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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Resilience of Amazonian forests : the roles of fire, flooding and climate
Monteiro Flores, B. - \ 2016
Wageningen University. Promotor(en): Marten Scheffer, co-promotor(en): Milena Holmgren Urba; Jose de Attayde. - Wageningen : Wageningen University - ISBN 9789462578876 - 128 p.
forests - resilience of nature - fire - flooding - floods - climate - floodplains - vegetation - amazonia - bossen - veerkracht van de natuur - brand - inundatie - overstromingen - klimaat - stroomvlakten - vegetatie

The Amazon has recently been portrayed as a resilient forest system based on quick recovery of biomass after human disturbance. Yet with climate change, the frequency of droughts and wildfires may increase, implying that parts of this massive forest may shift into a savanna state. Although the Amazon basin seems quite homogeneous, 14% is seasonally inundated. In my thesis I combine analyses of satellite data with field measurements and experiments to assess the role of floodplain ecosystems in shaping the resilience of Amazonian forests.

First, I analyse tree cover distribution for the whole Amazon to reveal that savannas are relatively more common on floodplains. This suggests that compared to uplands, floodplains spend more time in the savanna state. Also, floodplain forests seem to have a tipping point at 1500 mm of annual rainfall in which forests may shift to savanna, whereas the tipping point for upland forests seems to be at 1000 mm of rainfall. Combining satellite and field measurements, I show that the higher frequency of savannas on floodplain ecosystems may be due to a higher sensitivity to fire. After a forest fire, floodplains lose more tree cover and soil fertility, and recover more slowly than uplands (chapter 2).

In floodplains of the Negro river, I studied the recovery of blackwater forests after repeated fires, using field data on tree basal area, species richness, seed availability, and herbaceous cover. Results indicate that repeated fires may easily trap blackwater floodplains in an open-vegetation state, due the sudden loss of forest resilience after a second fire event (chapter 3).

Analyses of the soil and tree composition of burnt floodplain forests, reveal that a first fire is the onset of the loss of soil fertility that intensifies while savanna trees dominate the tree community. A tree compositional shift happens within four decades, possibly accelerated by fast nutrient leaching. The rapid savannization of floodplain forests after fire implies that certain mechanisms such as environmental filtering may favor the recruitment of savanna trees over forest trees (chapter 4).

In chapter 5, I experimentally tested in the field the roles of dispersal limitation, and environmental filtering for tree recruitment in burnt floodplain forests. I combine inventories of seed availability in burnt sites with experiments using planted seeds and seedlings of six floodplain tree species. Repeated fires strongly reduce the availability of tree seeds, yet planted trees thrive despite degraded soils and high herbaceous cover. Moreover, degraded soils on twice burnt sites seem to limit the growth of most pioneer trees, but not of savanna trees with deeper roots. Our results suggest a limitation of forest trees to disperse into open burnt sites.

The combined evidence presented in this thesis support the hypothesis that Amazonian forests on floodplains are less resilient than forests on uplands, and more likely to shift into a savanna state. The lower ability of floodplains to retain soil fertility and recover forest structure after fire, may accelerate the transition to savanna. I also present some evidence of dispersal limitation of floodplain forest trees. Broad-scale analyses of tree cover as a function of rainfall suggest that savannas are likely to expand first in floodplains if Amazonian climate becomes drier. Savanna expansion through floodplain ecosystems to the core of the Amazon may spread fragility from an unsuspected place.

