Vízügyi Közlemények, 1987 (69. évfolyam)

3. füzet - Gábri Mihály: Vízügyi-mezőgazdasági tapasztalatok Kambodzsában

482 Gábri Mihály The greatest river is the Mekong (Fig. 4). Its floodwaters inundate the fiats from May till October. The water regime of River Mekong is presented in Fig. 5. Lake Tonlé Sap (with a water surface of 2570 km

2) - which is a sweetwater lake - is normally supplied by its inflowing rivers and by the floodwaters of the Mekong River. Over the flood-area of River Tonlé Sap the silt - deposited by the floods - increased the production in agriculture (Fig. 6). A good - but also rare - example to protect the soil was found at Prey Nop, where about 120 km

2 rice crop has been protected from the inundations of the tide-waters of the sea by a dike-system, 189 km long. (See Fig. I). Then, the problems of rice-production and its water demand were discussed by the author (Tables I and II). Industry of the area in also agriculturally oriented: rice-mills, liquor factories, food and canned food industry, textile, timber-mills, tobacco factory, rubber industry, match factory. Afterwards, the Barai Occidental Irrigation System (Fig. I

) was introduced by the author. The system was initiated about 1000 years ago, in the vicinity of Siemreap. The reservoir of Phnom Norea and its irrigation subsystem were planned by Hungarian experts in 1965. Their report recommended to collect precipitation in the reservoir and then redistribute its waters in the system. The reservoir volume was 15 000 m

3 and the irrigated plots were 50 and 60 km

2. The irrigation system and the reservoir of Prek Thnot (Figs. 15 and 16) were constructed in 1962 with a useful volume of 670 million m

3, with a power production of 2 x 9000 kW, and with an irrigated area of 900 km

2. An irrigation system built in 1958 solved the water supply of 60 km

2 of rice in three blocks (Fig. 14), by use of two springs - with capacities of 1.0 and 1.3 m

3/s - and with a 5 km-long upstream canal (Fig. 13). Reconstruction of some old reservoirs and of the original system were planned in 1932-33 and executed from 1937 till 1959 (Fig. 8). The waters of River Siemreap were conducted into the reservoir of Barai Occidental (with a capacity of 56 million m

3) via a dam (Fig. 9) and by an upstream canal from where the system is reached with an area of 130 km

2 (Figs. 10 and 11). The system has had an experimental station for crop production and animal husbandry. Prallel to the reconstruction of Barai Occidental, the Prey Chhor Irrigation System (Fig. 12) was finalized. It was planned and constructed by the Division de Génie Rural of Cambodia. * * * Les expériences hydroagricoles au Cambodge par G A BRI M. ingénieur de génie civil L'auteur a étudié sur place les conditions hydroagricoles du Cambodge. La partie centrale plate du Cambodge (Fig. 1.) est entourée presque complètement par les montagnes, et á l'Ouest la mer constitute la frontière naturelle. Son climat est subtropical. Les caractéristiques du régime métérorologique sont représentées sur les Figures 2. et 3. Dans les études de l'aménagement des eaux, les intensités de l'évaporation mensuelle sont les suivantes: 100 mm/mois valable à partir du novembre à juin, et 70 mm/mois à partir de juillet à octobre. Le fleuve le plus important est le Mekong (Fig. 4.) dont les crues inondent les zones plates de mai à octobre. Le régime des eaux du fleuve Mékong est représenté sur la Figure 5. Le lac Tonlé Sap d'eau douce de 2570 km

2 est alimenté non seulement par les rivières, mais aussi par les crues du Mekong. Les champs d'inondation de la rivière Tonlé Sap sont remblayés par les apports solides qui favorise la production agricole (Fig. 6.). La protection des sols et des terres agricoles est convenable, mais elle est rarement appliquée. Par exemple: à Prey Nop un endiguement circulaire de 189 km protège une zone der riziculture de 120 km

2 contre les inondations des marées hautes ( Fig. 1.). L'auteur traite plus en détaille les questions de la riziculture, ainsi que sa demande en eau (Tableaux de I. á II.). L'agriculture détérmine également l'industrie du pays: traitement du riz, fabrication de l'alcool, l'industrie de l'alimentation, les conserveries, l'industrie textile, l'usine de fabrication des cigarettes, l'industrie de caoutchouc, l'usine de fabrication de l'allumette.