Alternating use of aquifers for withdrawal and storage of water for irrigation Joachim Quast 1, Volker Ehlert 2, Hilmar Messal 3, Andreas Muskolus 4

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1 Alternating use of aquifers for withdrawal and storage of water for irrigation Joachim Quast 1, Volker Ehlert 2, Hilmar Messal 3, Andreas Muskolus 4 1 IAMARIS e. V. Applied Water Research, Hamburg, WG Müncheberg, Germany, jquast@zalf.de 2 Institute of Landscape Hydrology, ZALF, Müncheberg, Germany, vehlert@zalf.de 3 Institute of Hydrology, Christian Albrecht University, Kiel, Germany, hmessal@hydrology.uni kiel.de 4 IASP, Humboldt Universität zu Berlin, Germany, andreas.muskolus@agrar.hu berlin.de Introduction Actual problems in water supply for agricultural irrigation in the Berlin Brandenburg Region may be overcome by a concept for an alternating groundwater withdrawal and refilling of the aquifer by infiltration of overrun water in winter or of treated waste water. Besides cost benefit aspects, water availability during summer will become the decisive criterion for the feasibility of irrigation. The previously common withdrawals from low water discharges of streams or from lakes are no longer allowed due to ecological restrictions. Groundwater withdrawals are an alternative when deficits in the aquifer are compensated by artificial infiltration of winterly runoff surpluses or of purified wastewater. Key words: irrigation, groundwater, storage, withdrawal Regional conditions The region Berlin Brandenburg is geomorphologically characterized by sandy and loamysandy ground moraines which are crossed by wetland depressions in the course of glacial valleys. The fen wetlands and many lakes are fed from the groundwater evolved below the sandy infiltration sites within the catchment area. At comparatively low annual rain fall totals of 500 to 600 mm, a groundwater recharge of 100 to 110 mm occurs on these sites. Already at present, the summerly water balance deficit of wetlands and lakes is 300 to 400 mm, which could be compensated only by winterly flooding. In case of lower rainfalls and increased evaporation in future, less groundwater recharge, less feeder flows to the wetlands and an increasing water withdrawal from wetlands and lakes are to be expected. Farming practices Farming on sandy and sandy loamy moraine sites in Brandenburg often experienced reduced yields or crop failures. Therefore, a wide ranging irrigation programme was established during the 1970ties and 1980ties. Irrigation systems were installed on more than 10 % of the farmland. Water was taken from surface waters (rivers and lakes), supplemented by sprinkling of slightly purified manure and wastewater. Groundwater remained reserved to drinking water. Conceptual proposals for an alternating use of aquifers for withdrawal and storage of water for irrigation (Kluge et al., 1980) could not be implemented. Sprinkler irrigation was reduced drastically after 1990 under conditions of market economy and because of caused ecological damages. Meanwhile, there is a revival of irrigation for crops with high economic returns such as vegetables, fruits, or quality potatoes for the food industry. The water is provided from