Tools voor klimaatbestendig inrichten van stedelijk gebied
Ven, Frans van der; Brolsma, R. ; Snep, R.P.H. ; Koole, S. - \ 2016
H2O online (2016)29 maart. - 7 p.
stedelijke gebieden - ruimtelijke ordening - waterbeheer - overstromingen - stedelijke planning - klimaatverandering - klimaatadaptatie - urban areas - physical planning - water management - floods - urban planning - climatic change - climate adaptation
Er zijn tools ontwikkeld waarmee ontwerpers, deskundigen en belanghebbenden samen conceptuele ontwerpen kunnen opstellen om te helpen de gebouwde omgeving waterrobuust en klimaatbestendig te maken. De Climate Adaptation App helpt deelnemers een long list van mogelijke maatregelen op te stellen. Vervolgens kan met de Adaptation Support Tool worden geschetst waar welke maatregelen getroffen kunnen worden en wordt direct berekend hoe doelmatig ze naar verwachting zullen zijn (rekenen en tekenen). Water- en klimaatopgaven worden op (kosten)effectieve wijze ingevuld en de toegevoegde waarde van ingrepen voor de leefbaarheid gemaximaliseerd. Deze werkwijze en tools zijn met succes toegepast in diverse ontwerpworkshops.
Wat te doen tegen de toename van overstromingsrisico's in de toekomst? : handelingsperspectieven voor beleid en beheer afgeleid uit het onderzoek naar toekomstbestendige overstromingsrisicobeheersing van Kennis voor Klimaat
Klijn, F. ; Maarse, M. ; Kok, M. ; Loon-Steensma, J.M. van; Moel, H. de; Mulder, J. - \ 2015
Amersfoort : Stowa (STOWA-rapportnummer 2015-33) - ISBN 9789057737213 - 123
klimaatverandering - klimaatadaptatie - overstromingen - overstromingstolerantie - hoogwaterbeheersing - waterbeheer - risicovermindering - nederland - climatic change - climate adaptation - floods - flooding tolerance - flood control - water management - risk reduction - netherlands
Het klimaat verandert en de zeespiegel stijgt. Daarover bestaat geen twijfel, hoewel er nog wel onzekerheid bestaat over de snelheid van de veranderingen, en soms over de precieze richting daarvan. Ondanks deze onzekerheden is het verstandig te anticiperen op wat komen gaat. Daar zijn we in Nederland dan ook al volop mee bezig. In de afgelopen jaren is in diverse projecten en programma’s zoals Kennis voor Klimaat, het Deltaprogramma en STOWA/Deltaproof, veel kennis opgedaan over mogelijke strategieën om ons aan te passen aan de veranderende klimatologische omstandigheden. Maar hoe zien dergelijke adaptatiestrategieën er precies uit en hoe kom je tot een concrete invulling? Dit rapport geeft een overzicht van concrete maatregelen die kunnen worden ingezet bij adaptatie in verband met de toenemende overstromingsrisico’s. Het rapport richt zich vooral op wat gemeenten, provincies en waterschappen kunnen doen.
Climate change, uncertainty and investment in flood risk reduction
Pol, T.D. van der - \ 2015
Wageningen University. Promotor(en): Ekko van Ierland, co-promotor(en): Hans-Peter Weikard; Silke Gabbert; Eligius Hendrix. - Wageningen : Wageningen University - ISBN 9789462574373 - 147
klimaatverandering - hoogwaterbeheersing - overstromingen - risicovermindering - waterbeheer - economische analyse - economische modellen - investering - climatic change - flood control - floods - risk reduction - water management - economic analysis - economic models - investment

Economic analysis of flood risk management strategies has become more complex due to climate change. This thesis investigates the impact of climate change on investment in flood risk reduction, and applies optimisation methods to support identification of optimal flood risk management strategies. Chapter 2 provides an overview of cost-benefit analysis (CBA) of flood risk management strategies under climate change uncertainty and new information. CBA is applied to determine optimal dike heights under climate change uncertainty and new information in Chapter 3. Chapter 4 studies impacts of rainfall variability and changing return periods of rainfall extremes on cost-effective adaptation of water systems to climate change given a flood protection standard. Chapter 5 departs from expected cost minimisation, and applies the minimax regret decision criterion to identify maximum regret minimising flood risk management strategies under the arrival of new climate impact information. The thesis concludes that the modelling of new climate-related information may improve an economic analysis of flood risk management strategies

