Staff Publications

Staff Publications

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    'Staff publications' is the digital repository of Wageningen University & Research

    'Staff publications' contains references to publications authored by Wageningen University staff from 1976 onward.

    Publications authored by the staff of the Research Institutes are available from 1995 onwards.

    Full text documents are added when available. The database is updated daily and currently holds about 240,000 items, of which 72,000 in open access.

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Using the ecosystem services concept to analyse stakeholder involvement in wetland management
Cohen-Shacham, E. ; Dayan, T. ; Groot, R.S. de; Beltrame, C. ; Guillet, F. ; Feitelson, E. - \ 2015
Wetlands Ecology and Management 23 (2015)2. - ISSN 0923-4861 - p. 241 - 256.
water management - israel - hula - typology - basin - lake
Wetland management usually involves multiple stakeholders. This paper describes how the use of the ecosystem services (ES) concept can help to identify the main stakeholders associated with wetland conservation, using the Hula Wetland in the Sea of Galilee’s watershed as a case study. We conducted a stakeholder analysis based on semi-structured interviews. We focused on the management of two semi-natural areas within the larger Hula Wetland area (Hula Nature Reserve and Agamon), in which different management regimes are used and which provide different bundles of ES to different stakeholders. Using the ES concept in the stakeholder analysis, we were able to present the Hula Wetland management in a comprehensive manner. The approach also revealed a lack of coordination between the managing organisations which might lead to competition favouring cultural services (in particular tourism) at the expense of habitat services (i.e. biodiversity conservation) in the future. To test our method we also conducted a stakeholder analysis in the Camargue Wetland in France. The two wetlands have similar characteristics but are embedded in different institutional contexts. The Camargue Regional Park has a multi-stakeholder platform which could serve as an example for the Hula Wetland to improve its management and lead to better coordination and complementarity of ES provided by the two sub-sites. Our study showed that applying the ES concept helps to quickly identify relevant stakeholders and analyse wetland management in a more holistic way and to point towards sustainable solutions for conflicting stakeholder interests.
Integrating ecosystem services and climate change responses in coastal wetlands development plans for Bangladesh
Sarwar, M.H. ; Hein, L.G. ; Rip, F.I. ; Dearing, J.A. - \ 2015
Mitigation and Adaptation Strategies for Global Change 20 (2015)2. - ISSN 1381-2386 - p. 241 - 261.
adaptation - impacts - vulnerability - management - framework - mexico - system - basin
This study explores the integration of ecosystem services and climate change adaptation in development plans for coastal wetlands in Bangladesh. A new response framework for adaptation is proposed, based on an empirical analysis and consultations with stakeholders, using a modified version of the DPSIR (Driver-Pressure-State-Impact-Response) framework. The framework is tested in the Narail district of Bangladesh, where temperature has increased by about 1 °C in the summer in combination with an increase in rainfall of 0.70 mm day-1 yr-1 in the last decade. Calibrated model (MAGICC/SENGEN) projections forecast, on average, a temperature increase of up to 5 °C and an increase in rainfall of 25 % by the end of this century. Water diversion in the upstream regions of the Ganges River delta contributes to increase water scarcity in the dry season. Enhanced rainfall and the immense pressure of water discharges from upstream water sources are increasing the risk of floods and river erosion in the dry season. An increase in the water holding capacity of rivers, wetlands and canals by dredging is urgently required. The empirical model of this study is intended to support adaptation planning and monitoring in Bangladesh and can be used in other data-poor areas which will suffer from climate change.
Accounting for environmental flow requirements in global water assessments
Pastor, A.V. ; Ludwig, F. ; Biemans, H. ; Hoff, H. ; Kabat, P. - \ 2014
Hydrology and Earth System Sciences 18 (2014)12. - ISSN 1027-5606 - p. 5041 - 5059.
