S4

Many countries vulnerable to climate change do not yet have national modelling systems in place to guide adaptation measures. Especially low- and middle-income countries are at the mercy of global or large-scale estimates of climate change impacts, which might not be relevant to the spatial scale of societal challenges or to engineering methods based on observations.

Climate services are launched with scientific data, which can be misunderstood and misused if not communicated in a pedagogic way. For instance, the results from climate models represents an average for a calculation unit and neglects the spatial variability within that unit. In-situ observations from monitoring stations represents a point value and may thus be very different from areal estimates. Moreover, observations are relatively few leaving large areas ungauged. Sometimes, the area of interest falls in between grids or is very small compared to the grid or catchment and the average values may then not be representative or useful.

Moreover, the results from climate models represents a statistical period of 30 years, but not the chronological happening of events or weather conditions. Time-series from climate models are thus not representing specific dates and should not be compared to observed time-series but only to statistical estimates, such as indicators. 

In this presentation we showcase (1) state-of the art methods to produce climate indicators for weather and water data over large domains, and (2) some ways to tailor climate and water data for local applications and practical use.

We will demonstrate the global climate service climateinformation.org, in which climate and water indicators result from an extensive production chain, merging data from various sources with different resolution in time and space.

For water indicators, climateinformation.org uses results from a global integrated-catchment model, the world-wide HYPE. To tailor data, it is recommended to use a more detailed national/local model or set-up the HYPE model using national/local data. SMHI share the open source HYPE-model code and here we will explain how to apply climate indicators to calculate climate-change effects on water resources using a local/national model. Showcases are given for St Lucia, DR Congo, Cape Verde, and Cambodia.

How to cite: Arheimer, B., Gyllensvärd, F., Capell, R., and Andersson, J.: Tailoring large-scale hydrological models for national planning of climate actions in vulnerable countries, IAHS-AISH Scientific Assembly 2022, Montpellier, France, 29 May–3 Jun 2022, IAHS2022-426, https://doi.org/10.5194/iahs2022-426, 2022.

Data assimilation is a powerful tool that has been used to correct states and parameters of rainfall-runoff models based on recent streamflow, remotely sensed soil moisture or groundwater data. Data assimilation is now routinely applied by forecasting centres around the world to improve simulations and increase forecast skill. In this work, we are less concerned with the direct benefits of data assimilation on model outputs, but more on the nature of the corrections introduced and how they can be analysed to diagnose structural deficiencies in rainfall-runoff models.

Rainfall-runoff models have been shown to lack extrapolation capacity in simulating dry and wet periods that are more extreme than calibration conditions. This is particularly concerning in the context of climate change studies where more climate extremes are generally predicted for expected. This is the case in South-Eastern Australia where annual rainfall is expected to decrease significantly under most climate scenarios. Consequently, the improvement of rainfall-runoff model structures to better simulate dry flow regimes is critical to obtain robust estimates of water resources availability.

In this work, we assimilated streamflow data in the GR2M monthly rainfall-runoff models for 100 catchments in South-East Australia. The assimilation was conducted during a wet period between 1970 to 1995 and used to identify model structure deficiencies, particularly in the function computing water exchanges with nearby catchments. An attempt of correcting these deficiencies was undertaken using a simple regression approach. Finally, the correction was applied during a dry period (1995-2010) and performance was compared with the original (uncorrected) model. The results suggest that the corrected simulations better capture streamflow extremes, especially low flows. Further work is also discussed related to the use of additional data such as LAI and groundwater data to better constrain the correction regression.

How to cite: Lerat, J., Chiew, F., Zheng, H., and Robertson, D.: Use of data assimilation to improve rainfall-runoff model structure for climate change projections, IAHS-AISH Scientific Assembly 2022, Montpellier, France, 29 May–3 Jun 2022, IAHS2022-365, https://doi.org/10.5194/iahs2022-365, 2022.

The program NEXUS Gains addresses key challenges of transforming water, energy, food and ecosystem (WEFE) systems in transboundary bread-basket basins in East and Southern Africa (Blue Nile and Limpopo basins), Central (Aral Sea basin) and South Asia (Ganges and Indus basin) in a changing world. The program particularly explores water resource management options to understand WEFE system interdependencies, trade-offs and synergies and develop more sustainable development pathways for all members society.

The presentation will discuss alternative interventions to increase water productivity different sectors (irrigation, forestry, industries) across scales ranging from farm to watershed to river basin scales. Therefore, particular attention will be given to integrated water storage management in human built and natural infrastructure in South Asia and East Africa. The implications for hydrological process and water resources dynamics and wider environmental, social and economic systems are analyzed and related policy implications are discussed considering also climate change.

How to cite: Uhlenbrook, S., Ringler, C., Lautze, J., McCartney, M., and Hafeez, M.: On the role of water resources management to transform water, energy, food and ecosystem (WEFE) systems in transboundary river basins, IAHS-AISH Scientific Assembly 2022, Montpellier, France, 29 May–3 Jun 2022, IAHS2022-463, https://doi.org/10.5194/iahs2022-463, 2022.

