Whenever we start a new excavating or retaining wall project, there is always the question in our minds “What are we going to dig up?”. Usually just dirt and rocks. And of course, we always find out where the gas and hydro lines are before starting any new digging on your property, so there won't be any surprises there.
In our latest retaining wall job in North Vancouver, in the foothills of Grouse Mountain, we discovered a new underground friend – groundwater. We were excavating away, and then were suddenly hit with a gush of water.
Groundwater can be found virtually anywhere. The area where the water fills up and pools is called a water table. The water table can be very deep down, hundreds of feet where it won’t cause any problems for an excavator, or it can be just a few feet below the surface, where a bit of digging will find it quickly. It’s recharged by rain and snow melt, which makes the areas in the Lower Mainland at the foot of mountains, such as North and West Vancouver, a hot bed of groundwater activity.
So what does severe groundwater or a high water table mean for your retaining wall or excavation project? Not to worry, we can still get the job done. Just a few things to keep in mind…
- Depending on the amount of groundwater, it may delay the schedule of your project, as it impedes the efficiency of drainage installation and can extend build time.
- It could also affect the estimate we gave you, especially if we have to spend a considerable amount of time dealing with the groundwater. Major groundwater also requires more filling materials than for a regular retaining wall job.
- It will not affect the strength and stability of the retaining wall, and with the pipe we install, you will now have a proper drainage solution in place to divert the water away from your retaining wall and property, so it's actually a good thing in a way.
- If you are using our excavation services, and will have another contractor coming in, you should let them know about the groundwater so that they can prepare their part of the project accordingly.
How to know if you have a groundwater issue? A wet basement, or one that floods often could be an indication. You can also have your soil tested by an engineer if you are concerned. And if you want to learn more about draining solutions if you do have a groundwater problem, check out this article.