fish species richness - climate-change - hydrological model - river ecosystems - vegetation model - biodiversity - management - resources - regimes - basin
As the water requirement for food production and other human needs grows, quantification of environmental flow requirements (EFRs) is necessary to assess the amount of water needed to sustain freshwater ecosystems. EFRs are the result of the quantification of water necessary to sustain the riverine ecosystem, which is calculated from the mean of an environmental flow (EF) method. In this study, five EF methods for calculating EFRs were compared with 11 case studies of locally assessed EFRs. We used three existing methods (Smakhtin, Tennant, and Tessmann) and two newly developed methods (the variable monthly flow method (VMF) and the Q90_Q50 method). All methods were compared globally and validated at local scales while mimicking the natural flow regime. The VMF and the Tessmann methods use algorithms to classify the flow regime into high, intermediate, and low-flow months and they take into account intra-annual variability by allocating EFRs with a percentage of mean monthly flow (MMF). The Q90_Q50 method allocates annual flow quantiles (Q90 and Q50) depending on the flow season. The results showed that, on average, 37% of annual discharge was required to sustain environmental flow requirement. More water is needed for environmental flows during low-flow periods (46–71% of average low-flows) compared to high-flow periods (17–45% of average high-flows). Environmental flow requirements estimates from the Tennant, Q90_Q50, and Smakhtin methods were higher than the locally calculated EFRs for river systems with relatively stable flows and were lower than the locally calculated EFRs for rivers with variable flows. The VMF and Tessmann methods showed the highest correlation with the locally calculated EFRs (R2=0.91). The main difference between the Tessmann and VMF methods is that the Tessmann method allocates all water to EFRs in low-flow periods while the VMF method allocates 60% of the flow in low-flow periods. Thus, other water sectors such as irrigation can withdraw up to 40% of the flow during the low-flow season and freshwater ecosystems can still be kept in reasonable ecological condition. The global applicability of the five methods was tested using the global vegetation and the Lund-Potsdam-Jena managed land (LPJmL) hydrological model. The calculated global annual EFRs for fair ecological conditions represent between 25 and 46% of mean annual flow (MAF). Variable flow regimes, such as the Nile, have lower EFRs (ranging from 12 to 48% of MAF) than stable tropical regimes such as the Amazon (which has EFRs ranging from 30 to 67% of MAF).
Legal pluralism, hydraulic property creation and sustainability: the materialized nature of water rights in user-managed systems
Boelens, R.A. ; Vos, J.M.C. - \ 2014
Current Opinion in Environmental Sustainability 11 (2014). - ISSN 1877-3435 - p. 55 - 62.
irrigation systems - collective action - ecuadorian andes - governance - resources - community - valley - basin - peru - resistance
Worldwide, most irrigation systems are managed by farmer collectives, in contexts of legal pluralism. National and supranational legislation and policy-making, however, focus on governance frameworks established by State and market actors. Consequently, development planning often ignores farmers’ rationality regarding sustainable water control. This paper's literature research examines how the notion of ‘hydraulic property creation’ in contexts of legal pluralism may support sustainable, self-governed irrigation systems. User-investment in hydraulic infrastructure generates collective water property relations. This socio-natural foundation of farmer-managed systems embeds (materializes) and entwines collective and individual water rights in hydraulic works, triggering collective action. Being fundamental to sustainable management, even well-intended policies and legislation ignoring this practice-based property notion may jeopardize well-functioning systems
Markedly divergent estimates of Amazon forest carbon density from ground plots and satellites
Mitchard, E.T.A. ; Feldpausch, T.R. ; Brienen, R.J.W. ; Lopez-Gonzalez, G. ; Monteagudo, A. ; Baker, T.R. ; Lewis, S.L. ; Poorter, L. ; Peña-Claros, M. - \ 2014
Global Ecology and Biogeography 23 (2014)8. - ISSN 1466-822X - p. 935 - 946.
