An overview of monitoring methods for assessing the performance of nature-based solutions against natural hazards

To bring to fruition the capability of nature-based solutions (NBS) in mitigating hydro-meteorological risks (HMRs) and facilitate their widespread uptake require a consolidated knowledge-base related to their monitoring methods, efficiency, functioning and the ecosystem services they provide. We attempt to fill this knowledge gap by reviewing and compiling the existing scientific literature on methods, including ground-based measurements (e.g. gauging stations, wireless sensor network) and remote sensing observations (e.g. from topographic LiDAR, multispectral and radar sensors) that have been used and/or can be relevant to monitor the performance of NBS against five HMRs: floods, droughts, heatwaves, landslides, and storm surges and coastal erosion. These can allow the mapping of the risks and impacts of the specific hydro-meteorological events. We found that the selection and application of monitoring methods mostly rely on the particular NBS being monitored, resource availability (e.g. time, budget, space) and type of HMRs. No standalone method currently exists that can allow monitoring the performance of NBS in its broadest view. However, equipments, tools and technologies developed for other purposes, such as for ground-based measurements and atmospheric observations, can be applied to accurately monitor the performance of NBS to mitigate HMRs. We also focused on the capabilities of passive and active remote sensing, pointing out their associated opportunities and difficulties for NBS monitoring application. We conclude that the advancement in airborne and satellite-based remote sensing technology has signified a leap in the systematic monitoring of NBS performance, as well as provided a robust way for the spatial and temporal comparison of NBS intervention versus its absence. This improved performance measurement can support the evaluation of existing uncertainty and scepticism in selecting NBS over the artificially built concrete structures or grey approaches by addressing the questions of performance precariousness. Remote sensing technical developments, however, take time to shift toward a state of operational readiness for monitoring the progress of NBS in place (e.g. green NBS growth rate, their changes and effectiveness through time). More research is required to develop a holistic approach, which could routinely and continually monitor the performance of NBS over a large scale of intervention. This performance evaluation could increase the ecological and socio-economic benefits of NBS, and also create high levels of their acceptance and confidence by overcoming potential scepticism of NBS implementations

Review of Published Climate Change Adaptation and Mitigation Measures Related with Water

Stronger manifestation of climate change impact on global water cycle, water resources, and aquatic ecosystems has given a strong impetus to the development of adaptation measures in water management. The present report gives an insight to potential and planned water related measures tackling climate change causes and consequences, which have been included in the Member States River Basin Management Plans, published in various reports and scientific literature mostly within the last decade. The database of about 450 measures analysed in this report and given in a separate Annex as an Excel spreadsheet, constitutes the most important part of this deliverable. In the context of this report, measures are defined as practical steps or actions taken to (i) reduce the sources or enhance the sinks of greenhouse gases, (ii) to decrease the vulnerability of water resources and aquatic ecosystems to climate change, or (iii) enhance the knowledge base on climate-water relationships and increase the societal capacity to take right decisions on this matter. By strategic approach, the measures belong either to planned adaptation, which specifically focuses on climate change and variability, and autonomous adaptation, which goals are not specifically climate related, but have an added value in improving resilience to climate change. Separate chapters are dedicated to each of the five specific adaptation strategies addressed in the REFRESH Project. The present report is of relevance to the 7th EU Framework Programme, Theme 6 (Environment including Climate Change) project REFRESH (Adaptive strategies to Mitigate the Impacts of Climate Change on European Freshwater Ecosystems, Contract No.: 244121), to JRC Thematic Area 3 (Sustainable management of natural resources) foci on CC, to the European Clearing House mechanism on CC, and to the EC Blueprint on Water.JRC.DDG.H.5-Rural, water and ecosystem resource

Characterization of flowpaths to improve the prediction of vegetation impacts on hydrological processes in semi-arid mountainous catchments of the Cape Fold Belt