A review of damage-reducing measures to manage fluvial flood risks in a changing climate
Kreibich, H. ; Bubeck, Ph. ; Vliet, M. van; Moel, H. de - \ 2015
Mitigation and Adaptation Strategies for Global Change 20 (2015)6. - ISSN 1381-2386 - p. 967 - 989.
klimaatverandering - landgebruiksplanning - overstromingen - risicobeheersing - ontwikkelingslanden - climatic change - land use planning - floods - risk management - developing countries
Damage due to floods has increased during the last few decades, and further increases are expected in several regions due to climate change and growing vulnerability. To address the projected increase in flood risk, a combination of structural and non-structural flood risk mitigation measures is considered as a promising adaptation strategy. Such a combination takes into account that flood defence systems may fail, and prepares for unexpected crisis situations via land-use planning and private damage reduction, e.g. via building precautionary measures, and disaster response. However, knowledge about damage-reducing measures is scarce and often fragmented since based on case studies. For instance, it is believed that private precautionary measures, like shielding with water shutters or building fortification, are especially effective in areas with frequent flood events and low flood water levels. However, some of these measures showed a significant damage-reducing effect also during the extreme flood event in 2002 in Germany. This review analyses potentials of land-use planning and private flood precautionary measures as components of adaptation strategies for global change. Focus is on their implementation, their damage-reducing effects and their potential contribution to address projected changes in flood risk, particularly in developed countries.
Launching the Delta Alliance: business development report phase 3
Driel, W.F. van; Peters, R. ; Guchte, C. van de - \ 2014
Wageningen : Delta Alliance - 23
klimaatverandering - overstromingen - kustgebieden - delta's - azië - afrika - amerika - europa - climatic change - floods - coastal areas - deltas - asia - africa - america - europe
Delta Alliance is an international knowledge-driven network organisation. Its mission is to improve the resilience of deltas through more integrated and effective efforts, building on scientific research and knowledge exchange. It aims at disclosure of knowledge for application by a wide audience of end-users from the knowledge institutions, public partners and private sector, as well as to identification of upcoming research agendas
Ten building blocks for sustainable water governance: an integrated method to assess the governance of water
Rijswick, M. ; Edelenbos, J. ; Hellegers, P.J.G.J. ; Kok, M. ; Kuks, S.M.M. - \ 2014
Water International 39 (2014)5. - ISSN 0250-8060 - p. 725 - 742.
watersystemen - waterbeheer - oppervlaktewaterkwaliteit - overstromingen - risicoschatting - infrastructuur - governance - watervoorraden - beoordeling - hoogwaterbeheersing - water systems - water management - surface water quality - floods - risk assessment - infrastructure - water resources - assessment - flood control - research agenda - management - climate
A three-step interdisciplinary method to assess approaches to water shortage, water quality and flood risks is presented. This method, based on water system analysis, economics, law and public administration, seeks to create common understanding based on newly developed concepts and definitions. First, generating content knowledge about the water system and about values, principles and policy discourses. Second, providing an organizational process with sufficient stakeholder involvement, insight into the trade-off between social objectives, and attribution of responsibilities in addition to regulations and agreements. Finally, implementing the agreed service level through adequate infrastructure, enforcement and conflict resolution.
Sedimentatiemodel kwelders Ameland Fase 1: ontwerp en haalbaarheid
Groot, A.V. de; Duin, W.E. van; Brinkman, A.G. ; Vries, P. de - \ 2014
Den Helder : IMARES (Rapport / IMARES Wageningen UR C025/14) - 47
kweldergronden - waterstand - bodemdaling - aardgas - overstromingen - risicoschatting - fauna - watervogels - nederlandse waddeneilanden - salt marsh soils - water level - subsidence - natural gas - floods - risk assessment - waterfowl - dutch wadden islands
Op Ameland vindt bodemdaling plaats als gevolg van gaswinning. Dit heeft consequenties voor de opslibbingsbalans en daarmee de maaiveldhoogte van de oostelijke kwelders Neerlands Reid en De Hon, vergeleken met wanneer er geen bodemdaling zou hebben plaatsgevonden. Dit kan weer gevolgen hebben voor het broedsucces van grondbroedende vogels, dat mede afhankelijk is van het overstromingsrisico. Om de impact van gaswinning op het ecosysteem te bepalen, is het dus mede van belang om inzicht te krijgen in hoe het overstromingsrisico op de kwelders op Ameland zou zijn geweest vanaf 1986 zónder de opgetreden bodemdaling. Daarvoor is het nodig de hoogteligging zonder bodemdaling te reconstrueren.
Launching the Delta Alliance: Content report phase 3
Bosch, R. van den; Bucx, T. ; Klostermann, J.E.M. ; Wijsman, P. ; Driel, W.F. van; Guchte, C. van de - \ 2014
Wageningen : Delta Alliance - 23
klimaatverandering - overstromingen - kustgebieden - delta's - azië - afrika - amerika - europa - climatic change - floods - coastal areas - deltas - asia - africa - america - europe
Delta Alliance is an international knowledge-driven network organisation. Its mission is to improve the resilience of deltas through more integrated and effective efforts, building on scientific research and knowledge exchange. It aims at disclosure of knowledge for application by a wide audience of end-users from the knowledge institutions, public partners and private sector, as well as to identification of upcoming research agendas
