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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    Multi-scale tectonic controls on fluvial terrace formation in a glacioeustatically-dominated river system: inference from the lower Min¿o terrace record
    Viveen, W. - \ 2013
    Wageningen University. Promotor(en): Tom Veldkamp, co-promotor(en): R.T. van Balen; J.R. Vidal Romani; Jeroen Schoorl. - S.l. : s.n. - ISBN 9789461737281 - 222
    fluvial soils - terrassen - rivierterrasgronden - tektoniek - klimaatverandering - zeespiegelschommelingen - rivieren - rivierdalen - spanje - portugal - fluvial soils - terraces - river terrace soils - tectonics - climatic change - sea level fluctuations - rivers - river valleys - spain - portugal

    The general aim of this thesis is to untangle the interacting effects of climate, glacioeustacy, and regional, and local tectonics on fluvial terrace formation. The NW Iberian lower Miño River valley was chosen as a study site, because for this region, a very detailed, long-term, climate record is available. The lower Miño is situated near the Atlantic Ocean, which ensures that the influence of changing past sea levels was registered in the terrace record. Then, there is controversy about the presence or absence of tectonic activity, although a well-developed network of pre-existing faults and seismic activity in the region suggest that tectonic activity is present. Lastly, a completely preserved terrace sequence makes it possible to study the evolution of the area in detail. These, and more details, are found in Chapter 1.

    In Chapter 2, a regional assessment of recent tectonic activity is made. Studies on faulted terrace deposits and the recognition of small, fault-bounded tectonic basins indicate the presence of neo-tectonic activity. Further evidence is gathered from a tectono-geomorphic analysis, whereby deeply incised valleys, as well as asymmetrically-developed tributary catchments, and the presence of knick points in river profiles that coincide with the presence of structural lineaments, show that the eastern part of the study area experiences tectonic deformation. It is proposed that due to the non-optimal angle between the orientation of the pre-existing faults, and the current horizontal stress orientation, these older faults are re-activated, resulting in strain transfer from one fault segment to another. This results in differential block movements leading to local extension and basin subsidence. Alternatively, strike-slip activity may have caused the tectonic basins, but for this mechanism no evidence was found.

    The focus of Chapter 3 is on a local terrace staircase near the village of Vila Meã. First, the terrace staircase and associated fluvial deposits are described in detail. Then, an age model for the Vila Meã terraces is presented on basis of thermoluminescence and Cosmogenic Ray Exposure (CRE) dating. Minimum ages of up to 650 ka are calculated. On basis of these ages, and terrace surface altitudes, maximum incision rates of 0.07 to 0.09 m ka-1 are reconstructed. It is then discussed that these rates can be used as proxies for regional, vertical tectonic uplift. In the final part of the Chapter, new ideas are presented on the evolution of the lower Miño fluvial terraces. Based on observations made from the terrace deposits, and the proximity of a narrow, steep continental shelf, it is suggested that the fluvial terraces were formed during the initial period of sea level fall, and subsequently incised. Vertical uplift would then have occurred to preserve the terraces above the current river bed.

    In Chapter 4, the focus shifts from a local terrace staircase to the regional terrace record. The entire 55-km long terrace section of the lower Miño is investigated, and 4 selected terrace transects are discussed in terms of number of terraces and sedimentology. Because there is disagreement on the exact number of terraces and their correlations, a new long-distance terrace correlation scheme is presented. The new scheme is based on studies of weathered quartzite gravels in the 4 selected transects. Observed similarities in weathering rate between the transects leads to a proposed terrace correlation gradient of 1 m km-1. The often used correlation model that the terraces tread parallel to the current river bed (gradient 0 m km-1) is then rejected. The second half of the Chapter focuses on a longitudinal profile modelling experiment with the FLUVER 2 model. The evolution of the entire Miño-Sil system is modelled over a time period of 450 ka. The outcomes show that a regional uplift rate of 0.08 m ka-1 in combination with glacioeustatic movements seem to be responsible for terrace formation in the lower Miño valley, and thus confirm the earlier hypotheses in Chapter 3. Climate-induces variations in discharge intensity or timing do not have a dominant effect on terrace formation. The outcomes furthermore indicate that the CRE ages presented in Chapter 3, appear to be very close to exact timing of terrace abandonment.

