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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    De Wageningen Lowland Runoff Simulator (WALRUS): een snel neerslag-afvoermodel speciaal voor laaglandstroomgebieden
    Brauer, C.C. ; Torfs, P.J.J.F. ; Teuling, A.J. ; Uijlenhoet, R. - \ 2016
    Stromingen : vakblad voor hydrologen 22 (2016)1. - ISSN 1382-6069 - p. 7 - 18.
    neerslag - hydrologie van stroomgebieden - modellen - afvoerwater - laaglandgebieden - stroomgebieden - grondwater - oppervlaktewater - kwel - reservoirs - droogte - risicoanalyse - precipitation - catchment hydrology - models - effluents - lowland areas - watersheds - groundwater - surface water - seepage - reservoirs - drought - risk analysis
    De Wageningen Lowland Runoff Simulator (WALRUS) is een nieuw neerslag-afvoermodel dat het gat moet vullen tussen complexe, ruimtelijk gedistribueerde modellen die vaak gebruikt worden in laaglandstroomgebieden en simpele, ruimtelijk geïntegreerde, parametrische modellen die voornamelijk zijn ontwikkeld voor hellende stroomgebieden. WALRUS houdt expliciet rekening met hydrologische processen die belangrijk zijn in laaglandgebieden, in het bijzonder (1) de koppeling tussen grondwater en onverzadigde zone, (2) vochttoestandafhankelijke stroomroutes, (3) grondwater-oppervlaktewaterterugkoppeling en (4) kwel, wegzijging en het inlaten of wegpompen van oppervlaktewater. WALRUS bestaat uit een gekoppeld reservoir voor grondwater en onverzadigde zone, een reservoir voor snelle stroomroutes en een oppervlaktewaterreservoir. Het is geschikt voor operationele toepassingen omdat het efficiënt rekent en numeriek stabiel is. In de vrij toegankelijke modelcode zijn standaardrelaties geïmplementeerd, zodat er slechts vier parameters overblijven die gekalibreerd hoeven te worden. Het model is geschikt voor het operationeel simuleren van hoogwater en droogte ten behoeve van risico-analyses en scenario-analyses, voor het ontwerpen van infrastructuur en voor het aanvullen van ontbrekende gegevens in afvoermeetreeksen
    Optimizing soil and water management in dryland farming systems in Cabo Verde
    Santos Baptista Costa, I. Dos - \ 2016
    Wageningen University. Promotor(en): Coen Ritsema; Violette Geissen, co-promotor(en): Luuk Fleskens. - Wageningen : Wageningen University - ISBN 9789462577367 - 189
    water management - soil management - farming systems - dry farming - optimization - watershed management - watersheds - runoff - erosion control - cape verde - waterbeheer - bodembeheer - bedrijfssystemen - dry farming - optimalisatie - beheer van waterbekkens - stroomgebieden - oppervlakkige afvoer - erosiebestrijding - kaapverdië
    Soil and land degradation poses a great challenge for sustainable development worldwide and, in Cabo Verde, has strongly affected both people’s livelihood and the environment. Dryland food production in Cabo Verde faces steep slopes, inadequate practices, irregular intense rain, recurrent droughts, high runoff rates, severe soil erosion and declining soil fertility, leading to the inefficient use of rainwater. Despite the enormous investment in soil and water conservation measures (SWC), land degradation due to water erosion is still rife and dryland crop productivity remains low. Sustainable land management (SLM) techniques that reduce runoff, erosion and nutrient loss are the key to mitigating/preventing land degradation and assuring long-term soil productivity.

    This thesis investigated soil and water management techniques for Cabo-Verdean dryland farming systems to increase the efficiency of rainwater and crop yield, combining traditional and scientific knowledge in a field-based participatory approach. Field experiments were conducted in different agro-ecological zones of the Santiago Island aiming to evaluate the effects of water conservation techniques (mulching of crop residue, soil surfactant and pigeon-pea hedges) combined with organic amendments (compost and animal or green manure) on runoff, erosion, soil nutrients and crop yield. The PESERA-DESMICE modelling approach allowed assessing the biophysical and socio-economic benefits of the promising SLM techniques against a local baseline condition and their potential application at larger scale, under climate variability.

    Following the general introduction (chapter 1), chapter 2 of the thesis reviews the national strategies towards building resilience against the harsh environmental conditions, analyses the state of land degradation and its drivers, surveys the existing SWC measures, and assesses their effectiveness against land degradation and in supporting people’s livelihoods. The analysis allows inferring that the relative success of Cabo Verde in tackling desertification and rural poverty is due to an integrated governance strategy that comprises awareness raising, institutional framework development, financial resource allocation, capacity building, and active participation of rural communities. The chapter provides a panoramic view of the importance of SWC measures for Cabo Verde drylands and recommends further specific, science-based assessment of the biophysical and socioeconomic impact of SLM and potential for upscaling.

