Water Management Operations Research Articles

Integrated water operations under climate change: Uluova Micro Basin example

ABSTRACT This study examines the impact of climate change on the Uluova Micro Basin, Turkey, employing an optimization model named ULUHEM across various water management and climate scenarios. With ULUHEM, the effects of different climate impact scenarios on agricultural water allocations, pumping costs, water scarcity, and scarcity costs were analyzed. The primary objective of this study is to identify gaps in demand within the current water supply infrastructure due to global warming and to develop adaptation strategies for basinwide water management operations. The research also emphasizes the importance of creating a basin-based hydroeconomic model that includes other surface water resources with a sustainable management approach to address the impact of climate change. In summary, the impacts of climate change on surface waters and groundwater in the Uluova Micro Basin include changes in water availability, water scarcity, and associated costs, and these have implications for agricultural water allocations and overall water management in the region. The study found that drier climate periods lead to reduced surface and groundwater input to farmland, resulting in increased water scarcity and scarcity costs. Conversely, periods characterized by wetter climates yield contrasting outcomes, alleviating water scarcity and its corresponding costs.

Using an integrated hydro-economic model to determine the drought and energy relationship in the Upper Euphrates Basin

ABSTRACT Decreasing precipitation in the Upper Euphrates Basin and the negative impact of climate change directly affect water resources and hydroelectricity generation in the basin. This basin, which contains the largest dams in terms of hydroelectricity generation potential, requires research studies to assess and characterize drought for risk prevention and mitigation applicable to water resources management. To better assess drought in the upper Euphrates Basin due to recent warming, FEHEM is developed, a hydro-economic optimization model of the integrated reservoir system of the Upper Euphrates Basin. Using a historical hydrological dataset, water management and hydroelectric operations are evaluated with a linear programming model at monthly time steps. This paper uses two different drought indices: (1) the standardized precipitation index, which is based on precipitation alone; and (2) the reconnaissance drought index, which takes into account both evaporation and precipitation. These indices were used to evaluate the impact of temporal drought characteristics in the Upper Euphrates Basin on the hydropower generation of 10 dams with a total installed capacity of over 3255 MW in the basin, based on 45 years of precipitation data from more than a hundred measuring stations in the basin.

Sensitivity analysis in the wavelet domain: a comparison study

Sensitivity analysis plays a pivotal role for the development and calibration of hydrological models, since they are often affected by equifinality. Despite a lot of effort has been placed for the development of effective sensitivity analysis methods, hydrological models remain over parametrized. We take advantage of the evidence that hydrological processes can be described as the superposition of effects occurring at different temporal scales (e.g., seasonal precipitation patterns, seasonal and daily snow and glacier melt, seasonal, daily and sub-daily water management operations) to develop a new framework to perform sensitivity analysis. We apply discrete and continuous wavelet transforms to disentangle hydrological signals occurring at different temporal scales and we take advantage of the different information stored at different temporal scales of the wavelet spectrum to perform a scale-dependent sensitivity analysis. This approach aims to increase the number of identifiable model parameters in comparison to standard sensitivity analysis performed in the time domain. As an exemplary problem, we apply the methodology to synthetic data describing surface water-groundwater interaction in rivers affected by hydropeaking (i.e., sudden fluctuations in the river stage due to hydropower production). The method could be applied also to other models displaying the superposition of processes with different intensities at different temporal scales such as ocean tide propagation in aquifers as well as snow and glacier melt models. The results indicate that considering multiple temporal scales allows us to increase the number of parameters that can be identified and hence calibrated with only a little increase in the computational effort.

Development of Upper Euphrates Basin hydro-economic model and hydropower generation optimization

Abstract Hydro-economic optimization models are common in hydropower reservoir modeling to aid system operators and planners. In these models, operations are driven by the economic value and constrained by the availability of water. The objective is to either minimize total costs or maximize total benefits. In this study, a hydro-economic optimization model for the integrated reservoir system of the Upper Euphrates Basin, with major tributaries providing water flow to the Euphrates River, is introduced. These model the 10 large-scale reservoirs of the basin with a total installed capacity of 3,255 MW. Water management and hydropower decision-making operations are evaluated with a piecewise linear programming algorithm in monthly time steps using a 45-year historical hydrology between 1971 and 2016. The model aims to maximize hydropower revenue over a long-term time horizon with energy prices varying by month. Reservoir storage and turbine release decisions are optimized for multiple hydropower plants connected in serial or parallel. Hydropower generation, revenue, reservoir storage, capacity ratios and generation reliability results are analyzed. Results show that these hydropower plants generate about 9,481 Gigawatt hour (GWh) of energy with an average turbine capacity use of 36% and obtain a revenue of 620 million $ per year.