Klimaat en waterbeheer: als het water komt
Klostermann, Judith - \ 2014
water management - floods - governance - climatic change
You Have Been Framed! How Antecedents of Information Need Mediate the Effects of Risk Communication Messages
Terpstra, T. ; Zaalberg, R. ; Boer, J. de; Botzen, W.J.W. - \ 2014
Risk Analysis 34 (2014)8. - ISSN 0272-4332 - p. 1506 - 1520.
klimaatverandering - overstromingen - risicoanalyse - burgers - informatiebehoeften - climatic change - floods - risk analysis - citizens - information needs - attitude-change - perceived risk - seeking model - fear appeals - flood risks - pre model - trust - preparedness - perception - emotions
This study investigates the processes that mediate the effects of framing flood risks on people's information needs. Insight into the effects of risk frames is important for developing balanced risk communication that explains both risks and benefits of living near water. The research was inspired by the risk information seeking and processing model and related models. In a web-based survey, respondents (n = 1,457) were randomly assigned to one of three communication frames or a control frame (experimental conditions). Each frame identically explained flood risk and additionally refined the message by emphasizing climate change, the quality of flood risk management, or the amenities of living near water. We tested the extent to which risk perceptions, trust, and affective responses mediate the framing effects on information need. As expected, the frames on average resulted in higher information need than the control frame. Attempts to lower fear appeal by stressing safety or amenities instead of climate change were marginally successful, a phenomenon that is known as a “negativity bias.” Framing effects were mediated by negative attributes (risk perception and negative affect) but not by positive attributes (trust and positive affect). This finding calls for theoretical refinement. Practically, communication messages will be more effective when they stimulate risk perceptions and evoke negative affect. However, arousal of fear may have unwanted side effects. For instance, fear arousal could lead to lower levels of trust in risk management among citizens. Regular monitoring of citizens’ attitudes is important to prevent extreme levels of distrust or cynicism.
River flood damage estimation in Jakarta, Indonesia
Wijayanti, P. ; Zhu, X. ; Hellegers, P.J.G.J. ; Budiyono, Y. ; Ierland, E.C. van - \ 2014
klimaatadaptatie - klimaatverandering - overstromingen - kustgebieden - indonesië - climate adaptation - climatic change - floods - coastal areas - indonesia
Flooding is a serious problem in Jakarta. Estimation of flood damages is important to estimate the benefits of implementing flood protection measures.
Improving operational flood forecasting using data assimilation
Rakovec, O. - \ 2014
Wageningen University. Promotor(en): Remko Uijlenhoet, co-promotor(en): Albrecht Weerts. - Wageningen : Wageningen University - ISBN 9789461738493
overstromingen - hoogwaterbeheersing - voorspellen - data-assimilatie - gegevensanalyse - hydrologie - modellen - floods - flood control - forecasting - data assimilation - data analysis - hydrology - models
Hoogwatervoorspellingssystemen die betrouwbaar en nauwkeurig overstromingen kunnen voorspellen zijn erg belangrijk, omdat dit het aantal slachtoffers en de economische schade van overstromingen kan beperken. Het begrijpen van het gedrag van extreme hydrologische gebeurtenissen en het vermogen van de modelleur om betere en nauwkeurigere prognoses te krijgen, zijn uitdagingen binnen de toegepaste hydrologie. Omdat modellen slechts een versimpelde weergave van de complexe werkelijkheid geven, kleven er aan hydrologische voorspellingen veel onzekerheden. Dit proefschrift draagt bij aan een verbeterd begrip en kwantificatie van hydrologische modelonzekerheid, vooral gekoppeld aan de initi¨ele condities van het model, en in mindere mate aan de modelstructuur en de parameters.
Including climate change projections in probabilistic flood risk assessment
Ward, P.J. ; Pelt, S.C. van; Keizer, O. de; Aerts, J.C.J.H. ; Beersma, J.J. ; Hurk, B.J.J.M. van den - \ 2014
Journal of Flood Risk Management 7 (2014)2. - ISSN 1753-318X - p. 141 - 151.
klimaatverandering - overstromingen - risicoschatting - modellen - climatic change - floods - risk assessment - models - rhine basin - model - precipitation - uncertainty - simulations - decisions
This paper demonstrates a framework for producing probabilistic flood risk estimates, focusing on two sections of the Rhine River. We used an ensemble of six (bias-corrected) regional climate model (RCM) future simulations to create a 3000-year time-series through resampling. This was complemented with 12 global climate model (GCM)-based future time-series, constructed by resampling observed time-series of daily precipitation and temperature and modifying these to represent future climate conditions using an advanced delta change approach. We used the resampled time-series as input in the hydrological model Hydrologiska Byråns Vattenbalansavdelning (HBV)-96 to simulate daily discharge and extreme discharge quantiles for return periods up to 3000 years. To convert extreme discharges to estimates of flood damage and risk, we coupled a simple inundation model with a damage model. We then fitted probability density functions (PDFs) for the RCM, GCM, and combined ensembles. The framework allows for the assessment of the probability distribution of flood risk under future climate scenario conditions. Because this paper represents a demonstration of a methodological framework, the absolute figures should not be used in decision making at this time.