    Chapter 3, first, discusses the participatory approach used in selecting the SLM techniques that are field-tested in this research and, then, evaluates the effects of the selected water conservation techniques combined with organic amendments on the generation of runoff and soil loss from rain-fed agricultural fields compared with traditional farmers’ practices. The chapter also discusses the main factors influencing runoff and soil loss in semiarid dryland hilly areas, including the degree of soil cover, rainfall amount and erosivity, slope and soil infiltration rate. Runoff was significantly reduced only with the treatments containing mulch on slopes >10% and in the treatment containing surfactant and organic amendment on slopes <10%. Observed soil erosion rates were highest for the silty-clay-loam soil, followed by the sandy-loam soil and the loamy-soil, reaching a maximum value of 17 Mg ha-1 in the traditional practice, but were reduced by more than 50% with the SLM techniques. Residue mulch and pigeon-pea combined with an organic amendment (T3) almost eliminated runoff and erosion from agricultural fields even on steep slopes, contributing to improved use of rainwater at the plot level. The chapter recommends that SLM techniques, such as T3, be advocated and promoted for the semiarid hillsides of Cabo Verde prone to erosion to increase rainwater-use and to prevent further soil degradation.

    As soil erosion, runoff and related nutrient losses constitute a high risk to soil fertility in Cabo Verde drylands, chapter 4 focuses on the effects of the techniques tested in chapter 3 on erosion and runoff related nutrient losses (NO3-N and PO4-P) and on crop productivity. The traditional system lost significantly higher amounts of both NO3-N and PO4-P than the tested SLM techniques, with the T3 technology reducing soil loss, runoff and nutrient losses to nearly a 100%. Nutrient losses from the amended plots were low, while the significant losses from the traditional system could result in long-term nutrient depletion in the soil. The treatments did not consistently increase crop yield or biomass in all three sites, but the combination of organic amendment with soil surfactant increased both crop yield and biomass in some cases. T3 was the best treatment for steep slope areas, although it is crucial to manage the pigeon-pea hedges to achieve higher maize yield. For flatter areas with deeper soils, the combination of organic amendment with soil surfactant could be a less expensive and effective choice. The chapter identifies and recommends SLM techniques to prevent nutrient depletion, improve dryland crop yield and avoid further land degradation due to erosion by water, both in steep slope areas and flatter areas.

    Given the potential of the SLM techniques, but also significant spatial-temporal yield variability, chapter 5 considers the PESERA-DESMICE modelling approach to capture a greater range of climatic conditions and evaluate the biophysical and socio-economic benefits of the promising SLM technique (residue mulch combined with pigeon-pea hedges and an organic amendment - T3) against the traditional baseline practice of maize-bean intercropping (T0). It also evaluates the potential for upscaling the selected technique at Island scale. From stations in semi-arid and sub humid climates, long-term historic rainfall statistics allowed construction of 50-year rainfall realizations providing a unique time-series of rainfall scenarios and an envelope of the potential biomass production. T3 elevates yield under both sub-humid and semi-arid climates with greater security for sub-humid areas even though risk of crop failure still exists. The T3 technology offered good potential to increase yields by 20% in 42% of the area and reduce erosion by 8.6 Mg ha-1, but in terms of cost effectiveness, it might be prohibitively expensive for farmers lacking inputs. Such findings can inform policy options or influence adoption of conservation measures under the climatic variability of the Cabo Verde drylands and resilience to future climate change.

    The thesis ends with a synthesis chapter (6) that presents the research findings, highlights the new contributions made to the current scientific debates on Climate-Smart Agriculture (CSA) technologies for sub-Saharan Africa, sustainable intensification and land degradation neutrality. The T3 technology can be a promising CSA practice that could be widely used by smallholder farmers in semiarid regions to maintain food production and secure farmers’ livelihoods, while contributing to ecosystem services by storing water in the soil. The synthesis concludes with policy recommendations for optimizing soil and water management on hilly drylands to prevent further degradation.

    Hence, the thesis presents options to support moving from degrading and low yielding land management practices towards more sustainable land intensification in hilly drylands that reduce runoff and soil loss, increase crop nutrient and crop productivity, ultimately, contributing to the mitigation/adaptation of climate change, food security and land degradation neutrality in Cabo Verde.