    The results of the foregoing Chapters are integrated and implemented in Chapter 5, resulting in a new, detailed, fluvial terrace map of the entire 67-km reach of the lower Miño River. Both the Spanish and Portuguese part is incorporated. The map is derived from detailed mapping from a 5-m Digital Elevation Model (DEM) and over 1500 hours of fieldwork. The map shows the regional distribution of 10 terrace levels and one floodplain level, as well as 9 tectonic basins. A layer with fault elements gives a structural tectonic context to the map. Additional layers give information about more than 400 sites with mapped terrace sediment thicknesses and palaeoflow directions. Results from this mapping exercise show the highly fragmented nature of terrace and basin distribution, which is controlled by N-S, E-W and NW-SE trending faults. The map also suggests the presence of unpaired terraces along the river, which may be caused by localised differential movements of tectonic blocks.

    These localised movements are the topic of Chapter 6. Here, the interactions between regional vertical uplift, local basin subsidence, and unequal uplift on both sides of the Miño River on terrace formation are investigated by means of a forward modelling exercise with the TERRACE model. The model simulations that match best with mapped terraces and fluvial sediment thicknesses are the ones that incorporate all three effects of vertical uplift, basin subsidence, and unequal uplift. This shows that terrace preservation is the complex end result of three, interacting, tectonic processes. A regional uplift rate of 0.10 m ka-1 gave the best results, which is slightly higher than the rate of 0.08 m ka-1 presented in Chapter 3. This confirms that regional uplift increases from the coast towards the east, which is in agreement with the findings of Chapter 2. Another important result is that the interacting effect of the three aforementioned tectonic processes can lead to fill terraces one valley side, and strath terraces at the other.

    In Chapter 7, all findings of the previous Chapters are combined. The separate effects of climate change, glacioeustacy, and regional and local tectonic movements on fluvial terrace formation are discussed. This shows that in many published terrace correlation schemes for tectonically active regions, the effects of multi-scale tectonics are insufficiently incorporated or considered. The same applies for the possible effects of variable uplift pulses over middle to late Quaternary timescales. This leads for instance to the separation of fill and strath terraces in a chronological context, because they are still thought to be the resultant of climate-triggered changes in discharge and sediment load of the river. But this thesis shows that they can form at the same time due to localised tectonic movements. The Chapter concludes with a number of recommendations on how to incorporate tectono-geomorphic analysis in fluvial terrace research, which will lead to a better understanding of tectonic control on fluvial terrace formation world-wide.

