PART II
Country papers presented at the consultation

Burundi country paper
The characterization and classification of wetlands for agricultural production

Introduction

Burundi is situated in the region of the great lakes. In latitude between 2°45' and 4°28' South. In longitude it is between 28°45' and 30°50' East. The surface area is 27 834 km² of which 2 634 km² are occupied by Lake Tanganyika water. Neighbouring countries are: Democratic Republic of Congo in the West, Tanzania in the East and South and Rwanda in the North. There is no access to the ocean.

In 1993 (before the war) the population was estimated at six million with a mean density of 230 persons/km².

In Burundi the area covered by wetlands is about 112 000 hectares. 80% of this is appropriated to agriculture of which 56% is currently cultivated (Figure 1). Swamps in Muyinga, Ngozi and Ruyigi provinces occupy 70% of the total surface area of the swamps in the country (Figure 2).

Characterization and classification of wetlands

Wetlands can often be classified according to their location, water quantity, vegetation and the soil. Peat represents vegetation and animals that are accumulated under water and are not completely decomposed and the organic matter is more than 60% dry weight. Organic soil contains 30 to 60 % organic matter. Swamp is an area that is formed on organic soil.

Wetlands can be classified according to:

a. Geography (Altitude)

In Burundi, altitude varies between 775 metres (Lake Tanganyika) and 2 670 metres (Crest Zaire - Nil). The ecology and agriculture in wetland authorized the subdivision into four altitudinal zones

Etienne Kayengayenge 
Directeur général de l'aménagement du territoire et de l'environnement 
Cyprien Ndayegamiye 
Directeur général du Suivi-Evaluation 

with different climates and agronomic possibilities. Peat bogs are limited to altitudes between 1 650 metres and 2 300 metres. However, below 1 650 metres and as low as 1 300 metres, they can only be found in drowned valleys.

b. Water level

Depending on the free water height or the slick, one can distinguish four types of swampy formations:

1. Water is free with weak flow and without vegetation.

2. Water is stagnant on the whole surface and covered by a lot of vegetation. Sometimes the water depth on the surface is very deep.

3. Water sometimes emerges and drowns vegetation, especially during the rainy season.

4. Water is some centimetres below the soil surface and fluctuates with seasons.

c. Vegetation association

Deuse (1969) proposes in the diagram in Table 1 the relationship between soil - water - plant and the altitude in swamps and peat bogs. The proposition is simply classified as follows:

1. Swamp of papyrus: characterized by too much water and most of the vegetation is cyperus papyrus.

2. Swamp of cyperus latifolius: Water is less than in swamp papyrus. This swamp is regularly cultivated in dry seasons. Its whole surface is covered by cyperus latifolius which grows on forsaken lands.

3. Spongy valley: Water level never touches the ground but stays in the subsoil. The vegetation is bushy with tall grasses below.

4. Grazing valley: Water never covers the valley which is often very narrow. This valley is used for animal grazing during the dry season.

TABLE 1

Relations between soil and vegetation in swamps and peat-bogs

d. Organic matter and soil

The classification proposed by Pahaut (Bodeux, 1961) during the a research on Karuzi swamp named Nyabimo distinguishes these soils as: peat-bog mud and sand with mud.

Inventory and mapping of wetlands

Methodology and tools

Burundi and Rwanda are similar concerning topography, geology and agro-climatology. That is why there has been a proposal to use in Burundi the same inventory methodology of swamps used in Rwanda by PNUD/FAO/RWA/89/006 Project (see Rwanda country paper).

In general, Burundi swamps are presented like complex groups bordering the main hydrographic systems. The hydrological flow of these complex groups is directly determined by the basin conditions at the upper waters. Consequently it is very important to adopt a basin approach during swamps inventory. First of all the hydrological flow must be established, including the whole river system and the lakes (Figure 3).

The territory is divided into basins, each one containing complex swamps more or less wide and ramified. Then these complex swamps are divided into smaller swamp pieces. One swamp piece is a unit of the inventory.

Mapping

We can obtain different degrees of mapping:

• Basin maps by region. Map scale = 1:100 000.
• Maps for basins and complex swamps produced by the inventory for the whole country. Map scale = 1:50 000. On these maps we can identify the limits of the basin area and localize the complex swamps.
• Short swamp piece maps for the whole country. Map scale = 1:50 000.

Sustainable development

Sustainable utilization of a wetland is defined as human use of a wetland so that it may yield the greatest continuous benefit to the present generation while maintaining its potential to meet the needs and aspirations of future generations. Natural properties of the ecosystem are defined as physical, biological or chemical and nutrient resources and the interactions between them. In this context the wise use concept will promote national wetland policies through a long term process and through emergency actions at specific sites, whether or not they are on the list of "Wetlands of International Importance".

Although wetlands are rightly still seen by many people as underused in Burundi, there has been a growing realization of their value during the last years and many things are being done presently.

Government, through research institutes (ISABU, FACAGRO), has devoted enormous attention to wetlands and has reached a better understanding not only of their physical and biological importance, but also of their social, economic and cultural functions.

We must realize that Burundian knowledge in wetland management is still limited. This is the reason why there is fear of the wrong approach when cultivating a wetland.

In summary, management policies are being improved now. A study on guideline diagrams for wetland management and development was recently published. This document will serve as a database for wetland development and, in connection with this, a project should start immediately unless it encounters resource problems.