Surface Water Diversions Research Articles

Assessment of Parshall flumes for discharge measurement of open-channel flows: A comparative numerical and field case study

This paper presents a series of numerical and field studies to examine the accuracy of two field-scale Parshall flumes, which are employed to measure the flow rate of a wastewater system in the city of Minneapolis, Minnesota. The numerical studies were carried out using the large-eddy simulation (LES) and level-set methods to compute the turbulent flow of sewers under two-phase flow (wastewater and air) conditions. Flow rate measurements in the field were conducted using the dye dilution approach and an in-site flow measuring tool. Using the combination of field measurements and numerical simulations, this research aims at quantifying (i) the margin of error of the filed-scale Parshall flumes and (ii) the water surface fluctuations within the Parshall flumes. The LES turbulent model, coupled with the level-set method, allowed for resolution of instantaneous water surface variations and uncertainty quantification of the flow rate measurements.

Water storage and irrigation practices for cannabis drive seasonal patterns of water extraction and use in Northern California

There is growing concern over the impacts of cannabis farms on the environment and water resources in particular, yet data on cultivation practices and water use patterns have been limited. Estimates of water use for cannabis cultivation have previously relied on extrapolated values of plant water demand, which do not account for differences in cultivation practices, variation across the growing season, or the role of water storage in altering seasonal extraction patterns. The current study uses data reported by enrollees in California's North Coast Regional Water Quality Control Board Cannabis Program to model how variation in cultivation practices and the use of stored water affect the timing and amount of water extracted from the environment. We found that the supplemental use of stored water resulted in a seasonal pattern of water extraction (water withdrawals from the environment) that was distinct from water demand (water applied to plants). Although water input to storage in the off-season months (November through March) reduced water extraction in the growing season (April through October), farms generally did not have sufficient storage to completely forbear from surface water extraction during the growing season. The most important predictors of storage sufficiency were type of storage infrastructure, type of water source, and farm size, with the likelihood of sufficiency decreasing with increasing cultivation area. As of 2019, state cannabis regulations require forbearance from surface water diversions from April through October. To comply, farms relying on surface water must either develop storage, reduce water demand, or seek alternative water sources, such as groundwater. Our findings indicate that water extraction from farms using groundwater wells generally occurs during the summer dry season and highlight the need to assess their potential impacts to connected surface water in streams. Finally, given that the current study was based on data exclusively from permitted cannabis farms, additional data from unpermitted operations would enhance our overall understanding of cannabis water-use practices and consequences for the environment.

Interpretation of hydrogeochemical data using Hierarchical Cluster Analysis: A case study at Wadi El-Natrun, Egypt

Multivariate Statistical techniques have been widely applied in hydrogeology, geochemistry, and hydrology to identify commonalities or differences between large data sets. In this article, Hierarchical Cluster Analysis was performed on recent hydrogeochemical data (27 wells and 8 inland lakes) obtained at Wadi El-Natrun in April 2013 and April 2015. The purpose of this exercise was to understand the variability and similarities between ground and surface water quality in a less complex way. As well, to identify key variables in these environmental settings that could help to monitor the water quality of these resources. An additional purpose has been to shed some light, from a chemistry point of view, on the witnessed ‘salinization’ of these resources within this area. Overall, HCA provided an indication that both resources received had a potential water recharge during 2015 relative to 2013 that was supported by other regional reporting. Rearrangement of some surface water variables within clusters relative to groundwater was indicative of topsoil mineralization as well as the change in water levels due to recharge and/or evaporation.

Probabilistic Categorical Groundwater Salinity Mapping From Airborne Electromagnetic Data Adjacent to California's Lost Hills and Belridge Oil Fields

AbstractGrowing water stress has led to emerging interest in protecting fresh and brackish groundwater as a potential supplement to water supplies and raised questions about factors that could affect the future quality of fresh and brackish aquifers. Limited well infrastructure, particularly in regions where elevated salinity has led to limited historical groundwater development, hinders traditional mapping of salinity distributions through groundwater sampling. This paper presents a quantitative salinity mapping approach of the upper 300 m using high‐resolution, regionally comprehensive resistivity models derived from Bayesian inversion of an airborne electromagnetic survey adjacent to the Lost Hills and Belridge oil fields in the southwestern San Joaquin Valley of California. Using local water quality observations as an interpretational foundation, a probabilistic approach yields maps of fresh, saline, and brackish groundwater while quantifying joint uncertainty inherited from the geophysical data and interpretational relations. Saline and fresh regions are mapped with relatively high confidence in many locations, while areas of lower confidence, particularly at depth, can be mapped as their most probable salinity category while reflecting the relative uncertainty in the interpretation. These maps identify a stratified salinity structure, where saline water commonly occurs in the surficial aquifer overlying fresher groundwater in the Tulare aquifer, separated by regional confining clay layers. Downgradient of unlined surface water diversions, recharge of imported surface water results in relatively fresh groundwater throughout the depth of investigation.