aboveground live biomass - stocks - deforestation - emissions - allometry - patterns - basin - soils
Aim The accurate mapping of forest carbon stocks is essential for understanding the global carbon cycle, for assessing emissions from deforestation, and for rational land-use planning. Remote sensing (RS) is currently the key tool for this purpose, but RS does not estimate vegetation biomass directly, and thus may miss significant spatial variations in forest structure. We test the stated accuracy of pantropical carbon maps using a large independent field dataset. Location Tropical forests of the Amazon basin. The permanent archive of the field plot data can be accessed at: Methods Two recent pantropical RS maps of vegetation carbon are compared to a unique ground-plot dataset, involving tree measurements in 413 large inventory plots located in nine countries. The RS maps were compared directly to field plots, and kriging of the field data was used to allow area-based comparisons. Results The two RS carbon maps fail to capture the main gradient in Amazon forest carbon detected using 413 ground plots, from the densely wooded tall forests of the north-east, to the light-wooded, shorter forests of the south-west. The differences between plots and RS maps far exceed the uncertainties given in these studies, with whole regions over- or under-estimated by >¿25%, whereas regional uncertainties for the maps were reported to be
Modelling centennial sediment waves in an eroding landscape – catchment complexity
Schoorl, J.M. ; Temme, A.J.A.M. ; Veldkamp, A. - \ 2014
Earth Surface Processes and Landforms 39 (2014)11. - ISSN 0197-9337 - p. 1526 - 1537.
self-organized criticality - soil redistribution - late pleistocene - fluvial systems - dem resolution - evolution - geomorphology - climate - level - basin
Sediment flux dynamics in fluvial systems have often been related to changes in external drivers of topography, climate or land cover. It is well known that these dynamics are non-linear. Recently, model simulations of fluvial activity and landscape evolution have suggested that self-organization in landscapes can also cause internal complexity in the sedimentary record. In this contribution one particular case of self-organization is explored in the Sabinal field study area, Spain, where several dynamic zones of sedimentation and incision are observed along the current river bed. Whether these zones can be caused by internal complexity was tested with landscape evolution model (LEM) LAPSUS (Landscape Process Modelling at Multi-dimensions and Scales). During various 500¿year simulations, zones of sedimentation appear to move upstream and downstream in eroding river channels (‘waves’). These waves are visualized and characterized for a range of model settings under constant external forcing, and the self-organizing process behind their occurrence is analysed. Results indicate that this process is not necessarily related to simplifications in the model and is more generic than the process of bed-armouring that has recently been recognized as a cause for complexity in LEM simulations. We conclude that autogenic sediment waves are the result of the spatial propagation in time of feedbacks in local transport limited (deposition) and detachment limited (erosion) conditions
Disentangling the impacts of climate change, land use change and irrigation on the Central Rift Valley water system of Ethiopia
Getnet Debas, M. ; Hengsdijk, H. ; Ittersum, M.K. van - \ 2014
Agricultural Water Management 137 (2014). - ISSN 0378-3774 - p. 104 - 115.
kenya - basin - model - simulation - hydrology - support - lakes
The Central Rift Valley (CRV) of Ethiopia is a closed basin where claims on land and water have strongly increased over the past decade resulting in over-exploitation of the resources: a clear symptom is the declining trend in the water level of the terminal Lake Abyata. In this paper, we quantify the plausible recent impacts of climate change, land use change and irrigation water abstraction on water availability of Lake Abyata. We examined trends in lake levels, river discharges, basin rainfall, temperature and irrigation development (ca. 1975–2008), and computed the additional evapotranspiration loss resulting from temperature change and irrigated land. We also analysed land use change (1990–2007) and estimated the subsequent change in surface runoff. Temperature has increased linearly over 34 years (p <0.001) whereas rainfall has not changed significantly. Consequently, increased evapotranspiration consumed 62 and 145 Mm3 of additional water from lakes and land surface, respectively, during 1990–2007. Furthermore, an estimated 285 Mm3 yr-1 of water was abstracted for irrigation in 2009 of which approximately 170 Mm3 yr-1 is irrecoverable evapotranspiration loss. In addition, surface runoff has increased in the upper, and decreased in lower sub-basins of the CRV associated with extensive land use change (1990–2007). However, insight in the impact of the net increase in runoff of 260 Mm3 yr-1 on the water availability for Lake Abyata remains partial because of data and methodological limitations. We conclude that the potential for agricultural intensification and its hydrological implications should be considered jointly to prevent further deteriorating Lake Abyata.
