Wyniki wyszukiwania - AGRO

1

Harmonic analysis of tides in Admiralty Bay

100%

Catewicz Z., Kowalik Z.

Oceanologia

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1983

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tom 15

2

Modélisation numérique spatiale d'écoulement de l'eau souterraine sur le périmètre alimenté par l'infiltration

100%

Krol P.

Annals of Warsaw Agricultural University. Land Reclamation

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2004

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tom 35a

3

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Investigations of hydraulic operating conditions of air lift pump with three types of air-water mixers

100%

Kalenik M.

Annals of Warsaw University of Life Sciences - SGGW. Land Reclamation

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2015

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tom 47

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nr 1

4

Variability of water flow in the Ezcurra Inlet

86%

Catewicz Z.

Oceanologia

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1983

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tom 15

5

Hydraulic conditions of water flow in seminatural fish pass, a case study of the Skorka barrage on the Glomia River

86%

Hammerling M., Kaluza T., Walczak N.

Acta Scientiarum Polonorum. Formatio Circumiectus

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2017

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tom 16

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nr 2

6

On the instabilities of estimated distributions of the POT (Peak Over Threshold) low flow characteristics

86%

Jakubowski W.

Meteorology Hydrology and Water Management. Research and Operational Applications

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2015

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tom 03

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nr 2

In a certain stream gauge profile, consider the low flow flows determined with the POT (Peak Over Threshold) method. Each of the flows can be described by three characteristics – deficit, duration and minimal flow. Values of the three-dimensional random variable depend on the choice of truncation level Qg (threshold flow) – POT method parameter. It is typically assumed that the threshold level is included within the range from Q95% to Q60% (Tallaksen, van Lanen 2004). However, in computational practice the Qg value is determined at the level of either Q90% to Q70%. This choice is made mainly from the hydrological (not statistical) point of view. In this paper the influence of the threshold flow on the form of estimated distributions of each of the above three characteristics is considered. The following distributions are chosen: − GEV (generalised extreme value distribution) – while examining the distribution of extremes; − log-normal – in the non-extreme case. In each of the examined stream gauge profiles the following algorithm was used: 1. from the curve of duration sums, two flow values Q90% and Q55% are chosen 2. for each flow from the range (Q90%, Q55%), using the Zelenhasić method (1987), a three-dimensional sequence is determined of observed deficits, durations and minimal flow values; 3. for each of the one-dimensional sequences, the parameters of the above distributions are estimated. The variability of the estimated quantiles and their intervals of confidence were shown with the example of three gauge profiles – Kuripapango (New Zealand), Bogusław (Prosna) and Bystrzyca Kłodzka (Nysa Kłodzka).

7

The evaluation of hydrodynamic balance at the Wkra River estuary

86%

Siwicki P., Urbanski J., Hejduk L., Gladecki J.

Meteorology Hydrology and Water Management. Research and Operational Applications

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2016

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tom 04

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nr 2

The river bed stability analysis at the Wkra estuary reach is presented in this paper. When a flood appears, channel and river bed erosion can reach a significant size. During such a situation, flow and water velocity exceed critical values for particular bed sediment grain sizes. This causes the breakage of bed armouring, and then bed mass motion begins. For the estimation of the sandy Wkra River bed the criteria of average velocity and bed armouring were applied with the use of ARMOUR software. The two Wkra River cross-sections at km 1+000 and km 3+200 distance were analysed. The calculation of the characteristics of bed sediment velocities was performed on the basis of, among other factors, probable river flow data, longitudinal slope, and grain size distribution of the bed. The results of the calculations were compared with average velocities in the analysed cross-sections. The results indicate the there is a threat to the stability of the Wkra River bed, especially during long-lasting high water stages. The prognosis of river bed stability loss performed by use of ARMOUR software shows that the bed armour breakage will take place in both considered cross-sections at relatively low water stages (about 40 cm), and mass motion of bed sediments in cross-section P-2 will occur at a flow of slightly lower than Q50% ,and in cross-section P-1 at flows greater then Q0,3%.

8

Untersuchung zum Niederschlag-Abfluss-Verhalten im Einzugsgebiet des Zagozdzonka Flusses

86%

Rottcher K., Homeier M., Banasik K.

Annals of Warsaw Agricultural University. Land Reclamation

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2000

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tom 30

15-27

9

Circulation of groundwater due to wave set-up on a permeable beach

86%

Massel S. R.

Oceanologia

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2001

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tom 43

|

nr 3

279-290

Sandy beaches are highly exploited but very dynamic and fragile environments. Driven by waves, the water flow through the beach body is able to transport oxygen, and hence help to maintain biological activity in the porous media. The paper presents a theoretical attempt to predict the groundwater circulation due to wave set-up. Two systems of circulations have been discovered, related to two different gradients of the set-up height. For the offshore gradient, the horizontal excess pressure gradient induces flow in the offshore direction. However, closer to the shore, the pressure gradient is reversed and the resulting flow moves shorewards.

