Artificial groundwater recharge in Stockholm II. Column test design and tracer tests

Abstract This study was an investigation of the need for pre-treatment of a new raw water source for artificial groundwater recharge. The study was done through a column test, well sampling and survey data relating to 11 artificial recharge plants in Sweden. The column test showed that only 30% of the natural organic matter (NOM) was removed from the new raw water source during infiltration. The survey revealed that the new water source's quality was within the range requiring pre-treatment prior to infiltration. The well sampling results showed a significant correlation between the NOM-content in the raw and treated waters for WTPs without pre-treatment (r = 0.78 and ρ = 0.04), indicating one of the short-term limitations of artificial recharge. The study results indicate that the new raw water source is unsuitable for direct use in artificial recharge and that treatment is required prior to infiltration.

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Investigating artificial groundwater recharge to ensure the water supply to the city of Graz

Water Practice & Technology ◽

10.2166/wpt.2008.063 ◽

2008 ◽

Vol 3 (3) ◽

Cited By ~ 1

Author(s):

Wilhelm Tischendorf ◽

Hans Kupfersberger ◽

Christian Schilling ◽

Oliver Gabriel

Keyword(s):

Water Supply ◽

Groundwater Recharge ◽

Water Demand ◽

Bulk Water ◽

Retention Rates ◽

Subsurface Water ◽

Artificial Groundwater Recharge ◽

Advantages And Disadvantages ◽

Water Recharge ◽

Water Supply Company

Being Austria's fourth largest water-supply company, the Grazer Stadtwerke AG., has ensured the successful water-supply of the Styrian capital with 250.000 inhabitants for many years. The average daily water demand of the area amounts to about 50,000 m3. Approximately 30 % of the total demand is covered by the bulk water supply from the Zentral Wasser Versorgung Hochschwab Süd. The waterworks Friesach and Andritz, which cover the additional 70 % of the water demand, operate by means of artificial groundwater recharge plants where horizontal filter wells serve as drawing shafts. The groundwater recharge systems serve to increase the productivity of the aquifer and to reduce the share of the infiltration from the Mur River. Protection areas have been identified to ensure that the water quality of the aquifer stay at optimal levels. The protection areas are divided into zones indicating various restrictions for usage and planning. Two respective streams serve as the source for the water recharge plants. Different infiltration systems are utilised. Each of the various artificial groundwater recharge systems displays specific advantages and disadvantages in terms of operation as well as maintenance. In order to secure a sustainable drinking water supply the recharge capacity will be increased. Within an experimental setting different mixtures of top soils are investigated with respect to infiltration and retention rates and compared to the characteristics of the existing basins. It can be shown that the current operating sand basin with more than 90% grains in the range between 0.063 and 6.3 mm represents the best combination of infiltration and retention rates. In future experiments the performance of alternative grain size distributions as well as planting the top soil will be tested. Additionally, in order to optimize the additional groundwater recharge structures the composition of the subsurface water regarding its origin is statistically analyzed.

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