Basin-scale multi-objective simulation-optimization modeling for conjunctive use of surface water and groundwater in northwest China

Abstract. In the arid inland basins of China, the long-term unregulated agricultural irrigation from surface water diversion and groundwater abstraction has caused the unsustainability of water resources and the degradation of ecosystems. This requires the integrated management of surface water (SW) and groundwater (GW) at basin scale to achieve scientific decisions which support sustainable water resource allocation in China. This study developed a novel multi-objective simulation-optimization (S-O) modeling framework. The optimization framework integrated a new epsilon multi-objective memetic algorithm (ε-MOMA) with a MODFLOW-NWT model to implement real-world decision-making for water resource management while pondering the complicated groundwater–lake–river interaction in an arid inland basin. Then the optimization technique was validated through the SW–GW management in Yanqi Basin (YB), a typical arid region with intensive agricultural irrigation in northwest China. The management model, involving the maximization of total water supply rate, groundwater storage, surface runoff inflow to the terminal lake, and the minimization of water delivery cost, was proposed to explore the trade-offs between socioeconomic and environmental factors. It is shown that the trade-off surface can be achieved in the four-dimensional objective space by optimizing spatial groundwater abstraction in the irrigation districts and surface water diversion in the river. The Pareto-optimal solutions avoid the prevalence of decision bias caused by the low-dimensional optimization formulation. Decision-makers are then able to identify their desired water management schemes with preferred objectives and achieve maximal socioeconomic and ecological benefits simultaneously. Moreover, three representative runoff scenarios in relation to climate change were specified to quantify the effect of decreasing river runoff on the water management in YB. Results show that runoff depletion would have a great negative impact on the management objectives. Therefore, the integrated SW and GW management is of critical importance for the fragile ecosystem in YB under changing climatic conditions.

Large-scale afforestation significantly increases permanent surface water in China's vegetation restoration regions

China is facing the challenge of the uncertain impacts of large-scale afforestation on regional water resources. However, the effects of vegetation cover changes on the variation in surface water at the regional scale are still controversial. Here, we focused on the 0.9 million km2 vegetation restoration region in China, where the highest significant vegetation cover changes on the earth. Multi-source remote sensing data were used to describe the characteristics of seasonality and transition of surface water and to analyse the causes of surface water changes from climate, vegetation cover and other human factors. Our results show that the annual maximum NDVI of Northeast region (NE) and Loess Plateau region (LP) increased significantly from 0.74 to 0.85 and 0.49 to 0.62 from 2000 to 2015, respectively. Meanwhile, permanent water, as a vital component of surface water, exhibited net increases of 695.6 km2 and 119.4 km2 in NE and LP from 2000 to 2015, respectively. The extension in permanent water and the implementation of ecological projects exhibited highly consistent spatiotemporal patterns. Statistical analysis indicated that vegetation cover is an important factor in controlling permanent water changes. Human activities such as building dams and reservoirs are also an important explanatory variable for permanent water increases. The newly built dams contributed 43% in NE and 25% in LP to the increase in permanent water. In addition, although climatic factors were not the main factor influencing permanent water, precipitation significantly affected the total surface water in NE. These findings have potential implications for understanding surface water and forest dynamics and formulating regional development plans in the vegetation restoration region in China.

Morfo-Physiological Response of Three Shallot Varieties on Water Surface Variation Level

The morpho-physiological response study of three shallots varieties on the water surface variation level of the trench aims to find plants that are tolerant of water shortages. The study was conducted in the rice fields of Pulosari village, Brebes District, Brebes Regency, Central Java, Indonesia for three months (January to March 2019). The experimental design used was a separate plot design with three replications. The main plot of trench water surface height (T) is T1 = 10 cm, T2 = 20 cm and T3 = 30 cm. The subplots of shallot variety (V) are V1 = Bima, V2 = Yellow and V3 = Sumenep. The data obtained were analyzed using analysis of variance at 5% error level, if there is a real difference found, the study would be followed by the Least Significant Difference Test (LSD) level 5%. The results showed that the condition of water shortage was very influential on the morpho-physiological response of three shallots varieties.

