Multi-year Storage Research Articles

Operational strategies and well design for reservoir thermal energy storage (RTES)

The intermittency of renewable energy sources necessitates effective energy storage solutions. This study narrows in on reservoir thermal energy storage (RTES) as a system to bridge the supply–demand gap through the storage and recovery of heated water for periods ranging from daily to monthly timescales. By injecting hot water into subsurface formations and later retrieving it for use in electricity generation or direct heating, the viability of RTES is explored for load-levelling applications, typically on daily to monthly timescales rather than extended seasonal or multi-year storage. Many factors including formation parameters (e.g. permeability, porosity, thermal conductivity of rock, thickness and insulating layers), completion parameters such as injection well design, operational parameters such as injection and production rates, and schedule affect the facility's performance. The two key performance indicators (KPI) considered herein are the produced water temperature and the heat recovery factor. In this study, three operational strategies and four different well completions were investigated using a coupled fluid–thermal simulation model. Heat loss from the upper and lower boundaries of the reservoir was also studied. While the immediate impact of initial hydro-thermal charging on produced water temperature may not persist in the long-term operation, it does influence the overall system efficiency by reducing the cumulative heat recovery. Through detailed analysis, it is demonstrated that vertical injection across the entire well length offers a balanced approach between minimizing pumping costs and maximizing heat extraction efficiency. This study establishes basic calculations for developing innovative operational and completion strategies to maximize the long-term economic benefit of RTES.

Evaluating Seed Enhancement Technology's Effects on Seed Viability during Multi-Year Storage: A Case Study Using Herbicide Protection Pellets.

The viability of seed often decreases during multi-year storage. For seed enhancement technologies (SETs) that apply treatments to native seed prior to sowing in restoration projects, it is important to determine if SETs affect the rate of viability loss in storage to understand if treated seeds can tolerate storage or if they must be sown immediately after treatment. Examining herbicide protection pellet (HPP) seed technology, we conducted germination trials on 10 seedlots of four species to compare three treatments: original bare seed kept in seed storage for 2-3 years, seed retrieved from 2-3-year-old HPPs made from pre-storage original bare seed (old HPPs), and seed retrieved from HPPs that were freshly-made using post-storage original bare seed (new HPPs). For three perennial bunchgrasses, we saw equal or higher germinability of seed from old HPPs compared to the original bare seed and new HPPs, suggesting application of HPP technology to these species prior to multi-year storage is suitable. For the seeds of a perennial shrub, although we saw greater germination of original bare seeds compared to old HPPs, the lowest germination was from new HPPs, still suggesting HPP application prior to storage as a suitable practice. We suggest these tests be performed with all new SETs under development for ecological restoration.

Partitioning of Precipitation Into Terrestrial Water Balance Components Under a Drying Climate

AbstractTo accurately project future water availability under a drying climate, it is important to understand how precipitation is partitioned into other terrestrial water balance components, such as fluxes (evaporation, transpiration, runoff) and changes in storage (soil moisture, groundwater). Many studies have reported unexpected large runoff reductions during drought, particularly for multi‐year events, and some studies report a persistent change in partitioning even after the meteorological drought has ended. This study focused on understanding how actual evapotranspiration (AET) and change in subsurface storage (ΔS) respond to climate variability and change, examining Australia's Millennium Drought (MD, 1997–2009). The study initially conducted a catchment‐scale water balance analysis to investigate interactions between ΔS and AET. Then the water balance analysis was extended to regional scale to investigate ΔS using interpolated rainfall and discharge with remotely sensed AET. Lastly, we evaluated conceptual rainfall‐runoff model performance of two commonly used models against these water balance estimates. The evaluation of water‐balance‐derived ΔS against Gravity Recovery and Climate Experiment (GRACE) estimates shows a significant multiyear storage decline; however, with different rates. In contrast, AET rates (annualized) remained approximately constant before and during the MD, contrasting with some reports of evapotranspiration enhancement elsewhere. Overall, given AET remained approximately constant, drought‐induced precipitation reductions were partitioned into ΔS and streamflow. The employed conceptual rainfall‐runoff models failed to realistically represent AET during the MD, suggesting the need for improved conceptualization of processes. This study provides useful implications for explaining future hydrological changes if similar AET behavior is observed under a drying climate.

