Search Results (18)

During heavy rainfalls, overflowing sewage water flows from the Combined Sewer Overflow (CSO) chambers and pollutes the Trnávka River in Trnava, Slovakia. This paper aims to propose water retention measures for the Trnávka River as a remediation technique for CSO-affected watercourses, which can contribute to the ‘flushing’ of the riverbed. During heavy rainfalls, the Trnávka River is polluted by solid, non-soluble materials, which produce unpleasant odors and are the subject of numerous complaints by citizens, particularly during low water levels. Three inflatable rubber weirs were designed, and their design was verified using a 1D numerical model of the Trnávka River. The simulations of the proposed measures performed in the HEC-RAS 5.0 software excluded the adverse effect of the backwater on the functioning of the CSO chambers in the city of Trnava during normal flow rates and confirmed that, even after installation of the weirs, the transition of the flood wave will pass in the riverbed, not causing the flooding of the adjacent area. The chemical–physical study of the Trnávka River confirmed our assumption that higher flow rates, which can be secured by the regulation of the proposed weirs, can contribute to the purity of the watercourse in the city of Trnava. Full article

Fish farming is increasingly important globally and nationally, playing a crucial role in fish production for human consumption. Monitoring microbiological and chemical contaminants from water discharge is essential to mitigate the risk of contaminating water and fish for human consumption. This study analyzes the physicochemical and E. coli parameters of water and tambacu fish muscles (Colossoma macropomum × Piaractus mesopotamicus) in Western Maranhão, Brazil. It also includes a qualitative characterization of zooplankton in the ponds. Samples were collected from tambacu ponds in a dam system fed by natural watercourses from the Tocantins River tributaries, located at the connection of the Brazilian savanna and Amazon biomes. The physicochemical and E. coli parameters of water did not meet national standards. The zooplankton community included Rotifera, Cladocera, Copepoda, and Protozoa representatives, with no prior studies on zooplankton in the region, making these findings unprecedented. The biological quality of freshwater is crucial in fish farming, as poor quality can lead to decreased productivity and fish mortality, raising significant food safety concerns. The water quality studied is related to the potential influence of untreated wastewater as a source of contamination, leaving the studied region still far from safe water reuse practices. The findings on chemical and E. coli contamination of fish farming waters concern human health and emphasize the need for appropriate regulations. Full article

Mercury contamination from gold mining in the Amazon poses significant environmental and health threats to the biome and its local populations. The recent expansion of non-industrial mining areas has severely impacted territories occupied by traditional communities. To address the lack of sampling data in the region and better understand mercury dynamics, this study used the probabilistic model SERAFM to estimate the mercury distribution and bioaccumulation in fish. The analysis covered 8,259 sub-basins across three major Amazonian basins: the Branco, Tapajós and Xingu rivers. The findings revealed increasing downstream mercury levels, with notable accumulations in the main watercourses influenced by methylation processes and mining releases. The projected concentrations showed that an average of 27.47% of the sub-basins might not comply with Brazilian regulations, rising to 52.38% in the Branco and Tapajós river basins separately. The risk assessment of fish consumption based on the projections highlighted high mercury exposure levels among traditional communities, particularly indigenous populations, with an average of 49.79% facing an extremely high risk in the Branco and Tapajós river basins. This study demonstrated SERAFM’s capacity to fill information gaps in the Amazon while underscoring the need for enhanced data collection, culturally sensitive interventions and regulatory updates to mitigate mercury contamination in gold mining-affected areas. Full article