    Waterkwaliteit nu en in de toekomst : Eindrapport ex ante evaluatie van de Nederlandse plannen voor de Kaderrichtlijn Water : beleidsstudie
    Gaalen, F. van; Tiktak, A. ; Franken, Ron ; Boekel, E.M.P.M. van; Puijenbroek, P. ; Muilwijk, Hanneke ; Grinsven, H. van; Rougoor, C. ; Salm, C. van der; Groenendijk, P. ; Cleij, P. ; Roovaart, Joost van den - \ 2016
    Planbureau voor de Leefomgeving (PBL-publicatie / Planbureau voor de Leefomgeving 1727) - 54
    waterkwaliteit - kaderrichtlijn water - oppervlaktewater - oppervlaktewaterkwaliteit - waterbeheer - pesticiden - stroomgebieden - water quality - water framework directive - surface water - surface water quality - water management - pesticides - watersheds
    De Nederlandse stroomgebiedbeheerplannen voor de periode 2016-2021 zijn in december 2015 vastgesteld. Het PBL heeft op verzoek van het ministerie van Infrastructuur en Milieu (IenM) op basis van metingen en modelberekeningen geëvalueerd of de voorgestelde maatregelen in de plannen en het vijfde nitraatactieprogramma afdoende zijn om de gestelde doelen voor 2027 te halen. Het voorliggende rapport is een vervolg op de in mei 2015 door het PBL gepubliceerde tussentijdse rapportage (PBL 2015). Nieuw in dit eindrapport zijn onder andere de onderdelen verontreinigende stoffen en rijkswateren, waarvoor destijds nog geen gegevens beschikbaar waren. Ook nieuw zijn de resultaten van een analyse waarin op basis van meetgegevens de toestand en trend in het verleden zijn bepaald.
    Hiep hiep hulpsel!
    Kleis, R. ; Dijksma, R. - \ 2015
    Resource: weekblad voor Wageningen UR 10 (2015)4. - ISSN 1874-3625 - p. 12 - 13.
    hydrologie - waterlopen - achterhoek - studenten - meting - universitair onderzoek - stroomgebieden - hydrology - streams - achterhoek - students - measurement - university research - watersheds
    Diep in de Achterhoek ligt een van de best bemeten en begrepen beken van de wereld. Al vijftig jaar zijn Wageningse wetenschappers en studenten hier kind aan huis.
    Determining the saturated vertical hydraulic conductivity of retention basins in the Oum Zessar watershed, Soutern Tunisia
    Bosch, S. van den; Hessel, R. ; Ouessar, M. ; Zerrim, A. ; Ritsema, C.J. - \ 2014
    Wageningen/Médenine : Alterra, Wageningen/Institut des Régions Arides, Tunisia (Report / WAHARA number 22) - 136
    waterbeheer - stroomgebieden - hydraulisch geleidingsvermogen - tunesië - water management - watersheds - hydraulic conductivity - tunisia
    Metabolite formation in water and in sediment in the TOXSWA model : theory and procedure for the upstream catchment of FOCUS streams
    Adriaanse, P.I. ; Beltman, W.H.J. ; Berg, F. van den - \ 2014
    Wageningen : Alterra, Wageningen-UR (Alterra-rapport 2587) - 49
    waterverontreiniging - waterbodems - pesticiden - stroomgebieden - risicoanalyse - modellen - water pollution - water bottoms - pesticides - watersheds - risk analysis - models
    Het TOXSWA model is uitgebreid met de beschrijving van vorming en omzetting van metabolieten in water en sediment. Op EU niveau wordt TOXSWA gebruikt in de aquatische risico beoordelingsmethodiek van bestrijdingsmiddelen om blootstellingsconcentraties te berekenen in de diverse water typen van de zogenaamde EU-FOCUS oppervlaktewater scenario’s. Voor de scenario’s met FOCUS riviertjes is er een bovenstrooms stroomgebied van 100 ha waarvan 20 ha met bestrijdingsmiddel is behandeld. Bij deze scenario’s willen we rekening houden met metabolieten die in het stroomgebied zijn gevormd. Daarom is een procedure ontwikkeld om de metaboliet concentraties en fluxen te corrigeren voor de FOCUS riviertjes, gevoed door het gedeeltelijk behandelde stroomgebied. De correctiefactoren van de procedure kunnen op twee manieren worden bepaald: (i) een simpele manier, waarbij de correctiefactor een functie is van de omzettingssnelheid van de moederstof en (ii) een meer gedetailleerde manier waarbij de correctiefactor een functie is van de omzettingssnelheid van zowel de moederstof als van de metaboliet, alsmede van de verblijftijd van de moederstof in het bovenstroomse stroomgebied.
    From basalts to badlands : modelling long-term landscape response to lava damming of an upland catchment in western Turkey
    Gorp, W. van - \ 2014
    Wageningen University. Promotor(en): Tom Veldkamp, co-promotor(en): Jeroen Schoorl; Arnaud Temme. - Wageningen : Wageningen University - ISBN 9789462570481 - 182
    landschap - geologie - landinrichting - evolutie - modelleren - stroomgebieden - tektoniek - vulkanische lava - pleistoceen - turkije - landscape - geology - land development - evolution - modeling - watersheds - tectonics - volcanic lava - pleistocene - turkey

    Combining field reconstruction and landscape evolution modelling can be useful to investigate the relative role of different drivers (tectonics, climate, local base level) on long term catchment evolution. In this thesis, field reconstruction and landscape evolution modelling are combined to unravel the long-term (300 ka) response to lava damming events of evolution of the Geren Catchment, a tributary of the upper Gediz river near Kula, Western Turkey. This catchment was considered suitable for such a study because its high preservationof remnant landscape surfaces and fluvial terraces which could be dated, while its base level evolution could be reconstructed by identifying and dating lava flows.

    In Chapter 2, landscape evolution modelling of an idealized catchment revealed long-term (15 ka) catchment response to natural damming. Evolution of a high erodible and low erodible landscape was simulated using landscape evolution model (LEM) LAPSUS (LandscApe procesS modelling at mUlti dimensions and Scales). The natural dam was given four different erodibilities, to mimic both the potentially more erodible landslide dams and resistant lava dams. In a low erodible landscape damming led to persistent preservation of the sediment wedge formed behind the dam, while in a high erodible landscape, damming additionally led to knickpoint persistence, hampered incision of the main river and stream rerouting. The highest erodible dam was almost removed after 15 ka, while its sediment wedge was still partly present. Comparison of results with natural dam events from literature showed that modelled response characteristics are observed in actual situations and that simulations on Quaternary timescales are useful.

