Geography and Environment

Activity 11.2

Rivers in Rwanda

A river is a mass of water flowing in a defined channel. A river takes a definite direction from its source to the mouth. Rivers originate from highlands, forests and wetlands such as swamps.

Small rivers are called streams. Streams naturally derive most of their water from precipitation in the form of rain and snow. Many streams join to form a river. Rivers are either permanent or seasonal. A permanent river is one that has continuous flow throughout the year when there is normal rainfall. A river whose flow decrease or cease for weeks or months during the dry season or onset of drought is said to be seasonal.

Rwanda has many rivers. Most of these rivers are found on the western part of the country. All these rivers pour their water into Lake Kivu. However, other rivers are found in different parts of the country.

Activity 11.3

Copy the following table that shows the major rivers in Rwanda. Use the Atlas internet sources or any other relevant materials to complete the table.

Swamps in Rwanda

A swamp is a low lying area that is seasonally or permanently covered by water. It is also referred to as a marsh. In Rwanda, swamps are found in areas such as Kamiranzovu and Gishoma and vallies of major rivers such as Nyabarongo, Akagera and Akanyaru. Others are found on the edges of lakes Mugesera, Sake, Ruhondo and Burera.

Activity 11.4

1.  In groups, use the atlas to identify swamps and wetlands in Rwanda.

2.  Discuss some economic activities that take place around swamps and wetlands.

Lakes in Rwanda

A lake is an area of irregular size filled with water, found in a basin. It could also mean a hollow on the earth’s surface occupied by water. Lakes are either natural or human-made. They are particularly varied in terms of origin, size, shape and depth. In addition, lakes may be fresh-water or salt-water. A lake usually has a river or stream draining into or out of it.

Activity 11.5

1.  Use the Atlas trace out the map of Rwanda.

2.  On it mark and name the following lakes: Kivu, Ruhondo, Muhazi, Cyohoha, Sake, Mugesera, Nasho, Mpanga, Ihema, Mihindi and Rwampanga.

11.2 Formation of lakes in Rwanda

Lakes are formed by a variety of processes which include:

    a)   Tectonic or earth movements

    b)   Vulcanicity

    c)    River deposition

    d)   Human activities

Lakes formed by tectonic or earth movements

Earth movements involve faulting and warping of the earth’s crust. This causes downwarping, tilting and faulting of the crust producing tectonic basins. Water then collects in these basins either from streams or from underground sources. This way, a lake is formed. Lakes formed this way are long, narrow, deep and steep sided. For instance, Lake Kivu was formed by faulting while Lake Muhazi was formed by crustal warping.

For you to find out:

In pairs, find out from various geographical documents and the Internet an example or examples of a lake or lakes formed as a result of tectonic or earth movements. Write short notes for class presentation.

Lakes formed by vulcanicity

There are two types of lakes formed by vulcanicity. These are:

     •Crater lakes                          • Lava-dammed lakes

Crater lakes

The lakes are formed when amassive explosion or collapse of the top of a volcano occur leading to the formation of a depression. Water may collect in such hollows forming a lake. Such lakes are characteristically circular in shape. They have no outlets and are generally salty. A crater lake in Rwanda is found on Mt Bisoke.

Lava-dammed lakes

They are lakes that form when lava solidifies across a river course, creating a barrier. The barrier blocks the flow of a river, forming a lake.

Examples of lava-damed lakes are Burera and Ruhondo.

Lakes formed by river deposition

Oxbow lakes

These are lakes that form along the course of a river. The lakes are formed in the lower course of the river where it flows through meanders or pronounced bends.

How do such lakes form?

Step 1: The outer side of bends is eroded away more rapidly than the inner side.

Step 2: With time, the river cuts through the narrow neck of the meander. This isolates a horse shoe-shaped lake called an oxbow lake. The lake is separated from the river channel by deposition of sediments.

Step 3: When an oxbow lake dries up, it forms a meander scar.

Examples of oxbow lakes are lakes Ihema and Hago on Akagera River.

The diagrams below show how an oxbow lake forms.

Alluvial lakes

These are lakes that are formed by river reversal in depressions. Examples of such lakes are Rweru and Cyohoha.

Human-made lakes

These are lakes formed as a result of blocking or deliberate construction of a dam blocking across the narrow steep sided section of a stream. Water accumulates behind the dam to form the lake or water reservoir. Examples of such lakes include Ntende, Kanyonyomba (in Gatsibo) and Kabgayi (in Muhanga District).

11.3 Importance of water bodies in Rwanda

Water bodies in Rwanda provide water both for domestic and industrial use. The water sources also provide sites for aquatic life. The government also benefits from water sources. For example, some of them are tourist attraction.

Activity 11.6

In groups, discuss the importance of the following water bodies in Rwanda:

     i. Rivers

     ii. Swamps and wetlands

     iii. Lakes

Present the findings to the class for further discussion.

