Advances in global hydrology–crop modelling to support the UN’s Sustainable Development Goals in South Asia

Achieving the United Nation's Sustainable Development Goals (SDG) in the context of a rapidly changing climate and demographics is one of the major challenges for South Asia. Interventions aimed at achieving the SDGs will be varied and are likely to contain basin-wide trade-offs that need to be understood. In this paper, we synthesize recent global hydrology-crop model developments, with a specific focus on human impact parameterisations like the management of human built storage capacity, irrigation withdrawal and supply, and irrigation efficiency. We show that these models can help improve our understanding of the composition and flows of water, and the linkages between water scarcity and food production. To fully exploit the potential of improved models for policy support and the design of pathways towards SDG achievement, we envisage scope to include more local data from test fields and pilot sites, use the models to derive biophysical and financial feasibility of interventions, and improve the interaction with policy-makers and regional stakeholders through the development of better communication and visualisation tools

Crop-specific seasonal estimates of irrigation-water demand in South Asia

This work was carried out by the Himalayan Adaptation, Water and Resilience (HI-AWARE) consortium under the Collaborative Adaptation Research Initiative in Africa and Asia (CARIAA), with financial support from the UK Government’s Department for International Development and the International Development Research Centre, Ottawa, Canada. We acknowledge the Potsdam Institute for Climate Impact Research for their support in using the LPJmL model and computational facilities.Especially in the Himalayan headwaters of the main rivers in South Asia, shifts in runoff are expected as a result of a rapidly changing climate. In recent years, our insight into these shifts and their impact on water availability has increased. However, a similar detailed understanding of the seasonal pattern in water demand is surprisingly absent.This hampers a proper assessment of water stress and ways to cope and adapt. In this study, the seasonal pattern of irrigation-water demand resulting from the typical practice of multiple cropping in South Asia was accounted for by introducing double cropping with monsoon-dependent planting dates in a hydrology and vegetation model. Crop yields were calibrated to the latest state-level statistics of India, Pakistan, Bangladesh and Nepal. The improvements in seasonal land use and cropping periods lead to lower estimates of irrigation-water demand compared to previous model-based studies, despite the net irrigated area being higher. Crop irrigation-water demand differs sharply between seasons and regions; in Pakistan, winter (rabi) and monsoon summer (kharif) irrigation demands are almost equal, whereas in Bangladesh the rabi demand is 100 times higher. Moreover, the relative importance of irrigation supply versus rain decreases sharply from west to east. Given the size and importance of South Asia improved regional estimates of food production and its irrigation-water demand will also affect global estimates. In models used for global water resources and food-security assessments, processes like multiple cropping and monsoon-dependent planting dates should not be ignored

Going local: evaluating and regionalizing a global hydrological model’s simulation of river flows in a medium-sized East African basin

Study region: The Rufiji basin, East Africa. Study focus: Rapid advances in global hydrological model (GHM) resolution, model features, and in situ and remotely sensed datasets are driving progress towards local relevance and application. Despite their increasing use, however, evaluation of local hydrological performance of GHMs is rare. In this paper, we examine the performance of a well-known GHM (LPJmL, recently modified to ∼9 km resolution) with and without modest steps to regionalise the model. We consider the Rufiji river basin, an economically important medium-size basin in eastern Africa. New hydrological insights for the region: Our results indicate that the unmodified GHM does provide a reasonable first approximation of spatial variability in mean flow conditions, but scores rather poorly on seasonal and inter-annual variability. For the model to achieve levels of performance indicators comparable with bespoke modelling, modifications to model inputs, additional runoff delay and wetland parameterization were required. The largest improvements are associated with adjustments in precipitation and enhanced runoff delay. With the modified version, as a proof of concept, we show that a well-known drying trend in a major tributary of the Rufiji can be explained by implementing irrigation abstractions in the model. Overall, the results suggest that with limited and fairly simple modification GHMs can be regionalised to allow their use for scenario testing and further exploration of key local processes in basins with limited observational data

Ультразвуковое исследование при дегенеративно-дистрофических и воспалительных заболеваниях коленного сустава

Рассмотрены актуальные вопросы диагностики заболеваний коленного сустава − деформирующего остеоартроза, ревматоидного и псориатического артритов. Предложены критерии дифференциальной диагностики этих заболеваний.Urgent issues of diagnosis of knee joint diseases (osteoarthrosis deformans, rheumatoid and psoriatic arthritis) are discussed. The criteria of differential diagnosis are suggested

