Adaptive Water Resources Management Research Articles

Climate change projection using statistical downscaling model over southern coastal Iran

Iran is highly vulnerable to climate change, particularly evident in shifting precipitation and temperature patterns, especially in its southern coastal region. With these changing climate conditions, there is an urgent need for practical and adaptive management of water resources and energy supply to address the challenges posed by future climate change. Over the next two to three decades, the effects of climate change, such as precipitation and temperature, are expected to worsen, posing greater risks to water resources, agriculture, and infrastructure stability. Therefore, this study aims to evaluate the alterations in mean daily temperature (Tmean) and total daily rainfall (rrr24) utilizing climate change scenarios from both phases 5 and 6 of the Coupled Model Inter-comparison Project (CMIP5 and CMIP6, respectively) in the southern coastal regions of Iran (Hormozgan province), specifically north of the Strait of Hormuz. The predictions were generated using the Statistical Downscaling Model (SDSM) and National Centre for Environmental Prediction (NCEP) predictors, incorporating climate change scenarios from CMIP5 with Representative Concentration Pathways (RCPs) 2.6, 4.5, and 8.5 and CMIP6 with Shared Socioeconomic Pathways (SSPs) 1, 2, and 5. The analysis was conducted for three distinct time periods: the early 21st century (2021–2045), middle 21st century (2046–2071), and late 21st century (2071–2095). The results indicated that the CMIP5 model outperformed the CMIP6 model in simulating and predicting Tmean and rrr24. In addition, a significant increase in Tmean was observed across all the scenarios and time periods, with the most pronounced trend occurring in the middle and late 21st century future periods. This increase was already evident during the base period of 2021–2045 across all scenarios. Moreover, the fluctuations in precipitation throughout the region and across all scenarios were significant in the three examined future periods. The results indicated that among CMIP5 scenarios, RCP8.5 had highest changes of Tmean (+1.22 °C) in Bandar Lengeh station in 2071–2095 period. The lowest change magnitude of Tmean among CMIP5 scenarios was found in RCP4.5 (−1.94 °C) in Ch station in 2046–2070 period. The results indicated that among CMIP5 scenarios, RCP8.5 had highest changes of rrr24 (+150.2 mm) in Chabahar station in 2071–2095 period. The lowest change magnitude of rrr24 among CMIP5 scenarios was found in RCP8.5 (−25.8 mm) in Bandar Abbas station in 2046–2070 period. In conclusion, the study reveals that the coastal area of Hormozgan province will experience rising temperatures and changing rainfall patterns in the future. These changes may lead to challenges such as increased water and energy consumption, heightened risks of droughts or floods, and potential damage to agriculture and infrastructure. These findings offer valuable insights for implementing local mitigation policies and strategies and adapting to emerging climate changes in Hormozgan's coastal areas. For example, utilizing water harvesting technologies, implementing watershed management practices, and adopting new irrigation systems can address challenges like water consumption, agricultural impacts, and infrastructure vulnerability. Future research should accurately assess the effect of these changes in precipitation and temperature on water resources, forest ecosystems, agriculture, and other infrastructures in the study area to implement effective management measures.

Attribution discernment of climate change and human interventions to runoff decline in Huangshui River Basin, China

Abstract To achieve sustainable development goals in Huangshui River Basin (HRB), strengthening adaptive water resources management under the dual impact of climate change (CC) and human interventions (HI) is of great significance. Multiple mathematical and statistical methods were employed to determine the runoff trend and breakpoint in HRB. The elasticity of CC and HI on the runoff decline and their contributions were quantitatively discerned based on the Budyko hypothesis, complementary method, and SWAT hydrological model. The results show that (1) the runoff showed a decreasing trend, with a runoff breakpoint in 1990; (2) the elasticity coefficients indicated a 1% increase in P, ET0, and n, leading to a 2.19% increase, a 1.19% decrease, and a 1.52% decrease in the runoff, respectively; (3) the Budyko framework determined the contribution of CC and HI to runoff decline in HRB to be 37.98–41.86% and 58.14–62.02%, respectively, and that estimated by SWAT hydrological model to be 38.72 and 61.28%, respectively; (4) HI were the primary factor for runoff decline in HRB, where direct anthropogenic disturbances such as water withdrawals and water conservancy project construction were the main drivers. The findings have important scientific significance for water resources planning and management in HRB.