Reducing future nutrient inputs to the Black Sea
Strokal, M. ; Kroeze, C. ; Kopilevych, V.A. ; Voytenko, L.V. - \ 2014
Science of the Total Environment 466-467 (2014). - ISSN 0048-9697 - p. 253 - 264.
danube river - spatially explicit - coastal waters - global-model - basin - export - management - nitrogen - trends - china
Rivers export increasing amounts of dissolved inorganic (DIN, DIP) and organic (DON, DOP) nitrogen and phosphorus to the Black Sea causing coastal eutrophication. The aim of this study is to explore future trends in river export of these nutrients to the sea through a sensitivity analysis. We used the Global NEWS (Nutrient Export from WaterSheds) model to this end. We calculated that between 2000 and 2050 nutrient inputs to the Black Sea may increase or decrease, depending on the assumed environmental management. We analyzed the effects of agricultural and sewage management on nutrient inputs to the sea in 2050 relative to two Millennium Ecosystem Assessment (MEA) scenarios, Global Orchestration (GO) and Adaptive Mosaic (AM). In these baselines, total N and P inputs to the Black Sea decrease between 2000 and 2050, but not for all rivers and nutrient forms. Our results indicate that it is possible to reduce nutrient inputs to the sea further between 2000 and 2050 in particular for dissolved inorganic N and P and for many river basins, but not for all. For scenarios assuming combined agricultural and sewage management dissolved inorganic N and P inputs to the Black Sea are reduced by up to two-thirds between 2000 and 2050 and dissolved organic N and P inputs by one-third. River export of DIN is mainly affected by agricultural management and that of DIP by sewage management. On the other hand, in scenarios assuming increased fertilizer use for, for instance bioenergy crops, nutrient inputs to the sea increase. An increase in DIP inputs by southern rivers seems difficult to avoid because of the increasing number of people connected to sewage systems.
Impact assessment of land use policies: Introduction
Bezlepkina, I. ; Brouwer, F.M. ; Reidsma, P. - \ 2014
Land Use Policy 37 (2014). - ISSN 0264-8377 - p. 1 - 5.
integrated assessment - systems - sustainability - framework - basin - china
This special issue is built around a series of impact assessments of land use policies and sustainable development in developing countries, carried out in the EU-funded project LUPIS (Sixth framework programme, Global Change and Ecosystems, Contract 36955). The project targeted at the development and testing of impact assessment tools of land-use-related policies in seven developing countries: Brazil, India, China, Indonesia, Kenya, Mali and Tunisia. This issue presents the current understanding of ex-ante assessment and includes contributions with comparative work across several countries, and case studies in individual countries, addressing important land-use related concerns.
The Effects of Groundwater and Surface Water Use on Total Water Availability and Implication for Water Management: The Case of Lake Naivasha, Kenya
Oel, P.R. van; Mulatu, D.W. ; Odongo, V.O. ; Meins, F.M. ; Hogeboom, R.J. ; Brecht, R. ; Stein, A. ; Onyando, J.O. ; Veen, A. van der - \ 2013
Water Resources Management 27 (2013)9. - ISSN 0920-4741 - p. 3477 - 3492.
resources management - human impact - basin
This study discusses the effects of water abstractions from two alternative sources on the available water volume around Lake Naivasha, Kenya: the lake itself and a connected aquifer. An estimation of the water abstraction pattern for the period 1999–2010 is made and its effect on the available water volume in Lake Naivasha and its connected aquifer is evaluated using a simple water balance modeling approach. This study shows that accurate estimates of annual volume changes of Lake Naivasha can be made using a simple monthly water balance approach that takes into account the exchange of water between the lake and its connected aquifer. The amount of water that is used for irrigation in the area around Lake Naivasha has a substantial adverse effect on the availability of water. Simulation results of our simple water balance model suggests that abstractions from groundwater affect the lake volume less than direct abstractions from the lake. Groundwater volumes, in contrast, are much more affected by groundwater abstractions and therefore lead to much lower groundwater levels. Moreover, when groundwater is used instead of surface water, evaporation losses from the lake are potentially higher due to a larger lake surface area. If that would be the case then the overall water availability in the area is more strongly affected by the abstraction of groundwater than by the abstraction of surface water. Therefore water managers should be cautious when using lake levels as the only indicator of water availability for restricting water abstractions.
