LANDSCAPE VULNERABILITY OF LJUBLJANA'S MOST IMPORTANT WATER SOURCE
POKRAJINSKA RANLJIVOST NAJPOMEMBNEJ[EGA VODNEGA VIRA
LJUBLJANE
Valentina Brecko Grubar
Ljubljansko polje (photography Valentina Brecko Grubar). Ljubljansko polje (fotografija Valentina Brecko Grubar).
Abstract	UDC: 911:504.05(497.4 Lj.)
628.11:504.05(497.4 Lj.) COBISS: 1.01
Landscape Vulnerability of Ljubljana's Most Important Water Source
KEY WORDS: groundwater, water source, sensitivity of the environment, environmental pollution, landscape vulnerability, Ljubljansko polje, Ljubljana
Situated in the immediate vicinity of the city and in an area with landscape properties advantageous for its regeneration, the groundwater of Ljubljansko polje is the most important source of potable water for the supply of Ljubljana. A humid climate, the intensive infiltration of precipitation and the Sava River through a covering layer of sand and gravel sediments, a large dynamic stock of aquifer, and, in comparison with the majority of groundwaters in Slovenia, the great depth to the water table result in moderate landscape sensitivity or moderate regeneration and neutralization capacities of the water source. Due to the intensive, predominantly urban use of the surface above the groundwater and environmental pollution, Ljubljansko polje and its groundwater are excessively burdened, and the natural self-cleansing capacity of the environment is already diminished. We can therefore justifiably speak of the vulnerability of the environment of the water source to further pollution and about the groundwater as a limiting factor in planning further encroachments in the environment of Ljubljansko polje.
Izvleček	UDC: 911:504.05(497.4 Lj.)
628.11:504.05(497.4 Lj.) COBISS: 1.01
Pokrajinska ranljivost najpomembnej{ega vodnega vira Ljubljane
KLJUCNE BESEDE: podtalnica, vodni vir, občutljivost okolja, obremenjevanje okolja, pokrajinska ranljivost, Ljubljansko polje, Ljubljana
Podtalnica Ljubljanskega polja je najpomembnejši vir pitne vode za oskrbo Ljubljane, ki se nahaja v neposredni bližini mesta in na območju z ugodnimi pokrajinskimi lastnostmi za njegovo obnavljanje. Hu-midno podnebje, intenzivna infiltracija padavin in Save skozi prepustno krovno plast peščeno-prodnatih sedimentov, velika dinamična zaloga vodonosnika ter, v primerjavi z večino podtalnic v Sloveniji, tudi velika globina do gladine podtalnice, pogojujejo zmerno pokrajinsko občutljivost oz. zmerne regenera-cijske in nevtralizacijske sposobnosti okolja vodnega vira. Zaradi intenzivne, pretežno urbane rabe površin nad podtalnico in onesnaženosti okolja pa je Ljubljansko polje s podtalnico prekomerno obremenjeno in so naravne samočistilne sposobnosti okolja že zmanjšane. Zato lahko upravičeno govorimo o ranljivosti okolja vodnega vira za nadaljnje onesnaževanje in o podtalnici kot omejitvenem dejavnik pri načrtovanju posegov v okolje Ljubljanskega polja.
The editorialship received this paper for publishing in July 5th 1999. Prispevek je prispel v uredništvo 5.7.1999.
Contents - Vsebina
1.	Introduction	55
2.	Methodology for the study of the vulnerability	
	of the environment	55
3.	Results of the quantitative and qualitative analysis of the	
	environment of Ljubljana's most important water source	57
3.1.	Functional evaluation of the natural and geographical	
	indicators of the environment	57
3.2.	Functional evaluation of the sociogeographical indicators	
	of the environment	59
4.	Evaluation of landscape characteristics of the environment	
	of the most important water source of Ljubljansko polje	64
4.1.	Assessment of self-cleansing (regeneration and neutralization)	
	capacities of the environment of the water source	64
4.2.	Evaluation of the total environmental pollution	
	of the water source	67
4.3.	Assessment of the still acceptable environmental pollution	
	of Ljubljana's most important water source	72
4.4.	Total evaluation of vulnerability and proposal for the level	
	of protection for the environment of the water source	73
5.	Conclusion and discussion	76
6.	Bibliography	77
7.	Summary in Slovene - Povzetek	78
Address - Naslov:
Valentina Brecko Grubar, M. Sc.
Oddelek za geografijo, Filozofska fakulteta Aškerčeva 2 1000 Ljubljana Slovenija
Phone - telefon: +386 (0)61 2411242
Fax - faks: +386 (0)61 1259 337
E-mail - el. pošta: Valentina.Brecko@FF.Uni-Lj.si
1. Introduction
The contribution »Landscape Vulnerability of Ljubljana's Most Important Water Source« is part of a more extensive research project in which we studied the influence of landscape and ecological factors on the regeneration of Ljubljana's most important water source (Bre~ko, 1998). For the supply of the capital of Slovenia with potable water - annual use exceeds 25 million m3 - and due to the substantial losses in the piping system, it is necessary to ensure at least 50 million m3. The water source that provides 90% of the potable water is the groundwater of Ljubljansko polje. It occurs in the sand and gravel sediments of the Sava River below the northern part of the city and its outskirts. The area of immediate infiltration of precipitation measures about 80 km2 and receives an average of 1400 mm of precipitation per year. Somewhat less than half of the total quantity evaporates, and the rest is for the most part included in the regeneration of the groundwater, the dynamic supply of which is estimated at 3 m3/s, while the total quantity of the water in the aquifer exceeds 100 million m3 (Breznik, Brilly, 1981). The dynamic supply of the Ljubljansko polje aquifer represents 15% of all the researched supply of underground water in aquifers with inter-granular porosity and 6% of all reserves of underground water in Slovenia. Other groundwaters and springs occur in the wider surroundings of Ljubljana, but due to its proximity to users, the Ljubljansko polje water source is of exceptional importance and has provided potable water since the beginning of the construction of the waterworks system in 1898. The groundwater of Ljubljansko polje is still considered a qualitative source, although the results of analyses indicate the increasing influence of environmental pollution.
2. Methodology for the study of the vulnerability of the environment
The study of the vulnerability of the environment includes an analysis of the properties of landscape-forming elements of individual landscape and ecological units relative to their neutralization and regeneration capacity and a study of their pollution tolerance (Plut, 1995). Articles 51 and 52 of the Law on the Protection of the Environment define the undertaking of studies on the vulnerability of the environment in Slovenia. »In planning human activities that encroach on the environment, the law introduces three instruments to harmonize such encroachments to the highest possible degree with fundamental principles and requirements for the protection of the environment« (Law on the Protection ..., 1994). Those instruments include the vulnerability of the environment, the level of environmental protection based on environmental vulnerability, and comprehensive assessments of influences on the environment. The consideration of vulnerability in planning encroachments on the environment is regulated under Article 51 as a general obligation. The draft of the methodology for the study of the vulnerability of the environment was elaborated with colleagues at the Institute of Geography in 1996 and represents the technical basis for the preparation of regulatory acts. The methodology was completed on the basis of sample studies on the vulnerability of the environment undertaken for several municipalities where the following landscape elements were treated: relief and lithology, air, waters, soil, and forest. In the municipalities of Spodnje Podravje and Prlekija (Bre~ko, Hočevar et al., 1996), groundwaters and the selected indicators for the quantitative and qualitative analysis of the environment relative to groundwater were treated as landscape elements for the first time.
Vulnerability of the environment is the anthropogenically-increased sensitivity of the environment or the changing response of the environment to further human encroachment on the composition and dynamics of the environment. Every activity or encroachment changes the natural environment, the same encroachment can have different influences on the elements, and the vulnerability of the environment is therefore different in its various parts. The most vulnerable are environments with low self-cleansing capacities that are strongly polluted and degraded landscape-wise. With further pollution, the vulnerability of the environment to human encroachment even increases.
The neutralization and regeneration capacity of the environment of the water source is understood as the ability of the environment to mitigate or even annihilate the negative influences of pollution and other human encroachment in the environment of the water source and the tendency toward the restoration of the natural state that was damaged by a particular encroachment in the environment. The self-cleansing (absorption) capacity depends both on the properties of the environment where the water source is found and on the properties of the water, itself a landscape element.
The procedure for evaluating the vulnerability of the environment of the water source encompasses:
•	indicators for the quantitative and qualitative analysis of the environment;
•	evaluation of the regeneration and neutralization capacities of the environment;
•	assessment of the level of total environmental pollution achieved;
•	evaluation of the still acceptable extent of environmental pollution;
•	overall assessment of the vulnerability of the environment and proposal for the level of protection for the environment of the water source.
Quantitative and qualitative analysis encompasses a large number of physical geographical and direct and indirect sociogeographical indicators of the environment that are the basis for the evaluation of self-cleansing capacities and the overall pollution. The evaluation of regeneration and neutralization capacities was achieved by evaluating physical geographical indicators defined with classes and chosen according to our own judgment, and the assessment of the total environmental pollution was achieved by assessment of sociogeographical indicators. The evaluation of the still acceptable extent of the pollution is the result of the balance between the regeneration and neutralization capacity of the environment and its pollution, while the stated evaluations together are the basis for the assessment of the vulnerability and the proposal for the level of the protection of the environment.
Figure 1: Landscape subunits in Ljubljansko polje with groundwater pumping stations for the supply of public waterworks Slika 1: Pokrajinske podenote na Ljubljanskem polju in ~rpali{~a podtalnice za oskrbo javnega vodovoda.
The spatial unit for which the indicators are evaluated and for which the total assessments are defined is the result of the analysis of the characteristics of the landscape factors that decisively influence the sensitivity of the environment of the water source. As priority factors, we considered the depth to the mean level of the water table, the direction of the flow of the groundwater, and the predominant land use. Also helpful to us were the boundaries of the water protection areas for the groundwater pumping stations that were defined considering the hydrological, hydrogeological, and technical conditions for the use of the water source. Ljubljansko polje was divided into ten subunits that differ considerably relative to their size and together cover 81.5 km2. Four subunits are located on the left side of the Sava River between Tacen and Kamniška Bistrica, and the remaining six are located on its right side between Medno and the confluence of the Sava with the Ljubljanica River. We named them after settlements and in one case according to the location of the subunit (Fig. 1)
TABLE 1: LANDSCAPE SUBUNITS IN LJUBLJANSKO POLJE. PREGLEDNICA 1: POKRAJINSKE PODENOTE NA LJUBLJANSKEM POLJU
subunit	Tacen	Jarski	Črnuče	Beričevo	Medno	Kleče	Dravlje	Central	Tomačevo	Polje
	Gameljne	prod	Nadgorica	Brinje	Vižmarje	Roje	Šiška	Ljublj. polje	Hrastje	Zalog
label	1.1.1.	1.1.2.	1.1.3.	1.1.4.	1.2.1.	1.2.2.	1.2.3.	1.2.4.	1.2.5.	1.2.6.
area in km2	4.6	6.9	2.7	3.3	5.7	12.1	4.0	16.7	9.6	16.0
proportion	5.6	8.5	3.3	4.0	7.0	14.8	4.9	20.5	11.8	19.6
type of settlement	suburb	suburb	urban	suburb	suburb	suburb	urban	urban	urban	suburb
primary land use	farming	forest	typical	farming	farming	farming	typical	typical	very	very
			urban				urban	urban	diverse	diverse
pumping station	none	Public	none	none	none	Public	none	industry	Public	industry
		water supply				water supply			water supply	
3. Results of the quantitative and qualitative analysis of the environment of Ljubljana's most important water source
3.1. Functional evaluation of the natural and geographical indicators of the environment
Thickness of aquifer sediments
A larger thickness of aquiferous sediments means a potentially larger dynamic reserve of groundwater. The classes were determined relative to conditions in Slovenia.
Classes:
1.	very thick aquifer - thickness exceeding 20 m;
2.	thick aquifer - thickness from 11m to 20 m;
3.	medium thick aquifer - thickness from 5 m to 10 m;
4.	thin aquifer - thickness of the aquiferous sediments does not exceed 5 m.
subunit	Tacen Gameljne	Jarški prod	Črnuče Nadgorica	Beričevo Brinje	Medno Vižmarje	Kleče Roje	Dravlje Šiška	Central Ljublj. polje	Tomačevo Hrastje	Polje Zalog
class	1.1.1. 4	1.1.2. 1	1.1.3. 3	1.1.4. 1	1.2.1. 2	1.2.2. 1	1.2.3. 2	1.2.4. 1	1.2.5. 1	1.2.6. 2
The self-cleansing capacity of the environment of the water source is greater in larger dynamic reserves and, depending on the porosity of the sediments, increases with the thickness of the aquiferous sediments. The greatest thickness of the Ljubljansko polje aquifer was measured in its central part south of the Sava River at the Kleče pumping station, where it exceeds 70 m; it is more than 60 m thick in the western (influent) section and at Jarški prod on the left bank of the Sava. In the eastern (effluent) section of Ljubljansko polje, the thickness is about 35 m (Breznik, Brilly, 1981).
Depth of the groundwater
A greater depth of the groundwater means potentially better protection from surface environmental pollution since on its way to the groundwater, the percolating polluted water can be cleansed to a large degree. The classes are determined relative to conditions in Slovenia with foreign experience taken into account (Europe's Environment, 1995).
Classes:
1.	very deep groundwater - over 20 m;
2.	deep groundwater - 11m to 20 m;
3.	shallow under the surface - 3 m to 10 m;
4.	very shallow under the surface - below 3 m; in the event of high water levels, these areas are flooded.
subunit	Tacen	Jarški	Črnuče	Beričevo	Medno	Kleče	Dravlje	Central	Tomačevo	Polje
	Gameljne	prod	Nadgorica	Brinje	Vižmarje	Roje	Šiška	Ljublj. polje	Hrastje	Zalog
	1.1.1.	1.1.2.	1.1.3.	1.1.4.	1.2.1.	1.2.2.	1.2.3.	1.2.4.	1.2.5.	1.2.6.
Class	3	3	3	3	2	1	1	1	2	2
The groundwater of Ljubljansko polje ranks among the deeper groundwaters in Slovenia. Its depth in most places exceeds 15m and is greatest in the central part south of the Sava River where it mostly exceeds 20 m and in some places even 30 m. Along the Sava, north of it, and in the eastern (effluent) part of Ljubljansko polje, the depths are mostly below 10 m and 15 m at the most (Hidrološki letopis, 1990-1996).
Influents and the flow of groundwater
In Ljubljansko polje, the regeneration of the dynamic reserve of groundwater is favourable due to plentiful underground and surface influents and a fast flow. These are the consequence of the humidity of the climate, the snow-rain flow regime of the Sava River as the main source of the renewal of the groundwater supply, the large gradient of the underground flow, and the great porosity of the sediments. Influents rich in quantity and the large flow of the groundwater are less favourable for the quality of the ground-water due to the polluted environment. There are favourable conditions in the subunits in the influent section of Ljubljansko polje for greater self-cleansing capacities, but conditions are much worse in the effluent, eastern part due to the numerous potential polluters in the central part of Ljubljansko polje.