Estimation and attribution of water storage changes in regulated lakes based on Budyko’s supply–demand framework

Study regionLake Dianchi, southwest China Study focusUnderstanding changes in lake water storage (LWS) and its attribution to climate change and human activities is essential for adaptive management of water resources in regulated lakes. Although altimetric measurements, whether ground- or satellite-based, can reproduce LWS dynamics, they do not provide sufficient information on why LWS is changing. Neither the water balance method nor detailed hydrological modeling can capture exactly LWS change in most regulated lakes largely because of the scarcity of water output observations. Here, a simple water balance model, following Budyko’s supply–demand framework, was proposed to estimate LWS change in regulated lakes without the need for water output information. The elasticity of LWS was theoretically derived from the Budyko-type model to attribute LWS change to its main driving factors. New hydrological insights for the regionApplication of the proposed model to the Lake Dianchi for the period 1964–2022 indicated that the model accurately captured the variations of annual LWS in Lake Dianchi with a relative root mean square error of 4.23%, and correlation coefficient of 0.77. The attribution results suggested that lake regulation strategies were the chief determinant of LWS change in Lake Dianchi, while water transfer had a limited contribution. This study suggests that complex hydrological behavior in regulated lakes can be explored using Budyko's supply–demand framework with a low requirement for data.

Adaptive management of water resources system in the arid Aksu river basin, northwest China

Due to changing environments, the conflict between water supply and demand in arid northwest China is becoming increasingly prominent, resulting in the water security challenges and the need for risk management. Therefore, this study aimed at developing an adaptive management approach for the compound systems of water ecology and socioeconomics in the Aksu River Basin (ARB), a typical northwest arid watershed in China. This strategy aimed to reduce risk based on an adjusted water resource management system with the stringent controls (i.e., total water consumption, water use efficiency, and minimum ecological water satisfaction rate controls ‘three red lines’). The main findings are as follows: (1) Although the water resource system in the ARB is currently at low risk state, it could be subjected to higher risk levels in future scenarios. (2) An adjusted “three red lines” policy should be utilized to ensure adaptive management of risk in the water resource system. The corresponding coefficients for each “red line” was 8.37, 10.78, and 0.609, respectively. (3) Following a nonlinear multi-objective management, the vulnerability and risk decreased significantly, by −100% and −50%, respectively, whereas the resilience of the water resource system increased significantly, up to 330%. Therefore, adaptive water resource management is vital in reducing water resource risk, and is important for understanding the status of regional water resource systems and solving water security problems in a changing environment.

Reassessment of the declines in the largest freshwater lake in China (Poyang Lake): uneven trends, risks and underlying causes

Water level decline in the largest freshwater lake in China (Poyang Lake) has raised grave concerns and continuous debates regarding the proposal of a water control project. Previous hydrologic investigations on the water level decline in Poyang Lake were conducted mostly during recession season and typical dry years and hence lacked the comprehensive view of associated risks and possible spatial heterogeneity of trend during low water level periods. The present study reassessed the long-term trend and regime shift of low water level variations and their associated risks based on hydrological data across multiple stations in Poyang Lake during 1952–2021. The underlying causes of the trends of water level decline were further investigated. Results showed uneven trends and risks of water level variations in different seasons and across different lake regions. The water level of all five hydrological stations in Poyang Lake significantly dropped in the recession season, and the risks of water level decline evidently increased since 2003, which could be largely attributed to the water level drop in the Yangtze River. In terms of the dry season, clear spatial differences of long-term trend of water level were found, with water level in the central and southern lake regions significantly dropping, which was probably caused by dramatic bathymetry undercutting in the central and northern lake regions. In addition, the impacts of topographic changes became significant when water level of Hukou fell below 13.8 and 11.8m for the northern and southern lake regions, respectively. By contrast, water level in the northern lake region showed increasing trends in the dry season. In addition, only the occurrence time of water level under moderate risk significantly advanced for all stations except for Hukou. The present study could provide a full picture of low water level trends, associated risks across different lake regions and underlying causes in Poyang Lake, thus providing insights into adaptive water resources management.

