Aluminum in Bottom Sediments of the Lower Silesian Rivers Supplying Dam Reservoirs vs. Selected Chemical Parameters

The study was carried out on sediments collected from three rivers: Nysa Szalona, Strzegomka and Bystrzyca flowing in southwestern Poland. The content of Al in sediments and in bottom water was determined in relation to chemical conditions. The study was carried out in a four-year cycle, during spring and autumn. The aim of the study was to determine the level and accumulation of aluminum in sediments of rivers supplying dam reservoirs storing water for consumption. The sediments studied were mineral in nature, with neutral pH and moderate sulfate content. The level of Al and heavy metals in the sediments was the highest in the Nysa Szalona River and the lowest in the Strzegomka River, which was also evident in the concentration factor (CF). In terms of season, higher Al contents were recorded in sediments in autumn than in spring, which was also reflected in the concentration factor (CF). Along the course of the river, a gradual decrease in Al levels was observed in successive tributaries in the Nysa Szalona and Strzegomka Rivers, while there was no apparent regularity for the Bystrzyca. Against this background, a comparison of extreme sites below the springs and at the reservoir outlet shows that values were higher in the Nysa Szalona below the springs, and lower in the Strzegomka and Bystrzyca below the reservoir outlet. The general picture of Al and heavy metal loading of the studied sediments shows the lowest loading for the Strzegomka, only the enrichment factor (EF) was the lowest for the Nysa Szalona: metal pollution index (MPI)—S < B < NS, contamination factor (Cf)—S < B < NS, degree of contamination (DC)—S < NS < B, EF—NS < B < S, geoaccumulation index (Igeo)—S < B < NS, CF—S < NS < B. There was no effect of catchment size and river length on Al levels in sediments.

Inventory of Reservoirs of Key Significance for Water Management in Poland—Evaluation of Changes in Their Capacity

Dam reservoirs constitute an important element of protection against floods and hydrological droughts, and they ensure the possibility of producing electricity. Loss of reservoirs’ storage capacity has a significant impact on the management of their water resources, including flood protection and counteracting the effects of drought and the possibility of producing electricity. The paper presents changes in the capacity of 47 reservoirs in Poland that have the status of key objects of protection against floods and hydrological drought. Based on the collected, unpublished data, the changes in capacity from the beginning of the reservoirs’ existence to 31 March 2021 were calculated, which allowed us to determine the total amount of lost capacity and the pace of the processes taking place. From the beginning of operation (average operation time 48 years), the capacity has decreased by about 5%, which means that almost 200 million m3 less water is stored. Detailed analyses of the lost capacity also allowed for an illustrative presentation of forecasts for further changes in the short and long term. The results obtained represent a unique contribution to future national strategies for the management of sediment and reservoirs’ flood reserve and reduction of drought. The presentation of this problem seems to be important also in the context of climate change.

Using a Deflector and Crest Design to Make a Safe Spillway Operation

Floods are an important hazard throughout the world. The origins of some floods are a dam failure, hydraulic structure failure as well as an improper performance of the spillway. Among these, shaft spillways are known as a flood drainage system in dams, which is submerged by increasing the level of the reservoir, so that reduces the spillway efficiency and causes over topping. Investigations show that using deflector and aeration in shaft spillways will cause the flow pattern to improve. In this study, it has been tried to experiment on the impact of a deflector located in the throat and inlet geometry of the crest on the improvement of the hydraulic performance of the shaft spillway, and decrease to some extent the hazard induced by lack of timely drainage of floods in dam reservoirs. In order to investigate the deflector effect, three constriction specimens in shaft throat with constriction area to shaft area ratio (Ad/Ai) of respectively 0.75, 0.5 and 0.25 were considered as scenarios. In each scenario, the conditions of the flow passing through 12 different specimens of spillway with Crown Wheel inlets were tested and the results were compared with the flow conditions in crown wheel spillways without deflector (reference model). The results showed that the use of deflector has an important role in reducing vortex flows and stabilizing changes in the water level of the reservoir, and also increases the discharge coefficient of the flow. The studies on reference models also showed that Crown Wheel inlets (C.W.) improved shaft spillway performance, with C.W. spillways having an average discharge coefficient of 32% higher than shaft spillways. Finally, considering optimal deflector factors and C.W. geometry, an optimal model was proposed for flood reservoir conditions.

Evaluation of Phytoremediation Potential of Vetiver Grass (Chrysopogon zizanioides (L.) Roberty) for Wastewater Treatment

Water pollution is one of the most critical global issues. Meanwhile, the problem of water pollution of rivers especially in Iran is rising due to expansion of agricultural and industrial applications. Due to a large number of sewer catchments, there are some dam reservoirs like ZHAVE in Iranian state of Kurdistan that have not been able to collect significant amount of water since last 10 years. Removal of heavy metals as contaminants from runoffs and recycling of water is a necessity and a vital issue in the world. Various methods and standards are invented and used to isolate and remove all types of pollutants. This study focuses on the purification and removal of contaminants in water sources using the phytoremediation method by introducing Vetiver grass species in the case of floating treatment wetland (FTW). This study’s preliminary purpose is to investigate a practical remedial solution and improvement methodology for the water quality of reservoirs and rivers by growing the floating Vetiver island method. The results show that following parameters such as COD by 97%, TN by 90%, phosphorus by 66%, TDS by 26%, and evapotranspiration by 40% were reduced. Therefore, we concluded that for a wastewater with varying neutrient concentrations such as in ZHAVE dam, concentration of nutrients N and P was controlled and consequently inhibition and prevention of the eutrophication of water resources in the medium and long term became possible due to reduction in the rate of evaporation from reservoirs.

Application of Remote Sensing Technology in Sediment Estimating Entering the Dam Reservoirs due to Floods

The present study aimed to use remote sensing technology to estimate the concentration of particulate materials in the water entering the reservoirs of dams and consequently investigate the possibility of estimating the amount of sediment carried to the reservoir by flood during the life of the dam and its annual estimate. Using an advanced spectrometer device (ASD), the reflectance values of water containing different amounts of particulate sediments were measured in the range of 400–2500 nm; then, these reflectance values were represented for the Landsat 8 satellite OLI bands using their spectral response functions. In the study of interband correlation with the number of particulate materials, band 2 (blue) and band 5 (near-infrared) were identified to prepare a specific and appropriate model. The specificity of the reflectance difference in the two abovementioned bands was presented as an exponential relationship between the concentration of particulate materials and spectral reflectance. In this model, the RMSE parameter for the maximum possible sediment concentration was equal to 1.57 and the parameter R2 was equal to 0.91. In the second step, at the same time as the satellite passed, the area was visited and the sediments of the Ardak dam reservoir were sampled by recording their location. To complete this research, two measures were performed simultaneously, calculating the concentration of particulate materials sampled in the laboratory environment and their location on the image. Then, the number of particulate materials is estimated by taking into account the coordinates recorded from the images on which the relevant corrections have been made. According to the extracted exponential model, the results of estimating the concentration of particulate matter obtained from the model and Landsat satellite images with the concentration of particulate matter obtained from sampling showed its complete compatibility with field surveys to validate this research.