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
forests - resilience of nature - fire - flooding - floods - climate - floodplains - vegetation - amazonia - bossen - veerkracht van de natuur - brand - inundatie - overstromingen - klimaat - stroomvlakten - vegetatie - amazonia
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.
Community based fish culture in the public and private floodplains of Bangladesh
Mahfuzul Haque, A.B. - \ 2015
Wageningen University. Promotor(en): Leontine Visser, co-promotor(en): M.M. Dey. - Wageningen : Wageningen University - ISBN 9789462574533 - 166
stroomvlakten - visteelt - ontwikkelingsstudies - ontwikkelingseconomie - samenleving - huishoudens - bangladesh - zuid-azië - floodplains - fish culture - development studies - development economics - society - households - bangladesh - south asia
Seasonal floodplains are water bodies that retain water for 5-6 months during which they are suitable to grow fish and other aquatic animals. Out of 2.8 million ha of medium and deep-flooded areas, about 1.5 million ha are estimated to be suitable for Community-Based Fish Culture (CBFC). WorldFish had undertaken a five-year interdisciplinary action research project from 2005-2010 with the overall aim of enhancing the productivity of seasonally occurring floodwaters for the improved and sustained benefit of the livelihoods of the poor. My involvement in this project was as PhD Scholar from 2007-2009 for understanding the different and complex institutional arrangements and its overall impact of governing Community-Based Fish Culture in seasonal floodplains for the sustainable use and maximization of benefits to the targeted people of Bangladesh.
Six seasonal floodplains in different areas of Bangladesh were selected under the action research project implemented by the Department of Fisheries in collaboration with the Bangladesh Agricultural Research Council and the Bangladesh Fisheries Research Institute. For the action research which is the subject of this thesis, three seasonal floodplains were selected in the Brahamaputra, the Padma and the Teesta River Basins located at Mymensingh, Rajshahi and Rangpur districts, respectively. Another three floodplains were selected as control sites in the same river basins located near to the projects sites. The control sites were included in the economic study (Chapters 4 and 5) only. All the six floodplains belong to two types of ownership categories: public floodplains surrounded by private lands.
My thesis is broadly divided into a sociological and an economic part, mainly because of methodological differences. Chapter 2 and Chapter 3 discuss the institutional arrangements and the power and decision-making process of Community-Based Fish Culture management. Chapter 4 addresses the overall economic impact of technical and institutional arrangements of fish culture at both floodplain and household levels. We here employed a random effects model to estimate the impact of participation on fish income. Finally, in Chapter 5 the economic impact of community-based fish culture on expenditure inequality was measured at household level.
In the sociological part, three project floodplains covered the different institutional arrangements for managing the floodplains and maximizing their benefits to different classes of beneficiaries. Power relations between the various key actors or stakeholders were assessed who were directly or indirectly involved in the floodplain, and decision making processes in co-management practices were also studied at different institutional levels. Sociological research methods and techniques including semi-structured interviews, Focus Group Discussions, informal discussions with key informants, and
For the economic analysis of Chapter 4 and Chapter 5, three project floodplains and three control floodplains were selected for comparing the impact of the intervention at beneficiary level and also community level. Household survey data includes a baseline survey on socioeconomic information, three months monitoring on seasonal and monthly basis at community and household levels, as well as an assessment of the floodplains’ natural resource systems. The seasonal survey covered the changes in input use for crop production, changes in quality of output from the agricultural land and the effects of the intervention on crop production. A monthly survey on the 1st and 15th day of the month was conducted to capture the household consumption pattern, especially the frequency and quantity of fish and meat consumption.
Chapter 2 improves our understanding of the complex institutional relationships governing Community-Based Fish Culture in seasonal floodplains in Bangladesh. Formal institutional linkages between DoF, WorldFish Center and the Bangladesh Agricultural Research Council (BARC) played a key role in ensuring success. DoF is a government institution with establishments at different administrative levels. Institutional embedding of DoF through the Fishers Cooperatives (FMC) as implementing institutions appeared highly instrumental. Large numbers of people, including landless poor seasonal fishers, professional landowning fishers, and non-fishing landowners benefited from the successful implementation of the CBFC activities in the floodplains. The outcomes demonstrate a significant increase in income to all classes of beneficiaries through income sharing derived from their involvement in the fisheries cooperatives and fish culture.
In case 2 and case 3 the floodplains under private ownership privately owned land is inundated during the monsoon season; these floodplains are similar in size, with comparable percentages of beneficiaries and similar numbers of communities surrounding the floodplains. However, the distribution of beneficiaries among the classes differs with more landowners than landless seasonal fishers benefitting. FMCs normally allow these non-members to access the floodplains, but only to harvest un-stocked fish using local gears, considering the importance of fishing to their livelihood. This means that the CPR character of the management by the FMCs shows a certain permissiveness or permeable boundary regarding landless non-members under strict spatial and temporal conditions. Regulation and conservation thus guarantee the availability of un-stocked small fish in the floodplains with a high catch by artisanal gears which results in higher incomes and related benefits to the poorer households. Households who own land or ditches in the floodplains do not depend on un-stocked fish as they can have ponds to trap and harvest fish obtained in the wild. Additionally, during the dry season, they may use land in lowland areas for crop production.