From the class discussion, it is evident that water bodies such as lakes, rivers and swamps are of significance to Rwandans as follows:

a)  Water is important for good health. Our bodies need about 8 glasses of clean and safe water every day.

b)  Rwanda gets water for domestic, industrial use, irrigation and hydro-electric power production from rivers and lakes.

c)  Water bodies are natural habitats for a variety of unique plants and animals. They form tourist attraction sites for recreation. Sport fishing, and boat racing are also practiced. The picture below shows a hotel on the shores of Lake Kivu.

d)  Lake Kivu modifies the climatic conditions of the adjacent areas. Sea breezes and convectional rainfall are common.

e)  The water bodies provide natural route ways to transport goods and people. Some like Lake Kivu provide a link between Rwanda and her neighbouring countries.

f)  Swamps act as natural water purification sites. They also serve as sources of water for lakes. They connect rivers in the country such as Kamiranzovu in Nyungwe and Rugenzi in Burera. The swamps also help in ground water recharge.

g) Water bodies form major inland fresh water fisheries which is a source of food, and income for families and communities.

h) Some lakes are sources of minerals. For example, methane gas is mined from Lake Kivu which is a source of energy.

i)  Sand and clay scooped around the water bodies is used in building and construction.

11.4 Challenges to obtaining sustainable and clean water in Rwanda

Activity 11.7

Gahigi was diagnosed with cholera when he visited a hospital in their district. It was found that he had drank contaminated water from a nearby river.

    1.  In pairs, describe the factors that could have contributed to contamination of the river water.

    2.  Explain ways of purifying water..

Water directly influences the quality of people’s life, their health and productivity. Access to clean and safe water is therefore important. Although Rwanda possesses abundant water resources, there are challenges to obtaining clean water. Some of the challenges are:

a)  People lack comprehensive information and awareness on the importance of careful use of water resources. They also lack adequate infrastructure to harvest and store water.

b)  Climate change has contributed to degradation of water bodies with a decrease in amount and quality of water. For example, the quality of water deteriorates during floods and times of drought.

c)  The conversion of wetlands to agricultural farms has increased rapidly due to scarcity of farmland. This has led to enormous pressure on the wetlands as sustainable sources of water.

d)  There has been an increase in demand for food due to increasing population. This has led to use of fertilisers necessary to boost agricultural production. When used in excess, fertilisers are washed into lakes and rivers. This encourages the rapid growth of water plants on water surfaces. This is not only threatening to the lifespan of lakes and rivers but also has detrimental effects on water quality.

e)  The discharge of untreated waste (both domestic and industrial) directly into water bodies causes water pollution. This has rendered water unsuitable for direct consumption and increased the cost of treatment before utilisation.

f)  Increased infrastructural and housing developments associated with urbanisation has led to lowering water infiltration and increasing runoff. The double negative effect has increased soil erosion and chances of flooding.

11.5 Conservation and management methods of water bodies in Rwanda

Activity 11.8

When a new development affects a community, a public meeting is often held to pass information to the local people and allow them to air their views.

1.Using a dictionary, differentiate between conservation and management.

2.In groups, write down five key factors you would give the community as the advantages of managing water bodies.

3.Explain methods of purifying water used in homes and industries.

Share your answers with other group members.

Over the years, there have been various challenges in the water sector in Rwanda.

Water management refers to the effective planning and control of the processes and activities that are likely to cause worsening of water resources.

Available options for providing safe drinking water include:

a)  Developing and maintaining strategic boreholes, traditional dug wells, water pans and supply lines to improve access to water.

b)  Increasing capture and storage of rainwater to ensure availability of water during the dry season, particularly roof harvesting at household level.

c)  Organising focused awareness campaign that simplifies the need for sustainable use of water resources, in a language that is clearer to people particularly those in rural areas.

d)  Involving water users including gender groups, administrators and non-governmental organisations in water resource management.

e)  Enforcing laws against destruction of water resources.

Water conservation

This is the protection and preservation of water resources from destruction or wastage.

Did you know?

The Egyptians were the first people to record methods for treating water. These records date back more than 1,500 years to 400 A.D. They indicate that the most common ways of cleaning water were by boiling it over a fire, heating it in the sun or by dipping a heated piece of iron into it. Filtering boiling water through sand and gravel and then allowing it to cool was another common treatment method.

Activity 11.9

Take a walk in the area surrounding your school. With the help of your teacher, identify measures put in place in order to conserve water in the area. Take notes for a class discussion.

Water can be conserved through:

a)  Recycling/re-using: This refers to utilising wastewater from one process to another where lower-quality water is acceptable. This is meant to reduce the amount of wastewater, pollution and all together increase water supplies.

b)  Treating or disinfecting community wells and boreholes during drought and floods. This is to maintain water quality.Water treatmentis the process of cleaning water. Treatment makes the water safe for people to use. Treatment includes disinfection with chemicals to kill any germs in the water.

Sustainability of water is the continual supply of clean water for human uses and for other living things.

c) Removing invasive plants: Physical removal of the alien plants is a low-cost measure to improve an area’s water quality.

d) Promoting community empowerment initiatives through high value economic activities such as fishing, beekeeping as well as value addition so that communities are motivated to protect the water catchment areas.

e)  Protecting water catchment areas/water towers, river banks and water bodies from destruction and contamination.

For you to find out!

How can you ensure that water is conserved at home?

END OF UNIT REVISION EXERCISE

1.What is the origin of water bodies in Rwanda?

2.a) Draw a sketch diagram of the feature below.

   b) Use simple diagrams to describe how it could have formed.

3.  a)  Describe how Lake Kivu was formed.

      b)  Explain how communities make use of the waters of Lake Kivu

4. Match the following activities with the correct process.The first one has been done for you.

5. Supposing you are a member of the water club, you have been asked to share with the class wise use of water.Prepare five key points for the presentation.