Secretive marsh bird occupancy across a spectrum of hydroelectric reservoir management in western montane Canada

AbstractDam construction projects have created opportunities for water security, targeted flood protection, and energy production but at the cost of increasing anthropogenic pressure on affected aquatic ecosystems. Wetland ecosystems are often among the most vulnerable, as underlying hydrological regimes influence overall wetland structure and function. Marsh bird species are wetland and riparian habitat specialists, many of which are experiencing population declines across North America. We examined how the alteration of hydrological regimes for generating hydroelectric power affected the occurrence of secretive marsh bird species in the western montane region of British Columbia, Canada. We established survey stations in wetlands across 2 regions, the West Kootenay and the Columbia Wetlands, sampling across a spectrum of hydrological regimes and other potentially relevant factors. At each station, we assessed wetland occupancy during the breeding season using broadcast‐callback surveys focused on 5 secretive marsh bird species: American bittern (Botaurus lentiginosus), American coot (Fulica americana), pied‐billed grebe (Podilymbus podiceps), sora (Porzana carolina), and Virginia rail (Rallus limicola). Additionally, we measured vegetation structure and the proximity and size of nearby water bodies for each survey station. We then used occupancy models to assess important correlates behind wetland occupancy for these marsh bird species, considering water management operations, regional differences, and local‐ and landscape‐level wetland characteristics. Secretive marsh bird species were more likely to occupy wetlands in areas with less frequently altered hydrological regimes. Occupancy models highlighted local‐ and landscape‐level characteristics as important correlates for wetland occupancy by marsh birds. Wetlands with frequently altered hydrological regimes had more open water cover and less tall vegetation present, conditions that were negatively associated with occupancy. Altered wetlands in this study were farther from the next nearest wetland, which was also negatively associated with occupancy. We suggest reservoir management is altering vegetation communities within these wetlands, indirectly promoting lower occupancy of secretive marsh bird species.

The role of Renaissance dam in reducing hydrological extremes in the Upper Blue Nile Basin: Current and future climate scenarios

Climate change poses a great threat to society through its effects on extreme hydrological events (floods and droughts) and the sustainable development. Coping with climate change requires a better awareness of the possible impacts to inform climate adaptation strategies. In this study, we investigated the climate projections from two contrasting GCMs (wet scenario from MIROC5 and dry scenario from CSIRO) and quantified the possible outcomes in terms of hydrological components of the Upper Blue Nile Basin (UBNB). These two climate projection scenarios show that the overall precipitation change in the early (2011–2040), mid (2041–2070), and late century (2071–2100) over the UBNB may vary from –18.3 % to + 13.6 % of the baseline annual precipitation of 1350 mm. The hydrological simulations over the basin from our study showed that evapotranspiration may vary between –13.7 % and + 12.1 % of the average annual total actual ET of 710 mm, and the flow at the basin outlet may range between –40.7 % and + 30.8 % of the mean annual total flow volume of 45 billion cubic meters. As a result, the wet projection exhibited more frequent floods while the dry projection showed severe droughts, specifically in the late century. We also examined the role of the Grand Ethiopian Renaissance Dam (GERD), designed for hydropower generation, in moderating these potential future climate hydrological extremes. Our findings indicate that GERD operations can help reduce downstream flood and drought severity by managing flow releases. Thus, this study illustrates the most possible extreme hydrological events in the UBNB due to climate change and demonstrates the degree to which GERD operations can help reduce the impact of these extremes downstream. The findings and data generated in this study will aid understanding the importance of sustainable water management and reservoir operation that caters to both hydropower generation, and recurring floods and droughts.

