After the draining of Sumas Lake and construction of the Vedder Canal Dykes in the 1920s, the community finally felt protected from the dangerous forces of the nearby rivers. By that time, there were dykes constructed along most of the Fraser River to protect Chilliwack from flooding. This complacency led citizens to neglect the dykes and they ended up becoming covered in brush and trees. Then, in the winter of 1947 - 1948, high snow accumulations in the mountains combined with an unseasonably cold spring resulted in very little runoff. In May high temperatures and warm rains caused the local water levels to rise at all major drainage basins in the province. Although residents of Agassiz and Rosedale tried to reinforce the neglected dykes, on May 26, 1948, the Agassiz dyke broke when the Fraser River reached 21 feet at the Mission Bridge gauge. Two days later the river had surpassed the 23-foot mark and there was a breach of another dyke, which was repaired shortly after. By the end of the month water levels reached 24.08 feet at the Mission gauge and the Matsqui dyke had collapsed. In early June, there was a break in the dyke protecting Greendale, and the rural community was flooded. Many of the evacuated residents from Greendale escaped to the Cultus Lake area and when they were able to return to their homes, the majority of livestock had perished, gardens were covered in debris, and houses were damaged.
Although there is always mention of the Chilliwack Flood of 1948 within the City's history, it wasn't the first time there had been flooding in the area. In 1875, about a decade after settlers first arrived in the area, the Chilliwack River overflowed her banks followed by the Fraser River the year after. Shortly after, the provincial government appointed a civil engineer to devise a plan to avoid another major flood. But due to political and economic issues at the time, none of the plans developed were carried out. Then came the Big Flood. By 1894, no flood controls were in place other than a dam across the Hope Slough in Rosedale. The water began to rise on May 19th. By the 30th residents were assured the worst had passed since water levels were short of a few inches of the highest flood waters previously recorded in the area. But on June 6th the river reached a new peak at 25.75 feet at the Mission gauge. Most of Chilliwack was under water and local boys provided "ferry" services in their homemade boats to those needing to cross the street. Communication was interrupted for several days, CPR lines were damaged and crops and livestock were lost. By the end of June that year a meeting of settlers was called to talk about dyking options.
Following the two major floods in the Chilliwack area, there were two subsequent lesser Fraser River floods in 1950 and 1972. Although they caused some property damage, because the dykes had been widened and heightened after the flood of 1948, the damage caused was greatly reduced from previous years. Since 1948, the Fraser River dykes surrounding Chilliwack have been upgraded and maintained. The City of Chilliwack continues to carry out dyke upgrades to protect the community from another big flood like the one in 1894. The dykes along the Fraser are made up of silt on the river side and gravel on the land side. Relief wells and dyke drains relieve pressure that builds up.
There are also dykes in place to protect the community from Vedder River floods. In December 1975, during a flood on the Vedder River, water overtopped the bank and caused flooding in the community of Yarrow. This event led to the construction of the setback dykes along both sides of the Vedder River, upstream of the Southern Rail crossing.
The dykes not only serve a practical purpose, they also provide recreational opportunities to fishermen, cyclists and walkers like you.
Gravel is removed from the Vedder River and Canal every two years to maintain the flow capacity of the floodway between the two setback dykes. The gravel removals are planned and monitored by environmental professionals, to protect the salmon and other fish and aquatic species.
To help protect Chilliwack from flooding, each year the City undertakes a set of measures prior to the freshet. They update the Flood Response Plan; they do routine dyke maintenance and inspections; they maintain an up-to-date Emergency Dyke Upgrades Plan, which shows how to handle priority areas for upgrading in an emergency situation; and they also closely monitor the snow pack and runoff forecasts.
Now keep an eye out and an ear open for woodpeckers. The Downy Woodpecker and the Yellow-bellied Sapsucker are the two species of woodpecker most common to the trail area; at very least, you should spot evidence of these woodpeckers carving the trees. As juveniles, Downy Woodpeckers display a red cap. The adult male has a red patch on the back of his head while the female does not. The Yellow-bellied Sapsucker adults are black on the back and have wings with white bars; they have a black head with white lines down the side and a red forehead and crown; a yellow breast and upper belly; a white lower belly and rump; and a black tail with a white central bar. Adult males have a red throat; females have a white throat. We'll have more information about these marvelous birds with future trail updates.