What is a Spring?
A spring is a place where water naturally flows freely from the ground or where it lies in pools that are continually replenished from below. A seep is a variety of spring in which the water comes, not from any definite opening, but through the pores of the ground over a considerable area. Many marshes and swamps are actually seeps on a large scale. Large ponds or lakes that are supplied with water through openings in their beds are called spring-fed lakes. Artesian wells are not regarded as springs since they require an artificial opening in order to access the water.
Springs are not limited to the Earth's surface. Recently, scientists have discovered hot springs at depths of up to 2.5 kilometres in the oceans, generally along mid-ocean rifts. The super-heated water coming from these springs is rich in minerals and sulphur, which results in unique ecosystems where unusual and exotic sea life seems to thrive.
How a Spring Works
Conceptually springs consists of:
- A Recharge Area where water enters the subsurface
- An Aquifer or set of aquifers through which the water flows
- A Discharge Point where water emerges as a spring.
An aquifer is an underground layer of permeable rock or sand that collects, holds, and conducts water. The materials act like underground sponges allowing water to flow very slowly through it, filtering out contaminates such as bacteria. Water in the aquifer is called groundwater. Many aquifers are like reservoirs because they store water useful to humans and aquatic ecosystems. Aquifers vary in size, from narrow to wide, and may be hundreds of feet thick. They may span a small area or may stretch across thousands of square miles.
Most of the water that emerges at springs is meteoric in nature: that is, it originally fell as rain or snow on the surface of the Earth. At hot springs near active volcanoes, some of the water may have originated from magma, molten rock that also contains dissolved substances such as water. As magma cools and crystallizes in the Earth's crust, it releases much of this water. Spring water also can be ancient sea water, although it usually is diluted with meteoric water.
Types of Springs
Gravity springs usually start with a recharge area. This pool or mass of water continually saturates the ground. The water infiltrates the ground and continues to penetrate downward until it encounters an area of lower permeability where it is blocked (for example, by bedrock) or cannot travel down as fast as it is supplied at the surface. As a result, the water spreads laterally until it intersects the land surface where erosion has lowered the topography to the water's level (for example, on the side of a road-cut). In this situation, the aquifer is unconfined; movement of water is due mostly to the force of gravity.
Gravity Overflow Spring
(Source: SMET & WIJK (2002))
Contact Spring
(Source: Kansas Geological Survey, Public Information Circular (PIC) 11)
Artesian springs occur when the aquifer is trapped under a layer of impermeable rock or soil. This result in the groundwater becoming pressurized above atmospheric pressure. This pressure forces water upwards through any cracks or openings in the overlying impermeable layer.
Artesian Spring
(Source: SMET & WIJK (2002))
Tubular and Thermal springs are sometimes counted as separate types of springs. However, these can be topics for another Earthcache.
Flow Rate
Recharge is the rate and volume at which rainwater seeps through recharge areas and into an aquifer. Recharge and discharge can be subject to seasonal fluctuations. For example, an aquifer that is highly reliant on seasonal rainfall or snow-melt to feed it may not be able to sustain a spring all year around. There would still be water in the aquifer, but not enough to sustain the outflow of the spring.
Discharge from springs depends on many factors, including the size of the caverns within the rocks, the water pressure in the aquifer, the size of the spring basin, and the amount of rainfall. Human activities also can influence the volume of water that discharges from a spring - ground-water withdrawals in an area can reduce the pressure in an aquifer, causing water levels in the aquifer system to drop and ultimately decreasing the flow from the spring.
If recharge rates to the groundwater system are low, and the distances traveled by the water are great, then the age of spring water can many (even hundreds of) years old. In general, when water age is old, variations in the flow of water from the spring will be small.
The magnitude of a spring is based upon its flow rate as follows:
| Magnitude |
Flow |
| 1st |
2800 L/s |
| 2nd |
280 to 2800 L/s |
| 3rd |
28 to 280 L/s |
| 4th |
6.3 to 28 L/s |
| 5th |
0.63 to 6.3 L/s |
| 6th |
63 to 630 mL/s |
| 7th |
8 to 63 mL/s |
| 8th |
Less than 8 mL/s |
| 0 |
No flow |
(Source: Wikipedia)
Water Quality
An unconfined aquifer is surrounded on top by a highly permeable layer, where a lot of rainwater seeps through the soil layer, recharging the aquifer at high rates. A confined aquifer, has a limited permeable layer on top, perhaps porous rock below the saturated soil zone, resulting is lowered recharge rates, but in theory cleaner, more naturally filtered water.
The quality of the water in the local ground-water system will generally determine the quality of spring water. The quality of water discharged by springs can vary greatly because of factors such as the type of rocks with which the water is in contact and the rate of flow and the length of the flow path through the aquifer - flow rate and the length of the flow path affects the amount of time the water is in contact with the rock, and thus, the amount of minerals that the water can dissolve. Because not all aquifers and mineral deposits are the same, the water from a particular mineral spring may have its own unique taste. The quality of spring water can also can be affected by the mixing of freshwater with pockets of ancient seawater in the aquifer or with modern seawater along an ocean coast.
The temperature of spring water is related to the amount and rate of groundwater flow. As depth below the Earth's surface increases, temperature increases. As a result, deep circulating groundwater can be warmed. If groundwater velocities are low and the springs are small, most of the heat will be conducted though the rocks and the water will remain cold. If the springs are large, the spring water also will be cold because the volume of water is too great to be adequately warmed. The warmest springs occur when discharges are moderately large, and often are found in regions where the subsurface is unusually warm, such as volcanically active areas.
The Wakefield Spring
The Wakefield Spring is owned and maintained by The Municipality of La Pêche. According to Natural Resources Canada experts, the water feeding this spring appears to come from the hills in the upper watershed area, to the east and south of the spring, and from the sand and gravel pit located on either side of Route 105, near Rockhurst Road.
A 2010 citizen's study into who uses the spring found that over 3,000 residents stop by and fill up year round; the numbers increase in summer, when at least 2,000 cottagers stock up on their way to their weekend getaways. A smaller percentage take the water to Ottawa to use for wine and beer making, and some restaurateurs serve it to their customers.
Safety and Testing
The municipality ensures the spring's ongoing safety and makes it freely accessible to the public. Provincial regulation requires the municipality to test the water according to an established schedule and submit the results regularly to the MDDELCC (Ministère du Développement durable, de l'Environnement et des Parcs). This includes bacteriological testing every 2 weeks and turbidity measured monthly. Nitrates and nitrites are tested every three months and barium, chrome, arsenic, mercury and cyanide are tested yearly. Virological analyses as well as testing for chloride, perchlorate and formaldehyde have also been added to the water quality monitoring schedule.
Your Mission
Go to the posted coordinates, bringing with you a large container of known volume and a timing device. If you don't have a container with you, watch someone else fill up. Answer the following questions based on the information above and what you observe at the site:
- What type of spring is this and why?
- Describe the appearance, temperature, and smell. What does this tell you about the spring's aquifer?
- Time how long it takes to fill the container, then calculate the total flow rate of the spring. What is the total flow rate in litres/second (L/s) (both taps) and what is the spring's magnitude?
- What impact(s) might result from the removal of sand and gravel from the nearby Rockhurst Road sandpit?
E-mail your answers to me. You don't have to wait to log your visit. If your answers are not correct or you forget to send them, I will let you know.
Parking is available on the side of the road.