Laboratory Notes: Groundwater (PDF)

GROUNDWATER! 1 Water: In all its Earthly Forms As previously mentioned: Oceans hold 96.5% of Earth’s water. Rest of water exists as: ✓ Freshwater in rivers and lakes ✓ Frozen water in glaciers and ice caps ✓ Soil moisture and GROUNDWATER AQUIFERS ✓ WATER VAPOR in ATMOSPHERE...

GROUNDWATER! 1 Water: In all its Earthly Forms As previously mentioned: Oceans hold 96.5% of Earth’s water. Rest of water exists as: ✓ Freshwater in rivers and lakes ✓ Frozen water in glaciers and ice caps ✓ Soil moisture and GROUNDWATER AQUIFERS ✓ WATER VAPOR in ATMOSPHERE While the estimates in the above figure are slightly different, we can still clearly see that a large majority of Earth’s water is found in the oceans. 2 Water: In all its Earthly Forms FRESHWATER: water containing less than 1,000 milligrams per liter of dissolved solids, most often salt. Less than 3% of Earth’s water is FRESHWATER. Of that 3%: > 68% found in glaciers/ice caps > 30% found in GROUNDWATER 0.3% found in SURFACE WATER! Let’s take a closer look at an often Caniapiscau River in northern Quebec. overlooked and incredibly important source of freshwater: Groundwater is not as spectacular as this beautiful river, but it is still essential to life on Earth. GROUNDWATER! 3 Water: Groundwater In discussing SOIL, we mentioned that soil particles vary in size. PORE SPACE is the space that exists between soil particles PORE SIZE: size of spaces that exist between SOIL PARTICLES. PORE SIZE IN: GRAVEL > SAND > SILT > CLAY When all PORE SPACES (i.e., the entire PORE VOLUME) filled with water, SOIL is SATURATED. Water found in these SATURATED PORE SPACES is what we refer to as GROUNDWATER. SATURATION of soil particles. 4 Water: Groundwater GROUNDWATER: Water that exists underground in SATURATED ZONES (i.e., areas where soil PORE SPACES are SATURATED/COMPLETELY FILLED with water). UNSATURATED ZONES lie above SATURATED ZONES. In UNSATURATED ZONES, PORE SPACES are filled with water and air. Upper surface of the SATURATED ZONE (i.e., boundary between SATURATED ZONE and UNSATURATED ZONE) is referred to as the WATER TABLE. 5 Water: Groundwater As we can see, GROUNDWATER does NOT form underground rivers. It simply fills PORES (and FRACTURES) in underground materials. You can compare GROUNDWATER to water filling a sponge in your kitchen. AQUIFER: An underground layer of water SATURATED porous rock, rock fractures and/or UNCONSOLIDATED Old-fashioned well for collecting groundwater. materials (e.g., gravel, sand, silt, clay). AQUIFER (Definition 2): Underground formation of permeable rock or loose materials capable of producing useful quantities of water for consumption. Around the world, endless wells pump water out of GROUNDWATER AQUIFERS for a variety of uses. A very large proportion of GROUNDWATER is used in Modern well pumping groundwater. agriculture to water crops and livestock. 6 Water: Groundwater GROUNDWATER can move at different speeds (generally very slowly) depending on PORE SIZES and how well connected PORES and fractures are. Where does GROUNDWATER come from? A fraction of PRECIPITATION (i.e., rain, snow) that falls to Earth seeps its way down into ground, ultimately reaching Precipitation recharges the WATER TABLE, thus joining GROUNDWATER GROUNDWATER AQUIFERS. AQUIFER. Water can stay in AQUIFERS for 1000s of years!!! Surface water (e.g., river or lake water) can also flow down into AQUIFERS through rock fractures/sediment below it. We call adding new water to AQUIFERS the Surface water recharges RECHARGING of AQUIFERS. GROUNDWATER AQUIFERS. 7 Water: Groundwater Fun Facts: A GROUNDWATER scientist is known as a HYDROGEOLOGIST. GROUNDWATER AQUIFERS come in many different sizes, from a few thousand square meters to thousands of square kilometers! GROUNDWATER AQUIFERS can also be just a few meters thick to 100’s of meters thick from top to bottom. Principle GROUNDWATER AQUIFERS in WATER TABLE (and therefore groundwater AQUIFER) may Saudi Arabia. be very deep or shallow depending on location. Usually, GROUNDWATER is found within 100 m of Earth’s surface. However, not always! 8 Water: Groundwater Fun Facts: World’s larger GROUNDWATER AQUIFER: Great Artesian Basin in Australia! Great Artesian Basin covers 1.7 million square kilometers!!! Its GROUNDWATER can be as deep as 3 km below Earth’s Great Artesian Basin covers 1.7 million surface! square kilometers!!! In other areas – it rises to the surface!!! SPRING: Any place where GROUNDWATER flows out onto Earth’s surface! A SPRING receiving water from the Great Artesian Basin. 9 Water: Groundwater Fun Facts: At some locations, ground level (Earth’s surface) may be LOWER than WATER TABLE! At such locations, GROUNDWATER flows out onto surface, thus becoming SURFACE WATER. Once again: SPRING: Any place where GROUNDWATER flows out onto A natural SPRING fed by GROUNDWATER. Earth’s surface! Natural SPRING water in bottles. 10 Water: Groundwater Fun Facts: In Canada, about 30.3% of the population (or 8.9 million people) depends on GROUNDWATER as their source of drinking water/source of water for domestic use. Two-thirds (66%) of people that depend on GROUNDWATER live in RURAL AREAS (i.e., not in the city). Percentage of people dependent on GROUNDWATER varies across the country. Prince Edward Island depends on GROUNDWATER (found in sandstone) for its ENTIRE WATER SUPPLY! Over 60% of New Brunswick’s population also depends on GROUNDWATER. 11 Water: Groundwater Fun Facts: Across Canada, different areas use groundwater for different purposes. Aside from domestic use/human consumption, groundwater can also be used in agriculture and industry. In Alberta, Saskatchewan and Manitoba, primary use of GROUNDWATER is AGRICULTURE. In Quebec: primary use of GROUNDWATER is INDUSTRY. South of the border, in USA, 38% of people rely on GROUNDWATER for drinking water. In USA, about 200 BILLION litres of GROUNDWATER are used for AGRICULTURE each day!!! 12 Water: Groundwater Not So Fun Facts: Like SURFACE WATER and SEAWATER, GROUND WATER can be polluted/contaminated. ✓ Polluting sources include (but are not limited to): ✓ gasoline leakage from storage tanks Landfills can contaminate GROUNDWATER. ✓ chemical leakage from landfills ✓ chemical leakage from industrial waste ✓ pesticides (i.e., insecticides, herbicides, fungicides) ✓ manure and biological waste (can cause bacterial contamination). Pesticides can contaminate GROUNDWATER. 13 Thank you for listening!!! 14