    In Chapter 3, field reconstruction resulted in a young lava flow being age constrained to the late Holocene (3.0 – 2.6 ka), by luminescence dating of fluvial sands below and on top of the flow. This lava flow dammed the Gediz river at two locations. the upstream lake was silted, while the downstream lake was not. Dams were breached catastrophically and possibly in a cascading event. The Gediz created an epigenetic gorge and its current river bed is still not at its pre-lava flow level. Results are summarized in a conceptual diagram. Furthermore, field reconstruction and 40Ar/39Ar dating revealed multiple lava dam events which have infrequently raised and lowered the base level of the Geren Catchment in the middle to late Pleistocene (311 – 175 ka). Sediment-capped palaeosurfaces in the Geren suggest change from an active fluvial system to a more lacustrine environment in the middle Pleistocene, followed by fluvial reactivation and stepped incision in the late Pleistocene.

    A second landscape evolution modelling study was conducted in Chapter 4, on a 300 ka timescale, with a larger catchment. Four scenarios have been applied on a reconstructed paleodem of the Geren Catchment. In the first scenario, the palaeodem was given constant rainfall for 300 ka. In the second scenario, three short (1 ka) damming events were added at its catchment outlet. In the third scenario, the palaeodem endured gradual base level lowering at its outlet, based on the known incision rate of its base level, the Gediz river. In the fourth scenario, base level lowering and damming events were combined. Results were interpreted by evaluating 1 ka-averaged net erosion, catchment sediment storage, longitudinal profile development and spatial differences in net erosion and sediment storage. Results showed that the net erosion signal of the catchment is complex in all cases. However, average net erosion and its variability increased due to constant base level lowering. Additionally, alternating phases of high and low variability occurred in net erosion, where high variability coincided with a strong decrease in total catchment sediment storage. Adding damming events to the gradual base level lowering scenario generated similar average net erosion as the base level lowering scenario, however its temporal pattern showed significantly different alternation of high and low variability periods. Furthermore, dampened upstream erosion was observed. Over time, this dampening migrates upstream indicating a long-term legacy of short term dam events.

    Field reconstruction and landscape evolution modelling were combined in Chapter 5, to be able to reconstruct and understand actual Geren catchment response to identified base level evolution over a 300 ka period. In all simulations, rainfall and vegetation are varied over time based on arboral pollen. Because exact significance and duration of dam events were not known, three scenarios of landscape evolution in the Geren Catchment were investigated: i) uplift driven gradual base level lowering, ii) gradual base level lowering and short damming events and iii) gradual base level lowering and long damming events. Output was evaluated for erosion-aggradation evolution in trunk gullies at two different distances from the catchment outlet. Climate influences erosion – aggradation activity in the upstream reach, although internal feedbacks influence timing and magnitude. Scenario i shows the most correlation with the climate signal, although its correlation is weak. Lava damming events leave an aggradation signal in the downstream reach, while complex and lagged response to these dams obscure correlations with climate and leave a legacy of the past in current landscape evolution. Catchment response of the long dam scenario correspond best with field reconstruction and dating. The combination of climate and base level explains a significant part of the landscape evolution history of the Geren Catchment.

    In Chapter 6, a reflection and synthesis of Chapters 2-5 is presented. Indications for response to tectonics, climate and damming events are discussed separately for both field and modelling results. It is concluded that (lava) damming events of Pleistocene age can hamper, but also enhance incision on a 300 ka timescale. Furthermore, they can still have effect on current and future catchment evolution. However, catchment response to this evolution is complex and catchment specific and model results do not exactly reproduce its catchment history. An aggregated landscape evolution model output such as stream bed elevation change can be useful for comparison with fluvial terrace sequences. Combining field reconstruction and modelling suggests that the 300 ka incision history of the Geren is best explained if the catchment endured prolonged dam events. The combination of field reconstruction, dating and landscape evolution modelling therefore can enhance our understanding of long-term evolution of a specific landscape and increases knowledge on long term impact of past events on current catchment complexities and it is suggested to embed this research approach more structurally in long-term landscape reconstructions.

