Research Document - 2000/011

Hydrological conditions for Atlantic Salmon in 1999.

By D. Caissie

Abstract

This paper provides 1999 and historical information on hydrological conditions for 6 selected Atlantic salmon (Salmo salar) rivers within the Maritime Provinces. High and low flows for each river were calculated based on historical annual high and low flow series. Air temperature data was presented for 6 stations in the Maritime Provinces. Stream water temperatures were reported in 3 river systems as well as high temperature events.

Discharges were excessive for most rivers in the winter of 1999 (January and March). Record high monthly flows were observed in March in St. Marys River (NS). The spring breakup of 1999 was early with peak flows in March. The spring breakup was generally characterized as mild with most rivers having floods less than a 2-year flood event. Upsalquitch River and Northeast Margaree River experienced the highest flood peaks close to the 5-year flood.

The early spring flood in 1999 resulted in low flow in June and July. Deficient monthly flows were observed in all rivers during these two months and record low monthly flows were monitored in both Wilmot River (PEI) and Northeast Margaree River (NS). On a daily basis, most rivers did not fall to the 2-year low flow this year. Southwest Miramichi River and Northeast Margaree River were the most affected in terms of low water conditions and they reached a 10-year low flow event.

River water temperatures in 1999 were characterized by five events between mid- June and late-August. Nashwaak, Little Southwest Miramichi, Tobique and Tomogonops Rivers all reached peak temperature exceeding 29 C in 1999. These high water temperatures were the result of the highest summer air temperature on record in the Maritime Provinces (data going to 1940s). The number of days with river water temperatures exceeding 23 °C, more than doubled this year. The most affected river was the Nashwaak River with 67 days of temperatures exceeding 23 °C. Of the 15 studied rivers, 7 rivers showed over 50 days with high temperatures (> 23°C).

Complete document (PDF, 2804 KB)

Accessibility Notice

This document is available in PDF format. If the document is not accessible to you, please contact the Secretariat to obtain another appropriate format, such as regular print, large print, Braille or audio version.