Estimating the hydrographic effects of Prudhoe Bay causeway breaches using the Before-After Control-Impact (BACI) analysis. Arctic 54(2

• Main Authors: Robert G. Fechhelm, Larry R. Martin, Benny J. Gallaway, William J. Wilson, William B. Griffiths
• Other Authors: The Pennsylvania State University CiteSeerX Archives
• Format: Text
• Language: English
• Published: 2001
• Subjects: Arctic; Prudhoe Bay
• Online Access: http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.536.9027; http://pubs.aina.ucalgary.ca/arctic/Arctic54-2-162.pdf

ABSTRACT. A Before-After Control-Impact (BACI) analysis was used to test the effects of new breaches constructed in two Prudhoe Bay causeways on hydrographic conditions during the open-water summer season. At West Dock, under east wind conditions, significant cross-causeway differentials in salinity and temperature at the surface (1 m depth or less) were observed in all eight pre-breach cases tested. In the years following construction of the breach, there were no significant cross-causeway differentials in seven of those eight cases. At Endicott Causeway, under east wind conditions, significant cross-causeway differentials in surface salinity and temperature were observed in all eight pre-breach cases tested. Significant cross-causeway differentials continued in all eight cases following construction of the new breach. Results suggest that the new breach at West Dock has successfully mitigated cross-causeway hydrographic differentials, and that the new breach at the Endicott Causeway has had no observable effect. The possible reasons for this disparity include different hydrographic dynamics in the vicinity of each causeway. Key words: breaching, causeways, hydrography, mitigation, Prudhoe Bay, water quality RÉSUMÉ. On a procédé à une analyse de contrôle-incidence avant-après pour tester les effets de nouvelles brèches aménagées dans deux ponts-jetées de la baie Prudhoe sur les conditions hydrographiques durant la saison estivale d’eau libre. Au West Dock, par vent d’est, on a observé des écarts notables de part et d’autre du pont-jetée dans la salinité et la température de surface (jusqu’à 1 m de profondeur) dans les huit tests effectués avant l’aménagement de la brèche. Au cours des années suivantes, on n’a relevé aucun écart notable de part et d’autre du pont-jetée dans sept de ces huit cas. Au pont-jetée Endicott, par vent d’est, on a relevé d’importants écarts dans la salinité et la température de surface dans les huit tests