    Assessing and communicating climate change uncertainties : case of the Rhine basin
    Pelt, S.C. van - \ 2014
    Wageningen University. Promotor(en): Pavel Kabat; Bas Arts; B.J.J.M. van den Hurk. - Wageningen : Wageningen University - ISBN 9789461738332 - 200
    waterbeheer - klimaatverandering - onzekerheid - communicatie - risicobeheersing - simulatiemodellen - neerslag - hoogwaterbeheersing - risicoschatting - stroomgebieden - rijn - water management - climatic change - uncertainty - communication - risk management - simulation models - precipitation - flood control - risk assessment - watersheds - river rhine
    The main aim of this thesis is to analyse the climate change uncertainties that are important to take into account for long term water management and to explore the communication of these uncertainties. The study design combines natural and social scientific theories and methods and consists of three different elements: 1) an assessment of the dominant uncertainty for changes in mean and extreme precipitation over the Rhine basin; 2) an assessment of the impact of the main uncertainties on changes in flood risk and associated damage in the Rhine basin and 3) an exploration of the use of simulation gaming to communicate about climate change uncertainties to water managers.
    Overijsselse Vecht : Meer ambitie gevraagd
    Willems, D. ; Corporaal, A. - \ 2013
    Het Waterschap 9 (2013). - ISSN 1380-4251 - p. 29 - 29.
    rivieren - stroomgebieden - gereguleerde rivieren - herstelbeheer - deregulering - opinies - waterschappen - overijssel - rivers - watersheds - regulated rivers - restoration management - deregulation - opinions - polder boards
    De grensoverschrijdende Vecht heeft klasse. In potentie althans. Momenteel ligt ze er geknot bij: gestuwd en rechtgetrokken - een verstoord, kwetsbaar watersysteem. Hulp is onderweg: het breedgedragen programma Ruimte voor de Vecht beoogt meer veiligheid en meer recreatie in een meer natuurlijke (halfnatuurlijke) laaglandrivier. Maar is dit genoeg? De auteurs pleiten voor meer ambitie.
    Watergebruik in de agrarische sector 2001-2011, naar stroomgebied
    Meer, R.W. van der - \ 2013
    Den Haag : LEI, onderdeel van Wageningen UR (Nota / LEI Wageningen UR 13-092) - 41
    watergebruik - stroomgebieden - landbouw - akkerbouw - graslanden - beregening - glastuinbouw - vollegrondsteelt - veehouderij - inventarisaties - water use - watersheds - agriculture - arable farming - grasslands - overhead irrigation - greenhouse horticulture - outdoor cropping - livestock farming - inventories
    Ten behoeve van de jaarlijkse CBS-publicatie Milieurekeningen en het Compendium voor de Leefomgeving levert LEI Wageningen UR cijfers aan het CBS met betrekking tot het watergebruik in de agrarische sector. Gebaseerd op de in EU verband bepaalde stroomgebieden van Nederland (Rijn-Noord; Eems; Rijn-Oost; Rijn-Midden; Rijn-West; Schelde en Maas). Hierbij is het gewenst om rekening te houden met de structuur van de bedrijven in de afzonderlijke stroomgebieden.
    Validatie van PLEASE op regionale schaal : fosfaatbelasting van het oppervlaktewater in de stroomgebieden Quarles van Ufford, Drentse Aa, Krimpenerwaard en Schuitenbeek
    Pleijter, M. ; Salm, C. van der - \ 2013
    Wageningen : Alterra (Alterra-rapport 1968.3) - 90
    fosfaat - fosfor - modellen - oppervlaktewater - waterkwaliteit - oppervlaktewaterkwaliteit - waterbeheer - stroomgebieden - oppervlakkige afvoer - landbouw - krimpenerwaard - zuid-holland - drenthe - phosphate - phosphorus - models - surface water - water quality - surface water quality - water management - watersheds - runoff - agriculture - krimpenerwaard - zuid-holland - drenthe
    Het model PLEASE berekent op basis van eenvoudig te meten perceelskenmerken, zoals grondwaterstand, fosfaattoestand en fosfaatbindend vermogen, de fosfaatbelasting van het oppervlaktewater. Voor het gebruik van PLEASE in de praktijk is het belangrijk om informatie te hebben over de validiteit van de berekende fluxen. In deze studie wordt het model PLEASE toegepast op vier stroomgebieden en zijn de door PLEASE berekende fosfaatverliezen vergeleken met de gemeten P-fluxen op het uitstroompunt van de stroomgebieden. Bij de berekening van de P-flux is gebruik gemaakt van de gemeten fosfaattoestand op puntlocaties en vervolgens zijn deze gegevens opgeschaald naar het hele stroomgebied. De berekende waterfluxen worden door PLEASE, op basis van geïnterpoleerde invoergegevens, in het Schuitenbeek gebied met 12% overschat. In de andere drie stroomgebieden onderschat PLEASE de waterafvoerfluxen enigszins. De berekende P-afvoerfluxen liggen voor drie stroomgebieden hoger dan de gemeten P-afvoer op de uitstroompunten, in Krimpenerwaard is de berekende P-afvoer aanzienlijk lager dan de gemeten P-vracht op het uitstroompunt. Wanneer rekening wordt gehouden met 50% retentie van P in de waterlopen kan gesteld worden dat PLEASE de P-afvoer vanuit de stroomgebieden onderschat. De oorzaak van deze onderschatting is niet precies aan te geven. In de Krimpenerwaard waar eutrofe veenpakketten voorkomen worden waarschijnlijk te lage achtergrondconcentraties gehanteerd. Andere oorzaken voor de onderschatting kunnen zijn: het verwaarlozen van erfafvoeren en locale lozingen, onderschatting van de verliezen door oppervlakkige afspoeling, te hoge sorptieconstanten of een onderschatting van het voorkomen van hot-spots. Daarnaast kan ook de onzekerheid in de gemeten afvoercijfers, de inzichten over retentie in het oppervlaktewater leiden tot een mismatch tussen meting en modelresultaten.
    Participatory integrated watershed management in the north-western highlands of Rwanda
    Kagabo, M.D. - \ 2013
    Wageningen University. Promotor(en): Leo Stroosnijder, co-promotor(en): Saskia Visser. - [S.l.] : s.n. - ISBN 9789461735492 - 104
    integraal waterbeheer - waterbeheer - beheer van waterbekkens - stroomgebieden - hooglanden - duurzaam bodemgebruik - duurzaamheid (sustainability) - rwanda - integrated water management - water management - watershed management - watersheds - highlands - sustainable land use - sustainability - rwanda