Spatial and temporal changes to a hydrologically-reconnected coastal wetland: Implications for restoration

Mississippi River Delta wetlands were isolated from river influence due to levee construction beginning in the early 1900's. Surface water diversions were primarily designed to manage salinity and maintain marsh vegetation by reintroducing Mississippi River water and nutrients into adjacent wetlands. Phosphorus (P) is a major limiting nutrient that can control productivity, but in excess can contribute to wetland eutrophic conditions and water quality degradation. Most wetland soil characterization assessments consider soil total P, however, this parameter alone cannot describe P bioavailability due to differences in organic and inorganic forms. A soil characterization of the Davis Pond diversion was done in 2007, before full-scale operation began, and in 2018 after 11 years of river loading. The top 10 cm of soil from 140 stations each year were analyzed for physiochemical properties and both organic and inorganic P forms. Mineral content is used to delineate areas of river diversion influence and compare P stocks between hydrologically isolated marsh areas and where effective river diversion reconnection took place. The river diversion resulted in a nearly 100% increase in soil mineral content and 58% increase in bulk density. The dominant source of soil P has changed from organic P to inorganic P in 29% of the wetland area, significantly associated with mineral content of the soil. Inorganic P stocks in diversion influenced areas are 9 times higher than those which remained isolated from riverine materials. The study demonstrates that long-term addition of mineral sediments and inorganic P did not lead to deleterious effects in the wetland soil. This is the first study in the Mississippi River delta to spatially track river reconnection driven wetland P dynamics and can provide valuable information for predictive models for sediment diversions for coastal restoration.

A systems approach to understand microplastic occurrence and variability in Dutch riverine surface waters

Assessment methods on data quality and environmental variability are lacking for microplastics (MP). Here we assess occurrence and variability of MP number concentrations in two Dutch rivers. Strict QA/QC procedures were applied to identify MP using Fourier-transform infrared (FTIR) microscopy followed by state of the art automated image analysis. For a series of randomly selected, yet ever smaller subareas of filters, we assessed how accurately MP numbers and polymer types are represented during partial filter analysis. Levels of uncertainty were acceptable when analysing 50% of a filter during chemical mapping, and when identifying at least a subset of 50 individual particles with attenuated total reflection (ATR)-FTIR. Applying these guidelines, MP number concentrations between 67 and 11532 MP m−3 were detected in Dutch riverine surface waters. Spatial differences caused MP number concentrations to vary by two orders of magnitude. Temporal differences were lower and induced a maximum variation of one order of magnitude. In total, 26 polymer types were identified, the most common were polyethylene (23%), polypropylene (19.7%) and ethylene propylene diene monomer rubber (18.3%). The highest diversity of polymer types was found for small MPs, whereas MP larger than 1 mm was scarce and almost exclusively made of polyethylene or polypropylene. Virtually all sampling locations revealed MP number concentrations that are considerably below known effect thresholds for anticipated adverse ecological effects.

Climate and Land-Use Controls on Surface Water Diversions in the Central Valley, California

California’s Central Valley (CV) is one of the most productive agricultural regions in the world, enabled by the conjunctive use of surface water and groundwater. We investigated variations in the CV’s managed surface water diversions relative to climate variability. Using a historical record (1979−2010) of diversions from 531 sites, we found diversions are largest in the wetter Sacramento basin to the north, but most variable in the drier Tulare basin to the south. A rotated empirical orthogonal function (REOF) analysis finds 72% of the variance of diversions is captured by the first three REOFs. The leading REOF (35% of variance) exhibited strong positive loadings in the Tulare basin, and the corresponding principal component time-series (RPC1) was strongly correlated (ρ > 0.9) with contemporaneous hydrologic variability. This pattern indicates larger than average diversions in the south, with neutral or slightly less than average diversions to the north during wet years, with the opposite true for dry years. The second and third REOFs (20% and 17% of variance, respectively), were strongest in the Sacramento basin and San Francisco Bay−Delta. RPC2 and RPC3 were associated with variations in agricultural- and municipal-bound diversions, respectively. RPC2 and RPC3 were also moderately correlated with 7-year cumulative precipitation based on lagged correlation analysis, indicating that diversions in the north and central portions of the CV respond to longer-term hydrologic variations. The results illustrate a dichotomy of regimes wherein diversions in the more arid Tulare are governed by year-to-year hydrologic variability, while those in wetter northern basins reflect land-use patterns and low-frequency hydrologic variations.

