ground water watertable wells springs

1. Presented By:-
Presented To:-
Navodit Bhandari Mr.
Vinod Balmiki
B.Tech, Civil Engg.
5th sem, Roll No:18
Subject:- HYDROLOGY
Topic
Water Table ,Wells ,Springs and their types

2. CONTENT
INTRODUCTION TO WATER TABLE
TYPES OF WATER TABLE
INTRODUCTION TO WELLS
TYPES OF WELLS
INTRODUCTION TO SPRINGS
TYPES OF SPRINGS

3. Introduction
WATER TABLE
The water table is an underground
boundary between the soil surface and the
area where groundwater saturates spaces
between sediments and cracks in rock.

4. Types Of Water Table
Perched Water Table: This is an elevated water table that occurs above the
main water table. It is often found in localized areas where impermeable layers,
such as clay, trap water above them.
Unconfined Water Table: The most common type, the unconfined water table
is free to fluctuate based on precipitation, surface water interactions, and other
factors.
Confined Water Table: In contrast to the unconfined water table, the confined
water table is located beneath impermeable layers, creating a confined aquifer.
The water in this table is often under pressure and may rise above the top of
the aquifer.
Permeable Water Table: This refers to a water table located in permeable or
porous materials like sand or gravel, where water can easily move through the
spaces between particles.
Artisan Water Table: An artisan water table is a confined water table where the
water naturally rises above the ground surface due to pressure in the aquifer.
Shallow Water Table: A water table that is close to the ground surface, typically
within a few meters. Shallow water tables can have implications for
construction and agriculture, as they may influence soil stability and plant
growth.
Deep Water Table: A water table that is located deeper underground, requiring
deeper wells for extraction. Deep water tables are less susceptible to short-term
fluctuations due to weather conditions.

5. INTRODUCTION to WELLS
A well is a deep hole or shaft dug into the ground to access natural resources.
There are water wells, oil wells, gas wells, and more. Wells have been used in
many cultures around the world for over 8,000 years. The first wells were likely
dug by hand or with very simple tools. They provided access to groundwater that
could be brought to the surface. As rain falls, it is absorbed into the soil. This drips
down, providing water to many plants. It continues moving through layers until it
passes the water table. The water table is the line where the soil stops and water
starts. The water stops when it gets to rock that it can't move past. This creates
open spaces where it gathers into underground pools. In fact, over 90% of the
world's freshwater is underground. By digging down into one of these
underground pools, a bucket can be placed in the water and then pulled up with a
rope. Wells provide a reliable source of clean water to many homes, farms, and
some industries. In America, more than 15 million homes have water wells. Of
course, as the ground becomes contaminated, the groundwater can also become
contaminated.

7. TYPES OF WELLS:
1. Dug Wells
:
Dug wells are shallow and they are not the best option for your drinking
water. This type of well poses the highest risk of contamination of the
water supply due to poor protection from surface water. A dug well
usually consists of a large diameter hole that is usually over 2 feet wide,
and it can be constructed by hand or using excavation equipment. The
large-diameter wells are usually constructed using corrugated
galvanized steel or prefabricated concrete tile. Older wells are often
constructed of stone, brick, or wood cribbing and they are very
susceptible to surface-water seepage.

8. 2. Bored Wells:
Bored wells are constructed using a boring
machine and they usually have an average
depth of about 15 m or 50 ft., although some
wells are 30m or 100 ft. deep. The wells that
are usually about 2 feet in diameter are
constructed using an earth auger and
concrete is the most common material used.
As these wells are typically shallow, they are
susceptible to contamination. Apart from the
high risk of contamination, the low water
levels mean that the wells are often the first
to go dry during drought.

9. 3. Driven Point Wells:
The sand-point or driven-point wells are
constructed using assembled lengths of
pipe that are driven into the ground. These
wells are usually small in diameter- about 2
inches or less, and they are less than 50
feet in depth. These types of wells can only
be installed in locations with relatively
loose soils, such as sand and gravel
aquifers. They are driven into the ground or
inserted using high water pressure and
they are often only installed in places with a
shallow water table that contains
little or no stones.

10. 4. Drilled Wells:
Drilled wells often refer to all the other types
of wells, and this includes those that are
constructed using a combination of driving
and jetting. Drilled wells for farm use are
usually 4 to 8 inches in diameter and they
pose a low risk of contamination when
properly constructed. Drilled wells can get
water from bedrock aquifers and
overburden. The overburden wells are
usually composed of sands and gravels and
they include those constructed into the
geological materials that are above bedrock.

11. INTRODUCTION to SPRINGS
Spring, in hydrology, opening at or near the surface of the Earth for the
discharge of water from underground sources. A spring is a natural
discharge point of subterranean water at the surface of the ground or
directly into the bed of a stream, lake, or sea. Water that emerges at the
surface without a perceptible current is called a seep. Wells are holes
excavated to bring water and other underground fluids to the surface.
Water in springs, seeps, and wells generally originates as rainfall that
has soaked into the soil and percolated into underlying rocks. Permeable
rocks (those containing interconnected pore spaces through which
water can migrate), such as limestone and sandstone, store and transmit
water and are called aquifers.

12. TYPES OF SPRINGS:
1. Stratum springs:
A stratum spring is formed when the downward passage of
groundwater in a permeable deposit is hindered by an underlying
impervious layer.

13. 2. Fault springs:
Faulting may also give rise to conditions in which groundwater (at depth)
under hydrostatic pressure (such as in confined aquifers) can move up
along such fault openings to form a spring.

14. 3. Artesian springs:
In this type of spring, impermeable units confine the aquifer. In order
for the water to exit or seep from the reservoir, there must be gaps in
the upper impermeable units. This type of topography can be seen in
valleys and cliffs. Because the pressure inside the aquifer is higher
than the atmospheric pressure, the water is forced out of the gaps and
contributes to either lakes or river systems.

15. 4. Deep seated springs:
Springs due to deep-seated water may be divided into two classes, according
to their geographic distribution, with respect to localities of volcanic or
tectonic disturbance. Their relations to the structure of the upper part of the
earth's crust and the probable character of the fissures in the zones of fracture
which permit the water to rise are shown diagrammatically in Figure

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