    This thesis is the result of assessments on the extent of existing resource use and management practices using a Participatory Integrated Watershed Management (PIWM) as a viable approach to promote best soil water conservation (SWC) measures towards more sustainable land use. The study was conducted in two contrasting agro-ecological zones of the north-western highlands of Rwanda, namely; Gataraga and Rwerere in the framework of “Agasozi ndatwa” referred to as PIWM. "Agasozi ndatwa" program is implemented at watershed scale and involves investments from the government in establishing soil and water conservation structures as well as other development related activities. A stratification sampling approach was used in selecting the study area. The first strata consisted of a watershed and the second-level of strata consisted of villages. Two villages with boundaries that nearly coincided with that of the micro-watershed were selected.The studywas started by assessing the ecological and economic sustainability of smallholder farms using the level of nitrogen recycling between farm activities and farm income as indicators. Soil fertility management components including farm inputs and improved farming systems combined with the knowledge on how to adapt these practices to local conditions at field, farm and watershed levels were evaluated. Following a proper participatory assessment of soil and water conservation, a field experiment was conducted to explore the efficiency of 20+ year old slow forming terraces in farmer’s fields. Finally, the impact of PIWM activities on Natural Resource Management (NRM), crops and livestock productivity on farmers’ livelihoodwas assessed and the integration of several policies that are operating simultaneously in the watershed was evaluated.Nutrient balances and flows differed for the two agro-ecological zones due to differences in crop management and the importance of livestock. Positive nutrient balances were found for relatively fertile volcanic soils, but on steep slopes and acidic soils, N, P and K stocks were declining at rates of 8.6, 1.4 and 17.5 kg ha-1 year-1, respectively. Nitrogen recycling between farm activities was low, varying between 1.8 and 6 %, which may decrease the adaptability and reliability of the current farming systems. Integrated Soil Fertility Management (ISFM) component treatments comprising thecombination of fertilizer, FYM and improved seeds significantly increased yields but resulted (i) in a lower Nitrogen Agronomic Efficiency (N-AE) across sites and on relatively fertile foot slopes and (ii) in a lower marginal rates of return (MRR) due to the high cost of seeds and N fertilizer. Slow forming terraces of 20+ year old showed a marked “within” spatial difference in both soil quality and crop yield. The soil in the lower part of the terraces showed as much as 57% more organic carbon content and 31% more available phosphorous than the soil in the upper part. The marked soil fertility gradients indicate that the sustainability of slow-forming terraces is threatened, unless a site-specific fertilizer strategy is developed. Results suggest that an PIWM approach has the potential of improving farmers’ livelihoods and increasing the resilience of a degraded environment. Furthermore, due to PIWM approach, synergy of policies was effective leading to (i) positive impact on the size and composition of livestock, (2) the availability and use of manure, (3) the increase of production of fodder and (4) the reduction of soil loss.

    Watergebruik in de agrarische sector 2009-2010, naar stroomgebied in Nederland
    Meer, R.W. van der - \ 2013
    Den Haag : LEI, onderdeel van Wageningen UR (Nota / LEI : Onderzoeksveld Sector & ondernemerschap ) - 24
    watervoorziening - watergebruik - landbouwsector - akkerbouw- en tuinbouwbedrijven - beregening - veehouderij - visserij - stroomgebieden - neerslag - statistische gegevens - water supply - water use - agricultural sector - crop enterprises - overhead irrigation - livestock farming - fisheries - watersheds - precipitation - statistical data
    Het CBS heeft aangegeven behoefte te hebben aan cijfers over het watergebruik in de land- en tuinbouwsectoren naar de 7 stroomgebieden in Nederland. Het watergebruik wordt in dit achtergronddocument voor 5 landbouwsectoren (akkerbouw, fruit, tuinbouw, veehouderij, overige landbouw) en de visserijsector bepaald. De 5 sectoren bestaan uit meerdere (27) subsectoren. In de statistieken worden de volgende typen water onderscheiden: leidingwater (drenking en overig), gietwater, grondwater voor irrigatie, oppervlaktewater voor irrigatie, grond-/oppervlaktewater voor irrigatie, en grond-/oppervlaktewater voor drenking. Daarnaast wordt het beregende areaal gerapporteerd.
    On the propagation of drought : how climate and catchment characteristics influence hydrological drought development and recovery
    Loon, A.F. van - \ 2013
    Wageningen University. Promotor(en): Remko Uijlenhoet, co-promotor(en): Henny van Lanen. - [S.l.] : s.n. - ISBN 9789461735010 - 196
    droogte - waterstress - waterbeheer - hydrologie - klimaat - hydrologie van stroomgebieden - stroomgebieden - modellen - drought - water stress - water management - hydrology - climate - catchment hydrology - watersheds - models