Evolution of a river management industry in Australia reveals meandering pathway to 2030 UN goals

Globally, river management is a multi-billion-dollar industry. The United Nations (UN) Decade of Ecosystem Restoration calls for accelerated action towards integrated, participatory, and adaptive water resources management. Here we test whether the required shifts are occurring in the Australian stream management industry, an environmental management industry in a developed western nation. We undertook structured review and topic modelling of 958 peer-reviewed papers presented at the national stream management conference from 1996-2021. We investigated trends in collaboration, transdisciplinary knowledge, diversity of input and perspectives, adaptive management, interaction with policy, and responses to natural events. We found that the industry has matured over the past 25 years, with increasing collaboration, diversity and interdisciplinarity. However, there was no measurable increase in on-ground community participation or use of adaptive management. The findings highlight opportunities for the industry to mature further to achieve UN 2030 goals for integrated water resource management and ecosystem restoration.

Evolutionary Characteristics of Runoff in a Changing Environment: A Case Study of Dawen River, China

Watershed water cycles undergo profound changes under changing environments. Analyses of runoff evolution characteristics are fundamental to our understanding of the evolution of water cycles under changing environments. In this study, linear regression, moving average, Mann–Kendall, Pettitt, accumulative anomaly, STARS, wavelet analysis, and CEEMDAN methods were used to analyze the trends, mutations, and periodic and intrinsic dynamic patterns of runoff evolution using long-term historical data. The intra-annual distribution of runoff in the Dawen River Basin was uneven, with an overall decreasing trend and mutations in 1975–1976. The main periods of runoff were 1.9 and 2.2 years, and the strongest oscillations in the study period occurred in 1978–1983. The runoff decomposition high-frequency term (intra-annual fluctuation term) had a stronger fluctuation frequency, with a period of 0.51–0.55 years, while the low-frequency term (interannual fluctuation term) had a period of 1.55–2.26 years. The trend term for the runoff decomposition tended to decrease throughout the monitoring period and gradually stabilized at the end of the monitoring period, while the period gradually decreased from upstream to downstream. In summary, we used multiple methods to analyze the evolutionary characteristics of runoff, which are of great relevance to the adaptive management of water resources under changing environments.

Spatiotemporal variation of rainfall and its implications on water resources management: The case of Manyame River catchment in Zimbabwe

AbstractRainfall is an important hydrometeorological variable that affects river flow regimes and the amount of water flowing into surface water bodies and underground aquifers. Changing rainfall patterns and magnitudes contribute to extreme events including floods, droughts, and landslides. Thus, understanding of rainfall distribution is vital to sound water resources planning and allocation to users. Owing to the shortage of evenly distributed of rainfall stations in the arid and semiarid catchments, satellite rainfall products are regarded as reliable alternatives. This study therefore analyzes the long‐term spatiotemporal variation of rainfall in Manyame River catchment in Zimbabwe. Monthly rainfall data spanning from 1982 to 2019 were retrieved from the Climate Hazards Group Infra‐Red Precipitation with Station (CHIRPS). In situ rainfall data obtained from the country's two Meteorological Services Department were used to determine the accuracy of satellite data. Rainfall trends were tested using the Mann–Kendall trend test. The results showed goodness of fit between in situ and remotely sensed rainfall data. There is no significant increasing and decreasing trends in quarterly, monthly, and wet season rainfall. Statistically significant decreasing trends were observed in the central parts of the catchment during the dry season. The changing rainfall trends highlight the need for integrated and adaptive water resource management strategies to avoid adverse effects of floods and droughts in the catchment.