Philosophiae Doctor - PhDMountainous areas are important water sources in many landscapes. An understanding of how mountainous catchments function is important particularly in semi-arid areas, where water shortages are prevalent. In addition to climate and physiographic factors, the hydrological responses of mountainous catchments can be influenced by land uses and land cover types. Although the general effects of land use and land cover types on hydrological processes are known, prediction of the specific effects in a given catchment is still problematic. This study characterized flowpaths, and hydrological responses to different land cover types in a semi-arid, mountainous Kromme River catchment (Eastern Cape province of South Africa), located in the Cape Fold Mountains of the Table Mountain Group (TMG) geological region

Forecasting the response of Earth's surface to future climatic and land use changes: a review of methods and research needs

In the future, Earth will be warmer, precipitation events will be more extreme, global mean sea level will rise, and many arid and semiarid regions will be drier. Human modifications of landscapes will also occur at an accelerated rate as developed areas increase in size and population density. We now have gridded global forecasts, being continually improved, of the climatic and land use changes (C&LUC) that are likely to occur in the coming decades. However, besides a few exceptions, consensus forecasts do not exist for how these C&LUC will likely impact Earth-surface processes and hazards. In some cases, we have the tools to forecast the geomorphic responses to likely future C&LUC. Fully exploiting these models and utilizing these tools will require close collaboration among Earth-surface scientists and Earth-system modelers. This paper assesses the state-of-the-art tools and data that are being used or could be used to forecast changes in the state of Earth's surface as a result of likely future C&LUC. We also propose strategies for filling key knowledge gaps, emphasizing where additional basic research and/or collaboration across disciplines are necessary. The main body of the paper addresses cross-cutting issues, including the importance of nonlinear/threshold-dominated interactions among topography, vegetation, and sediment transport, as well as the importance of alternate stable states and extreme, rare events for understanding and forecasting Earth-surface response to C&LUC. Five supplements delve into different scales or process zones (global-scale assessments and fluvial, aeolian, glacial/periglacial, and coastal process zones) in detail

Interactions between land use and flood management in the Chi River Basin

The damages and hardships caused by floods and flooding remain an issue and are continuously increasing in the Chi River Basin, Thailand. It is difficult to make an accurate assessment of the costs and consequences associated with floods. However, flood hazards can also be seen as an opportunity, a chance to correct possible flaws and ambiguities in the flood management. The Chi River system cannot handle the regularly occurring floods, consequently, flooding of the low-lying areas occurs on a regular basis. Therefore, an integrated flood management framework needs to be developed to minimize the negative effects of floods of different magnitude. In response, a hydrological model (SWAT) and a hydraulic (1D/2D SOBEK) model were integrated to simulate floods in detailed way and to analyse the current system. A reliable simulation of the river flows and inundated areas is an essential component of a holistic flood management plan. The developed modelling framework enabled to analyse the impact of different structural measures such as river normalisation, green river (bypass), and retention basin. In addition, non-structural measures including reservoir operation and spatial land use planning were assessed in their capability to protect people and valuable infrastructure. For each measure, several possible scenarios were tested and evaluated based on economic and technical efficiency criteria to determine the most promising and efficient scenario. However, effective interventions may involve a judicious combination of flood mitigation approaches, rather than reliance on a stand-alone solution. A truly optimum combination of aforesaid measures was then chosen since it could considerably reduce flood extent and its damage. Finally, the study illustrates the effects of land use changes on floods, which indicated little or no significant potential impact on flood regime at river basin level, but rather at sub-basin scale. This finding is important for a better understanding of the scale and direction of impacts of developments in the future. Integrated land use planning was shown to be an essential component of a comprehensive flood management framework. &nbsp

Water Resources Management and Modeling

Hydrology is the science that deals with the processes governing the depletion and replenishment of water resources of the earth's land areas. The purpose of this book is to put together recent developments on hydrology and water resources engineering. First section covers surface water modeling and second section deals with groundwater modeling. The aim of this book is to focus attention on the management of surface water and groundwater resources. Meeting the challenges and the impact of climate change on water resources is also discussed in the book. Most chapters give insights into the interpretation of field information, development of models, the use of computational models based on analytical and numerical techniques, assessment of model performance and the use of these models for predictive purposes. It is written for the practicing professionals and students, mathematical modelers, hydrogeologists and water resources specialists