Changing monsoon patterns, snow and glacial melt, its impacts and adaptation options in northern India: Synthesis
Moors, E.J. ; Stoffel, M. - \ 2013
Science of the Total Environment 468-469 (2013)Suppl.. - ISSN 0048-9697 - p. S162 - S167.
climate-change - water-resources - human health - basin
This paper gives a synthesis of this special issue on the sensitivity to climate change of the main bio-physical processes in the Hindukush–Karakoram–Himalayas. It also describes the impacts on the water resources with a special focus on the Ganges. Consequences of changes in water resources and possible adaptation measures for different sectors are discussed.
Making the distinction between water scarcity and drought using an observation-modeling framework
Loon, A.F. van; Lanen, H.A.J. van - \ 2013
Water Resources Research 49 (2013)3. - ISSN 0043-1397 - p. 1483 - 1502.
decision-support-system - climate-change - hydrological drought - resource-management - central spain - runoff model - forcing data - groundwater - river - basin
Drought and water scarcity are keywords for river basin management in water-stressed regions. “Drought” is a natural hazard, caused by large-scale climatic variability, and cannot be prevented by local water management. “Water scarcity” refers to the long-term unsustainable use of water resources, which water managers can influence. Making the distinction between drought and water scarcity is not trivial, because they often occur simultaneously. In this paper, we propose an observation-modeling framework to separate natural (drought) and human (water scarcity) effects on the hydrological system. The basis of the framework is simulation of the situation that would have occurred without human influence, the “naturalized” situation, using a hydrological model. The resulting time series of naturalized state variables and fluxes are then compared to observed time series. As second, more important and novel step, anomalies (i.e., deviations from a threshold) are determined from both time series and compared. We demonstrate the use of the proposed observation-modeling framework in the Upper-Guadiana catchment in Spain. Application of the framework to the period 1980–2000 shows that the impact of groundwater abstraction on the hydrological system was, on average, four times as high as the impact of drought. Water scarcity resulted in disappearance of the winter high-flow period, even in relatively wet years, and a nonlinear response of groundwater. The proposed observation-modeling framework helps water managers in water-stressed regions to quantify the relative impact of drought and water scarcity on a transient basis and, consequently, to make decisions regarding adaptation to drought and combating water scarcity.
Assessing riparian zone impacts on water and sediment movement: A new approach
Keesstra, S.D. ; Kondrlova, E. ; Czaika, A. ; Seeger, K.M. ; Maroulis, J. - \ 2012
Netherlands journal of geosciences 91 (2012)1-2. - ISSN 0016-7746 - p. 245 - 255.
river restoration - fluvial geomorphology - bank erosion - sw slovenia - california - vegetation - catchment - transport - yield - basin
The state of river channels and their riparian zones in terms of geomorphology and vegetation has a significant effect on water and sediment transport in headwater catchments. High roughness in natural rivers due to vegetation and geomorphological attributes generate drag on flowing water. This drag will slow water discharge, which in turn influences the sediment dynamics of the flow. The impacts of changes in the management of rivers and their riparian zone (either by catchment managers or river restoration plans) impacts both up- as well as downstream reaches, and should be assessed holistically prior to the implementation of these plans. To assess the river's current state as well as any possible changes in geomorphology and vegetation in and around the river, effective approaches to characterise the river are needed. In this paper, we present a practical approach for making detailed surveys of relevant river attributes. This methodology has the benefit of being both detailed - describing river depth, width, channel morphology, erosive features and vegetation types - but also being practical in terms of time management. This is accomplished by identifying and describing characteristic benchmark reaches (typical sites) in detail against which the remainder of the river course can be rated. Using this method, a large river stretch can be assessed in a relatively short period while still retrieving high quality data for the total river course. In this way, models with high data requirements for assessing the condition of a river course, can be parameterised without major investments on field surveys. In a small headwater catchment (23 km(2)) in southwestern Poland, this field methodology was used to retrieve data to run an existing model (HEC-GeoRAS) which can assess the impact of changes in the riparian and channel vegetation and channel management on sedimentation processes and stream flow velocity. This model determines the impact of channel morphology and in-channel and riparian vegetation on stream flow and sediment transport. Using four return periods of flooding (2, 10, 20 and 100 years), two opposing channel management / morphology scenarios were run; a natural channel and a fully regulated channel. The modelling results show an increase in the effect of riparian vegetation / geomorphology with an increase in return period of the modeled peak discharge. More natural channel form and increased roughness reduces the stream flow velocity due to increasing drag from flow obstructions (vegetation and channel morphological features). The higher the flood water stage, the greater the drag due to vegetation on the floodplains of natural river reaches compared to channelised sections. Slower flow rates have an impact on sediment mobilisation and transport in the river.
