HISTORICAL NEWS SEARCH - Government of British Columbia

idge construction project near Terrace. One unfinished pier in the centre of the river was continually hit by debris,
causing the support poles to tilt. Rebuilding the whole pier could delay the project by six weeks. The new bridge with
16 piers crossing Dudley Little Main and Dudley Little West channels was to replace the old curved one-lane wooden
bridge.
Two slides along the Skeena River and washouts at Mile 43 and 10 mi. (16 km) west of Terrace cut the CNR
line and Highway 16 between Prince Rupert-Terrace. The rail traffic was interrupted until October 17. Another closure
of the CNR line occurred about 30 mi. (48 km) east of Terrace and was expected to be repaired by 6 p.m. on October
16. Washouts also closed down the road between Kitimat-Kitamaat Village and the ones between Terrace-Stewart and
Stewart via Meziadin Lake.
The exceptionally heavy rain caused mudslides, cutting BC Hydro’s main transmission line about 60 mi. (96
km) east of Prince Rupert. A mudslide and a washed-out power pole cut the main power line to Prince Rupert at Mile
51. Power in Prince Rupert was out for five-and-a-half hours. There were also power outages in Terrace and Kitimat
and major transmission problems between Terrace-Prince Rupert.
The Kitimat River level rose 13.6 ft. (4.08 m), causing the “worst flooding since 1966.” On October 15, the
Kitimat River below Hirsch Creek recorded a maximum instantaneous discharge of 2,020 m 3 /s and a maximum daily
discharge of 1,650 m 3 /s (Environment Canada 1991). North of the Kitimat bridge, the north arm of the main dike
collapsed for over 200 ft. (60 m). Dykes erected since the 1966 flood prevented flooding of the Service Centre. Major
gravel movement took place near the Service Centre bridge. Several loads of shot rock were dumped to protect the
Municipal sewage treatment facilities. Radley Park was completely under water. The bridge near the Minette Bay
Marina was taken out. The road into the Kitamaat village was impassable as the bridge just before the village was
flooded. Extensive damage occurred, especially at Hirsch Park. In the Kildala section of Kitimat, basements were
flooded. Roads, including the road to the Alcan Smelter site, were flooded. The Alcan water intake on the Kitimat
River crested at 49 ft. (14.7 m) as compared to 50 ft. (15 m) in 1966. Flooding and bank erosion occurred along the
river. Heavy gravel movements took place and on many smaller tributaries of the Kitimat River erosion and silting
were severe. The silt load was extremely heavy, with visibility down to a “fraction of an inch.” At many points in the
river logjams formed. The most dramatic changes occurred on the steeper gradient tributaries, such as Moore and
Anderson creeks. Flooding and bank erosion took place, on many smaller tributaries of the Kitimat River and erosion
and silting were severe. Logs and debris from a logjam that broke loose above the falls on Anderson Creek lodged
against the bridge on the Alcan Road. After water started backing up over the road, heavy equipment lifted out the
debris. Water backing up from the Kitimat River caused the bridge over Goose Creek on the Eurocan Main Line to
float out.
Similar incidents occurred at a number of other points along the logging road network in the Kitimat Valley.
At the height of the flood, back pressure on the diffuser outlet of the Eurocan Pulp and Paper Company effluent
treatment ponds brought the water level in the outlet chamber to within a few inches of the pond level. An estimated 5
ft. (1.5 m) of gravel built up over the diffuser, causing the installation to fail to function properly. Gravel deposited
behind the rock groyne on the opposite side of the river completely cut off the flow into the side channel. After the
channel became filled with gravel, sand and silt, most of the seepage into the oxbow was cut off, adversely affecting its
rearing capacity. The major logjam near the Crown Zellerbach (CZ) bridge increased in size, diverting more of the
flow to the west side of the river. The build-up of logjams and gravel bars upstream of the third and fourth CZ bridges
(from the highway) diverted nearly the entire Kitimat River. This left little water under the main bridge. Between the
CZ bridge and the 17 Mile bridge many bars changed, drying and/or silting up a number of spawning channels. In
several places on the west side of the river severe erosion occurred. On the upper ends of islands and along both sides
of the river new logjams formed. Upstream of the 17 Mile bridge, major bank erosion took place and many new
logjams formed up to the limits of tree growth.
On Hirsch Creek, gravelbars changed and several logjams formed. Judging by the large amount of debris in
the lower reaches, major changes must have taken place above the canyon. Severe scouring and erosion took place
along Nalabila Creek. A massive logjam formed on Branch 20, approximately 150 yd. (135 m) downstream of the
bridge. The jam, which was at least 150 yd. (135 m) long, effectively blocked the stream to salmon migration. It
forced the stream to spread out along the length of the dam and to meander though the timber with no definite
channels. Much of the stream channel between the Branch 20 bridge and the logjam built up to a higher level than the
surrounding area. It was contained in its present course only by a low “dyke” of silt and small debris deposited during
the flood. It was believed that the stream left the channel and meandered off through the timber. The lower reaches of
Humphrey’s Creek downstream of the highway showed considerable siltation. A large logjam built up about 300 yd.
(270 m) below the canyon. Due to the nature of this stream, the changes were not as apparent as in Nalabila Creek.
Road access to Chist Creek was blocked.
Many minor slumps and slides throughout the logged-off areas accumulatively contributed large quantities of
silt to the stream. Small jams and some localised erosion silting occurred in Cecil and Deception creeks. In the
Wedeene River some small jams formed and some bank erosion took place. Locally, some severe scouring and silting
took place. At the chronic problem areas along the Wedeene Main Line, sloughing of silt and clay was considerable,
adding to the overall silt load of the river. A large mudslide on a tributary of Dahl Creek contributed large quantities
of silt to Dahl Creek, and to some extent to the Little Wedeene River.
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