P-449 Storage of vitrified oocytes up to 8 years does not affect pregnancy and live birth rates: analysis of 5,362 cycles

Abstract Study question Does long-term storage of vitrified oocytes affect laboratory and reproductive outcomes after ICSI? Summary answer The time spent by vitrified oocytes in liquid nitrogen banks does not affect oocyte survival, fertilization rate nor reproductive outcomes up to live birth. What is known already Vitrification is the most efficient approach to oocyte cryopreservation and is commonly applied in oocyte donation programs. The survival rate can be >90% and vitrified-warmed oocytes provide comparable reproductive results to fresh oocytes. However, even with modern cryobanking technology, there are potential temperature fluctuations caused by access to cryopreserved material, transportation, stocktaking events, and regular maintenance. While some studies indicate that a multiyear storage of vitrified oocytes does not affect pregnancy rates, others found decreased reproductive outcomes after as little as 6 months, and further investigations in large cohorts are needed to confirm the safety of long-term oocyte storage. Study design, size, duration Retrospective cohort study of 5,362 cycles with vitrified oocytes from oocyte donors carried out between 2013 and 2021. All cycles included fresh embryo transfer (ET). Oocyte vitrification and warming were carried using the Cryotop® protocol (Kitazato). We analyzed the effect of storage time of vitrified oocytes in liquid nitrogen vapors on laboratory outcomes (oocyte survival, fertilization rate (FR), percentage of viable embryos) and reproductive outcomes (pregnancy -biochemical and clinical- and live birth (LB) rates). Participants/materials, setting, methods Eight categories of storage time were established: 0-0.25 years (reference group, ≤3 months), 0.25-0.5, 0.5-1, 1-1.5, 1.5-2, 2-3, 3-4, and >4 years. The effect of oocyte storage time on laboratory and reproductive outcomes was analyzed by linear and logistic regression, respectively. These multivariate analyses were adjusted by multiple factors: sperm origin (partner vs donor), sperm parameters, number of oocytes inseminated, number of embryos transferred and day of ET (2-3 vs 5), among others. Main results and the role of chance Mean recipient age was 42.0±4.6, while oocyte donors age was 26.1±4.6. The mean number of thawed oocytes was 8.0±2.5, all surviving oocytes were inseminated by ICSI with partner (84.9%) or donor sperm (15.1%). The oocyte storage time ranged from 3 days to 8.2 years (mean: 0.7 ± 0.9 years). We did not find significant differences in oocyte storage time between positive and negative pregnancy and LB, nor between different survival rates (<100 vs = 100%), FR (<70 vs ≥ 70%) and percentages of viable embryos (<50 vs ≥ 50%) at univariate analysis (p > 0.05 in all cases). The mean oocyte survival rate was 90.2%±14.7% and, after adjusting for confounders, did not decrease with longer storage time (i.e. 88.9% for time >4 years, p = 0.963). Similarly, the linear regression model did not show a significant effect of storage time on FR, which was close to 70% in all categories (range: 67.6-70.6, p > 0.05), nor a decrease in the percentage of viable embryos. Finally, reproductive outcomes were similar across storage times (p > 0.05 for all categories when compared to the reference 0-0.25); specifically, long-term oocyte storage (>4 years) did not affect the chances of clinical pregnancy (OR: 0.657 [0.395-1.092], p = 0.194) and LB (OR: 0.666 [0.393-1.128], p = 0.231). Limitations, reasons for caution These results cannot be extended to cycles using the patient’s own oocytes or involving a severe male factor (testicular spermatozoa or criptozoospermia), which were excluded. Due to the retrospective nature of the study, some uncontrolled variables could affect the results. Wider implications of the findings This is the first study evaluating the effect of long-term oocyte storage on a large cohort of patients undergoing oocyte donation, thus partially discarding the effect of the female factor. Reassuringly, these results indicate that long-term storage of oocytes is a safe option for young patients and oocyte banks. Trial registration number Not applicable

Evaluating a reservoir parametrization in the vector-based global routing model mizuRoute (v2.0.1) for Earth system model coupling

