Journal of Marine Research, Sears Foundation for Marine Research
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The Journal of Marine Research is an online peer-reviewed journal that publishes original research on a broad array of topics in physical, biological, and chemical oceanography. In publication since 1937, it is one of the oldest journals in American marine science and occupies a unique niche within the ocean sciences, with a rich tradition and distinguished history as part of the Sears Foundation for Marine Research at Yale University. Past and current issues are available at journalofmarineresearch.org. Yale University provides access to these materials for educational and research purposes only. Copyright or other proprietary rights to content contained in this document may be held by individuals or entities other than, or in addition to, Yale University. You are solely responsible for determining the ownership of the copyright, and for obtaining permission for your intended use. Yale University makes no warranty that your distribution, reproduction, or other use of these materials will not infringe the rights of third parties. This work is licensed under the Creative Commons Attribution- NonCommercial-ShareAlike 4.0 International License. To view a copy of this license, visit http://creativecommons.org/licenses/by-nc-sa/4.0/ or send a letter to Creative Commons, PO Box 1866, Mountain View, CA 94042, USA. Journal of Marine Research, Sears Foundation for Marine Research, Yale University PO Box 208118, New Haven, CT 06520-8118 USA (203) 432-3154 fax (203) 432-5872 [email protected] www.journalofmarineresearch.org SOME OCEANOGRAPIDC CHARACTERISTICS OF A POLLUTED INLET IN BRITISH COLUMBIA MICHAEL WALDICHUK Fi8heriea Research Board of Canada Biological S1.ation, Nanaimo, B.G. ABSTRACT Physical and chemical characteristics of Neroutsos Inlet, British Columbia, in August 1957 are described. Moderately deep, II nautical miles long by 0.5 to l mile wide, it has been subjected to a prolonged period of waste disposal from a sulphite pulp mill near its head. The mill effluent is discharged on the surface at the shore and is largely confined to a thin surface layer about 5 m deep . Low dissolved oxygen in surface water was noted and virtual extinction of intertidal flora and fauna within several miles of the mill apparently has occurred. Absence of significant vertical mixing allows the deep water to remain relatively free of contamination. The Inlet lacks the m echanism of a large runoff from the head for rapid flushing of wastes released at the surface. Comparison of oceanographic data collect ed in Neroutsos Inlet during August 1927 with those of August 1957 suggests that there has been a long-term change in conditions as a result of 40 years of continuous discharge of mill wastes into Inlet waters. INTRODUCTION Neroutsos Inlet is the southeast arm of Quatsino Sound, on the northwest side of Vancouver Island (Fig. I). It has a northwest- southeast axis parallel to the main trend of the coastline, running from Lat. 50°20' N to 50°30' N. Shaped like a typical British Co- lumbia fjord (Pickard, 1956), it is long and narrow with steep moun- tainous sides. It is 11 nautical miles long, divided into a deep section 7½ mi long and 1 mi wide from its mouth to Ker Point and a shal- low section 31/i mi long and ½ mi wide from Ker Point to its head. A cross-section of the Inlet is U-shaped with depths slightly greater than 100 fathoms along mid channel. It has no significant sills, but it is somewhat constricted laterally and vertically at Ker Point, where the effective width is less than 0.3 mi and the depth is only 20 fathoms. In Table I are given some of the morphometric char- acteristics of the Inlet. (536) 127 40' SCALE IN NAUTICAL MILES 50 - Fothom depth-·---·- ·- ·- 100- folhom depth-··- ·· - ·· - ·· - ·· 50.North Lal CoyeQhlt Cr. Figure l. Chart of Neroutsos Inlet and adjoining waters of Quatsino Sound showing oceanographic stations occupied during August 1957. Inset : Chart of Vancouver Island featuring the general location of Quatsino Sound. 538 Journal of Marine Research [17 TABLE I. MORPHOMETRIC CHARACTERISTICS OF NEROUTSOS INLET Dimension Common Units Metric Units Length from mouth at Pender Pt. to Ker Pt. 7. 