urban lysimeter union · 2016-11-25 · 5 The completed urban lysimeter was equipped with a UMS environmental monitoring system. UMS supplied the lysimeter with sensors, a data recording

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URBAN LYSIMETER STATION AT THE UNION BREWERY PIVOVARNA UNION D.D. PIVOVARNIŠKA ULICA 02 1000 LJUBLJANA www.pivo-union.si chapter 1: Project of the lysimeter station Andrej Juren, Melhior Pregl chapter 2: Measurements of physical parameters Barbara Čenčur Curk chapter 3: Results of the sampling in suction cups Branka Trček Lysimeter research Group Prepared for the lysimeter excursion/hydrological excursion April 2-5, 2006 3rd day – April 4, 2006, 11.30 AM – 14.30 PM - 11.30 visit of the Union Urban Lysimeter Station - 12.30 visit of the Brewery Museum - 13.00 beer and/or soft drinks tasting and tipical meal offered by the Union Brewery - 14.30 departure to Styria March 2006

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chapter 1

Project of the lysimeter

Andrej Juren1, Melhior Pregl2

1 GeoSi d.o.o. Geological Institute, Kebetova 24, SI-1000 Ljubljana, Slovenia, [email protected]

2IRGO Institute for Mining, Geotechnology and Environment, Slovenčeva 93, SI-1000 Slovenia, [email protected]

Summary from: Juren, A., Pregl, M., Veselič, M. 2003: Project of an urban lysimeter at the Union Brewery, Ljubljana, Slovenia.- RMZ – Materials and Geoenvironment, Vol. 50, No.1 pp. 153-156 Juren, A., Pregl, M., Veselič, M. 2003: Project of an urban lysimeter at the Union Brewery, Ljubljana, Slovenia.-1st International Conference on GROUNDWATER IN GEOLOGICAL ENGINEERING, 22-26 September 2003, Bled, Slovenia, proceedings on CD, 2003, 9 pages An urban lysimeter was constructed to measure infiltration parameters within a Pleistocene alluvial gravel aquifer in a highly urbanized and industrialized environment. Photographs of the execution of the boreholes, an example of the detailed construction drawings, a sketch of the installed probes and a geological cross-section are presented. The basic idea was to construct an urban lysimeter and to measure infiltration parameters within a Pleistocene alluvial gravel aquifer in a highly urbanized and industrialized environment. The lysimeter station is located at Union Brewery in Ljubljana (Figure 1).

Figure 1: Location of the Urban Lysimeter. Boreholes were drilled on the left and right side of the 8,5m deep construction, which has walls reinforced with jet grouting. The jets caused barriers for drilling, so it was necessary to make precise geodetic measurements in order to be able to project boreholes which could meet our demands.

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Figure 2: Drilling of the boreholes

Results and discussion 42 boreholes with lengths from 6 to 8 m were drilled (Figure 2) at 0.30, 0.60, 1.20, 1.80, 3.00 and 4.00 m depths (measured from the bottom of a 0.66 m thick railway gravel bed, therefore from the initial ground surface). A further six boreholes were drilled under an asphalt surface at depths of 0.60, 1.20 and 1.80 m . Under the railway track (a seldom used industrial track) six boreholes were drilled at each depth - three for water sampling and three for measurements of physical parameters. Under the asphalt surface only two boreholes were drilled at each of three depths - one for combined sampling/measurements and one for measurements only (Figure 3).

Figure 3: Boreholes on the left and right side.

As an example the right upper level line RI is demonstrated in Figure 4. The projection of a series of six boreholes (RI/1-6) is illustrated.

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Figure 4: Example of the construction: the upper right level boreholes RI/1-6.

Before the installation of the probes, the geodetic measurements were repeated to determine the precise position of each measuring or sampling point. The comparison between the projected (A) and real length (B), inclination and direction of the upper level boreholes RI/1-6 are shown in Table 1. This demonstrates that with an appropriate drilling technique, permanent work supervision and most importantly, an exact setting of the drilling unit inclination and direction, it is possible to realize the very precise net of sampling and measurement points, even when boreholes are 6-9 m long. Table 1: Comparison between projected and real lengths, inclinations and directions of the

upper level boreholes RI/1-6. 1 2 3 4 5 6

right side A B A B A B A B A B A B

length (mm) 6869 7111 6579 6563 6329 6251 6259 6315 6375 6510 6631 6755

inclination ( º) 2,8 4,0 3,0 2,8 3,1 3,2 3,1 4,2 3,1 3,1 2,9 3,1R I

direction ( º) 18,0 18,0 13,0 15,0 3,0 4,5 -7,0 -6,0 -16,0 -15,8 -25,0 -22,5

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The completed urban lysimeter was equipped with a UMS environmental monitoring system. UMS supplied the lysimeter with sensors, a data recording system and a sampling system. As indicated in Table 2, on the right side of the lysimeter each column is equipped with a single type of measuring probe: tensiometers, TDR probes or suction cups. On the left side of the lysimeter three positions contain a twin probe assembly consisting of a tensiometer probe and a suction cup. Table 2: Position of measuring probes installed in the lysimeter measuring boreholes.

right side 1 2 3 4 5 6 0,3 R I 0,6 R II 1,2 R III 1,8 R IV 3,0 R V 4,0 R VI

left side 6 5 4 3 2 1

0,6 L I 1,2 L II 1,8 L III

Legend:

- installed tensiometers 0,3, 0,6,… 4,0 - depth from the ground - installed TDR probes R I/1,... L III/6 - probes - installed suction cups

Figure 5: Equipped urban lysimeter.