    Farmers, institutions and land conservation : institutional economic analysis of bench terraces in the highlands of Rwanda
    Bizoza Runezerwa, A. - \ 2011
    Wageningen University. Promotor(en): Erwin Bulte, co-promotor(en): Paul Hebinck. - S.l. : s.n. - ISBN 9789085859307 - 123
    ontwikkelingseconomie - boeren - institutionele economie - instellingen - landbouwgrond - bodembescherming - waterbescherming - erosie - terrassen - rwanda - oost-afrika - minst ontwikkelde landen - development economics - farmers - institutional economics - institutions - agricultural land - soil conservation - water conservation - erosion - terraces - rwanda - east africa - least developed countries
    Adoption of terraces in the Peruvian Andes
    Posthumus, H. - \ 2005
    Wageningen : Wageningen University (Tropical resource management papers no. 72) - ISBN 9789067549578 - 202
    erosie - erosiebestrijding - erosiegevoeligheid - terrassen - terrassering - adaptatie - peru - economie - andes - erosion - erosion control - erodibility - terraces - terracing - adaptation - peru - economics - andes
    Soil erosion is a serious constraint for agriculture and rural development in developing countries. Many efforts are made to promote soil and water conservation (SWC) among farm households. However, adoption of SWC practices is often disappointing. This thesis analyses the benefits of terraces and the adoption behaviour of farm households in the Peruvian Andes. The main beneficial effect of terraces is the increased water availability in the soils. However, terraces will only result in increased production if it is combined with intensified crop management or with crops of high market value. Whether terraces are financially attractive for farmers depends mainly on their personal opportunity cost of labour. Incentives though only slightly increase the profitability of terraces. The decision to participate in a SWC-oriented programme plays a key role in the adoption process. Programmes with a top-down approach have a strong influence on the adoption decision. Participants of these programmes installed SWC practices on the rainfed and degraded fields with steep slopes that are used for extensive agriculture or pasture. Participants of a participatory programme have more individual control on the adoption decision, and they installed terraces on the less degraded fields in order to intensify agricultural production. Production functions revealed that terraces do not result in a significant increase of agricultural output at household level, but labour productivity did increase. Terraces have the potential to increase agricultural production and factor productivity, but whether this is of interest of a farm household, depends on the existing markets. Therefore, programmes have to take into account the scarcity of production factors and the opportunities at local markets. As conditions differ per region, SWC interventions should be decentralised.
    Adoption of terraces in the Peruvian Andes
    Posthumus, H. - \ 2005
    Wageningen University. Promotor(en): Leo Stroosnijder; Arie Kuyvenhoven, co-promotor(en): Jan de Graaff; Ruerd Ruben. - [S.l.] : S.n. - ISBN 9789085042495 - 203
    bodembescherming - peru - terrassen - waterbescherming - economische analyse - innovatie adoptie - soil conservation - peru - terraces - water conservation - economic analysis - innovation adoption
    Soil erosion is a serious constraint for agriculture and rural development in developing countries. Many efforts are made to promote soil and water conservation (SWC) among farm households. However, adoption of SWC practices is often disappointing. This thesis analyses the benefits of terraces and the adoption behaviour of farm households in the Peruvian Andes. The main beneficial effect of terraces is the increased water availability in the soils. However, terraces will only result in increased production if it is combined with intensified crop management or with crops of high market value. Whether terraces are financially attractive for farmers depends mainly on their personal opportunity cost of labour. Incentives though only slightly increase the profitability of terraces. The decision to participate in a SWC-oriented programme plays a key role in the adoption process. Programmes with a top-down approach have a strong influence on the adoption decision. Participants of these programmes installed SWC practices on the rainfed and degraded fields with steep slopes that are used for extensive agriculture or pasture. Participants of a participatory programme have more individual control on the adoption decision, and they installed terraces on the less degraded fields in order to intensify agricultural production. Production functions revealed that terraces do not result in a significant increase of agricultural output at household level, but labour productivity did increase. Terraces have the potential to increase agricultural production and factor productivity, but whether this is of interest of a farm household, depends on the existing markets. Therefore, programmes have to take into account the scarcity of production factors and the opportunities at local markets. As conditions differ per region, SWC interventions should be decentralised
    Participatory appraisal for farm-level soil and water conservation planning in West Usambara highlands, Tanzania
    Tenge, A.J.M. - \ 2005
    Wageningen University. Promotor(en): Leo Stroosnijder. - [S.l.] : S.n. - ISBN 9789085041658 - 163
    bodembescherming - waterbescherming - planning - houding van boeren - economische sociologie - terrassen - grasbanen - tanzania - maatregelen - soil conservation - water conservation - planning - farmers' attitudes - economic sociology - terraces - grass strips - tanzania - measures