Enhanced coordination is an important feature of the water–energy–food (WEF) nexus – an agenda that highlights the interdependencies between these sectors. But, while greater coordination is often promoted as a goal, particularly in relation to policy and planning, achieving it is far from easy. There are two complementary dimensions to understanding the WEF nexus; quantifying the physical links between sectors, and unravelling the management and governance structures involved. This paper profiles two different approaches to address the former dimension as a means to enable greater understanding of multi-sector interdependencies. One uses a multi-scale analysis of nexus linkages in the Gulf region to show how integrating new datasets can allow a more comprehensive analysis of WEF interdependencies, and in so doing highlight emerging areas of risk. The other illustrates how application of visualisation methods in a river basin can help present to stakeholders the complex trade-offs that exist across the WEF nexus and potentially contribute to decision-making. This study sought guidance on what stakeholders felt were important services that development in their river basin should achieve sustainably (performance indicators) and then simulated many thousands of combinations of options to identify which ones worked best across the different performance indicators using multi-objective optimisation. Respectively, these examples show how a nexus approach can reveal that a country’s food imports are associated with unsustainable agricultural practices and where the use of innovative modelling and visualisation techniques can provide opportunities to convey the complex outcomes of decisions, capturing alternative perspectives and values. So - while coordination is hard to achieve - new datasets and innovative methods of visualisation offer promise in addressing at least some of the barriers that confront progress in moving forward a nexus agenda.

How to cite: Conway, D.: Progress in characterising water-energy-food interdependencies, IAHS-AISH Scientific Assembly 2022, Montpellier, France, 29 May–3 Jun 2022, IAHS2022-360, https://doi.org/10.5194/iahs2022-360, 2022.

Abstract

Conflict over water resources emerges from complex interactions among biophysical, social, and economic processes operating at multiple scales. The concomitant use of surface and groundwater managed for multiple uses is a classic coping strategy to manage the water scarcity yet a relevant example of such conflict. Managing these resources is thus a dynamic decision-making process involving actors with different perceptions of the situation, who adapt different strategies to satisfy their objectives and interests. This paper presents the results of an effort to address these conflicts through reinforcing the adaptive capacity of different actors to cope with water scarcity in a multi-scale irrigation system. The study site focuses on the irrigated area of Zaouiet Jedidi in Northeast Tunisia. This region is characterized by an intensive irrigated agriculture, mostly through an excessive pumping of groundwater resources. Individual strategies to face the water scarcity are dominating leading to a rapid deterioration of the groundwater resources. Irrigation through individual and informal wells is an example of such strategies. As the demand for agricultural and urban water has concurrently continued to develop, the groundwater has continued to drop. Despite the State’s efforts to increase the water supply to the region through the transfer of surface water from the dams of northwestern Tunisia, the overexploitation of groundwater resources exceeded 200%. A participatory process was implemented to initiate a process of interaction and coordination between the different stakeholders involved in the management of the irrigated area. We analyzed to what extent and by what mechanisms, a participatory problem-solving process can facilitate the emergence of collection action to face the water scarcity.

How to cite: Ferchichi, I., Zairi, A., and Marlet, S.: Water scarcity conflicts: Supporting dialogue and negotiation, IAHS-AISH Scientific Assembly 2022, Montpellier, France, 29 May–3 Jun 2022, IAHS2022-425, https://doi.org/10.5194/iahs2022-425, 2022.

The concept of sustainability in water management remains an amorphous notion. Despite its widespread use, there is not a shared and accepted definition of the concept of sustainability in water management, including its monitoring and assessment, particularly at river basin scale. Sustainability Assessment (SA) can be defined as any process that aims at planning and direct decision-making toward sustainable development. An interdisciplinary approach for understanding, measuring and monitoring sustainability of water management practices includes the holistic development of Indicator-Based Assessment (IBA) frameworks as policy/decision support tools. The IBA refers to the positive, negative, and neutral qualifications of an indicator based on the comparison between its observed evolution (and/or status), and the desired evolution set for the indicator by means of a frame of reference. Therefore, developing IBA frameworks help to synthesize information and monitor changes in water management systems.

Recently, developing indicator-based assessment frameworks and constructing indexes have evolved significantly toward monitoring the United Nations Sustainable Development Goals (UN SDGs). However, there are limited studies on developing sustainability indexes or indicator-based sustainability assessment frameworks at the river basin scale for complex issues of water management. The aim of this work is to provide a review of i) the concept of SA in water management and also ii) the methodology of indicator-based framework development. Finally, a case study of developing an indicator-based sustainability assessment framework is presented for the Mashhad River basin in Iran.

How to cite: Shafiei, M., Gharari, S., Gharesifard, M., Ghoreishi, M., and V. Castro, C.: Sustainability Assessment: The role of Indicator-based Frameworks in Sustainable Water Management, IAHS-AISH Scientific Assembly 2022, Montpellier, France, 29 May–3 Jun 2022, IAHS2022-271, https://doi.org/10.5194/iahs2022-271, 2022.

Warming climate is altering streamflow characteristics and posing pressure on water systems. Here, the impacts of climate change on a headwater system in Alberta, Canada, is evaluated, with the primary goal of understanding the role of hydrological system representation. For this purpose, a conceptual hydrological model, i.e., HBV-MTL, is coupled with two snowmelt estimation modules, i.e., Degree-Day and CemaNeige. The models are calibrated using point- and grid-based climatic data and considering lumped and semi-distributed representation of the basin and are linked to a water allocation model to simulate reservoir dynamics and downstream water deliveries. The bias-corrected outputs of 19 climate models during 2021-2099 are then used to estimate the future water system conditions. Results show that during the historical period, all models provide acceptable performance, with minor distinctions; however, their simulations highly divergence in the future period. The models unanimously project significant water deficit in meeting agricultural water demands and flood risk in the future. However, the quantified vulnerabilities depend on the considered hydrological models, among the utilized snow routine module highly influences estimated natural and regulated flow values. It is suggested to consider these projections and revise the Oldman reservoir water allocation plans to mitigate climate change's adverse impacts on this water system.

