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Evaluation of the effects of land-use change and increasing deforestation in the Sapanca Basin on total suspended solids (TSS) movement with predictive models

Temiz Temel, Sonmez Osman, Dogan Emrah, Oner Adnan, Opan Mücahit

Acta Geophysica

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2022

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Vol. 70, no 3

1331--1347

EN

Sapanca Lake is a tectonically sourced freshwater resource and one of the rare natural water resources used as a source of drinking water. This study examined the change of land use and lake area in the natural water source basin subjected to human pressure for years. Landsat 5 TM (1987) and Landsat 8 TM (2010) satellite images were used. Satellite images were analyzed using ArcGIS 10.1 software. As a result of the analysis, it was observed that the natural vegetation was significantly destroyed between 1987 and 2010. Besides, the bathymetry maps of Lake Sapanca belonging to the years 1990 and 2010 were also examined, and accordingly, it was determined that there was a 2% reduction in the lake surface area. The decrease in the volume of the lake was thought to be due to sedimentation movement caused by land-use change, and the total amount of suspended solids, grain size, discharge, and temperature measurements were made between 2012 and 2014 in 12 streams which are sources of Sapanca Lake. Sediment prediction models have been developed under two different scenarios using measurement data from side streams. Artificial neural networks (ANN), Sediment rating curve, and multiple linear regression models were examined within the scenario models, and comparisons were made between the models. It was determined that ANN achieved the closest results with the measurement data.

2

Acoustic based assessment of cross-sectional concentration inhomogeneity at a suspended sediment monitoring station in a large river

Pomázi Flóra, Baranya Sándor

Acta Geophysica

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2022

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Vol. 70, no 5

2361--2377

EN

Establishing and operating a harmonized sediment monitoring system along large rivers such as the Danube River is a challenging international task. As an element of such a system, a new monitoring site with state-of-the-art instrumentation is currently under development in the Upper-Hungarian section of the Danube River. The monitoring station will consist of a nearbank optical backscatter sensor and a horizontal acoustic Doppler current profiler (H-ADCP). As previous studies showed, the suspended sediment concentration (SSC) that is continuously measured with near-bank sensors can significantly enhance the temporal resolution of sediment transport monitoring. However, sediment plumes from tributary inflows upstream of the monitoring station can alter the detected near-bank concentrations, eventually biasing the sediment load estimation. Such an influence is likely in the cross-section of the planned monitoring station, therefore, a thorough preliminary analysis of the cross-sectional variation of the SSC was performed, based on expeditionary sediment measurement campaigns. Between 2018 and 2021 24 campaigns were carried out at different hydrological regimes, where physical sediment samplings together with fixed and moving boat ADCP measurements were performed. The cross-sectional variability of SSC and its influence on the sediment load estimations were assessed based on the moving boat ADCP measurements, after calibrating the backscatter signal with more than 500 physical samples. Based on the results, we identified different cross-sectional patterns of the SSC which is apparently governed by: (i) the actual hydrological situation considering both the main river and the tributary, and (ii) the local river morphology. Based on our findings, we suggested a correction method that accounts for the above effects, using which the near-bank SSC can be reliably converted into total suspended sediment load.

3

The potential impact of land use changes on heavy metal contamination in the drinking water reservoir catchment (Dobczyce Reservoir, south Poland)

Zemełka Gabriela, Kryłów Małgorzata, Szalińska van Overdijk Ewa

Archives of Environmental Protection

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2019

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Vol. 45, no. 2

3--11

EN

To investigate and assess the effects of land use and its changes on concentrations of heavy metals (Pb, Zn, Cd, Cu, Mn, Ni, Fe) in the tributary of drinking water reservoir catchment, soils of different land use types (forest, arable land, meadows and pastures, residential areas), suspended sediment and bottom sediment were collected. Heavy metals were analyzed using atomic absorption spectrophotometry (AAS). The metal distribution pattern was observed, where Zn and Cd could be considered as main metal contaminants. The variation in the concentration level of Zn and Cd in studied soils showed the impact of pollution from anthropogenic activities. Also some seasonal variations were visible among the suspended sediment and bottom sediment samples which could be associated with land agricultural practices or meteorological conditions. The sediment fingerprints approach used for determining sources of the suspension in the catchment showed (Kruskal-Wallis H test, p˂0.05), that only Mn and Ni were not able to be distinguished among the potential sediment sources. A multiple linear regression model described the relationship between suspended sediment and 4 types of soil samples. The results related suspended composition mostly to the samples from the residential land use. Considering the contemporary trend of observed changes in land use resulting in conversion of agricultural areas into residential and service structures these changes can be essential for the contamination of aquatic environment. This situation is a warning sign due to the rapid industrialization, urbanization and intensive agriculture in this region what can significantly affect the drinking water quality.