Permeability of the covering layer
Permeability is a hydrogeological property of rock that percolates water. It is expressed with a coefficient of filtration. Permeability is good with coefficients larger than 10-5m/s and poor with coefficients from 10~5m/s to 10-9m/s. Impermeability begins with coefficients below 10-9m/s (Ridanović, 1993). Permeability depends on the size of pores and is greatest in gravel and sandy sediments of large granulation that are not agglutinated. A poorer permeability of the covering layer has favourable effects on the self-cleansing capacity of the environment of the water source because it slows down the influence of surface waters and increases the possibilities for the self-cleansing of the polluted influents.
Classes:
1.	poorly permeable covering layer (below 10-5m/s);
2.	consolidated poorly permeable layers found above or between permeable sediments;
3.	permeable covering layer with intermediate unconsolidated poorly permeable layers;
4.	permeable covering layer (above 10-5m/s).
subunit	Tacen Gameljne	Jarski prod	Črnuče Nadgorica	Beričevo Brinje	Medno Vižmarje	Kleče Roje	Dravlje Šiška	Central Ljublj. polje	Tomačevo Hrastje	Polje Zalog
class	1.1.1. 3	1.1.2. 4	1.1.3. 2	1.1.4. 3	1.2.1. 4	1.2.2. 4	1.2.3. 1	1.2.4. 3	1.2.5. 4	1.2.6. 3
Relative to the permeability of the covering layer, the self-cleansing capacity of the environment is unfavourable because in most cases permeable unagglutinated and partially agglutinated fluvioglacial sediments cover the aquifer (Osnovnageološka karta, 1974,1983). The layers of clay-loam sediments occurring between the quite permeable layers in three subunits and covering them completely in two subunits play an important role. The clay sediments were deposited by surface water currents from the river basins at the margin of Ljubljansko polje composed of paleozoic slate claystone and sandstone.
Pedological and vegetation blanket
The soil layer is a relatively thin cover layer and of lesser importance for the self-cleansing capacity of the environment of the water source. It has a more decisive influence on agricultural land use and on the permanent growth of natural vegetation that increases the self-cleansing capacity of the environment.
Classes:
1.	impermeable to poorly permeable soil, greater vegetation cover;
2.	poorly permeable shallow to deep soil, smaller vegetation cover;
3.	permeable medium deep to deep soil, smaller vegetation cover;
4.	permeable shallow soil, smaller vegetation cover.
subunit	Tacen Gameljne	Jarški prod	Črnuče Nadgorica	Beričevo Brinje	Medno Vižmarje	Kleče Roje	Dravlje Šiška	Central Ljublj. polje	Tomačevo Hrastje	Polje Zalog
class	1.1.1. 2	1.1.2. 4	1.1.3. 1	1.1.4. 3	1.2.1. 3	1.2.2. 3	1.2.3. 1,3	1.2.4. 3	1.2.5. 3,4	1.2.6. 3,2
In classifying the subunits into classes relative to the properties of the soil and the vegetation, two classes appear in some cases due to the diversity within the subunits. Most of these stretch from the Sava River to the marginal hills and have a diverse composition of sediments and different water conditions decisive for the development of soil. On the alluvial plain along the Sava are undeveloped fluvial soils on carbonate gravel; loam-clay soils that are frequently gleyed developed on the river fans with clay sediments; and brown soils on carbonate gravel are found on the higher terraces (Pedološka karta, 1966 and 1985). Forest vegetation is greatest on the shallow soils along the Sava and on poorly permeable, moist areas on the edge of Ljubljansko polje.
3.2. Functional evaluation of the sociogeographical indicators of the environment
Population density (inhabitants per km2)
This is the most general indicator of potential environmental pollution. A larger population density means the greater consumption of potable water, a larger quantity of waste water and garbage, denser traffic,
etc. This indicator is especially important where households are not connected to a sewage system or when other indicators of environmental pollution are unavailable.
Classes:
1.	unsettled and sparsely settled (up to 40 inhabitants per km2);
2.	moderate (41-100 inhabitants per km2);
3.	dense (101-500 inhabitants per km2);
4.	very dense (501-1000 inhabitants per km2);
5.	very dense urban (over 1001 inhabitants per km2).
subunit	Tacen Gameljne	Jarski prod	Črnuče Nadgorica	Beričevo Brinje	Medno Vižmarje	Kleče Roje	Dravlje Šiška	Central Ljublj. polje	Tomačevo Hrastje	Polje Zalog
class	1.1.1. 4	1.1.2. 4	1.1.3. 5	1.1.4. 3	1.2.1. 4	1.2.2. 3	1.2.3. 5	1.2.4. 5	1.2.5. 5	1.2.6. 4
The largest population density is in subunits covering the consolidated built-up urban area of Ljubljana in the central part of Ljubljansko polje and in areas of previous suburbanization that are gradually growing with the city. The lowest population density is in the subunit with semi-agrarian settlements in its northeastern part and in the subunit that largely covers the protected area of two groundwater pumping stations northwest of the city. Here, the growth of settlements was already limited in 1955 by the ordinance on the protection of the groundwater.
Connection of households with the sewage system
Connection with the sewage system is ranked among the most important indicators of environmental pollution relative to water. Connection of all users of water with a watertight sewage system would substantially decrease the danger of polluting the water source.
Classes:
1.	75.1% and more households are connected with the sewage system;
2.	50.1% to 75% of the households are connected with the sewage system;
3.	25.1% to 50% of the households are connected with the sewage system;
4.	25% and less households are connected with the sewage system.
subunit	Tacen Gameljne	Jarški prod	Črnuče Nadgorica	Beričevo Brinje	Medno Vižmarje	Kleče Roje	Dravlje Šiška	Central Ljublj. polje	Tomačevo Hrastje	Polje Zalog
class	1.1.1. 4	1.1.2. 2	1.1.3. 1	1.1.4. 4	1.2.1. 4	1.2.2. 1	1.2.3. 1	1.2.4. 1	1.2.5. 1	1.2.6. 2
In the central part of Ljubljansko polje, which to a large extent is covered by consolidated urban buildup, more than 90% of the households are connected with the sewage system, while only a good 50% are connected in its northern and eastern parts. The worst conditions are on the western and northeastern edges where the majority of the households have discharging cesspools. All together, only a good two thirds of the users of water in Ljubljansko polje are connected with the sewage system; the environmental pollution from waste water is therefore considerable.
Proportion of cultivated field area
With the help of the proportion of cultivated field areas, we can only partially evaluate the environmental pollution of the water source due to agricultural production. It depends on the choice of cultures, the method of production, and primarily on the use of fertilizers and pesticides.
Classes:
1.	below 10%;
2.	10 to 25%;
3.	16 to 40%;
4.	above 40%.
subunit	Tacen Gameljne	Jar{ki prod	Crnu~e Nadgorica	Beri~evo Brinje	Medno Vižmarje	Kle~e Roje	Dravlje Si{ka	Central Ljublj. polje	Toma~evo Hrastje	Polje Zalog
class	1.1.1. 2	1.1.2. 2	1.1.3. 1	1.1.4. 3	1.2.1. 2	1.2.2. 3	1.2.3. 1	1.2.4. 1	1.2.5. 3	1.2.6. 3
The largest proportion of cultivated field areas occurred in 1993 in the eastern part of Ljubljansko polje and in the protected areas of the Kle~e, [entvid, and Hrastje pumping stations; the smallest occurred in its central, built-up part. The cultivated field areas are largely devoted to the intensive production of vegetables for the Ljubljana market and to fodder cultures. We therefore presume that agricultural pollution in Ljubljansko polje is considerable.
Proportion of forest
A larger proportion of forest means less pollution and the greater self-cleansing capacity of the environment of the water source and is therefore one of the more important indicators:
Classes:
1.	71 to 100%;
2.	51 to 70%;
3.	31 to 50%;
4.	11 to 30%;
5.	below 11%.
subunit	Tacen Gameljne	Jar{ki prod	Crnu~e Nadgorica	Beri~evo Brinje	Medno Vižmarje	Kle~e Roje	Dravlje Si{ka	Central Ljublj. polje	Toma~evo Hrastje	Polje Zalog
class	1.1.1. 5	1.1.2. 4	1.1.3. 4	1.1.4. 5	1.2.1. 5	1.2.2. 4	1.2.3. 5	1.2.4. 5	1.2.5. 5	1.2.6. 5
In Ljubljansko polje, the total proportion of forest is very small and except along the Sava and on the shallow soils of Jar{ki prod and Tomacevski prod northeast of Ljubljana, there are no larger consolidated forest surface areas. In the majority of the subunits, the proportion of forest is less than 11%, which is unfavourable for the vulnerability of the environment of the water source.
Proportion of built-up surface areas
This indicator is especially important where users of water are not connected to the sewage system and meteorological water from the built-up areas is not captured. Here, various potential polluters of the environment of the water source are to be found, and due to the buildup, the percolation of precipitation into the underground is decreased and the surface outflow is increased.
Classes:
1.	below 10%;
2.	10 to 30%;
3.	31 to 50%;
4.	above 50%.
subunit	Tacen Gameljne	Jarski prod	Črnuče Nadgorica	Beričevo Brinje	Medno Vižmarje	Kleče Roje	Dravlje Šiška	Central Ljublj. polje	Tomačevo Hrastje	Polje Zalog
class	1.1.1. 2	1.1.2. 1	1.1.3. 3	1.1.4. 1	1.2.1. 3	1.2.2. 2	1.2.3. 4	1.2.4. 4	1.2.5. 2	1.2.6. 2
The proportion of built-up surface areas is lowest on the northern and eastern edge of Ljubljansko polje and in the water protection areas of the Kleče and [entvid pumping stations. The highest proportion, above 80%, is found in the central part of Ljubljansko polje.
Traffic Pollution
The number of vehicles daily on individual road sections enables only an estimate of potential traffic environmental pollution of the water source. For a more accurate assessment, it would be necessary to know the composition of the traffic, its dynamics, and the equipment of the vehicles.
Classes:
1.	small - daily traffic on the majority of the roads does not exceed 1000 vehicles;
2.	moderate - daily traffic on the majority of the roads is from 1000 to 3000 vehicles;
3.	large - daily traffic on the majority of the roads is from 3000 to 7000 vehicles;
4.	very large - daily traffic on the majority of the roads exceeds 7000 vehicles.
subunit	Tacen Gameljne	Jarški prod	Črnuče Nadgorica	Beričevo Brinje	Medno Vižmarje	Kleče Roje	Dravlje Šiška	Central Ljublj. polje	Tomačevo Hrastje	Polje Zalog
class	1.1.1. 3	1.1.2. 4	1.1.3. 2	1.1.4. 1	1.2.1. 3	1.2.2. 4	1.2.3. 4	1.2.4. 4	1.2.5. 4	1.2.6. 1
Traffic creates major environmental pollution in the wider area of Ljubljana and in the majority of Ljubljansko polje through the emission of exhaust gasses, and relative to leaching into the groundwater, lead emissions are especially problematic. With the increase of traffic density in recent years, the number of accidents and the risk of spilling hazardous materials into the groundwater has also increased. With the indicator of daily traffic on the majority of roads, we established that traffic pollution is largest in the subunits across which lead the main city roads and bypasses (with more than 40,000 vehicles per day). Because the boundaries of several subunits overlap the routes of the main traffic connections between the city and its surroundings, the traffic pollution from the roads is evident in the evaluations of two neighbouring subunits and is therefore counted twice.
Direct indicators of environmental pollution of the water source
Total quantity of water used by companies
This is an auxiliary indicator that is important when industrial users ofwater are not connected with the sewage system or do not clean their waste water before releasing it into the environment. Because the majority of water used returns to the environment as waste water (which is often specifically polluted), with the aid of the water use indicator we can assess the »contribution« of companies to environmental pollution with waste water.
Classes:
1.	no users of water or a small number of users with very low consumption of water (total up to 10,000 m3 per year);
2.	smaller number of users with low consumption of water (total from 10,000 to 50,000 m3 per year);
3.	larger number of users with moderate total consumption of water or one large user of water (total from 50,000 to 500,000 m3 per year);
4.	large number of users with high consumption of water (total above 500,000m3 per year).
										
subunit	Tacen Gameljne	Jarški prod	Črnuče Nadgorica	Beričevo Brinje	Medno Vižmarje	Kleče Roje	Dravlje Šiška	Central Ljublj. polje	Tomačevo Hrastje	Polje Zalog
class	1.1.1. 2	1.1.2. 4	1.1.3. 1	1.1.4. 1	1.2.1. 3	1.2.2. 3	1.2.3. 3	1.2.4. 4	1.2.5. 4	1.2.6. 4
The consumption of water by companies is greatest in the subunits of the central and eastern parts of Ljubljansko polje, where in addition to major users of water (production of beverages, processing of milk and meat, paper industry, etc.) there are also numerous smaller users of water. One of the largest users, the chemical industry, is located in the Jarški prod subunit.
Total annual quantity of water used in households and in companies per km2
In meaning, this indicator is the same as above. The total quantity of water used in the subunits is calculated according to the data on actual water use in companies considered in calculating the water tax and on the use of water by households calculated from the number of the residents and the average water consumption per resident.
Classes:
1.	low specific total consumption of water (up to 20,000 m3/km2);
2.	moderate specific total consumption of water (from 20,000 to 50,000 m3/km2);
3.	large specific total consumption of water (from 50,000 to 100,000 m3/km2);
4.	very large specific total consumption of water (above 100,000 m3/km2).
subunit	Tacen Gameljne	Jarški prod	Črnuče Nadgorica	Beričevo Brinje	Medno Vižmarje	Kleče Roje	Dravlje Šiška	Central Ljublj. polje	Tomačevo Hrastje	Polje Zalog
class	1.1.1. 2	1.1.2. 2	1.1.3. 4	1.1.4. 1	1.2.1. 3	1.2.2. 3	1.2.3. 4	1.2.4. 4	1.2.5. 4	1.2.6. 3
The specific consumption of water is very large in the greater part of Ljubljansko polje, and by far the largest in the consolidated built-up central part where households and industry use a lot of water and in the eastern effluent part with large water consumption by industry.
Efficiency of communal water purification plants
In our case, this indicator has less weight than the evaluation of environmental pollution relative to surface waters. Waste water from the settlements in Ljubljansko polje collected in the sewage system flows untreated into the Ljubljanica River, which does not contribute to the water source (the effluent part of the area with the groundwater) or to the environmental pollution of the water source.
Classes:
1.	more than 2/3 of the waste water is purified;
2.	1/3 to 2/3 of the waste water is purified;
3.	up to 1/3 of waste water is purified;
4.	waste water is not purified.
subunit	Tacen	Jarški	Črnuče	Beričevo	Medno	Kleče	Dravlje	Central	Tomačevo	Polje
	Gameljne	prod	Nadgorica	Brinje	Vižmarje	Roje	Šiška	Ljublj. polje	Hrastje	Zalog
	1.1.1.	1.1.2.	1.1.3.	1.1.4.	1.2.1.	1.2.2.	1.2.3.	1.2.4.	1.2.5.	1.2.6.
class	2	4	2	4	3	3	4	4	4	4
In Ljubljansko polje, there are three smaller communal purification plants with a total capability of 14,200 PE that purify less than 3% of all the waste water from the settlements. They purify partially gathered waste waters from settlements in the northeastern and northern (influent) parts of Ljubljansko polje. The water from the purification plants flows into the Sava River. A central purification plant located in the south-easternmost part of Ljubljansko polje should be completed by 2003. The majority of the waste water from industry and households flows from the influent part to the effluent part of Ljubljansko polje.