How to cite: Hassanzadeh, E. and Sharifinejad, A.: Evaluating the impact of climate change on water system vulnerabilities using multiple hydrological models, IAHS-AISH Scientific Assembly 2022, Montpellier, France, 29 May–3 Jun 2022, IAHS2022-234, https://doi.org/10.5194/iahs2022-234, 2022.

Rainwater harvesting systems (RHS) has been a relevant alternative of water supply in urban areas facing increasing water demand associated to limited water availability. However, previous work has showed that the performance of these systems is highly affected by climate data such as precipitation (well characterized uncertainties). The present study aims to assess the impact of system parameters (water demand, tariffs, storage volume, collect area) named here as deep uncertainties factors influence the feasibility of RHS. So, performance criteria were defined such as Percentage of Satisfied Demand - PSD, Reliability - REL, Percentage of Rainwater Harvesting - PRH, Net Present Value - NPV, Net Present Value Volume - NPV and Benefit Cost Rate - BCR for different scenarios that incorporate uncertainties in precipitation regime, water tariff, discount rate and increase of operating costs rate. The simulation of the RHS performance considered eight categories of residential buildings according to representative water consumption (ranging from 4.748 to 44.673 m³/month) and two characteristic catchment areas for each of the four group of demands (ranging from 60 to 400 m²) in the city of Rio Verde located in the central of Brazil. An ensemble of 1000 scenarios was defined using the Latin Hipercube Sampling (LHS) method and booststrapping resampling (in the case of precipitation). Then, it was evaluated how different scenarios affected each indicator and if uncertainties from some of the parameters have a greater impact on the performance criteria. Results showed low influence of precipitation scenarios on the performance criteria, maybe due to the sampling method that did not generate significant variability. For the elements with deep uncertainty, the relationship among the water tariff and the discount rate readjustments with NPV was confirmed. Thus, the importance of evaluating these elements carefully to achieve rainwater harvesting systems projected performance was confirmed.

How to cite: Ribeiro Pacheco, G. C. and Albuquerque Alves, C. D. M.: The performance of rainwater harvesting systems in the context of deep uncertainties, IAHS-AISH Scientific Assembly 2022, Montpellier, France, 29 May–3 Jun 2022, IAHS2022-283, https://doi.org/10.5194/iahs2022-283, 2022.

Nature-based solutions (NBSs) use earthen materials to mimic natural stormwater flow by increasing levels of greenspace within the built environment. Research has demonstrated the capability of NBSs to address overlapping issues of societal well-being, including improvements in mental and physical health, social vulnerability, sense of well-being, and socio-economics. However, existing NBS planning frameworks emphasize hydro-environmental modeling and cost-benefit analysis for regional spatial allocation. Social conditions are only incorporated at preliminary planning stages through visualization of geospatial hotspots and are not embedded directly within the optimization model. By relying on metrics of hydro-environmental mitigation, the unique spatial exposures of social deprivation that could benefit from NBSs are not well-captured. Water dynamics and social well-being are highly entangled, and we necessitate improved methods for combining hydrological and social characteristics in a robust manner. Here, a novel framework is proposed and demonstrated that integrates hydro-environmental modeling, economic efficiency, and social deprivation using a dimensionless Gini coefficient. Hydro-environmental risk and social disparity are combined within a common measurement unit to capture variation across spatial domains and to optimize fair distribution across the study area. Advances in neighborhood-scale datasets for measuring social deprivation are leveraged to improve fundamental, multi-objective planning in human-water systems. A case study in the White Oak Bayou watershed in Houston, Texas, USA is used to demonstrate how the optimal spatial allocation of NBSs is location-dependent with varying tradeoffs amidst overlapping goals (e.g., stormwater runoff mitigation, water quality abatement, economic efficiency, and equity-based allocation). The composite Gini coefficient demonstrates how water resources planning may be addressed as a holistic system of human-water phenomena to minimize tradeoffs across disparate domains while improving social justice.

How to cite: Vail Castro, C.: Water resources management as a coupled hydro-environmental and social-equity-based optimization framework, IAHS-AISH Scientific Assembly 2022, Montpellier, France, 29 May–3 Jun 2022, IAHS2022-257, https://doi.org/10.5194/iahs2022-257, 2022.

