ACHIEVING A BALANCE BETWEEN HUMAN AND WILDLIFE HABITATS IN A NATURAL RESOURCES DEVELOPMENT PROJECT

Abstract: The reservoirs provide irrigation, drinking water, recreation, attract tourism, facilitate aqua-culture and fisheries, and can enhance environmental conditions. Thus, dams and reservoirs have become an integral part of our man-made infrastructure. In the transformation of the natural world into a human environment, the need to develop natural resources means that it cannot be preserved completely unchanged. However, we must ensure that the ecosystem directly affected by a dam and a reservoir are also benefited from it.

The Mahaweli Ganga Development Scheme, which was implemented in the year 1970 was accelerated in the year 1977 with a view to bringing in major socio-economics benefit to the country. In the process, several adverse as well as beneficial impacts on both the natural and human environments have been experienced. Therefore, particular emphasis has been received for the environmental planning aspect, in order to promote effective management of the environmental resources in the area concerned.

Of the four project areas (Systems A,B,C and D) identified for integrated development, only System-B and System-C got underway during the period 1979 to to-date. However, adequate compensation has been provided with infrastructure and water in the transformation of wildlife habitats into human habitats and vice-versa.

1 MAHAWELI GANGA DEVELOPMENT SCHEME

The Mahaweli Ganga Development Scheme (MGDS) has been the largest multipurpose natural resources development project undertaken in Sri Lanka at least in the last five centuries. The sources of water for the MGDS have been the Mahaweli river, the largest and longest river in Sri Lanka and the adjacent rivers in the project area. There are thirteen independent development areas in the MGDS identified as System-A, System-B, System-C …. System-L and System-M. Of the thirteen Systems, H, B, C, G and L have either been fully or partly developed up to now, having implemented the project in the year 1970. The principal proposals of the scheme, in view of the socio-economic problems faced by the country in the sixty decade were as appended below:

2 PLANNING CONCEPTS

The cardinal concept encompassing the MGDS has been the Man, his Habitat and his Economy within an integrated development system. The fundamental issues on which the entire scheme was based were, irrigated agriculture, human settlement and environmental conservation. The development of suitable lands for agriculture by means of gravity irrigation has been the principal concern in the planning.

Many, integrated development projects based on irrigation and human settlement cause environmental changes during and after development. When planning such projects, it is important to address environmental issues, which may arise due to various changes taking place in the different systems of the environment. Each system or sub-system can therefore, be represented by the Terrestrial, Aquatic and Human environments, to which all functions in a system are related.

The key resources, which are involved in these three environments are the water, land, flora, fauna and human.

3 ACCELERATED MAHAWELI GANGA DEVELOPMENT SCHEME

In the year 1977, the government decided to accelerate the implementation of the MGDS. It was envisaged that the acceleration would include the following:

The lowland extents which were to be brought under irrigated agriculture are shown tabulated below.

Reservoir	Surface area at FSL (Ha.)	Net storage capacity (MCM)	Irrigation Potential (Ha.)
(1) Kotmale	970	408	20,000
(2) Victoria	2270	690	53,000
(3) Randenigala	2750	860	35,000
(4) Rantembe	-	21	-
(5) Ulhitiya/Rathkinda	2270	146	-
(6) Maduru Oya	6280	430	16,000

4 TERRESTRIAL ENVIRONMENT

Climatic conditions in the project area are largely influenced by two annual monsoon seasons. From October to February, the area is generally under the NE monsoon. The SW monsoon prevails from March to September. The mean annual rainfall ranges from 1650 mm in the lowlands to 5300 mm in the mountains, where Kotmale, Victoria and Randenigala are situated. The annual temperature variations are generally less than 5℃ from the average 27℃ across the lowlands. Throughout the dry zone, the annual evapotranspiration rates normally exceed precipitation levels. The land uses of Systems A,B,C and D by the year 1979 are shown in the table below.

Development Area	Improved lands (Ha.)	New Lands (Ha.)	Other crop lands cultivated (Ha.)	Total cultivated (Ha.)
System - A	3,500	14,000	-	17,500
System – B	8,850	25,800	5,500	40,150
System – C	-	19,550	-	19,550
System - D	2,000	10,950	5,000	17,950
Total	14,350	70,300	10,500	95,150

5 AQUATIC ENVIRONMENT

Most of the small reservoirs in the project area could be categorized as highly productive or eutrophie systems, prior to augmentation with diverted waters. A number of villus (swamps) in the project area also support full time fishing activities. The flood-plains provide a valuable nursery grounds for many fish species. Fishing activities are well developed in the estuaries portions of both Maduru Oya and Mahaweli river. Villus (Swamps) are marshy areas which occur in association with the riverine flood-plain. There are more than 50 identified villus in the project area. The flood-plain of Mahaweli river occupies about 12,800 Ha. Villus are highly productive biological communities. Villu habitats are very favourable for many wildlife species and high concentrations of birds and mammals are usually observed here.

Mangrove swamps occur in the coastal areas, extending inland with tidal intrusion. However, mangrove swamps in the project area have been substantially reduced due to clearing of jungle. The aquatic weed species, which occur in abundance in the project area include water hyacinth, floating ferns (salvinia), water lettuce and cattails.

6 HUMAN ENVIRONMENT

The overall population in the project area was probably around 200,000 by year 1979 or so. In the year 1979 the total population in System-B was estimated at 25,515. There were four reported aboriginal villages. The total population in System-C in the year 1979 was 29,776. A rough approximation of population in both Systems A & D had been 30,000 and 100,000 respectively.