An assimilated deep learning approach to identify the influence of global climate on hydrological fluxes

The rapid acceleration of the global water cycle caused by changes in global climate trigger complex processes that make conventional machine learning techniques limited in assessing impacts of such changes on terrestrial water storage (TWS). This study introduces an assimilated deep learning neural network to improve the modeling of TWS dynamics. Key predictors and inputs to this deep learning framework include runoff, rainfall, soil moisture, evapotranspiration, global teleconnection patterns and sea surface temperatures (SSTs). The proposed back propagation model in this study capitalizes on the availability of remotely sensed observations and model datasets to predict monthly TWS, a quantity that is difficult to observe in the field, but important for the estimation of regional water budget balance, and water resource management for agricultural purposes. By integrating pre-processed outputs from the Principal Component Analysis (PCA) and Independent Component Analysis (ICA) into our network using a deep neural pattern, we synthesized TWS from 2002 to 2017, and also made future predictions using our trained models. Results from these analyses showed that the ICA-BPNN model has a higher predictive accuracy compared to the PCA-BPNN. These models (ICA-BPNN and PCA-BPNN) were used to fit the three dominant temporal patterns of Gravity Recovery and Climate Experiment (GRACE) – observed TWS over Africa. Our simulation results from the testing phase indicate that the fits for the prediction of the first three leading modes of TWS for both models when compared to the observed GRACE-TWS were PCA-BPNN1 (89%), PCA-BPNN2 (82%), PCA-BPNN3 (84%) and ICA-BPNN1 (93%), ICA-BPNN2 (88%), ICA-BPNN3 (82%). The simulation fit of the BPNN corresponding to multi-annual time series, which are captured in the second and third orthogonal modes and localized patterns of TWS were lower than those of annual signals in both the PCA- and ICA-BPNN models. This was attributed to the fact that the multi-annual time series in GRACE-hydrological signals of our test-bed are complex compared to the annual patterns of TWS. On the one hand, this exemplifies the superior performance of our predictive framework in modeling naturalized system (annual changes in TWS driven by only climatic factors). On the other hand, the complexity in modelling multi-annual variations in TWS suggests heavily disturbed naturalized systems evidenced in the presence of human water management operations among other anthropogenic activities.

Water Storage Decisions and Consumptive Use May Constrain Ecosystem Management under Severe Sustained Drought

AbstractDrought has impacted the Colorado River basin for the past 20 years and is predicted to continue. In response, decisions about how much water should be stored in large reservoirs and how much water can be consumptively used will be necessary. These decisions have the potential to limit riverine ecosystem management options through the effect water‐supply decisions have on reservoir elevations. We used projected hydrology and river temperatures to compare the outcome of combinations of water storage scenarios and consumptive use limits on metrics associated with ecosystem management of the Colorado River in Grand Canyon. Ecosystem management metrics included the ability to implement designer flows, temperature suitability for fishes, and fragmentation. We compared current water management operations to prioritizing storage in either Lake Mead or Lake Powell combined with three levels of consumptive use. Projected reservoir levels limited environmental flow delivery and increased fragmentation regardless of where water was stored if consumptive use was not limited. Warmer river temperatures associated with low reservoir levels are likely, creating suitable conditions for non‐native species of concern, such as smallmouth bass. Water storage decisions provided variability and management flexibility, but water storage was less important when less water was available, highlighting the importance of keeping water in the system to provide flexibility for achieving ecosystem goals.

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The present study aimed to investigate the comparative growth performance and the eco-physiological response of tree species grown under intensive silvicultural management practices (Water management, drip fertigation, pruning, and thinning operations). The tree plantation was established in October, 2017 and maintained at Forest College and Research Institute, Mettupalayam, Coimbatore, India (11° 19’ N and 77°56’ E), with an altitude of 300 m above MSL and mean annual rainfall of 920.5 mm. The study was carried out with 3m x 2m in 7 different tree species namely Neolamarckia cadamba, Acrocarpus fraxinifolius, Grewia tiliaefolia, Melia dubia, Tectona grandis, Swietenia macrophylla, and Dalbergia sissoo. The biometric (Height and Diameter at Breast Height), biochemical (Chlorophyll) and physiological parameters (Photosynthesis rate and Transpiration rate) were measured at different ages under field conditions. The tree species namely Neolamarckia cadamba, Melia dubia, and Tectona grandis recorded the highest biometric observations, chlorophyll, photosynthesis rate, and transpiration rate. It is interesting to note that, even though Tectona grandis is a long rotation tree crop, the tree perform superior growth performance in early stages. Swietenia macrophylla showed poor performance in both the biometric and physiological parameters. The present study recommended that planting fast-growing tree species with short rotation can yield maximum biomasscompared to the long rotation trees if the tree plantation is appropriately managed with intensive silvicultural operations.