Variation of alpine lakes from 1986 to 2019 in the Headwater Area of the Yellow River, Tibetan Plateau using Google Earth Engine

To understand the variations in surface water associated with changes in air temperature, precipitation, and permafrost in the Headwater Area of the Yellow River (HAYR), we studied the dynamics of alpine lakes larger than 0.01 km2 during 1986–2019 using Google Earth Engine (GEE) platform. The surface areas of water bodies in the HAYR were processed using mass remote sensing images consisting of Landsat TM/ETM+/OLI, Sentinel-2A, and MODIS based on automatic extraction of water indices under GEE. Besides, the lake ice phenology of the Sister Lakes (the Gyaring Lake and the Ngöring Lake) was derived by threshold segmenting of water/ice area ratio. Results demonstrate that the change of surface areas experienced four stages: decreasing during 1986–2004, increasing during 2004–2012, decreasing again during 2012–2017, and increasing again during 2017–2019. Correspondingly, the number of small lakes decreased (−26.5 per year), increased (139.5 per year), again decreased (−109.0 per year), and again increased (433.0 per year). Eight lakes larger than 1 km2 disappeared in 2004 but restored afterward. The overall trends in the area of small lakes (0.01–1 km2), large lakes (>1 km2), and all lakes during 1986–2019 were 0.4, 3.1, and 3.4 km2 per year, respectively. Although the onsets of freezing, freeze-up, breaking and the break-up of the Sister Lakes varied from year to year, there is no obvious trend regarding the lake ice phenology. Tendencies of lake variations in the HAYR are primarily related to the increased net precipitation and the declined aridity, followed by the construction of hydropower station around the outlet of the Ngöring Lake, as well as permafrost degradation.

Improvement and Application Analysis of Lake Water Body Tracking and Recognition Algorithm

Basing on 30 years’ historical image data sources of Sanshan Lake between 1986 and 2017, this paper proposes a water body tracking and recognition algorithm according to the complex water area features of the lake and its branches to conduct the extraction of the historical water surface area and analysis on influence factors of Sanshan Lake. Comparing to conventional image extraction methods such as the region growing algorithm and the two-pass scanning method, this method shows its advantage of being fast and accurate. By analysing the water surface variation law of Sanshan Lake in 30 years and the influence factors, the area of Sanshan Lake is found to show a significant attenuation trend with the annual average attenuation rate reaches 0.98%; the water surface area weakly correlated with the precipitation change; the lake shore waterline line retreated 0.3- 10 meters in the 30 years; the pond and farmland area increased by 133%, indicating that the regulation of the lake water body is more affected by the lake shoreline dike and the Regulating capacity of gate pump.

Development and Application of a Microplate Assay for Toxicity Testing on Aquatic Cyanobacteria.

Regulatory environmental risk assessment, applied to establish a protection limit for all bacterial diversity in surface waters, relies on a growth inhibition test performed on a single species of cyanobacteria and the activated sludge respiration inhibition test. Recently, the ability of this approach to protect adequately for bacteria that provide important ecosystem services has been questioned, and empirical data on additional species to further investigate the effectiveness of the environmental risk assessment are urgently required. We present the development and validation of a cost-effective and time-efficient microplate assay that is comparable to the traditional shake flask test for measurement of cyanobacteria growth rate after chemical exposure. The assay has been optimized to ensure that comparisons of cyanobacteria sensitivity under exponential growth are assessed across equivalent experimental conditions using phycocyanin fluorescence as a surrogate for cell density. The test system is validated using potassium dichromate, and the results are compared with those obtained in an Organisation for Economic Co-operation and Development (2011) test guideline 201 shake flask test system. This assay is suitable for the screening of new and legacy chemicals (including antibiotics) for which ecotoxicology data are lacking across a wide range of cyanobacteria, with the aim of developing more comprehensive environmental risk assessment. Environ Toxicol Chem 2020;39:705-720. © 2019 SETAC.

