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Lao People's Democratic Republic
Irrigation and drainage
Evolution of irrigation development
A rough estimate of the irrigation potential for Lao People’s Democratic Republic is 600 000 ha (Table 5). The history of irrigation can be traced back several centuries in the northern mountains, where irrigation systems are based on primitive water intake made by logs, soil and/or stone, and have been managed well by communities. From the 1960s, ‘modern’ irrigation systems with concrete weirs and well-designed canals have been built with technical and financial assistance from foreign donors. Irrigation is classified by region into three types: (i) community-managed gravity irrigation in the northern mountains, with a range of service area from 1 ha to over 300 ha; (ii) pump irrigation in the Vientiane plain; (iii) recently introduced pump irrigation along the Mekong river where most of the plain is flood-prone (FAO, 2002).
In 2005, the total area equipped for irrigation was 310 000 ha (Pheddara, 2007). Irrigation by groundwater covers only 200 ha (Figure 2). In 1995, river diversion was the main source of water for irrigation schemes, particularly the smaller ones, accounting for 83 percent of the total equipped area. Pumping from rivers, which is concentrated in the southern region, accounted for 15 percent, and reservoirs 2 percent. All areas use surface irrigation techniques. In 2000 there were 19 170 irrigation schemes.
The actually irrigated area in the wet season has increased from 138 077 ha in 1995 to 270 742 ha in 2005, while in the dry season the area has increased from 36 282 ha in 1995 to 100 934 ha in 2005 (FAO, 2008). While wet season irrigation is common throughout the country, dry season irrigation is mainly concentrated near major cities. It has been noted that after poor yields during rainy seasons, the irrigated area in the dry season are higher than the average to compensate for the low production of the previous season. In 1995, non-equipped flood recession cropping area was an estimated 231 500 ha.
A typology of irrigation schemes is presented in Table 6. The large-scale and several medium-scale schemes are generally underexploited and face operation and maintenance difficulties. Government policy is to transfer management responsibilities to users, but farmers lack management skills as they have never been involved in scheme and water management.
Another classification of irrigated schemes is by type of management. Some schemes are wholly managed by the farmers themselves, while others receive the assistance of irrigation department services. Pump schemes belong to the latter. More than 80 percent of the gravity irrigated schemes are managed by the farmers themselves.
A major irrigation scheme is the community-managed irrigation sector project (CMISP), funded by the ADB, which is to improve more than 40 existing irrigation schemes in the central and northern regions. The communities are responsible for managing the improved facilities by organizing water user associations (WUAs). Other similar schemes are the decentralized irrigation development and management sector project (DIDMP), funded by ADB and France, and the agricultural development project (ADP), funded by the World Bank. DIDMP is a pilot project exercising the irrigation management transfer process, focusing on pump irrigation schemes in six selected provinces. ADP, covering four southern provinces, is a rural development project including not only improvement of irrigation systems but also market oriented community development using village investment funds.
Role of irrigation in agricultural production, the economy and society
In 2005, total harvested irrigated cropped area was an estimated 371 676 ha, of which 270 742 ha in the wet season and 100 934 ha in the dry season. The major irrigated crops are rice, which account for 310 676 ha (245 676 ha in the wet season and 65 000 ha in the dry season), vegetables 33 000 ha, cotton 8 000 ha, citrus 15 000 ha and sugarcane 5 000 ha (Table 5 and Figure 3).
The country also has a large area of non-irrigated rice cultivation (estimated as 450 000 ha in 1994), of which about half is estimated to be upland rice (shifting cultivation), and the other half lowland flooded rice on the alluvial plains (Table 5).
In 1999, the average cost of small-scale weir scheme development was about US$200-400/ha. Large schemes implemented by the government, sometimes with external aid, cost between US$3 500 and 7 000/ha.
Status and evolution of drainage systems
Drainage and flood protection structures have generally been considered in the irrigated schemes design plan but have often not been implemented because of budget restrictions.