Integrated Duflow-Drainmod model for planning of water management operation in tidal lowland reclamation areas

The research objective was to develop field operational model to control water table level at reclaimed area of tidal lowland for food crop cultivation. DUFLOW computer model was used to evaluate the perfomance of water management network at secondary and tertiary levels, whereas DRAINMOD computer model is used to evaluate soil water status at tertiary block. Results of DUFLOW model simulation can be used to improve water management by passing the Secondary Irrigation Chanel (SPD) and Secondary Drainage Chanel (SDU) through tertiary channels, water gate installation of stop-log type and weir construction in Drainage Secondary Channel (SDU). The weir construction has function as long storage and capable to control or maintain soil water level in land not quickly drawdown. Drainmod simulation model is acceptable, this is indicated by the results of statistical analysis where the correlation coefficient value reaches 0.89. Analysis of DUFLOW-DRAINMOD computer model software showed mutually supportive results in which DUFLOW simulation results can provide water potential information in channel for supply purpose. This water level condition is an important part in DRAINMOD model because it has effect on soil water level dynamics as targeted on tertiary block as well as on capacity to applied drainage operation system.

Laboratory evaluation on temporary plugging performance of degradable preformed particle gels (DPPGs)

In recent years, granular temporary plugging agents (TPA) have been widely studied, especially in repeated fracturing operations, to stimulate oil and gas production in unconventional petroleum reservoirs. They can divert the hydraulic fracturing energy to form more complex fractures that make oil and gas more easily flow into production well. Pre-formed particle gels (PPGs), as deformable particles, are often used in petroleum reservoir water management operations because of their high strength, simple fabrication process, and environmental friendliness. However, their application as TPA is rarely reported. In this paper, degradable PPGs (DPPGs) were employed, and their temporary plugging performance was studied in the laboratory. Bottle tests were first conducted to investigate the swelling and degradation performance. Results show that DPPGs exhibit good swelling ability in an extended range of brine salinity (20000 to 400000 ppm), and DPPGs can be fully degraded, and the degradation time increase with temperature. According to the temporary plugging performance by core flooding experiments, the plugging strength increased with the injection pressure, dry particle size, and swelling ratio (less than 20 times). However, the addition of smaller size particles will prevent large particles from forming deformable blockage on the matrix end surface, and subsequent water flow channels will be easily created, so the plugging performance of the DPPGs will decrease. The above experimental results can provide an experimental and theoretical basis for the application of DPPGs in repeated fracturing operations in unconventional reservoirs.

Long-term river invertebrate community responses to groundwater and surface water management operations

River flow regimes have been transformed by groundwater and surface water management operations globally, prompting widespread ecological responses. Yet, empirical evidence quantifying the simultaneous effects of groundwater and surface water management operations on freshwater ecosystems remains limited. This study combines a multi-decadal freshwater invertebrate dataset (1995-2016) with groundwater model outputs simulating the effects of different anthropogenic flow alterations (e.g. groundwater abstraction, effluent water returns) and river discharges. A suite of flow alteration- and flow-ecology relationships were modelled that tested different invertebrate community responses (taxonomic, functional, flow response guilds, individual taxa). Most flow alteration-ecology relationships were not statistically significant, highlighting the absence of consistent, detectable ecological responses to long-term water management operations. A small number of significant statistical models provided insights into how flow alterations transformed specific ecological assets; including Ephemeroptera, Plecoptera and Trichoptera taxa which are rheophilic in nature being positively associated with groundwater abstraction effects reducing river discharges by 0-15%. This represents a key finding from a water resource management operation perspective given that such flow alteration conditions were observed on average in over two-thirds of the study sites examined. In a small number of instances, specific invertebrate responses displayed relative declines associated with the most severe groundwater abstraction effects and artificial hydrological inputs (predominantly effluent water returns). The strongest flow-ecology relationships were recorded during spring months, when invertebrate communities were most responsive to antecedent minimum and maximum discharges, and average flow conditions in the preceding summer months. Results from this study provide new evidence indicating how groundwater and surface water resources can be managed to conserve riverine ecological assets. Moreover, the ensemble of flow alteration- and flow-ecology relationships established in this study could be used to guide environmental flow strategies. Such findings are of global importance given that future climatic change and rising societal water demands are likely to further transform river flow regimes and threaten freshwater ecosystems.