Seasonal macrophyte growth constrains extent, but improves quality, of cold‐water habitat in a spring‐fed river

AbstractRooted aquatic macrophytes affect abiotic conditions in low‐gradient rivers by altering channel hydraulics, consuming biologically available nutrients, controlling sediment transport and deposition, and shading the water surface. Due to seasonal macrophyte growth and senescence, the magnitude of these effects may vary temporally. Seasonal changes in aquatic macrophyte biomass, channel roughness and flow velocity, were quantified and trends were related to spatiotemporal patterns in water temperature in a low‐gradient, spring‐fed river downstream from high‐volume, constant‐temperature groundwater springs. Between spring and summer, a nearly threefold increase in macrophyte biomass was positively correlated with channel roughness and inversely related to flow velocity. On average, flow velocity declined by 34% during the study period, and channel roughness increased 63% (from 0.064 to 0.104). During the spring and fall period, the location of a minimum water temperature variability “node” migrated upstream more than 4 km, whereas daily maximum water temperature cooled by 2–3°C. Water temperature modelling shows that the longitudinal extent of cold‐water habitat was shortened due to increased channel roughness independent of seasonal surface water diversions. These results suggest that macrophyte growth mediates spatiotemporal patterns of water temperature, constraining available cold‐water habitat while simultaneously improving its quality. Understanding complex spatial and temporal dynamics between macrophyte growth and water temperature is critical to developing regulatory standards reflective of naturally occurring variability and has important implications for the management and conservation of cold‐water biota.

Surface and deep water variability in the Western Mediterranean (ODP Site 975) during insolation cycle 74: High-resolution calcareous plankton and molecular biomarker signals

We reconstructed changes in productivity and surface/subsurface and deep-water dynamics in the Western Mediterranean through a multi-proxy study of Ocean Drilling Program Site 975 between late Marine Isotope Stage (MIS) 20 and early interglacial MIS 19. Our high-resolution study (down to ~200-year resolution) combines calcareous plankton assemblages (coccolithophores and foraminifera), biomarkers (C37-alkenones, n-alkanes, n-alcohols) and elemental proxies (total organic carbon, total nitrogen, calcium carbonate). Surface water conditions are derived (i) from high-resolution δ18O and δ13C records obtained from the planktonic foraminifer Globigerina bulloides, and (ii) from summer and winter, foraminifera-based sea surface temperature reconstructions (SSTJAS-foram, SSTJFM-foram) achieved through transfer function. The integration of the whole dataset makes it possible to identify in the Balearic Sea, and to accurately characterize for the first time, an Organic Rich Layer (ORL) during latest MIS 20-early MIS 19, close to i-cycle 74. Its presence is marked firstly by higher values of total nitrogen (TN) and an increase of total C37-alkenone and total organic carbon (TOC) preserved in the sediments. The multi-proxy approach reveals that the deglacial phase played a prominent role for ORL formation that was characterized by centennial scale phases. The alcohol preservation index (API) suggests that the shoaling of the circulation, which boosted marine productivity, started in the deglaciation and, in combination with freshening by Atlantic water inflow/riverine input and surface water buoyancy during sea level rising, culminated during the ORL event. At this time calcareous plankton proliferated on subsurface-surface waters, benefiting from ameliorating conditions, which promoted maximum marine productivity and higher organic matter preservation on the seafloor.