Modelling sediment dynamics due to hillslope-river interactions: incorporating fluvial behaviour in landscape evolution model LAPSUS
Baartman, J.E.M. ; Gorp, W. van; Temme, A.J.A.M. ; Schoorl, J.M. - \ 2012
Earth Surface Processes and Landforms 37 (2012)9. - ISSN 0197-9337 - p. 923 - 935.
channel network growth - soil redistribution - cellular-model - dem resolution - basin - scales - water - reach
Landscape evolution models (LEMs) simulate the three-dimensional development of landscapes over time. Different LEMs have different foci, e.g. erosional behaviour, river dynamics, the fluvial domain, hillslopes or a combination. LEM LAPSUS is a relatively simple cellular model operating on timescales of centuries to millennia and using annual timesteps that has had a hillslope focus. Our objective was to incorporate fluvial behaviour in LAPSUS without changing the existing model equations. The model should be able to reproduce alternating aggradation and incision in the floodplains of catchments, depending on simulated conditions. Testing was done using an artificial digital elevation model (DEM) and a demonstration of the ability for fluvial simulation was performed for a real landscape (Torrealvilla catchment, southeast Spain). Model equations to calculate sediment dynamics and water routing were similar for both hillslope and fluvial conditions, but different parameter values were used for these domains, defined based on annual discharge. Parameters changing between the domains are convergence factor p, which is used in the multiple flow algorithm to route water, and discharge and gradient exponents m and n, used in transport capacity calculations. Erodibility and ‘sedimentability’ factors K and P were changed between cold (little vegetation, high erodibility) and warm conditions (more vegetation, lower erodibility). Results show that the adapted parameters reproduced alternating aggradation – due to divergent flow in the floodplain and sediment supply under cold conditions – and incision due to reduced sediment supply and resulting clean water erosion during simulated warm conditions. The simulated results are due to interactions between hillslopes and floodplains, as the former provide the sediments that are deposited in the latter. Similar behaviour was demonstrated when using the real DEM. Sensitivity and resolution analysis showed that the model is sensitive to changes in m, n and p and that model behaviour is influenced by DEM resolution.
The role of collective groundwater institutions in the implementation of direct groundwater regulation measures in Minqin County, China
Aarnoudse, E. ; Bluemling, B. ; Wester, P. ; Qu, W. - \ 2012
Hydrogeology Journal 20 (2012)7. - ISSN 1431-2174 - p. 1213 - 1221.
user associations - management - governance - policies - basin
Direct groundwater regulation (e.g. registration of abstraction points, permits and concessions) has been much advocated world-wide; however, few successful cases have been reported. The development of groundwater use in Minqin County, Gansu Province, China, is described, with analyses of the situation before and after the implementation of direct groundwater regulation measures in 2007. Based on a survey carried out in 2010, it is argued that the regulation measures, which were part of a broader water-policy reform, were successfully implemented due to their integration with pre-existing collective groundwater institutions. In addition to the regulation measures-the closure of wells and per capita water use restriction-all villages had to form water users' associations (WUAs) which were assigned to implement the new regulations. These WUAs were found to have the same structure as the existing collective groundwater institutions. Through the water-policy reform, the function of the pre-existing groundwater institutions was transformed from managing "water exploitation" to managing "water conservation".