Pumping the groundwater
The exploitation of groundwater for the supply of potable water reduces its flow, influences the course of its flow, and lowers the water table in the area of pumping stations. Due to the depression sinks around the pumping stations, a consequence of the lowered water table, the (so-called »contagion«) areas of possible pollution of the catchment area of the water source increase.
Classes:
1.	no public or larger industrial pumping stations;
2.	public pumping stations with smaller extraction of groundwater or industrial pumping stations where the exploitation of the water source does not exceed 1/3 of its capacity;
3.	public and industrial pumping stations with larger extraction of groundwater exploiting up to 2/3 of capacity;
4.	pumping stations with very large water withdrawal of groundwater exceeding 2/3 of its capability.
subunit	Tacen Gameljne	Jar{ki prod	Črnuče Nadgorica	Beričevo Brinje	Medno Vižmarje	Kleče Roje	Dravlje Si{ka	Central Ljublj. polje	Tomačevo Hrastje	Polje Zalog
class	1.1.1. 1	1.1.2. 3	1.1.3. 1	1.1.4. 1	1.2.1. 2	1.2.2. 4	1.2.3. 1	1.2.4. 2	1.2.5. 4	1.2.6. 2
There are pumping stations for the central waterworks system of Ljubljana in three subunits of the central part of Ljubljansko polje where the dynamic supply of aquifer is used up to a large degree during low conditions of the groundwater. Along with pumping stations for the supply of the central system, water is also pumped by major industrial users. In other subunits, there are numerous wells for thermal pumps of individual users in addition to pumping stations for technological water.
4. Evaluation of landscape characteristics of the environment of the most important water source of Ljubljansko polje
4.1. Assessment of self-cleansing (regeneration and neutralization) capacities of the environment of the water source
Because they do not depend to the same degree on the landscape properties considered, the regeneration and neutralization capacities were first evaluated separately and then combined in a total evaluation.
The assessment of the regeneration capacities of the environment of the water source (ORSp) for a specific subunit is the sum of points divided into four classes that we got with the classes multiplied by ponders for the individual indicators. The weight given each individual indicator was determined by our own judgment. A higher final sum denotes a smaller regeneration capacity of the environment, and vice versa, a lower final sum denotes a higher regeneration capacity of the environment. We additionally considered the indicator for influents and course of groundwater, which was not specified with the classes.
TABLE 2: EVALUATION OF THE INDICATORS OF THE REGENERATION CAPACITIES OF THE ENVIRONMENT OF THE WATER SOURCE.
PREGLEDNICA 2: VREDNOTENJE KAZALCEV REGENERACIJSKIH SPOSOBNOSTI OKOLJA VODNEGA VIRA.
subunit	thickness of aquifer	covering layer	pedological and	Total number
	(groundwater quotient)	of aquifer	vegetation blanket	of points ORSp
weight	1.0	2.0	1.5	
Tacen Gameljne (1.1.1.)	4	3	2	11.0
Jarški prod (1.1.2.)	1	4	4	15.0
Črnuče Nadgorica (1.1.3.)	3	2	1	8.5
Beričevo Brinje (1.1.4.)	1	3	3	11.5
Medno Vižmarje (1.2.1.)	2	4	3	14.5
Kleče Roje (1.2.2.)	1	4	3	13.5
Dravlje Šiška (1.2.3.)	2	1	1, 3	7.0
Central Lj. polje (1.2.4.)	1	3	3	11.5
Tomačevo Hrastje (1.2.5.)	1	4	3, 4	14.0
Polje Zalog (1.2.6.)	2	3	3, 2	11.5
0RSP = TK1xRK1+TK2xRK2+TK3xRK3 °P': Težaweight of indicator 1 x Razredclass of indicator 1
Classes:
1.	regeneration capacities of the environment of the water source are large (below 8.0 points);
2.	regeneration capacities of the environment of the water source are moderate (8.0 to 11.5 points);
3.	regeneration capacities of the environment of the water source are low (12.0 to 15.0 points);
4.	regeneration capacities of the environment of the water source are critically low (above 15.0 points).
subunit	Tacen	Jarški	Črnuče	Beričevo	Medno	Kleče	Dravlje	Central	Tomačevo	Polje
	Gameljne	prod	Nadgorica	Brinje	Vižmarje	Roje	Šiška	Ljublj. polje	Hrastje	Zalog
	1.1.1.	1.1.2.	1.1.3.	1.1.4.	1.2.1.	1.2.2.	1.2.3.	1.2.4.	1.2.5.	1.2.6.
class	2	3	2	2	2*	2*	1	2	3	2
* according to number of points acquired, these subunits rank in the 3rd class, but taking into consideration the influents and course of groundwater indicator, we ranked them in the 2nd class.
TABLE 3: EVALUATION OF THE INDICATORS OF THE NEUTRALIZATION CAPACITIES OF THE ENVIRONMENT OF THE WATER SOURCE.
PREGLEDNICA 3: VREDNOTENJE KAZALCEV NEVTRALIZACIJSKIH SPOSOBNOSTI OKOLJA VODNEGA VIRA.
subunit	thickness of aquifer	depth of	covering layer	pedological and	Total number
	(groundwater quotient)	water table	of aquifer	vegetation blanket	of points ONSp
weight	1.5	1.5	1.5	1.0	
Tacen Gameljne (1.1.1.)	4	3	3	2	17.0
Jarški prod (1.1.2.)	1	3	4	4	16.0
Črnuče Nadgorica (1.1.3.)	3	3	2	1	13.0
Beričevo Brinje (1.1.4.)	1	3	3	3	13.5
Medno Vižmarje (1.2.1.)	2	2	4	3	15.0
Kleče Roje (1.2.2.)	1	1	4	3	12.0
Dravlje Šiška (1.2.3.)	2	1	1	1, 3	8.0
Central Lj. polje (1.2.4.)	1	1	3	3	10.5
Tomačevo Hrastje (1.2.5.)	1	2	4	3, 4	14.0
Polje Zalog (1.2.6.)	2	2	3	3, 2	13.0
ONSp = TD1 xRD1 + TD2xRD2 + TD3 xRD3 + TD4xRD4 Op.: Težaweight of indicator 1 x Razredclass of indicator 1
In the majority of the subunits, the regeneration capacities of the environment of the water source are assessed as moderate, largely due to the great thickness of the aquifer and the rapid regeneration of groundwater resulting from the intensive percolation of river water and precipitation, influents from neighbouring aquifers, and the relatively fast and large flow of the groundwater. Low regeneration capacities of the environment are only assessed in the subunits in the eastern part of Ljubljansko polje with very permeable covering layer and soil and poorer properties of the influents (lower quantity due to pumping, potentially larger danger of pollution due to the urbanization of the central part).
The assessment of the neutralization capacities of the environment of the water source (ONSp) for a specific subunit was acquired following the same procedure. The ponders were changed for several indicators according to our own judgment, and we took one more indicator into consideration.
Classes:
1.	neutralization capacities of the environment of the water source are large (below 11.0 points);
2.	neutralization capacities of the environment of the water source are moderate (11.0 to 15.5 points);
3.	neutralization capacities of the environment of the water source are low (16.0 to 21.0 points);
4.	neutralization capacities of the environment of the water source are critically low (above 21.0 points).
subunit	Tacen Gameljne	Jar{ki prod	Crnu~e Nadgorica	Beri~evo Brinje	Medno Vižmarje	Kle~e Roje	Dravlje Si{ka	Central Ljublj. polje	Toma~evo Hrastje	Polje Zalog
class	1.1.1. 3	1.1.2. 3	1.1.3. 2	1.1.4. 2	1.2.1. 2	1.2.2. 2	1.2.3. 1	1.2.4. 1	1.2.5. 2	1.2.6. 2
In most subunits in Ljubljansko polje, the neutralization capacities of the environment of the water source are assessed as moderate due to the great thickness of the aquifer, that is, the great quantity of groundwater and the predominant great depth of the water table. Permeable covering layer and soil are evaluated as unfavourable since they enable rapid percolation of precipitation and of potential pollution from the surface. Low neutralization capacities are assessed only in the subunits in the northern part of Ljubljansko polje where the groundwater is close to the surface.
The total evaluations of the regeneration and neutralization capacities of the environment of the water source were determined from the combined evaluations of the regeneration and neutralization capacities of the environment of the water source.
Classes:
1.	regeneration and neutralization capacities of the environment of the water source are large; sensitivity of the environment of the water source is small;
2.	regeneration and neutralization capacities of the environment of the water source are moderate; sensitivity of the environment of the water source is moderate;
3.	regeneration and neutralization capacities of the environment of the water source are low, sensitivity of the environment of the water source is large;
4.	regeneration and neutralization capacities of the environment of the water source are critically low; sensitivity of the environment of the water source is very large.
subunit	Tacen Gameljne	Jar{ki prod	Crnu~e Nadgorica	Beri~evo Brinje	Medno Vižmarje	Kle~e Roje	Dravlje Si{ka	Central Ljublj. polje	Toma~evo Hrastje	Polje Zalog
	1.1.1.	1.1.2.	1.1.3.	1.1.4.	1.2.1.	1.2.2.	1.2.3.	1.2.4.	1.2.5.	1.2.6.
component classes	2/3	3/3	2/2	2/2	2/2	2/2	1/1	2/1	3/2	2/2
total class	3	3	2	2	2	2	1	2	3	2
Large regeneration and neutralization capacities of the environment of the water source are assessed only in the subunit with a very deep water table and poorly permeable covering layer and soil in the influent part of Ljubljansko polje, while moderate capacities are assessed in several subunits that differ consider-
Slika 2: Regeneracijske in nevtralizacijske sposobnosti okolja vodnega vira (skupna ocena).
ably with respect to landscape properties. In the majority of the subunits, the thickness of the aquiferous sediments is large, as is the depth of the water table with the exception of two subunits in the northern part, and the covering layer of the aquifer is in most cases well permeable. Similar properties relative to permeability also apply for the soils covered only to a smaller degree by forest. Low regeneration and neutralization capacities of the environment were assessed for three subunits with a shallower level of the water table and well permeable covering layer over the aquifer. Two are found in the north and northwest of Ljubljansko polje, and the third is in the central part. In no cases were the regeneration and neutralization capacities of the environment evaluated as critically low, a reflection of the generally good characteristics of the environment of Ljubljana's most important water source.
4.2. Evaluation of the total environmental pollution of the water source
Total emission of waste waters, expressed in population (equivalent) units
The evaluation of total emission in the subunits is based on the quantity and pollution of waste waters of larger non-household users and on the number of the population in the subunits. The assessment of
the pollution (quantity and pollution of the waste water) from the sewage system was also of help. This indicator does not represent the actual environmental pollution of the water source because the waste waters are collected in the sewage system and diverted to the effluent part of Ljubljansko polje.
Classes:
1.	1000 PE and less;
2.	1001-10,000 PE;
3.	10,001-50,000 PE;
4.	50,001 PE and more.
subunit	Tacen Gameljne	Jar{ki prod	Črnuče Nadgorica	Beričevo Brinje	Medno Vižmarje	Kleče Roje	Dravlje Si{ka	Central Ljublj. polje	Tomačevo Hrastje	Polje Zalog
class	1.1.1. 2	1.1.2. 3	1.1.3. 2	1.1.4. 1	1.2.1. 2	1.2.2. 3	1.2.3. 3	1.2.4. 4	1.2.5. 3	1.2.6. 4
The largest number of population (equivalent) units were assessed for the subunits of the central and eastern effluent part of Ljubljansko polje where a great deal of polluted water comes from households and
1000 PEand less 1000 PE in manj
1001-10,000 PE 1001-10.000 PE
10.000-50,000	PE
10.001-50.000	PE
50,001 PE and more 50.001 PE in ve~
Figure 3: Environmental pollution with waste waters. Slika 3: Obremenjenost okolja z odpadnimi vodami.
industry, while the number is much lower in the subunits in the northern and western influent part where household waste waters prevail. According to specific environmental pollution (PE/km2), the subunits of the central and eastern part of Ljubljansko polje stand out with the largest estimates.
Pollution of surface waters
In 1995, the Sava River flowing across Ljubljansko polje ranked in the 2nd to 3rd quality class, and analyses of samples (Medno) showed increased content of polycyclic aromatic carbohydrates, nickel, and mineral oils. The sediment showed a rising content of heavy metals. According to saprobic indicators, the Sava River near Medno was ranked among moderately polluted rivers (Kakovost..., 1997). The quality of the river did not change as far as [entjakob in the central part of its course across Ljubljansko polje, which means that the pollution did not exceed self-cleansing capacities of the environment and the river. However, the quality of the Sava worsened considerably below Zalog in the effluent part of Ljubljansko polje where the Ljubljanica River carrying the waste waters ofLjubljana flows into it. In 1995, the Ljubljanica was ranked in the 4th quality class, and analyses indicated low saturation with oxygen, a high content of ammonium, phosphates, iron, nitrite, detergents, and high values of KPK with K2Cr2O7. Large amounts of metals were found in the sediment, particularly mercury and cadmium. According to the results of saprobic analyses, it was ranked among the critically burdened to heavily polluted rivers, and according to the results of bacteriological analyses, among the excessively polluted (Kakovost..., 1997). Below the confluence of the Ljubljanica with the Sava, the latter was ranked in the 3rd quality class. The basic indicators of pollution BPK5 and KPK with K2Cr2O7, nitrates, phosphates, and ammonium compounds increased strongly, and various heavy metals were present. According to the results of saprobic analyses, it ranked among the critically polluted rivers, and the bacteriological picture was very bad because the samples contained a larger number of bacteria of fecal origin (Kakovost..., 1997).
The quality of the groundwater depends significantly on the quality of the Sava in its upper and central course across Ljubljansko polje where the river water percolates intensively into the groundwater and represents a good half of the water needed for the regeneration of the dynamic stock of the aquifer. In the eastern part of Ljubljansko polje, the groundwater mostly drains into the Sava, and the possibility of influence from the polluted river is therefore smaller. The situation with the Ljubljanica, which runs along the southern edge of Ljubljansko polje and has poorly permeable riverbed, is similar. The groundwater is directed along its flow and the infiltration of the river water has not been determined.
