Page 253 - The City and Guilds Textbook: Plumbing Book 1 for the Level 3 Apprenticeship (9189), Level 2 Technical Certificate (8202) and Level 2 Diploma (6035)

Chapter 5 Cold water systems

Source of water Description Properties of water from this source
Spring A naturally occurring flow of water from the Earth’s The purity of the water is highly dependent on the
surface. distance it has travelled from the source.
River A large natural flow of water, usually starting as a Usually poor quality due to industrial pollution. The
small stream on high ground, which enlarges with cost of treatment is high.
distance travelled. Usually terminates at the sea and
can be tidal, such as the River Avon.
Canals Most canals are a product of the Industrial Revolution Very poor quality, generally used only for industrial
and for many years fell into dereliction. Many, though, purposes and irrigation.
have been cleaned and re-opened, and are now sites
of natural beauty.
Aquifers Naturally occurring water-bearing strata, often Very high quality, but prone to contamination by
deep beneath the Earth’s surface. Mostly consist of nitrates from farming.
permeable rock, such as sandstone, gravel silt or clay,
which soaks up water like a sponge (see Figure 5.4).
Artesian wells and Water that rises from underground water-bearing rock Usually very good quality as the water is filtered
springs layers under its own pressure, but only if the well head naturally through layers of rock.
is below the level of the water table (see Figure 5.5).
Boreholes Man-made wells that are drilled directly to a below- Very high-quality water that, in most cases, is
groundwater source and the water extracted for use if cleaner than the water undertaker’s water main.
connection to a water main is extremely difficult. Filtering and chlorination are not necessary,
although the quality should be monitored.

Lake Deep well Land spring Unconfined aquifer Shallow well

Impervious strata
INDUSTRY TIP
Pervious strata
The Environment Agency is
Confined aquifer
the overseeing authority for
Impervious strata all watercourses in the UK.
It samples about 7000 river
p Figure 5.4 Deep and shallow wells
and canal sites 12 times a
year to test their chemistry
Artesian spring Artesian well and nutrients so it can
Impervious strata
see whether there are any
Plane of saturation
pollutants and whether it
needs to target areas for
improvement.

Impervious strata Water-bearing strata

p Figure 5.5 Artesian wells and springs

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