Natural and anthropogenic influences in the area of reservoirs Mola and Klivnik

Ekosistem je največja enota, ki opisuje procese, ki potekajo med neživo in živo naravo. Ta je sestavljen iz manjših ekosistemov, med katere spada tudi vodni ekosistem. V tej diplomski nalogi obravnavamo vodni ekosistem dveh jezer z vplivnim območjem. Za ugotavljanje kvalitete vode v jezerih Mola in Klivnik smo preučili proces evtrofikacije, ki ogroža ravnovesje v stoječih vodah. Na hitrost evtrofikacije vpliva več dejavnikov, ki jih delimo na naravne in antropogene. Stopnjo evtrofikacije najlažje določimo preko količine hranil v vodi, od katerih sta najpomembnejša fosfor ter dušik. Količine fosforja in dušika smo izračunali iz dveh virov. Prvi del količine pride v jezero preko kanalizacijskih odpadnih voda, drugi pa z vodami, ki se v jezero stekajo z vplivnega območja. Izračunane koncentracije fosforja in dušika v jezerih smo primerjali z meritvami, ki jih je opravila Agencija Republike Slovenije za okolje. Izračuni koncentracij so večinoma večji od dejanskih meritev. Do večjih odstopanj je prišlo pri koncentraciji fosforja, kjer so nekateri rezultati nekajkrat večji od izmerjene vrednosti. Pri dušiku je ta razlika manjša in lahko trdimo, da je izračun koncentracije dušika bolj natančen. Na podlagi stopnje evtrofikacije bi lahko v večini obravnavanega obdobja akumulaciji umestili med evtrofna jezera. Ker pa se določa stopnjo na podlagi izmerjenih vrednosti, ju umestimo med mezotrofna jezera. Na jezeru Klivnik antropogeni vplivi prispevajo 51 % količine fosforja, na jezeru Mola pa 56 %. Antropogeni vplivi imajo manjši vpliv na koncentracijo dušika in na Klivniku prispevajo 32 %, na jezeru Mola pa 37 % celotne koncentracije.Ecosystem describes the processes that take place between nonliving and living nature. The ecosystem is composed of smaller ecosystems, which include water ecosystems. In this diploma thesis water ecosystem represented by two lakes and theirs influence area will be discussed. We evaluated the quality of the water in the lakes Mola and Klivnik. The eutrophication process, which is the main threat to biodiversity in stagnant water, was examined. The speed of eutrophication is affected by several factors which can be classified as natural or anthropogenic. The degree of eutrophication can be determined by the quantity of nutrients in the water. The effect on eutrophication is dominated by two elements: phosphorus and nitrogen. The nutrients enter the lakes from two sources: by the sewage waste water and by runoff water from the influence area. The calculated concentration of phosphorus and nitrogen was compared with measurements performed by the Slovenian Environment Agency. Calculated concentrations are generally higher than measurements. Greater differences were observed for phosphorous concentrations. Therefore, the calculation of nitrogen concentrations is probably more accurate. Based on calculated values we could classify the lakes as eutrophic during most of the inspected period. However, based on measurements, which are more precise, the lakes are mesotrophic. For lake Klivnik the anthropogenic factors contribute 51 %, whereas for lake Mola they are responsible for 56 % of total phosphorous concentrations. Anthropogenic factors contribute to 32 % of total nitrogen on lake Klivnik and to 37 % of total nitrogen concentrations on lake Mola