Maintaining ecological flow is a need for enviromental  sustainability of regulated rivers  in managed  water bodies, whatever the different and competitive water demands (urban supply, irrigation, energy, or ecology). This is a challenge that the hydropower sector has to deal with, in areas subjected to complex meteorology with long drought periods followed by intense flood episodes, like those affected by the Mediterranean climate, specially in run of river facilities. These facts point towards the introduction of new regulatory frameworks to push towards a minimum river flow regime more adapted to the naturally variable hydrological regime of streamflow in Mediterranean regions. This question is not trivial and this challenge becomes even more critical in a climate change scenario in which hydropower energy is markedly affected not only by the market but also  by a priori more extreme meteorological events. In this paper, the compliance of the minimum river flow regime established by the Water Authorities in ten water bodies with hydropower generation (6 run-of-river plants and 4 reservoir plants) in southern Spain has been analyzed using historical streamflow and reservoir inflow data series, respectively and assuming that these values  closely represent the natural regime upstream the hydropower plans. For each case, the compliance of ecological regime thresholds during the last 10 hydrological years (September 2010 - August 2020) was analyzed at daily scale. In addition,  an hourly scale analysis was added when hourly data series were available. The results obtained showed that the natural regime of the watercourses hardly complies with the conditions established in the state law on compliance with ecological flows in all of the cases, and that, therefore, these flows were oversized. This overestimation is extremely unbalanced in some of the bodies studied, as in the case of the Cala reservoir, where even a reduction of 90% of the ecological flow, cannot be met by one of the 4 conditions on more than 60% of occasions.

The results highlight the needs for a balanced and updated environmental flow regime in regions with large natural variability in order to support the sustainability of hidropower, especially in run of river facilities.

How to cite: Aparicio, J., Contreras, E., Aguilar, C., Moreno, F., and Polo, M. J.: Are the thresholds of ecological flows established by the water management authorities aligneed with the natural regime of rivers in Mediterranean regions?, IAHS-AISH Scientific Assembly 2022, Montpellier, France, 29 May–3 Jun 2022, IAHS2022-676, https://doi.org/10.5194/iahs2022-676, 2022.

Abstract

The construction of dams and reservoirs for hydropower generation has been increasing in major river basins around the world. These dams store huge amounts of water thereby reducing the streamflow in the low-lying regions. Such changed seasonality of streamflow has various socio-economic and environmental consequences. Downstream dwellers are left with reduced water for their daily lives, irrigation, fisheries, and ecological services, resulting in conflicts. This paper aims to study the benefit loss of downstream communities caused by the operation of a huge reservoir in the upstream area for hydropower purposes. The benefits are calculated in terms of economic benefit through hydropower, irrigation, fisheries in both upstream and downstream communities through simulation of socio-hydraulic changes after the reservoir operation. The study area is located in Nam Ngum River Basin, a tributary of the Mekong River in Lao People's Democratic Republic (PDR). The Nam Ngum 1 Reservoir and its downstream region, which includes the capital city “Vientiane Capital” will be studied. Nam Ngum 1 Reservoir is the largest and oldest reservoir of Lao PDR storing about 8.5 billion m³ of water. The methodology includes 2 operations: reservoir operations and economic benefit calculations. The results obtained from the simulation will certainly help to address the economic problems associated with an uneven share of water and will help in the further investigation and adoption of integrated water resource management in other regional, national or transboundary scales as well.

Keywords: dam operation model, integrated water resource management, benefit loss, reservoir operations

How to cite: Lamichhane, A. and Noda, K.: Dam operation Model as a part of Integrated Water Resource Management in Nam Ngum River Basin, Lao PDR, IAHS-AISH Scientific Assembly 2022, Montpellier, France, 29 May–3 Jun 2022, IAHS2022-612, https://doi.org/10.5194/iahs2022-612, 2022.

Climate warming and evolution water demand for anthropogenic activities are two related ongoing changes that may increase existing pressure on water resources. Adaptation strategies are usually thought on the basis of hydrological projections. These projections, however, rarely incorporate changes in water and land management, issues that are then addressed by the adaptation plans within a sequential process. The objective of this study is to develop a modelling framework that incorporates water and land management evolution within a spatially distributed hydrological model in order to produce projections that are more realistic on the water resources shortages. We applied this methodology on the Moselle River (North-East France) basin using climate projections derived from various representative concentration pathway scenarios (RCPs), general circulation models (GCM), and regional climate models (RCM) in a multi-scenario multi-model approach. Hydrological projections are computed from a conceptual hydrological model, and a recent R package (airGRiwrm) was used to account for anthropogenic water withdrawals. Through contrasting scenarios of water use evolution built in partnership with the water stakeholders, we are able to explore different evolutions of water demand for each type of use present in the Moselle basin (withdrawals for domestic and industrial uses, energy production, and waterway navigation). These scenarios allow us to feed the hydrological model with different water withdrawals, in addition to the climate scenarios. The results of this multi-scenario and multi-model impact study on the water resources will be used to evaluate the water management sustainability and the adaptation levers.

How to cite: Lemaitre-Basset, T., Thirel, G., and Oudin, L.: Modelling long-term effects of climate change and anthropogenic activities on water resources of the Moselle River basin. , IAHS-AISH Scientific Assembly 2022, Montpellier, France, 29 May–3 Jun 2022, IAHS2022-158, https://doi.org/10.5194/iahs2022-158, 2022.

Many canals were built during the 19th century to satisfy multiple uses. The priorities among them reflected the societal needs of the time: navigation, drinking water, irrigation, hydroelectricity, minimum flow in rivers for sanitation goals, etc. Today, multiple changes affect these priorities: the decline of available resources makes it difficult to satisfy all uses. In addition to climate change, these water infrastructures are subject to controversies as a result of changes in agriculture and irrigation, claims for minimum flows for aquatic ecosystems, the urban sprawl, and the need for hydropower. Everything is questioned: the hydraulic management and indicators, the economic model for recovering the sustainable cost, the social contract that defines priority uses, and the fair distribution of powers and duties between the stakeholders. To summarize, the role of these old canals in global change adaptation strategies is being questioned, as dam projects. Our hypothesis is that these old hydraulic works can help the territories to adapt, if reforms of their hydraulic, economic and institutional management are carried out at the same time.