Multi-objective optimization of winter irrigation for cotton fields in salinized freeze-thaw areas

The adaptive management of saline-alkali land and water resources can effectively alleviate land degradation and water depletion, and appropriate irrigation can improve crop yield and production efficiency. Based on the soil changes and comprehensive crop benefits under different initial soil environments, the optimization of the irrigation amount of cotton in saline-alkali areas is of great significance for the improvement of agricultural production of these areas in developing countries and even worldwide. The responses of farmland with various degree of salinization to different winter irrigation amounts in seasonal freeze-thaw arid areas should therefore be further explored. In this study, the soil moisture-temperature-salinity changes and the crop growth responses of three cotton fields with different salinization levels (5.15, 8.17, and 11.15 g·kg-1) under four winter irrigation amounts (0, 3000, 3600, and 4200 m3·ha-1) were intensively investigated via a two-year field experiment in Xinjiang Province, China. The results demonstrate that winter irrigation significantly improved the soil moisture-temperature-salinity environment during the freeze-thaw period, and the influence was affected by the field salinization level. The initial salinity of salinized field promoted soil thawing and water storage, and inhibited soil freezing and salt leaching. The intraspecific relationship of salinized cotton fields changed from competition to promotion under winter irrigation, and soil salinity weakened the optimization of the intraspecific relationship. The multiple correlations between the benefit indexes of cotton were significantly strengthened under winter irrigation, and the negative effect of the soil salinization level on the cotton benefit indexes was stronger than that of the winter irrigation amount. Based on a multiple regression analysis, the optimal winter irrigation amounts for cotton fields with mild, moderate, and severe salinization were found to be 3416.83–4256.14, 4256.14–6502.96, and 6502.96–9614.24 m3·ha-1, respectively. This research provides a theoretical basis for determining the appropriate winter irrigation amount for cotton fields with various degrees of salinization in seasonal freeze-thaw arid regions.

Climate Change Impacts on Runoff in the Fujiang River Basin Based on CMIP6 and SWAT Model

Understanding the responses of the hydrological cycle and extreme events to climate change is essential for basin water security. This study systematically assessed climate change impacts on runoff and floods in the Fujiang River basin, which is the main tributary of the upper Yangtze River, China, using the Soil Water Assessment Tool (SWAT) driven by the latest climate simulation of 14 General Circulation Models (GCMs) under two Shared Socioeconomic Pathways (SSP2-4.5 and SSP5-8.5). This study indicates a generally warmer and wetter climate projected in the Fujiang River basin, and correspondingly an overall increase in projected ensemble annual mean runoff, monthly runoff, monthly high flow (Q05), and monthly low flow (Q95) in the periods of 2021–2060 and 2061–2100, with the long-term period being more substantial than that of the near future, especially for SSP5-8.5. However, the projected changes in monthly runoff show a large spread across GCMs, with greater increases mainly occurring in the early rainy season. Most of the GCMs show that projections of Q95 will substantially increase compared to Q05. The intensity and frequency of floods with a 30-year return period are likely to increase, especially under SSP5-8.5. Despite the uncertainties in projected future changes in runoff, these findings highlight the complexity of runoff response to climate change, promoting the need for adaptive water resource management.

