Sekundarni jezik: |
Angleški jezik |
Sekundarni naslov: |
Indices for simultaneously evaluation of hydrological drought |
Sekundarni povzetek: |
Drought is a phenomenon in which lack or insufficient rainfall over a long period of time results in a significant hydrological imbalance. This brings about a reduction of water stored in the soil, aquifers and lakes, and a decrease in the outflow to rivers. In the first part of this thesis we therefore described the phenomenon of drought, the reasons for its appearance and its characteristics, which distinguish it from other natural disasters. The rest of the thesis more importantly focuses on how to calculate, analyse and implement drought indices in order to determine hydrological drought. From the original time series for mean daily flow, low flow characteristic can be derived. The percentiles from the flow
duration curve (Q90) and mean annual minimum flow (MAM(1)) are two examples. 16 representative gauging stations across Slovenia are selected to test selected methods. Analysis of the results of calculated low flows are made and conclusions are drawn about the relationship between the low flow indices Q95, Q90, Q80 and MAM(7), MAM(30), MAM(60). When two indices most closely related are selected, the drought threshold level can be determined, below which the river flow is considered to be in deficit. The main goal is to determine the exact beginning and end of the hydrological drought, for which a method is used quantifiably defining whether the selected area is in deficit or not. With the sequent peak algorithm method (SPA) the beginning and the end, as well as the intensity and peak of hydrological drought can be determined. |
Sekundarne ključne besede: |
graduation thesis;hydrological drought;low flows;flow-duration curve;mean annual minima;sequent peak algorithm;threshold level;streamflow deficit; |
Vrsta datoteke: |
application/pdf |
Vrsta dela (COBISS): |
Diplomsko delo |
Komentar na gradivo: |
Univ. v Ljubljani, Fak. za gradbeništvo in geodezijo |
Strani: |
XIV, 79 str. |
Vrsta dela (ePrints): |
thesis |
Naslov (ePrints): |
Kazalci za sprotno vrednotenje hidrološke suše |
Ključne besede (ePrints): |
hidrološka suša;mali pretoki;krivulja trajanja;srednji letni minimum;algoritem zaporednih konic;sušni prag;deficit pretoka |
Ključne besede (ePrints, sekundarni jezik): |
Hydrological drought;low flows;flow-duration curve;mean annual minima;sequent peak algorithm;threshold level;streamflow deficit |
Povzetek (ePrints): |
Suša je pojav, ko se zaradi pomanjkanja ali nezadostne količine padavin v daljšem obdobju pojavi znatno hidrološko neravnovesje. To privede do zmanjšanja vodnih zalog v zemljini, vodonosnikih in jezerih ter zmanjšanja pretokov v vodotokih. V prvem delu diplomske naloge je zato opisan pojav suše, vzroki za njen nastanek in značilnosti, v katerih se razlikuje od drugih naravnih nesreč. V nadaljevanju pa je večji poudarek na določitvi, analizi in uporabi sušnih kazalcev za določevanje hidrološke suše. Osnova določitvi kazalcev malih pretokov so časovni nizi srednjih dnevnih podatkov. Iz teh lahko na različne načine izpeljemo kazalce malih pretokov kot so percentili iz krivulje trajanja pretokov npr. Q90, in najmanjši letni srednji dnevni pretok (MAM(1)). Izbrali smo 16 reprezentativnih vodomernih postaj po vsej Sloveniji in preverili izbrane metode. Narejena je analiza rezultatov
izračunanih malih pretokov in podane ugotovitve o medsebojni povezavi kazalcev malih pretokov najbolj pogosto uporabljenih kazalcev Q95, Q90, Q80 ter MAM(7), MAM(30) in MAM(60). Če izberemo kazalca, ki sta med sabo korelacijsko najbolj odvisna, lahko določimo sušni prag, pod katerim je
vodotok v deficitu. Naš glavni cilj pa je določiti točen začetek in konec hidrološke suše, za kar uporabimo metodo, ki nam količinsko definira, ali je izbrano območje v deficitu ali ne. Z metodo algoritma zaporednih konic (SPA) lahko poleg začetka in konca sušnega obdobja določimo tudi
intenziteto in vrh hidrološke suše. |
Povzetek (ePrints, sekundarni jezik): |
Drought is a phenomenon in which lack or insufficient rainfall over a long period of time results in a significant hydrological imbalance. This brings about a reduction of water stored in the soil, aquifers and lakes, and a decrease in the outflow to rivers. In the first part of this thesis we therefore described the phenomenon of drought, the reasons for its appearance and its characteristics, which distinguish it from other natural disasters. The rest of the thesis more importantly focuses on how to calculate, analyse and implement drought indices in order to determine hydrological drought. From the original time series for mean daily flow, low flow characteristic can be derived. The percentiles from the flow
duration curve (Q90) and mean annual minimum flow (MAM(1)) are two examples. 16 representative gauging stations across Slovenia are selected to test selected methods. Analysis of the results of calculated low flows are made and conclusions are drawn about the relationship between the low flow indices Q95, Q90, Q80 and MAM(7), MAM(30), MAM(60). When two indices most closely related are selected, the drought threshold level can be determined, below which the river flow is considered to be in deficit. The main goal is to determine the exact beginning and end of the hydrological drought, for which a method is used quantifiably defining whether the selected area is in deficit or not. With the sequent peak algorithm method (SPA) the beginning and the end, as well as the intensity and peak of hydrological drought can be determined. |
Ključne besede (ePrints, sekundarni jezik): |
Hydrological drought;low flows;flow-duration curve;mean annual minima;sequent peak algorithm;threshold level;streamflow deficit |
ID: |
8327176 |