Green Infrastructure and Climate Change Adaptation

This open access book introduces the function, implementation and governance of green infrastructure in Japan and other countries where lands are geologically fragile and climatologically susceptible to climate change. It proposes green infrastructure as an adaptation strategy for climate change and biodiversity conservation. In the face of climate change, dams, levees and floodways built as disaster prevention facilities do not sufficiently function against extraordinary events such as mega-floods and tsunami disasters. To prevent those disasters and loss of biodiversity in various ecosystems, we should shift from conventional hard measures to more adaptive strategies using various functions that natural and semi-natural ecosystems provide. Green infrastructure is an interconnected network of waterways, wetlands, woodlands, wildlife habitats and other natural areas that support native species, maintain natural ecological processes, sustain air and water resources and contribute to the health and quality of life for communities and people. Green infrastructure has mainly been discussed from adaptation strategy perspectives in cities and urban areas. However, to protect cities, which are generally situated at downstream lower elevations, we explore the preservation and restoration of forests at headwater basins and wetlands along rivers from a catchment perspective. In addition, the quantitative examination of flood risk, biodiversity, and social-economic benefits described in this book brings new perspectives to the discussion. The aim of this book is to accelerate the transformative changes from gray-based adaptation strategies to green- or hybrid-based strategies to adapt to climate change. The book provides essential information on the structure, function, and maintenance of green infrastructure for scientists, university students, government officers, and practitioners

Fresh groundwater lenses in the Arabian Peninsula: formative, stability and management assessments, The

2019 Fall.Includes bibliographical references.The formation of fresh groundwater lenses (FGLs) overlying denser, saline or brackish groundwater is a fascinating hydrologic phenomenon that creates groundwater supplies of great potential value for humans and ecosystems in several formation settings, such as coastal areas, atoll islands, riverine floodplains, and subterranean oases in arid regions. In particular, FGLs in subterranean oases are a critical source of freshwater supply in arid regions, due to a general lack of perennial rivers and lakes. These FGLs are in danger of salinization due to natural events and anthropogenic stresses. Although extensive research has been conducted on FGLs in general, the FGLs in subterranean oases in arid regions have received less attention. Key knowledge gaps include the quantity and frequency of natural recharge to these FGLs; reliable estimates of environmental aquifer dispersivity at the scale of subterranean FGLs; the timing of lens development; and the impact of anthropogenic activities on lens dynamics. This dissertation focuses on the FGLs of subterranean oases in the Arabian Peninsula (AP), using the Rawdatain FGL in Kuwait as a case study. Among the FGLs in the AP, the Rawdatain FGL in Kuwait is perhaps a unique candidate because of its size and the availability of extensive subsurface data for the pre-development period. The main objectives of this study are as follows: (1) estimate long-term average annual recharge for the Rawdatain FGL and investigate the timing of lens depletion due to climate change; (2) provide a realistic range of longitudinal (αL), horizontal transverse (αh), and vertical transverse (αv) dispersivity values for the aquifer; and (3) assess the impacts of historical and future anthropogenic activities and evaluate artificial recharge alternatives for lens recovery storage (LSR). In this study, a 3D density-dependent groundwater flow and solute transport model using the SEAWAT modeling code is developed using the following pre-development period calibration targets: (1) groundwater head, (2) spatially-variable total dissolved solids (TDS) groundwater concentration, (3-5) three groundwater volume targets, (6-8) three vertical thickness targets of stored groundwater of three different water quality TDS ranges (0−700, 700−1000, and 1000−2000 mg/L), and (9) geometrical shape features of the lens along cross-sections. In addition, groundwater age data of the Rawdatain FGL was used as an independent factor to constrain the dispersivity and recharge rate during the simulated period of lens development. Moreover, a sensitivity analysis was performed to explore the effects of the hydraulic conductivity, boundary conditions, and vertical transverse dispersivity on lens geometry. Based on a comparison of twelve annual recharge amount scenarios using a constant recharge mechanism (CRM) (R1 to R12: 0.2 to 5.0 million m³/year) with data targets, the R5 (0.5 million m³/year) recharge scenario is selected to represent the long-term average annual recharge. These results demonstrated that the annual natural replenishment of the Rawdatain FGL is minimal compared with its size. A macro-scale stability assessment shows that a 50% reduction in annual recharge within a 100-year time frame would reduce the lens volumes by 21%, 17% and 9% for the three water quality categories. A multi-criteria score-based method was performed to rank the best performance of 28 dispersivity sets (D1 to D28: 1 to 500 m) among all of the targets with an equal weight, on a scale of 0 to 300 x 106 m3. The results illustrated that the D16 dispersivity set (αL = 50 m: αh = 5 m: αv = 0.1 m) represents the best large-scale environmental dispersivity values for the Rawdatain FGL and can be used for analyzing the natural mixing between the ambient brackish water and fresh water. A new baseline model for the predevelopment period using a pulse recharge mechanism (PRM) was established to assess the recharge frequency along with the longitudinal dispersivity. The results revealed that the 50 m longitudinal dispersivity set and one pulse recharge every two years had the best performance, and they were selected to simulate the effects of the infrequent rainfall events and anthropogenic impacts simultaneously. During the groundwater abstraction from 1963 to 2018, the reduction in the stored volumes was 28%, 17% and 12% for the three quality categories. The future pumping scenarios (2019-2100) suggested that the 0.16×106 m3/year is a suitable alternative for long-term use, 0.5×106 m³/year)is an appropriate option for short-term use, and extraction scenarios greater than 1.0×106 m³/year will cause a remarkable degeneration of the Rawdatain FGL. Artificial recharge scenarios (2019-2028) imply that a successful LSR for the Rawdatain FGL depends on selecting appropriate well locations and amounts of injected water. For instance, the I2 alternative could achieve a 100% storage recovery within 7.5, 8 and 9 years for the three water quality categories. This study provides a first attempt to model the formation of a FGL, assess the historical anthropogenic stresses, and evaluate future management scenarios in subterranean oases in arid regions. Implementing multiple data targets and water age is a unique process of calibration that was helpful in eliminating several non-unique calibration parameters and in decreasing the uncertainty of the calibrated parameters. The methodology presented herein provides a general approach that can be extrapolated to other FGLs with similar climatic and environmental circumstances. The outputs of this dissertation enhance the understanding of the formation, stability, and management of these lenses and will be very valuable to water managers for establishing appropriate water supply plans for these valuable water reserves, leading to preferable future water security in the AP