Case 1 of the public floodplain surrounded by private lands differs most from the private floodplain cases. Here, the public area is leased out to fishers during the monsoon, including the private land owned by the affluent and politically influential stakeholders. The floodplain is larger than in the other two cases, but both the percentages of landless fishers and of landowners are lower, making the class of the landowning professional fishers the majority among the beneficiaries.
Generally, the rules and regulations that apply to public and privately owned floodplains are written down in a Memorandum of Understanding between DoF and the individual FMC’s in a non-judicial construction. In their regular meetings the FMCs also document the everyday practices of the rules related to fish culture and management in the minutes that are distributed among its members. It appears that in the three cases, comparable rules and regulations for fish culture are applied to the public and to the private floodplains in operational rules, collective choice rule and constitutional rule.
Benefit sharing of the fish production from the floodplains was agreed at the start of project activities by all stakeholders, but their commitment varied between the classes of beneficiaries and across the cases. A significant increase of income for different stakeholders was derived from their involvement in fish culture. In the public floodplain fishers received around 40% of net income increase and the landowners received almost 38% of net income increase, as they had to pay the lease money for the floodplain. But in private floodplain all classes of stakeholders deposited around 25% of their net income in a revolving fund. The fishers group got their income from the final harvesting of fish as they received 50% of the price of the harvest of un-stocked fish and 10-15% of the stocked fish. The landowners received 45-50% of income according to their land. The landless seasonal fishers had open access to the non-stocked fish during the monsoon. Finally, the users of the public as well as the private floodplains contributed a small portion of their income to social work, like the building of a mosque or a Hindu temple.
Chapter 3 firstly assessed the power relations between the various key actors or stakeholders who were directly or indirectly involved in floodplain fisheries in the three sites. Secondly, their shifting power relations and decision making process in co-management practices were studied in the different institutional contexts of the three research sites during WorldFish project intervention. Instead of merely listing the institutions involved, we studied the actual power practices and decisions making processes between the stakeholders in the three cases to gain insight in the different governance models used in CBFC in Bangladesh. Existing co-management arrangements are characterized by unequal power distribution among the different actors, often resulting in the marginalization of the professional fishers and the landless poor fishers. I differentiated between two types of power in the management of floodplain aquaculture and stakeholder involvement, namely a) the power to create rules and decision making procedures, and b) the power to resolve disputes and ensure compliance. The Floodplain Management Committee (FMC) reviews the rules and regulations formulated by the government to complement the vision and roles of the institution, and if there is a need, modify them. Rules and regulations governing access to the public and privately owned floodplains were developed by the Department of Fisheries (DoF) and the FMC. A similar set of rules and regulations was applied to the public and the privately owned floodplains for fish culture. Most of the rules were derived from the national fisheries law. The rules and regulations that were applied to the floodplain were written down in a Memorandum of Understanding between DoF and FMC. Examples are rules and regulations about membership, leadership, boundary and access, allocation, penalties, input, and conflict resolution that were enforced for the management of community based-fish culture.
Magistrate courts at local level in Bangladesh have the power to decide on penalties for offenders in case of violation of the Government Fisheries Act of 2010 (DoF 2013) in the management of fisheries and aquaculture including the floodplain; a range of penalties is stipulated in the Offences and Penalties paragraph of the Act. In addition, in the case of both public and private floodplains, leaders of customary organizations have the authority and power to confiscate illegal nets and penalize offenders by charging monetary fines.
Governance in the context of Community-Based Fish Culture (CBFC) management addresses the dominancy of the land-owning group, informal sets of norms and traditions, and the social network and power relationships between stakeholders. In the public floodplain governance processes resulting in the formation of a responsive, accountable leadership and representative membership appeared vital for the success of CBFC. But, the establishment of successful CBFCs in public floodplains demands continuous institutional support from agencies such as the Department of Fisheries, because an increase in production and income also increases the risk of elite capture, and the possibility of an exploitative. In the private floodplain, there was no specific governance system in place to manage access and use of the floodplains during the wet season, as opposed to the dry months when the lands of the floodplain could be used by individual households for crop production. Thanks to greater accountability of the leaders, and more equal representation of the different stakeholders including active leadership and a supporting role of DOF, leadership problems were few and easily solved. Downward accountability was well established in addition to many efforts by the project.
Chapter 4 examined the overall impact on households involved through the WorldFish project in community-based fish culture in seasonal floodplains, particularly with respect to fish production, consumption, and income generation. Qualitative as well as quantitative methods were deployed to examine the impact of Community-Based Fish Culture starting with a conceptual framework as to how positive impacts take effect. The overall fish production in the floodplains of the project appeared to have increased 274%. Due to project intervention introducing fish culture, 43% of the farmers used floodplain water to meet up irrigation needs instead of ground water and rice production increased by 18.9% for dry-season (Boro) rice and 28.9% for wet-season (Aman) rice in the project floodplain areas.