    Drought is a severe natural disaster resulting in high economic loss and huge ecological and societal impacts. In this thesis drought is defined as a period of below-normal water availability in precipitation (meteorological drought), soil moisture (soil moisture drought), or groundwater and discharge (hydrological drought), caused by natural variability in climate. Drought propagation is the change of the drought signal as it moves from anomalous meteorological conditions to a hydrological drought through the terrestrial part of the hydrological cycle. The objective of this PhD research is to investigate the processes underlying drought propagation and their relation with climate and catchment characteristics, both on the catchment scale and on the global scale.
    The catchment-scale studies are based on five headwater catchments in Europe with contrasting climate and catchment characteristics. In one of these case study areas, anthropogenic influence on the water system was significant, resulting in severe water scarcity. As I only study natural processes in this thesis, there was a need to separate drought (as defined in this thesis) from human-induced water scarcity in this case study area. I proposed an observation-modelling framework that consists of a hydrological model to simulate the ‘naturalised’ situation and an anomaly analysis method to quantify drought and water scarcity events. Both the time series and the anomaly characteristics of the ‘disturbed’ and ‘naturalised’ situation were compared to quantify human and natural influences on the hydrological system.
    After simulation of hydrometeorological variables of all case study areas with a conceptual hydrological model and drought identification with the variable threshold level method, time series and characteristics of drought events were analysed. I classified the drought events into six hydrological drought types that are the result of the interplay of temperature, precipitation, evapotranspiration and storage in different seasons. The most common hydrological drought type develops as a result of a rainfall deficit. However, in the development of the most severe hydrological drought events temperature and storage-related processes play an important role, for example through a lack of recovery of the drought.
    As I aimed to investigate drought propagation also on larger scales, I tested an ensemble mean of a number of large-scale models (both land-surface models and global hydrological models) on their ability to reproduce the drought propagation processes found in the case study areas. The large-scale models did simulate general aspects of drought propagation (e.g. fewer and longer drought events in discharge than in precipitation), but the above-mentioned effects of temperature and storage-related processes were only partly reproduced. In the large-scale model ensemble, daily runoff reacted almost immediately to changes in precipitation, resulting in important deficiencies in drought simulation in cold and semi-arid climates and regions with large storage. For the time being, this limits the use of large-scale models for the study of processes underlying drought propagation on a global scale.
    Consequently, I used a synthetic conceptual hydrological model to study drought propagation on the global scale. I focused on climate control by isolating forcing effects from effects of catchment properties. The drought characteristics (duration and deficit combined) of both soil moisture and subsurface discharge exhibited strongly non-linear patterns in seasonal climates. The non-linear effects in soil moisture drought were caused by the fact that the development of soil moisture droughts in warm seasonal climates is limited by the wilting point. Hydrological droughts in both warm and cold seasonal climates showed a strong increase of deficit with duration due to a lack of recovery in the dry season or snow season, respectively. This effect was strongest in cold seasonal climates, which indicates that for the development and recovery of within-year hydrological drought temperature is an important factor.
    The overall conclusion of this research is that, although drought is a complex, nonlinear phenomenon with drought characteristics varying with climate type and catchment characteristics, generic patterns can be derived that reflect the different hydrological processes underlying drought propagation. These processes result in different hydrological drought types that are shown to play a role both on the catchment scale and on the global scale. The non-linear effects of snow and storage-related processes on drought are not incorporated sufficiently in the currently-used large-scale models and drought indices. Possible future steps include more focus on catchment control, in particular the representation of storage, and the role of temperature and evapotranspiration. Additionally, the findings of this research can be applied to hydrological drought forecasting, prediction in ungauged basins, and prediction under global change.