The recent history of the Neste Canal illustrates this complex ongoing transformation. Since 1962, it has diverted yearly 220 Mm³ from the Neste River, a tributary of the Garonne River in the foothills of the French Pyrenees, to supply 17 rivers in Gascony. Artificial lakes have progressively filled out this complex interconnected hydraulic system. This "Neste system" covers a territory of 8,400 km², irrigates about 60,000 ha, and supplies 350,000 inhabitants with drinking water (see map). In this paper, we describe the evolution of the multiple uses as well as the decrease in the flows derived over the last 70 years, and then the structural imbalance of its economic model. Its future depends on i) the political recognition of its contribution to the minimum water flows of the rivers of Gascony, ii) the introduction of a payment for this ecological function, and iii) changes in hydraulic regulation system to satisfy this last function previously managed as a hydraulic constraint.

How to cite: Garin, P., Montginoul, M., Lepercq, D., and Chisne, P.: Technical, economic and social rehabilitation of old canals to cope with global change: the case of the Neste Canal (France), IAHS-AISH Scientific Assembly 2022, Montpellier, France, 29 May–3 Jun 2022, IAHS2022-563, https://doi.org/10.5194/iahs2022-563, 2022.

The Seine catchment (located in the North of France) includes a system of four large reservoirs to protect against floods and water shortages multiple locations downstream including the Paris region. For each downstream key location, the reservoirs try to keep the streamflow between minimum and maximum thresholds, which are all objectives to be achieved. We propose here a framework assessing the risk of failing to meet each of these objectives under specific hydroclimatic conditions considering the current filling state of each reservoir and the calendar day.

First, a semi-distributed hydrological model of the basin calibrated on influenced flows over the period 1959-2019 is used to simulate naturalised flows for a given climatic daily time series. Then, for each objective, a dynamic programming optimisation provides optimal filling curves that are statistically analysed to produce yearly probabilistic upper (for floods) or lower (for droughts) filling curves. These results are highlighted by an interactive graphical user interface based on an R Shiny application showing the risk probability of future failure of each objective depending on the calendar day and the storage state of each reservoir.

This assessment is conducted with historical climatic observations as well as a set of the recent French DRIAS 2020 climatic projections for different future periods: 2021-2050, 2041-2070 and 2071-2100.

How to cite: Dorchies, D., Bader, J.-C., Nunez Torres, L., Delaigue, O., and Thirel, G.: Drought and flood risk assessment of the Seine basin reservoir management under climate change, IAHS-AISH Scientific Assembly 2022, Montpellier, France, 29 May–3 Jun 2022, IAHS2022-105, https://doi.org/10.5194/iahs2022-105, 2022.

In Colombia, around 70% of the energy is from hydropower source and most of its associated hydraulic infrastructure is located in the macro-basin of the Magdalena and Cauca rivers. These projects are generating a drainage network fragmentation and a substantial alteration in natural regimes of both flow and sediment, which is having negative impacts on freshwater ecosystems and their ecosystem services. Nowadays, there is a methodology related to environmental flows, proposed in 2018 by the Colombian Ministry of Environmental and Sustainable Development (not adopted as a regulation), which integrates two sets of stakeholders: environmental authorities for integrated water resources management at regional scale and holders of new projects with high impact on the natural flow regime of rivers. Since it is only a non-binding methodological proposal, there are no known practical applications to evaluate its effectiveness in terms of reduction of environmental impacts, social conflicts, and water governance. In this sense, we propose a step forward in the analysis of the effects of its application in rivers with available hydrological data and under natural regime conditions through a taylor-made computer model (HeCCA 1.0) which is composed of the most important methods contemplated in the above-mentioned methodology.

HeCCA 1.0 allows determining the percentage of monthly use of a river without compromising its ecosystem function, based on it, river discharge data of 15 different watersheds located throughout the entire country were used. In this test, a range of drainage areas (180 to 73000 km²) was covered located between 25 and 2993 meters above sea level. The systems belong to different seasonal behaviors depending on the geographical location (monomodal or bimodal). For the monomodal regime, utilization percentages were obtained between the 61%8 and 77%29; and for bimodal regimen between 14% and 49%32.

These results depend on the geographical location of the basin, the watershed size, if it is related to the runoff seasonality along the year in the different catchment areas of the country. The taylor-made computer model provides stakeholders a holistic overview of the water availability and management, giving quantitative tools for an optimal development of water governance in the region.

How to cite: Cortés-Torres, N., Fernandez Berbeo, M. C., Vega Idarraga, J. D., Ramos Romero, V., Pulgarin, C. A., Perez Pedraza, M., Rodríguez Vega, N. D., Yanala Bravo, J. C., Alarcón, A., Lopez Bayona, A., Ortega Tenjo, K. J., Molano, J. M., Cubillos Peña, C., and Salazar-Galán, S.: Environmental flows and integrated water resources management in Colombia, IAHS-AISH Scientific Assembly 2022, Montpellier, France, 29 May–3 Jun 2022, IAHS2022-418, https://doi.org/10.5194/iahs2022-418, 2022.

