KAZALCI OKOLJA

Key message
Neutral

Total renewable groundwater quantity in the shallow aquifers of Slovenia in the hydrological year 2016 was below the long-term average for the 30-year period 1981–2010.


This indicator is expressed as annual groundwater recharge of shallow aquifers in a hydrological year (1 November–31 October) in all groundwater bodies for the entire territory of the Republic of Slovenia.

Groundwater is replenished by aquifer recharge, which is a complex process of water inflow into the subterranean saturated zone. Recharge is assessed by the regional water balance model and expressed as the height of water infiltrated into aquifers (mm) or the annual variability index (the 1981–2010 average = 100).

 


Charts

Figure VD15-1: Assessment of shallow aquifer recharge in hydrological year 2016 by GROWA-SI model
Sources:

Regional water balance model GROWA-SI (Forschungszentrum JÜLICH, Slovenian Environment Agency), 2017

Figure VD15-2: Groundwater recharge of shallow aquifers - annual quantity deviations from 1981 - 2010 average
Sources:

Regional water balance model GROWA-SI (FZ JÜLICH, Slovenian Environment Agency), 2017

Show data
hydrological year (1 Nov - 31 Oct) 1971 1972 1973 1974 1975 1976 1977 1978 1979 1980
annual average mm 229 385 269 321 309 310 308 312 385 348
deviation (mm) mm -60 96 -20 32 20 21 19 23 96 59
deviation (%) % -21 33 -7 11 7 7 7 8 33 21
period average 1981-2010 mm 289 289 289 289 289 289 289 289 289 289
hydrological year (1 Nov - 31 Oct) 1981 1982 1983 1984 1985 1986 1987 1988 1989 1990
annual average mm 266 326 207 335 327 277 340 252 270 311
deviation (mm) mm -23 37 -82 46 38 -12 51 -37 -19 22
deviation (%) % -8 13 -28 16 13 -4 18 -13 -7 8
period average 1981-2010 mm 289 289 289 289 289 289 289 289 289 289
hydrological year (1 Nov - 31 Oct) 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000
annual average mm 302 303 256 276 335 339 253 300 314 308
deviation (mm) mm 13 14 -33 -13 46 50 -36 11 25 19
deviation (%) % 4 5 -11 -5 16 17 -12 4 9 6
period average 1981-2010 mm 289 289 289 289 289 289 289 289 289 289
hydrological year (1 Nov - 31 Oct) 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010
annual average mm 273 277 184 337 282 222 243 340 321 400
deviation (mm) mm -16 -12 -105 48 -7 -67 -46 51 32 111
deviation (%) % -6 -4 -36 17 -2 -23 -16 18 11 38
period average 1981-2010 mm 289 289 289 289 289 289 289 289 289 289
hydrological year (1 Nov - 31 Oct) 2011 2012 2013 2014 2015 2016
annual average mm 174 207 333 461 301 263
deviation (mm) mm -115 -82 44 172 12 -26
deviation (%) % -40 -28 15 60 4 -9
period average 1981-2010 mm 289 289 289 289 289 289
Figure VD15-3: Groundwater recharge of shallow aquifers - annual quantity deviations in 2016 from 1981 - 2010 average
Sources:

Regionalni vodno-bilančni model GROWA-SI (FZ JÜLICH & Agencija RS za okolje), 2017


Goals

Groundwater is traditionally the major source of drinking water in Slovenia, contributing most of the required quantities in the country. Slovenian groundwater sources exhibit high regional and seasonal variability and, lately, there has been a tendency toward more frequent and more pronounced extremes. As water supply crises can be expected in the future, this indicator is gaining importance. The main benefits of the methods used in the development of this indicator, as well as the benefits of the indicator itself, are as follows:

·         improvement of groundwater quantity assessment, as well as forecasting and alarming in case of hydrological extremes, e.g. hydrological drought in aquifers;

·         identification of groundwater areas prone to frequent hydrological droughts;

·         improvement of groundwater management in the fields of drinking water supply and conservation of groundwater-dependent aquatic ecosystems.


The lowest recharged quantities as well as the highest variability in year-to-year groundwater recharge in shallow aquifers were recorded in groundwater bodies of northeastern Slovenia (Figure VD15-1). In the recent decade, the average recharge of aquifers in the Goričko region was 10-times lower than that of aquifers in the Julian Alps. Apart from this highly pronounced spatial variability, great variability over the course of time was recorded in the recent decade. Compared to the average for the 1981–2010 period, the index of annual groundwater recharge shows great variability, indicating high sensitivity of shallow aquifers in terms of groundwater quantity.

In the hydrological year of 2016, the total rechargeable groundwater quantity in shallow aquifers of Slovenia was markedly below the 1981–2010 average (Figure VD15-2). In the hydrological year of 2016, the highest deviation from the 1981–2010 average was recorded in the groundwater bodies of the Mura basin and in the eastern part of Slovenske Gorice. In other areas, almost no deviations were detected.


Methodology

Date of data source summarization

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