Ground water and surface waters

Question 1

The most important hydrological quantity associated with water supply is

Answer 1

Run-off.

Run-off describes how much water that has been raining flows on the ground and into the surface waters.

Question 2

What influences the amount of run-off?

Answer 2

Rain and evaporation.

Question 3

What is groundwater?

Answer 3

Groundwater refers to water that has been filled the open spaces of soil and bedrock.

'’The substance or energy shall not be treated in such a way that the quality of groundwater may become hazardous to health or otherwise materially deteriorate or become unfit for the purpose for which it could be used.’’

Question 4

Groundwater areas are classified to three categories:

Answer 4

1. Areas of groundwater for water supply. The area is defined as those used or will be used within 20 to 30 years for AT LEAST 10 household needs.
2. Other groundwater areas suitable for water supply. Suitable, but no demonstrable use for them.
3. The exploitation of groundwater in category 3 areas require further classification.

Question 5

Groundwater formation in Finland?

Answer 5

Most Finland’s soils have formed of poorly water-permeable clay and morennum deposits.
So, the best groundwater reserves in Finland are located in ridges and various gravel deposits that have formed during Ice Age.

Question 6

What is groundwater exploration?

Answer 6

A multi-stage process in which field studies provide the basis for actual test bumps and the construction of production wells, as well as generally for determining the hydrogeology of the area.

Question 7

The most important for the formation and sourcing of groundwater is?

Answer 7

The deposits and coarsely sorted material.

Coarse-grained earth deposits have a high pore volume and good water conductivity.

Question 8

Why is water supply easier in the edges?

Answer 8

Because the groundwater level is closer to the ground surface than in the central parts of the formations.

Question 9

How is earth water zone formed?

Answer 9

In the earth water zone between ground surface and groundwater, water fills the soil’s pores and bedrock hair cracks only partially.

Question 10

How is groundwater zone formed (last step)?

Answer 10

Bedrock cracks completely and filled with water. Groundwater flows toward the lowest points on the terrain and erupts in some places into the ground or water bodies by gravity or pressure.

Question 11

Gravitational sinking water

Answer 11

Downward moving water under the influence of gravity

Question 12

Capillary water

Answer 12

Attached to and between the earth grains by surface tension forces and is available to plants

Question 13

Hygroscopic water

Answer 13

Electronically bound to the surface of soil particles in a thin layer.

Question 14

Absorbtion of water

Answer 14

Formed of a layer of several water molecules adhered to the surface of earth particles by Van der Waal forces

Question 15

Crystal water

Answer 15

Structurally bound to minerals, rich in clay minerals. (100 to 400 C heating relieves it)

Question 16

Groundwater levels in Finland

Answer 16

Usually 1-4 meters, in ridges and bedrock depths of up to 20 meters.
Groundwater is at its highest in spring when snow has melted, lowest in late winter.

Question 17

What determine the slope at which the surface water is set above the discharge levels?

Answer 17

The amount of groundwater formed and the water conductivity of the layers.

Question 18

Variations in groundwater surfaces depends mostly on?

Answer 18

Precipitation and evaporation.
Atmospheric pressure.
Also abstraction, construction, drainage, tides and winds.

Question 19

How can we increase the production of water in groundwater areas when it is not enough?

Answer 19

By absorbing additional water.

In direct artificial groundwater method, the surface water is led (by pumping) into the groundwater area.

Question 20

Indirect groundwater method?

Answer 20

The formation of groundwater is increased by placing the water supply wells close to the surface water.

Question 21

Distance of filtration when making artificial groundwater?

Answer 21

At least 10m.

Question 22

Groundwater area classification

Answer 22

Categories of I to III, mainly on a scale of 1:20000

Key research data compiled (possible info like groundwater abstraction plants, boundaries, levels, flow data, area number etc.)

Each area is filled with groundwater area card.

Question 23

The municipal folder of groundwater consists of

Answer 23

Water needs assessment with justification, reports of groundwater areas and their use, protection recommendations etc.
All info is available at SYKE

Question 24

Water supply system consists of:

Answer 24

• Raw water acquisition (lakes, rivers) as groundwater, surface water or both.
• Water treatment at water companies
• Pumping and storing water in lower water tanks or upper water tanks
• Water supply through the water supply network to real estate or other applications.

Question 25

What are the problems associated with surface water?

Answer 25

• High humus content
• Soft (corrosive)
• Prone to contamination
• Hygiene risks

Question 26

Regulation of raw water sources are divided into three categories:

Answer 26

A1: Simple physical treatment and disinfection
A2: Normal physical treatment, chemical treatment and disinfection
A3: Possible pre-treatment and enhanced physical and chemical treatment, further treatment and disinfection

Question 27

Indications of good water:

Answer 27

Odorless, tasteless, colorless and clear

Question 28

KMnO4 of non-polluted groundwater is between

Answer 28

1 and 5 mg/l

Question 29

Where does nitrous compunds (NH4, NH3, NO2) originate?

