Our freshwater must be protected

What would we do without good groundwater? Our use of it in our homes, commerce and industry is significant.

In Nova Scotia, over 45 percent of the population relies on groundwater for its domestic and industrial water needs. That number is 100 percent in Prince Edward Island, and nearly two thirds of New Brunswick uses groundwater to meet its potable and industrial water needs.

Groundwater is used, either wholly of partially, by about 92 of 345 municipalities in the region (that number is growing steadily) and by nearly all of the rural population. Its quality and safety cannot be taken for granted.

The endless circulation of water between ocean, atmosphere and land is called the "hydrologic cycle". Inflow to the hydrologic system arrives as rainfall or snowmelt. Outflow takes place as streamflow (runoff), as baseflow (groundwater flow into streams) and as evapotranspiration, a combination of evaporation from open water bodies, soil surfaces and plants.



Water is delivered to streams both on the surface -- as overland flow to tributary channels and by surface flow – as interflow and baseflow, which contributes 30 to 80 percent of the water in our rivers and lakes.

Contrary to many beliefs, groundwater does not flow in underground channels. It flow through complex pathways: between soil particles and through small pores and small fractures in bedrock – much like water through a sponge.

It is clear that a watershed must be viewed as a combination of both surface drainage and groundwater drainage. However, most watershed studies to date have considered only the surface water.

Groundwater is vitally important to the hydrosphere. If one removes the 94 percent of the earth's salt water that rests in the oceans and seas, then groundwater accounts for 96 percent of the useable fresh water on the earth.

Groundwater pollution can last a long time. Pollutants often degrade quickly when they are exposed to sunlight and air. But cold temperatures, darkness and low oxygen levels can cause these same pollutants to persist in the subsurface.

Clays and other earth materials provide some buffering against groundwater pollution, but nature can only do so much.

Groundwater is out of view, so there can be long time delays before pollution is detected. These delays can further compound the problem by allowing pollutants to spread and affect even larger areas of watersheds and the environment.

Since groundwater contributes 30 to 80 percent of the water in our rivers and lakes, polluted groundwater can also pollute surface water. So now is the time to take action to preserve the earth's freshwater.

All too often, the action taken to protect groundwater involves nothing more than "placing a fence around the wellhead", or placing a clay capping layer over a landfill, while leachate can emanate from the site underground. Very little is done to protect groundwater at its source.

Proper groundwater management requires that we do total watershed management.

Few studies have been done of whole watersheds, and the study of groundwater is complex. However, society is starting to realize groundwater's value and importance to the environment. There is a long way to go but a foundation is being set for the next generations to continue to search for better understanding of what may be our most important and valuable natural resource – groundwater.

Original article written by Rick Gagné and published in the Halifax Mail Star, 1994.