Integrated water resource management is paramount in this existing scenario, where population growth along with climate and land-use change become obstreperous. The huge turbulence of rainfall pattern in recent decades, give chances for contrast climate extremities like pluvial floods and droughts along with water scarcity more often. The present study focuses on the southern hydrological basins of Chennai in India, which are Adyar and Kovalam (Ad-Ko) basins. The study area experienced floods in 2015 and 2021 recently, in which almost 75% of 1400 mm (average annual rainfall) poured in a single month. Discrepantly, in 2019, a severe drought, which almost created day zero by completely draining all the water bodies due to inappropriate water management. The Ad-Ko basin comprises 1650 Km², among which, 11% are water bodies. This 11% is further distributed as abandoned quarries, lined canals, reservoirs, tanks, rivers, streams and wetlands. So, the inference is that the Ad-Ko basin already has sufficient natural and man-made water storage and draining facilities. But, it got affected due to a lack of people’s awareness leads to encroachment and improper water management. Though extremities due to climate change are inevitable, several interventions on water management can improve the subsisting condition. MIKE software was chosen to assess and evaluate the benefits of stream diversions and deepening of water bodies, which were incorporated based on the topography. The resulting water balance is optimistic in handling extreme situations. Moreover, the water samples were collected and assessed for their physicochemical properties from various water bodies that could be intervened, periodically between 2019 and 2021. The analysis was carried out based on the American public health association (APHA) and compared with the Bureau of Indian Standards (BIS), World health organization (WHO) limits and found to be suitable for water managing measures. Thus the peer concentration on water management by a highly aware urban population can reduce the impact of severe climate extremities and improve the socio-economy and environment of the community substantially. 

How to cite: Mariappan, R. K. and Lakshmanan, E.: Assessing the significance of Water resource management in improving the socio-economic and environmental status of a fast-growing urban community: A case study from Southern India, IAHS-AISH Scientific Assembly 2022, Montpellier, France, 29 May–3 Jun 2022, IAHS2022-696, https://doi.org/10.5194/iahs2022-696, 2022.

The development of water quantity assessment focusing on water balances have been identified as a main tool for guiding water policy and management at different decision-making levels. Water Balance Assessment (WBA) accounts for all water fluxes in a watershed by balancing the difference between water inputs and outputs, as well as changes in the watershed water storage. The natural hydrological cycle has been considerably changed due to the substantial anthropogenic activities, which lead to more complexity and therefore uncertainty in estimation and implementation of WBA results. In Iran, the WBA is being conducted every five-year for 609 watersheds, covering the whole country. Although the water authorities are provided with different guidelines and frameworks to improve the WBA, yet there are many multifaceted obstacles in carrying out proper WBA and implementing its results in water management. A preliminary survey showed that most of the barriers are related to the complexity of the human-hydrological watershed systems and the associated uncertainty to the water balance components especially at semi-arid watersheds. Additionally, the complexities associated with institutional arrangements including: access to data, centralized process of conducting WBA, workflow of the WBA projects, diverse stakeholders and their disagreement with WBA final results are among the barriers against smooth WBA in Iran.

In order to understand, identify and provide practical solutions for WBA problems, a national initiative is established with engaging government organizations, universities, NGOs, and research institutes. Therefore, we introduced a collaborative framework entitled “Unsolved Problems in Water Balance (UPWB)” to understand the problems together, co-create capacities and synergize among all stakeholders to solve the WBA problems in Iran. UPWB also covers 11 out of 23 of the IAHS Unsolved Problems in Hydrology (UPH). The UPWB considers three main themes for prioritizing the UPWB in Iran: 1) Technical and computational 2) Institutional and 3) data and information. So far, 10 online webinars by involvement of 400 experts are organized and 46 filled questioners also collected through the Web platform (upwb.ir). Preliminary results confirmed that WBA is the core element of sustainable water management especially in semi-arid regions with various technical, social and institutional aspects.

How to cite: Shafiei, M., Zahraie, B., Soleimaniha, S., Dehbandi, N., Naseri, M., Dehghanisanij, H., Noury, M., Golkar, E., and Ghasemzadeh, F.: Water Balance Assessment in Iran: From Unsolved Problems to Practical Solutions, IAHS-AISH Scientific Assembly 2022, Montpellier, France, 29 May–3 Jun 2022, IAHS2022-170, https://doi.org/10.5194/iahs2022-170, 2022.

Water is the most vital resource on Earth, sustaining all life forms, and it is also the most threatened by climate change and anthropogenic activities. This situation is even more urgent in water-scarce regions like the Middle East and North Africa (MENA) due to water scarcity and increasing demands. Managing these water resources sustainability requires accurate information on water availability and utilization.

Water Accounting is the systematic acquisition, analysis, and communication of information relating to water stocks and fluxes in natural, disturbed, or heavily engineered environments (FAO, 2016). It helps decision-makers understand problems in river basins, identify their drivers, quantify water availability, form proper decisions, and monitor their results over time. Water Accounting Plus (WA+) utilizes open-access spatial data for the analyses, allowing visualizing spatial and temporal trends and patterns. While analyses tools are being refined and made accessible for all, it has not been fully adopted in the MENA, and its implementation is limited to one-off studies.

This paper explores the type of information used/ needed by decision-makers to address the most pertinent water problems in the MENA region through a focused literature review. This was contrasted by the information provided by WA+. Because water problems are context-specific, a more detailed analysis was done for Jordan using semi-structured interviews with key stakeholders.