70 n mi 14.27 km Length from Ker Pt. to head at Cayeghle Cr. 3.50 n mi 6.49 km Average width of segment from Pender Pt. to Ker Pt. 0.91 n mi 1.69 km Average width of segment from Ker Pt. to Cayeghle Cr. 0.4 7 n mi 0.87 km Mean depth 48.1 fm 88.0 m Mean large tidal range 9.5 ft 2.90 m Mean small tidal range 6.0 ft 1.83 m Mean tidal prism on large tidal range 0.0140 (n mi)8 0.0890 km• Mean tidal prism on small tidal range 0.00886 (n mi)8 0.0563 km• Horizontal areas : ,-Area~ ,- Area --, Depth Contour Depth Contour (nmi)2 km2 (n mi)2 km' Surface* 8.944 30.77 50 fathoms 4.022 13.84 10 fathoms 6.990 24.05 60 3.469 11.93 20 6.285 21.62 75 2.708 9.315 30 5.146 17.70 90 1.822 6.268 40 4.631 15.93 100 1.076 3.702 • Mean high water. Cross-sectional areas: ,--Area---, Section (n mi)" km2 From Pender Pt. to point west of Atkins Cove 0.0448 0.1540 From Nequiltpaalis Cr. to Goquawhenigh Cr. 0.0726 0.2495 From Port Alice to Cayuse Cr. 0.00393 0.01348 Across Inlet south of Ketchen Is. 0.00976 0.0335 Volumes: Depth I nterval ,-- Volume--, D epth Interval ,-- Volume ---.... (fathoms) (n mi)3 km3 (fathoms) (n mi)3 km' 0-10 0.0761 0.4838 60-70 0.0316 0.2007 10-20 0.0653 0.4153 70-80 0.0267 0.1699 20-30 0.0568 0.3612 80-90 0.0213 0.1353 30-40 0.0483 0.3070 90-100 0.0143 0.0912 40-50 0.0425 0.2706 100-110 0.0055 0.0352 50-60 0.0367 0.2334 Total 0.4251 2. 7036 Like most British Columbia inlets, it has a tributary stream at the head. Cayeghle Creek forms a silty delta at the southern end of the Inlet where winter freshets deposit most of the load eroded 1958) W aldichuk: Characteristics of a Polluted Inlet 539 from the rugged drainage basin. Its discharge is of the order of 50 cfs (1.4 m 3/sec) in midsummer, with much greater flows in winter when heavy rains give rise to a large runoff. Numerous streams dissect its margin but they contribute relatively small volumes of fresh water to the system. Compared to other B.C. inlets, the total volume of fresh water added to Neroutsos Inlet by runoff is small because of the confined area of the drainage basin. The steep slopes bordering this Inlet are heavily wooded. This makes the area attractive for logging, and forest products industries have been established there from early times. Meteorological conditions in Neroutsos Inlet are typically those of the west coast of Vancouver Island. Summers are moderately warm and dry, but a large winter rainfall augmented by occasional snow gives a mean annual precipitation of 115 inches (292 cm), measured at Port Alice. While the Inlet is sheltered from intense Pacific storms, it has its own wind regime, which can be quite intensive at times. Typical of B.C. inlets, there are strong up-inlet winds (northwesterly in this case) on warm sunny afternoons. During inclement weather, winds are southeasterly or down-inlet. POLLUTION SOURCE At Port Alice, on the east side of the upper section of the Inlet, a sulphite pulp mill has been in operation since 1917. Its production has varied from somewhat modest beginnings through a shutdown period of many months during the 30's to about 220 short tons per day by 1942. Output has continued into 1959 at the latter figure, excepting a few months of supension of production in 1957-58. In 1955, construction was commenced on an expansion of the mill to increase production by two thirds to approximately 370 tons per day (Waldichuk, 1956a). This mill employs a calcium base in its cooking process, and wastes pass untreated into the Inlet. Discharge of effluent, until 1957, was by way of a wooden flume. The outfall from which the wastes were released was about 15 ft above lower low tide, providing considerable mixing of effluent into the surface water. In 1957, a specially designed flume was installed to allow the effluent to dis- charge into the surface water with a minimum of mixing. The effluent from the mill has a flow of about 29,000 U.S. gallons per 540 Journal of Marine Research [17 minute (65 cfs, or 1.84 m 3/sec), the water for which is piped from Victoria Lake, located a few miles east of Port Alice. For every ton of pulp produced, one ton of organic substances that bind the wood fibers together, in addition to about 800 lb of chemicals used in the digestion, are passed into the receiving waters. The main cause of pollution is the high oxygen consumption during decomposition of the organic constituents. With an average of 650 lb of BOD (biochemical oxygen demand) per ton of sulphite pulp (Gehm, 1953 : 203), the oxygen demand for a daily output of 220 tons of pulp would be 14.3 x 104 lb (6.49 x 104 kg). METHODS AND DISTRIBUTION OF PROPERTIES A survey was conducted in Quatsino Sound August 15-20 with the ship CNAV EHKOLI. Regular oceanographic observations of salinity, temperature, dissolved oxygen and pH were made at stations shown in Fig.