Increased income is an important economic incentive for the expansion of community-based fish culture in Bangladesh. Over that period, average income from fish production increased to USD 240 for all beneficiaries involved in the project, which is 237% higher than the income of beneficiaries in the control group. Results of the random effects model show that project-involved households significantly increased their fish income compared to the households of the control sites. Furthermore, total household income increased to about USD 175 per household for those who participated in the WorldFish project.
Fish availability increased in the project area from July to December. During these months approximately 68%-75% of the total fish consumption needs of the project beneficiaries could be fulfilled by the newly introduced fish culture in the floodplains. The consumption of nutritional food shows that per capita fish consumption of households in the project sites increased from 1.26 kg per capita per month in the baseline year to 2.31 kg per capita per month in 2009.
Apart from the direct effect on household income and food consumption, CBFC intervention also created the opportunity for employment, backward linkage, and access to market to sell harvested fish. Indirect benefits of the community based fish culture include reduced conflict; improved social capital and greater cooperation in the community.
Expenditure is a better measurement of welfare than income where most of the people are poor and struggle for food. In this study I therefore used data on expenditure instead of income. The results in Chapter 5 show that the CBFC project had a positive and significant impact on food expenditure, as well as on non-food (other basic needs) and overall total expenditure. The impact of CBFC on household expenditure and expenditure inequality was measured by using Propensity Score Matching (PSM) method and Gini decomposition. Results revealed that the overall average food expenditure per year per household (for panel estimation) increased due to participation in the CBFC project from USD 93 to USD 141. Project participants were able to spend significantly more on food compared to non-participants. In addition, expenditure on food was increasing year by year. Moreover, participant households were capable to spend more compared to non-participants on non-food items like cloth, health, education, housing, transport etc. (from USD 45 to USD 74 per year). This non-food expenditure also gradually increased per year. Finally, total household expenditure of CBFC project participants was between USD 134 and USD 215 per year higher than the total expenditure of control households, which implies a better livelihood of the households involved in the project.
Gini index of total expenditure was found to be 0.34 and 0.40 for the CBFC project and control households respectively, which indicate that expenditure was equally distributed among households, but that it is more equally distributed among the CBFC households as compared to the control households. The expenditure inequality difference between the CBFC project and the control sites was 0.06, which implies that the CBFC management system helped to distribute total expenditure more equally among the surrounding communities.
For better management of the floodplain beels, the government may apply a similar policy for better utilization of the resources and for the economic benefits of the beneficiaries. Accountability, sustainable management of the floodplains, proper marketing of fish and equity in the distribution of benefits of the floodplains have proven to increase the productivity and ensure the accessibility of the poor and landless farmers, as long as elite capture is controlled.
Taking all CBFC project lessons into consideration, the Bangladesh government could indeed make some changes to their floodplain /wetland policy in order to accommodate the poor fishers and the landless poor. Policy (re)formulation may be needed for the dissemination of the CBO-based fish culture approach to scale-up its impact. In order to establish the rights of the CBOs (under the leadership of fishers) there is a need for modification of the policy of leasing of public floodplains. The major issues to be included are to bring private and public floodplains under CBO management; to secure government support for the registration of the CBOs and the strengthening of the institution; to guarantee that CBOs obtain long term (10-15 years or more) lease of the public areas of the floodplains as priority; to support small infrastructure constructions in the outlet and inlets of the floodplains; and to develop a functional model for the scaling-up (influencing policy) and scaling-out of the CBO fish culture approach in Bangladesh.
To assess the effectiveness of the scaling-up of the innovation in Community-Based Fish Culture in public and private floodplains, using a CBO to CBO approach will have to be developed with the support and facilitation from formal institutions. This will be considered as the subject of future research.
Interactions between land use and flood management in the Chi River Basin
Kuntiyawichai, K. - \ 2012
Wageningen University. Promotor(en): E. Schultz; S. Uhlenbrook. - [S.l. : S.n. - ISBN 9789461732491 - 213
hoogwaterbeheersing - overstromingen - waterbeheer - landgebruik - rivieren - stroomvlakten - watervoorraden - wiskundige modellen - thailand - flood control - floods - water management - land use - rivers - floodplains - water resources - mathematical models - thailand
The damages and hardships caused by floods and flooding remain an issue and are continuously increasing in the Chi River Basin, Thailand. It is difficult to make an accurate assessment of the costs and consequences associated with floods. However, flood hazards can also be seen as an opportunity, a chance to correct possible flaws and ambiguities in the flood management.