Selection of climate models for developing representative climate projections for the Hindu Kush Himalayan Region

This series is based on the work of the Himalayan Adaptation, Water and Resilience (HI-AWARE) consortium under the Collaborative Adaptation Research Initiative in Africa and Asia (CARIAA) with financial support from the UK Government’s Department for International Development and the International Development Research Centre, Ottawa, Canada. CARIAA aims to build the resilience of vulnerable populations and their livelihoods in three climate change hot spots in Africa and Asia. The programme supports collaborative research to inform adaptation policy and practice.In HI-AWARE, both statistical and dynamical downscaling techniques will be used to downscale and bias correct climate model data to higher spatial resolutions. For both approaches, General Circulation Models (GCMs) and Regional Climate Models (RCMs) must be selected to either be statistically downscaled or used as boundary and forcing for dynamical downscaling. This report discusses the statistical downscaling component. There are two fundamentally different methods for selecting appropriate GCMs/RCMs. The first approach aims to cover the full envelope of possible futures ranging from dry and cold projections to wet and warm projections, while the second approach selects GCMs/RCMs on the basis of indicators of past performance. Both approaches have their pros and cons, but in the case of the Hindu Kush Himalayas (HKH) the first approach may be preferable as climate models have considerable difficulty in simulating past climate (Turner and Annamalai 2012). In this study, we develop a new method that combines the two existing methods. We aim to select a set of climate models that both cover a wide range of possible futures, but are also able to reproduce the most important processes in the region

Climate change vs. socio-economic development : understanding the future South Asian water gap

The study assesses combined impacts of climate change and socio-economic development on the future water gap in the Indus, Ganges, and Brahmaputra (IGB) river basins until the end of the 21st century. The IGB provides about 900 million people with water resources used for agricultural, domestic, and industrial purposes. Environmental flow requirements (EFRs) have not been considered in most future assessments on climate change induced or socio-economic development-induced changes in water supply and demand in the region. The paper proposes a model simulation incorporating factors of the hydrological cycle.UK Government’s Department for International Developmentcore funds of ICIMODNetherlands Organisation for Scientific Research (NWO

Integration of future water scarcity and electricity supply into prospective LCA: Application to the assessment of water desalination for the steel industry

The urgency of tackling global environmental issues calls for radical technological and behavioral changes. New prospective (or ex ante) methods are needed to assess the impacts of these changes. Prospective life cycle assessment (LCA) can contribute by detailed analysis of environmental consequences. A new stream of research has taken up the challenge to create prospective life cycle inventory (LCI) databases, building on projections of integrated assessment models to describe future changes in technology use and their underlying environmental performance. The present work extends on this by addressing the research question on how to project life cycle impact assessment methods for water scarcity consistent with prospective LCI modeling. Water scarcity characterization factors are projected from 2010–2050 using the AWARE method, based on SSP-RCP scenario results of the integrated assessment model IMAGE. This work is coupled with prospective LCI databases, where electricity datasets are adapted based on the energy component of IMAGE for the same scenario. Based on this, an LCA case study of water desalination for the steel industry in Spain is presented. The resulting regional characterization factors show that some regions (i.e., the Iberian Peninsula) could experience an increase in water scarcity in the future. Results of the case study show how this can lead to trade-offs between climate change and water scarcity impacts and how disregarding such trends could lead to biased assessments. The relevance and limitations are finally discussed, highlighting further research needs, such as the temporalization of the impacts

Quantification of run-of-river hydropower potential in the Upper Indus basin under climate change