Lake Baikal is the largest freshwater lake in the world, accounting for about 20% of the world’s fresh surface water. The lake’s outflow to the ocean occurs only via the Angara River, which has several hydroelectric power plants (HPPs) along its watercourse. The first such HPP, Irkutsk HPP, was built in 1956 and is located 60 km from the Angara River’s source. After two years, the backwater from this HPP expanded to the lake shores and began raising the Baikal Lake level. Currently, there is a dynamic balance between the new lake level, the lake inflow from its tributaries, and the Angara River discharge through the Irkutsk HPP. However, both the Angara River discharge and the Baikal Lake level were distorted by the HPP construction. Thus, to understand the changes to the lake basin over the past century, we first needed to estimate naturalized lake levels that would be if no HPP was ever built. This was an important task that allowed (a) the actual impact of global changes on the regional hydrological processes to be estimated and (b) better management of the HPP itself to be provided through future changes. With these objectives in mind, we accumulated multi-year data on the observed levels of Lake Baikal, and components of its water budget (discharge of main tributaries and the Angara River, precipitation, and evaporation). Thereafter, we assessed the temporal patterns and degree of coupling of multi-year and intra-annual changes in the lake’s monthly, seasonal, and annual characteristics. The reconstruction of the average monthly levels of Lake Baikal and the Angara River water discharge after the construction of the Irkutsk HPP was based on the relationship of the fluctuations with the components of the Lake water budget before regulation. As a result, 123-year time series of “conditionally natural” levels of Lake Baikal and the Angara River discharge were reconstructed and statistically analyzed. Our results indicated high inertia in the fluctuations in the lake level. Additionally, we found a century-long tendency of increases in the lake level of about 15 cm per 100 years, and we quantified the low-frequency changes in Lake Baikal’s water levels, the discharge of the Angara River, and the main lake tributaries. An assessment of the impact of the Irkutsk HPP on the multi-year and intra-annual changes in the Lake Baikal water level and the Angara River discharge showed that the restrictions on the discharge through the HPP and the legislative limitations of the Lake Baikal level regime have considerably limited the fluctuations in the lake level. These fluctuations can lead to regulation violations and adverse regimes during low-water or high-water periods. Full article

The paper deals with a proposal for a small-watercourse revitalization measure, which is currently regulated by a post-local treatment. The sections of the watercourse are relatively straight and direct. The current shape of the stream does not retain water in the landscape. Any surface water in the watercourse is quickly transferred to the receiving watercourse, which is the important Hvozdnice watercourse. The practical part includes the design of revitalization measures, a new longitudinal profile, and sections. The watercourse is loosened by curves and the total length of the watercourse has been extended by 161.56 m. The route includes a wetland, four pools, and two pond wedges. An economic estimate of the proposed measure was made. Full article

The aim of this study is to evaluate the occurrence of weeds under conditions of limited herbicide use due to the protection zone of water resources. A total of 23 weed species were found in maize stands, 19 species were found in wheat stands, and 16 species were found in rapeseed stands. The redundancy analysis (RDA) results show significant differences in weed occurrence and composition due to herbicide regulation in each crop. Changes in weed composition induced by herbicide application limitations lead to a preference for more specialized weed species (specialists) at the expense of widespread species (generalists). Limiting the use of pesticides in sensitive and vulnerable areas, such as water sources, bodies, and watercourses, is justified from the perspective of protecting the aquatic environment and biodiversity. However, such measures can cause weed growth that is difficult to control, and therefore, it is important to search for new methods for weed control in field crops. Determining a balance between safeguarding water resources and addressing agricultural challenges remains crucial for sustainable land and water management. Full article

