Chapter 4 -- Watershed processes and aquatic ecosystems (continued)
The Smith River is a fifth order stream according to river reaches defined by the Environmental Protection Agency (EPA 1994). The North Fork, Middle Fork, and South Fork are fourth order streams. There are at least 325 first order streams in the watershed. Several gauging stations are (or were) located in the Smith River watershed (Tables 21 and 22).
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Table 21. Stream gauging stations in the Smith River system (California Dept. of Water Resources 1970). |
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|
Station name: |
Location description: |
|
Smith River |
0.5 miles downstream from South Fork and 8 miles east of Crescent City |
|
North Fork Smith River |
0.5 miles upstream from Middle Fork confluence |
|
Middle Fork Smith River |
0.6 miles upstream from North Fork confluence |
|
South Fork Smith River |
2 miles upstream from mouth |
|
Rowdy Creek |
0.6 miles south of the Smith River and 12.2 miles north of Crescent City |
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Table 22. Information about stream flow gauging stations in the Smith River watershed (Winston and Goodridge 1980, US Corps of Engineers 1971, California Department of Water Resources 1970, USGS 1997). |
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Smith River |
North Fork |
Middle Fork |
South Fork |
Mill Creek |
Rowdy Creek |
|
|
Period of record |
1931 - 93 |
1911 - 13 |
1911 - 17, 1958 - 65 |
1911 - 16, 1954 - 61, 1977 - 79 |
1974 - 81 |
1957 - 62 |
|
Drainage (sq mi) |
613.6 |
158 |
131 |
291 |
28.6 |
33.3 |
|
Elevation (feet) |
79 |
350 |
353 |
150 |
250 |
25 |
|
Avg runoff (in/yr) |
82.01 |
65.64 |
73.99 |
90.03 |
70.82 |
78.13 |
The Smith River watershed produces the highest runoff per area in California (Winston and Goodridge 1980). Average annual runoff for the entire basin is about 2.9 million acre feet. Like virtually all coastal rivers in the Pacific Northwest, the Smith River undergoes extreme variation in stream flow (Table 23). Stream flow is low during the summer and early fall and high during winter and spring. During the summer, base flows are low and fluctuations in flow are infrequent. Although annual variability is high, during a typical rainy season base flows are higher and there are occasional peak flows. Peak flows generally last for a few days and gradually decline. During the rainy season, daily and weekly fluctuations in stream flow are huge. Life stages of stream organisms are timed to take advantage of this flow regime.
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Table 23. Average monthly runoff at the Smith River gauging station from October 1, 1916 to October 1, 1966 (US Army Corps of Engineers 1971a). |
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Month |
Average runoff (acre/feet) |
Average flow (cubic feet/sec) |
Percent of annual runoff |
|
October |
73,000 |
1,200 |
3 |
|
November |
252,000 |
4,200 |
10 |
|
December |
423,000 |
6,800 |
16 |
|
January |
485,000 |
7,800 |
19 |
|
February |
407,000 |
7,000 |
16 |
|
March |
362,000 |
5,800 |
14 |
|
April |
276,000 |
4,600 |
10 |
|
May |
171,000 |
2,800 |
6 |
|
June |
74,000 |
1,200 |
3 |
|
July |
31,000 |
500 |
1 |
|
August |
20,000 |
300 |
1 |
|
September |
19,000 |
300 |
1 |
Over the last 10,000 years, regional climatic conditions have fluctuated, implying that flood regimes have also varied. Historical records and geologic studies indicate that major floods occurred on the Smith River about 1600, about 1750, December 1861, January 1890, February 1927, October 1950, January 1953, November 1953, December 1955, December 1964, and January 1966 (McCain et al. 1995, Tables 24 and 25).