Future changes in annual runoff and hydroclimatic extremes in the upper Yangtze River Basin

The upper Yangtze River Basin (UYRB) provides almost half of the total runoff volume of the entire Yangtze River and is of great importance for the population living in the upstream and downstream regions. The recent streamflow decline and more frequent hydroclimatic extremes have raised concerns about the water sustainability and water security of the UYRB in a changing climate. Here we examine the hydrological changes in the UYRB during the historical period (1961–2020) and the future period (2021–2070) using a physically-based hydrological model. Based on the simulation results, the future changes in water resources and hydroclimatic extremes in the UYRB were analyzed. The results show that the mean annual runoff volume in the UYRB during the future period will further decrease by 20.4 (SSP1-2.6), 17.7 (SSP2-4.5) and 22.0 (SSP5-8.5) billion m3 compared with the historical mean value. The agricultural drought severity will increase in all sub-regions, which tends to be more severe than the meteorological droughts, and Wujiang is going to experience the largest increase in drought severity. Averaged across the UYRB, the unprecedented agricultural droughts and pluvials will occur more than once per decade on average in the future, indicating that the most extreme events in the historical period would become the new normal in the future. The design floods with different return periods at all major hydrological stations in the UYRB are projected to increase, and in the future there will be more frequent drought-pluvial seesaws at the major hydrological stations. These findings highlight the importance of adaptive water resources management to tackle the elevated risk of water shortage and more frequent and severe hydroclimatic extremes in the future UYRB.

Adaptation of water resources management under climate change

The rapid growth of demand in agricultural production has created water scarcity issues worldwide. Simultaneously, climate change scenarios have projected that more frequent and severe droughts are likely to occur. Adaptive water resources management has been suggested as one strategy to better coordinate surface water and groundwater resources (i.e., conjunctive water use) to address droughts. In this study, we enhanced an aggregated water resource management tool that represents integrated agriculture, water, energy, and social systems. We applied this tool to the Yakima River Basin (YRB) in Washington State, USA. We selected four indicators of system resilience and sustainability to evaluate four adaptation methods associated with adoption behaviors in alleviating drought impacts on agriculture under RCP4.5 and RCP 8.5 climate change scenarios. We analyzed the characteristics of four adaptation methods, including greenhouses, crop planting time, irrigation technology, and managed aquifer recharge as well as alternating supply and demand dynamics to overcome drought impact. The results show that climate conditions with severe and consecutive droughts require more financial and natural resources to achieve well-implemented adaptation strategies. For long-term impact analysis, managed aquifer recharge appeared to be a cost-effective and easy-to-adopt option, whereas water entitlements are likely to get exhausted during multiple consecutive drought events. Greenhouses and water-efficient technologies are more effective in improving irrigation reliability under RCP 8.5 when widely adopted. However, implementing all adaptation methods together is the only way to alleviate most of the drought impacts projected in the future. The water resources management tool helps stakeholders and researchers gain insights in the roles of modern inventions in agricultural water cycle dynamics in the context of interactive multi-sector systems.

Runoff response to changing environment in Loess Plateau, China: Implications of the influence of climate, land use/land cover, and water withdrawal changes

The influence of climate change and human interference bring high nonstationary characteristics that are different from the original long-term stable state. So that, investigating runoff variation and attribution under changing environments is important for implementing adaptive management of global water resources, especially on the interannual scale. In this study, the attribution of measured runoff change in the Wuding River Basin (WRB) of the Loess Plateau, China, was studied using the elasticity method based on the Budyko framework and groundwater storage change analysis on an interannual scale. The change in the measured runoff driven factors was divided into three categories: climate change, human-induced land use/land cover (HI-LULC) change, and water withdrawal change. The results show that the contribution rate of climate change was the largest (with the mean value 54.07%), followed by the HI-LULC change (with the mean value 43.85%), and the minimum is WW change (with the mean value 2.08%). Climate change had a maximum contribution to runoff change, of which precipitation was dominant, followed by relative humidity, net radiation, and wind speed; air temperature had a minimal impact. In addition, the ecological change tendency was analyzed by combining HI-LULC and NDVI data. The analysis results of ecological change tendency indicate that the policy implementation of soil and water erosion control caused the ecological restoration to some extent, but also led to a decrease in runoff. This study provides scientific and useful information for the conservation of water and soil, runoff prediction, and sustainable water resource management in the WRB, and enriches the knowledge of contribution analysis of runoff variation which can be referenced by other basins across the globe.

