UNDERGROUND WATER

UNDERGROUND WATER

UNDERGROUND WATER

This is the water found below the earth surface in pores of permeable rocks and above an impermeable rock layer.

Also called groundwater

INFILTRATION

The movement of water vertically into the soil/rocks through pores, cracks or joints

PERCOLATION

The movement of water downwards and horizontally in the rocks/soil

EFFLUENT STREAMS

Underground streams supplied with water from the water table above them

INFLUENT STREAMS

They are underground streams supplied with water from the water table below their level

SOURCES OF UNDERGROUND WATER

There are four sources of underground water:

•   Rainwater;
•  Melt water
• Lakes, seas, oceans, rivers and swamps
• Magmatic water/ plutonic water; this is the water that gets trapped in the rocks beneath the surface during volcanism

Factors Influencing Existence of Underground Water

Precipitation/ rainfall:

Little rainfall has little or no infiltration as most of the water evaporates

Little rainfall over a long duration, gives time for infiltration, increasing underground water

Heavy rainfall in a short period has more surface run-off, and has little time for infiltration

Heavy rainfall over a long has more infiltration as it saturates the ground, increasing the underground water.

Slope gradient

Flat gentle slopes gives water more time to infiltrate into the ground, as it remains in the same place for long duration

Steep slopes have more run-off, and therefore water has little time to infiltrate into the ground.

Vegetation cover

Vegetation hold water on the ground by reducing surface run-off, giving water more time to sink.

Bare ground has more surface run-off and has little surface run-off

Plants also break the speed of rain drops, giving the water time to infiltrate into the ground

Level of saturation

Dry ground/soil has more open spaces which allows for more infiltration of water

Saturated and wet soils have minimal spaces to hold water reducing infiltration

Evapotranspiration

High rate of evaporation caused by low moisture content in the atmosphere reduce the amount of water that infiltrates into the ground

Evapotranspiration reduces the amount of water in the soil/ground. This makes the soil dry, increases the spaces in the soil, and in turn increases infiltration.

Nature of the rocks

Permeable rocks allow water to penetrate through.

Highly permeable rocks allow for a lot of infiltration.

Impermeable rocks do not allow water to penetrate through, reducing the level of infiltration

Some rocks such as clay allow water to enter them but does not allow it to pass through. This is because when clay particles absorb water, they expand reducing the air spaces, preventing percolation of water

Note

An aquifuge; is an rock that does not allow water to pass through/ infiltrate e.g. gabbro, shale and slate

A porous rock; is permeable rock that has air spaces/pores between the rock grains

A Pervious rock; is a rock that has cracks, fractures and joints through which water enters

DESCRIPTION OF HUMAN ACTIVITIES ON TOPOGRAPHICAL MAPS

Factors Influencing Crop Farming on topographical maps

Drainage: Well drained area encourages crop farming

Poorly drained/ swampy areas/ dumpy areas waterlogged areas discouraged crop farming

Availability of well-developed transport network: for transportation of the farm produce to the market/ to factories e.g coffee/ tea farming has well connected/feeders roads to the respective factories

Gently sloping land; encourages crop farming such sugarcane/rice/ wheat for mechanization

Steep slopes discourages agricultural activities because of challenges in mechanization and accessibility through transport networks.

In semi-arid arid areas, availability of permanent rivers/lakes; to provide water for irrigation

Cool conditions due to high altitudes evidenced by contours rising over 1500m(a.s.l) which is suitable for growing crops such as tea, coffee\

High rainfall adequate for growth of crops evidenced by forests and many permanent rivers

Availability of adequate labor to work crop planting and harvesting; evidenced by high density settlements around the farms

 

Factors Influencing Livestock Farming On Topographical Maps

Availability of water for cattle drinking; from many rivers (give examples of rivers on the map)

Availability of pastures; suitable for animal grazing evidenced by woodlands, scrubs, and thickets

Availability of veterinary services; for improved animal husbandry evidenced by veterinary offices/ investigation laboratory/ cattle dips/ animal research stations (indicate the areas where they are located on the map)

Large tracks of land; shown by sparse settlements providing extensive land for grazing animals. Gently sloping land; for easy movement of animals evidenced by widely spaced contours

Cool conditions suitable for dairy cattle rearing; shown by high altitude contours above 1000m a. s. l

Availability of transport for transportation of cattle and dairy products to the market; shown by many roads and tracks

Availability of market for cattle and cattle products; indicated by dense settlements

Factors Influencing Trading On Topographical Maps

Presence of numerous market centers/ trading centers/ shops; which provide opportunities for trade (indicate the areas where the centers are located)

Well-developed transport network; evidenced by road networks/ railway (give specific type of roads in the area covered by map e.g. all-weather roads)

Availability of market for consumption of variety of goods and services; evidenced by dense settlements/ numerous settlements

Numerous economic activities ; evidenced by tea/coffee/cotton factory/sugarcane factory/ dairies/ fisheries research centers/ cattle dips/ quarries/ murram pits; which provide products for trading

Factors Influencing Transport and Communication on Topographical maps

Relief:

·         Roads are constructed on gentle slopes, avoiding steep areas

·         Roads are relatively straight on lowlands/plains/ gently sloping areas because it is easier to construct in such areas

·         Roads are built meandering up the steep slopes to reduce steepness

·         Roads and railways are built around hills and ridges to avoid steepness and reduce the cost of  construction

·         Bridges/culverts are constructed where roads and railways are crossing deep valleys/ rivers

Drainage:

·         Roads and railways are constructed away from swamps due to flooding

·         Bridges are built across rivers

·         Ferries are used to cross wide rivers

Forests

·         There are few/no roads across forested areas as government policy to preserve forests

·         There are few/no roads in forested area as it is difficult to clear forests, and would make road construction expensive

·         There are few/no roads in forested areas because there are no settlements

Natural Resources

·         Roads and railways are constructed to join ares rich in natural resources e.g. minerals/ rich in agriculture for transportation of the products to the market

Density of Settlements

·         Dense network of roads are built in densely settled areas

·         Low density/sparsely settled areas have few roads

Example

Using evidence from Karatina map give three economic activities which they were able to identify

·         Crop farming e.g. tea farming evidenced by tea centers ,coffee farming evidenced by coffee factories ,at Kiaragana, Uramathi etc

·         Transport due to presence of roads leading in and out of Karatina town.

·         Industrial activities evidenced by coffee factories in Uramathi ,Kiaragana etc

·         Commercial due to the presence of markets like Kianga,Miiru,Kiriko etc.

Using evidence from Karatina map, identify two farming activities taking place in the mapped area.

•   Cattle rearing /livestock keeping evidenced by cattle dips slaughter house and Matuto salt lick
•   Fish farming  shown by existence of fish research  center in GS 8560 and fisheries department in Karatina town
• Plantation farming plantations within Mt Kenya
• Coffee growing shown by presence of coffee factories
•   Tea growing evidenced by tea centers