As was evident in the map, groundwater is the only source of
water for many people. In many states, all of the rural citizens
use groundwater for their water supply. In some states,
groundwater is used as the public supply for most of the
population.
The construction of a gravel pack involves the removal of the aquifer material from the area immediately surrounding the planned position of the well screen and the substitution of well-sorted, well-rounded gravel or coarse sand in its place. The purpose of this is increased permeability around the well and increased performance of the well itself.
In this method, an auger stem (shaped like a big screw) is turned
by hand or rotary drive head. When the blades of the auger are full,
the stem is pulled out of the hole and cleared of material. As the
depth of the hole increases, segments of auger stem are added.
A bailer is a long bucket with a valve on the bottom
and a bail on top. It is lowered down into the hole, filled with
water and withdrawn. By repeating this a number of times and by
counting the number of buckets, a driller can get a good idea as to
how much the well will produce.
In naturally developed wells, there is commonly an annular space
around the screen. Filling this space with clean, coarse sand or a sand-gravel
mixture will stabilize the formation around the screen before
development. Proper development is more easily carried out when caving is avoided
in this way.
Stabilizer material is not of any special grading and should be about
the same size or slightly coarser than the formation material.
Screen slots should be selected as if there were no formation stabilizer
present.
Intermittent uses are those uses which normally last for 5
minutes or less. All general-use home applications are of this type.
Seldom do any of these uses extend for more than five minutes or, at
most, for 10 minutes. They include kitchen, bathroom, and laundry uses.
In areas that have low rainfall, groundwater is of special
importance because surface water may be virtually
nonexistent. If conditions are particularly arid, then
groundwater supplies will also suffer due to the lack of
replenishment
In this common method,
excavated material is collected in a cylindrical bucket
having auger-type cutting blades on the bottom. When the
bucket is full, it is pulled out of the hole,
emptied, and reinserted into the hole to continue the process.
Water is considered safe to drink if it is free from disease-causing organisms and contains no chemicals in concentrations exceeding primary standards established by the Environmental Protection Agency. Safe water is often referred to as potable.
Sustained uses are those that normally extend for more than 10 minutes. These include lawn or garden watering, livestock watering with either automatic or non-automatic waterers, and hose use for cleaning floors, cars, or tractors.
Large amounts of water can be saved in the home by taking simple
water saving measures. Water use can be cut to an amazing 89
percent in some cases. Some water-saving fixtures can be found
as standard options on appliances that use water. The following
tables describe how water can be saved in numerical form. About
70 percent of the total water used in the home is for toilet
flushing, laundry, and baths. So, the most significant water
savings can be made in these areas.
The uniformity coefficient is a "ratio of the 60-percentile to the
10-percentile" (Fair, 1965).
It measures how constant the sand particles are.
The lower the value, the more uniform is the grading of the sand.
It is evident from this graph that everyday tasks such as
flushing a toilet consume large amounts of water. There are
ways, however, to reduce these amounts with economy water saving device.