Natural springs can be found in all shapes and sizes, all over the world. From a small trickle of water filtering through leaves on a forest floor to the spring fed Lake Itasca in Minnesota - the source of the mighty Mississippi river. Springs typically occur along hillsides, low-lying areas, or at the base of slopes.
Technically, a spring is the result of an aquifer being filled to the point that the water spills out above ground. Springs may be classified according to the geologic formation from which they obtain their water, such as limestone springs or lava-rock springs; or according to the amount of water they discharge, or according to the temperature of the water, or by the forces causing the spring-gravity or artesian flow.
The amount of water that flows 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. Springs range in size from intermittent seeps, which flow only after much rain, to huge pools flowing hundreds of millions of gallons daily. Small springs are found in many places. Springs may be formed in any sort of rock.
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.
Springs are not limited to the Earth's surface, though. Recently, scientists have discovered hot springs at depths of up to 8200 feet in the oceans, generally along mid-ocean rifts (spreading ridges). The hot water (over 572 degrees Fahrenheit) coming from these springs is rich in minerals and sulfur, which results in a unique ecosystem where unusual and exotic sea life seems to thrive.
Why Should You Measure The TDS Level In Your Water?
The EPA Secondary Regulations advise a maximum contamination level (MCL) of 500mg/liter (500 parts per million (ppm)) for TDS (Total Dissolved Solids). Numerous water supplies exceed this level. When TDS levels exceed 1000mg/L it is generally considered unfit for human consumption. A high level of TDS is an indicator of potential concerns, and warrants further investigation. Most often, high levels of TDS are caused by the presence of potassium, chlorides and sodium. These ions have little or no short-term effects, but toxic ions (lead arsenic, cadmium, nitrate and others) may also be dissolved in the water. Learn more about contaminants and the maximum contaminent levels at EPA.gov.
According to the WHO, if chlorine is used as a method of water treatment, then it's important to anylise the residual chlorine level daily.
Spring Water Is Not Always Clear
Water from some springs may be "tea-colored." In southwestern Colorado, red iron coloring and metals enrichment are caused by groundwater coming in contact with naturally occurring minerals present as a result of ancient volcanic activity in the area.
In Florida, many surface waters contain natural tannic acids from organic material in subsurface rocks, and the color from these streams can appear in springs.
If surface water enters an aquifer near a spring, the water can move quickly through the aquifer and discharge at the spring vent. The discharge of highly colored water from springs can indicate that water is flowing quickly through large channels within the aquifer without being filtered through the soil.
Is Spring Water Always Fit To Drink?
Should you always feel confident about filling your canteen with cool and refreshing spring water? No, you should be cautious.The quality of water discharged by springs can vary greatly according to the quality of the water that recharges the aquifer and the type of rocks the groundwater contact.
The rate of flow and the length of the flowpath through the aquifer affects the amount of time the water is in contact with the rock, and thus, the amount of minerals that the water can dissolve. The quality of the water also can be affected by freshwater mixing with pockets of ancient seawater in the aquifer or with modern seawater along an ocean coast.
Some springs are only crudely filtered in the rock(this is especially common in areas of limestone). If water from the spring becomes muddy or is discolored shortly after a rainstorm, it is evidence that surface
runoff is readily entering the spring. This may mean the spring is contaminated with pollutants from sources upslope from the spring’s emergence.
If underground long enough, lack of sunlight causes most algae and water plants to die. However, microbes, viruses, and bacteria do not die just from being underground, nor are any agricultural or industrial pollutants removed.
When in lower elevations(especially lower than 7000 feet), use caution when drinking water from springs(or any backcountry water!). Some concentrated springs emerge in valleys or lowland areas. A spring that forms in a low area may be very difficult to safeguard from bacterial contamination since surface water will tend to flow toward these valleys. For this reason, it is critical that water collected from these areas is regularly tested and, if necessary, receives disinfection treatment.
When considering using a spring as your source of drinking water, it is important to ensure that the rate of flow is reliable during all seasons of the year. Spring flow that fluctuates greatly throughout the year is an indication that the source is unreliable or may have the potential for contamination. It may be possible to learn about historical spring flow from the previous owner or a neighbor.
Learn how you can test the flow rate of a spring here.
Credit For Content:
USGS.gov - US Geological Survey
Penn State College of Agricultural Sciences Extension
WHO - World Health Organization