The Importance of Legislative Reform to Enable Adaptive Management of Water Resources in a Drying Climate

In South Australia’s Eyre Peninsula, groundwater provides 85% of the region’s reticulated water supply. Fresh groundwater resides within shallow karstic limestone aquifers recharged by incident rainfall. Water levels are very responsive to short-term climate variability and are at risk of sustained decline due to long-term drying trends and the further rainfall declines indicated by projections of future climate, thereby increasing risk to water security and groundwater-dependent ecosystems. In 2009, a new adaptive resource management approach was enabled through legislative reform that better addresses climate variability, particularly where aquifer robustness is low. This allows the volume of water available for licensed allocations to be varied annually depending on the current condition of the aquifer resources. A three-tiered trigger level policy varies the rate at which water allocations are limited in proportion to monitored changes in groundwater storage. The three trigger thresholds are specified for each discrete groundwater resource, based on levels of risk. We now have more than five years of observations and practice of this approach to learn of its efficacy and consequences for water users, the water resources, and the environment. It has proved to be an effective way to deal with the uncertainties in how and when climate may change and how water management principles can effectively respond. Our case study provides an example of the importance of legislative reform to enable adaptive water resource management to effectively tackle the challenges of water planning in a drying climate.

Spatiotemporal Trend Analysis of Temperature and Rainfall over Ziway Lake Basin, Ethiopia

Rainfall and temperature trends detection is vital for water resources management and decision support systems in agro-hydrology. This study assessed the historical (1983–2005) and future (2026–2100) rainfall, maximum temperature (Tmax), and minimum temperature (Tmin) trends of the Ziway Lake Basin (Ethiopia). The daily observed rainfall and temperature data at eleven stations were obtained from the National Meteorological Agency (NMA) of Ethiopia, while simulated historical and future climate data were obtained from the Coupled Model Intercomparison Project 5 (CMIP5) datasets under Representative Concentration Pathways (RCP) of 4.5 and 8.5. The CMIP5 datasets were statistically downscaled by using the climate model data for hydrologic modeling (CMhyd) tool and bias corrected using the distribution mapping method available in the CMhyd tool. The performance of simulated rainfall, Tmax, and Tmin of the CMIP5 models were statistically evaluated using observation datasets at eleven stations. The results showed that the selected CMIP5 models can reasonably simulate the monthly rainfall, Tmax, and Tmin at the majority of the stations. Modified Mann–Kendall trend test were applied to estimate the trends of annual rainfall, Tmax, and Tmin in the historical and future periods. We found that rainfall experienced no clear trends, while Tmax, and Tmin showed consistently significant increasing trends under both RCP 4.5 and 8.5 scenarios. However, the warming is expected to be greater under RCP 8.5 than RCP 4.5 by the end of the 21st century, resulting in an increasing trend of Tmax and Tmin at all stations. The greatest warming occurred in the central part of the basin, with statistically significant increases largely seen by the end of the 21st century, which is expected to exacerbate the evapotranspiration demand of the area that could negatively affect the freshwater availability within the basin. This study increases our understanding of historic trends and projected future change effects on rainfall- and evapotranspiration-related climate variables, which can be used to inform adaptive water resource management strategies.