10

Evaluation of some water extraction models in predicting water uptake of pigeonpea

86%

Ogunremi L. T.

International Agrophysics

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1996

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tom 10

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nr 2

11

A bypass flow model with a procedure to approximate precipitation intensity

86%

Walczak R. T., Slawinski C.

Acta Agrophysica

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2000

|

tom 35

Precipitation and intensity of precipitation are the most important parameters of soil profile water balance. Precipitation values give the information about amount of water reaching the soil surface. Intensity of the precipitation determines the amount of water accumulated in a soil profile and the amount of runoff water. The aim of the paper was to show the importance of consideration of precipitation distribution approximation in water dynamics modelling in soil profile taking into account preferential water flow.

12

Moisture conditions on a polder without an efficient drainage system. Case study

86%

Zaradny H.

International Agrophysics

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2004

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tom 18

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nr 3

13

Dispersion of Didymosphaenia geminata in the flowing waters of Southern Poland - new sites of species occurrence in the Orawska Watershed and the Orawska Basin

86%

Noga T.

Oceanological and Hydrobiological Studies

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2003

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tom 32

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nr 4

14

Ground water fed system restoration on the area of Przemkowsko-Przeclawskie Wetlands

72%

Brandyk A.

Annals of Warsaw University of Life Sciences - SGGW. Land Reclamation

|

2011

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tom 43

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nr 1

The aim of the paper is the estimation of hydrological conditions occurring on the area of Przemkowsko- Przecławskie Wetlands in the proposed water management scenarios, which are implemented to restore natural values of the wetland environment .In each of the scenarios, the operation parameters of hydraulic structures were changed, causing the potential increase of ground water alimentation to the wetland area. Common and recognized ground water flow model MODFLOW was used to calculate ground water levels for each scenario and to study the long –term effect of restoration measures on Przemkowsko – Przecławskie Wetlands. Following hydrological characteristics were analysed: mean of the mean ground water levels, inundation frequency, mean ground water amplitude and mean low ground water levels. These characteristics were modeled for the long-term period 1964-1985 for unsteady flow conditions and were compared with the values adopted from intact, reference wetlands. It was proved, that slowing down the outflow of ground water (scenario 1) didn’t provide hydrological conditions desired for the maintenance of swampy habitats. The combination of outflow slow down and restriction of ground water abstraction by existing pumping stations (scenario 2) didn’t guarantee the maintenance of desired values of hydrological characteristics for a swampy habitat as well. The realization of the proposed scenarios enables to keep proper conditions for wet and moist habitats. The management policy for Przemkowsko - Przeclawskie Wetlands should then be directed at the development of those habitats, providing broad realization of environmental protection goals.

15

Mechanical strength of stems in aquatic macrophytes

72%

Bociag K., Galka A., Lazarewicz T., Szmeja J.

Acta Societatis Botanicorum Poloniae

|

2009

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tom 78

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nr 3

181-187

In populations of submerged macrophytes, individuals are selected in terms of resistance to the effect of hydrodynamic forces. The aim of this study was to check whether individuals growing in river water are more tensile and bending resistant than plants occurring in places not exposed to flow stress. We determined the ultimate tensile strength of stems in four macrophyte species, Potamogeton natans, P. pectinatus, Batrachium fluitans and Chara fragilis, which occur in two environmental variants: in running (current velocity of 0.1-0.6 m/s-1) and stagnant water. In addition, flexure of P. natans stems from both environmental variants was examined. What is more, the type and arrangement of strengthening structures in stems of the plants under study were determined. Potamogeton natans stems are the most resistant to stretching (15.6±4.7 N), while stems of P. pectinatus (3.3±1.0 N) and Batrachium fluitans (2.6±0.8 N) are less resistant. Chara fragilis (0.6±0.3 N) has the least resistant stems. Batrachium, Chara and P. pectinatus are more resistant to stretching if they occur in a river current, whereas P. natans, in stagnant lake water. Ultimate bending moment of P. natans stems from lakes is also much greater than of stems from a river (9.75•10-3 – 4.25•10-3 Nm as compared to 2.12•10-3 – 1.00•10-3 Nm). The resistance of stems to breaking is directly proportional to the stem and thallus cross sectional areas. On the one hand, in all the studied Cormophyta species, the more resistant stems (in P. natans from stagnant water, in the others from running water) are thicker and characterised by a higher contribution of air spaces in the overall stem cross-section. On the other hand, the stems retain their species specific structure and have a similar proportion of strengthening elements.

16

Phosphorus runoff from small agricultural catchments under different land use intensity

72%

Skwierawski A., Sobczynska-Wojcik K., Rafalowska M.