Diadromous fish modified timing of upstream migration over the last 30 years in France

Abstract Numerous studies have documented a change in the phenology of migration of diadromous fish in response to climate change. Only few studies have, however, been conducted simultaneously for multiple species and at a large spatial scale. We investigated the change in the timing of upstream migration of diadromous fish species in France. We used an original dataset collected from 40 fish‐counting devices in 28 French rivers over 10–30 years for five diadromous taxa: Alosa spp., Anguilla anguilla (with a distinction between glass eel and yellow eel), Petromyzon marinus, Salmo salar, and Salmo trutta. Except for glass eel, we found that taxa shifted their migration for earlier arrival dates. This result is consistent with numerous studies reporting advancement of the phenology of species life‐events. On average, we highlighted a phenological change of −2.3 days per decade (min = −0.2, max = −3.7). Moreover, the North Atlantic Oscillation Index, sea surface temperature, air temperature, and river discharge were found to explain the timing of upstream migration of diadromous fish taxa, highlighting the importance of factors acting at different spatial scales. Given the important phenological changes observed in our study and more widely in the scientific literature, we recommend that managers incorporate these changes into the management rules; in particular, in the case of dams whose migratory transparency (i.e. the possibility for the fishes to cross the dam) is ensured by adaptive water management and gate operations. This study benefited from large‐scale monitoring of migratory phenology of multiple species and environmental variables. These monitoring data are valuable and could allow better predictive modelling of the response of species to climate change.

General Assessment of the Operational Utility of National Water Model Reservoir Inflows for the Bureau of Reclamation Facilities

This work investigates the utility of the National Oceanic and Atmospheric Administration’s National Water Model (NWM) for water management operations by assessing the total inflow into a select number of reservoirs across the Central and Western U.S. Total inflow is generally an unmeasured quantity, though critically important for anticipating both floods and shortages in supply over a short-term (hourly) to sub-seasonal (monthly) time horizon. The NWM offers such information at over 5000 reservoirs across the U.S., however, its skill at representing inflow processes is largely unknown. The goal of this work is to understand the drivers for both well performing and poor performing NWM inflows such that managers can get a sense of the capability of NWM to capture natural hydrologic processes and in some cases, the effects of upstream management. We analyzed the inflows for a subset of Bureau of Reclamation (BoR) reservoirs within the NWM over the long-term simulations (retrospectively, seven years) and for short, medium and long-range operational forecast cycles over a one-year period. We utilize ancillary reservoir characteristics (e.g., physical and operational) to explain variation in inflow performance across the selected reservoirs. In general, we find that NWM inflows in snow-driven basins outperform those in rain-driven, and that assimilated basin area, upstream management, and calibrated basin area all influence the NWM’s ability to reproduce daily reservoir inflows. The final outcome of this work proposes a framework for how the NWM reservoir inflows can be useful for reservoir management, linking reservoir purposes with the forecast cycles and retrospective simulations.

Riparian vegetation model to predict seedling recruitment and restoration alternatives

Native riparian vegetation communities have declined downstream of large water infrastructure like dams and diversions, owing to water management operations that prevent successful seedling colonization and recruitment. Altered timing and magnitude of reservoir releases to fulfill competing water demands often lead to reduced peak discharges and flow recession rates that do not support native riparian reproduction processes. To achieve short-term ecosystem function in highly regulated rivers an alternative method might be restoration planting, whereby success depends on identifying appropriate planting location and spatial extents. This study aims to provide a methodology to inform resource managers about the extent of possible natural seedling recruitment under average and wet hydrologic conditions, as well as constrain restoration planting operational uncertainties. Results from field surveys and simulations showed limited favorable areas for successful riparian seedling recruitment under regulated flows, regardless of hydrologic conditions in the basin. However, wet (11.4 ha) hydrologic conditions were more (approximately 11 times) favorable than average (1 ha) conditions for seedling recruitment. Furthermore, model results identified the location and spatial extent (25.6 ha) of favorable restoration planting areas during average flow. This extent is approximately 25 times larger than natural recruitment during an average (hydrological) year and even twice that for natural recruitment for a wet year. This suggests that ground operational activities guided by numerical modeling may effectively constrain planting uncertainties.