A very noticeable increase in the beaver population (mainly the Eurasian beaver (Castor fiber L.)) in the East European Plain since the end of the 20th century through reintroduction contributed to the emergence of a large number of beaver dams and ponds, which resulted in the transformation of the channels and the hydrological regime of small rivers. In this paper, for the first time in the Middle Volga region, regularities in the distribution of beaver dams and ponds on small rivers were revealed based on a topographic survey of the river channel, regulated by beaver activity in recent decades. The materials of the paper were obtained during field (geodetic) work in August and September of 2022 in the valleys of two small rivers typical for the north of the Volga Upland, Morkváshinka River (16.6 km) and Morkváshka River (7.8 km), with subsequent statistical processing. According to the results obtained, all the dams we encountered were located in the sections of their channels with relatively small (up to 1%) and medium (1–3%) average gradients. In the upper reaches of the rivers, the expansion of beaver activity is limited to the large gradients of their channels. Along the entire length, there is an alternation of sectors with a “natural” (not regulated by beavers) channel and a cascade of beaver ponds. Drained (at the time of the survey) sectors without dams, as well as those with preserved and destroyed dams, were also identified on the Morkváshinka River. On the whole, 26–48% of the length of the studied rivers has been transformed by beaver activity. The average number of dams per kilometer of the watercourse is 3.7–5.1. The most favorable channel gradients for beaver activity are 3.6–16.6 m/km, or 0.36–1.66%. The average gradient of the channel, above which no beaver dams and related ponds were found in these rivers, is 30 m/km, or 3%. An increase in the channel gradient upstream of the rivers is reflected in the size of beaver dams and ponds. The beaver dams and ponds are slightly larger in the sections of the rivers with a relatively small average gradient than in the sections with a medium average gradient of the channel. Full article

Loss of body armour, sometimes including a reduction in or loss of pelvic spines, is an adaptation observed in many isolated freshwater populations. Pelvic reduction in sticklebacks has previously been associated with recurrent, but variant, deletions within pelvic enhancer regions PelA and PelB, which regulate expression of the homeodomain transcription factor gene Pitx1. We investigated variation in nucleotide sequences of pelvic enhancers in sticklebacks collected from two small freshwater lakes in the same watercourse and a nearby marine site in subarctic Norway. Spineless, as well as asymmetrically spined and completely spined sticklebacks are present in the upper lake, while only specimens with complete spines are found at the other lake and the marine site. Observed variation at PelA between the three sites was mainly due to variable numbers of repeats at three fragile TG-repeat loci. The length of PelA, mainly at one of the TG-repeat loci, was consistently shorter among individuals in the upper lake compared with specimens from the two other sites. However, no obvious association was revealed between enhancer variants and pelvic status. No polymorphism was found at PelB. Thus, additional genetic factors and/or environmental cues need to be identified to fully explain the occurrence of pelvic reduction in sticklebacks in this lake. Full article

Human activities have caused a significant change in the function and services that ecosystems have provided to society since historical times. In mountainous landscapes, the regulation of services such as water quality or erosion control has been impacted by land use and land cover (LULC) changes, especially the loss and fragmentation of forest patches. In this work, we develop a Remote Sensing (RS)-based modelling approach to identify areas for the implementation of nature-based solutions (NBS) (i.e., natural forest conservation and restoration) that allow reducing the vulnerability of aquatic ecosystems to siltation in mountainous regions. We used time series Landsat 5TM, 7ETM+, 8OLI and Sentinel 2A/2B MSI (S2) imagery to map forest dynamics and wetland distribution in Picos de Europa National Park (Cantabrian Mountains, northern Spain). We fed RS-based models with detailed in situ information based on photo-interpretation and fieldwork completed from 2017 to 2021. We estimated a forest cover increase rate of 2 ha/year comparing current and past LULC maps against external validation data. We applied this forest gain to a scenario generator model to derive a 30-year future LULC map that defines the potential forest extent for the study area in 2049. We then modelled the distribution of wetlands to identify the areas with the greatest potential for moisture accumulation. We used an S2 mosaic and topography-derived data such as the slope and topographic wetness index (TWI), which indicate terrain water accumulation. Overall accuracy scores reached values of 86% for LULC classification and 61% for wetland mapping. At the same time, we obtained the potential erosion using the NetMap software to identify potential sediment production, transport and deposition areas. Finally, forest dynamics, wetland distribution and potential erosion were combined in a multi-criteria analysis aiming to reduce the amount of sediment reaching selected wetlands. We achieved this by identifying the most suitable locations for the conservation and restoration of natural forests on slopes and in riparian areas, which may reduce the risk of soil erosion and maximise sediment filtering, respectively. The results show a network pattern for forest management that would allow for controlling erosion effects across space and time at three levels: one, by reducing the load that originates upslope in the absence of forest cover; two, by intersecting runoff at watercourses related to sediment transport; and three, by a lack of former barriers, by trapping erosion near to the receiving wetland systems, main river axes and contributing streams. In conclusion, the proposed methodology, which could be transferred to other mountain regions, allows to optimise investment for erosion prevention and wetland conservation by using only very specific areas of the landscape for habitat management (e.g., for NBS implementation). Full article

