Summary Report No. 114
M. Simon (September 2009)
East Germany is marked by a low annual mean height of precipitation of 607 mm. In rain-shadow areas, especially those of the Harz Mountains and the Thuringian Forest, the river basins of Saale and middle Elbe belong to the least precipitated areas in Germany with a height of precipitation from 430 to 500 mm. In East Germany, the mean climatic water deficiencies during the vegetation period amount to 116 mm, in dry years even to 268 mm. This unfavourable precipitation supply, in combination with a high proportion of sandy soils, caused serious uncertainties in harvests on a good portion of the agricultural areas. High variations in yields with a considerable loss of earnings were a vital reason for the relatively high proportion of irrigation in the GDR. Moreover, the agricultural policy of the GDR aimed at self supply as far as possible. Therefore, additional irrigation was strongly enhanced in the area of the present-day east-German states in order to secure and to absolutely increase yields.
Starting with a description of the precipitation conditions and the associated discharge conditions, the development of irrigation in East Germany between 1960 and 1990 is depicted both at large and segmentedly for the administrative districts existing at that time. Sprinkle irrigation and backwater irrigation are discussed separately.
In 1989, irrigation spread to an area of 536,000 ha, this was 8.7 % of the agricultural area. Backwater irrigation summed up to 615,000 ha and 9.9 % respectively. Altogether, 1.151,000 ha (18.6 %) of the agricultural area were irrigated in 1989.
The percentage of sprinkle-irrigation systems larger than 750 ha was 39 % in 1989. Among these were 36 systems with an area larger than 2,000 ha. The percentages of the several irrigation modes in the irrigated area were 80 % in clear water (surface or ground water), 10 % in municipal wastewater, and 10 % as well in clear water-slurry irrigation. 80 % of the irrigation machines in use were rollable sprinklers, 10 % manually relocatable flank sprinklers, 7 % circular sprinklers, and 3 % stationary systems.
The water demand for sprinkle and backwater irrigation, leaving its mark mainly as a loss in the water balance, amounted to 1.76 billion during the vegetation period in 1989, and represented 21 % of the total water demand by all consumer groups in the GDR. Hence, water supply was only safeguarded by huge water transfers and from damreservoirs, water storages and barrages. Due to discharged municipal and industrial waste water having insufficiently been cleaned, and due to insufficient capacities for slurry and silo-seepage piling, the water supply in many river basins was only restrictedly secure.
The development of irrigation (125,000 ha) in the former county of Magdeburg, having been one of the most important agricultural regions of the GDR, was represented in detail. The percentage of sprinkle irrigation was 61,500 ha. The material and financial efforts to install sprinkle-irrigation complexes are depicted in six large sprinkle-irrigation systems and one river basin.
Furthermore, another seven large sprinkle-irrigation systems from outside the former county of Magdeburg were presented in detail, and the water supply from the river Elbe by water transfer ducts was separately described. Due to numerous tables, photos and survey maps, the text is well legible, and the irrigation development can be followed.
Finally, the development of irrigation in the old and the new federal states until 1990 and after was compared. The changes in agricultural policy in East Germany from 1990 on led to a decrease of the irrigation area from 536,000 in 1989 to just under 18 % in 2002.
The increasing demand for agricultural products, as well as regional climate change, will certainly lead to a growing interest in irrigation in East Germany in the future. The historical description of the development of additional irrigation may possibly provide regional adaptation chances.
Therefore, suggestions to extend irrigation were finally submitted.
Complete Document (7,9 MB)