Pollution of the groundwater
The quality of the groundwater of Ljubljansko polje is monitored by the Hydrological Institute of Slovenia on behalf of the state and also by the company that manages the waterworks and the sewage system. The analyses of samples taken at the pumping stations indicate that the pollution of pumped groundwater has not exceeded the defined maximum permissible values since 1992 nor has it for the most part exceeded the recommended values defined by WHO guidelines. In 1995, the consequences of industrial environmental pollution were most visible in the samples. In a majority of the samples, the presence of adsorbed organic compounds (AOX) was determined, the highest levels at the Hrastje and Jar{ki prod pumping stations and in two industrial wells. The content of heavy metals in the groundwater nowhere exceeded permissible values. Among the heavy metals, the content of copper and lead determined at the Hrastje pumping station and the chrome 6+ at Klece and Hrastje were the highest. Alow content of volatile organic solvents was traced in the majority of samples, and the permissible value of tetrachlorethylene was exceeded at the Hrastje pumping station. Mineral oils and pollution by communal waste waters was not traced in the analyses. Pesticide residues exceeded the limit value for individual pesticides (0.1 mg/l) in samples from the [entvid and Hrastje pumping stations and from two industrial wells. The content of nitrates in past years has not exceeded limit values applied according to our regulations (10 mg N/l or 44.27 mg NO3/l), although the EU recommended value (25 mg NO3/l) was exceeded frequently (Kakovost..., 1997).
The level of total environmental pollution of the water source was estimated with the assessment of indirect and direct sociogeographical indicators included in the quantitative and qualitative analyses of the
TABLE 4: FUNCTIONAL EVALUATION OF SOCIOGEOGRAPHICAL INDICATORS OF THE ENVIRONMENT. PREGLEDNICA 4: FUNKCIJSKO VREDNOTENJE DRUŽBENOGEOGRAFSKIH KAZALCEV OKOLJA.
subunit	population density	households connected to sewage system	proportion of cultivated field areas	proportion of forest	proportion of built-up areas	traffic	use of water by companies	total use of water/km2	water purification	pumping of groundwater	total total emissionspoints in PE OSlOp
weight	x 1.0	x 2.5	x 2.0	x 2.0	x 1.0	x 1.0	x 1.0	x 1.0	x 1.0	x 2.0	x 1.0
Tacen Gameljne (1.1.1.)	4	4	2	4	2	3	2	2	2	1	2 37.0
Jarški prod (1.1.2.)	4	2	2	4	1	4	4	2	4	3	*2 44.0
Črnuče Nadgorica (1.1.3.)	5	1	1	4	3	2	1	4	2	1	2 33.5
Beričevo Brinje (1.1.4.)	3	4	3	5	1	1	1	1	4	1	1 40.0
Medno Vižmarj (1.2.1.)	4	4	2	5	3	3	3	3	3	2	2 49.0
Kleče Roje (1.2.2.)	3	1	3	4	2	4	3	3	3	4	*2 44.5
Dravlje Šiška (1.2.3.)	5	1	1	5	4	4	3	4	4	1	3 43.5
Central Ljublj. polje (1.2.4.)	5	1	1	5	4	4	4	4	4	2	4 47.5
Tomačevo Hrastje (1.2.5.)	5	1	3	5	2	4	4	4	4	4	3 52.5
Polje Zalog (1.2.6.)	4	2	3	5	2	1	4	3	4	2	4 47.0
* two subunits were ranked according to PE/krrf of the surface area into the 2nd class although according to the sum of PE were in the 3rd class OSlOp = TD1 xRd1 +T[c xRD;+TD3x Rd,+ ... +TD11 xRd11
Op.. Težaweight 0| indicator x Razredclär, 0| indic:Jtor,
Slika 4: Stopnja skupne obremenjenosti okolja vodnega vira.
environment of the water source and with consideration of environmental pollution and emissions in the surface waters and the groundwater. The weights of individual indicators were determined by our own judgment and for each individual case.
In the assessment of the total environmental pollution of the water source, heavier weight was given to the indicators that best represent the actual environmental pollution of the water source. If the data for these indicators was sufficiently accurate, individual lower evaluated indicators such as population density and use of water could be omitted. Lesser weight was given to the indicators whose help could only anticipate the level of environmental pollution.
Classes:
1.	environmental pollution is small - up to 30.0 points;
2.	environmental pollution is moderate - 30.5 to 40.0 points;
3.	environmental pollution is large - 40.5 to 50 points;
4.	environmental pollution is very large - above 50 points.
Because of the intensive landscape use, there is no subunit in Ljubljansko polje where the total environmental pollution was assessed as small. Three smaller subunits at the northern edge of Ljubljansko polje with settlements of a suburban character and where there are no groundwater pumping stations were ranked
in the class of moderate pollution. The large total environmental pollution in the subunits of the western influent part of Ljubljansko polje and in the Jar{ki prod subunit and the very large pollution in the subunits of the central and eastern effluent part reflect the concentrations of population and economic activities in Ljubljansko polje. A great potential for environmental pollution is represented by the numerous gravel pits, »wild« dumping sites, and the storage, transportation, and use of materials hazardous for the groundwater that were not quantitatively defined in the evaluation. Considering the potential polluters and the quality of the groundwater, we placed the Central Ljubljansko polje and Polje Zalog subunits in the 4th class. All the pumping stations for the supply of waterworks are found in subunits with large or very large environmental pollution of the water source.
subunit	Tacen	Jar{ki	Črnuče	Beričevo	Medno	Kleče	Dravlje	Central	Tomačevo	Polje
	Gameljne	prod	Nadgorica	Brinje	Vižmarje	Roje	Si{ka	Ljublj. polje	Hrastje	Zalog
	1.1.1.	1.1.2.	1.1.3.	1.1.4.	1.2.1.	1.2.2.	1.2.3.	1.2.4.	1.2.5.	1.2.6.
class	2	3	2	2	3	3	3	4*	4	4*
* considering the qualitative indicators, these subunits were placed in a different class than they were ranked according to the sum of points
4.3. Assessment of the still acceptable environmental pollution of Ljubljana's most important water source
The assessment of the still acceptable pollution of the water source is the result of the evaluations of the self-cleansing (regeneration and neutralization) capacities and total environmental pollution.
Classes:
1.	capacity of the environment is not endangered;
2.	signs of diminished capacity of the environment are evident;
3.	pollution is already lessening the capacity of the environment;
4.	pollution exceeds the capacities of the environment.
subunit	Tacen Gameljne	Jar{ki prod	Črnuče Nadgorica	Beričevo Brinje	Medno Vižmarje	Kleče Roje	Dravlje Si{ka	Central Ljublj. polje	Tomačevo Hrastje	Polje Zalog
	1.1.1.	1.1.2.	1.1.3.	1.1.4.	1.2.1.	1.2.2.	1.2.3.	1.2.4.	1.2.5.	1.2.6.
class I	3	3	2	2	2	2	2	2	3	2
class II	2	3	2	2	3	3	3	4	4	4
class III	2	3	2	2	3	3	3	3	4	4*
* Pollution already exceeds the moderate self-cleansing capacities of the environment; additional pollution is therefore not acceptable, and the subunit was ranked in the 4th class.
Notes:
Class I - assessment of regeneration and neutralization capacities of the environment Class II - assessment of total and integral environmental pollution Class III - assessment of still acceptable pollution
In the subunits in the north of Ljubljansko polje, the total environmental pollution of the water source does not exceed its self-cleansing capacities. The pollution of surface waters indicates a threat in the sub-units of the central and western influent part where the total environmental pollution of the water source has already reduced the otherwise large self-cleansing ability of the environment, and therefore additional burdens that would further increase pollution are not acceptable. In the subunits of the eastern effluent part of Ljubljansko polje, the total environmental pollution of the water source already exceeds the capac-
Slika 5: Ocena še sprejemljivega obremenjevanja okolja vodnega vira.
ity of the environment, which also indicates the pollution of the groundwater, and further pollution would therefore only worsen the quality of the water source and for its permanent use must not be allowed.
4.4. Total evaluation of vulnerability and proposal for the level of protection for the environment of the water source
The total evaluation of the vulnerability of the environment of the water source is the result of the natural sensitivity of the environment or its regeneration and neutralization capacities and its reduced assimilation capacities due to excessive environmental pollution. The methodology of the vulnerability study (Studija..., 1996) foresees a descriptive assessment distributed into four classes:
1.	environment of the water source is slightly vulnerable;
2.	environment of the water source is moderately vulnerable;
3.	environment of the water source is very vulnerable;
4.	environment of the water source is critically vulnerable.
Landscape subunits where the vulnerability of the environment of the water source was evaluated as moderate are located in the northern, western, and southwestern parts of Ljubljansko polje. There are no ground-
Figure 6: Vulnerability of the environment of the water source. Slika 6: Ranljivost okolja vodnega vira.
water pumping stations for the central waterworks system within their boundaries, but because they are situated in the influent part, excessive pollution could mean the loss of the water source. With the exception of one subunit, the self-cleansing capacities of the environment were assessed as moderate, and the total pollution in three subunits in the north of Ljubljansko polje was assessed as moderate and in the remaining two as large. In the moderately vulnerable subunits of the central part of Ljubljansko polje, where environmental pollution is large or very large and has already reached its self-cleansing capacity, the environment of the water source is very vulnerable. There are pumping stations for waterworks in the Kleće Roje and Jar{ki prod subunits, and the Central Ljubljansko polje subunit is located on the influent side of the Hrastje pumping station that is already more exposed to environmental pollution due to its position east of Ljubljana. The Hrastje pumping station is in a subunit with a critically vulnerable assessment. The Polje Zalog subunit in the effluent part of Ljubljansko polje is in the same class. The total environmental pollution in both subunits is very large and already exceeds their capacities, which is evident in the pollution of the groundwater
The proposed level of protection for the environment of the water source is the result of preliminary assessments from the vulnerability study and in addition is determined by the locations of the groundwater pumping stations with their protection areas and the regime of protection. We must bear in mind that the area with groundwater divided into subunits is a whole and the consequences of excessive environmental pollution are reflected over the greater part of the area and not merely in the immediate vicinity of its source. Because of the interrelatedness of the subunits, the water conditions in Ljubljansko polje
are also a limiting factor in the subunits where there are no groundwater pumping stations for the supply of potable water.
Classes:
1.	water conditions are not the key limiting factor;
2.	water conditions are a limiting factor; protection measures against further major pollution are necessary;
3.	water conditions demand a high level of protection of the waters; an assessment of environmental impact is necessary for any additional burdening;
4.	water conditions are the key limiting factor; the strictest regime of protection is necessary and any additional burdening of the environment is precluded.
subunit Tacen	Jarški	Črnuče	Beričevo	Medno	Kleče	Dravlje	Central	Tomačevo	Polje
Gameljne prod	Nadgorica	Brinje	Vižmarje	Roje	Šiška	Ljublj. polje Hrastje	Zalog
1.1.1.	1.1.2.	1.1.3.	1.1.4.	1.2.1.	1.2.2.	1.2.3.	1.2.4.	1.2.5.	1.2.6.
class 2 4	2 2	3 4 3	3	4 4
water conditions are a limiting factor; protection measures against further major pollution are necessary vodne razmere so omejitveni dejavnik, potrebni so varovalni ukrepi pred dodatnimi velikimi obremenitvami
water conditions demand a high level of protection of the waters; an assessment of environmental impact is necessary for any additional burdening
vodne razmere zahtevajo visoko stopnjo varovanja voda, nujna je presoja vplivov na okolje pri vseh dodatnih obremenitvah
water conditions are the key limiting factor; the strictest regime of protection is necessary and any additional burdening of the environment is precluded
vodne razmere so ključen omejitveni dejavnik, potreben je najstrožji režim varovanja, izključene so vse dodatne obremenitve okolja
Figure 7: Proposal for the level of protection for the environment of the water source. Slika 7: Predlog stopnje varovanja okolja vodnega vira.
Water conditions are a limiting factor that require protection measures from further environmental pollution in the subunits of the northern part of Ljubljansko polje where there are no pumping stations for the supply of the waterworks and further pollution would only influence the quality of the groundwater to a smaller degree. Subunits where the water conditions demand a high level of protection of the water and where an assessment of environmental impact is necessary for any additional burdening of the environment are located in the western, southwestern, and central parts of Ljubljansko polje. Although there are no pumping stations in these subunits for the supply of the waterworks, further environmental pollution can strongly influence the quality of the groundwater in neighbouring subunits with pumping stations. The strictest regime of protection, where any additional burdening of the environment is precluded, is necessary in the subunits with pumping stations for the central waterworks system located in the central part of Ljubljansko polje and in the subunit with many industrial pumping stations in its eastern part.
5. Conclusion and discussion
With the methodology of the study of the vulnerability of the environment, we tried to evaluate the vulnerability of the environment of Ljubljana's most important water source, which is the consequence of human encroachment into the natural environment. The methodological approach based on the evaluation of a relatively large number of natural geographical and sociogeographical indicators confirmed our assumption that considerable differences relative to self-cleansing capacities and to environmental pollution exist between subunits within Ljubljansko polje. The expectation that the self-cleansing capacities of the environment of the water source are generally good was confirmed, since only as such can they mitigate the consequences of the intensive economic and urban use of land directly above the water source and maintain the quality of the potable groundwater. The sensitivity of the environment of Ljubljana's most important water source is decisively influenced by the coarse composition and great permeability of the sediments that enable the rapid regeneration of the dynamic supply of groundwater and simultaneously have a negative significance for the vulnerability of the environment as they enable the rapid spread of potential pollution from the surface into the underground. There are major differences between landscape subunits relative to the total environmental pollution, which is greatest in the central and eastern effluent parts of Ljubljansko polje and smaller in its influent part. The latter part is important for the protection of the pumping stations and the quality of the groundwater at the Klece and [entvid pumping stations that supply a good 60% of the water necessary to the waterworks system. According to our evaluation, the total environmental pollution in five subunits of central Ljubljansko polje has already reached the level of its capacity, and in the subunits of the eastern part has already exceeded it, making the environment of the water source critically vulnerable to further pollution. In other words, the environment of Ljubljana's most important water source would be much less vulnerable to further pollution if it were not already excessively polluted. All the pumping stations of water for the central waterworks system are located within strongly and critically vulnerable subunits, and the supply of potable water is totally dependent on »maintaining« the balance between the self-cleansing capacities and further environmental pollution. For the preservation of the quality of the water supply, the greatest problem is represented by unpredictable occurrences of environmental pollution such as fuel spills and spills of other hazardous materials from warehouses, in traffic accidents, fires, etc., as have already happened in the past. »Wild« dumping sites and those for hazardous wastes, gravel pits filled with rubbish, and deficient connection with and maintenance of the sewage system (which also drains off untreated industrial waste waters) also present a large danger. These potential sources of pollution were not considered in the assessment of the vulnerability of the environment of the water source as we were unable to define them quantitatively. After the study had been done, several questions occurred relating to the methodological approach, mostly regarding the large number of indicators considered. In future studies, only the most significant indicators will be selected, for which quality data - already another problem - would be required.
6. Bibliography
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Plut, D., 1994: Onesnaževanje vodnih virov - planetarne in slovenske razsežnosti. Petrolovi ekolo{ki dnevi, Ljubljana, str. 9-19.
Plut, D., 1996: Osnovni kazalci kakovosti mestnega okolja z vidika trajnostnega sonaravnega razvoja. Geografski vestnik, 68, str. 247-259.
Popis prebivalstva R Slovenije. 1991, Ljubljana, Statistićni urad R Slovenije.
Predlog poroćila o stanju okolja 1995. 1996, Poroćevalec, 6/1, 94 str.