Impact Assessment of Climate Change on the Near and the Far Future Streamflow in the Bocheongcheon Basin of Geumgang River, South Korea

Highly concentrated precipitation during the rainy season poses challenges to the South Korean water resources management in efficiently storing and redistributing water resources. Under the new climate regime, water resources management is likely to become more challenging with regards to water-related disaster risk and deterioration of water quality. To alleviate such issues by adjusting management plans, this study examined the impact of climate change on the streamflow in the Bocheongcheon basin of the Geumgang river. A globally accepted hydrologic model, the HEC-HMS model, was chosen for the simulation. By the calibration and the validation processes, the model performance was evaluated to range between “satisfactory” and “very good”. The calibrated model was then used to simulate the future streamflow over six decades from 2041 to 2100 under RCP4.5 and RCP8.5. The results indicated significant increase in the future streamflow of the study site in all months and seasons over the simulation period. Intensification of seasonal differences and fluctuations was projected under RCP 8.5, implying a challenge for water resources managers to secure stable sources of clean water and to prevent water-related disasters. The analysis of the simulation results was applied to suggest possible local adaptive water resources management policy.

Thermodynamic response of precipitation extremes to climate change and its impacts on floods over China

<p indent=0mm>As the planet warms, shifts in the thermodynamic and dynamic environments of the climate system exert substantial impacts on the energy budget and water cycle. Understanding the response of precipitation extremes to climate change is essential for mitigating weather-related hazards and facilitating adaptive water resources management. The moisture holding capacity of the atmosphere, governed by the Clausius-Clapeyron (C-C) relationship, increases with temperature at a rate of about 7%/°C. Thermodynamically, precipitation intensity is expected to increase exponentially and worsen flood conditions with atmospheric warming. However, both observational and satellite data have revealed a nonmonotonic (hook) scaling of precipitation and storm runoff, in which extremes strengthen with warming temperature up to a peak point (<italic>T</italic>_pp) and decline thereafter. Few studies have yet considered whether and why the hook structure might change in a future warming climate. Moreover, existing studies have largely failed to detect and attribute changes of extreme precipitation to atmospheric thermodynamics versus dynamics, limiting reliable projection of future hydrological hazards and climate simulations. Here, we build upon existing studies to understand how precipitation and storm runoff scaling might change over Chinese mainland. We use gridded observational data to examine the temperature scaling of precipitation and storm runoff extremes, extending the C-C relationship. Using the ERA5 reanalysis dataset, we diagnose the impacts of total column water vapor (TCWV), convective available potential energy (CAPE) and relative humidity on precipitation extremes. After partitioning the thermodynamic and dynamic contributions of precipitation extremes based on the energy budget and water vapor balance, we quantify the underlying physical mechanisms of hook structures. Future climate scenarios are projected by using a large ensemble from 21 global climate models (GCMs) within Coupled Model Inter-comparison Project Phase-6 (CMIP6). Future streamflow series of 151 basins are projected by forcing hydrological model with bias-corrected climate model outputs. We quantify changes in the hook structures and their <italic>T</italic>_pp, and investigate implications of these shifts for future storms and flooding. The results show that relative humidity usually decreases with warming near-surface temperatures over most areas of China, while the TCWV and CAPE exhibit positive scaling rates with temperatures. The ERA5 reanalysis data over China reveals that atmospheric dynamics are responsible for the intensification of precipitation extremes and even flooding under very warm temperatures. The daily bias correction method reduces the systematical biases of GCMs outputs adequately, and captures extreme precipitation and temperatures well. By using four different hydrological models, we find that the Xinanjiang model typically exhibits the best performance in simulating daily streamflow over Chinese mainland. Projections of future hydro-climatological scenarios indicate that the hook structures do not set a firm upper-bound constraint on the intensification of extremes; rather, both the hook structure and the <italic>T</italic>_pp shift toward warmer temperatures in a warming climate. Alongside the shifts in <italic>T</italic>_pp, future storm and flooding extremes are projected to intensify by 20%−30%. These findings highlight the urgency in enhancing societal resilience to climate change, and understanding how the intensification of weather-related hazards might affect existing infrastructure and ecosystems.