    Soil and water conservation (SWC) measures are needed to control soil erosion and sustain agricultural production on the steep slopes of Usambara Mountains. The need for SWC has resulted in the development and promotion of several SWC measures by both governmental and non-governmental programmes. However, there is limited information on their physical effectiveness and financial efficiency to convince farmers to invest in SWC. Furthermore, farmers¿ preferences and the socio-economic factors that influence the adoption of SWC measures have not been adequately considered. As a result, the adoption of many recommended SWC measures is minimal and soil erosion continues to be a problem. This research explored the socio-economic reasons for low adoption of SWC measures in the West Usambara highlands in Tanzania. The research generated both biophysical and socio-economic information that was used to improve the current SWC planning approach. Major SWC measures used in the West Usambara highlands were then appraised using the improved participatory approaches that integrated the physical effectiveness and financial efficiency of the SWC measures and other socio-economic factors of the land users.
    Participatory appraisal for farm-level soil and water conservation planning in West Usambara highlands, Tanzania
    Tenge, A.J.M. - \ 2005
    Wageningen : Wageningen University and Research Centre (Tropical resource management papers no. 63) - ISBN 9789067549042 - 163
    bodembescherming - waterbescherming - planning - houding van boeren - economische sociologie - grasbanen - tanzania - terrassen - maatregelen - soil conservation - water conservation - planning - farmers' attitudes - economic sociology - grass strips - tanzania - terraces - measures
    Soil and water conservation (SWC) measures are needed to control soil erosion and sustain agricultural production on the steep slopes of Usambara Mountains. The need for SWC has resulted in the development and promotion of several SWC measures by both governmental and non-governmental programmes. However, there is limited information on their physical effectiveness and financial efficiency to convince farmers to invest in SWC. Furthermore, farmers¿ preferences and the socio-economic factors that influence the adoption of SWC measures have not been adequately considered. As a result, the adoption of many recommended SWC measures is minimal and soil erosion continues to be a problem. This research explored the socio-economic reasons for low adoption of SWC measures in the West Usambara highlands in Tanzania. The research generated both biophysical and socio-economic information that was used to improve the current SWC planning approach. Major SWC measures used in the West Usambara highlands were then appraised using the improved participatory approaches that integrated the physical effectiveness and financial efficiency of the SWC measures and other socio-economic factors of the land users. http://library.wur.nl/wda/abstracts/ab3733.html
    Reconstructing late quaternary fluvial process controls in the upper aller valley (north Germany) by means of numerical modeling
    Veldkamp, A. ; Berg, M. van den; Dijke, J.J. van; Berg van Saparoea, R.M. van den - \ 2002
    Netherlands journal of geosciences 81 (2002)3-4. - ISSN 0016-7746 - p. 375 - 388.
    geomorfologie - kwartaire afzettingen - tektoniek - terrassen - dalen - simulatiemodellen - geologische sedimentatie - duitsland - rivieren - geomorphology - rivers - geological sedimentation - quaternary deposits - tectonics - terraces - valleys - simulation models - germany - terrace stratigraphy - maas record - europe - uplift - system
    The morpho-genetic evolution of the upper Aller valley (Weser basin, North Germany) was reconstructed using geological and geomorphologic data integrated within a numerical process model framework (FLUVER-2). The current relief was shaped by Pre-Elsterian fluvial processes, Elsterian and Saalian ice sheets, followed by Weichselian fluvial processes. Structural analysis based on subsurface data and morphological interpretations were used to reconstruct uplift/subsidence rates. A detailed analysis led to the hypothesis that we are dealing with either a NNW-SSE or a WSW-ENE oriented compression leading to uplift in the upper Aller valley. It is also hypothesised that the NNW-SSE compression might have caused strike-slip deformation leading to differential block movement and tilt.Two different uplift rate scenarios were reconstructed and used as a variable parameter in numerical modelling scenarios simulating the Late Quaternary longitudinal dynamics of the Aller. Each different scenario was run for 150.000 years and calibrated to the actual setting. The resulting model settings were consequently evaluated for their plausibility and validity. Subsequently, regional semi-3D simulations of valley development were made to test the two tectonic stress hypotheses. Differential tectonic uplift and regional tilt seems to have played an important role in shaping the current valley morphology in the upper Aller. Unfortunately, due to the uncertainties involved, we were unable to discriminate between the two postulated tectonic stress scenarios.
    Platforms and terraces : bridging participation and GIS in joint-learning for watershed management with the Ifugaos of the Philippines
    Gonzalez, R.M. - \ 2000
    Agricultural University. Promotor(en): N.G. Röling; K.J. Beek; M.K. MacCall. - Enschede : ITC - ISBN 9789058082466 - 186
    geografische informatiesystemen - beheer van waterbekkens - natuurlijke hulpbronnen - bedrijfsvoering - terrassering - inheemse kennis - landbouw - terrassen - filippijnen - geographical information systems - watershed management - natural resources - management - terracing - indigenous knowledge - agriculture - terraces - philippines