Pressures arising from agriculture, infrastructures and settlements have gradually reduced natural spaces of European watercourses limiting their self-regulation capacities, environmental and social potentials, resulting in widespread critical anthropic features. Dealing with flood phenomena adds artificiality, as several works for hydraulic protection are necessary. This was the case of Pistoia, a small city in the north of Tuscany, where the Ombrone stream, held in a straight-channeled course since the 18th century, sometimes breaks its embankments and floods the low plain from the southeast of Pistoia to downstream. Complying with the EU Floods Directive (2007/60/EC), the regional authority for flood risks planned some basins in the high plain upstream of Pistoia. A study we developed before this research assumed to shift the design approach from functional separation to full integration of hydraulic works in an area planned as an urban park for several years, but still in waiting. We now carried out a second study that adopts the concept of deep structure as the main design reference to “see” the park in the landscape features. This article concerns the research by the design process just developed to investigate a sustainable layout of the place new hydraulic asset as a basic landscape identity of the future park. Not to split spaces up with regard to their main functions was the general aim the process was focused on to combine an effective hydraulic protection with a full environmental and social enhancement of the urban park. Full article

The environmentally friendly concept in terms of water quality represents a condition for developing hydropower plants all around the world. Since 2017, hydropower has represented more than 70% of all renewable energy production and it is essential for the integration of the other renewable sources of energy and for regulation of the grid. To maintain the “green” label concerning the dissolved oxygen level (6 mg DO/L), the energy suppliers should respond to environmental concerns about the operation of hydropower plants. In the context of sustainable development, the ecological degradation of rivers is unacceptable due to the implementation of a hydropower plant on the watercourse. For deep reservoirs or tropical regions, the oxygen level in the water downstream of the hydropower plants may be low and affect the aquatic life for many kilometers downstream. This paper presents a new aeration system for discharged water from hydropower plants that provides water aeration with minimum energy consumption. The influence of the aeration process on the turbine operation and efficiency is analyzed. Experimental measurements are carried out on site on a small Francis turbine. The influence of the aeration process on the turbine mechanical performances (vibration level and relative displacement) and hydraulic performances (turbine efficiency, power output, and pressure fluctuation) is analyzed. The results showed that the impact of the aeration device implementation and operation over the energetic characteristics of the turbine is in the efficiency measurements accuracy range. The aeration through this device did not influence the turbine operation (vibration, level, or pressure fluctuations). Full article

The determination of minimum residual flow (MRF) follows diverse methodology in Europe due to differing hydrological conditions, ecosystem requirements, water abstraction requirements, and legislation. Methodologies in individual countries are difficult to compare qualitatively. However, individual approaches can serve as examples for countries undergoing the process of developing new methodologies, either for legislative purposes or to improve environmental standards on watercourses. This is exactly the situation in the Czech Republic which, has been working on the Regulation of the Government of the Czech Republic for ten years, since the amendment to the Water Act in 2010, defines the methods and criteria for determining the MRF on watercourses. T.G. Masaryk Water Research Institute, p.r.i., was commissioned to develop a new methodology to serve as the basis for the wording of aforementioned regulation. The new methodological approach took into account modern trends concerning the preservation of ecological standards, and used standard hydrological characteristics for its calculations. The newly proposed approach is undergoing a complicated approval process as the authors seek to increase the MRF compared to the current approach. The new approach assumes an MRF setting between $Q_{97}$ and $Q_{90}$. It defines four areas within the Czech Republic, by their hydrological and hydrogeological conditions, where the MRF is determined in different ways. This article describes the development of a new methodological approach, including the use the available Czech Hydrometeorological Institute data sets, the proposed regional division for MRF calculations, the determination the MRF below reservoirs, and the current state of the issue. Full article