The results show that the most used information for the assessments in the region is precipitation, river discharge, surface and groundwater stocks at a monthly time scale. However, other aspects such as actual water consumption and losses are essential but not readily available and are therefore estimated using many assumptions. The WA+ framework, by utilizing spatial and temporal RS-based information, can support a systematic quantification of water consumption and losses and helps fill such information gaps. However, supporting decision-making requires more, from assessing the impact of climate change to informing proper water management decisions. Therefore, it is critical to underpin WA+ with scientifically sound hydrological models that can simulate future water fluxes and stocks and test different management interventions using scenario analysis.

How to cite: Amdar, N., Mul, M., Uhlenbrook, S., Rutten, M., Al-Bakri, J., and Jewitt, G.: Relevance of Water Accounting Plus in the MENA region: A pragmatic analysis in light of the region’s challenges to sustainable water management, IAHS-AISH Scientific Assembly 2022, Montpellier, France, 29 May–3 Jun 2022, IAHS2022-588, https://doi.org/10.5194/iahs2022-588, 2022.

West Africa is one of the regions of the globe that is expected to face massive global changes in the coming decades due to sustain population growth rates and climate change. Pressures exerted on water resources are likely to rise as water demands will increase to meet the water, food and energy demands from an ever-increasing, mostly urban, population, while supplies dwindle.

The Senegal River basin is a mostly underdeveloped river basin with a significant hydroelectric and agricultural potential. Policy makers are facing a challenging decision-making problem to identify climate-relevant investments because: (i) the strong divergence of the climate models and the associated uncertainties about future water availability, (ii) conflicting visions regarding the future of the basin: the first emphasizes modern uses such as energy production and irrigated agriculture; the second focuses on traditional uses such as flood recession agriculture and fisheries.

We propose a modeling framework to assess trade-offs and vulnerabilities to both climate and policy factors. First, we generate 1210 GCM-based hydrologic projections for the Senegal River basin from the CORDEX-Africa ensemble and the GR2M hydrological model. The projections are then clustered based on their hydrologic properties, using hydrologic attributes describing the flow regime of the Senegal River. For each cluster, the projection closest to the centroid is selected as the representative one. The next step involves the construction of alternative development and management scenarios of the river basin for the horizons 2050 and 2080. The development scenarios essentially assume different sets of dams and irrigation schemes. Management scenarios, on the other hand, assumed different priorities attached to the operating objectives (water uses).

For each triple projection-development-management scenarios, a stochastic hydroeconomic model determines the optimal operating policies, which are then used in simulation over all GCM-based hydrologic projections belonging to the same cluster. The analysis of simulation results reveals three categories of water uses: (i) high climate-sensitive sectors (hydropower production and navigation), (ii) high allocation policy sensitive sectors (flood recession agriculture and fisheries), and (iii) fairly robust sectors (irrigated agriculture).

How to cite: Guilpart, É., Tilmant, A., Bourgault, M.-A., and Roy, R.: Assessing trade-offs and vulnerabilities to global changes in the Senegal River basin., IAHS-AISH Scientific Assembly 2022, Montpellier, France, 29 May–3 Jun 2022, IAHS2022-371, https://doi.org/10.5194/iahs2022-371, 2022.

The construction of the Akosombo dam in the Lower Volta River basin in Ghana led to the formation of the largest artificial lake by surface area and the resettlement of 80,000 people. As a consequence, the riverine ecosystem changed, as did the lives of the downstream communities who lost their traditional livelihoods. These costs are in contrast to the vast economic benefits that Ghana as a whole has enjoyed from the affordable hydropower, irrigation schemes and lake tourism that have developed after construction of the dam. The Akosombo dam is credited for powering Ghana’s industrialization and making it one of the more developed countries in West Africa. Herein lies the crux of the matter: there are trade-offs between anthropogenic water demands and water for ecosystems which provide important ecosystem services, particularly for riverine communities. A transparent and justifiable approach to dam operation is needed to manage these trade-offs between multiple water users. In this study, Evolutionary Multi-Objective Direct Policy Search (EMODPS) is used to identify the multi-sectorial trade-offs in the Lower Volta River Basin. A designer environmental flow is incorporated as an objective rather than as a constraint and additionally, different policy framings as well as future scenarios encompassing climate change and varying energy futures are investigated. This study not only highlights the challenges faced by dam operators in balancing anthropogenic water demands and environmental considerations, but also identifies opportunities for compromises in the Lower Volta River.

How to cite: Owusu, A., Zatarain Salazar, J., Mul, M., van der Zaag, P., and Slinger, J.: The trade-offs in re-operating dams for the environment in the Lower Volta River Basin, IAHS-AISH Scientific Assembly 2022, Montpellier, France, 29 May–3 Jun 2022, IAHS2022-30, https://doi.org/10.5194/iahs2022-30, 2022.

