Groundwater supplies a significant proportion of water use in the United States and is critical to the maintenance of healthy ecosystems and environmental processes, thus characterizing aquifer ...hydrology is important to managing and preserving these resources. While groundwater isotopes provide insight into hydrologic and ecologic processes, their application is limited to where measurements exist. To help overcome this limitation, we used the random forest algorithm to develop a predictive model for shallow groundwater isotopes in the conterminous United States. Our model uses environmental variables (e.g. temperature, elevation, precipitation isotopes) as predictors. We used our model to develop the first shallow groundwater isoscape of δ2H and δ18O for the conterminous United States. We describe the patterns in groundwater isotopes using both observations and our modelled isoscape. We find that throughout much of the Eastern United States, groundwater isotopes are close to annual amount weighted precipitation, while groundwater isotopes are significantly depleted relative precipitation across much of the High Plains and Western United States. Furthermore, we compare the observations compiled for this study to isotopes of precipitation, which allows us to determine the relative recharge efficiency (i.e. ratio of groundwater recharge to precipitation) between seasons and the proportion of annual recharge that occurs in a given season. Our findings suggest that winter recharge is generally more efficient than summer recharge; however, the dominant recharge season is more varied as it is the product of both seasonal recharge efficiency and the seasonal timing of precipitation. Parts of the central United States have summer dominant recharge, which is likely the result of heavy summer precipitation/nocturnal summer precipitation. Interestingly, parts of coastal California appear to have summer dominant recharge, which we suggest could be due to recharge from fog‐drip. Our results summarize spatial patterns in groundwater isotopes across the conterminous United States, provide insight into the hydrologic processes affecting shallow groundwater, and are valuable information for future ecologic and hydrologic studies.
Stable isotopes of water (δ2H and δ18O) provide information on the water source and the hydrological processes that affect it as it moves through the hydrosphere. Here, we developed the first isoscape of groundwater δ2H and δ18O for the conterminous United States based on a random forest model using environmental variables as predictors (figure). We also calculated the seasonal recharge efficiency and proportion for several 1000 locations and used these results to make inferences on the hydrologic and environmental processes that affect groundwater systems across the United States.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
The present study collated data on the Indian blue carbon repository (mangroves, seagrasses, and salt marshes) from peer-reviewed literature on carbon stock assessment. This meta-analysis indicated ...that the blue carbon ecosystems of India could have a collective carbon stock of 67.35 Tg C (mangroves, seagrass, and salt marsh accounting for 67 Tg C, 0.0630 Tg C, and 0.0049 Tg C, respectively). Several studies have ubiquitously measured the spatial extent of mangroves (~ 4991 km
2
) and seagrasses (~ 517 km
2
) in India; however, the salt marshes (290–1398 km
2
) have contradictions in estimates. The green payments against the blue carbon ecosystems of India can be as high as ~ 9.6 billion US $, whereas the social cost of carbon sequestered by these ecosystems can vary between 0.47 and 5.43 billion US $. The present study also identified the key research areas that require priority to minimize the uncertainties in blue carbon stock assessment to foster a robust ecosystem-based approach for climate change adaptation in the country. The study identified that less than half of the total mangrove habitats of India are yet to be sampled leaving a scope of substantial uncertainty in nationwide blue carbon estimates. The spatial extent of India’s salt marshes is another aspect that needs to be delineated with a higher confidence level.
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CEKLJ, EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
Water extraction for anthropogenic use has become a major flux in the hydrological cycle. With increasing demand for water and challenges supplying it in the face of climate change, there is a ...pressing need to better understand connections between human populations, climate, water extraction, water use, and its impacts. To understand these connections, we collected and analyzed stable isotopic ratios of more than 800 urban tap water samples in a series of semiannual water surveys (spring and fall, 2013–2015) across the Salt Lake Valley (SLV) of northern Utah. Consistent with previous work, we found that mean tap water had a lower 2H and 18O concentration than local precipitation, highlighting the importance of nearby montane winter precipitation as source water for the region. However, we observed strong and structured spatiotemporal variation in tap water isotopic compositions across the region which we attribute to complex distribution systems, varying water management practices and multiple sources used across the valley. Water from different sources was not used uniformly throughout the area and we identified significant correlation between water source and demographic parameters including population and income. Isotopic mass balance indicated significant interannual and intra‐annual variability in water losses within the distribution network due to evaporation from surface water resources supplying the SLV. Our results demonstrate the effectiveness of isotopes as an indicator of water management strategies and climate impacts within regional urban water systems, with potential utility for monitoring, regulation, forensic, and a range of water resource research.
