Remembering Henry A. Christian 1931-1997

In memoriamIn memoria

Multi-criteria comparison between optional solutions for the rehabilitation of the bridge over Ozlenšček in Ozeljan

During their service life, faults and deficiencies that influece their functionality and appearance\ud emerge on bridges. In order to ensure safety, usability and aesthetic appearance, structures\ud have to undergo regular expert review and maintenance. Some bridges are damaged to the\ud extent where it is necessary to consider alternative solutions. This thesis compares solutions\ud to the bridge over Ozlenšček in Ozeljan.\ud In the first step, we compile an inventory of necessary remedial works on the basis of the\ud examination and tests on the bridge and calculate the estimated costs of comprehensive\ud rehabilitation. These costs are later compared with estimated costs of the newly constucted\ud bridge. The results show that the cost of the replacement construction is almost 15 times grater\ud than the cost of the rehabilitation, therefore we select the latter as a more rational and\ud economical solution. In addition to the comparison of cost, other criteria such as sustainability\ud and usability are used

Tracer tests as a tool for planning the monitoring of negative impacts of the Mozelj landfill (SE Slovenia) on karst waters

Tracer tests are one of the most useful researchmethods in karst hydrogeology and they have proved a valuable tool in various applied projects. In recent years we carried out a se­ries of tracer tests, and their results were used as the bases for planning the monitoring of water quality in the influence ar­eas of various pollution sources. In this paper, a case study of tracing at the landfill near Mozelj in southeastern Slovenia is described. The first goal was testing of the functioning of three monitoring boreholes, whichwere drilled at the margins of the landfill. As often happens in heterogeneous karst systems, they did not intersect the main flow paths from the landfill and are not suitable as monitoring points. On the other hand, the find­ings about the characteristics of tracer transport in the karst system and outflow throughthe karst springs were used for identifying the most suitable springs for monitoring and pre­paring an adequate sampling plan, whichshould be adapted to hydrological conditions

Time series analysis, modelling and assessment of optimal exploitation of the Nemanja karst springs, Serbia

The time series analysis was applied in the case-study of a karst aquifer in Serbia in order to study its functioning, hydrody­namic behavior and hydraulic properties. Focusing on the defi­nition of groundwater budget, due to very complex function­ing of karst systems the correlation and spectral analyses were used to emphasize the importance of transforming the input data – precipitation to effective infiltration. The characteriza­tion of karst aquifer was further improved by separating the output component – discharge to base-flow and fast-flow com­ponents. Additionally, the importance of these transformations was proved in application of the regression model for the sim­ulation of discharges based on the effective infiltration func­tions. A recharge-discharge model was applied in accordance withthe active groundwater management, defining optimal “exploitable” regimes, whichincluded the analyses of storage changes in karst water reservoirs under natural conditions, and calculation of the potential exploitation conditions

Hydrogeological research as a basis for the preparation of the plan of monitoring groundwater contamination: A Case Study of the Stara Vas Landfill near Postojna (SW Slovenia)

 V Sloveniji je na krasu trenutno aktivnih devet odlagališč komunalnih odpadkov, med drugimi tudi Stara vas pri Postojni. Ker je za kraška območja značilna močna razpokanost kamninske osnove in zelo dobra prepustnosti, izcedne vode z odlagališč še posebej ogrožajo podzemno vodo. Sposobnost naravne filtracije je v krasu majhna,obseg možnega negativnega vpliva pa zelo velik. Sedaj veljavna zakonodaja predpisuje obratovalni monitoring, del katerega je tudi merjenje parametrov onesnaženosti podzemnih vod z nevarnimi snovmi, če so v vplivnem območju odlagališča. Temelj za izdelavo načrta monitoringa so ustrezne hidrogeološke raziskave. Za primer Stare vasi smo poleg osnovnih geoloških in hidrogeoloških podatkov uporabili še rezultate sledilnih poskusov, ožje območje odlagališča pa smo podrobno tektonsko-litološko kartirali v merilu 1:5000. Na osnovi ugotovljenih značilnosti pretakanja vode v podzemlju in v skladu s predpisi smo določili 3 točke monitoringa znotraj (izvira Malenščica in Vipava, jama Fužina) in eno izven vplivnega območja odlagališča (Matijeva jama) ter določili način spremljanja kakovosti vode in izdatnosti   For the present 9 land fills on karst are still active in Slovenia, among them also the Stara vas land fill near Postojna. As strong fissuration of the rock base and very good permeability istypical for karst areas, the waste waters from the landfills particularly endanger the groundwater.The capacity of natural filtration in karst is very low and the dimension of possible negative impact is very high. The actual legislation regulates the performance of operational monitoring, a part of which is also the measurement of parameters of contamination of groundwater by hazardous substances, if they are in the area of influence of the landfill. Preparation of the monitoring plan is based on adequate hydrogeological researches. Besides basic geological and hydrogeological data also the results of tracer tests were used in the case study of the Stara vas landfill.Additionally, the detailed tectonic-lithological mapping in the scale 1:5000 was performed in the narrow area of the landfill.Based on defined characteristics of underground water flow and in accordance with the regulations 3 monitoring points inside (Malenščica and Vipava springs, Fužina cave) and one point outside the area of influence of the landfill (Matijeva jama cave) were selected. The monitoring plan for the observation of water quality and capacity was suggested

Vulnerability Mapping in the Recharge Area of the Korentan Spring, Slovenia

Zaradi dobro razvitega sistema kraških kanalov in razpok, ki omogoča hiter tok podzemne vode in tudi hiter prenos škodljivih snovi, so kraški vodonosniki zelo ranljivi za onesnaženje. Osnovo za njihovo ustrezno varovanje predstavljajo karte ranljivosti. Za izdelavo teh kart so bile razvite različne metode, pri oceni ranljivosti zaledja izvira Korentan pri Postojni pa smo uporabili metodo EPIK, ki je bila že večkrat uspešno preizkušena na krasu in stopnjo ranljivosti določa v odvisnosti od štirih parametrov: razvitosti epikrasa, učinkovitosti varovalnega pokrova, pogojev infiltracije in razvitosti kraške mreže. Za oceno posameznih parametrov smo uporabili različne raziskovalne metode kot so podrobno strukturno-litološko in geomorfološko kartiranje ter vzporedna analiza hidravličnih in fizikalno-kemičnih odzivov izvira na padavinske dogodke. Izdelana karta ranljivosti opredeljuje območja zelo velike, velike in zmerne ranljivosti znotraj zaledja izvira Korentana in jo lahko uporabimo kot osnovo za omejitev varstvenih pasov.Karst aquifers are very vulnerable to pollution due to well developed system of karst channels and fissures which enable fast groundwater flow and also fast transport of pollutants. An expert bases for their protection are vulnerability maps. Different methods for the construction of these maps were developed, and to assess the vulnerability of the recharge area of the Korentan spring near Postojna the EPIK method was used. In this method, which was many times successfully tested on karst, the degree of vulnerabilty is defined on the basis of four parameters: developement of the epikarst, effectiveness of the protective cover, infiltration conditions, and development of the karst network. For the assessment of individual parameters different research methods were used, such as detailed structural-lithological and geomorphological mapping, and combined analysis of hydraulic and physico-chemical responses of the spring to recharge events. Final result is the vulnerability map, which defines the areas of very high, high and moderate vulnerability within the recharge area of the Korentan spring and can be used to set up the protection zones