Vegetation NDVI Linked to Temperature and Precipitation in the Upper Catchments of Yellow River
Hao, F. ; Zhang, X. ; Ouyang, W. ; Skidmore, A.K. ; Toxopeus, A.G. - \ 2012
Environmental Modeling and Assessment 17 (2012)4. - ISSN 1420-2026 - p. 389 - 398.
land-cover changes - qinghai-xizang plateau - net primary production - central new-mexico - tibetan plateau - modis - china - soil - climate - basin
Vegetation in the upper catchment of Yellow River is critical for the ecological stability of the whole watershed. The dominant vegetation cover types in this region are grassland and forest, which can strongly influence the eco-environmental status of the whole watershed. The normalized difference vegetation index (NDVI) for grassland and forest has been calculated and its daily correlation models were deduced by Moderate Resolution Imaging Spectroradiometer products on 12 dates in 2000, 2003, and 2006. The responses of the NDVI values with the inter-annual grassland and forest to three climatic indices (i.e., yearly precipitation and highest and lowest temperature) were analyzed showing that, except for the lowest temperature, the yearly precipitation and highest temperature had close correlations with the NDVI values of the two vegetation communities. The value of correlation coefficients ranged from 0.815 to 0.951 (p <0.01). Furthermore, the interactions of NDVI values of vegetation with the climatic indicators at monthly interval were analyzed. The NDVI of vegetation and three climatic indices had strong positive correlations (larger than 0.733, p <0.01). The monthly correlations also provided the threshold values for the three climatic indictors, to be used for simulating vegetation growth grassland under different climate features, which is essential for the assessment of the vegetation growth and for regional environmental management.
Seasonal evaluation of the land surface sheme HTESSEL against remote sensing derived energy fluxes of the Transdanubian regions in Hungary
Wipfler, E.L. ; Metselaar, K. ; Dam, J.C. van; Feddes, R.A. ; Meijgaard, E. van; Ulft, L.H. van; Hurk, B. van den; Zwart, S.J. ; Bastiaanssen, W.G.M. - \ 2011
Hydrology and Earth System Sciences 15 (2011)4. - ISSN 1027-5606 - p. 1257 - 1271.
aardoppervlak - evapotranspiratie - remote sensing - klimaatverandering - modellen - hongarije - land surface - evapotranspiration - climatic change - models - hungary - terrestrial water storage - era-40 reanalysis - balance closure - climate models - field - atmosphere - hydrology - impact - basin
The skill of the land surface model HTESSEL is assessed to reproduce evaporation in response to land surface characteristics and atmospheric forcing, both being spatially variable. Evaporation estimates for the 2005 growing season are inferred from satellite observations of the Western part of Hungary and compared to model outcomes. Atmospheric forcings are obtained from a hindcast run with the Regional Climate Model RACMO2. Although HTESSEL slightly underpredicts the seasonal evaporative fraction as compared to satellite estimates, the mean, 10th and 90th percentile of this variable are of the same magnitude as the satellite observations. The initial water as stored in the soil and snow layer does not have a significant effect on the statistical properties of the evaporative fraction. However, the spatial distribution of the initial soil and snow water significantly affects the spatial distribution of the calculated evaporative fraction and the models ability to reproduce evaporation correctly in low precipitation areas in the considered region. HTESSEL performs weaker in dryer areas. In Western Hungary these areas are situated in the Danube valley, which is partly covered by irrigated cropland and which also may be affected by shallow groundwater. Incorporating (lateral) groundwater flow and irrigation, processes that are not included now, may improve HTESSELs ability to predict evaporation correctly. Evaluation of the model skills using other test areas and larger evaluation periods is needed to confirm the results.
Spatial pattern and temporal variability of runoff processes in Mediterranean Mountain environments - a case study of the Central Spanish Pyrenees
Butzen, V. ; Seeger, K.M. ; Casper, M.C. - \ 2011
Zeitschrift für Geomorphologie 55 (2011)3. - ISSN 0372-8854 - p. 25 - 48.