Key Points:
Tap water isotopes reflect urban water system structure and management practices
Isotopic patterns linked to political boundaries and demographic factors across Salt Lake Valley
Evaporation from city water sources increased by >9400 m3/day during unusually warm, dry years
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Upper Indus Basin (UIB) streamflow originates largely from glacier and snow melt in the upstream Himalaya, Karakoram, and Hindu Kush mountain ranges and is extremely vulnerable because of its ...projected climate changes, dense populations, and hydropolitical tensions. Accurate knowledge of streamflow constituents is required for resilient water resources management; this is precluded by a paucity of measurement as well as climatological and topographic complexity. Here we integrate citizen scientist acquired geochemical samples, collected from October 2018 through September 2019 in the Shimshal watershed of the Karakoram Mountains of Pakistan, with Sentinel‐1 (S1) synthetic aperture radar (SAR)‐derived wet snow maps, to better understand streamflow constituents for the high altitude and heavily glaciated catchment. We use Bayesian end‐member mixture analysis to separate river flows into baseflow and meltwater constituents, using fixed and time‐variant melt end‐member values. We compare river hydrograph separation results with S1 wet snow time series maps for the same timeframe. We then utilize S1 imagery to inform end‐member mixture analysis to separate meltwaters into snow and glacier melt. For the Shimshal catchment, we find that about 85% of annual river flows are derived from snow and glacier melt; 45% of annual flows are derived from snow melt and 40% glacier melt. Engaged and committed citizen scientists enabled geochemical sample collection and analysis on a significant temporal and spatial scale. In the future, co‐produced knowledge that both implements local expertise and that is also planned and utilized by diverse stakeholders may increase climatological awareness and resilience in the UIB.
Plain Language Summary
The Indus River Basin is home to about 300 million people that rely on streamflow for their livelihoods. Streamflow in the Indus is largely derived from snow and glacier melt from upstream mountain ranges. As populations increase and climate changes, understanding the role of snow and glacier melt in Indus streamflow is important for water resources management. Because of the rugged and remote nature of these mountain ranges, these important factors are not well understood. In this study, we work with local citizens in the Karakoram Mountains of Pakistan, who collected water samples from October 2018 through September 2019. We analyze these samples to better understand the role of meltwater in streamflow. We find that about 85% of streamflow is derived from snow and glacier meltwater. We also incorporate satellite remote sensing to better understand the role of snow versus glacier melt in streamflow. Snowmelt contributes 45% to streamflow; glacier melt contributes 40%. Improved knowledge of the role of snow and glacier melt in streamflow is important for sustainable water resources management in an area that is extremely vulnerable to water scarcity. Working with citizen scientists may improve our understanding of important variables to understand climate change in the region.
Key Points
Citizen scientist acquired geochemical tracers are integrated with Sentinel‐1 synthetic aperture radar remote sensing to examine streamflow constituents
Meltwater provides about 85% of the annual hydrograph in the Shimshal catchment: 45% snowmelt and 40% glacier melt
Co‐produced knowledge holds the potential to address challenges with sparse climatological measurement in remote and rugged terrain
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
Public water supply systems (PWSS) are critical infrastructure that is vulnerable to contamination and physical disruption. Exploring susceptibility of PWSS to such perturbations requires detailed ...knowledge of supply system structure and operation. The physical structure of the distribution system (i.e., pipeline connections) and basic information on sources are documented for most industrialized metropolises. Yet, most information on PWSS function comes from hydrodynamic models that are seldom validated using observational data. In developing regions, the issue may be exasperated as information regarding the physical structure of the PWSS may be incorrect, incomplete, undocumented, or difficult to obtain in many cities. Here, we present a novel application of stable isotopes in water (SIW) to quantify the contribution of different water sources, identify static and dynamic regions (e.g., regions supplied chiefly by one source vs. those experiencing active mixing between multiple sources), and reconstruct basic flow patterns in a large and complex PWSS. Our analysis, based on a Bayesian mixing model framework, uses basic information on the SIW and production volumes of sources but requires no information on pipeline connections in the system. Our work highlights the ability of stable isotopes in water to analyze PWSS and document aspects of supply system structure and operation that can otherwise be challenging to observe. This method could allow water managers to document spatiotemporal variation in flow patterns within PWSS, validate hydrodynamic model results, track pathways of contaminant propagation, optimize water supply operation, and help monitor and enforce water rights.
Urban water - a new frontier in isotope hydrology Ehleringer, James R.; Barnette, Janet E.; Jameel, Yusuf ...