As if a tower to supply water downstream, the change pattern of water yield of the head water of the Yellow River has drawn high attention of all societal sectors, but not very clear due to the tangling influences by many factors.   Based on the multi-sources of vegetation, hydro-meteorological information, the Vegetation Interface Processes eco-hydrological dynamic model is used to investigate the evolving processes of eco-hydrological elements in the Yellow River basin upon Tangnaihai gauge from 2000 to 2019.  Results showed that the catchment is facing a warming and wetting climate in past two decades, the vegetation growing condition improved quite a lot with the growing period extending for more than 10 days. There has been more glaciers melting in summer and lakes water extension, along with gently increasing of soil moisture. Water yield capacity in the basin has decreased, especially in autumn. Vegetation evapotranspiration (ET) and gross primary productivity (GPP) showed significant synergetic relationship with co-variation. Both ET and GPP exhibited significant increase, in which the top rates occurred in the altitude between 3000 to 4000 m. Water use efficiency (WUE) is enhancing. Attribute analysis showed that the increasing precipitation, vapor pressure deficit and solar radiation were the dominated factors to intensify water-vapor exchange between land surface and atmosphere. Obviously, the warm-wet tendency of climate in the basin apparently improved the ecological environment. However, the increased ecological water consumption resulting in decreased capacity of water yield which impacts adversely the blue water supply, particularly under future climate change.  Trade-off policy action is needed with the aid of elucidating the evolving mechanisms of hydrological and vegetation dynamics to provide scientific basis to maintain the ecosystem sustainability and functioning.

How to cite: Mo, X. and Liu, S.: Co-evolving mechanisms of climate - vegetation - hydrology in the source region of Yellow River, IAHS-AISH Scientific Assembly 2022, Montpellier, France, 29 May–3 Jun 2022, IAHS2022-617, https://doi.org/10.5194/iahs2022-617, 2022.

Many hydrological models (GR4J, Sacramento and SIMHYD for example) currently exist to reproduce hydrological response at a catchment scale. Some models (IQQM, Source for example) also exist to assess the impacts of human interventions designed to in some way optimise the use of water in regulated river systems. There are however a much smaller number of models designed to assess the impacts of water resources management on socio-economics, the community and the environment more broadly.

A current program of work known as MD-WERP – the Murray-Darling Water and Environment Research Program, seeks to improve the understanding and representation of key processes in hydrological models used to underpin basin analysis and planning. We are working with policy makers and water managers in State and Federal government to apply these models to assess the impacts of water resource management options on hydrological, ecological and socio-economic outcomes in the Murray-Darling Basin. This will allow planners to consider a wide range of management options in the review and revision of the Murray-Darling Basin Plan that is scheduled for the next few years.

The vast majority of global and regional climate models, as well as understanding of changes in global and regional circulation patterns suggest a drier future for the Murray-Darling Basin with consequently more frequent and severe droughts. The management options to be assessed therefore are primarily those that minimise the impacts of drier conditions on the environment, irrigators and the Basin community, along with models that allow assessments of trade-offs between these disparate water users to be made.

The models that are required to assess these adaptation options need to be diverse, covering not only things such as changes in rainfall and hydrological response, but also climate adaptation options in river system operations, conjunctive use of groundwater and surface water, water trading and allocation, and consequent impacts on the environment, irrigators, basin communities and First Nations groups.

This presentation will provide an overview of MD-WERP with a focus on the climate adaptation and hydrology themes, assessing how modelling tools can be used to better inform Basin-wide water resources policy and planning.

How to cite: Post, D., Robertson, D., Lester, R., and Chiew, F.: Research to support water resources planning in the Murray-Darling Basin, IAHS-AISH Scientific Assembly 2022, Montpellier, France, 29 May–3 Jun 2022, IAHS2022-120, https://doi.org/10.5194/iahs2022-120, 2022.

The last 20 years have seen the Murray-Darling basin under increased environmental stress due to land clearing, flow alteration, increased water allocations, and the growing impacts of climate change. Policy measures have been established to address this problem (e.g. The Water Act, The Basin Plan). However, the management of environmental water allocations remains a challenging task that requires estimates of current and future water availability, as well as an understanding of how environmental water releases will impact ecosystem health. Currently available environmental modelling is not well suited to support these day-to-day management decisions as the focus is predominantly on long-term environmental outcomes. There is a need for real-time predictive ecological models that operate at a shorter forecast horizon to directly meet the needs of environmental managers. This project aims to develop the science which would underpin a real-time ecological forecast for the Northern Murray-Darling Basin. 

Our aim is to develop a real-time ecological forecasting service in the Northern Murray-Darling Basin built on top of existing hydrological services such as the Australian Water Outlook (https://awo.bom.gov.au/) operated by the Bureau of Meteorology. The new service will output estimated ecological health indices with fully specified uncertainties. The Northern Basin includes significant environmental assets and is an important part of overall basin management, yet has received relatively little attention from the scientific community. Based on modelling work undertaken by the ANU and CSIRO, the project will focus on vegetation in the Narran Lakes, a site of high ecological and cultural value, which has been the focus of previous comparable research.

This research will also link to a study of the impact of water quality on small, rural communities in the region. These communities have a substantial Indigenous population and have a low socioeconomic status. Community water concerns include access to potable water as well as water suitable for washing, cooking and bathing. The aim is to develop integrated water quality-health models to project future water quality conditions (with confidence intervals) for selected locations. Improved flow and ecological forecasting developed in the project will be an important contribution to this research.

How to cite: Savage, C., Liu, M., Croke, B., Lerat, J., and Jakeman, A.: Developing a real-time ecological forecast for the Northern Murray-Darling Basin, IAHS-AISH Scientific Assembly 2022, Montpellier, France, 29 May–3 Jun 2022, IAHS2022-137, https://doi.org/10.5194/iahs2022-137, 2022.