Evaluating the effect of flood damage-reducing measures: a case study of the unembanked area of Rotterdam, the Netherlands
Moel, H. de; Vliet, M. van; Aerts, J.C.J.H. - \ 2014
Regional Environmental Change 14 (2014)3. - ISSN 1436-3798 - p. 895 - 908.
overstromingen - hoogwaterbeheersing - schade - risicovermindering - risicobeheersing - klimaatverandering - rotterdam - stedelijke gebieden - floods - flood control - damage - risk reduction - risk management - climatic change - urban areas - model - uncertainty - households - insurance - sector - meuse
Empirical evidence of increasing flood damages and the prospect of climatic change has initiated discussions in the flood management community on how to effectively manage flood risks. In the Netherlands, the framework of multi-layer safety (MLS) has been introduced to support this risk-based approach. The MLS framework consists of three layers: (i) prevention, (ii) spatial planning and (iii) evacuation. This paper presents a methodology to evaluate measures in the second layer, such as wet proofing, dry proofing or elevating buildings. The methodology uses detailed land-use data for the area around the city of Rotterdam (up to building level) that has recently become available. The vulnerability of these detailed land-use classes to flooding is assessed using the stage–damage curves from different international models. The methodology is demonstrated using a case study in the unembanked area of Rotterdam in the Netherlands, as measures from the second layer may be particularly effective there. The results show that the flood risk in the region is considerable: EUR 36 million p.a. A large part (almost 60 %) of this risk results from industrial land use, emphasising the need to give this category more attention in flood risk assessments. It was found that building level measures could substantially reduce flood risks in the region because of the relatively low inundation levels of buildings. Risk to residential buildings would be reduced by 40 % if all buildings would be wet-proofed, by 89 % if all buildings would be dry-proofed and elevating buildings over 100 cm would render the risk almost zero. While climate change could double the risk in 2100, such building level measures could easily nullify this effect. Despite the high potential of such measures, actual implementation is still limited. This is partly caused by the lack of knowledge regarding these measures by most Dutch companies and the legal impossibility for municipalities to enforce most of these measures as they would go beyond the building codes established at the national level.
Netwerk Land en Water ‘Nieuwe wegen in de hydrologie’
Breugem, A. ; Knotters, M. - \ 2013
Stromingen : vakblad voor hydrologen 19 (2013)1. - ISSN 1382-6069 - p. 63 - 67.
hydrologie - monitoring - neerslag - stedelijke gebieden - gegevensverwerking - overstromingen - hoogwaterbeheersing - watergebruik - conferenties - hydrology - precipitation - urban areas - data processing - floods - flood control - water use - conferences
Op woensdag 20 juni 2012 belegde het Netwerk Land en Water een studiemiddag over het thema ‘Nieuwe wegen in de hydrologie’. Dit thema is ingegeven vanuit de verwachting dat door klimaatverandering extreme neerslaggebeurtenissen frequenter zullen optreden, wat kan leiden tot grote wateroverlast. Om voor deze gebeurtenissen adequate oplossingen te vinden zijn nieuwe wegen in de hydrologie noodzakelijk, zowel in de wetenschap als in de aan het beleid gekoppelde praktijk. Op deze middag werden in drie lezingen enkele wetenschappelijke ontwikkelingen in de hydrologie voor het voetlicht gebracht: - Stedelijke neerslagmetingen, door Marie-Claire ten Veldhuis (TuD); - Extreme neerslag en afvoerprocessen in het stroomgebied van de Hupselse Beek, door Claudia Brauer (WUR); - Operationele monitoring van hydrologische processen op verschillende schalen, door Henk Pelgrum van eLEAF
Deltascenario’s voor 2050 en 2100 : nadere uitwerking 2012-2013
Bruggemann, W. ; Dammers, E. ; Born, G.J. van den; Rijkens, B. ; Bemmel, B. van; Bouwman, A. ; Nabielek, K. ; Beersma, J. ; Hurk, B. van den; Polman, N.B.P. ; Linderhof, V.G.M. ; Folmer, C. ; Huizinga, F. ; Hommes, S. ; Linde, A. te; Didde, R. ; Roukema, M. - \ 2013
Delft : Deltares - 65
klimaatverandering - economische groei - economische ontwikkeling - scenario-analyse - overstromingen - risicoanalyse - climatic change - economic growth - economic development - scenario analysis - floods - risk analysis
Planbureau voor de Leefomgeving (PBL), Centraal Planbureau (CPB), KNMI en Wageningen UR, LEI publiceren onder leiding van Deltares de ‘Deltascenario’s voor 2050 en 2100 – nadere uitwerking 2012-2013’. Deze scenario’s bouwen voort op de in 2011 gepubliceerde Deltascenario’s. Ze zijn gebaseerd op meer óf minder economische groei in combinatie met matige óf grote klimaatverandering. De vier scenario’s hebben de namen: RUST (resultaat van matige klimaatverandering en lage groei van economie en bevolking); DRUK (matige klimaatverandering, sterke groei); WARM (snelle klimaatverandering, lage groei); STOOM (snelle klimaatverandering, sterke groei). Aan de hand van elk van de uitgewerkte scenario’s toont het consortium voor welke uitdagingen Nederland in de toekomst kan komen te staan als het gaat om zoetwatervoorziening, de ruimtelijke inrichting van stad en land en bescherming tegen overstromingen.
Runoff, discharge and flood occurrence in a poorly gauged tropical basin : the Mahakam River, Kalimantan
Hidayat, H. - \ 2013
Wageningen University. Promotor(en): Remko Uijlenhoet, co-promotor(en): Ton Hoitink. - S.l. : s.n. - ISBN 9789461737434 - 114
oppervlakkige afvoer - afvoer - overstromingen - monitoring - tropen - modellen - rivieren - cartografie - voorspelling - kalimantan - indonesië - runoff - discharge - floods - tropics - models - rivers - mapping - prediction - indonesia