2 groundwater, which is to be rated as crucial already today. Groundwater levels in Brandenburg have been on a declining trend since years. This results in decreased inflows to wetlands and lakes. The water levels decline, peripheral zones fall dry. Any groundwater withdrawal for irrigation leads to further reductions of discharges to lowlands. A crucial situation due to falling groundwater levels is observed e. g. in a major asparagus growing region southwest of Berlin. Discussion Conclusion An expansion of irrigated agriculture will be possible in future only when water availability is assured with increasing demand due to climate change by means of counter cyclical storage in winter surplus periods and using the purified effluents from sewage treatment plants (Quast & Messal, 2010). A pilot plant is in preparation at an irrigation trial site of the Humboldt Universität zu Berlin. Extraordinary importance is inhered to the future economic use of m 3 of treated wastewater daily produced by the six large treatment plants of Berlin. Large scale contamination of groundwater resources can be excluded by already available models and control strategies. Technical and technological challenges exist with regard to the water supply and efficient infiltration processes. Ultimately the economic viability at probable future conditions is decisive in the foreseeable future. This requires trials in pilot installations with the target to achieve economically practical and applicable solutions by Figure 1: Scheme for alternating groundwater withdrawal for irrigation and recharge by infiltration of winter surplus run off or treated wastewater as storage for the next season References Kluge, W., Quast, J., Kröll, D., (1980). Geohydrologische Besonderheiten bei der Vorbereitung von Grundwasserberegnungsanlagen. Zeitschrift für angewandte Geologie, Berlin, Quast, J. Messal, H. (2010):Grundwasserentnahme für Bewässerung und alternierende Wiederauffüllung des Absenkungstrichters durch Infiltration winterlicher Abflussüberschüsse oder von Klarwasser aus Kläranlagenabläufen, in: Kaiser, K., Libra, J., Merz, B., Bens, O., Hüttl, R.F. (Hrsg.), 2010: Aktuelle Probleme im Wasserhaushalt von Nordostdeutschland: Trends, Ursachen, Lösungen. Scientific Technical Report 10/10. Deutsches GeoForschungsZentrum, Potsdam,

3 Alternating use of aquifers for withdrawal and storage of water for irrigation Joachim Quast Co- authors: Volker Ehlert, Hilmar Messal, Andreas Muskolus

4 Landscape Water Balance in the Berlin-Brandenburg Brandenburg Region P Niedermoor mit Ent- und Bewässerung ΔS R abu Grundwasserleiter Einzugsgebiet E R zuo R abo E R z uu Versickerung Versickerung Grundwasserstauer ΔS = P E + R zuu + R zuo R abu -R abo

5 Agro-hydrological situation in NE-Germany Annual precipitation of mm. Brandenburg is "poor in water" but "rich in waters" Sandy/loamy soils, mm/a GW-recharge Pleistocene aquifers (sand, gravel), good storage capacity, but decreasing groundwater levels, High demand for irrigation. Main problem: Water availability (withdrawal from surface waters not allowed because of danger of environmental defects)

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7 Wasser ist auf vielen Standorten der ertragsbegrenzende Faktor Nr. 1

8 Subsurface Micro-Irrigation of Potatoes Quelle: Netafim Sourell

9 Key data of the agricultural enterprises participating in the Fläming Region Pilot Project on Sprinkler Irrigation of the State of Brandenburg Agricultural enterprise a) total agricult. area b) prepared for irrigation Sprinkler irrigation Systems Annual supplementary irrigation Oehnaland Agrargesellschaft, Oehna 4080 ha 750 ha Center pivot mm Agrar GmbH Flämingland, Blönsdorf 4293 ha 800 ha Center pivot, movable small center pivot mm Agrargenossenschaft Welsickendorf, 1635 ha 500 ha Movable center pivot, hose wheel machines mm

10 Water demand 1 2 Mill.m 3 a -1 Area (blue) developed for sprinkler irrigation (800 ha) of the agricultural enterprise Agrar GmbH Flämingland, Blönsdorf, Brandenburg, 2005

11 Kluge, W.; Quast, J.; Kröll, D. (1980): Geohydrologische Besonderheiten bei der Vorbereitung von Grundwasserverregnungsanlagen. In: Z. für angewandte Geologie.- Berlin: 26 ;

12 Ground Water Storage

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14 Challenges for innovative technical solutions Use of storage capacities of aquifers and their retarded dynamic to improve water availability during irrigation season and to stabilise landscape water balance Infiltration technologies (maintenance) controlled matter migration (monitoring system) Water transfer to infiltration area

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16 Treated water: m 3 d -1 Output for >100000ha irrigation area

17 Conclusions: In the Berlin-Brandenburg region there are no alternatives to alternating use of aquifers for withdrawal and storage of water for irrigation Lack of water and climate change require solid solutions within at least 5 to 10 years Pilot-facilities for research and development must be realised immediately