Abstract. Human-controlled reservoirs have a large influence on the global water cycle. While global hydrological models use generic parameterizations to model dam operations, the representation of reservoir regulation is still lacking in many Earth system models. Here we implement and evaluate a widely used reservoir parametrization in the global river-routing model mizuRoute, which operates on a vector-based river network resolving individual lakes and reservoirs and is currently being coupled to an Earth system model. We develop an approach to determine the downstream area over which to aggregate irrigation water demand per reservoir. The implementation of managed reservoirs is evaluated by comparing them to simulations ignoring inland waters and simulations with reservoirs represented as natural lakes using (i) local simulations for 26 individual reservoirs driven by observed inflows and (ii) global-domain simulations driven by runoff from the Community Land Model. The local simulations show the clear added value of the reservoir parametrization, especially for simulating storage for large reservoirs with a multi-year storage capacity. In the global-domain application, the implementation of reservoirs shows an improvement in outflow and storage compared to the no-reservoir simulation, but a similar performance is found compared to the natural lake parametrization. The limited impact of reservoirs on skill statistics could be attributed to biases in simulated river discharge, mainly originating from biases in simulated runoff from the Community Land Model. Finally, the comparison of modelled monthly streamflow indices against observations highlights that including dam operations improves the streamflow simulation compared to ignoring lakes and reservoirs. This study overall underlines the need to further develop and test runoff simulations and water management parameterizations in order to improve the representation of anthropogenic interference of the terrestrial water cycle in Earth system models.

Long-duration energy storage for reliable renewable electricity: The realistic possibilities

ABSTRACT Several American states mandate zero-carbon electricity systems based primarily on renewable technologies such as wind and solar power. Reliable and affordable electricity systems based on these variable resources may depend on the ability to store large quantities of low-cost energy over long timescales. Long-duration storage technologies (that is, those that provide from 10 to hundreds of hours of storage) have much cheaper energy storage capital costs than lithium-ion batteries. Long-duration storage plays unique roles, such as seasonal and multi-year storage, that increase the affordability of electricity from variable renewable energy. We compare realistic options for seasonal energy storage, including underground hydrogen, pumped hydro, pumped thermal, and compressed air systems. To make 100 percent renewable electricity reliable and more affordable, such long-duration storage technologies can be employed.

Hummock-scale controls on groundwater recharge rates and the potential for developing local groundwater flow systems in water-limited environments

We use two-dimensional numerical models to identify controls on groundwater recharge, water table dynamics, and the sink-source function of fine-textured hummocks in water-limited environments. A silty clay loam hummock with aspen forest cover in the sub-humid Boreal Plains region of Canada is used to develop a conceptual model and calibrate a variably-saturated flow model to better investigate the dynamics of recharge, water table position, and lateral flow between the forested hummock and adjacent peatland. Scenario testing (achieved by raising and lowering the hydraulic conductivity by an order of magnitude and altering the hummock height and length) provides further understanding of the controls that hydraulic conductivity and hummock morphometry exert on recharge and forestland-peatland interactions. We find that the hydraulic conductivity of the glacial till has the largest control over recharge, followed by the hummock height and length and, lastly, annual atmospheric fluxes. Hummocks with higher hydraulic conductivity or long morphometric profiles are most often sinks of water as they promote increased root-water uptake, while taller hummocks with lower hydraulic conductivity tend to act as hydrologic sources for adjacent wetlands. The magnitude of annual recharge and water table elevation are poorly correlated with annual atmospheric fluxes due to the strong effects of multi-year storage deficits or surpluses; however, they are appreciably affected by decadal wet-dry cycles typical of the Boreal Plains climate. Additionally, we show that both distance along a hummock and elevation are key factors in controlling the spatial distribution of recharge at a single hummock. It is common to conceptualize the water table as a shallow and subdued replica of surface topography, where water flows from topographic highs (i.e., forestlands) to topographic lows (i.e., peatlands) in humid environments; however, as we show here, recharge rates, water table elevation, and the sink-source function of a forested hummock in water-limited environments is highly variable in time and space, and strongly dependent on both the hydrogeological and morphometric properties of the hummock.

Techno-economic analysis of long-duration energy storage and flexible power generation technologies to support high-variable renewable energy grids

Techno-economic analysis of long-duration energy storage and flexible power generation technologies to support high-variable renewable energy grids

Hydrological Tracking Model for Amazon Surface Waters

AbstractThis study presents an alternative model for hydrological tracking of surface waters designed to investigate multiyear storage and movement of water in large river basins. We coupled this model with a background solution from a large‐scale hydrological‐hydrodynamic model to study the fate of waters in the Amazon River basin (6 million km2) considering the following: (i) the surface water travel times, (ii) the role of large floodable areas (17% of the basin), and (iii) the relations between water composition and lithological sources. Through numerical experiments, we investigated the spatial distribution of in‐stream surface water travel time for the Amazon River Basin (relative to the outlet) and the role of floodplains in seasonal water storage. We estimate that surface water travel time is likely to be less than 90 days (median of 45 days), although about 20% of the flowing water passes through large floodplains. Our modeling exercises indicate that whole‐basin monthly water net balance between river and floodplain can reach up to magnitudes of 105 m3/s; the water exchanged with floodplains during the annual floods can represent a large portion (up to 40%) of the basin discharge during low waters season. Finally, we took advantage of the tracking approach to study the hydrograph composition based on parent river lithology quantifying the role of major tributaries. Parallel to the development of global hydrology databases, new modeling approaches are also required to push advances in the discussion of renewal and travel times of surface waters in large river basins.

