Optimizing Waterbird Conservation in Urban Reservoirs: A Phenology-Synchronized Water Level Management Framework for Biodiversity Enhancement

Artificial wetlands can play an important role in waterbird conservation due to habitat loss and degradation of natural wetlands. Urban reservoirs can harbor waterbird communities, but they usually have lower biological diversity than natural wetlands. However, the value of reservoirs for waterbird conservation in urban areas needs further exploration. Here, we surveyed the waterbird community in a water-level controlled reservoir of an urban area in southeastern Brazil. We evaluate the seasonal variation in species composition, richness, and abundance. Monthly samplings were carried out between July 2017 and February 2018, through a boat line transect. A total of 7762 waterbirds were recorded, belonging to 32 species and 16 families. There were significant differences in species composition and abundance between dry and rainy seasons. The community was dominated by generalist and resident species, which Gallinula galeata and Jacana jacana were the most abundant species. We did not register migratory shorebirds during the surveys. Our results highlight the importance of reservoirs in urban areas, as they harbor feeding areas and breeding sites and may serve as refuges during dry seasons for resident waterbirds. We suggest management strategies to improve the importance of water-level controlled reservoirs as breeding areas for resident species and migratory stopover for shorebirds. Our results may also be considered for urban planning and waterbird conservation in urban areas.

Flood forecasting in urban reservoir using hybrid recurrent neural network

Water contamination greatly impacts human health. The Metropolitan Area of the Valley of Mexico (MAVM) is one of the most densely inhabited and polluted places globally, with a significant problem being the rising water demand. The research aims to assess the impact of metals such as iron, aluminum, lead, cadmium, and total chromium, among others, in the water of the Madin Dam, a key reservoir in the area's water supply. The assessment concentrated on individuals who were in good health and had been exposed to these pollutants. It analyzed factors such as levels of oxidized proteins; changes in the function of antioxidant enzymes (superoxide dismutase, catalase, and glutathione peroxidase); and their genetic expression, the occurrence of micronuclei, and the amount of DNA methylation. The findings were linked to the metals present in the MAVM drinking water, and the risk was evaluated. The research included four groups: two associated with the Madin Dam, consisting of persons living nearby or using water from the reservoir, and two acting as a control. The study highlighted a significant link between long-term exposure to pollutants in drinking water and elevated levels of oxidized proteins, increased micronuclei frequency, changes in antioxidant enzyme activity and gene expression, and a higher percentage of 5-methylcytosine. The risk assessment showed that people who use drinking water and/or consume fish from Madin Dam have a potential higher risk associated with metal contamination.

Reservoir water quality can be compromised by algal production and anoxia, which in turn are impacted by hydrodynamic stability and water temperature. We developed a conceptual model to quantify the dominant controls on stability, anoxia, and transparency using statistical analysis of a long-term (1990–2011) data set for four reservoirs in San Diego, California, each receiving runoff from a watershed with a different level of urban and agricultural land use. We hypothesized that water depth, not air temperature, controlled stability and that anoxia, after correcting for stability, increased and transparency decreased with increasing land use. Depth fluctuated widely interannually and was the dominant control on stability, which in turn controlled transparency in shallow reservoirs. Shallow depth and low stability correlated with low transparency. Transparency decreased with increasing development in the watershed. Water quality deteriorated over time in the reservoirs with the most and, contrary to our hypothesis, least developed watersheds. Deterioration of water quality in the pristine watershed coincided with the introduction of forage fish, which can suppress zooplankton density and translocate phosphorus to the photic zone. The interaction of land use, climate, water level management, basin morphology, and aquatic food webs can deteriorate water quality, even in reservoirs receiving runoff from pristine watersheds.

Filamentous cyanobacteria have been observed to become the dominant species in reservoirs, especially in small reservoirs for drinking water supply in southern China. The occurrences of filamentous cyanobacteria blooms in such reservoirs add additional costs for water plants by decreasing the filtration efficiency and the potential of toxin production. To serve the purpose of drinking water supply, the effective risk assessment requires the dynamic pattern of filamentous cyanobacteria. This study seasonally collected samples from 25 reservoirs in Dongguan, one of the most important 'world factories' in China in July, December and March, and investigated the temporal dynamics of phytoplankton, particularly cyanobacteria community. Our investigation showed that filamentous cyanobacteria, Planktothrix sp, Limnothrix sp. and Cylindrospermopsis raciborskii dominated in these reservoirs and climate-related water temperature was the primary factor for the seasonal shift of filamentous cyanobacteria. High abundance of filamentous cyanobacteria occurred in the high water level period with increasing temperature but less relevant with nutrient conditions. Our study observed the seasonal dynamics of filamentous cyanobacteria in tropical urban reservoirs and highlighted the association between temperature and filamentous cyanobacteria. our data and analysis provided an evidence that increased temperature could increase the likelihood of frequency and intensity of filamentous cyanobacteria blooms. In the scenario of global warming, more frequent monitoring of filamentous cyanobacteria and the potential to produce toxin should be considered for water quality and reservoir management.

