Tidal Lowlands, Evaluation of Guidelines for Development

Kimpraswil

In cooperation with

Rijkswaterstaat

Lowland development in Indonesia 

Out of the 162.4 million ha land resources in Indonesia, about 39.4 million ha are coastal lowlands (24.2%) and about 123 million ha uplands (75%). The lowlands have their characteristics in accordance with their geographical and hydro-topographical conditions. Based on those conditions they can be divided into two subgroups, i.e. coastal swamps and inland swamps. The coastal swamps are influenced by tidal fluctuations while the inland swamps are influenced by river flood plain characteristics. The total population of Indonesia is 217 million in 2002 and the projected population is 318 million by the year 2050.

The reclamation process of coastal strips in Indonesia was practiced by the Buginese and Banjarese since more than 100 years. The main purpose was to find new living space for new generations because of the limitation of further expansion possibilities in the village of origin. Most of the Buginese had many years of experience in the practice how to reclaim tidal lowland areas. They reclaimed those lands mainly for agricultural use and construction of their homestead. 2 million ha of land have been reclaimed sofar along the Eastern coast of Sumatra (Riau, Jambi, South Sumatra and Lampung), and along the Western and Southern coast of Kalimantan. 

In the Sumatra and Kalimantan islands the typical characteristics of coastal tidal lowlands are (Heun, 1993):

-        rainfall is in the order of 2,000 - 2,500 mm per year with 5 - 8 wet months and 1 - 3 dry months;

-        evaporation (Penman) ranges from 3.5 - 5.5 mm/day;

-        field levels before reclamation are typically at about Mean High Spring water level in the wet season;

-        tidal gravity irrigation can only be applied in 10 - 15% of the area;

-        potential for pump irrigation is restricted by water quality (salinity, acidity). 

Since 1960, the Indonesian Government was reclaiming tidal lowlands. The reclamation of tidal lowlands in Indonesia has to create a suitable environment for agricultural development and settlement. The objectives were to:

-        increase the national food production, mainly Rice, in order to obtain self­ sufficiency;

-        provide agricultural land for transmigrants, in order to support the Government Transmigration Programme;

-        support regional development;

-        increase the income per capita;

-        increase the security on coasts along the border lines.  

Some results of an inventory study on coastal lowlands which was carried out in 1985 are presented in the Tables below.

The tidal lowlands are remote and uninhabited. Tidal lowland development by the Government took place primarily along the East coast of Sumatra, in South and West Kalimantan and in the Southern part of Irian Jaya to accomodate settlers from the over populated islands Java, Bali and Madura. Tidal lowland development gradually gained momentum for agricultural development in Indonesia because, mainly in Java, there is a continuous loss of fertile agricultural lands for residential and industrial development. It was estimated that the rate of the loss of agricultural land is about 30,000 ha/year. 

Swampy land resources in four majors islands in 1,000 ha

 Tidal lowlands in Indonesia in 1,000 ha that are suitable for agricultural development

From 1985 – 1995 there were almost no new reclamation projects by the Indonesian Government, main focus was on improvement (phase II) of reclaimed areas. Since 1996 new reclamations started in South and Central Kalimantan, mainly in river flood plains. In these schemes, due to the different river water levels during the wet and the dry season, in addition to irrigation and drainage, also flood protection is needed. Due to the need to increase food production it will most probably be a must for the Government to undertake new reclamation project in future, together with phase II and phase III developments. 

Coastal lowland development in Indonesia has been carried out as a gradual long term process, known as the stage-wise development strategy which started in stage I, with open, uncontrolled water management systems and would have to end with fully controlled systems (polders) in stage III. In stage II some hydraulic control structures would be completed in order to improve the agricultural performance of the scheme. This strategy was based on the following considerations:

-        limited availability of construction budget, and the need to reclaim large areas;

-        lack of knowledge, experience and design criteria;

-        the social cultural background of the transmigrants. Most of them were coming from ‘dry’ land areas and not familiar with wet tidal land conditions. 

The stage-wise development strategy was a good approach especially for Indonesia where the farmers were themselves involved in the establishment of scheme and learned to set up water board organizations for small hydrological (basic) units with relatively simple tasks. Besides this advantage of the stage wise approach, there were some disadvantages (Heun, 1990), i.e.:

-        development of the reclamation unit(s) was too slow in general and it will take a long time to reach the final development stage;

-        because of small investments during the first stage, it was very difficult to reach production above the subsistence level;

-        financial supports are still needed for the second and third stage of the development program, so the total amount of financial support could be higher then if a high cost approach was applied immediately. 

Nowadays, most of the reclamation schemes are in the beginning of the second development stage. The large areas of coastal tidal lowlands are not yet well developed but their potentials might be considered as important means for increasing food production (self-sufficiency) including crop diversification and providing settlement areas for transmigrants. 

So far, the Indonesian Government (mainly the former Ministry of Public Works and the Ministry of Agriculture) had the responsibility for the design, operation and maintenance of primary and secondary drainage canals. Tertiary and field canals are the responsibility of the farmers.  

Rainfall (amount and distribution) in the wet season is adequate for one Rice crop. Additional irrigation (low lift pumping) for wetland Rice may provide a high yield under proper soil and water management. But tidal lowlands are located in remote areas, hindering supply of inputs and marketing of products. In addition, close to the river mouth, salinity may create problems for agriculture and drinking water, especially during the dry season. 

A substantial part of the tidal lowlands is covered by (potential) acid sulphate soils or peat soils. Soil development takes time before a stable situation is reached. Soil and water management and the related infrastructure have to be adjusted to the changing conditions. 

Presently most of the schemes have operation and maintenance problems and there is lack of integration. Several attempts were made by the Indonesian Government to improve the water management in order to attain sustainability, but this has not been very successful. In 1999, a new set of policies was promulgated by the Government to hand over the responsibility of operation and maintenance to the water users associations regardless of the size of schemes.