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The construction of the urban lysimeter, which has already been fully equipped (Figure 5), was the first step to the recognition of the role and behaviour of the upper unsaturated groundwater zone in the alluvial gravel aquifer in the highly urbanized environment. The detailed geological cross-section at the end of the boreholes on the right side of the lysimeter, together with the scheme of the measurement and sampling points, will be very useful for interpretation of the data acquired within the foreseen short and long term monitoring (Figure 6).

Figure 6: Geological cross-section on the right side of the lysimeter at the end of the boreholes,

with scheme of measurement and sampling points.

The construction and equipment was jointly financed by Union Brewery, the Ministry of Education, Science and Sports of the Republic of Slovenia, and through the European Commission Project “AISUWRS” - Assessing and Improving Sustainability of Urban Water Resources and Systems.

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chapter 2

Measurements of physical parameters

Barbara Čenčur Curk

IRGO Institute for Mining, Geotechnology and Environment, Slovenčeva 93, SI-1000 Slovenia [email protected]

Summary from: Čenčur Curk, B., Pregl, M., Moon, B. 2005: Establishing an urban lysimeter at the Union Brewery, Ljubljana, Slovenia.- In: Marold, B. & Poppelbaum, C. (eds.): Lysimetrie im Netzwerk der Dynamik von Ökosystemen: Bericht über die 11. Lysimetertagung, am 5. und 6. April 2005 an der HBLFA Raumberg-Gumpenstein, (Bericht - BAL, 2005). Irdning: Höhere Bundeslehr- und Forschunganstalt für Landwirtschaft Raumberg-Gumpenstein, cop. 2005, p.149-150. Soil moisture and capillary pressure are measured continuously. Capillary pressure values in tensiometers on the right side, in position 6 (Ri/6, i=I-VI, see Figure 6) are presented in Figure 7. The highest reaction to precipitation was observed in layers II-IV, which are positioned in clayey- silt (see Figure 6; depth 0,6 and 1 m). There is only a very small reaction to precipitation in the other three probes, since they are positioned in gravel. On the other hand, TDR probes show a rise of moisture after each precipitation event (Figure 7).

Figure 7: Capillary pressure values in measuring points Ri/6 (i=I-VI, see Figure 6)

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chapter 3

Results of the sampling in suction cups

Branka Trček

Geological Survey of Slovenia, Dimičeva 14, SI-1000 Ljubljana, Slovenia [email protected]

Summary from: Trček, B., Juren, A. 2005: Hydrogeological investigations at an urban area of Union Brewery, Ljubljana, Slovenia.- In: Eriksson, E., Genc-Fuhrman, H., Vollertsen., J., Ledin, A., Hvitved-Jacobsen, T.,Mikkelsen, P.S. (eds.): 10th International Conference on Urban Drainage, 21-26 August 2005, Copenhagen, Denmark. Copenhagen: proceedings on CD, 2005, 8 pages. Monitoring of flow and solute transport processes in the lysimeter commenced in June 2003. During the first year of research, continuous measurement of water balance and of physico-chemical water parameters (pH and electroconductivity) were carried out to obtain basic information on the study area. In addition, monthly water sampling for analysis of the 18O and 2H isotopic composition was undertaken to obtain additional information about mixing processes and groundwater residence times in the unsaturated zone. Groundwater was sampled with suction cups. A total of 18 sampling points were established on the right side of the lyimeter: RI-1 to RI-3, RII-1 to RII-3, etc. (Figure 6), whereas on the left side of the lysimeter only 3 sampling points were established: LI-4, LII-5 and LIII-6. In addition, precipitation was sampled near the entrance to the lysimeter. The water balance for the lysimeter sampling points during the first phase of the research is presented in Table 3. There is an absence of data for sampling points RIII-2 and RIII-3 for the first part of the monitoring period, because a proper measuring system was only established in April 2004. Nevertheless, it can be observed in Table 3 that these two sampling points discharged the highest volumes, and that on both, the right and left side of the lysimeter, the bulk of the water is discharged to sampling points on level III. It is important to note that a low discharge occurs under the asphalt surface (LIII-6, since none of the other sampling points did yield any drainage water at that period).