Role of Long-Duration Energy Storage in Variable Renewable Electricity Systems

Summary Reliable and affordable electricity systems based on variable energy sources, such as wind and solar may depend on the ability to store large quantities of low-cost energy over long timescales. Here, we use 39 years of hourly U.S. weather data, and a macro-scale energy model to evaluate capacities and dispatch in least cost, 100% reliable electricity systems with wind and solar generation supported by long-duration storage (LDS; 10 h or greater) and battery storage. We find that the introduction of LDS lowers total system costs relative to wind-solar-battery systems, and that system costs are twice as sensitive to reductions in LDS costs as to reductions in battery costs. In least-cost systems, batteries are used primarily for intra-day storage and LDS is used primarily for inter-season and multi-year storage. Moreover, dependence on LDS increases when the system is optimized over more years. LDS technologies could improve the affordability of renewable electricity.

Revealing the water-energy-food nexus in the Upper Yellow River Basin through multi-objective optimization for reservoir system

Since the 21st century, the natural runoff from the headwater region of the Yellow River has generally been decreasing, resulting in a particularly prominent contradiction in utilization of water resources. In this study, key components were identified from the perspective of water-energy-food (WEF) nexus, and a WEF nexus model was established for the Upper Yellow River Basin (UYRB), taking into consideration the benefits of water supply to the middle and lower reaches of Yellow River, food growth in major food-producing areas in the UYRB and hydropower utilization of the UYR reservoir system. The Multi-start Solver of LINGO and the ε constraint method were used to carry out multi-objective optimization, revealing the trade-off between the WEF benefits. 1) The model computed the Pareto non-inferior set of solutions for the electricity generated by the UYR reservoir system and the degree to which the water demands of the main intake areas (Ningxia and Inner Mongolia irrigated areas, and Toudaoguai section) are satisfied, quantifying the improvement room for the overall benefits brought about by the jointly optimal operation of the WEF sectors. 2) The historical operation of Longyangxia Reservoir, a multi-year storage reservoir, was evaluated, the results of which show that the realization of the WEF benefits is determined by the proper operation of Longyangxia Reservoir. To guarantee the overall benefits in the long term, Longyangxia Reservoir should maintain a high water level. 3) The trade-offs between the WEF benefits under different boundary conditions were discussed, including various initial/final fore-bay water levels of Longyangxia Reservoir and inflows of various total water amounts from the headwater region of the UYRB. The research reveals the WEF nexus in the UYRB under different scenarios, and moreover, the formulated multi-objective optimization model is a good example that can be extended to other similar WEF nexus systems worldwide.

Analysis and modeling of timber storage accumulation after severe storm events in Germany

In this study, we explore the determinants of forest enterprises’ timber storage accumulation after severe storm events. The explanatory power of variables reflecting economic, institutional and tree species-related factors is tested via econometric analyses. Timber storage accumulation is assessed conducting a weighted multiple linear regression analysis. In addition, the moderating effect of timber price alterations on timber storage accumulation is tested employing timber price alterations as a moderator variable in a hierarchical regression analysis. The results show a linear positive relation between forest enterprises’ damaged and stored timber quantities. It was found that coniferous timber was stored to a greater extent than non-coniferous timber which can be explained by higher storm damage as well as better suitability for multiyear storage. State forestry stored the highest shares of damaged timber, followed by municipal and private forest enterprises, which can be explained as a countervailing measure. A further central finding of our study is that the timber price drops after storm events act as a moderator variable on the relation between damaged and stored timber quantities. Hence, empirical timber price reactions help to improve estimation accuracy regarding the shares of damaged timber which are stored. Derived from our results, we find timber storage accumulation to be a common practice by forest companies to mitigate revenue losses caused by extreme storm events. As coefficients vary strongly among the analyzed variables’ categories, we consider case-specific storage accumulation estimations to be crucial for improving the accuracy of national wood and timber accounting, but also for a full view on storm-related economic damage in the forest sector. In addition, it is likely that capturing the proportions of timber storage in forests will gain relevance in the future, since forest damage from natural disturbances is expected to increase as a consequence of climate change.