catchment - generation - basin - moisture - behavior - spain
Mediterranean mountain environments like the Central Spanish Pyrenees show a highly variable rainfall-runoff response, mainly explained by the intense intra- and inter-annual variability of precipitation yield. This leads to a highly differentiated moisture status and therefore it is assumed to lead also to highly variable runoff contributing areas. For the identification of areas with certain dominant runoff processes in an experimental headwater catchment in which agriculture was abandoned several decades ago the concept of the topographical index was extended by means of weighting grids. These weighting rasters were generated using additional information on soils and vegetation. Runoff generating areas were identified widespread in the catchment, with Hortonian overland flow (HOF) dominating the runoff processes on degraded soils, and saturation overland flow (SOF) dominating the footslope areas, where hydromorphic soils were mapped. Rainfall-runoff experiments were performed to quantify runoff and erosion and to identify seasonal changes using experimental data gained in different seasons of the year. The seasonal changes in runoff response could be localised clearly within the areas of SOF, whereas the other ones showed a similar behaviour. This implied that the procedure of delineation had to be differentiated for dry and moist conditions, and that the SOF areas had to be reclassified as SSF/DP areas for dry conditions. Due to the location of these areas close to the ravine, we could explain the pronounced switching runoff behaviour of the catchment. GIS techniques combining different levels of topographic, soil and vegetation information showed to be suitable for delineation of areas with different runoff generation processes. The inclusion of seasonally distributed experimental data demonstrated that for dry conditions, slightly different methods have to be applied. Nevertheless, the study showed also the limitations of the combined methods: (I) subsurface flows and ground water recharge could only be deduced, not demonstrated, (II) finally, there is still a good knowledge of the area needed for an accurate process representation.
Impact of reservoirs on river discharge and irrigation water supply during the 20th century
Biemans, H. ; Haddeland, I. ; Kabat, P. ; Ludwig, F. ; Hutjes, R.W.A. - \ 2011
Water Resources Research 47 (2011)3. - ISSN 0043-1397 - 15 p.
global vegetation model - climate-change - integrated model - resources - dams - basin - requirements - groundwater - validation - sediment
This paper presents a quantitative estimation of the impact of reservoirs on discharge and irrigation water supply during the 20th century at global, continental, and river basin scale. Compared to a natural situation the combined effect of reservoir operation and irrigation extractions decreased mean annual discharge to oceans and significantly changed the timing of this discharge. For example, in Europe, May discharge decreased by 10%, while in February it increased by 8%. At the end of the 20th century, reservoir operations and irrigation extractions decreased annual global discharge by about 2.1% (930 km3 yr-1). Simulation results show that reservoirs contribute significantly to irrigation water supply in many regions. Basins that rely heavily on reservoir water are the Colorado and Columbia River basins in the United States and several large basins in India, China, and central Asia (e.g., in the Krishna and Huang He basins, reservoirs more than doubled surface water supply). Continents gaining the most are North America, Africa, and Asia, where reservoirs supplied 57, 22, and 360 km3 yr-1 respectively between 1981–2000, which is in all cases 40% more than the availability in the situation without reservoirs. Globally, the irrigation water supply from reservoirs increased from around 18 km3 yr-1 (adding 5% to surface water supply) at the beginning of the 20th century to 460 km3 yr-1 (adding almost 40% to surface water supply) at the end of the 20th century. The analysis is performed using a newly developed and validated reservoir operation scheme within a global-scale hydrology and vegetation model (LPJmL)
Different perceptions of adaptation to climate change: a mental model approach applied to the evidence from expert interviews
Otto-Banaszak, I. ; Matczak, P. ; Wesseler, J.H.H. ; Wechsung, F. - \ 2011
Regional Environmental Change 11 (2011)2. - ISSN 1436-3798 - p. 217 - 228.
perspectives - management - systems - views - basin
We argue that differences in the perception and governance of adaptation to climate change and extreme weather events are related to sets of beliefs and concepts through which people understand the environment and which are used to solve the problems they face (mental models). Using data gathered in 31 in-depth interviews with adaptation experts in Europe, we identify five basic stakeholder groups whose divergent aims and logic can be related to different mental models they use: advocacy groups, administration, politicians, researchers, and media and the public. Each of these groups uses specific interpretations of climate change and specifies how to deal with climate change impacts. We suggest that a deeper understanding and follow-up of the identified mental models might be useful for the design of any stakeholder involvement in future climate impact research processes. It might also foster consensus building about adequate adaptation measures against climate threats in a society.
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