Secondary language: |
English |
Secondary title: |
Low-flow analysis of the rivers in the Ljubljanica watershed |
Secondary abstract: |
Low flows usually occur during the dry season after longer periods of no rain. This results in a reduction of water stored in soils, aquifers and lakes, and a decrease in the outflow to the rivers.
The topic of the thesis is the analysis of low flows. The aim of the theoretical part of the thesis is to introduce the methods used in analyzing the low flows. In the practical part of the thesis the flow data from ARSO gauging stations at the Ljubljanica river basin is used to obtain the results of the low flow analysis using different methods. The methods used are: ninety-five percentile flow Q95, fifty percentile flow Q50, 7-day mean annual minima MAM(7), 1-day mean annual minima MAM(1) and the base-flow index BFI. Daily flow data of 15 gauging stations from 1924 to including 2011 are used. After analyzing the results of calculated low flows, conclusions are made about the relationships between the low flow indices Q95, Q50, MAM(7) MAM(1) and BFI. Correlations between indices are determined for each gauging station separately. The results show that the most closely related indices are Q95 and MAM(7). Strongly related are also Q95 and MAM(1). The weakest relation is between MAM(1) and
BFI. Comparison of the correlations between the gauging stations along the stream shows that
the best matches gauging stations are Moste (5080) and Vrhnika (5030). |
Secondary keywords: |
graduation thesis;civil engineering;low flows;drought;ninety-five percentile flow;base-flow index;flow-duration curve;mean annual minima; |
File type: |
application/pdf |
Type (COBISS): |
Undergraduate thesis |
Thesis comment: |
Univ. v Ljubljani, Fak. za gradbeništvo in geodezijo |
Pages: |
XII, 88 str., [14] pril. |
Type (ePrints): |
thesis |
Title (ePrints): |
Low - flow analysis of the rivers in the Ljubljanica watershed |
Keywords (ePrints): |
nizki pretoki;suša;petindevetdeset odstotni pretok;indeks
baznega odtoka;krivulja trajanja;srednji letni minimum |
Keywords (ePrints, secondary language): |
low flows;drought;ninety-five percentile flow;base-flow index;flow-duration curve;mean annual minima |
Abstract (ePrints): |
Nizki pretoki se ponavadi pojavljajo v sušnem obdobju, ko dalj časa ni obilnejših padavin. To privede do zmanjšanja vodnih zalog v zemljini, vodonosnikih in jezerih ter zmanjšanja pretokov v vodotokih.
Predmet diplomske naloge je analiza nizkih pretokov. V teoretičnem delu naloge so predstavljene metode, ki se uporabljajo pri analizah nizkih pretokov. V praktičnem delu naloge pa so s podatki merjenih pretokov na vodomernih postajah ARSO v porečju Ljubljanice, prikazani rezultati analize nizkih pretokov, dobljeni z različnimi metodami. Uporabljene metode so: petindevetdeset odstotni pretok Q95, petdeset odstotni pretok Q50, srednji letni sedemdnevni minimalni pretok MAM(7), srednji letni enodnevni minimalni
pretok MAM(1) in indeks baznega odtoka BFI. Uporabljeni so podatki dnevnih pretokov petnajstih vodomernih postaj od leta 1924 do vključno 2011. Po analizi rezultatov izračunanih nizkih pretokov so podane ugotovitve o medsebojni povezavi indeksov nizkih pretokov Q95, Q50, MAM(7), MAM(1) in BFI. Korelacije med indeksi so obravnavane za vsako vodomerno postajo posebej. Rezultati kažejo, da sta v najtesnejši zvezi indeksa Q95 in MAM(7). Močno povezana sta tudi Q95 in MAM(1). Najšibkeje povezana sta MAM(1) in BFI. Primerjava korelacij med vodomernimi postajami vzdolž toka kaže, da je med kazalniki nizkih pretokov najboljše ujemanje med vodomernima postajama Moste (5080) in Vrhnika (5030). |
Abstract (ePrints, secondary language): |
Low flows usually occur during the dry season after longer periods of no rain. This results in a reduction of water stored in soils, aquifers and lakes, and a decrease in the outflow to the rivers.
The topic of the thesis is the analysis of low flows. The aim of the theoretical part of the thesis is to introduce the methods used in analyzing the low flows. In the practical part of the thesis the flow data from ARSO gauging stations at the Ljubljanica river basin is used to obtain the results of the low flow analysis using different methods. The methods used are: ninety-five percentile flow Q95, fifty percentile flow Q50, 7-day mean annual minima MAM(7), 1-day mean annual minima MAM(1) and the base-flow index BFI. Daily flow data of 15 gauging stations from 1924 to including 2011 are used. After analyzing the results of calculated low flows, conclusions are made about the relationships between the low flow indices Q95, Q50, MAM(7) MAM(1) and BFI. Correlations between indices are determined for each gauging station separately. The results show that the most closely related indices are Q95 and MAM(7). Strongly related are also Q95 and MAM(1). The weakest relation is between MAM(1) and
BFI. Comparison of the correlations between the gauging stations along the stream shows that
the best matches gauging stations are Moste (5080) and Vrhnika (5030). |
Keywords (ePrints, secondary language): |
low flows;drought;ninety-five percentile flow;base-flow index;flow-duration curve;mean annual minima |
ID: |
8312842 |