Pravilnik o higienski neoporećnosti pitne vode. Uradni list SFRJ, 9/80, 33/87 in 13/90.
Pravilnik o zdravstveni ustreznosti pitne vode in pogojih za njeno zagotavljanje zaradi varovanja zdravja ljudi. Uradni list R Slovenije, 46/97.
Promet 95. Podatki o {tetju prometa na magistralnih in regionalnih cestah v R Sloveniji. 1996, Ljubljana, Republi{ka uprava za ceste.
Ridanovic, J., 1993: Hidrogeografija. Zagreb, Školska knjiga, 215 str.
Studija ranljivosti okolja. Vsebina in metodologija kot osnova za pripravo podzakonskega akta (delovno gradivo). 1996, Ljubljana, In{titut za geografijo, 73 str.
Tom{ić, B., M. Živanović, D. Ravnik, 1987: Hidrogeolo{ke raziskave za preskrbo z vodo na Ljubljanskem polju. Geofizikalne raziskave na Ljubljanskem polju. 1986, Ljubljana, Geolo{ki zavod Ljubljana.
Zakon o varstvu okolja (s komentarjem). 1994, Ljubljana.
7. Summary in Slovene - Povzetek
Landscape Vulnerability of Ljubljana's Most Important Water Source
Valentina Brečko Grubar
1.	Uvod
Prispevek Pokrajinska ranljivost najpomembnejšega vodnega vira Ljubljane je del obsežnejše raziskovalne naloge, kjer smo proučevali vpliv pokrajinskoekoloških dejavnikov na obnavljanje najpomembnejšega vodnega vira Ljubljane (Brečko, 1998). Za oskrbo glavnega mesta Slovenije s pitno vodo je letno porabljeno nad 25 mio m3 vode, zaradi velikih izgub v vodovodnem sistemu pa je potrebno zagotoviti skoraj 50 mio3. Vodni vir, ki zagotavlja 90 % pitne vode, je podtalnica Ljubljanskega polja. Nahaja se v peščeno-prodna-tih sedimentih Save, pod severnim delom mesta in njegovim obrobjem. Območje neposredne infiltracije padavin meri okoli 80km2 in dobi v povprečju 1400 mm padavin letno. Od skupne količine jih slaba polovica izhlapi, ostalo pa se večidel vključi v obnavljanje podtalnice, katere dinamična zaloga je ocenjena na 3 m3/s, skupna količina vode v vodonosniku pa presega 100 mio m3 (Breznik, Brilly, 1981). Dinamična zaloga vodonosnika Ljubljanskega polja predstavlja 15 % vseh raziskanih zalog podzemne vode v vodonosnikih z medzrnsko poroznostjo in 6 % vseh zalog podzemnih voda v Sloveniji. V širši okolici Ljubljane se nahajajo še druge podtalnice in izviri, vendar je zaradi bližine porabnikom vodni vir Ljubljanskega polja izjemnega pomena in zagotavlja pitno vodo že od pričetka gradnje vodovodnega sistema leta 1898. Podtalnica Ljubljanskega polja velja še danes za kakovostni vir, čeprav rezultati analiz kažejo na naraščajoči vpliv onesnaževanja okolja.
2.	Metodologija {tudije ranljivosti okolja
Studija ranljivosti okolja je analiza lastnosti pokrajinotvornih sestavin posameznih pokrajinskoekoloških enot glede nevtralizacijskih in regeneracijskih zmogljivosti ter proučitev polucijske obremenljivosti (Plut, 1995). Izdelavo študij ranljivosti okolja v Sloveniji določata 51. in 52. člen Zakona o varstvu okolja. »V planiranje in načrtovanje človekovih dejavnosti, s katerimi posega v okolje, zakon uvaja troje instrumentov, ki naj bi takšno poseganje v največji možni meri uskladili s temeljnimi načeli in zahtevami varstva okolja« (Zakon ..., 1994). Ti instrumenti so: ranljivost okolja in na njej utemeljena stopnja varovanja okolja in celovite presoje vplivov na okolje. Upoštevanje ranljivosti pri načrtovanih posegih v okolje je z 51. členom predpisano kot splošna obveznost. Osnutek metodologije študije ranljivosti okolja so vletu 1996 izdelali na Inštitutu za geografijo s sodelavci in predstavlja strokovno osnovo za pripravo podzakonskega akta. Metodologija se je dograjevala na osnovi izdelave vzorčnih študij ranljivosti okolja za nekatere občine, kjer so bili obravnavani naslednji pokrajinski elementi: relief z litologijo, zrak, vode, prst in gozd. Pri občinah Spodnjega Podravja s Prlekijo (Brečko, Hočevar idr., 1996) pa so bile prvič kot pokrajinski element obravnavane podtalnice in izbrani kazalci za količinsko in kakovostno analizo okolja glede podtalnice.
Ranljivost okolja je antropogeno povečana občutljivost okolja oz. spremenjena odzivnost okolja na na-daljne človekove posege v sestavo in dinamiko okolja. Vsaka dejavnost ali poseg spreminja naravno okolje, isti poseg pa ima lahko različen učinek na sestavine, zato je ranljivost okolja v njegovih različnih delih različna. Najbolj je ranljivo okolje z nizkimi samočistilnimi sposobnostmi, ki je močno obremenjeno in pokrajinsko degradirano. Z nadaljnim obremenjevanjem se ranljivost okolja za posege človeka še povečuje.
Nevtralizacijsko in regeneracijsko sposobnost okolja vodnega vira razumemo kot sposobnost okolja, da omili ali celo izniči negativne vplive onesnaževanja in drugih posegov človeka v okolje vodnega vira in teži k vzpostavitvi naravnega stanja, ki je bilo z določenim posegom v okolje porušeno. Samočistilne (absorpcijske) zmogljivosti so odvisne od lastnosti okolja v katerem se vodni vir nahaja kot tudi od lastnosti same pokrajinske sestavine - vode.
Postopek ocenjevanja ranljivosti okolja vodnega vira obsega:
•	kazalce količinske in kakovostne analize okolja;
•	oceno regeneracijskih in nevtralizacijskih sposobnosti okolja;
•	oceno dosežene stopnje skupne obremenjenosti okolja;
•	ceno še sprejemljivega obsega obremenjevanja okolja;
•	skupno oceno ranljivosti okolja in predlog stopnje varovanja okolja vodnega vira.
Količinska in kakovostna analiza obsega večje število fizičnogeografskih ter posrednih in neposrednih druž-benogeografskih kazalcev okolja, ki so osnova ocenjevanju samočistilnih sposobnosti in skupne obremenjenosti. Oceno regeneracijskih in nevtralizacijskih sposobnosti smo dobili z vrednotenjem, po lastni presoji izbranih in z razredi opredeljenih, fizičnogeografskih kazalcev, oceno skupne obremenjenosti okolja pa z vrednotenjem družbenogeografskih kazalcev. Ocena še sprejemljivega obsega obremenjevanja je rezultat razmerja med regeneracijskimi in nevtralizacijskimi sposobnostmi okolja in njegovo obremenjenostjo, navedene ocene skupaj pa so osnova za oceno ranljivosti ter predlog stopnje varovanja okolja.
Prostorska enota, za katero se ocenjujejo kazalci in določajo skupne ocene, je rezultat analize značilnosti pokrajinskih dejavnikov, ki odločilno vplivajo na občutljivost okolja vodnega vira. Kot prioritetne smo upoštevali globino do srednje gladine podtalnice, smer toka podtalnice ter prevladujočo zemljiško rabo. V pomoč so nam bile tudi meje vodovarstvenih območij črpališč podtalnice, ki so bile določene ob upoštevanju hidroloških, hidrogeoloških in tehničnih pogojev rabe vodnega vira. Ljubljansko polje smo razčlenili v deset podenot, ki se po velikosti precej razlikujejo, skupaj pa obsegajo 81,5 km2. Štiri podenote so na levi strani Save med Tacnom in Kamniško Bistrico, šest pa na desni med Mednim in sotočjem Ljubljanice s Savo. Poimenovali smo jih po naseljih in v enem primeru po legi podenote (slika 1).
3. Rezultati količinske in kakovostne analize okolja najpomembnejšega vodnega vira Ljubljane
3.1. Funkcijsko vrednotenje naravnogeografskih kazalcev okolja
Debelina vodonosnih sedimentov
Večja debelina vodonosnih sedimentov pomeni potencialno večjo dinamično zalogo podtalnice. Razredi so bili določeni glede na razmere v Sloveniji.
Razredi:
1.	zelo debel vodonosnik - debelina presega 20 m;
2.	debel vodonosnik - debelina je od 11 do 20 m;
3.	srednje debel vodonosnik - debelina je od 5 do 10 m;
4.	tanek vodonosnik - debelina vodonosnih sedimentov ne presega 5 m.
ime podenote	Tacen Gameljne	Jarški prod	Črnuče Nadgorica	Beričevo Brinje	Medno Vižmarje	Kleče Roje	Dravlje Šiška	Osred. Ljublj. polje	Tomačevo Hrastje	Polje Zalog
ocena	1.1.1. 4	1.1.2. 1	1.1.3. 3	1.1.4. 1	1.2.1. 2	1.2.2. 1	1.2.3. 2	1.2.4. 1	1.2.5. 1	1.2.6. 2
Samočistilna sposobnost okolja vodnega vira je večja pri večji dinamični zalogi, ta pa, odvisno tudi od poroznosti sedimentov, narašča z debelino vodonosnih sedimentov. Največjo debelino vodonosnika so
na Ljubljanskem polju izmerili v njegovem osrednjem delu južno od Save, v črpališču Kleče, kjer presega 70 m, nad 60 m je debel tudi v zahodnem (dotočnem) delu in na Jarškem produ na levem bregu Save. V vzhodnem (odtočnem) delu Ljubljanskega polja pa znaša debelina okoli 35 m (Breznik, Brilly, 1981).
Globina podtalnice
Večja globina podtalnice pomeni potencialno boljšo zaščito pred površinskim onesnaževanjem okolja, ker se onesnažena prenikajoča voda na poti do podtalnice lahko v večji meri očisti. Razredi so določeni glede na razmere v Sloveniji in z upoštevanjem tujih izkušenj (Europe's Environment, 1995)
Razredi:
1.	zelo globoka podtalnica - nad 20 m;
2.	globoka podtalnica - od 11 do 20 m;
3.	plitvo pod površjem - od 3 do 10 m;
4.	zelo plitvo pod površjem - pod 3 m, ob visokem stanju poplavna območja.
ime	Tacen	Jarški	Črnuče	Beričevo	Medno	Kleče	Dravlje	Osred.	Tomačevo	Polje
podenote	Gameljne	prod	Nadgorica	Brinje	Vižmarje	Roje	Šiška	Ljublj. polje	Hrastje	Zalog
	1.1.1.	1.1.2.	1.1.3.	1.1.4.	1.2.1.	1.2.2.	1.2.3.	1.2.4.	1.2.5.	1.2.6.
ocena	3	3	3	3	2	1	1	1	2	2
Podtalnica Ljubljanskega polja se uvršča med globlje podtalnice v Sloveniji. Njena globina na večjem delu presega 15 m, največja pa je v osrednjem delu južno od Save, kjer večinoma presega 20 m in ponekod celo 30 m. Vzdolž Save, severno od nje in v vzhodnem (odtočnem) delu Ljubljanskega polja so globine večinoma pod 10 m in največ 15 m (Hidrološki letopis, 1990-1996).
Dotoki in tok podtalnice
Na Ljubljanskem polju je obnavljanje dinamičnih zalog podtalnice ugodno zaradi izdatnih podzemnih in površinskih dotokov ter hitrega toka. Ti so posledica humidnosti podnebja, snežno-dežnega pretočnega režima Save kot glavnega vira obnavljanja zalog podtalnice, velikega gradienta podzemnega toka in velike poroznosti sedimentov. Količinsko bogati dotoki in velik pretok podtalnice pa so manj ugodni za kakovost podtalnice zaradi onesnaženosti okolja. V podenotah na dotočnem delu Ljubljanskega polja so ugodnejši pogoji za večje samočistilne sposobnosti, na odtočnem, vzhodnem delu, pa so pogoji mnogo slabši zaradi številnih potencialnih onesnaževalcev na osrednjem delu Ljubljanskega polja.
Prepustnost krovne plasti
Prepustnost ali permeabilnost je hidrogeološka lastnost kamnine, da prepušča vodo. Izraža se s koeficientom filtracije. Prepustnost je dobra pri koeficentu večjem od 10-5 m/s in slaba pri koeficientu od 10-5 do 10-9m/s. O neprepustnosti govorimo pri koeficientu pod 10-9m/s (Ridanovič, 1993). Odvisna je od velikosti por in je največja v prodnatih ter peščenih sedimentih velike zrnavosti, ki niso sprijeti. Slabša prepustnost krovne plasti ugodno vpliva na samočistilne sposobnosti okolja vodnega vira, ker upočasni dotok površinskih voda in povečuje možnosti samočiščenja onesnaženih dotokov.
Razredi:
1.	slabo prepustna krovna plast (pod 10-5 m/s);
2.	sklenjene slabo prepustne plasti so nad prepustnimi sedimenti ali med njimi;
3.	prepustna krovna plast z vmesnimi nesklenjenimi slabo prepustnimi plastmi;
4.	prepustna krovna plast (nad 10-5 m/s).
ime podenote	Tacen Gameljne	Jarški prod	Črnuče Nadgorica	Beričevo Brinje	Medno Vižmarje	Kleče Roje	Dravlje Šiška	Osred. Ljublj. polje	Tomačevo Hrastje	Polje Zalog
ocena	1.1.1. 3	1.1.2. 4	1.1.3. 2	1.1.4. 3	1.2.1. 4	1.2.2. 4	1.2.3. 1	1.2.4. 3	1.2.5. 4	1.2.6. 3
Glede prepustnosti krovne plasti so samočistilne sposobnosti okolja neugodne, saj vodonosnik večinoma prekrivajo prepustni nesprijeti in deloma sprijeti fluvioglacialni sedimenti (Osnovna geološka karta, 1974,1983). Pomembno vlogo imajo plasti glineno-ilovnatih sedimentov, ki se nahajajo med dobro prepustnimi plastmi v treh podenotah, v dveh podenotah pa jih v celoti prekrivajo. Glinene sedimente so odložili površinski vodni tokovi s porečji v obrobju Ljubljanskega polja, ki jih gradijo permo-karbonski skrilavi glinenci in peščenjaki.
Pedološka in vegetacijska odeja
Sloj prsti predstavlja razmeroma tanko plast krovnine in je za samočistilne sposobnosti okolja vodnega vira manj pomemben. Bolj odločilno vpliva na kmetijsko rabo zemljišč in na trajno poraslost z naravno vegetacijo, ki pa povečuje samočistilne sposobnosti okolja.