Tidal rivers and lowland wetlands present a transition region where the interests of hydrologists and physical oceanographers overlap. Physical oceanographers tend to simplify river hydrology, by often assuming a constant river discharge when studying estuarine dynamics. Hydrologists, in turn, generally ignore the direct or indirect effects of tides in water level and discharge records. This thesis aims to improve methods to monitor, model and predict discharge dynamics in tidal rivers and lowland wetlands, by focussing on the central and lower reaches of the River Mahakam (East Kalimantan, Indonesia), and the surrounding lakes area. The 980-km long river drains an area of about 77100 km2 between 2°N - 1°S and 113°E - 118°E. Due to its very mild bottom slope, a significant tidal influence occurs in this river. The middle reach of the river is located in a subsiding basin, parts of which are below mean sealevel, featuring peat swamps and about thirty lakes connected to the river via tie channels.

Upstream of the lakes area, at about 300 km from the river mouth, an acoustic Doppler current profiler (H-ADCP) has been horizontally deployed at a station near the city of Melak (Chapter 2). The H-ADCP profiles of velocity are converted to discharge adopting a new calibration methodology. The obtained time-series of discharge show the tidal signal is clearly visible during low flow conditions. Besides tidal signatures, the discharge series show influences by variable backwater effects from the lakes, tributaries and floodplain ponds. The discharge rate at the station exceeds 3250 m3s-1 with a hysteretic behaviour. For a specific river stage, the discharge range can be as high as 2000 m3s-1. Analysis of alternative types of rating curves shows this is far beyond what can be explained from kinematic wave dynamics. Apart from backwater effects, the large variation of discharge for a specified river stage can be explained by river-tide interaction, impacting discharge variation especially in the fortnightly frequency band.