    Complex multi-actor problem situations in natural resource management (NRM) need the convergence of different knowledge processes, first of all, in understanding and agreeing what the problem is before aspiring for joint-action. This is a joint-learning approach in NRM. Geographic information systems (GIS), with their integrative, analytic, and visualization capabilities, offer promising means to facilitate this approach. However, using GIS relies heavily on specialists that develop and interact with the system, and thus, precludes participation of others NRM actors having no computer skills. Such a limitation can promote dependence on externally-planned intervention and is not desirable. In this research, I explored the use of participatory methods in designing a GIS for facilitating multi-actor learning about their problematic situation in NRM at the local level and communicating the same at the provincial level. This is to reinforce collective effort in understanding, negotiating, and active social construction of natural resources to be jointly managed.

    Joint-learning started when Ifugao farmers and I engaged in tracing back NRM history of the study area which is located in the Northern Philippine uplands of Ifugao. This was done in order to learn about the traditional spatial information system that was used to successfully manage their terraced ecosystem that dates back to more than 2,000 years. By reading historical documentation, interviewing the elderly, and visualizing their NRM territories from their oral descriptions, I was able to establish the old Ifugao society's divisions of spatial responsibility that were parts of independent "water districts." Through spatial dialogue, local farmers participated in interpreting aerial photographs and satellite images, and in designing a prototype GIS which is patterned after their successful baddang (workgroup) in these water districts. By joining local NRM planning activities, I was able to identify potential NRM processes that can be reinforced by GIS, such as monitoring the status of their forests and terraces, and systematizing their trial-and-error reforestation efforts. By demonstrating GIS capabilities in supporting these activities ( e.g., site selection, data aggregation, map generation), and the roles that local and provincial level NRM actors can play in each ( e.g., jointly monitoring conditions, analyzing mapped data, formulating plans and policies), we developed a scheme for inter-actor communication process that can help gather support, identify possibilities and define responsibilities in co-managing their delicate landscape.

    This research was able to identify a room for local participation in such an expert-dependent tool as GIS. It also demonstrated the inter-dependence of different expertise from different disciplines to come together in developing a GIS that can be effective in promoting a multi-actor NRM. Moreover, it showed a different side of GIS from mapping and data management to joint construction of the 'world' to be managed. This is important to extend our understanding of the complex world through exchange of alternative perspectives for common knowledge and wisdom to evolve and hopefully, promote concerted action for a more sustainable NRM. Interesting topics for future research also emerged from this study. The foremost of which is whether expertise and secondary information is enough to design effective practice; or whether interactive technology design promotes better practice.

    International Geographical Union : working group on the geomorphology of river and coastal plains
    Stichting voor Bodemkartering, - \ 1982
    Wageningen : Soil Survey Institute
    geomorphology - valleys - terraces - relief - water erosion - world - geomorfologie - dalen - terrassen - reliëf - watererosie - wereld
    Congres Stiboka
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