Agnieszka Cupak

The use of NRCS synthetic unit hydrograph and Wackermann conceptual model in the simulation of a flood wave in an uncontrolled catchment

Abstract The paper presents the results of using two models: a conceptual model of Wackermann and a NRCS-UH synthetic unit hydrograph, for flow calculation in uncontrolled catchment of the Słonka, Poland. These models were chosen because of simplicity of models’ parameters evaluation, what is important from engineering calculation point of view. Flows with the probability of exceed amounting to 0.5%, 1%, 2%, 5%, 10%, 20%, and 50% and for different levels of the catchment moisture were evaluated. The flood waves generated in the Wackermann model were characterized by a short duration (over 2 hours), shorter concentration time (about 1 hour), and by about 70% higher peak flow values than those generated using the NRCS-UH method. A common feature of both methods were higher values of peak flows for the third level of the catchment moisture, as compared to the second level. It is also worth noticing that in both methods no flood wave was generated for the probabilities of 10, 20 and 50% and for the second level of the catchment moisture. It was assumed that hydrographs made with use Wackermann model better describe flood wave in mountain river, which Słonka is. W pracy przedstawiono wyniki analiz z wykorzystaniem dwóch modeli - konceptualnego modelu Wackermana oraz syntetycznego hydrogramu jednostkowego NRCS-UH - do określenia przepływów w zlewni rzeki Słonka, znajdującej się na obszarze Polski. Wybrane modele charakteryzują się łatwością określenia danych wejściowych do modelu, co jest istotne w aspekcie obliczeń inżynierskich. Obliczenia wykonano dla przepływów o prawdopodobieństwie wystąpienia przekroczenia wynoszącym: 0,5%, 1%, 2%, 5%, 10%, 20% i 50 dla różnych poziomów uwilgotnienia zlewni. Fale wezbraniowe, wygenerowane za pomocą modelu Wackermana, charakteryzowały się krótkim czasem trwania - ponad 2 godziny, krótszym czasem koncentracji - ok. 1 godziny i o ok. 70% większymi wartościami przepływów maksymalnych niż w przypadku fal wygenerowanych z wykorzystaniem metody SCS. Cechą wspólną obu metod były większe wartości przepływów maksymalnych dla III poziomu uwilgotnienia w stosunku do poziomu II. Można również zauważyć, że w przypadku obu metod oraz II poziomu uwilgotnienia zlewni nie wygenerowano fali wezbraniowej o prawdopodobieństwach przewyższenia 10, 20 i 50%.

The evaluation of heavy metal content in water and sediments of small reservoirs in light of various environmental quality regulations

This article reports the heavy metal concentrations assessed both in bottom sediments and water flowing into two small reservoirs at Krempna and Zesławice, southern Poland. The experiments were carried out in spring, summer, autumn and winter 2010–2011. The resulting concentrations of lead, cadmium, nickel, chromium and copper were compared with the Environmental Quality Standards, guidelines of the Regulation of the Minister of Environmental Protection, regulations of the Polish Geological Institute and State Institute of Environment Protection, Institute of Soil Science and Plant Cultivation, and with the regulations adopted in Germany, Denmark, the United States and Canada. Regarding the total heavy metal concentrations, water flowing into the examined reservoirs was not polluted. The highest concentrations of heavy metals were found in water flowing into the reservoirs in spring and summer. The heavy metal concentrations in sediments of the reservoirs at Krempna and Zesławice were much higher than the concentrations of the elements discussed present in waters flowing into these reservoirs.

Comparison of SCS-CN Determination Methodologies in a Heterogeneous Catchment

The aim of this study was to assess the runoff amount from a catchment characterized by diverse land uses by using the Soil Conservation Service Curve Number (SCS-CN) method based on Curve Number (CN) defined for dominant homogeneous elementary sub-regions. The calculations employed the SCS-CN method, involving the division of the catchment in two homogeneous parts and determining the runoff amount. The obtained results were compared with the results provided by three other CN determination methods, i.e. the Hawkins function, the kinetics equation, and a complementary error function peak. The catchment is located in a mountain dominated by forest land cover. Empirical CN-Precipitation (CNemp-P) data pairs were analyzed using the mentioned methods, and the highest quality score was achieved from model 1. The results suggest that dividing a catchment into two homogeneous areas and determining their separate CN parameters, used later on to calculate the runoff by means of the presented approach, could be an alternative to the standard methods. The described method is relatively easy, and as it does not require an adoption of numerous parameters, and it can be employed for designing hydraulic facilities.

Mean annuaL precipitation in a Mountain river catchMent area in the period 1984-2012 (the case of KaMienica river)

Summary The aim of the study is to evaluate the mean annual precipitation in the mountain river catchment area, in the period between 1984–2012. Data on daily rainfall totals was obtained from IMGW PIB in Warsaw, and it came from two weather stations: one in Nowy Sącz, and the other in Krynica. It has been demonstrated that during the multi-year period covered by the study, there were variations in terms of precipitation levels; the year 1987 should be considered extremely dry, while 2010, extremely wet – in the latter year, extreme rainfall was noted. In the analysed multi-year period, within the total annual precipitation, rain dominated during the first half year, which undoubtedly affects the hydrological regime of the Kamienica river.