Water Balance of a Boreal Black Schist Heap Leach Operation

The current study presents the effect of process chemistry as well as climate conditions on the water balance of a heap leach operation for black-schist ore. The research is based on the actual water balance at the Terrafame (former Talvivaara) mine site in Finland during the years 2017 and 2018 (base case). In addition, scenarios with a deviation in climatic conditions (Antofagasta case), chemistry (non-heat generation case) and effects of climate change (RCP4.5 (representative concentration pathway) case and RCP8.5 case) were investigated. In the first case, the annual precipitation and evaporation were simulated for a highly arid climate such as in the Antofagasta Mountains, whereas in the second case, an assumption was made of no excess heat generation (exothermic reactions) in the heap reactions. The base case predicted a requirement of 9,000,000 m3 annual discharge of water from the site with the heaviest annual rainfall. The discharge requirement and therefore the water footprint of the plant was shown to be highly dependent on the climatic conditions, as the Antofagasta case predicted a discharge of water from the site as low as zero. Heat generation, typical of the reactions dominating in a boreal black-schist heap leach operation, was shown to be vital for water management operations and therefore discharge management in Nordic climatic conditions (the non-heat generation case), where the discharge requirement was shown to be nearly threefold compared to the base case (2018). If the black-schist ore body resided in Antofagasta, the freshwater consumption would be over eight times the current consumption in the base case in Finland. Climate change scenarios show that the changing climate would increase the range of variation but only increase the need for water discharge from the site by 5% in the wettest years, while raw water utilization would increase by 46 to 83% during the driest years. In general, the results highlight the issues related to the mass and energy balance of a heap leach nickel process, and therefore feasibility—showing that although the heat generation is ore- and process-specific, the water consumption as well as discharge to the surrounding environment is highly dependent on the climatic conditions (precipitation, temperature) in the geographical location.

Development of a modified floristic quality index as a rapid habitat assessment method in the northern Everglades.

Floristic quality assessments (FQA) using floristic quality indices (FQIs) are useful tools for assessing and comparing vegetation communities and related habitat condition. However, intensive vegetation surveys requiring significant time and technical expertise are necessary, which limits the use of FQIs in environmental monitoring programs. This study modified standard FQI methods to develop a rapid assessment method for characterizing and modeling change in wetland habitat condition in the northern Everglades. Method modifications include limiting vegetation surveys to a subset of taxa selected as indicators of impact and eliminating richness and/or abundance factors from the equation. These modifications reduce the amount of time required to complete surveys and minimizes misidentification of species, which can skew results. The habitat characterization and assessment tool (HCAT) developed here is a FQA that uses a modified FQI to detect and model changes in habitat condition based on vegetation communities, characterize levels of impact as high, moderate, or low, provide predictive capabilities for assessing natural resource management or water management operation alternatives, and uniquely links a FQI with readily accessible environmental data. For application in the northern Everglades, surface water phosphorus concentrations, specific conductivity, distance from canal, and days since dry (5-year average) explained 67% of the variability in the dataset with > 99.9% confidence. The HCAT approach can be used to monitor, assess, and evaluate habitats with the objective of informing management decisions (e.g., as a screening tool) to maximize conservation and restoration of protected areas and is transferable to other wetlands with additional modification.

Keys to Better Water Management: Seeking Sustainability Amid the Chaos

Here we go again. A series of unexpected circumstances have intersected to drive oil markets down, causing myriad challenges for operators and service companies alike. A virus pandemic erupts, shutting down global economies and thus the demand for oil. Ongoing disagreements between OPEC, Saudi Arabia, and Russia on a response strategy and increased production sees global crude prices drop to the $20 range, something we have not seen in decades. Compounding the crisis in North America is the market influence over the past few years, which drove operators to focus on cash flow and profitability over production and capital discipline with limited access to equity and additional debt. Operators will need to work closely with service providers to once again make step changes in optimizing value, improving efficiency, and eliminating downtime and wasted resources. The New Normal Speculation as to the duration of this crisis is just that: speculation. The macro forces fueling it, the COVID-19 pandemic, and the price war between OPEC and Russia are beyond our control. In terms of business, it is wiser and more prudent to focus on what we can control. Even before the recent events, most operators and service providers had already been revising their strategies, shifting from production growth to profit growth, in response to dwindling investment. We can expect that trend to intensify. There will be an increased emphasis on making operations more efficient and leaner with fewer resources and less susceptible to incidents and interruptions that lead to downtime. Further, investors are continuing to prioritize ESG factors (environment, social, and governance) alongside profitability. The room for error and cost overruns just got a lot smaller. It is a well-worn cliché but perfectly apt right now: When life gives you lemons, make lemonade. As challenging as the current market climate is, it nonetheless presents us with opportunities to adopt more sustainable and more efficient solutions; among them is better water management. Given the ratio of produced water to oil—up to 10 bbl for every 1 bbl of oil—development of unconventional assets has required increasing the focus on water management operations. To hydraulically fracture a single well requires millions of gallons of water, water that is frequently sourced elsewhere and transported to the fracturing site via truck. Hydraulic fracturing produces millions of barrels of water from the reservoir in addition to the oil. The produced water, along with any recovered frac water (flowback), contains sands, salts, and metals that make it challenging to reuse directly in fracturing or otherwise. The more sustainable and more efficient solution is to recycle the flowback and produced water. It entails desanding, filtering, and treating the flowback and produced waters, blending it to applicable specifications, safely storing it, and finally transferring the recycled water to the wellsite for use as a fracturing fluid. A comprehensive, integrated, and automated closed-loop water management system can render flowback and produced water into a suitable base fluid for fracturing. Such a system not only brings more sustainability, accuracy, and efficiency to water management, it is cost-effective, especially now amid this volatile market.

