Meet the Mayor
October 10, 2013
Most of you have heard of the land slide that temporarily blocked the Pine River just west of Hasler Flats last week. Tons of earth simply cut loose and slipped into the river taking with it hundreds of tall, straight, and beautiful aspen trees along with the understory. It’s an awesome thing to see what was supposed to be several acres of solid earth, having removed itself, simply park in a new location.
The day after the slide I visited the site with CAO Doug Fleming, Manager of Public Works Operations Paul Gordon, and MEP Coordinator Leo Sabulsky. We wanted a first-hand look at the potential for long-term effects on the District water supply. Because the water again was flowing clean and unrestricted, we were reassured that the immediate crisis was past and that in the long term the slide would not affect the water supply seriously.
Of course we are not even amateurs in assessing slide impacts and long-term implications. At the site when we visited were two engineers from MoE in Prince George already on their second day of testing. They were using an instrument that I had not encountered at any time in my previous life. A rather simple device, it inserts into the earth on the end of a shaft a four-blade tip about six inches in diameter. In this case the technicians drove it to a depth of six meters. On the top of the shaft a meter is mounted to read the tension on the blades. The degree of tension will allow the technicians to assess the stability of the earth on which we were standing a few meters back from the edge of the slide.
As an untutored observer, I saw some conditions of interest. The soil consists of various layers of sand, silt, and clay. It appeared to me that there was an impervious layer at the bottom of the slip which allowed the soils above it to become saturated with water. When the resistance to slipping was exceeded by the weight of the water-saturated soil above, it simply let go and moved south to block the river.
Chetwynd’s Utilities Services Coordinator, Al Tricker, responded by promptly shutting down the pumps to avoid contamination by the river-born silt. Once the river breached the slide a wave of muddy-brown silty water moved downstream. At this time of year the river is flowing more slowly than in the spring and it took about 36 hours for the wave to pass the pumping station and the river to clear.
Chetwynd has several defenses against primary water contamination. In the first place, good planning has allowed the District to prepare for emergencies and District employees are alert and quick to respond. Secondly, our settling ponds hold several weeks’ supply, and finally, the wells can be turned on when necessary.
We are pleased and reassured with the way everyone responded to this inconvenience so that it did not become an emergency.
Merlin Nichols, Mayor