Razredi:
1.	neprepustna do slabo prepustna prst, večja poraslost;
2.	slabše prepustna plitva do globoka prst, manjša poraslost;
3.	prepustna srednje globoka do globoka prst, manjša poraslost;
4.	prepustna plitva prst, manjša poraslost.
ime podenote	Tacen Gameljne	Jarški prod	Črnuče Nadgorica	Beričevo Brinje	Medno Vižmarje	Kleče Roje	Dravlje Šiška	Osred. Ljublj. polje	Tomačevo Hrastje	Polje Zalog
ocena	1.1.1. 2	1.1.2. 4	1.1.3. 1	1.1.4. 3	1.2.1. 3	1.2.2. 3	1.2.3. 1,3	1.2.4. 3	1.2.5. 3,4	1.2.6. 3,2
Pri razvrščanju podenot v razrede glede lastnosti prsti in rastja se v nekaj primerih pojavljata dve oceni zaradi raznolikosti znotraj podenot. Te namreč večinoma segajo od Save do obrobnega hribovja z različno sestavo sedimentov in različnimi vodnimi razmerami, ki so odločilni za razvoj prsti. Na aluvialni ravnici vzdolž Save so nerazvite obrečne prsti na karbonatnem produ, na rečnih vršajih z glinenimi sedimenti so se razvile ilovnato-glinene prsti, ki so pogosto oglejene, na višjih terasah pa rjave prsti na karbonatnem produ (Pedološka karta, 1966 in 1985). Gozdnega rastja je največ na plitvih prsteh vzdolž Save in na slabše prepustnih, mokrotnih zemljiščih na obrobju Ljubljanskega polja.
3.2. Funkcijsko vrednotenje družbenogeografskih kazalcev okolja
Gostota prebivalstva (preb./km2)
Je najbolj splošni kazalec potencialnega obremenjevanja okolja. Večja gostota prebivalstva namreč pomeni večjo porabo pitne vode, večjo količino odpadnih vod in odpadkov, gostejši promet itd. Kazalec je pomemben zlasti takrat, ko gospodinjstva niso priključena na kanalizacijo oz. ne razpolagamo z drugimi indikatorji obremenjevanja okolja.
Razredi:
1.	nenaseljeno in redka (do 40 preb./km2);
2.	zmerna (41-100 preb./km2);
3.	gosta (101-500 preb./km2);
4.	zelo gosta (501-1000 preb./km2);
5.	zelo gosta urbana (1001 in več preb./km2).
										
ime podenote	Tacen Gameljne	Jarški prod	Črnuče Nadgorica	Beričevo Brinje	Medno Vižmarje	Kleče Roje	Dravlje Šiška	Osred. Ljublj. polje	Tomačevo Hrastje	Polje Zalog
ocena	1.1.1. 4	1.1.2. 4	1.1.3. 5	1.1.4. 3	1.2.1. 4	1.2.2. 3	1.2.3. 5	1.2.4. 5	1.2.5. 5	1.2.6. 4
Največja gostota prebivalstva je v podenotah, ki pokrivajo strnjeno pozidano mestno območje Ljubljane v osrednjem delu Ljubljanskega polja, ter na območjih nekdanje suburbanizacije, ki se postopoma zraš-čajo z mestom. Najmanjša gostota prebivalstva pa je v podenoti s polagrarnimi naselji na njegovem se-verovzhodem delu in v podenoti, ki večinoma pokriva varstveno območje dveh črpališč podtalnice severozahodno od mesta. Tu je bila rast naselij z odlokom o zaščiti podtalnice omejena že leta 1955.
Priključenost gospodinjstev na kanalizacijsko omrežje
Priključenost na kanalizacijsko omrežje se uvršča med najpomembnejše kazalce onesnaževanja okolja glede voda. Priključenost vseh porabnikov vode na vodotesno kanalizacijsko omrežje bi namreč bistveno zmanjšala nevarnost onesnaženja vodnega vira.
Razredi:
1.	75,1 % in več gospodinjstev je priključenih na kanalizacijsko omrežje;
2.	od 50,1 % do 75 % gospodinjstev je priključenih na kanalizacijsko omrežje;
3.	od 25,1 % do 50 % gospodinjstev je priključenih na kanalizacijsko omrežje;
4.	25 % in manj gospodinjstev je priključenih na kanalizacijsko omrežje.
ime podenote	Tacen Gameljne	Jarški prod	Črnuče Nadgorica	Beričevo Brinje	Medno Vižmarje	Kleče Roje	Dravlje Šiška	Osred. Ljublj. polje	Tomačevo Hrastje	Polje Zalog
ocena	1.1.1. 4	1.1.2. 2	1.1.3. 1	1.1.4. 4	1.2.1. 4	1.2.2. 1	1.2.3. 1	1.2.4. 1	1.2.5. 1	1.2.6. 2
V srednjem delu Ljubljanskega polja, ki ga v veliki meri pokriva strnjena mestna pozidava, je na kanalizacijsko omrežje priključenih nad 90 % gospodinjstev, na severnem in vzhodnem delu pa jih je priključenih le dobra polovica. Najslabše so razmere na zahodnem in severovzhodnem obrobju, kjer ima večina gospodinjstev pretočne greznice. Skupaj je na kanalizacijsko omrežje priključenih le dobri dve tretjini uporabnikov vode na Ljubljankem polju, zato je obremenjevanje okolja z odpadnimi vodami precejšnje.
Delež njivskih površin
S pomočjo deleža njivskih površin lahko le delno ocenimo obremenjevanje okolja vodnega vira zaradi kmetijske pridelave. Le to je namreč odvisno od izbora kultur, načina pridelave ter predvsem vnosov hranil in zaščitnih sredstev.
Razredi:
1.	pod 10%;
2.	od 10 do 25%;
3.	od 26 do 40%;
4.	nad 40 %.
ime podenote	Tacen Gameljne	Jarški prod	Črnuče Nadgorica	Beričevo Brinje	Medno Vižmarje	Kleče Roje	Dravlje Šiška	Osred. Ljublj. polje	Tomačevo Hrastje	Polje Zalog
ocena	1.1.1. 2	1.1.2. 2	1.1.3. 1	1.1.4. 3	1.2.1. 2	1.2.2. 3	1.2.3. 1	1.2.4. 1	1.2.5. 3	1.2.6. 3
Največji delež njivskih površin je bil leta 1993 v vzhodnem delu Ljubljanskega polja in na varstvenih območjih vodarn Kleče, Šentvid in Hrastje, najmanjši pa v njegovem osrednjem, pozidanem delu. Njivske površine so večinoma namenjene intenzivni pridelavi povrtnin za ljubljanski trg in krmnih kultur, zato predvidevamo, da je kmetijsko obremenjevanje na Ljubljanskem polju precejšnje.
Delež gozda
Večji delež gozda pomeni manjše obremenjevanje in večje samočistilne sposobnosti okolja vodnega vira, zato je eden pomembnejših kazalcev.
Razredi:
1.	od 71 do 100%;
2.	od 51 do 70%;
3.	od 31 do 50%;
4.	od 11 do 30%;
5.	pod 11%.
ime	Tacen	Jarški	Črnuče	Beričevo	Medno	Kleče	Dravlje	Osred.	Tomačevo	Polje
podenote	Gameljne	prod	Nadgorica	Brinje	Vižmarje	Roje	Šiška	Ljublj. polje	Hrastje	Zalog
	1.1.1.	1.1.2.	1.1.3.	1.1.4.	1.2.1.	1.2.2.	1.2.3.	1.2.4.	1.2.5.	1.2.6.
ocena	5	4	4	5	5	4	5	5	5	5
Na Ljubljanskem polju je skupni delež gozda zelo majhen in razen ob Savi ter na plitvih prsteh Jarškega in Tomačevskega proda severovzhodno od Ljubljane ni večjih sklenjenih gozdnih površin. V večini podenot je delež gozda manjši od 11 %, kar je za ranljivost okolja vodnega vira neugodno.
Delež pozidanih površin
Kazalec je pomemben zlasti kadar porabniki vode niso priključeni na kanalizacijo in meteorne vode s pozidanih površin niso zajete. Tu se namreč nahajajo različni potencialni onesnaževalci okolja vodnega vira, zaradi pozidanosti pa se zmanjša tudi prenikanje padavin v podtalje in poveča površinski odtok.
Razredi:
1.	pod 10%;
2.	od 10 do 30%;
3.	od 31 do 50%;
4.	nad 50 %.
ime	Tacen	Jarški	Črnuče	Beričevo	Medno	Kleče	Dravlje	Osred.	Tomačevo	Polje
podenote	Gameljne	prod	Nadgorica	Brinje	Vižmarje	Roje	Šiška	Ljublj. polje	Hrastje	Zalog
	1.1.1.	1.1.2.	1.1.3.	1.1.4.	1.2.1.	1.2.2.	1.2.3.	1.2.4.	1.2.5.	1.2.6.
ocena	2	1	3	1	3	2	4	4	2	2
Delež pozidanih površin je najmanjši na severnem in vzhodnem obrobju Ljubljanskega polja ter na vo-dovarstvenem območju črpališč Kleče in Šentvid. Največji, to je nad 80 %, pa je delež v osrednjem delu Ljubljanskega polja.
Prometna obremenitev
[tevilo vozil dnevno na posameznih cestnih odsekih omogoča le oceno potencialnega prometnega obremenjevanja okolja vodnega viraza. Za natančnejšo oceno bi namreč morali poznati sestavo prometa, njegovo dinamiko in opremljenost vozil.
Razredi:
1.	manjša - dnevna obremenitev večine cest ne presega 1000 vozil;
2.	zmerna - dnevna obremenitev večine cest je od 1000 do 3000 vozil;
3.	velika - dnevna obremenitev večine cest je od 3000 do 7000 vozil;
4.	zelo velika - dnevna obremenitev večine cest presega 7000 vozil.
ime	Tacen	Jar{ki	Črnuče	Beričevo	Medno	Kleče	Dravlje	Osred.	Tomačevo	Polje
podenote	Gameljne	prod	Nadgorica	Brinje	Vižmarje	Roje	Si{ka	Ljublj. polje	Hrastje	Zalog
	1.1.1.	1.1.2.	1.1.3.	1.1.4.	1.2.1.	1.2.2.	1.2.3.	1.2.4.	1.2.5.	1.2.6.
ocena	3	4	2	1	3	4	4	4	4	1
Promet povzroča na širšem območju Ljubljane oz. na večini Ljubljanskega polja z emisijami izpušnih plinov veliko onesnaževanje okolja, za izpiranje v podtalnico pa so problematične zlasti emisije svinca. Z rastjo gostote prometa v zadnjih letih narašča tudi število nesreč in nevarnost izlitja nevarnih snovi v podtalnico. S kazalcem dnevne obremenitve večine cest smo ugotovili, da je prometno obremenjevanje največje v podenotah, čez katere potekajo glavne mestne vpadnice in obvoznice (z nad 40.000 vozili/dan). Ker se meje nekaterih podenot pokrivajo s potekom glavnih prometnih povezav mesta z okolico, se prometna obremnitev cest odraža v ocenah dveh sosednjih podenot, torej je šteta dvakrat.
Neposredni kazalci obremenjevanja okolja vodnega vira Skupna količina porabljene vode v podjetjih
Je pomožni kazalec, ki je pomemben kadar gospodarski porabniki vode niso priključeni na kanalizacijsko omrežje oz. ne čistijo odpadnih vod pred izpustom v okolje. Ker se večina porabljene vode vrne v okolje kot odpadna voda, ki je pogosto specifično onesnažena, lahko s pomočjo porabe ocenimo »prispevek« podjetij k obremenjevanje okolja z odpadnimi vodami.
Razredi:
1.	ni porabnikov vode, manjše število porabnikov z zelo nizko porabo vode (skupaj do 10.000 m3 letno);
2.	manjše število porabnikov z nizko porabo vode (skupaj od 10.000 do 50.000 m3 letno);
3.	večje število porabnikov z zmerno skupno porabo vode ali eden večji porabnik vode (skupno od 50.000 do 500.000m3 letno);
4.	večje število porabnikov z visoko porabo vode (skupno nad 500.000 m3 letno).
ime podenote	Tacen Gameljne	Jar{ki prod	Črnuče Nadgorica	Beričevo Brinje	Medno Vižmarje	Kleče Roje	Dravlje Si{ka	Osred. Ljublj. polje	Tomačevo Hrastje	Polje Zalog
ocena	1.1.1. 2	1.1.2. 4	1.1.3. 1	1.1.4. 1	1.2.1. 3	1.2.2. 3	1.2.3. 3	1.2.4. 4	1.2.5. 4	1.2.6. 4
Poraba vode v podjetjih je največja v podenotah osrednjega in vzhodnega dela Ljubljanskega polja, kjer se poleg velikih (proizvodnja pijač, predelava mleka in mesa, papirna industrija itd.) nahajajo tudi številni manjši porabniki vode. V podenoti Jarški prod se nahaja eden največjih porabnikov, kemijska industrija.
Skupna letna koli~ina porabljene vode v gospodinjstvih in v podjetjih/km2
Kazalec je po pomenu enak predhodnemu. Skupna količina porabljene vode v podenotah je ocenjena po podatkih dejanske porabe v podjetjih, upoštevane pri obračunavanju takse za obremenjevanje voda, in porabe v gospodinjstvih, ocenjene iz števila prebivalstva in povprečne porabe vode na prebivalca.
Razredi:
1.	nizka specifična skupna poraba vode (do 20.000 m3/km2);
2.	zmerna specifična skupna poraba vode (od 20.000 do 50.000 m3/km2);
3.	velika specifična skupna poraba vode (od 50.000 do 100.000 m3/km2);
4.	zelo velika specifična skupna poraba vode (nad 100.000 m3/km2).
ime podenote	Tacen Gameljne	Jarški prod	Črnuče Nadgorica	Beričevo Brinje	Medno Vižmarje	Kleče Roje	Dravlje Šiška	Osred. Ljublj. polje	Tomačevo Hrastje	Polje Zalog
ocena	1.1.1. 2	1.1.2. 2	1.1.3. 4	1.1.4. 1	1.2.1. 3	1.2.2. 3	1.2.3. 4	1.2.4. 4	1.2.5. 4	1.2.6. 3
Specifična poraba vode je na večjem delu Ljubljanskega polja zelo velika, daleč največja pa je na strnjeno pozidanem osrednjem delu, kjer veliko vode porabijo gospodinjstva in gospodarstvo ter v vzhodnem, odtočnem delu z veliko porabo v gospodarstvu.
U~inkovitost komunalnih ~istilnih naprav
Kazalec ima v našem primeru manjšo težo kot, če bi ocenjevali obremenjevanje okolja glede površinskih voda. V kanalizacijski sistem zbrane odpadne vode naselij na Ljubljanskem polju namreč neprečiščene odtekajo v reko Ljubljanico, ki ne obnavlja vodnega vira (odtočni del območja s podtalnico) in ne predstavljajo obremenjevanja okolja vodnega vira.