What do economic water storage valuations reveal about optimal vs. historical water management?

What is the economic value of storing water for future droughts, and what are the consequences of this valuation for water management? One way to answer this question is to ask: ‘what is the valuation, which if used, would maximize a region's economic use of water?’ This prescriptive valuation can be done by linking classical hydro-economic models to global search methods. Another way to answer this question is to ask: ‘what do historical water management operations reveal about water's economic value?’ Indeed, past reservoir uses reveal the empirical inter-temporal valuations of past water managers. Although they may not have been optimized in a formal sense, in mature water resource systems with economic water demands, reservoir storage rules evolve via a socio-political process to embody societies' valuation of water. This empirical, ‘positive’, or descriptive valuation is captured by calibrating a hydro-economic model such that carry-over storage value functions enable simulated storage to match a historical benchmark. This paper compares both valuations for California's Central Valley revealing that carryover storage values derived from historical operations are typically greater than prescribed values. This leads to a greater reliance on groundwater use in historical operations than would have been achieved with system-wide optimization. More generally, comparing the two approaches to water valuations can provide insights into managers' attitudes as well as the impact of regulatory and institutional constraints they have to deal with – and that are not necessarily included in optimization models.

HISTORY OF DEVELOPMENT, PROSPECTS OF CONSTRUCTION, RECONSTRUCTION AND REHABILITATION OF RECLAMATION SYSTEMS

Purpose of research. To analyze the basic tendencies and prospects of the development of construction, reconstruction and restoration of irrigation and drainage systems in Ukraine and to outline the main areas of researches and achievements of Reclamation Department of the Institute on the issues of reliable and effective functioning of water management and reclamation complex.
 Research Method - Analytical, Statistical.
 Study results and main findings. The article analyzes the current state of the irrigation and drainage sector in Ukraine in the context of climate change and emphasizes its decisive role in obtaining stable and predictable crop yiels, increasing land productivity and further developing agricultural production. The history of development and the nascent stages of the scientific departments of the Institute of Hydraulic Engineering and Land Reclamation (now the Institute of Water Problems and Land Reclamation of the National Academy of Sciences of Ukraine) dealt with the issues of water management construction, operation, maintenance, repair and restoration of the engineering infrastructure of irrigation and drainage systems, sprinkling equipment, hydraulic structures and equipment were considered. The results of multi-year researches, main areas of scientific activity, developments and achievements of the specialists of the departments of irrigation and drainages, operation of water management and drainage systems, drainage and irrigation reclamation of the Institute on the issues of reliable and efficient functioning of water and land reclamation complex were systematized. Technical and technological basis for improving the infrastructure of irrigation and drainage systems were justified and the ways of solving the existing problems were proposed. It was noted that at present, given climate change and management conditions, increasing productivity and sustainability of agriculture requires searching for new scientific, methodological, technical and technological approaches to the restoration and further development of irrigation and drainage.
 Prospects. At the same time, reforming the management of the water sector supported by an appropriate legislative framework and the active involvement of water users in management processes is a prerequisite. The necessity of implementing the provisions and measures proposed in the “Irrigation and Drainage Strategy of Ukraine for the Period until 2030”, prepared with the participation of the specialists from IWPLR NAAS, was emphasized, which will contribute to the effective use of irrigation and drainage systems potential to increase the agricultural production in the conditions of climate change.