Isotopes in environmental and health studies,
07/2016, Volume:
52, Issue:
4-5
Journal Article
Peer reviewed
Isotope hydrology has focused largely on landscapes away from densely inhabited regions. In coming decades, it will become increasingly more important to focus on water supplies and dynamics within ...urban systems. Stable isotope analyses provide important information to water managers within large cities, particularly in arid regions where evaporative histories of water sources, vulnerabilities, and reliabilities of the water supplies can be major issues. Here the spatial and vertical understanding of water supporting urban systems that comes from stable isotope analyses can serve as a useful management tool. We explore this research frontier using the coupled natural-human landscape of the Salt Lake Valley, USA, with its greater than one million inhabitants. We first provide data on the stable isotope ratios of the hydrologic system's primary components: precipitation, incoming surface waters, and terminus waters in this closed basin. We then explore the spatial and temporal patterns of drinking waters within the urban landscape and the new opportunities to better link isotope ratio data with short- and long-term management interests of water managers.
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BFBNIB, GIS, IJS, KISLJ, NUK, PNG, UL, UM, UPUK
ABSTRACTA commonly wasted agricultural waste, pomegranate peel has attracted attention as a useful biomaterial with a wide range of potential uses. Fruit and vegetable wastes create environmental ...difficulties, as well as a loss of valuable biomass and a financial cost to enterprises, due to its high biodegradability. This study focuses on the extraction and characterization of cellulose from both the outer and inner layers of pomegranate peel. The cellulose extraction process involves a multi-step approach, encompassing delignification and mercerization. Fourier transform infrared spectroscopy (FTIR) revealed characteristic peaks associated with cellulose, confirming its presence in the extracted material. Field emission scanning electron microscopy (FESEM) depicted the morphological transformation of cellulose as non-cellulosic components were removed during the extraction process. Particle size analysis demonstrated that alkaline treatment reduced the cellulose particle size. X-ray diffraction (XRD) analysis indicated a significant increase in cellulose crystallinity due to the elimination of hemicellulose and lignin following the extraction process. The chemical composition analysis revealed that treated pomegranate peels contained higher cellulose content compared to their untreated counterparts. This study offers insightful information about the possible uses of pomegranate peel cellulose and its adaptability to a different application.
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Understanding and predicting the effect of global change phenomena on biodiversity is challenging given that biodiversity data are highly multivariate, containing information from tens to hundreds of ...species in any given location and time. The Latent Dirichlet Allocation (LDA) model has been recently proposed to decompose biodiversity data into latent communities. While LDA is a very useful exploratory tool and overcomes several limitations of earlier methods, it has limited inferential and predictive skill given that covariates cannot be included in the model. We introduce a modified LDA model (called LDAcov) which allows the incorporation of covariates, enabling inference on the drivers of change of latent communities, spatial interpolation of results, and prediction based on future environmental change scenarios. We show with simulated data that our approach to fitting LDAcov is able to estimate well the number of groups and all model parameters. We illustrate LDAcov using data from two experimental studies on the long‐term effects of fire on southeastern Amazonian forests in Brazil. Our results reveal that repeated fires can have a strong impact on plant assemblages, particularly if fuel is allowed to build up between consecutive fires. The effect of fire is exacerbated as distance to the edge of the forest decreases, with small‐sized species and species with thin bark being impacted the most. These results highlight the compounding impacts of multiple fire events and fragmentation, a scenario commonly found across the southern edge of Amazon. We believe that LDAcov will be of wide interest to scientists studying the effect of global change phenomena on biodiversity using high‐dimensional datasets. Thus, we developed the R package LDAcov to enable the straightforward use of this model.
We introduce a modified Latent Dirichlet Allocation model (called LDAcov) which allows for the incorporation of covariates, enabling statistical inference on the drivers of change of latent communities, spatial interpolation of results, and prediction based on future environmental change scenarios. We illustrate LDAcov using data from two experimental studies on the long‐term effects of fire on southeastern Amazonian forests in Brazil. We believe that LDAcov will be of wide interest to scientists studying the effect of global change phenomena on biodiversity using high‐dimensional datasets.
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FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
Abstract
Groundwater supports agriculture and provides domestic water for over 250 million people in the Bengal Basin. Here we investigate the source of groundwater recharge using over 2500 stable ...water isotope measurements from the region. We employ a Monte Carlo statistical analysis to find distributions of possible components of recharge by accounting for the variability of isotope ratios in each of the possible recharge sources. We find that groundwater recharge sources have shifted in the last decades with a ~50% increase in recharge from stagnant surface water bodies (mostly during the latter part of the dry season) and a relative decrease in contribution from direct infiltration of precipitation (which occurs mostly in the early monsoon). We attribute this shift to an increase in standing water in irrigated rice fields and ponds, and an increase in the downward hydraulic gradient during the dry season driven by pumping.
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