A holistic water monitoring approach for an effective ecosystem management

Eutrophication is one of the most pressing problems affecting water quality. As a consequence, harmful algae blooms (HABs) are intensifying their occurrence in many aquatic ecosystems around the world. Under this water quality risk scenario, long term monitoring arises as a need to recognize, understand and anticipate the HABs outbreaks. However, existing monitoring methodologies are limited when dealing with HABs, thus forcing to make assumptions and decisions based on interpolated and inconsistent data. This conceptual paper attempts to highlight the importance of moving towards an integrated water monitoring methodology, where manual sampling, on-site automatic high-frequency monitoring (AHFM) and remote sensing are aligned to facilitates decision-making. In addition, because of the key role of microbial communities on the drift of aquatic ecosystems and water quality, they should be considered as a key element in HABs monitoring and management programs. In this manner, the biotic knowledge could be integrated into coordinated response plans as ecosystem management tools. Therefore, this holistic approach could provide decision makers and stakeholders an adaptive water resource management grounded on the theory of ecohydrology.

Runoff response to directional land cover change across reference basins in the conterminous United States

Land cover change plays a critical role in influencing hydrological responses. Change in land cover has impacted runoff across basins with substantial human interference; however, the impacts in basins with minimal human interference have been studied less. In this study, we investigated the impacts of directional land cover changes (forest to/from combined grassland and shrubland) in runoff coefficient (RC; ratio of runoff to precipitation) and runoff volume across 603 low human interference reference basins in the conterminous United States (CONUS). The results indicate basins with significant (p<0.05) increasing trends in runoff and RC were across the northeast and northwest regions of CONUS, and basins with decreasing trends were in the southern CONUS region. A unit percent increase in basin area from grassland and shrubland to forest was associated with a ∼4% decrease in RC across basins with decreasing RC trends. Similarly, a unit percent increase in basin area from forest to a combined grassland and shrubland was associated with a ∼1% increase in RC across increasing RC trend basins. Runoff volume was decreased (increased) by ∼25 × 106 m3 yr−1 (∼9 × 106 m3 yr−1) across basins with decreasing (increasing) trends in runoff and RC. When relating runoff volume with the area of directional land cover changes, each 1 km2 increase in area from grassland and shrubland to forest resulted in a decrease of ∼530,000 m3 runoff volume across basins with decreasing trends. In contrast, each 1 km2 increase in area from forest to grassland and shrubland increased runoff volume by ∼200,000 m3 across increasing trend basins. Basins in the southern region of CONUS were more impacted by runoff parameters (RC and runoff volume) from directional land cover changes than basins in the northern region. The findings of this study are useful for planning and managing water availability for sustainable and adaptive water resources management at regional scales.

Spatial and Temporal Shifts in Historic and Future Temperature and Precipitation Patterns Related to Snow Accumulation and Melt Regimes in Alberta, Canada

Shifts in winter temperature and precipitation patterns can profoundly affect snow accumulation and melt regimes. These shifts have varying impacts on local to large-scale hydro-ecological systems and freshwater distribution, especially in cold regions with high hydroclimatic heterogeneity. We evaluate winter climate changes in the six ecozones (Mountains, Foothills, Prairie, Parkland, Boreal, and Taiga) in Alberta, Canada, and identify regions of elevated susceptibility to change. Evaluation of historic trends and future changes in winter climate use high-resolution (~10 km) gridded data for 1950–2017 and projections for the 2050s (2041–2070) and 2080s (2071–2100) under medium (RCP 4.5) and high (RCP 8.5) emissions scenarios. Results indicate continued declines in winter duration and earlier onset of spring above-freezing temperatures from historic through future periods, with greater changes in Prairie and Mountain ecozones, and extremely short or nonexistent winter durations in future climatologies. Decreases in November–April precipitation and a shift from snow to rain dominate the historic period. Future scenarios suggest winter precipitation increases are expected to predominantly fall as rain. Additionally, shifts in precipitation distributions are likely to lead to historically-rare, high-precipitation extreme events becoming more common. This study increases our understanding of historic trends and projected future change effects on winter snowpack-related climate and can be used inform adaptive water resource management strategies.