Groundwater Protection

What is groundwater?

Groundwater is found underground in aquifers, which are formations of rocks, sands and gravels that hold large quantities of water. Groundwater feeds springs, creeks, rivers, lakes and wetlands, and seeps into oceans. It is fed by water from rain or melting snow entering the ground, or from nearby rivers.

Why is groundwater important?

Almost all liquid freshwater in the world is groundwater. Life would not be possible without groundwater.  

In Chilliwack, our municipal drinking water supply comes from groundwater in the Sardis-Vedder Aquifer, a natural underground water source that flows, like the Vedder River, from the mountains to the Fraser in the north. This groundwater supply is fed mainly from the Vedder River, as well as from rain and snow soaking into the ground. The groundwater is brought to the surface by pumps and wells, for use by Chilliwack residents and businesses. Many rural properties in Chilliwack also rely on private groundwater wells for domestic use and agricultural water supplies.

Groundwater is also critically important to the healthy functioning of ecosystems, such as creeks, wetlands and rivers. Several salmon-bearing streams in Chilliwack, including Atchelitz, Luckakuck and Chilliwack Creeks, are fed by the Sardis-Vedder Aquifer. It is important to minimize how much water we use to ensure that the aquifer can continue to supply essential water to these creeks.

It is also very important to protect groundwater from contamination because if it becomes polluted, removing pollutants to make the water usable again is often a long and difficult process. This increases the cost of processing groundwater, and sometimes even prevents its use.

Exploring, protecting and sustainably using groundwater is central to adapting to climate change and meeting the needs of a growing population.

What can we do to protect our groundwater?

Groundwater has always been critically important but not fully recognized. We must protect groundwater from pollution and use it sustainably, balancing the needs of people and the planet. Visit these webpages for more information on protecting our groundwater:

- Water Conservation

- A Resident's Guide

- Ground Water Legislation

- Groundwater Protection Plan

- Pesticide Users

- Private Well Owners

- Septic System Users

The Sardis-Vedder Aquifer

Due to the permeable nature of the soils overlaying the aquifer, contaminant migration into this groundwater resource is a concern. You can assist the community by taking measures to prevent chemical and waste spills by ensuring that all hazardous materials are transported, stored, and disposed of correctly, and by working with other members of the community to minimize activities that pose a risk to the quality of our groundwater resources. 

Where is the Sardis-Vedder Aquifer?

The Sardis-Vedder Aquifer lies immediately north of the Vedder River in Sardis and extends north to the No. 1 Highway. It is bounded on the west by the City’s border with Abbotsford and on the east by Prest Road. The location of the aquifer is shown in the adjacent figure. The vulnerability of the areas is indicated by colour coding, red being the most vulnerable area followed by pink then green. (ref: Evaluating Methods of Aquifer Vulnerability Mapping for the Prevention of Groundwater Contamination in BC by K. Ronneseth, M.Wei and M. Gallow of MOE, Dec 1995)

How could the Sardis-Vedder Aquifer become contaminated?

Aquifers are composed of permeable layers of rock, sand, or gravel that enable surface waters, including streams, rivers and precipitation, to percolate into the ground and recharge groundwater resources.

The Sardis-Vedder Aquifer is particularly vulnerable to contamination for several reasons. First, the upper layer of groundwater, the water table, lies only a shallow five to ten metres below the ground’s surface. This is significant, as chemicals or waste materials must travel only a short distance through the soil to impact groundwater quality. Second, the boundary layer of soil protecting groundwater from the upper surface is coarse-grained and consequently extremely permeable. Rainfall quickly seeps through the pores of the coarse soil, carrying contaminants from the surface to the aquifer below. As Chilliwack receives high rainfall, particularly during winter months, preventing the ingress of contaminants due to surface spills is essential.  

It should be noted that the City’s wells pump water from a much deeper zone and water is pumped from a depth of 30 to 40 metres below the ground where the volume and quality of the groundwater is very high.