IntroductionDespite ambitious plans to quadruple hydropower generation in the Indus basin, a quantitative assessment of the impact of climate change on hydropower availability in the basin is missing. To address this gap, we combine downscaled CMIP6 projections with the Hydropower Potential Exploration (HyPE) model to quantify future hydropower potential available in the upper Indus basin.MethodsHyPE uses a spatial cost-minimization framework to evaluate four classes of hydropower potential, namely theoretical, technical, financial and sustainable, considering various constraints on the siting and sizing of two run-of-river hydropower plant configurations.ResultsUnder future discharge projections, all classes of potential increase while subbasin changes align with the spatial patterns projected in hydro-climatology. Theoretical potential changes by 3.9–56 %, technical potential by −2.3–46.8 %, financial potential by −8.8–50.4 % and sustainable potential by −6.1–49.7 %. A small decline is observed in the northwestern subbasins where increase in potential is lower than in the southeast. In contrast, with increasing variability in the Indian Summer Monsoon in the future, the southeastern subbasins have the strongest increase in sustainable potential accompanied by higher increase in plant size, decrease in costs and higher variability. The southeastern Satluj subbasin is the hotspot where sustainable potential has the highest increase of up to 145 %. The northwestern Kabul subbasin has the highest decrease of up to −27 %. The Swat subbasin has the lowest variability in sustainable potential while the Jhelum and Indus main subbasins remain the subbasins with the cheapest potential into the future. The performance of future sustainable portfolios differ from the performance of historical portfolios by −11.1–39.9 %.DiscussionHence, considering future climate in the present-day planning of hydropower will lead to improved performance under a majority of scenarios. The sufficiency of hydropower potential to fulfill energy security depends on future population growth. Energy availability is projected to decline in the northwest as population increases faster than hydropower potential. The per capita sustainable potential In the Kabul subbasin reduces to a third of the historical value. A socio-hydrological approach is necessary to address the complexity of achieving sustainable and equitable hydropower development in the Indus basin under such spatial mismatch between hydropower availability and energy demand in a resource-limited world

The critical role of the routing scheme in simulating peak river discharge in global hydrological models

Global hydrological models (GHMs) have been applied to assess global flood hazards, but their capacity to capture the timing and amplitude of peak river discharge—which is crucial in flood simulations—has traditionally not been the focus of examination. Here we evaluate to what degree the choice of river routing scheme affects simulations of peak discharge and may help to provide better agreement with observations. To this end we use runoff and discharge simulations of nine GHMs forced by observational climate data (1971–2010) within the ISIMIP2a project. The runoff simulations were used as input for the global river routing model CaMa-Flood. The simulated daily discharge was compared to the discharge generated by each GHM using its native river routing scheme. For each GHM both versions of simulated discharge were compared to monthly and daily discharge observations from 1701 GRDC stations as a benchmark. CaMa-Flood routing shows a general reduction of peak river discharge and a delay of about two to three weeks in its occurrence, likely induced by the buffering capacity of floodplain reservoirs. For a majority of river basins, discharge produced by CaMa-Flood resulted in a better agreement with observations. In particular, maximum daily discharge was adjusted, with a multi-model averaged reduction in bias over about 2/3 of the analysed basin area. The increase in agreement was obtained in both managed and near-natural basins. Overall, this study demonstrates the importance of routing scheme choice in peak discharge simulation, where CaMa-Flood routing accounts for floodplain storage and backwater effects that are not represented in most GHMs. Our study provides important hints that an explicit parameterisation of these processes may be essential in future impact studies

Intercomparison of global river discharge simulations focusing on dam operation --- Part II: Multiple models analysis in two case-study river basins, Missouri-Mississippi and Green-Colorado

We performed a twofold intercomparison of river discharge regulated by dams under multiple meteorological forcings among multiple global hydrological models for a historical period by simulation. Paper II provides an intercomparison of river discharge simulated by five hydrological models under four meteorological forcings. This is the first global multimodel intercomparison study on dam-regulated river flow. Although the simulations were conducted globally, the Missouri-Mississippi and Green-Colorado Rivers were chosen as case-study sites in this study. The hydrological models incorporate generic schemes of dam operation, not specific to a certain dam. We examined river discharge on a longitudinal section of river channels to investigate the effects of dams on simulated discharge, especially at the seasonal time scale. We found that the magnitude of dam regulation differed considerably among the hydrological models. The difference was attributable not only to dam operation schemes but also to the magnitude of simulated river discharge flowing into dams. That is, although a similar algorithm of dam operation schemes was incorporated in different hydrological models, the magnitude of dam regulation substantially differed among the models. Intermodel discrepancies tended to decrease toward the lower reaches of these river basins, which means model dependence is less significant toward lower reaches. These case-study results imply that, intermodel comparisons of river discharge should be made at different locations along the river’s course to critically examine the performance of hydrological models because the performance can vary with the locations