Answer 29

From rainwater, the degradation of organic matter in soil, fertilizers, waste water from industry, settlements and landfields

Question 30

The potassium permanganate number and the color number represents

Answer 30

The amount and color of the humus and clay of the water, high where elevated levels of iron and manganese are

Question 31

Alkaline of groundwater

Answer 31

More alkaline groundwater exists on coastal areas.
10 fold differences in alkalinity in Finland:
The weakest buffer capacity in Lapland, strongest in South-West coast and Åland.

Question 32

Fluoride is high in

Answer 32

South-East- and South-Finland

Question 33

Nitrates are elevated in

Answer 33

Agricultural cattle raising zone (Savo, South-Carelia)

Question 34

Possible impacts of contaminated drinking water (Which ones)?

Answer 34

Heat resistant coliform bacteria (E. coli) indicate fecal contamination.
Nitrate influences the oxygen absorbtion of small children.
Fluoride impacts bone and teeth formation.
Aluminium.

Question 35

What should be taken into consideration when searching for groundwater areas?

Answer 35

Other studies carried out in the area, as well as other studies related to the conditions in the area.
Geological aerial interpretation provides a good base for designing research points.
Aerial photos + maps = good area identification.

Question 36

What can be seen in more details from aerial photographs?

Answer 36

Information on the humidity, flow direction (color, shape).

The aim is also to determine groundwater discharge sites.

Question 37

How are weather stations used in groundwater area research?

Answer 37

Information of precipitation and temperature in the area is obtained, used to identify water balance in the area.

Question 38

What is one key job for environmental management related to groundwater?

Answer 38

To determine the potential for deposit protection and the measures to pose a risk of contamination in the area.

Question 39

With terrain studies, what is nature value survey for?

Answer 39

Used to map the nature values and valuable habitats of the area. To assess the impact of groundwater abstracts on the habitats.

Question 40

Changes in groundwater levels and flow directions have the greatest impact on?

Answer 40

Bogs, spring, ponds, lakes, streams and rivers, and the vegetation and flora of these sites.

Question 41

Geophysical measurements are used to?

Answer 41

Determine different physical properties of the soil. Elasticity, electrical conductivity, magnetic properties and density.

Question 42

What are low-flight measurements for?

Answer 42

Provides information on the structure of the bedrock and the flight measurement material in an easy-to-process digital format.

Question 43

What are gravity measurements for?

Answer 43

To determine the thickness of the soil cover. This allows the design of the locations of more detailed geophysical measurements and drills.

Question 44

What are aeromagnetic measurements for?

Answer 44

Suitable for determining contrusion zones. It is based on the total value of earth’s magnetism.

Question 45

What are electrical resistance sonars for?

Answer 45

Mainly used to determine elevation positions on groundwater and rock surfaces, and to determine the salt-freshwater interface.

The electrical resistance sonar provides information on the change in the characteristic resistance of the soil mass.

Question 46

Resistance of soil layers depends on?

Answer 46

Example: density, porosity, grain composition, temperature and water content of the soil species.

So, the amount of water in the pores its salinity´and distribution in the pore space have a significant impact on the electrical conductivity of the earth layers.

Question 47

What is ground radar scanning used for?

Answer 47

To examine the soil up to a depth of 30 meters.
Ground radar uses its antenna unit to transmit short (1-6 nanosecond) electromagnetic pulses to the object to be measured. Advanced in the objects medium with a speed of light.

Question 48

What is seismic refraction scanning used for?

Answer 48

Its based on the progression of elastic waves in the soil. In the ground, waves folded from different layers of soil are registered with motion or pressure sensitive receivers.
Also the depth of groundwater can be determined.
Cannot be used in winter, because freezing of the soil increases the seismic speed.

Question 49

What is the use for soil surveys?

Answer 49

When geophysical studies have provisionally determined places favorable for abstraction, soil surveys are refined by digging tests.
In groundwater studies, the most common digging methods are test-bar drilling, vibratory drilling, compressed air drilling and mechanical drilling.

Question 50

What is the advantage of today’s medium-scale multifunctional drills?

Answer 50

It is possible to take soils samples and install groundwater observation tools at the same time.

Question 51

How are groundwater flow and speed measured?

Answer 51

With marker research. Marker is fed to the observation tube.
Substance in the soil is monitored from the observation tubes (multipoint method).
Groundwater flow rate is examined from dilution of the tracer in the observation tube (singlepoint method).

Question 52

Why is test pumping carried out?

Answer 52

In order to determine the environmental impact of water quality, quantity, groundwater deposit load resistance and abstraction.
The amount of water to be pumped shall be at least equal to the estimated water requirement, as the objective is to load the deposit in such a way as to achieve a new water intake equilibrium equivalent to that of water abstraction.