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Table 24. Peak flows listed in order of magnitude on the Smith River near Crescent City, Del Norte County, California (US Army Corps of Engineers 1971a, USGS 1997). |
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|
Month and year |
Flow (cfs) |
|
December 1964 |
228,000 |
|
January 1972 |
182,000 |
|
December 1861 |
165,000 |
|
December 1955 |
165,000 |
|
January 1890 |
152,000 |
|
February 1927 |
152,000 |
|
October 1950 |
152,000 |
|
January 1966 |
145,000 |
|
November 1953 |
141,000 |
|
January 1953 |
139,000 |
|
March 1975 |
129,000 |
|
January 1971 |
128,000 |
|
December 1945 |
123,000 |
|
January 1970 |
118,000 |
|
January 1990 |
113,000 |
|
December 1962 |
113,000 |
|
November 1988 |
111,000 |
|
November 1973 |
106,000 |
|
December 1977 |
102,000 |
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Table 25. Peak flows on the Smith River near Crescent City, Del Norte County, California, from 1932 to 1994. Flood stage is about 116,000 cfs. (US Army Corps of Engineers 1971a, USGS 1997) |
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Date of peak |
Discharge (cfs) |
Date of peak |
Discharge (cfs) |
|
|
March 18, 1932 |
61,700 |
November 8, 1963 |
89,200 |
|
|
January 2, 1933 |
51,500 |
December 22, 1964 |
228,000 |
|
|
January 14, 1934 |
33,100 |
January 6, 1966 |
145,000 |
|
|
November 1, 1934 |
33,900 |
January 28, 1967 |
87,800 |
|
|
January 14, 1936 |
55,500 |
February 23, 1968 |
77,800 |
|
|
April 13, 1937 |
70,100 |
February 13, 1969 |
69,400 |
|
|
December 11, 1937 |
78,900 |
January 23, 1970 |
118,000 |
|
|
March 12, 1939 |
41,800 |
January 16, 1971 |
128,000 |
|
|
February 28, 1940 |
37,200 |
January 22, 1972 |
182,000 |
|
|
December 20, 1940 |
44,100 |
December 22, 1972 |
49,800 |
|
|
December 18, 1941 |
62,400 |
November 15, 1973 |
106,000 |
|
|
December 31, 1942 |
91,400 |
March 18, 1975 |
129,000 |
|
|
November 4, 1943 |
40,600 |
February 26, 1976 |
45,400 |
|
|
February 8, 1945 |
56,500 |
September 28, 1976 |
15,800 |
|
|
December 28, 1945 |
123,000 |
December 14, 1977 |
102,000 |
|
|
November 18, 1946 |
50,000 |
January 11, 1979 |
80,300 |
|
|
January 6, 1948 |
83,100 |
November 24, 1979 |
76,500 |
|
|
February 22, 1949 |
48,800 |
December 2, 1980 |
74,800 |
|
|
January 18, 1950 |
91,400 |
December 19, 1981 |
89,600 |
|
|
October 29, 1950 |
152,000 |
March 30, 1983 |
88,400 |
|
|
February 1, 1952 |
61,500 |
February 13, 1984 |
72,500 |
|
|
January 18, 1953 |
139,000 |
November 12, 1984 |
55,700 |
|
|
November 23, 1953 |
141,000 |
February 22, 1986 |
96,800 |
|
|
December 31, 1954 |
70,200 |
February 2, 1987 |
42,400 |
|
|
December 22, 1955 |
165,000 |
December 10, 1987 |
76,900 |
|
|
February 26, 1957 |
67,100 |
November 12,1988 |
111,000 |
|
|
January 29, 1958 |
94,300 |
January 8, 1990 |
113,000 |
|
|
January 12, 1959 |
90,400 |
March 4, 1991 |
52,700 |
|
|
February 8, 1960 |
74,300 |
April 16, 1992 |
31,700 |
|
|
November 24, 1960 |
69,200 |
January 20, 1993 |
76,400 |
|
|
November 23, 1961 |
71,800 |
December 8, 1993 |
37,000 |
|
|
December 2, 1962 |
113,000 |
January 1997 |
Not available |
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The most famous peak flows occurred in 1955 and 1964. The ‘55 flood occurred on December 22, 1955. The flow at the Highway 101 bridge was estimated at 165,000 cubic feet per second. About 7,600 acres near the lower Smith River were inundated (US Corps of Engineers 1971).
In late December of 1964, the most severe flood since European-American settlement occurred when a warm moist air mass collided with cold air over the coast ranges. In nine days, thirty four inches of rain were recorded at Idlewild Maintenance Station in the upper Middle Fork area (California Department of Water Resources 1970). On December 22, 1964, stream flow peaked at about 250,000 cubic feet per second at the Highway 101 bridge. Non-damaging capacity at this location is 80,000 cubic feet per second (California Department of Water Resources 1970). About 9,300 acres of agricultural lands were flooded. The 1955 and 1964 floods triggered numerous landslides, including a forty acre slide in the South Siskiyou Fork basin (California Department of Water Resources 1970). Another high flow occurred in 1972 although this flood did not achieve notoriety.
The lowest recorded flows at the main gauging station on the lower Smith River were 160 cubic feet per second on October 25,1964 and 168 cubic feet per second on October 31, 1931. From 1932 to 1959, the discharge was greater than or equal to 200 cubic feet per second 98.5% of the time (California Department of Water Resources 1970).
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