Enhancing drought resilience with conjunctive use and managed aquifer recharge in California and Arizona

Projected longer-term droughts and intense floods underscore the need to store more water to manage climate extremes. Here we show how depleted aquifers have been used to store water by substituting surface water use for groundwater pumpage (conjunctive use, CU) or recharging groundwater with surface water (managed aquifer recharge, MAR). Unique multi-decadal monitoring from thousands of wells and regional modeling datasets for the California Central Valley and central Arizona were used to assess CU and MAR. In addition to natural reservoir capacity related to deep water tables, historical groundwater depletion further expanded aquifer storage by ∼44 km3 in the Central Valley and by ∼100 km3 in Arizona, similar to or exceeding current surface reservoir capacity by up to three times. Local river water and imported surface water, transported through 100s of km of canals, is substituted for groundwater (≤15 km3 yr−1, CU) or is used to recharge groundwater (MAR, ≤1.5 km3 yr−1) during wet years shifting to mostly groundwater pumpage during droughts. In the Central Valley, CU and MAR locally reversed historically declining water-level trends, which contrasts with simulated net regional groundwater depletion. In Arizona, CU and MAR also reversed historically declining groundwater level trends in active management areas. These rising trends contrast with current declining trends in irrigated areas that lack access to surface water to support CU or MAR. Use of depleted aquifers as reservoirs could expand with winter flood irrigation or capturing flood discharges to the Pacific (0–1.6 km3 yr−1, 2000–2014) with additional infrastructure in California. Because flexibility and expanded portfolio options translate to resilience, CU and MAR enhance drought resilience through multi-year storage, complementing shorter term surface reservoir storage, and facilitating water markets.

Performance and storage integrity of dried blood spots for PCB, BFR and pesticide measurements

Dried blood spots (DBSs) can provide accurate and valuable estimates of exposure to environmental toxicants, and the use of information derived from archived newborn DBSs has enormous potential to open up new research on the impacts of early chemical exposure on disease. Broad application of DBS for the purpose of quantitative exposure estimation requires robust and validated methods. This study investigates the suitability of DBS analyses for population studies of exposure to three chemical groups: polychlorinated biphenyls (PCBs), brominated flame retardants (BFRs), and chlorinated pesticides. It examines background (matrix) contamination, recovery and extraction variability, sensitivity, and storage stability. DBS samples prepared using 50μL of adult blood were analyzed by GC/MS, and method performance was confirmed by using certified materials and paired DBS-blood samples from six volunteers. Several of the target compounds and their degradation products have not been previously measured in DBSs. All target compounds were detected in DBS samples collected from the volunteers. Sample DBS cards showed background contamination of several compounds. When stored at room temperature, target compounds, excluding PBDEs, were stable for up to one month. When refrigerated or frozen, stability was acceptable for all compounds up to one year, and multiyear storage appears acceptable at colder (e.g., −80°C) temperatures. Multicompartment models may be used to estimate or correct for storage losses. Considering concentrations of contaminants for adults and children reported in the literature, and experimental values of detection limits and background contamination, DBS samples are suitable for quantifying exposures to many PCBs, BFRs and persistent pesticides.

Internal lipids of sugarbeet root maggot (Tetanops myopaeformis) larvae: Effects of multi-year cold storage

Sugarbeet root maggots, Tetanops myopaeformis (Diptera, Ulidiidae), survive more than five years of laboratory cold (6 degrees C) storage as mature third-instar larvae. To quantify energy costs associated with prolonged storage, internal lipids of larvae stored for 1, 2, 3, and 5 years were compared and characterized with those of field-collected diapausing larvae. Internal lipid concentration was highest (21.8% wet wt. and 29.8% dry wt.) in diapausing larvae. Lipids decreased progressively over storage time with greater than 70% reductions for 5-year stored larvae. Thin-layer chromatographic analysis revealed that triacylglycerols (TAGs) were the most predominant class of internal lipids, with trace amounts of diacylglycerols and hydrocarbons also being present. Gas chromatography-mass spectrometry (GC-MS) analyses of TAG fractions identified ten major fatty acids (FAs). The proportion of unsaturated FAs was higher (73 to 78%) than saturated FAs in diapausing and stored larval groups. Palmitoleic acid (16:1) was the predominant FA, constituting 40-50% of total unsaturated FAs with lesser amounts of myristoleic (14:1), oleic (18:1), lauroleic (12:1), gadoleic (20:1), and the saturated FAs, palmitic (16:0), myristic (14:0), lauric (12:0), stearic (18:0), and arachidic (20:0) being detected at much lower concentrations. Characterization of intact TAGs by high performance liquid chromatography and GC-MS revealed the presence of more than 40 TAG constituents. In conclusion, TAGs are utilized as an important energy source for T. myopaeformis larvae during diapause and long-term cold storage with no observed impact of multi-year storage on the TAG composition and distribution of their fatty acids.

