux-ci ont eu des incidences biologiques nombreuses et variées sur les rivières elles-mêmes et sur leurs estuaires. Ils ont, notamment, diminué la longueur des rivières, modifié l’écoulement d’eau douce, réduit l’apport d’eau salée en amont, modifié l’hydrodynamique et la sédimentation (souvent gravement), rétréci les marais littoraux, réduit le transfert de matières nutritives vers la baie et gêné la migration des poissons et des invertébrés. Toutefois, on ne saisit pas très bien actuellement toute la portée des incidences environnementales; exception faite de quelques rivières et de leurs estuaires, nos renseignements; exception faite de quelques rivières et de leurs estuaires, nos renseignements sont très anecdotiques. On recommande que les organismes fédéraux, les ministères provinciaux, d’autres groupes et les parties intéressées envisagent d’accroître la base de données et de renseignements sur les obstacles, mettent à jour les données sur le débit des cours d’eau, modélisent les changements survenus et leur effets cumulés, et déterminent les effets des mesures ou de réparation dans certaines rivières obstruées.

TABLE OF CONTENTS

ABSTRACT ............................................................................................................................i
RÉSUMÉ................................................................................................................................ ii
ACKNOWLEDGMENTS......................................................................................................... iii
TABLE OF CONTENTS ......................................................................................................... iv
LIST OF TABLES AND LIST OF APPENDICES .................................................................... v
SOME THOUGHTS ............................................................................................................... vi
1. INTRODUCTION ........................................................................................................... 1
2. BACKGROUND TO THE WORKING GROUP’S REVIEW OF THE ISSUE ................. 2
          2.1 Overview............................................................................................................... 2
          2.2 Literature Summary ..................................................................................... 3
3. EARLY CHANGES TO RIVERS AND LAND AROUND THE BAY OF FUNDY ............. 6
          3.1 Dykes and Dykelands .................................................................................. 6
          3.2 Log Dams and Power Dams ........................................................................ 6
          3.3 Land Use in the Watersheds of Fundy Rivers ............................................. 7
4. IMPACTS OF BARRIERS ON RIVERS ENTERING THE BAY OF FUNDY
(1950s to late 1990s)..................................................................................................... 7
5. BAY OF FUNDY CASE STUDIES AND OTHER COASTAL EXAMPLES ..................... 20
          5.1 Bay of Fundy ............................................................................................... 20
          5.2 Other Atlantic Coastal Locations ................................................................. 20
          5.3 Other Watersheds and Coasts .................................................................... 21
6. SUMMARY AND CONCLUSIONS ................................................................................ 22
7. RECOMMENDATIONS ................................................................................................. 22
BIBLIOGRAPHY ....................................................................................................................23
APPENDICES ..................................................................................................................... 28
          Appendix 1 Members of Working Group ....................................................................... 28
          Appendix 2 Additional Information on Impacts of Barriers............................................. 29
          Appendix 3 Notes and additions from the 1997 Workshop ........................................... 33

LIST OF TABLES
1. Summary of status of barriers on New Brunswick rivers that flow into the Bay of Fundy
2. Summary of status of barriers on Nova Scotia rivers that flow into the Bay of Fundy
3. Man-made barriers on medium and large rivers flowing into the Bay of Fundy
4. Functions of barriers and presence of fishways on rivers flowing into the Bay of Fundy

LIST OF APPENDICES
1. Members of Working Group
2. Additional Information on Impacts of Barriers
3. Notes and additions from the 1997 Workshop

6. SUMMARY AND CONCLUSIONS

Given the importance and many values of the living resources and ecology of the rivers and estuaries of the Bay of Fundy, there is a clear need to consider the barriers issue in depth. Barriers, especially dams, causeways and dykes, exist on at least 25 of 44 major Bay of Fundy rivers. They have caused or are thought to have caused a wide range of ecological effects on the rivers themselves and their estuaries around the bay. These include: reduced lengths of tidal rivers, changed freshwater discharges, reduced movement of saltwater upstream, changed hydrodynamics, sedimentation (often severe), reduced open salt marsh, reduced nutrient transfer to the Bay, and interference with the movement of fish and invertebrates. Effects on some systems are becoming understood with time and effort e.g. the Petitcodiac, Avon and Annapolis Rivers and their estuaries. However, the full scope of environmental impacts of most of the barriers, alone and together, and the potential benefits of remediation efforts, are not well understood at the present time. This is due in part to the complexity and inter-disciplinary nature of the problem(s), the low profile of the issue generally (the Petitcodiac and Annapolis Rivers being obvious exceptions), and the shortage of resources to study the problem in an integrated manner in the depth that it deserves. At the very least, we should re-examine and strengthen the information on the condition of individual rivers and the Bay of Fundy as a whole, and consider the options for action.

7. RECOMMENDATIONS

Several actions should be considered by the appropriate federal and provincial natural resource, transportation/highway and energy agencies, and all interested parties and stakeholders, at their earliest convenience:

5) Conducting a Pilot Project on Selected Rivers and Species: given the number of habitats and species across all rivers and estuaries in the Bay of Fundy, and the need to simplify an approach to quantifying impacts and effects of remediation, one project could be "to explore the usefulness of an index river/species approach to identifying the impacts of barriers on the living resources of the Bay of Fundy and the means of mitigation" (R. Bradford, pers. comm., 3/99).