Razredi:
1.	prečisti se več kot 2/3 odpadnih voda;
2.	prečisti se od 1/3 do 2/3 odpadnih voda;
3.	prečisti se do 1/3;
4.	odpadne vode se ne čistijo.
ime podenote	Tacen Gameljne	Jarški prod	Črnuče Nadgorica	Beričevo Brinje	Medno Vižmarje	Kleče Roje	Dravlje Šiška	Osred. Ljublj. polje	Tomačevo Hrastje	Polje Zalog
ocena	1.1.1. 2	1.1.2. 4	1.1.3. 2	1.1.4. 4	1.2.1. 3	1.2.2. 3	1.2.3. 4	1.2.4. 4	1.2.5. 4	1.2.6. 4
Na Ljubljanskem polju so tri manjše komunalne čistilne naprave s skupno zmogljivostjo 14.200 PE, ki čistijo pod 3 % vseh odpadnih vod iz naselij. Čistijo se deloma zajete odpadne vode naselij na severozahodnem in severnem (dotočnem) delu Ljubljanskega polja. Voda iz čistilnih naprav odteka v Savo. Centralna čistilna naprava, ki se nahaja na skrajnem jugovzhodnem delu Ljubljanskega polja, pa naj bi bila dokončana leta 2003. Večina odpadne vode iz industrije in gospodinjstev se pretaka iz dotočnega na odtočni del Ljubljanskega polja.
Crpanje podtalnice
Izkoriščanje podtalnice za oskrbo s pitno in tehnološko vodo zmanjšuje njen pretok, vpliva na smer toka in na območju vodarn znižuje gladino. Zaradi depresijskih lijakov črpališč (posledica znižanja gladine) se t. i. vplivna območja možnega onesnaženja zajetij vodnega vira povečujejo.
Razredi:
1.	ni javnih ali večjih industrijskih črpališč;
2.	javno črpali{če z manj{im odvzemom podtalnice ali industrijska črpali{ča, izkori{čenost vodnega vira ne presega 1/3 njegove zmogljivosti;
3.	javna in industrijska črpali{ča z večjim odvzemom podtalnice, izkori{čeno je do 2/3 zmogljivosti;
4.	črpali{ča z zelo velikim odvzemom podtalnice, ki presega 2/3 njegove zmogljivosti.
ime podenote	Tacen Gameljne	Jarški prod	Črnuče Nadgorica	Beričevo Brinje	Medno Vižmarje	Kleče Roje	Dravlje Šiška	Osred. Ljublj. polje	Tomačevo Hrastje	Polje Zalog
ocena	1.1.1. 1	1.1.2. 3	1.1.3. 1	1.1.4. 1	1.2.1. 2	1.2.2. 4	1.2.3. 1	1.2.4. 2	1.2.5. 4	1.2.6. 2
Črpališča za centralni vodovodni sistem Ljubljane so v treh podenotah srednjega dela Ljubljanskega polja, kjer je v dobr{ni meri izrabljena dinamična zaloga vodonosnika ob nizkem stanju podtalnice. Poleg črpali{č za oskrbo centralnega sistema jo črpajo tudi večji industrijski porabniki. V drugih podenotah so poleg črpali{č tehnolo{ke vode {tevilni vodnjaki za toplotne črpalke individualnih porabnikov.
4. Vrednotenje pokrajinskih značilnosti okolja najpomembnejšega vodnega vira Ljubljanskega polja
4.1. Ocena samocistilnih (regeneracijskih in in nevtralizacijskih) sposobnosti okolja vodnega vira
Regeneracijske in nevtralizacijske sposobnosti smo najprej ločeno ocenili, ker niso v enaki meri odvisne od upo{tevanih pokrajinskih lastnosti, potem pa jih združili v skupni oceni.
Ocena regeneracijskih sposobnosti okolja vodnega vira (ORSp) za določeno podenoto je v {tiri razrede razvr{čena vsota točk, ki smo jo dobili z razredi, pomnoženimi s ponderji za posamezne kazalce. Teža posameznega kazalca je bila določena po lastni presoji. Višja končna vsota pomeni vi{ji razred oz. manj{e regeneracijske sposobnosti okolja in obratno, nižja vsota višji razred oz. večje regeneracijske sposobnosti okolja. Dodatno smo upoštevali tudi kazalec dotoki in tok podtalnice, ki ni bil opredeljen z razredi.
Razredi:
1.	regeneracijske sposobnosti okolja vodnega vira so velike (pod 8,0 točk);
2.	regeneracijske sposobnosti okolja vodnega vira so zmerne (od 8,0 do 11,5 točk);
3.	regeneracijske sposobnosti okolja vodnega vira so nizke (od 12,0 do 15,0 točk);
4.	regeneracijske sposobnosti okolja vodnega vira so kritično nizke (nad 15,0 točk).
ime	Tacen	Jarški	Črnuče	Beričevo	Medno	Kleče	Dravlje	Osred.	Tomačevo	Polje
podenote	Gameljne	prod	Nadgorica	Brinje	Vižmarje	Roje	Šiška	Ljublj. polje	Hrastje	Zalog
	1.1.1.	1.1.2.	1.1.3.	1.1.4.	1.2.1.	1.2.2.	1.2.3.	1.2.4.	1.2.5.	1.2.6.
ocena	2	3	2	2	2*	2*	1	2	3	2
* po številu točksta se podenoti uvrstili v3. razred, z upoštevanjem kazalca dotoki in tok podtalnice pa smo ju uvrstili v2. razred.
V večini podenot so regeneracijske sposobnosti okolja vodnega vira ocenjene kot zmerne predvsem zaradi velike debeline vodonosnika in hitrega obnavljanja podtalnice, na kar vpliva intenzivno prenikanje rečne vode in padavin, dotoki iz sosednjih vodonosnikov ter razmeroma hiter in velik pretok podtalnice. Nizke regeneracijske sposobnosti okolja so ocenjene le v podenotah z zelo prepustno krovno plastjo in prstjo ter slabšimi lastnostmi dotokov (manjša količina zaradi črpanja, potencialno večja nevarnost onesnaženja zaradi urbanizacije osrednjega dela) na vzhodnem delu Ljubljanskega polja.
Ocena nevtralizacijskih sposobnosti okolja vodnega vira (ONSp) za določeno podenoto je bila dobljena po enakem postopku. Spremenili so se ponderji nekaterih kazalcev, določeni po lastni presoji, in upoštevan je bil en kazalec več.
Razredi:
1.	nevtralizacijske sposobnosti okolja vodnega vira so velike (pod 11,0 točk);
2.	nevtralizacijske sposobnosti okolja vodnega vira so zmerne (od 11,0 do 15,5 točk);
3.	nevtralizacijske sposobnosti okolja vodnega vira so nizke (od 16,0 do 21,0 točk);
4.	nevtralizacijske sposobnosti okolja vodnega vira so kritično nizke (nad 21,0 točk).
ime podenote	Tacen Gameljne	Jarški prod	Črnuče Nadgorica	Beričevo Brinje	Medno Vižmarje	Kleče Roje	Dravlje Šiška	Osred. Ljublj. polje	Tomačevo Hrastje	Polje Zalog
ocena	1.1.1. 3	1.1.2. 3	1.1.3. 2	1.1.4. 2	1.2.1. 2	1.2.2. 2	1.2.3. 1	1.2.4. 1	1.2.5. 2	1.2.6. 2
Nevtralizacijske sposobnosti okolja vodnega vira so v večini podenot na Ljubljanskem polju ocenjene kot zmerne zaradi velike debeline vodonosnika oz. velike količine podtalnice in prevladujoče velike globine podtalnice. Prepustna krovna plast in prst sta ocenjeni kot neugodni, ker omogočata hitro prenikanje poleg padavinam tudi potencialnemu onesnaženju s površja. Nizke nevtralizacijske sposobnosti so ocenjene le v podenotah na severnem delu Ljubljanskega polja, kjer je podtalnica plitvo pod površjem.
Skupne ocene regeneracijskih in nevtralizacijskih sposobnosti okolja vodnega vira smo določili iz sestavljenih ocen regeneracijskih in nevtralizacijskih sposobnosti okolja vodnega vira.
Razredi:
1.	regeneracijske in nevtralizacijske sposobnosti okolja vodnega vira so velike - občutljivost okolja vodnega vira je majhna;
2.	regeneracijske in nevtralizacijske sposobnosti okolja vodnega vira so zmerne - občutljivost okolja vodnega vira je zmerna;
3.	regeneracijske in nevtralizacijske sposobnosti okolja vodnega vira so nizke - občutljivost okolja vodnega vira je velika;
4.	regeneracijske in nevtralizacijske sposobnosti okolja vodnega vira so kritično nizke - občutljivost okolja vodnega vira je zelo velika.
ime	Tacen	Jarški	Črnuče	Beričevo	Medno	Kleče	Dravlje	Osred.	Tomačevo	Polje
podenote	Gameljne	prod	Nadgorica	Brinje	Vižmarje	Roje	Šiška	Ljublj. polje	Hrastje	Zalog
	1.1.1.	1.1.2.	1.1.3.	1.1.4.	1.2.1.	1.2.2.	1.2.3.	1.2.4.	1.2.5.	1.2.6.
sestav. ocena	2/3	3/3	2/2	2/2	2/2	2/2	1/1	2/1	3/2	2/2
skup. ocena	3	3	2	2	2	2	1	2	3	2
Velike regeneracijske in nevtralizacijske sposobnosti okolja vodnega vira so ocenjene le v podenoti z zelo globoko podtalnico ter s slabo prepustno krovno plastjo in prstjo na dotočnem delu Ljubljanskega polja, zmerne pa so ocenjene v več podenotah, ki se po upoštevanih pokrajinskih lastnostih precej razlikujejo. V večini podenot je debelina vodonosnih sedimentov velika, velika pa je tudi globina podtalnice, z izjemo dveh podenot na severnem delu, in krovna plast vodonosnika večinoma dobro prepustna. Podobne lastnosti glede prepustnosti veljajo tudi za prsti, ki jih le v manjši meri pokriva gozd. Nizke regeneracijske in nevtralizacijske sposobnosti okolja smo ocenili za tri podenote s plitvejšo gladino podtalnice in dobro prepustno krovno plastjo vodonosnika. Dve se nahajata na severu in severozahodu Ljubljanskega polja, tretja pa v srednjem delu. Regeneracijske in nevtralizacijske sposobnosti okolja niso bile nikjer ocenjene kot kritično nizke, kar je odraz splošno dobrih značilnosti okolja najpomembnejšega vodnega vira Ljubljane.
4.2. Ocena skupne obremenjenosti okolja vodnega vira
Skupne emisije odpadnih voda, podane v populacijskih (ekvivalentih) enotah
Ocena skupnih emisij v podenotah je zasnovana na količini ter onesnaženosti odpadnih vod večjih ne-gospodinjskih porabnikov in na številu prebivalstva v podenotah. V pomoč so nam bile tudi ocene obremenjenosti (količina in onesnaženost odpadne vode) kanalizacijskega omrežja. Kazalec ne predstavlja dejanskega obremenjevanja okolja vodnega vira, ker so odpadne vode zbrane v kanalizacijsko omrežje in speljane na odtočni del Ljubljanskega polja.
Razredi:
1.	1000 PE in manj;
2.	1001-10.000 PE;
3.	10.001-50.000 PE;
4.	50.001 PE in več.
ime podenote	Tacen Gameljne	Jar{ki prod	Črnuče Nadgorica	Beričevo Brinje	Medno Vižmarje	Kleče Roje	Dravlje Si{ka	Osred. Ljublj. polje	Tomačevo Hrastje	Polje Zalog
ocena	1.1.1. 2	1.1.2. 3	1.1.3. 2	1.1.4. 1	1.2.1. 2	1.2.2. 3	1.2.3. 3	1.2.4. 4	1.2.5. 3	1.2.6. 4
Največje število populacijskih (ekvivalentnih) enot je bilo ocenjeno za podenote srednjega in vzhodnega, odtočnega dela Ljubljanskega polja, kjer veliko onesnažene vode prihaja iz gospodinjstev in iz podjetij, precej manjše pa v podenotah na severnem in zahodnem, dotočnem delu, kjer prevladujejo gospodinjske odpadne vode. Po specifični obremenjenosti okolja (PE/km2) prav tako izstopajo z največjimi vrednostmi podenote srednjega in vzhodnega dela Ljubljanskoga polja.
Onesnaženost površinskih vodah
Sava je leta 1995 pritekala na Ljubljansko polje uvrščena v 2.-3. kakovostni razred, analize vzorcev (Medno) pa so pokazale povečano vsebnost policikličnih aromatskih ogljikovodikov, niklja in mineralnih olj. V sedimentu so ugotovili povišane vsebnosti težkih kovin. Po saprobioloških kazalcih je bila Sava pri Mednem uvrščena med zmerno obremenjene reke (Kakovost..., 1997). Do Šentjakoba v srednjem delu toka čez Ljubljansko polje se njena kakovost ni spremenila, kar pomeni, da obremenjevanje ni presegalo sa-močistilnih sposobnosti okolja in reke. Kakovost Save pa se je zelo poslabšala pod Zalogom na odtočnem Ljubljanskega polja, kjer se vanjo steka Ljubljanica z odpadnimi vodami Ljubljane. Ljubljanica je bila leta 1995 uvrščena v 4. kakovostni razred, analize pa so pokazale nizko nasičenost s kisikom, visoke vsebnosti amonija, fosfatov, železa, nitrita, detergentov in visoke vrednosti KPK s K2Cr2O7. V sedimentu so določili zelo veliko kovin, zlasti živega srebra in kadmija. Po rezultatih saprobioloških analiz je bila uvrščena med kritično obremenjene do močno onesnažene reke, po rezultatih bakterioloških analiz pa med prekomerno onesnažene (Kakovost., 1997). Po izlivu Ljubljanice vSavo, se je ta uvrstila v 3. kakovostni razred. Močno so bili povišani osnovni kazalci onesnaženja BPK5 in KPK s K2Cr2O7, nitrati, fosfati in amonijeve spojine ter prisotne različne težke kovine. Po rezultatih saprobioloških analiz se je uvrščala med kritično obremenjene reke, bakteriološka slika pa je bila zelo slaba, saj so vzorci vsebovali večje število bakterij fe-kalnega izvora (Kakovost..., 1997).
Za kakovost podtalnice je pomembna kakovost Save v njenem zgornjem in srednjem toku čez Ljubljansko polje, kje rečna voda intenzivno prenika v podtalnico in predstavlja dobro polovico vode, potrebne za obnavljanje dinamičnih zalog vodonosnika. V vzhodnem delu Ljubljanskega polja pa se podtalnica večinoma drenira v Savo, zato je možnost vpliva onesnažene reke manjša. Podobno je z Ljubljanico, ki teče po južnem robu Ljubljanskega polja in ima slabo prepustno rečno korito. Podtalnica je usmerjena vzdolž njenega toka in infiltracija rečne vode ni bila ugotovljena.