Boreal peatlands strongly affect the global climate system by providing an important store for carbon (C) cycle and a natural source of methane. Over the past century, however, vast areas of natural peatlands have been drained to gain productive land, turning them into large potential C sources. Currently, there is a scientific debate on how to best manage historically drained boreal peatlands to improve their function in climate change mitigation. To investigate this, we conducted a climate chamber mesocosm experiment to assess the effects of climate change and water level (WL) management on GHG emissions. Three WL managements: low, medium, and high WL (rewetting) were simulated under both present (2022 growing season) and a moderate future climate scenario, RCP 4.5. The observed biweekly GHG fluxes from the mesocosm experiment were used as inputs into a radiative forcing (RF) model to assess the cooling/warming effect of different strategies. The results revealed that WL management had a significant effect on peatland CH4 emissions, while climate change had not. High WL management increased CO2 sink capacity through Sphagnum moss restoration, while low and medium WL managements decreased it. RF modelling suggested that high WL management under both present and future climates, and medium WL under future climate, have the potential to result in a long-term shift from a C source to a sink under favourable conditions. These strategies are suggested for their greater climate benefit potential. Our study highlights the need to consider WL-climate interactions for better predicting peatland GHG mitigation potential.

One of the most important factors that influences the performance of geomorphologic parameters on urban lakes is the water level. It fluctuates periodically, causing shoreline changes. It is especially significant for typical environmental studies like bathymetric surveys, morphometric parameters calculation, sediment depth changes, thermal structure, water quality monitoring, etc. In most reservoirs, it can be obtained from digitized historical maps or plans or directly measured using the instruments such as: geodetic total station, GNSS receivers, UAV with different sensors, satellite and aerial photos, terrestrial and airborne light detection and ranging, or others. Today one of the most popular measuring platforms, increasingly applied in many applications is UAV. Unmanned aerial system can be a cheap, easy to use, on-demand technology for gathering remote sensing data. Our study presents a reliable methodology for shallow lake shoreline investigation with the use of a low-cost fixed-wing UAV system. The research was implemented on a small, eutrophic urban inland reservoir located in the northern part of Poland—Lake Suskie. The geodetic TS, and RTK/GNSS measurements, hydroacoustic soundings and experimental aerial mapping were conducted by the authors in 2012–2015. The article specifically describes the UAV system used for experimental measurements, the obtained results and the accuracy analysis. Final conclusions demonstrate that even a low-cost fixed-wing UAV can provide an excellent tool for accurately surveying a shallow lake shoreline and generate valuable geoinformation data collected definitely faster than when traditional geodetic methods are employed.

Introduction: Fluoride is one of the naturally occurring mineral elements which has an effective role in preventing dental caries and its consolidation. Fluoridation of water is a simple technique and the most effective method approved for preventing dental caries. Accordingly, this research was carried out with the aim of investigating the level of fluoride in the urban water of cities in Western Azerbaijan province in 2017. Materials and Methods: In this descriptive-cross-sectional study, the level of fluoride in urban water reservoirs of 17 towns of Western Azerbaijan province was examined in different reservoirs. The information of the reservoirs was collected from water and wastewater organization of the province, where a 250-cc water sample was collected from each reservoir. The prepared samples were thenT sent to the laboratory to measure the level of fluoride. Determination of the concentration of fluoride ion in water samples was carried out using spectrophotometric method. Eventually, the data obtained from this study were examined by statistical-descriptive methods using SPSS 17. P <0.05 was considered as statistically significant. Results: The results obtained from the study indicate that the level of fluoride in the samples investigated in Shooth and Poldasht town was larger than the optimum level, while the rest of towns had a level lesser than the optimum value. Furthermore, the median of the investigated population (the median fluoride of the towns of Western Azerbaijan province) was 0.227 ppm, when based on statistical tests, it had a significant difference with the optimal fluoride value (1 ppm) (p-value<0.05). Conclusion: Considering the median of fluoride concentration in towns of Western Azerbaijan province (0.227 ppm), it can be stated that the level of fluoride in drinking water of this province is low, elucidating the addition of supplementary fluoride to the drinking water of reservoirs.