    Evaluatie landbouw en KRW : evaluatie meststoffenwet 2012: deelrapport ex post
    Boekel, E.M.P.M. van; Bogaart, P.W. ; Gerven, L.P.A. van; Hattum, T. van; Kselik, R.A.L. ; Massop, H.T.L. ; Mulder, H.M. ; Walsum, P.E.V. van; Bolt, F.J.E. van der - \ 2013
    Wageningen : Alterra (Alterra-report 2326) - 94
    landbouw - stikstof - fosfaat - kaderrichtlijn water - waterverontreiniging - modellen - uitspoelen - oppervlaktewater - stroomgebieden - mestbeleid - agriculture - nitrogen - phosphate - water framework directive - water pollution - models - leaching - surface water - watersheds - manure policy
    In opdracht van het ministerie van Economische zaken, Landbouw en Innovaties (EL&I) is in 2007 een onderzoekstraject ingezet om inzicht te verschaffen in de verwachte realisatie van de KRW-doelen en welke aanvullende maatregelen mogelijk en kosteneffectief zijn. Voor het beantwoorden van de kennisvragen is het modelinstrumentarium ECHO ontwikkeld. De plausibiliteit van de model-resultaten zijn in beeld gebracht door de berekeningen te vergelijken met metingen in het oppervlaktewater. De modelresultaten worden beter door het gebruik van nieuwe uit- en afspoelingsgegevens op basis van STONE 2.4 en retentie in het oppervlaktewater. De toestand en trends in het oppervlaktewater zijn in het kader van de Evaluatie Meststoffenwet 2012 in beeld gebracht op basis van metingen in het oppervlaktewater. Hieruit blijkt dat 30% van de meetpunten in het zoete oppervlaktewater voldoet aan zowel de stikstof- en fosfordoelstellingen van de KRW. De diffuse belasting van het oppervlaktewater is voor een substantieel deel afkomstig uit de landbouw. Uit de studie blijkt verder dat aanvullende maatregelen kosteneffectief kunnen worden ingezet om de nutriëntenbelasting te verlagen als rekening wordt gehouden met de kosteneffectiviteit van de maatregelen, de gewenste nutriëntenconcentraties in het oppervlaktewater en afwenteling vanuit bovenstroomse gebieden.
    Attention to safety 2
    Ward, P.J. ; Aerts, J.C.J.H. ; Pelt, S.C. van; Keizer, O. de; Hurk, B.J.J.M. van den; Beersma, J.J. ; Buishand, T.A. - \ 2012
    Nieuwegein : Programme Office Climate changes Spatial Planning (KvR 051/12) - ISBN 9789088150449 - 44
    klimaatverandering - risicoschatting - overstromingen - modellen - rijn - stroomgebieden - climatic change - risk assessment - floods - models - river rhine - watersheds
    Tot op heden heeft onderzoek naar toekomstig overstromingsrisico vooral gebruik gemaakt van de scenarioaanpak. Het belangrijkste doel van deze studie is om een demonstratie te geven van een methode voor het produceren van probabilistische schattingen van overstromingsrisico’s als gevolg van klimaatverandering. Het onderzoek richt zich op twee casestudy trajecten langs de Rijn: Bonn-Duisburg en Mainz-Koblenz.
    Dynamic modelling of phosphorus export at river basin scale based on Global NEWS
    Strokal, M. ; Vries, W. de - \ 2012
    Wageningen : Alterra, Wageningen-UR (Alterra-report 2321) - 100
    fosfor - rivieren - stroomgebieden - transport - dynamisch modelleren - phosphorus - rivers - watersheds - transport - dynamic modeling
    Fysieke onderlegger voor het deltaprogramma : kansen voor waterconservering on regionale stroomgebieden
    Massop, H.T.L. ; Kwakernaak, C. ; Bakel, P.J.T. van - \ 2012
    Wageningen : Alterra (Alterra-rapport 2287) - 34
    wateraanvoer - wateropslag - ondergrond - watertekort - zoet water - klimaatverandering - stroomgebieden - water advance - water storage - subsoil - water deficit - fresh water - climatic change - watersheds
    Door klimaatverandering zal de beschikbaarheid van voldoende zoet water verminderen. Dit rapport gaat in op de vraag welke kansen er in verschillende regio’s zijn om overschot aan regenwater tijdelijk te conserveren in de bodem en in het regionaal oppervlaktewatersysteem om deze voorraad te kunnen benutten in tijden van watertekort. In kaartbeelden wordt weergegeven waar waterconservering in regionale stroomgebieden kansrijk is. Daarmee ontstaat inzicht in de mate waarin en de wijze waarop regionale stroomgebieden zelfvoorzienend kunnen worden, dus onafhankelijk van de aanvoer van gebiedsvreemd water. Ook geeft het rapport een overzicht van mogelijke maatregelen voor waterconservering.
    Driver-pressure-impact and response-recovery chains in European rivers: observed and predicted effects on BQEs
    Feld, C.K. ; Dahm, V. ; Lorenz, A. ; Logez, M. ; Marzin, A. ; Verdonschot, P.F.M. ; Michels, H.C.U. ; Keizer-Vlek, H.E. - \ 2011
    Brussel : European Commission - 227
    stroomgebieden - aquatische ecologie - ecologisch herstel - rivieren - biota - databanken - europa - watersheds - aquatic ecology - ecological restoration - rivers - biota - databases - europe
    The report presented in the following is part of the outcome of WISER’s river Workpackage WP5.1 and as such part of the module on aquatic ecosystem management and restoration. The ultimate goal of WP5.1 is to provide guidance on best practice restoration and management to the practitioners in River Basin Management. Therefore, a series of analyses was undertaken, each of which used a part of the WP5.1 database in order to track two major pathways of biological response: 1) the response of riverine biota to environmental pressures (degradation) and 2) the response of biota to the reduction of these impacts (restoration). This report attempts to provide empirical evidence on the environment-biota relationships for both pathways.
    Eindrapportage Hotspot Oude Vaart - Reest
    Schaap, B.F. ; Geertsema, W. ; Schotman, H. ; Visser, J.C. ; Vree, L.G. de - \ 2011
    Den Haag : Nationaal Onderzoeksprogramma Klimaat voor Ruimte (KvR) - ISBN 9789088150418 - 73
    stroomgebieden - beekdalen - watersystemen - scenario-analyse - klimaatfactoren - klimaat - overijssel - drenthe - watersheds - brook valleys - water systems - scenario analysis - climatic factors - climate - overijssel - drenthe
    De beekdalen in Drenthe zijn bij uitstek gebieden waar de effecten van de klimaatverandering merkbaar zullen zijn. Dat wordt veroorzaakt doordat beeksystemen kwetsbaar zijn voor klimatologische veranderingen. Daarnaast worden de in het gebied aanwezige functies landbouw en natuur in sterke mate beïnvloed door klimaatverandering. Hierbij spelen veranderingen in de waterhuishouding een belangrijke rol.
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