ii6 W. A. JOHNSTON 



FRASER RIVER AND ITS RECENT DELTA 



The Fraser River is the largest river in British Columbia whose 

 basin lies entirely within the province. It has a length of 790 

 miles and drains an area of 91,700 square miles. The maximum 

 discharge of the river at Hope (100 miles above its mouth) for the 

 past nine years, as determined by the Dominion Water Power 

 Branch of the Department of the Interior, was in July, 1920, when 

 it amounted to 380,000 c.f.s. During the great flood of 1894, 

 however, the discharge as estimated by officials of the Department 

 of Public Works was nearly 500,000 c.f.s. The average minimum 

 discharge of the river at Hope for the past nine years was 17,000 

 c.f.s., the lowest being 12,000 c.f.s. There is thus considerable 

 variation from high to low water in each year. The water usually 

 begins to rise in May and reaches its greatest height in June or 

 July. Extreme low water may occur in any month from November 

 to March. During the low-water period the river is affected by 

 ocean tides for a distance of 60 miles above its mouth. The 

 current is reversed in the river by the flood tide, however, only for 

 30 miles above the mouth. The tides in the Strait of Georgia are 

 declinational in character and are characterized by marked diurnal 

 inequality of the semidaily tides. The mean range at the mouth 

 of the Fraser River is 6.4 feet. The maximum range of the great 

 flood tides is 15 feet and of the great ebb tides 14 feet. These 

 maximum ranges, however, are rarely reached, the average for the 

 large tides — which occur for a few days twice a month near the 

 time of maximum declination of the moon — being about 12 feet 

 for the ebb tides and 13 feet for the flood tides. During the 

 balance of the month the ranges are less. The fact that the river 

 is tidal for a considerable distance above its mouth renders it 

 navigable; for the lack of river water during the low- water stage 

 of the river is largely compensated by the tidal water. The 

 combined ebb-tidal and river discharge of the river, in the main 

 channel near its mouth, is rarely less than 100,000 c.f.s., even 

 during the extreme low-water stage of the river. 



The water of the Fraser River is turbid to some extent through- 

 out the year, and is markedly so during freshets; but the amount 

 of material carried in suspension is comparatively small. The 