The Chi River system cannot handle the regularly occurring floods, consequently, flooding of the low-lying areas occurs on a regular basis. Therefore, an integrated flood management framework needs to be developed to minimize the negative effects of floods of different magnitude. In response, a hydrological model (SWAT) and a hydraulic (1D/2D SOBEK) model were integrated to simulate floods in detailed way and to analyse the current system. A reliable simulation of the river flows and inundated areas is an essential component of a holistic flood management plan.
The developed modelling framework enabled to analyse the impact of different structural measures such as river normalisation, green river (bypass), and retention basin. In addition, non-structural measures including reservoir operation and spatial land use planning were assessed in their capability to protect people and valuable infrastructure. For each measure, several possible scenarios were tested and evaluated based on economic and technical efficiency criteria to determine the most promising and efficient scenario. However, effective interventions may involve a judicious combination of flood mitigation approaches, rather than reliance on a stand-alone solution. A truly optimum combination of aforesaid measures was then chosen since it could considerably reduce flood extent and its damage.
Finally, the study illustrates the effects of land use changes on floods, which indicated little or no significant potential impact on flood regime at river basin level, but rather at sub-basin scale. This finding is important for a better understanding of the scale and direction of impacts of developments in the future. Integrated land use planning was shown to be an essential component of a comprehensive flood management framework.
Leren van de Wolga; vloedvlaktes blijken belangrijk voor vis
Nagelkerke, L.A.J. - \ 2011
Visionair : het vakblad van sportvisserij Nederland 20 (2011). - ISSN 1569-7533 - p. 16 - 19.
stroomvlakten - vissen - habitats - rusland - floodplains - fishes - habitats - russia
Eind 2007 verscheen in Visionair een artikel over een uniek onderzoek naar de relatie tussen vloedvlaktes en vis in de Russchische Wolga. Inmiddels is de eerste fase succesvol afgesloten. De onderzoeksresultaten bieden een schat aan informatie over de biologie en het beheer van riviervissen.
Floods and fish : recruitment and distribution of fish in the Volga River floodplain
Górski, K. - \ 2010
Wageningen University. Promotor(en): Johan Verreth, co-promotor(en): Leo Nagelkerke; Erwin Winter. - [S.l. : S.n. - ISBN 9789085858157 - 223
rivieren - stroomvlakten - overstromingen - vissen - populatie-aanwas - distributie - populatiedynamica - visbestand - rusland - visserijbiologie - hydrogeologie - aquatische ecosystemen - rivers - floodplains - floods - fishes - recruitment - distribution - population dynamics - fishery resources - russia - fishery biology - hydrogeology - aquatic ecosystems
Natural river floodplains are among the most diverse and productive ecosystems on Earth and provide key habitats for foraging, spawning and as a nursery for many riverine fish species. Periodic flooding plays a principal role in the ecological processes in floodplain systems resulting in high productivity and diversity, as formulated in the Flood Pulse concept (FPC, a major conceptual framework for understanding the hydro–ecological processes operating in river-floodplain systems). However, little progress has been made in exploring the FPC over larger spatial scales due to lack of empirical data. The Volga-Akhtuba floodplain (Russian Federation) is still relatively undisturbed, while in Europe and North-America about 90% of floodplains have effectively been lost. This thesis provides a quantitative assessment of the FPC by (1) analyzing flood pulse dynamics in response to changes in river flow regime on various spatial and temporal scales and (2) relating these to recruitment success of riverine fish species that use the floodplain; and (3) identifying the hydro-geomorphic variables that are most involved shaping fish abundance and distribution in the floodplain. The results obtained demonstrate that the flood pulse magnitude in the lower Volga has noticeably decreased due to damming of the Volga upstream from the Volga-Akhtuba floodplain. Still, in spite of this hydrological control, considerable year-to-year variation in flood magnitude and timing has remained. Therefore fish populations in the floodplain still depend on variations in the year-to-year flow regime. Moreover, spring temperature and its match with flooding control the recruitment of young fish at the end of the growing season. However, the main sources of spawning stocks in the large-scale Volga-Akhtuba floodplain originate from local floodplain populations and not from the main river channels. Spatial heterogeneity of hydro-geomorphic attributes of the floodplain water bodies is highly significant for structuring fish abundance and distribution in the floodplain. Therefore, even under changing environmental and social circumstances, it is essential to preserve flood dynamics, which is fundamental not only for fish recruitment success but also governs fish distribution and diversity in the floodplain.