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Table 3: Water balance of lysimeter sampling points

Figure 6 illustrates that the sampling points on level III are located near the contact between two structurally different layers: silty-sandy gravel and underlying clayey silty-sandy silt with gravel grains. The hydraulic conductivity of the upper layer is higher than that of the lower layer. Therefore it is presumed that the greater volumes discharged from level III result from the development of a lateral flow component. Figures 9 and 10 demonstrate that the discharges of level III are strongly dependent on precipitation levels and intensity. Figure 10 also indicates the occurrence of vertical flow from level III, which results in increased volume of discharge from sampling points at the lower levels, particularly from RIV-2 (Oct. 2003, Apr. and Jun. 2004). Statistical characteristics of the electroconductivity of sampled water are presented in the form of boxplots range from 180 to 615 µS/cm (Figure 11). Significantly higher values were recorded on the left side of the lysimeter - up to 4000 µS/cm. These most probably result from winter contamination. Lowest electroconductivity values in the lysimeter are connected with levels I and II (Figures 11 and 12), whereas highest values are connected with level III (Figures 11 and 12), not with lower levels, which reflects the important role of the lateral flow component near this level. On the other hand, Figure 12 also illustrates when and where the vertical flow component dominated. Vertical breakthrough of water from level III into level IV is particularly highlighted for April 04. Boxplots of the 18O isotopic composition of sampled water (precipitation and groundwater) are presented in Figure 13. Precipitation values range between –4.1 and –15.2 ‰ with a mean value of –8.9 ‰. Groundwater values vary between –4.5 and –14.7 ‰, whilst the means of single sampling points are between –8 and –10.7 ‰. The means that as well as the spread of δ18O for the various lysimeter sampling points differ significantly. These differences most probably reflect different residence times of the seepage water. Comparison with precipitation indicates that the ranges of groundwater for the upper two levels (I, II and III) are highest, reflecting the intensive groundwater

Volume (ml) Vol.(mm)

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LIII 6

Precipi- tation

10.7.03 280 340 86 41 70 19 455 110 45 160 5 57.7 27.8.03 385 490 38 45 95 38 370 45 65 38 71.6 17.9.03 175 175 21 20 50 220 40 38 44.5 16.10.03 380 200 110 24 890 29 190 100 24 40 37 110.7 12.11.03 190 180 100 20 60 55 180 20 30 121.4 9.12.03 190 60 20 60 120 20 73.8 20.1.04 280 20 80 90 150.3 17.2.04 180 10 35 20 48 25 27 7 7 10 12.7 25.3.04 230 30 190 50 40 35 20 122.5 15.4.04 420 110 49936 620 75580 40 25 94.3 12.5.04 190 23 25 27 79590 40 20 92550 20 35 5 64.8 15.6.04 520 10 30 20 76880 510 110 136210 50 20 30 25 83.1 13.7.04 210 40 100 20 81140 50 150 125330 30 30 15 133.0 11.8.04 220 25 80 22 89320 70 132530 70 50 20 89.2

total volume 3420 1485 825 237 2573 141 1820 372 241 375 185 1007.4

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dynamics and short residence times. On the other hand, the range of groundwater values for the lower levels (IV, V and VI) are relatively small, which reflects less intensive dynamics and longer residence times.

Figure 9: Daily discharge collected at lysimeter sampling points RIII-2 and RIII-3 The δ18O characteristics of the sampled water are also illustrated in Figures 14 and 15, which present the parameter time-trends for groundwater of the upper and lower lysimeter levels, respectively. Comparison of δ18O trends in precipitation and groundwater in Figures 14 and 15 demonstrates that variations in this parameter are much more attenuated in the lysimeter lower levels, which probably reflects longer groundwater average residence time. Peak values in both figures indicate vertical flow and solute transport in the aquifer during the main hydrological events, i.e. October 2003 and April 2004. For example, in April 2004, precipitation pushed low δ18O water into the lower lysimeter levels (Figure 15). It is presumed that these values may have resulted from snowmelt. The influences of snowmelt may be observed in the lysimeter upper levels one month earlier (Figure 14). It could be concluded that the results of the first phase of the research at the Union Brewery lysimeter has produced general information on the hydrodynamic functioning of the study area and on solute transport. Synthesis of one-year of monitoring data has revealed the basic characteristics of flow and solute/contaminant transport, since the main flow components, the flow hierarchy and the environmental response to the flow system are all indicated. Two important flow types were identified - lateral and vertical flow. Lateral flow has an important role in the protection of groundwater of the Pleistocene alluvial gravel aquifer. However, the role of vertical flow is quite the opposite, because it is the main factor controlling contaminant transport towards the aquifer saturated zone. Hence, investigation of the occurrence and frequency of rapid recharge events represents one of the main themes of the next research phase. With this regard, the monitoring of chlorides, of heavy metals and of herbicides has been established at the beginning of 2005 and the first tracing test was undertaken at the end of March 2005.

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Figure 11: Boxplots of electroconductivity values for water sampled on the right and left side of the lysimeter beneath the industrial railway tracks and the asphalt surface respectively

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Figure 14: Time-trend plot of δ18O values in water sampled from the lysimeter upper levels

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Figure 15: Time-trend plot of δ18O values in water sampled from the lysimeter lower levels