The hydrological regime of the Iberian Peninsula is characterized by its extreme irregularity, including its propensity for periodic floods, which cause severe floods. The development of suitable cartographies and hydraulic models (HEC-RAS, IBER, etc.) allows for defining, with sufficient precision, the areas flooded by a determined return period, and for elaborating maps of danger and areas at risk of flooding, making it possible to adopt the corresponding preventive measures of spatial planning. These preventive measures do not avoid the need for contingent plans, such as the Civil Flooding Protection Plans. Many of the Peninsula’s watercourses and rivers are regulated by reservoirs built to ensure water supply and to smooth floods by releasing water in extreme hydrological climates. Hydrological modeling tools (rain/run-off) and Decision Support Systems DSS have been developed for the optimal operation of these dams in flood situations. The objective of the article is to study and prove the effectiveness of the integrated data provision in real time, while the event occurs—a circumstance that was not possible from the limited available meteorological stations available from Official Weather Services. The development of the Automatic Hydrological Information System (SAIH) in the Spanish River Basin Authorities (Confederaciones Hidrográficas), which includes a dense network of thermo-pluviometric stations and rain-river flow gauges, has allowed for new perspectives in order to realize an effective forecast method of flows during episodes of extreme precipitation. In this article, we will describe the integration of a hydrological modeling system, developed by the Confederación Hidrográfica del Tajo (River Authority), to meet the described objectives; the results of this methodology are novel. This allows for the processing of the 15-minute data provided, including the simulation of the snow accumulation/melting processes and the forecast of inflows to the reservoir to help in the establishment of safeguards and preventive waterflow releases. Finally, the methodology described is shown in a real case of study at Rosarito and El Burguillo Reservoirs. Full article

Inadequate management of water resources may generate various potential geohazard risks. To resolve potential risks, significant anthropogenic factors need to be engaged, such as human, material and financialcapacities. Fluvial erosion and soil erosion control are among the major problems that occur within an integrated water management system. These natural processes can be accelerated due to certain human activities: agricultural production, civil engineering and mining. Is there a comprehensive approach that would identify the problems at the early stages and minimize the necessary actions? The application of the geographic information system (GIS) within the modified Gavrilović model represents a step further towards systematic monitoring and regulation of watercourses in different parts of the basin. This case study provides an example of the early detection of hydrological problems that can occur in a river stream and a proposal for the solutions that would be imposed as the logical causality based key. The Likodra river basin is a representative example of the application of GIS for early detection and prevention of current water problems. Full article

To support decision-making, benefit assessments have become an obligatory part of natural resource management. In this context, the ecosystem services (ES) framework has been widely adopted for identifying and assessing the values at stake, yet the concept ignores benefits from water and land use functions as important contributions for societal welfare. This paper aims to contribute knowledge for improved benefit assessments in human-modified landscapes, exemplified by watersheds regulated for the production of hydropower. Through a case study approach in two regulated watersheds in Norway, beneficiaries’ perceptions of the benefits associated with key watershed activities, i.e., hydropower production, kayaking, angling, and hiking, are presented. Considering the beneficiaries’ perspectives, we discuss the relative ability of economic, quantitative, and qualitative assessment methods to present benefits. The study shows that benefit assessments must be carried out on different scales of governance, as benefits are context and scale dependent. We argue for an approach which considers a balance of benefits obtained from ecosystem services, and from water and land use functions within ecological limits. The suitability of the ES framework for guiding benefit assessments in a human-modified landscape and its complementarity with the sustainability concept for informing local-level decision-making are discussed. Full article