by Hartoyo Suprianto, Sumarjo Gatot Irianto, Robiyanto Hendro Susanto, F.X. Suryadi, Bart Schoultz on Inter-Regional Conference on Environment-Water, Delft, Netherlands

Indonesia avails over lowlands areas with an estimated area of about 34.3 million ha, predominantly in Sumatera, Kalimantan and Papua, out of which about 20 million ha is tidal lowlands are in their natural state generally poorly drained, waterlogged areas and may be regularly inundated for prolonged periods. Almost 4 million ha of tidal lowlands have been reclaimed, partly by spontaneous settlers and partly by the Government. While the reclaimed soils mainly consist of clay these areas generally have a good potential for agricultural development. In the west season the rainfall is adequate for a rice crop and in the dry season for a dry food crop.

For successful tidal lowlands development and management there is a need for adequate water management measures based on soil, water and crop relationships. This paper focuses on water management measures at tertiary level. Some important aspects are:

• physical environment, which includes climate, topographical and hydro-topographical conditions, tides, river hydrology, and soil types;
• role of the hydraulic infrastructure in effective water management.

This will be illustrated with observations during a field survey in November 2005 in and hydraulic model stimulations of a tertiary block in the Telang I area, South Sumatera. The area can be categorized in category A (daily tidal irrigation is possible during wet and dry season) and B (tidal irrigation is possible during spring tides in the wet season) of tidal lowland hydro-topographical conditions.