On the probability of droughts: The compound renewal model

Droughts influence the planning and design of water supply infrastructure. Hydrologists ascertain drought duration, severity, and pattern of recurrence from instrumental and reconstructed records (e.g., using tree rings) of streamflow and precipitation. This work introduces a compound renewal model for the probabilistic analysis of multiyear drought recurrence. The compound renewal process generalizes the Poisson process. In the former the interarrival time between two consecutive events is the duration of nondrought conditions, and the events (i.e., droughts) have a probabilistic duration of at least θ years. The sum of the interarrival time and its subsequent drought duration is called the renewal time, which regenerates over time according to probabilistic laws derived in this work. Drought severity is incorporated in the analysis by means of a threshold quantile (e.g., the median or the average), so that low‐streamflow conditions become a drought whenever they last over θ years. A case study dealing with a river basin that has multiyear storage capacity, and in which droughts recurred frequently in the twentieth century, demonstrates the analytical power of the compound renewal model.

Role of ground water on hexachlorocyclohexane (lindane) detections in surface water in western Canada

AbstractInterrelationships between surface water and groundwater dynamics of α‐ and γ‐hexachlorocyclohexane (HCH) were investigated by determining their detection frequency and concentrations in surface water that originated primarily from surface runoff of snow and rain and in surface water that originated from ground water. In the prairie ecozone in Saskatchewan, where lindane (γ‐HCH) is currently used, lindane and α‐HCH were detected in about 50% of water samples taken from lakes and ponds that are recharged primarily by surface runoff (N = 43 sites). Maximum concentrations for lindane and α‐HCH were 0.011 and 0.004 μg/L, respectively. Isomers of HCH were not detected in any of the eight prairie springs that were examined (N = 10 samples). These springs originate from ground water located beneath agricultural lands. In the montane ecozone of Alberta where lindane is not used for agricultural purposes, only α‐HCH was detected frequently in the Waterton and Athabasca rivers. From 1976 to 1992, α‐HCH was detected in 81% of water samples from the Waterton River with no significant difference in detection frequency through the year (χ2 for 12 months = 14.6, d.f. = 11, p = 0.20, N = 163 samples). The site on the Waterton River is located downstream from a series of large lakes with multiyear storage of surface water. In contrast, discharge for the Athabasca River originates primarily from surface water during summer and ground water during winter. Detection frequency for α‐HCH during these seasons was 53% and 2%, respectively, with the annual pattern a normal distribution. These results indicate that HCH isomers were not detected frequently in surface waters that originate from ground water.

Atmospheric Water Vapor Transport in NCEP-NCAR Reanalyses: Comparison with River Discharge in the Central United States

The authors extract the water transport produced by the National Centers for Environmental Prediction reanalysis for a 10-yr period, 1984–93, and compare its convergence into two river basins with an independent dataset, river discharge (streamflow). Analysis focuses on two basins in the United States, the Upper Mississippi and the Ohio–Tennessee Basins, where the relatively high density of routine upper-air observations might be expected to give the reanalysis its closest rendition of the actual water transport. Over periods of several years, water input by the atmosphere should match water output from these basins in streamflow. However, in both basins an imbalance between the two with biases with respect to streamflow approaching 40% is found. The accuracy attributed to river discharge measurements averaged over several years and the apparent lack of significant multiyear storage in the basins lead us to conclude that the bias is largely an inaccuracy in the atmospheric transport. Temporal variability of atmospheric input and streamflow output shows somewhat better correspondence, with statistically significant correlations occurring for both basins on interannual and several-day timescales. The overall behavior suggests that the temporal variability of water transport depicted by the reanalysis can be used to gain insight into the actual variability of atmospheric transport, at least for well-observed regions such as the United States.