Water level (WL) fluctuations substantially alter the fauna, flora, and microbial community of nearshore aquatic ecosystems. Water level management therefore has the potential to strongly influence a wide variety of ecosystem processes. Many northern temperate lake food webs experience substantial methylmercury contamination, which is partially mediated by the action of sulfate‐reducing bacteria occurring in sediments that are periodically inundated. For lakes with elevated methylmercury, WL management could be designed to reduce methylmercury contamination. At the lake scale, this concept is supported by studies that identified statistical associations between fish mercury content and water level (WL) fluctuations. Here, we compiled a long‐term dataset (1997–2015) of mercury content in young‐of‐year Yellow Perch (Perca flavescens) from six lakes on the border of the United States and Canada and examined whether mercury content was associated with WL fluctuation. Many WL metrics covary and appear to have strong associations with Yellow Perch mercury. However, these associations appear to vary by lake, and lake‐specific models are needed to identify relationships between WL fluctuation and Yellow Perch mercury content. We used partial least‐squares regression (PLSR) to identify the associations between Yellow Perch mercury content and WL metrics, temperature, and annual deposition data for lakes in northern Minnesota. These PLSR models not only showed some variation among lakes, but also supported strong associations between WL fluctuations and annual variation in Yellow Perch mercury content. The study lakes underwent a change in WL management in 2000, when winter WL minimums were increased by about 1 m in five of the six study lakes, which reduced annual WL fluctuation on those lakes. Using the PLSR models, we estimated how this change in WL management would have affected Yellow Perch mercury content. In four of the five study lakes in which annual WL fluctuation was reduced in 2000, the change in WL management likely reduced Yellow Perch mercury content, relative to the previous WL management regime.

Water-level fluctuations are among the major driving forces for shallow lake ecosystems. In the low-lying parts of the Netherlands, the water-level regime of lakes is strictly regulated. This is needed for reducing risks of flooding and economic purposes, including maximum agricultural benefit. The fixation of water levels has had a severe impact on the functioning of (semi-)aquatic ecosystems. We review the benefits of natural water-level fluctuations, considering the impacts on nutrient inputs, nutrient concentrations, phytoplankton development and turbidity. In particular, the mediating role of submersed and emergent vegetation and filter feeders is addressed. The present government policy, to allow more space for water, presents a major challenge for combining flood prevention measures and ecological restoration. Restoration of natural water-level regimes, which is likely to lead to enhancement of water quality and biodiversity, may occur in two ways: (1) expanding the critical limits between which the water level is allowed to fluctuate annually, and/or (2) incidental recessions of the water level. It is stressed that ecologically-based water-level regimes should be incorporated into the context of multiple use of lakes.

The survival of waterbirds depends heavily on habitat, particularly aquatic plants. For each kind of aquatic plant, there are specific water level regime requirements to meet its germination and growth. Previous studies usually focused on the use of water level management to achieve protection and restoration of aquatic plants. However, the water level regimes in many wetlands have been greatly changed and their ecological objectives usually cannot be achieved by water level management alone. Accordingly, this study combined water level management and artificial planting for waterbird habitat provision in wetlands. The Hongze Lake National Wetland Nature Reserve was taken as the research area. In this study, we considered the needs of waterbirds for nesting and foraging, and determined the aquatic plant species to be planted. According to the seasonal water level requirements of these plants, we simulated the plantable areas of different aquatic plants under different water level regimes. We then further optimized the water level regimes according to the needs of waterbirds, and determined the optimal water level management scheme. In addition, we formulated planting principles, explored the planting structure under each water level regime, so that the plant structure can better serve the waterbirds. The results showed that the current water level regime of Hongze Lake is not consistent with the growth rhythm of aquatic plants. Because of the human regulation, the water level of the wetland is high in winter and low in summer, which is contrary to the requirements of aquatic plant growth. A combination of water level regimes and plant structure management, however, could effectively expand the area for waterbird habitat. The results of this study will help wetland managers to make informed decisions about how to restore the waterbird habitat in other similar regulated wetlands.