Journal of Elementology

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2008

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tom 13

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nr 4

637-646

The study was carried out in the hydrologic year 2006 and comprised two small agricultural catchments in the Masurian Lakeland. Both catchments possessed very large water retention potential (presence of buffer zones and surface waters in the catchments) but they differed in the intensity of agricultural production. The study has demonstrated that the concentration of phosphorus in the surface waters flowing from the catchments ranged from 0.12 to 0.43 mg⋅dm-3. The catchments were characterised by low indices of water overland flow (0.32-1.67 dm3⋅s-1⋅km-2), which was a decisive factor shaping the runoff of phosphorus (from 0.013 to 0.060 kg⋅ha-1⋅year-1. A subcatchment dewatered by a pipe drain system, which was used for comparison, had a water flow of 3.54 dm3⋅s-1⋅km-2 and exported much more phosphorus with its surface waters (0.39 kg⋅ha-1⋅year-1). The results obtained during our study emphasise an important role played by small landscape water retention elements in both catchments and the efficiency of buffer zones at a contact of water bodies and fields in reducing the runoff of biogenic substances, especially when agricultural production carried out on a given catchment is intensive.

17

Influence of Slup dam reservoir on flow and quality of water in the Nysa Szalona River

72%

Wiatkowski M.

Polish Journal of Environmental Studies

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2011

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tom 20

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nr 2

After a flood in 1997 that affected the basin of the upper and central Odra River (on selected dam reservoirs, including drinking water reservoirs), the operational water fill ordinates were lowered in order to increase the flood capacity of the reservoirs. One of these reservoirs is the Słup. Its main functions include: compensation of water outflow from the Nysa Szalona and flood protection. This paper presents the analysis of flows of the Nysa Szalona River below and above the Słup Reservoir, analysis of the water table and reservoir capacity, plus quality assessment of water flowing in and out of the reservoir, including stored water. Water quality assessment was based on analyses of the following parameters: NO₃⁻, NO₂⁻, NH₄⁺, PO₄³⁻, BOD₅, CODMn, DO, Cl⁻, SO₄²⁻, TOC, electrolytic conductivity, water temperature, and TSS. The study shows that in the period of 2005-08 the reservoir significantly compensated flows in the Nysa Szalona River. Significant relationship between the volume of water flowing out of the reservoir and volume of water flowing into the reservoir was observed (statistical significance at the level of p<0.05). A statistical analysis of linear correlations among all investigated water quality indicators at particular measurement points was also carried out. Significance of differences among some average water quality indicators with regard to inflowing and outflowing water was found. In order to protect the Słup Reservoir from pollution, construction of a pre-dam in the reservoir backwater is proposed.

18

Wpływ zbiornika Wióry na przebieg niżówek rzeki Świśliny

72%

Kaznowska E., Madra E.

Acta Scientiarum Polonorum. Architectura

|

2016

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tom 15

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nr 4

Celem pracy jest ocena wpływu zbiornika Wióry na przebieg niżówek rzeki Świśliny. Praca zawiera charakterystykę zjawiska niżówki, będącej okresem utrzymywania się niskich przepływów w rzekach. Zagadnienie niżówek jest rozpatrywane w profilu Nietulisko Duże, zamykającym zlewnię rzeki Świśliny o powierzchni 402,83 km², w której w 2005 roku oddano do eksploatacji zbiornik retencyjny Wióry. Świślina wraz z dopływami odprowadza wody z Gór Świętokrzyskich, najwyższej części dorzecza rzeki Kamiennej. Duża zmienność przepływów, długie okresy występowania niskich przepływów, gwałtowne powodzie, to główne powody wybudowania zbiornika Wióry. Obecnie zbiornik Wióry jest największym i najbardziej nowoczesnym zbiornikiem wodnym w zlewni rzeki Kamiennej. Podstawą analiz były przepływy dobowe z okresu 1961–2013. Za niżówkę uznano sekwencję przepływów, trwającą minimum 10 dni, o wartościach równych i mniejszych od przepływu Q90% = 0,40 m³·s⁻¹ odczytanego z krzywej sum czasu trwania przepływów wraz z wyższymi. Najdłuższa niżówka z całego wielolecia 1961–2013 rozpoczęła się w kwietniu 2006 roku, a skończyła w lutym 2007 roku w okresie po wybudowaniu zbiornika Wióry.

19

Modelling flow in the porous bottom of the Barents Sea shelf

72%

Massel S. R.

Oceanologia

|

2013

|

tom 55

|

nr 1

20

Quality indices of waters flowing away from catchments of small retention reservoirs planned in the Krakow region

72%

Kanownik W., Rajda W.

Electronic Journal of Polish Agricultural Universities. Series Environmental Development

|

2010

|

tom 13

|

nr 3

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