Nematode-based risk assessment of mixture toxicity in a moderately polluted river floodplain in The Netherlands
Vliet, P.C.J. van; Goede, R.G.M. de - \ 2008
Science of the Total Environment 406 (2008)3. - ISSN 0048-9697 - p. 449 - 454.
stroomvlakten - zware metalen - nematoda - rivieren - indicatoren - graslanden - verontreiniging - toxiciteit - gelderland - land van maas en waal - waal - floodplains - heavy metals - nematoda - rivers - indicators - grasslands - pollution - toxicity - gelderland - land van maas en waal - river waal - soil - sensitivity - communities - cadmium - metals - forest
Heavy metal polluted soils usually contain mixtures of different metals, whereas legislation is derived from concentrations of individual metals. The mixture toxicity of the Dutch floodplain Afferdensche and Deestsche Waarden was estimated to be high (msPAF ranged from 67¿94%). Analyses of nematode community based bioindicators (Maturity Index, taxonomic diversity, trophic groups, multivariate analysis, DoFT-sentinels) were used to determine the ecological effects of the mixture toxicity in the floodplain soil. None of the indices indicated direct effects of heavy metals on the nematode community. This can be explained by the high adsorption of heavy metals on organic matter and clay particles resulting in a low bioavailability, and questions the estimation of the toxicity based on total concentrations of heavy metals in such environments. The nematode fauna showed great seasonal variation, which most probably was related to the temporal inundation of the floodplain.
Aeolian and fluviolacustrine landforms and prehistoric human occupation on a tectonically influenced floodplain margin, the Méma, central Mali
Makaske, B. ; Vries, E. de; Tainter, J.A. ; McIntosh, R.J. - \ 2007
Netherlands journal of geosciences 86 (2007)3. - ISSN 0016-7746 - p. 241 - 256.
eolische afzettingen - geomorfologie - geologische sedimentatie - rivieren - landschap - stroomvlakten - mali - aeolian deposits - geomorphology - geological sedimentation - rivers - landscape - floodplains - mali - niger - holocene - africa
The Méma is a semi-arid region in central Mali with a rich archaeological heritage indicating the former existence of large urban settlements. The archaeological data suggest millennia of occupation history of the Méma preceding relatively sudden abandonment by the 14th or 15th century AD. Population numbers have remained low since then and today's human presence in the area is sparse and largely mobile. Geomorphologically, the Méma can be characterized as a graben hosting various generations of aeolian landforms and (presently mostly dry) interdunal channels and lakes, linked to the neighbouring Inland Niger Delta floodplain. Given this setting, and the variability of the Sahelian climate, climatic contributions to the region's sudden abandonment are likely. A geomorphological survey of the region, and interpretation of the observed geomorphological record in terms of climatic history, aimed at providing a basis for understanding the intensive occupation and subsequent abandonment of the Méma. The results of this study underscore dramatic Holocene climatic variability, leading to the region's present geomorphological diversity, but also suggest that neotectonic movements constitute an important additional cause of regional desiccation. Both may have encouraged prehistoric people to abandon the Méma after a long period of occupation.
Bioaccumulation of persistent organic pollutants from floodplain lake sediments: linking models to measurement
Moermond, C.T.A. - \ 2007
Wageningen University. Promotor(en): Bart Koelmans, co-promotor(en): J.J.G. Zwolsman. - [S.l.] : S.n. - ISBN 9789085047056 - 192
sedimentmaterialen - stroomvlakten - ecotoxicologie - aquatische ecosystemen - bioaccumulatie - persistente organische verontreinigende stoffen - sedimentary materials - floodplains - ecotoxicology - aquatic ecosystems - bioaccumulation - persistent organic pollutants
The main research questions of this research were (1) what is the extent and nature of bioavailability of sediment-bound polychlorobiphenyls (PCBs) and polyaromatic hydrocarbons (PAHs) and (2) what are the effects of lake ecosystem structure on fate and bioaccumulation of PCBs and PAHs. Fast-desorbing fractions in the sediment of floodplain lakes were estimated by the 6-h Tenax-extractable fractions with a correction factor. These fractions varied between 1 and 40% and did not show a clear trend with log KOW. This means that contaminants in these sediments were available, but to a smaller extent than total concentrations would suggest. The 6-h Tenax extractable concentration often correlated better with bioaccumulation than the total extractable concentration in sediment. Despite the reduced availability, benthivorous fish and invertebrates in floodplain lakes still rapidly accumulated substantial amounts of PCBs. PAHs were accumulated relatively less because PAHs were relatively less available than PCBs due to their stronger sorption to carbonaceous materials, also referred to as soot or black carbon. For fish, metabolic transformation caused even lower PAH concentrations. Contaminants that have been present in the sediment for longer periods of time (years to decades), were less available for Tenax extractions as well as for uptake by biota in different parts of the food web than contaminants that were recently added. Thus, aging may translate directly into reduced uptake at higher trophic levels. Nutrient additions in enclosures with benthivorous fish had a positive effect on PCB accumulation by these fish. Measured bioaccumulated concentrations of PCBs and PAHs in invertebrates in flood plain lakes were not influenced greatly by seasonal effects or ecological structure. Although effects were statistically significant, their magnitude in terms of accumulation factors was small, which may have been caused by the similar sediment composition and bioavailability of contaminants in our systems. Differences between compounds were much larger than differences due to ecosystem structure, seasons, or species composition. As for total masses of PCBs and PAHs in certain compartments however, lake ecosystem structure appeared to have a large influence on the biomass of biota and therefore also on the mass distribution of PCBs and PAHs in biotic compartments. Thus, changes in ecosystem structure strongly influenced PCB and PAH dynamics, although concentrations within the biotic compartments were not significantly influenced by biotic biomass. As for bioaccumulation modelling, when aquatic exposure concentrations were quantified accounting for sorption to carbonaceous materials, model results improved substantially. Including metabolic transformation and sediment uptake in the model accounted for a further improvement of the model fit. Implications are discussed for food chain bioaccumulation modeling, bioavailability assessment, sediment policy making and floodplain lake management.