The land alienation policy adopted in the settlement planning and implementation in System-B and System-C under the MGDS has been as shown below;

The size of a hamlet or a village in Systems B & C is different to that of Systems H, G or L and there are homesteads in the range 200 – 300 in each of Systems B & C.

7 WILDLIFE

The project area was home to a variety of wildlife habitats such as villus (swamps), grasslands and numerous forest types. Several designated wildlife reserves were partly or wholly situated in the project area. A Nature Reserve has to provide complete protection for wildlife while accommodating existing land rights.

The project area inhabits diverse fauna and includes several endangered and two threatened animal species. These species are all found in other parts of Sri Lanka, and except for the toque macque, purple-faced langur and red-faced malkoha, are also distributed in other parts of the world. However, all nine species are generally considered to be threatened or endangered in their respective world distributions.

Of the endangered/threatened species, the Bengal monitor has the most extensive distribution within the project area. The red-faced malkoha is confined to the riverine forest in the northern part of System-C. The toque macaque and purple faced langur are most commonly found in riverine forest or near major reservoirs. Leopards were relatively numerous in northern part of System-C. Similarly, elephants were abundant in northern part of System-C and in the Somawathie National Park. Of the estimated total of 2000 wild elephants remained in Sri Lanka, about 800 were presumed to inhabit the project area. In the dry season, elephants and other wildlife tend to congregate in the vicinity of perennial streams, reservoirs, swamps or in riverine forests. As surface waters rise with the onset of the monsoon rains, they disperse and enter upland areas where they graze throughout the wet season.

The project area was also the natural habitat for a number of endemic animals who are found only in Sri Lanka. These include eight species of fish, four amphibians, nineteen reptiles, eight birds and three mammals. Furthermore, 53 endemic plant species and 23 very rare plants have been identified as occurring in the project area. In addition, large mammal species such as wild boar, sloth bear, deer and sambhur were also observed in the project area. Also, majority of the 251 resident bird species found in Sri Lanka were observed in the project area. During the winter months elsewhere, about 75 more bird species migrate into the area from Europe and other countries in the region.

Some field surveys conducted in the late 70’s had indicated that a high level of wildlife activity, was identifiable for certain localities in the project area. There were categorized as “critical habitats”. and included, Somawathie National Park, Mahaweli Flood Plain between Wasgomuwa and Somawathie National Park, Northern part of System-C adjacent to Wasgomuwa National Park and Wasgomuwa National Park.

8 ENVIRONMENTAL IMPACTS ON HUMAN SETTLEMENTS AND WILDLIFE

A significant social impact of the development exercise has been the transition from small isolated village, societies to production oriented large scale colonization schemes. The population of the project area was expected to rise drastically by one million people.

New settlers are compelled to use guns to scare encroaching animals, causing loss to the wildlife. Extensive extents of wildlife habitats have been removed in clearing the forest and creating human habitats. Based upon previous records, a reasonable estimate of crop loss in project areas of this nature has been about 20% due to physical wildlife damage and feeding.

Due to clearing, a large portion of the forest in the project area was lost, resulting greater need for timber and fuel wood. There have been a loss of large numbers of animals and plants, many from the nine endangered and threatened species or more than 90 endemic species. The carrying capacities and population for most wildlife species have declined. The viability of the endangered species have been further reduced. The critical wildlife habitats of extents 5500 Ha. and 15,000 Ha. In Somawathie National Park and in system-C respectively have been eliminated. Breeding and feeding grounds for a number of fish species, waterfowl and migratory birds have been lost.

9 LAND ALLOCATION FOR HABITATS

Of the four systems A,B,C and D in the project area, only Systems B and C have been developed up to now, with the provision of irrigation and social infrastructure, facilitating irrigated agriculture and human settlement.

It was envisaged with the implementation of integrated rural development, in System - B and System - C that 45,000 and 28,000 farm families would be inducted into the project area for irrigated agriculture. The irrigation and social infrastructure necessary for the new society of people would be provided replacing the natural forest and the wildlife.

However, the development of new lands for cultivation by the settler-farmers had to proceed at the expense of natural habitats and the fauna and flora associated with them. The social values derived from cultural and religious practices and spiritual traditions in Sri Lanka demand the need to balance development goals with wildlife conservation.

Therefore, it was considered to implement the most feasible means of conserving the wildlife species by providing as much contiguous natural habitat as possible. The recommendation was to expand the wildlife reserves and give legal protection. The recommendation was implemented creating the under mentioned national parks, forest reserves and sanctuaries afresh, to compensate for the area acquired by the human settlements displacing the occupants of the forest and the water bodies, prior to development.

System	Gross Area (Ha.)	National Park/Forest Reserve/Sanctuary Name	Extent (Ha.)
B	151,000	Maduru Oya National Park	58,850.58
B	151,000	Thrikonamadu National Park	25,019.00
C	70,000	Wasgamuwa National Park	36,947.99
B & C		Flood Plain National Park	17,350.70
Sub Total	221,000		138,168.27
A	92,600	Somawathiya National Park	37,762.19
A	92,600	Riverine Nature Reserve	824.15
D	108,000	Victoria, Randenigala, Rantembe Sanctuary	42,087.37
D	108,000	Minneriya – Giritale Nature Reserve	9,452.86
Total	421,600		228,294.84

References

[1] De Alwis, Dharmasiri (1990). Impacts and Implications of minor reservoirs on irrigated agriculture, human settlement and natural environment, University of Canberra, Australia.

[2] TAMS, Engineers and Architects, (1980). Main Report on Environmental Assessments of Mahaweli Ganga Development Program, Ministry of Mahaweli Development, Sri Lanka.