A baseline appraisal of water-dependant ecosystem services, the roles they play within desakota livelihood systems and their potential sensitivity to climate change

This report forms part of a larger research programme on 'Reinterpreting the Urban-Rural Continuum', which conceptualises and investigates current knowledge and research gaps concerning 'the role that ecosystems services play in the livelihoods of the poor in regions undergoing rapid change'. The report aims to conduct a baseline appraisal of water-dependant ecosystem services, the roles they play within desakota livelihood systems and their potential sensitivity to climate change. The appraisal is conducted at three spatial scales: global, regional (four consortia areas), and meso scale (case studies within the four regions). At all three scales of analysis water resources form the interweaving theme because water provides a vital provisioning service for people, supports all other ecosystem processes and because water resources are forecast to be severely affected under climate change scenarios. This report, combined with an Endnote library of over 1100 scientific papers, provides an annotated bibliography of water-dependant ecosystem services, the roles they play within desakota livelihood systems and their potential sensitivity to climate change. After an introductory, section, Section 2 of the report defines water-related ecosystem services and how these are affected by human activities. Current knowledge and research gaps are then explored in relation to global scale climate and related hydrological changes (e.g. floods, droughts, flow regimes) (section 3). The report then discusses the impacts of climate changes on the ESPA regions, emphasising potential responses of biomes to the combined effects of climate change and human activities (particularly land use and management), and how these effects coupled with water store and flow regime manipulation by humans may affect the functioning of catchments and their ecosystem services (section 4). Finally, at the meso-scale, case studies are presented from within the ESPA regions to illustrate the close coupling of human activities and catchment performance in the context of environmental change (section 5). At the end of each section, research needs are identified and justified. These research needs are then amalgamated in section 6