黄土区小流域植被类型对沟坡地土壤水分循环的影响

PDF HTML阅读 XML下载 导出引用 引用提醒 黄土区小流域植被类型对沟坡地土壤水分循环的影响 DOI: 10.5846/stxb201902120248 作者: 作者单位: 作者简介: 通讯作者: 中图分类号: 基金项目: 基金面上项目（41771311）；国家自然科学基金国际（地区）合作与交流项目（41561144011）；国家自然科学基金（41807066） Effects of vegetation types in small watershed on soil water cycle in gully-slope land of loess region Author: Affiliation: Fund Project: 摘要 | 图/表 | 访问统计 | 参考文献 | 相似文献 | 引证文献 | 资源附件 | 文章评论 摘要:沟坡作为黄土丘陵区小流域水土流失最为活跃的区域，探究不同下垫面植被类型下的土壤水分循环特征对于沟坡地植被恢复具有重要意义。基于氢氧同位素示踪技术，通过野外水样采集和室内同位素分析旨在揭示植被类型对沟坡地土壤水分循环的影响机制。结果表明：（1）各水体氢氧同位素均遵循：降水 > 刺槐林地土壤水 > 草地土壤水 > 地表水 > 地下水，降水的变异系数最大，地表水和地下水的变异系数较小。（2）草地土壤水主要以降水补给为主，所占比例为59.12%，刺槐林地土壤水则以深层土壤水的上升补给为主，所占比例为60.97%。短阵性暴雨条件下，草地土壤水运移速率较刺槐林地高约1 cm/d，且主要发生在0-50 cm土层。（3）土壤水的垂向运移为地下水的主要补给形式，草地土壤水对地下水的补给比例为51.64%，约比刺槐林地高0.52%。表明植被类型对土壤水分循环特征具有一定的影响，刺槐林对深层土壤水分利用强度较大，可能加剧深层土壤干层化，而草地更有利于降水入渗以及地下水补给，该研究可为小流域沟坡的生态修复和综合治理提供科学依据。 Abstract:The gully-slope land is the most active area of soil erosion in small watershed of loess hilly region. It is of great significance to explore the characteristics of soil water cycle under different underlying vegetation types for vegetation restoration on gully-slope land. Based on the hydrogen and oxygen isotope tracer technique, the mechanism of vegetation types affecting soil water cycle in gully-slope land was revealed through field water sample collection and indoor isotope analysis. The results were: (1) The hydrogen and oxygen isotope concentration in the five water bodies decreased in an orderly way, with precipitation being observed to have the greatest amount, followed by soil water of black locust forest, then soil water of grassland, then surface water, finally groundwater. The coefficient of variation of precipitation was the largest, and the coefficient of variation of surface water and groundwater was smaller. (2) Soil water in grassland was mainly recharged by precipitation, accounting for 59.12%. Soil water in black locust forest was mainly recharged by the rising of deep soil water, accounting for 60.97%. Under the condition of short-burst rainstorm, the water transport rate of grassland soil was about 1 cm/d higher than that of black locust forest. And the main transport ranges of soil water in two vegetation types were 0-50 cm. (3) The vertical migration of soil water was the main form of groundwater recharge. The groundwater recharge ratio by soil water of grassland was 51.64%, which was about 0.52% higher than that of black locust forest. It indicated that the vegetation type had certain influence on the characteristic of soil water cycle. Black locust forest had a strong utilization of deep soil water, which might aggravate the dried soil layer of deep soil. And the grassland was more conducive to precipitation infiltration and groundwater recharge. This study can provide a scientific basis for ecological restoration and comprehensive management of gully-slope land in small watershed. 参考文献 相似文献 引证文献

Adaptive capacity in the foundation tree species Populus fremontii: implications for resilience to climate change and non-native species invasion in the American Southwest.

Populus fremontii (Fremont cottonwood) is recognized as one of the most important foundation tree species in the southwestern USA and northern Mexico because of its ability to structure communities across multiple trophic levels, drive ecosystem processes and influence biodiversity via genetic-based functional trait variation. However, the areal extent of P. fremontii cover has declined dramatically over the last century due to the effects of surface water diversions, non-native species invasions and more recently climate change. Consequently, P. fremontii gallery forests are considered amongst the most threatened forest types in North America. In this paper, we unify four conceptual areas of genes to ecosystems research related to P. fremontii’s capacity to survive or even thrive under current and future environmental conditions: (i) hydraulic function related to canopy thermal regulation during heat waves; (ii) mycorrhizal mutualists in relation to resiliency to climate change and invasion by the non-native tree/shrub, Tamarix; (iii) phenotypic plasticity as a mechanism for coping with rapid changes in climate; and (iv) hybridization between P. fremontii and other closely related Populus species where enhanced vigour of hybrids may preserve the foundational capacity of Populus in the face of environmental change. We also discuss opportunities to scale these conceptual areas from genes to the ecosystem level via remote sensing. We anticipate that the exploration of these conceptual areas of research will facilitate solutions to climate change with a foundation species that is recognized as being critically important for biodiversity conservation and could serve as a model for adaptive management of arid regions in the southwestern USA and around the world.