Het voorkomen van loopkevers binnen een vegetatiegradiënt in de Millingerwaard (Coleoptera, Carabidae)
Verdonschot, R.C.M. ; Noordijk, J. ; Sykora, K.V. ; Schaffers, A.P. - \ 2007
Entomologische Berichten 67 (2007)3. - ISSN 0013-8827 - p. 82 - 91.
habitatselectie - multivariate analyse - stroomvlakten - vegetatie - coleoptera - insecten - gelderse poort - habitat selection - multivariate analysis - floodplains - vegetation - coleoptera - insects - gelderse poort
Op basis van een vangpotonderzoek wordt de relatie tussen het voorkomen van loopkeversoorten, abiotische factoren en de vegetatie beschreven. Het onderzoek werd uitgevoerd in 2004 in de Millingerwaard. Er kan geconcludeerd worden dat bepaalde loopkeversoorten alleen bij een bepaald type vegetatie voorkomt
Identifying the appropriate scales to model nitrogen flows from land to water
Dumont, E.L. - \ 2007
Wageningen University. Promotor(en): Rik Leemans; A. Stein, co-promotor(en): Carolien Kroeze; Lex Bouwman; Evert Jan Bakker. - [S.l.] : S.n. - ISBN 9789085046516 - 142
stikstof - stroming - modellen - land - water - stroomvlakten - rivieren - kustwateren - nitrogen - flow - models - land - water - floodplains - rivers - coastal water
Human activities cause flow of nitrogen (N) from terrestrial to aquatic systems. This has many serious consequences that need to be alleviated. Understanding and anticipation of N flow to aquatic systems can be achieved by modeling. Several models have been developed but one of their major weaknesses is the use of inappropriate scales. Therefore, the objective of this thesis is to increase our ability to identify appropriate spatial and temporal scales for N-flow models in a transparent and comprehensive way. In order to meet this objective, the following sub-objectives are addressed:
II. To develop aframeworkfor identifying the appropriate spatial and temporal scales of N-flow models.
III To apply this framework to a model of global N flow.
IV To assess the applicability of this framework to models of N flow between floodplains and rivers.First, a spatially explicit, global model for predicting dissolved inorganic nitrogen export (DIN) by rivers to coastal waters (NEWS-DIN) is developed. NEWS-DIN models DIN export from watersheds to coastal waters as a function of N inputs to watersheds including manure N, fertilizer N, atmospheric N deposition, and biological N 2 fixation, as well as sewage. NEWS-DIN also includes retention and loss terms, including N retention in river networks, N retention in dammed reservoirs, N loss via consumptive water use,denitrificationin rivers, and N loss via harvesting and grazing. For global watersheds DIN yields are calculated ranging from 0.0004 to 5217 kg N km -2 y -1 with the highest DIN yields occurring in Europe and
Avoidance of polycyclic aromatic hydrocarbon-contaminated sediments by the freshwater invertebrates Gammarus pulex and Asellus aquaticus
Lange, H.J. de; Sperber, V. ; Peeters, E.T.H.M. - \ 2006
Environmental Toxicology and Chemistry 25 (2006)2. - ISSN 0730-7268 - p. 452 - 457.