PL

Celem pracy była ocena wpływu użytkowania gruntów i ich zmian na stężenia metali ciężkich (Pb, Zn, Cd, Cu, Mn, Ni, Fe) w dopływie zlewni zbiornika wody pitnej. Do badań pobrano próbki gleb z różnych typów użytkowania gruntów (las, grunty orne, łąki i pastwiska, tereny zabudowane), rumowiska unoszonego oraz osadów dennych. Metale ciężkie oznaczono za pomocą Atomowej Spektroskopii Absorpcyjnej (ASA). W badanych próbkach zaobserwowano zmienność stężeń metali w zależności od sposobu użytkowania gruntów. Otrzymane wyniki świadczą również, że główne zanieczyszczenie metaliczne w zlewni stanowią Zn i Cd. Wśród próbek rumowiska unoszonego oraz osadów dennych widoczne były pewne wahania sezonowe, które mogły być związane z działalnością rolniczą lub warunkami meteorologicznymi. Zastosowana do określania źródeł zawiesiny w zlewni metoda sediment fingerprints (test Kruskal-Wallis H test, p˂0.05), ) wykazała, że spośród badanych metali jedynie Mn i Ni nie umożliwiają rozróżnienia potencjalnych źródeł pochodzenia rumowiska unoszonego. Pozostałe metale zostały zatem wykorzystane do opisania zależności między rumowiskiem a 4 typami próbek gleb za pomocą modelu regresji wielokrotnej. Model ten wykazał związek zanieczyszczenia próbek rumowiska metalami z zanieczyszczeniem gleb z terenów zabudowanych. Biorąc pod uwagę zaobserwowany współczesny trend zmian w użytkowaniu gruntów, prowadzący do przekształcania obszarów rolniczych w obszary mieszkalne i usługowe, może on istotnie wpływać na zanieczyszczenie środowiska wodnego i jakość wody pitnej. Taka sytuacja jest znakiem ostrzegawczym ze względu na szybkie uprzemysłowienie, urbanizację i intensywną gospodarkę rolną w tym regionie.

4

Modelling of the silting up of navigation channels

Kaczmarek L. M.

Technical Sciences / University of Warmia and Mazury in Olsztyn

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2008

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nr 11

175-187

EN

A mathematical model describing transport of non-uniformly graded sediments has been applied to analyzing the silting up of approach routes (navigation channels) leading to ports. This model distinguishes three layers in the movement of sediments, assuming that the vertical sorting occurs only in the process of picking up grains in the contact layer. It is also assumed that along the widnward edge of the route sediments are transported in the bedload and contact layers during the wave crest phase and - as suspended sediments - in the outer region under the influence of the resultant current. On the leeward side sediments are transported only during the wave trough phase in the bedload and contact layer. The computations have demonstrated that the above model can be a useful tool for predicting both the rate and volume of sediments silting up navigation channels as well as grain-size distribution of sediments which fill up a water route.

PL

Model matematyczny transportu osadów niejednorodnych granulometrycznie zastosowano do analizy zapiaszczania torów podejściowych (kanałów nawigacyjnych) do portów. Wyszczególnia on trzy warstwy ruchu osadów, przy czym założono, że pionowe sortowanie odbywa się tylko w procesie podrywania ziaren w warstwie kontaktowej. Zakłada się, że na krawędzi nawietrznej toru osady transportowane są w fazie grzbietu fali w warstwie wleczenia i kontaktowej oraz zewnętrznej - w formie zawieszonej - pod wpływem wypadkowego prądu. Na krawędzi zawietrznej osady transportowane są tylko w fazie doliny fali w warstwie wleczenia i kontaktowej. Przeprowadzone obliczenia pokazują, że zastosowany model może być użytecznym narzędziem w predykcji zarówno wielkości i tempa zapiaszczania, jak i określaniu rozkładów granulometrycznych osadów wypełniających tor wodny.