A second H-ADCP station has been setup in the lower reach of the Mahakam, near the city of Samarinda, where the tidal discharge amplitude generally exceeds the discharge related to runoff (Chapter 3). Conventional rating curve techniques are inappropriate to model river discharge at this tidally influenced station. As an alternative, an artificial neural network (ANN) model is developed to investigate the degree to which tidal river discharge at Samarinda station can be predicted from an array of level gauge measurements along the tidal river, and from tidal level predictions at sea. The ANN-based model produces a good discharge estimation, as established from a consistent performance during both the training and the validation periods, showing the discharges can be predicted from water levels only, once that a trained model is available. The ANN models perform well in predicting discharges up to two days in advance.

Chapter 4 addresses the role of backwater effects and tidal influences on discharge time-series used to calibrate a rainfall-runoff model. The HBV rainfall-runoff model is implemented for the Mahakam sub-catchment upstream of Melak (25700 km2). In a first approach, the model is calibrated using a discharge series derived from the H-ADCP measurements from Melak station. In a second approach, discharge estimates derived from a rating curve are used to calibrate the model. Adopting the first approach, a comparatively low model efficiency is obtained, which is attributed to the backwater and tidal effects that are not captured in the model. The second approach produces a relatively higher model efficiency, since the rating curve filters the backwater effects out of the discharge series. Seasonal variation of terms in the water balance is not affected by the choice for one of the two calibration strategies, which shows that backwaters do not have a systematic seasonal effect on the river discharge.

To allow for investigation of the causes of backwater effects, satellite radar remote sensing is employed to monitor water levels in wetlands (Chapter 5). A series of Phased Array L-band Synthetic Aperture Radar (PALSAR) images is used to observe the dynamics of the Mahakam River floodplain. To analyze radar backscatter behavior for different land cover types, several regions of interest are selected, based on land cover classes. Medium shrub, high shrub, fern/grass, and degraded forest are found to be sensitive to flooding, whereas peat forest, riverine forest and tree plantation backscatter signatures only slightly change with flood inundation. An analysis of the relationship between radar backscatter and water levels is carried out. For lakes and shrub covered peatland, for which the range of water level variation is high, a good water level-backscatter correlation is obtained. In peat forest covered peatland, subject to a small range of water level variation, water level-backscatter correlations are poor, limiting the ability to obtain a floodplain-wide water surface topography from the radar images.

Chapter 6 continues to investigate the degree in which satellite radar remote sensing can serve to distinguish between dry areas and wetlands, which is a difficult task in densely vegetated areas such as peat domes. Flood extent and flood occurrence information are successfully extracted from a series of radar images of the middle Mahakam lowland area. A fully inundated region is easily recognized from a dark signature on radar images. Open water flood occurrence is mapped using a threshold value taken from radar backscatter of the permanently inundated areas. Radar backscatter intensity analysis of the vegetated floodplain area reveals consistently higher backscatter values, indicating flood inundation under forest canopy. Those observations are used to establish thresholds for flood occurrence mapping in the vegetated area. An all-encompassing flood occurrence map is obtained by combining the flood occurrence maps for areas with and without vegetation.