waterverontreiniging - sediment - stroomvlakten - besmetters - toxicologie - polycyclische koolwaterstoffen - waterinvertebraten - waterdieren - gammarus pulex - asellus aquaticus - waterbodems - ecotoxicologie - water pollution - sediment - floodplains - contaminants - toxicology - polycyclic hydrocarbons - aquatic invertebrates - aquatic animals - gammarus pulex - asellus aquaticus - water bottoms - ecotoxicology - oligochaete lumbriculus-variegatus - induced community tolerance - rhine-meuse delta - pollution - toxicity - amphipod - metals - food - earthworm - responses
Contamination of sediments is a serious problem in most industrialized areas. Sediments are often contaminated with trace metals and organic contaminants like polycyclic aromatic hydrocarbons (PAHs) and polychlorinated biphenyls (PCBs). Bioassays are often used to determine the effect of contaminants on biota. However, survival or growth may not be the most sensitive endpoints. Behavioral changes often occur at much lower concentrations. Our study aimed to assess the effect of PAHs on habitat choice of two common freshwater invertebrates, the amphipod Gammarus pulex and the isopod Asellus aquaticus. We spiked clean field sediment with a mixture of four PAHs, fluoranthene, pyrene, chrysene, and benzo[k]fluoranthene, to a total concentration of 30 mg PAH/kg dry weight. Both species were offered a choice between PAH-spiked sediments and clean sediments in laboratory experiments. Results show that both species avoid PAH-spiked sediment. Origin of the population, either from a clean reference site or from a polluted site, did not affect habitat choice of either species
Trace metals in floodplain lake sediments : SEM/AVS as indicator of bioavailability and ecological effects
Griethuysen, C. van - \ 2006
Wageningen University. Promotor(en): Bart Koelmans. - [S.l. ] : S.n. - ISBN 9789085043652 - 223
sporenelementen - metalen - stroomvlakten - meren - sediment - verontreinigende stoffen - waterverontreiniging - methodologie - ecologie - risicoschatting - waterkwaliteit - nederland - land van maas en waal - trace elements - metals - floodplains - lakes - sediment - pollutants - water pollution - methodology - ecology - risk assessment - water quality - netherlands - land van maas en waal
This thesis addresses the geochemical aspects of AVS (Acid Volatile Sulfide) and SEM (Simultaneously Extracted Metals) in floodplain lake sediment, its spatial distribution in floodplain lakes and dynamics over time, the link with effects on single species (bioassays), as well as the impact of excess SEM on the in situ benthic community, in one consistent methodological approach. Using this approach the SEM-AVS concept is thus evaluated on various levels from geochemical through ecotoxicology towards ecology. Furthermore, the aspect of spatial and temporal variability is addressed. For the case studies in the field, several floodplain lakes located in the floodplain area Afferdensche and Deestsche Waarden along the Waal branche of the Rhine were selected. Occasionally, this selection was extended towards other floodplain lakes along the Rhine branches. The main goal of this research is a) to explore the actual risks of trace metals to benthic communities in floodplain systems and b) to evaluate the SEM-AVS concept as a tool to assess bioavailable concentrations of trace metals in dynamic floodplain sediment
Lilian van den Aarsen in de Havikerpoort; schakelen tussen de regio en de wereld van Den Haag
Hazeleger, B. ; Vos, C.C. - \ 2006
Landschap : tijdschrift voor landschapsecologie en milieukunde 23 (2006)2. - ISSN 0169-6300 - p. 70 - 74.
stroomvlakten - landschap - ecologische hoofdstructuur - veluwe - uiterwaarden - landscape - regional planning - ecological network - veluwe - river forelands
Op pad in haar favoriete landschap bij Middachten schetst Lilian van Aaarsen (LNV) met veel overtuiging hoe ze schakelend achtjes draait tussen de concrete inrichting in de regio en het Haagse Tweede-Kamer-Land. Het artikel bevat uitleg over de Havikerpoort: de ecologische verbinding tussen Veluwe en uiterwaarden van de IJssel
|Dynamiek versluiert; veldeffecten van metalen in dynamische ecosystemen
Klok, C. - \ 2006
Bodem 16 (2006)3. - ISSN 0925-1650 - p. 120 - 121.
ecosystemen - toxicologie - aardwormen - bodemfauna - overstromingen - stroomvlakten - zware metalen - ecotoxicologie - ecosystems - toxicology - earthworms - soil fauna - floods - floodplains - heavy metals - ecotoxicology
Deze bijdrage richt zich op de invloed van overstroming op de kans dat effecten van vervuiling zichtbaar worden op regenwormpopulaties
Effects of flooding on germination, establishment and survival of woody species; a field and modeling study on the floodplains of the river Rhine
Kramer, K. ; Nijhof, B.S.J. ; Vreugdenhil, S.J. ; Werf, D.C. van der; Wyngaert, I.J.J. van den; Armbruster, J. ; Späth, V. ; Siepmann-Schinker, D. - \ 2006
Wageningen : Alterra (Alterra-rapport 1345) - 72
inundatie - kieming - vestiging - overleving - oeverbossen - stroomvlakten - wateropslag - hoogwaterbeheersing - houtachtige planten - nederland - duitsland - bomen - rijn - flooding - germination - establishment - survival - riparian forests - floodplains - water storage - flood control - woody plants - netherlands - germany - trees - river rhine