Onesnaženost podtalnice
Kakovost podtalnice Ljubljanskega polja spremljajo z republiškim monitoringom, ki ga izvaja Hidrometeorološki zavod R Slovenije, kakovosti pa spremljajo tudi v podjetju, ki upravlja z vodovodnim in kanalizacijskim sistemom. Analize v črpališčih zajetih vzorcev kažejo, da onesnaženost načrpane podtalnice po letu 1992 ne presega določenih maksimalnih dopustnih vrednosti oz. večinoma ne presega niti priporočljivih vrednosti po smernicah WHO. V letu 1995 so bile v vzorcih najbolj opazne posledice industrijskega onesnaževanja okolja. V večini vzorcev so ugotovili prisotnost adsorbiranih organskih spojin (AOX), najvišje v vodarnah Hrastje in Jarški prod ter v dveh industrijskih vodnjakih. Vsebnosti težkih kovin v podtalnici niso nikjer presegle dopustnih vrednosti, med njimi pa so bile najvišje vsebnosti bakra in svinca ugotovljene v vodarni Hrastje ter šestvalentnega kroma v Klečah in v Hrastju. Nizke vsebnosti lahkohlapnih organskih topil so zasledili v večini vzorcev, dopustno vrednost pa je tetrakloretilen presegel v vodarni Hrastje. Mineralnih olj in onesnaženja s komunalnimi odpadnimi vodami pri analiziranju niso zasledili. Ostanki pesticidov so presegli mejno vrednost za posamezni pesticid (0,1 mg/l) v vzorcih iz vodarn Šentvid in Hrastje ter iz dveh industrijskih vodnjakov, vsebnost nitratov pa v preteklih letih ni presegala mejnih vrednosti, veljavnih po naših predpisih (10 mg N/l ali 44,27 mg NO3/l), priporočljiva vrednost v EU (25 mg NO3/l) pa je bila večkrat presežena (Kakovost..., 1997).
Stopnjo skupne obremenjenosti okolja vodnega vira smo ocenili z vrednotenjem posrednih in neposrednih družbenogeografskih kazalcev, ki so vključeni v količinsko in kakovostno analizo okolja vodnega vira, z upoštevanjem emisijskega obremenjevanja okolja ter imisij v površinskih vodah in podtalnici. Teže posameznih kazalcev so bile določene po lastni presoji in za konkretni primer.
Pri ocenjevanju skupne obremenjenosti okolja vodnega vira smo dali večjo težo kazalcem, ki najbolje predstavljajo dejansko obremenjevanje okolja vodnega vira. V kolikor bi bili podatki za te kazalce dovolj natančni, bi nekatere nižje vrednotene kazalce, npr. gostoto prebivalstva, porabo vode, lahko izpustili. Manjšo težo smo dali kazalcem, s pomočjo katerih le predvidevamo raven obremenjenosti okolja.
Razredi:
1.	obremenjenost okolja je majhna - do 30,0 točk;
2.	obremenjenost okolja je zmerna - od 30,5 do 40 točk;
3.	obremenjenost okolja je velika - od 40,5 do 50 točk;
4.	obremenjenost okolja je zelo velika - nad 50 točk.
ime	Tacen	Jarški	Črnuče	Beričevo	Medno	Kleče	Dravlje	Osred.	Tomačevo	Polje
podenote	Gameljne	prod	Nadgorica	Brinje	Vižmarje	Roje	Šiška	Ljublj. polje	Hrastje	Zalog
	1.1.1.	1.1.2.	1.1.3.	1.1.4.	1.2.1.	1.2.2.	1.2.3.	1.2.4.	1.2.5.	1.2.6.
ocena	2	3	2	2	3	3	3	4*	4	4*
* podenote smo ob upoštevanju kvalitativnih kazalcev prerazporedili v drug razred kot so se uvrstile po seštevku točk.
Na Ljubljanskem polju zaradi intenzivne pokrajinske rabe ni podenote, kjer bi bila skupna obremenjenost okolja ocenjena kot majhna. V razred zmerne obremenjenosti so se uvrstile tri manjše podenote na severnem obrobju Ljubljanskega polja s suburbanim značajem naselij, kjer ni črpališč podtalnice. Velika skupna obremenjenost okolja v podenotah zahodnega, dotočnega dela Ljubljanskega polja in v podeno-ti Jarški prod ter zelo velika v podenotah srednjega in vzhodnega, odtočnega dela, je odraz koncentracije prebivalstva in gospodarskih dejavnosti na Ljubljanskem polju. Veliko potencialno obremenjevanje okolja predstavljajo številne gramoznice, »črna« odlagališča odpadkov ter skladiščenje, transport in uporaba podtalnici nevarnih snovi, ki jih pri ocenjevanju nismo kvantitativno opredelili. Ob upoštevanju t. i. potencialnih onesnaževalcev ter kakovosti podtalnice smo podenoti Osrednje Ljubljansko polje in Polje Zalog prerazporedili v 4. razred. Vsa črpališča za oskrbo vodovoda se nahajajo v podenotah z veliko in zelo veliko obremenjenostjo okolja vodnega vira.
4.3. Ocena {e sprejemljivega obremenjevanja okolja najpomembnej{ega vodnega vira Ljubljane
Ocena še sprejemljivega obremenjevanja okolja vodnega vira je rezultat ocen samočistilnih (regeneracijskih in nevtralizacijskih) sposobnosti in skupne obremenjenosti okolja.
Razredi:
1.	zmogljivost okolja ni ogrožena;
2.	kažejo se znaki zmanjšane zmogljivosti okolja;
3.	onesnaževanje že zmanjšuje zmogljivost okolja;
4.	onesnaževanje presega zmogljivost okolja.
ime podenote	Tacen Gameljne	Jarški prod	Črnuče Nadgorica	Beričevo Brinje	Medno Vižmarje	Kleče Roje	Dravlje Šiška	Osred. Ljublj. polje	Tomačevo Hrastje	Polje Zalog
	1.1.1.	1.1.2.	1.1.3.	1.1.4.	1.2.1.	1.2.2.	1.2.3.	1.2.4.	1.2.5.	1.2.6.
ocena I	3	3	2	2	2	2	2	2	3	2
ocena II	2	3	2	2	3	3	3	4	4	4
ocena III	2	3	2	2	3	3	3	3	4	4*
* Obremenjenost že presega zmerne samočistilne sposobnosti okolja, zato dodatno obremenjevanje ni sprejemljivo in smo podenoto uvrstili v4. razred.
Op.:
I	- ocena regeneracijskih in nevtralizacijskih sposobnosti okolja
II	- ocena skupne in integralne obremenjenosti okolja
III	- ocena še sprejemljivega obremenjevanja
V podenotah na severu Ljubljanskega polja skupna obremenjenost okolja vodnega vira ne presega njegovih samočistilnih sposobnosti, v podenotah srednjega in zahodnega, dotočnega dela skupna obremenjenost okolja vodnega vira že zmanjšuje sicer veliko samočistilno zmogljivost okolja, zato dodatne obremenitve, ki bi onesnaženost še povečale, niso sprejemljive. V podenotah vzhodnega, odtočnega dela Ljubljanskega polja pa skupno obremenjevanje okolja vodnega vira že presega zmogljivost okolja, kar kaže tudi onesnaženost podtalnice, zato bi dodatne obremenitve še poslabšale kakovost vodnega vira in za njegovo trajno rabo niso dopustne.
4.4. Skupna ocena ranljivosti in predlog stopnje varovanja okolja vodnega vira
Skupna ocena ranljivosti okolja vodnega vira je rezultat naravne občutljivosti okolja oz. njegovih regeneracijskih in nevtralizacijskih sposobnosti ter zaradi prekomernega obremenjevanja okolja zmanjšanih asimilacijskih zmogljivosti. Metodologija študije ranljivosti (Studija..., 1996) predvideva opisno oceno, razvrščeno v štiri razrede:
1.	okolje vodnega vira je malo ranljivo;
2.	okolje vodnega vira je zmerno ranljivo;
3.	okolje vodnega vira je močno ranljivo;
4.	okolje vodnega vira je kritično ranljivo.
Pokrajinske podenote, kjer je bila ranljivost okolja vodnega vira ocenjena kot zmerna se nahajajo na severnem, zahodnem in jugozahodnem obrobju Ljubljanskega polja. Znotraj njihovih meja ni črpališč podtalnice za centralni vodovodni sistem, ker pa se nahajajo na dotočnem delu bi prekomerno obremenjevanje lahko pomenilo izgubo vodnega vira. Samočistilne sposobnosti okolja so bile z izjemo ene podenote ocenjene kot zmerne, skupna obremenjenost pa je bila v treh podenotah na severu Ljubljanskega polja ocenjena kot zmerna, v preostalih dveh pa kot velika. V zmerno občutljivih podenotah srednjega dela Ljubljanskega polja, kjer je obremenjenost okolja velika oz. zelo velika in že dosega njegovo zmogljivost, pa je okolje vodnega vira močno ranljivo. V podenotah Kleče Roje in Jarški prod sta črpališči za vodo-
vod, podenota Osrednje Ljubljansko polje pa se nahaja na dotočni strani črpališča Hrastje, ki je že zaradi lege vzhodno od Ljubljane bolj izpostavljeno onesnaževanju okolja. Nahaja se v podenoti z ocenjeno kritično ranljivostjo okolja. V isti razred se je uvrstila tudi podenota Polje Zalog na odtočnem delu Ljubljanskega polja. Skupna obremenjenost okolja je v obeh zelo velika in že presega njegove zmogljivosti, kar kaže onesnaženje podtalnice.
Predlagana stopnja varovanja okolja vodnega vira je rezultat predhodnih ocen študije ranljivosti, poleg tega pa jo določajo lokacije črpališč podtalnice z varstvenimi območji in režimom varovanja. Upoštevati moramo, da je na podenote razčlenjeno območje s podtalnico celota in se posledice prekomernega obremenjevanja oz. onesnaževanja okolja odražajo na večjem delu območja in ne le v bližini njegovega vira. Zaradi medsebojne povezanosti podenot so na Ljubljanskem polju vodne razmere omejitveni dejavnik tudi v podenotah, kjer ni črpališč podtalnice za oskrbo s pitno vodo.
Razredi:
1.	vodne razmere niso ključen omejitveni dejavnik;
2.	vodne razmere so omejitveni dejavnik, potrebni so varovalni ukrepi pred dodatnimi velikimi obremenitvami;
3.	vodne razmere zahtevajo visoko stopnjo varovanja voda, nujna je presoja vplivov na okolje pri vseh dodatnih obremenitvah;
4.	vodne razmere so ključen omejitveni dejavnik, potreben je najstrožji režim varovanja, izključene so vse dodatne obremenitve okolja.
ime podenote	Tacen Gameljne	Jarški prod	Črnuče Nadgorica	Beričevo Brinje	Medno Vižmarje	Kleče Roje	Dravlje Šiška	Osred. Ljublj. polje	Tomačevo Hrastje	Polje Zalog
ocena	1.1.1. 2	1.1.2. 4	1.1.3. 2	1.1.4. 2	1.2.1. 3	1.2.2. 4	1.2.3. 3	1.2.4. 3	1.2.5. 4	1.2.6. 4
Vodne razmere so omejitveni dejavnik, ki zahteva varovalne ukrepe pred dodatnim obremenjevanjem okolja v podenotah severnega dela Ljubljanskega polja, kjer ni črpališč za oskrbo vodovoda, nadaljnje obremenjevanje okolja pa bi le v manjši meri vplivalo na kakovost podtalnice. Podenote, kjer vodne razmere zahtevajo visoko stopnjo varovanja voda in je pri vseh dodatnih obremenitvah nujna presoja vplivov na okolje, se nahajajo v zahodnem, jugozahodnem in osrednjem delu Ljubljanskega polja. Tudi v teh podenotah ni črpališč za oskrbo vodovoda, nadaljnje obremenjevanje okolja pa lahko močno vpliva na kakovost podtalnice v sosednjih podenotah s črpališči. Najstrožji režim varovanja, kjer so izključene vse dodatne obremenitve okolja, je potreben v podenotah s črpališči za centralni vodovodni sistem, ki se nahajajo v srednjem delu Ljubljanskega polja ter v podenoti z več industrijskimi črpališči na njegovem vzhodnem delu.
5. Sklep z diskusijo
Z metodologijo študije ranljivosti okolja smo poskušali oceniti ranljivost okolja najpomebnejšega vodnega vira Ljubljane, ki je posledica poseganj človeka v naravno okolje. Metodološki pristop, ki je zasnovan na vrednotenju razmeroma velikega števila naravnogeografskih in družbenogeografskih kazalcev je potrdil naša predvidevanja, da obstojijo znotraj Ljubljanskega polja, razčlenjenega na podenote, precejšnje razlike tako glede samočistilnih sposobnosti kot obremenjevanja okolja. Potrdila so se predvidevanja, da so samočistilne sposobnosti okolja vodnega vira splošno dobre, saj le take lahko zmanjšujejo posledice intenzivne gospodarske in urbane rabe zemljišč neposredno nad vodnim virom ter vzdržujejo kakovost pitne podtalnice. Na občutljivost okolja najpomembnejšega vodnega vira Ljubljane odločilno vpliva groba struktura in velika prepustnost sedimentov, ki omogoča hitro obnavljanje dinamičnih zalog podtalnice, istočasno pa ima negativni pomen za ranljivost okolja, ker omogoča hitro razširjenje potencialnega onesnaževanja s površja v podtalje. Večje razlike med pokrajinskimi podenotami so glede skupne obremenjenosti okolja, ki je največje v srednjem in vzhodnem, odtočnem delu Ljubljanskega polja ter manjše na njegovem dotočnem delu. Slednje je pomembno za zaščito črpališč in kakovosti podtalnice v črpališčih Kleče in Šentvid, ki zagotavljata dobrih 60 % potrebne vode vodovodnemu sistemu. Po naši
oceni je v petih podenotah srednjega dela Ljubljanskega polja skupna obremenjenost okolja že dosega stopnjo njegove zmogljivosti, v podenotah vzhodnega dela pa jo je že presegla in povzročila, da je okolje vodnega vira za nadaljnje obremenjevanje kritično ranljivo. Drugače povedano, okolje najpomembnejšega vodnega vira Ljubljane bi bilo mnogo manj ranljivo za nadaljnje obremenjevanje, če ne bi bilo že prekomerno okoljsko obremenjeno. Znotraj močno in kritično ranljivih podenot se tako nahajajo vsa črpališča vode za centralni vodovodni sistem in je oskrba s pitno vodo povsem odvisna od »vzdrževanja« razmerja med samočistilnimi sposobnostmi ter nadaljnjim obremenjevanjem okolja. Za ohranitev kakovosti vodne oskrbe predstavljajo največjo težavo nepredvidljiva onesnaženja okolja, kot so izlitja goriv in drugih nevarnih snovi iz skladišč, ob prometnih nesrečah, požarih ipd., ki so se v preteklosti že dogodila. Veliko nevarnost predstavljajo »črna« odlagališča, tudi nevarnih odpadkov, z odpadki zasipane gramoznice in pomanjkljiva priključenost in vzdrževanje kanalizacijskega omrežja, ki odvaja tudi neprečiščene industrijske odpadne vode. Naštete potencialne dejavnike onesnaženja pri ocenjevanju ranljivosti okolja vodnega vira nismo upoštevali, saj jih količinsko ni mogoče opredeliti. Po opravljeni študiji se nam postavljajo tudi nekatera vprašanja glede metodološkega pristopa, predvsem glede velikega števila upoštevanih kazalcev. V prihodnjih poskusih bi kazalo izbrati le najpomembnejše kazalce, za katere bi morali imeti kakovostne podatke, kar pa je že drug problem.