Floods are the most common naturally occurring catastrophic event that severely affects different types of land-cover structures in a river basin. This is due to climate change, which induces an increase in precipitation, which further leads to peak discharge during the monsoon season. This establishes the need for analyzing the rainfall trend and quantifying the temporal change in inundation area for flood resilient management. The study focuses on the use of microwave signals and their backpropagation technique through Space-based sensors like Synthetic Aperture Radar (SAR) for precisely detecting water pixels over the Western River basins of India. Urban areas and reservoirs are the major factors that need to be monitored as they affect the hydrological cycle of the basin. The Sentinel-1 SAR sensor equipped with C-band data is used for different temporal periods for mapping the change in flooding regions over major cities and the change in water extent of major reservoirs in the western river basins. In this study, a cloud computation image processing platform, Google Earth Engine, is used for rainfall trend analysis, the pre-processing of Sentinel-1 data, and mapping inundation extent. The research focuses on analyzing major Reservoirs and Vadodara City in Mahi River Basin located in the north-western region of India. The results were refined by Otsu thresholding, speckle filtering, removing semi-permanent water pixels, and steep slope regions to effectively delineate actual flooded pixels. Validation of the estimated water pixels by Sentinel-1 is done using CWC water level data and manual thresholding of the Modified Normalized Difference Water Index (MNDWI). The difference between Pre-flood and Post flood images of Vadodara City is done through the interferometric coherence technique, which measures the degree of correlation between both images to detect floodwater. The study’s flood inundation outputs were used to create a Flood Extent Database, which can be integrated with hourly rainfall to assess the rainfall-inundation relationship within the basin, and high-resolution SAR data to effectively map and identify the flooded pixels.

Two case studies were considered where gravity field changes were detected resulting from water mass variations. The first case is an urban water reservoir where the maximum daily change of water is 40000 m3. The 3D model of the water mass allowed us to build an accurate polyhedral model of the variation of mass changes of the water. This mass density variation model made it possible to compute and compare variations of various gravitational field functionals. Gravity and full gravity gradient tensor changes were computed on a regular grid for the model area. Gravity changes were also compared with actual gravity field measurements made with two LaCoste & Romberg (LCR) gravimeters. The measured gravity change was nearly 30 μGal relative to 5000 m3 water mass. A good agreement was found between the computed and measured changes. The second case is the water level fluctuations of the Danube River in Budapest during the great flood in 2002. In this case also modelling and measurements were compared. We found the gravitational change to be very sensitive to the actual distance of the point from the river bank.

BackgroundWater level management has been suggested as a potential tool to reduce malaria around large reservoirs. However, no field-based test has been conducted to assess the effect of water level management on mosquito larval abundance in African settings. The objective of the present study is to evaluate the effects of water level drawdown rates on mosquito larval abundance.MethodsTwelve experimental dams were constructed on the foreshore of the Koka Dam in Ethiopia. These were grouped into four daily water drawdown treatments, each with three replicates: no water-level drawdown (Group 1; Control), 10 mm.d-1 (Group 2), 15 mm.d-1 (Group 3) and 20 mm.d-1 (Group 4). Larval sampling was conducted weekly for a period of 6 weeks each in the main malaria transmission season (October to November 2013) and subsequent dry season (February to March 2014). Larval densities were compared among treatments over time using repeated measures Analysis of Variance (ANOVA).ResultsA total of 284 Anopheles mosquito larvae were collected from the experimental dams during the study period. Most (63.4%; n = 180) were collected during the main malaria transmission season while the remaining (36.6%; n = 104) were collected during the dry season. Larvae comprised four Anopheles species, dominated by Anopheles arabiensis (48.1% of total larval samples; n = 136) and An. pharoensis (33.2%; n = 94). Mean larval density was highest in control treatment dams with stable water levels throughout the study, and decreased significantly (P < 0.05) with increasing water drawdown rates in both seasons. During the main transmission season, anopheline larval density was generally lower by 30%, 70% and 84% in Groups 2, Group 3 and Group 4, respectively, compared with the control dams (Group 1). In the dry season, larval density was reduced by 45%, 70% and 84% in Groups 2, Group 3 and Group 4, respectively, when compared to the control dams.ConclusionIncreased water drawdown rates were associated with lower mosquito larval abundance. Water level management could thus serve as a potential control measure for malaria vectors around reservoirs by regulating the persistence of shallow shoreline breeding habitats. Dam operators and water resource managers should consider incorporating water level management as a malaria control mechanism into routine dam operations to manage the risk of malaria transmission to human populations around reservoirs.

Engineered water level management facilitates recruitment of non-native common carp, Cyprinus carpio, in a regulated lowland river