Decadal‐Scale Aquifer Dynamics and Structural Complexities at a Municipal Wellfield Revealed by 25 Years of InSAR and Recent Groundwater Temperature Observations

AbstractOver the past 35 years the Buckman wellfield near Santa Fe, New Mexico, experienced production well drawdowns in excess of 180 m, resulting in ground subsidence and surface cracks. Increased reliance on surface water diversions since 2011 has reduced pumping and yielded water level recovery. To characterize the impact of wellfield management decisions on the aquifer system, we reconstruct the surface deformation history through the European Remote Sensing Satellite, Advanced Land Observing Satellite, and Sentinel‐1 Interferometric Synthetic Aperture Radar (InSAR) time series analysis during episodes of drawdown (1993–2000), recovery (2007–2010), and modern management (2015–2018) in discontinuous observations over a 25‐year period. The observed deformation generally reflects changes in hydraulic head. However, at times during the wellfield recovery, the deformation signal is complex, with patterns of uplift and subsidence suggesting a compartmentalized aquifer system. Recent records of locally high geothermal gradients and an overall warming of the system (~0.5°C during the water level recovery) obtained from repeat temperature measurements between 2013 and 2018 constrain a conceptual model of convective heat transfer that requires a vertical permeable zone near an observed fault. To reproduce observed temperature patterns at monitoring wells, high basal heat flow and convective cooling associated with downward flow of water from cool shallow aquifers during the drawdown period is necessary. The fault, however, appears to die out southward or may be locally permeable, as conceptual cross‐sectional hydrologic modeling reproduces the surface deformation without such a structure. Our work demonstrates the importance of incorporating well‐constrained stratigraphy and structure when modeling near‐surface deformation induced by, for instance, groundwater production.

Divergent sensitivity of surface water and energy variables to precipitation product uncertainty in the Tibetan Plateau

Precipitation is a major driving factor for land surface water and energy balances. Uncertainty in global precipitation products over observation sparse regions such as the Tibetan Plateau (TP) is generally large. Sensitivity of surface water and energy variables to precipitation uncertainty can provide clues for confidence that can be assigned to simulated water and energy variables in such regions. In this study, the sensitivities of surface water and energy variables to global precipitation product uncertainty over four large river basins in the TP are quantified and inter-compared based on a newly developed sensitivity analysis approach. A water and energy budget-based distributed hydrological model including biosphere is utilized after calibration and validation against observed runoff and Land Surface Temperatures (LSTs) from Moderate Resolution Imaging Spectroradiometer (MODIS). Eight global precipitation products are used to represent the precipitation uncertainty. Results show that Canopy interception loss (CIE) and runoff are highly sensitive to the uncertainty in general, whereas LSTs are not sensitive. Therefore, confidence in simulated CIE and runoff can be considered relatively low when using global precipitation products in the four basins. These results imply that other simulated variables may have large uncertainty even when LSTs simulation performs well, and accurate simulations of CIE and runoff require high accuracy in precipitation. Because CIE has profound influence on local hydrological cycle, the results also imply that utilizing the most accurate precipitation product is critical for local scale hydrological cycle research.

Understanding the hydrometeorological characteristics and relationships in the semiarid region of Maharashtra (western India): implications for water management

In spite of enormous investment for water harvesting in Maharashtra, the issue of water deficiency persist. Therefore, with the proper understanding of recent (1975–2014) hydrometeorological characteristics in the semiarid region of Maharashtra, the study endeavored to suggest management strategies to optimize the water resources. To understand the inherent characteristics of rainfall, runoff, dam storages and groundwater, statistical techniques including descriptive statistics, correlation, regression and Student’s t test were applied. The monsoon rainfall has notable control over the water resources. As the study region characterized by significantly low water availability with high variability which is accountable for higher frequency and intensity of drought, it should be prioritized while formulating a judicial plan for water management. The major rivers of Maharashtra follow the unimodal pattern of rainfall. Whereas the study area displays a peculiar character of the bimodal and unimodal regimes of rainfall and runoff, respectively, this highlights the role of hydrological losses. However, it also indicates that there is a wide scope to harvest surface water, particularly during the months of September and October. Interestingly, the inter-annual variability in the extreme rainfall and runoff events over the study basins is observed to be higher in India. Most of the water (> 50%) received during flashy rainfall events drains out through flashy discharges. The impoundment of this water and modified irrigation schedule by considering the recent hydrological characteristics may diminish the variability and deficiency of surface and subsurface water. Furthermore, for the precise forecast of water availability in the study area, ENSO condition needs to incorporate, as it has a significant connection with rainfall and runoff.