Chapter 7 synthesizes the findings from the previous chapters. It is concluded that the backwater effects and subtle tidal influences may prevent the option to predict river discharge using rating curves, which can best be interpreted as a stage-runoff relationship. H-ADCPs offer a promising alternative to monitor river discharge. For a tidal river, an ANN model can be used as a tool for data gap filling in an H-ADCP based discharge series, or even to derive discharge estimates solely from water levels and water level predictions. Discharge can be predicted several time-steps ahead, allowing water managers to take measures based on forecasts. The stage-runoff relationship derived from a continuous series of H-ADCP based discharge estimates may be expected to be much more accurate than a similar rating curve derived from a small number of boat surveys. The flood occurrence map derived from PALSAR images can offer a detailed insight into the hydroperiod, the period in which a soil area is waterlogged, and flood extent of the lowland area, illustrating the added value of radar remote sensing to wetland hydrological studies. In future work, radar-based floodplain observations may serve to calibrate hydrodynamic models simulating the processes of flooding and emptying of the lakes area.

Adaptief vermogen van bedrijven in buitendijks gebied : inventarisatie van strategieën voor hoog water bij buitendijks gevestigde bedrijven in het Waddengebied
Klostermann, J.E.M. ; Koperberg, Y. ; Smale, A. ; Slager, K. - \ 2013
Wageningen : Alterra, Wageningen-UR (Alterra-report 2444) - 154
hoogwaterbeheersing - overstromingen - klimaatverandering - bedrijventerreinen - havens - veiligheid - risicobeheersing - groningen - friesland - waddenzee - flood control - floods - climatic change - business parks - harbours - safety - risk management - wadden sea
Buitendijks gevestigde bedrijven zijn zelf verantwoordelijk voor hun veiligheid en het voorkomen van schade door een overstroming. Door klimaatverandering kan de kans op een overstroming toenemen. Daarom is in opdracht van het Deltaprogramma Waddengebied onderzoek gedaan naar de ‘vulnerability’ en ‘adaptive capacity’ van buitendijks gevestigde bedrijven. Het betreft de havens van Delfzijl, Eemshaven en Den Helder. En de veerdam Holwerd, Nes en Ballumerbocht (Ameland). In dit onderzoek is aan de bedrijven gevraagd welke strategieën ze hebben om met overstromingen om te gaan. Ook is gekeken naar de rol van de overheid en is geprobeerd de potentiële schade in buitendijkse gebieden te berekenen. Er is geen reden voor paniek. Alleen in zeer extreme gevallen zullen de buitendijkse gebieden overstromen, en in die gevallen kunnen bedrijven het zien aankomen. Bovendien beschikken veel bedrijven in de haven zelf over de middelen om te handelen in geval van een overstroming. Daarvoor is wel een betere bewustwording noodzakelijk en betere informatie. Met name in de informatievoorziening hebben de overheden een rol; ook al zijn buitendijkse bedrijven formeel zelf verantwoordelijk voor hun veiligheid. De bedrijven zelf zouden geen overstroming moeten afwachten voordat ze over dit risico gaan nadenken. Preventie is vrijwel altijd goedkoper dan de schade die een (onverwachte) overstroming oplevert.
Schadeberekening graslandinundatie op melkveebedrijven = Damage calculation grassland floods on dairy farms
Hoving, I.E. ; Boer, J.A. de; Kanis, J. - \ 2013
Lelystad : Wageningen UR Livestock Research (Rapport / Wageningen UR Livestock Research 700) - 30
melkveehouderij - melkveebedrijven - graslanden - overstromingen - schade - zandgronden - inundatie - dairy farming - dairy farms - grasslands - floods - damage - sandy soils - flooding
The Flooding Damage Indicator calculates the damage by grassland flooding on dairy farms located on sandy soils. The foundation of the program is a comprehensive database of technical and financial data, based on a large number of dairy farm calculated estimates.
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