Climate change results in higher water levels and therefore more frequent flooding and longer inundation of the floodplains of the river Rhine. Retention basins are installed in Germany and anticipated in the Netherlands to reduce peak flows and to prevent loss of property. In Germany, many of the retention basins are covered with forests that have experienced few floodings and that may be severely damaged by an extensive flood. In the Netherlands, the allocation of retention basins provides opportunities for new forest development. In both cases, knowledge is required on the effects of flooding on germination, establishment and survival of woody species to support the selection of retention basins. We analyzed the effects of flooding regimes on germination, establishment and survival of both saplings and adult trees, using analyzing available data; by collecting observational data; by performing field experiments; and by integrating this knowledge in a simulation model. We found clear differences between species in their response to flooding characteristics. The model is available for future studies on selection of retention basins
Ecoflood guidelines : how to use floodplains for flood risk reduction
Blackwell, M.S.A. ; Maltby, E. ; Gerritsen, A.L. ; Haasnoot, M. ; Hoffmann, C.C. ; Kotowski, W. ; Leenen, E.J.T.M. ; Okruszko, T. ; Penning, W.E. ; Piorkowski, H. ; Platteeuw, M. ; Querner, E.P. ; Siedlecki, T. ; Swart, E.O.A.M. de - \ 2005
[S.l.] : Ecoflood Project - 144
stroomvlakten - hoogwaterbeheersing - overstromingen - risicovermindering - richtlijnen (guidelines) - rivieren - europa - risicobeheersing - floodplains - flood control - floods - risk reduction - guidelines - rivers - europe - risk management
The main objective of these guidelines is to promote the use of floodplains as natural flood defence measures, while at the same time optimising other compatible functions and values through conservation and restoration. It is intended that these guidelines will be used as a tool primarily by policy-makers and decision-makers who are aware of the potential advantages of floodplain restoration and management in the role of flood control, but may benefit from comprehensive guidance on assessing, initiating, funding and carrying-out such schemes as well as information on the other functions floodplains can perform. It is also intended that they will be an accessible source of information for a wide range of stakeholders with an interest in floodplain management. Case studies are provided to illustrate the wide range of schemes that can be carried out and the degrees of success that have been achieved. Case studies from the Netherlands are: 1. Meinerswijk, Rhine; 2. Zandmaas and Grensmaas, Meuse; 3. Gamerensche Waard, Lower Rhine; 4. Afferdensche en Deestsche Waarden, Lower Rhine
|Rehabilitating large regulated rivers; lowland river rehabilitation conference; Wageningen, 29 september - 3 oktober 2003
Buijse, A.D. ; Klijn, F. ; Leuven, R.S.E.W. ; Middelkoop, H. ; Schiemer, F. ; Thorp, J.H. ; Wolfert, H.P. - \ 2005
Stuttgart (Germany) : Schweizerbart (Archiv für Hydrobiologie Suppl. vol. 155, no. 1-4) - 738
stroomvlakten - herstel - rivierregulering - rivieren - hydrobiologie - floodplains - rehabilitation - river regulation - rivers - hydrobiology
Regulating rivers has reduced the natural dynamic processes, altered the landscape and its biodiversity. Along large rivers that serve manifold functions, rehabilitation attempts have recovered stretches or certain features, but complete restoration probably will be a utopia. Key questions of the conference were e.g. how sustainable or effective are we so far; how well did we assess our achievements; what are the costs and benefits, opportunities and constraints, the end-points? More than 50 oral contributions and over 40 posters were presented at the conference, 45 of which, from 14 different countries, are published as peer-reviewed papers in this issue
Macrophyte succession in floodplain lakes : spatio-temporal patterns in relation to river hydrology, lake morphology and management
Geest, G.J. van - \ 2005
Wageningen University. Promotor(en): Marten Scheffer, co-promotor(en): Rudi Roijackers; H. Coops. - s.l. : S.n. - ISBN 9789085041511 - 157
waterplanten - waterorganismen - stroomvlakten - hydrologie - plantensuccessie - vegetatie - patronen - waterstand - rijn - aquatic plants - aquatic organisms - floodplains - hydrology - plant succession - vegetation - patterns - water level - river rhine
Two questions are central to the work in this thesis: 1. What are the factors determining macrophyte composition in floodplain lakes along the Lower Rhine? 2. What advice can be given for design of future water bodies?
Decision Support System for Floodwater Spreading Site Selection in Iran
Kheirkhah Zarkesh, M. - \ 2005
Wageningen University. Promotor(en): Leo Stroosnijder, co-promotor(en): A.M.J. Meijerink; M.A. Sharifi. - Enschede : ITC - ISBN 9789085042563 - 259
hoogwaterbeheersing - inundatie - waterbeheer - besluitvorming - simulatiemodellen - iran - stroomvlakten - overstroomde gronden - beslissingsondersteunende systemen - flood control - flooding - water management - decision making - simulation models - iran - floodplains - flooded land - decision support systems
Keywords: DSS, remote sensing, GIS. spatial multi-criteria evaluation, analytical hierarchy process, floodwater spreading, groundwater recharge, Iran.
Most aquifers of semi-arid Iran suffer from over-exploitation of groundwater for irrigation. It is therefore important to augment the groundwater resource by artificial recharge, using flood waters that flow into salt lakes or in the sea. The recharge schemes consist generally of diversion of part of the flood discharges of ephemeral rivers in small to medium sized catchments onto infiltration basins.
Apart from recharge of groundwater, supporting food production and drinking water supplies, the schemes have other benefits, such as mitigation of flood damages and 'greening of the desert'. Many governments, including the one of Iran, place now much emphasis on increasing the number of floodwater spreading schemes.
A large number of factors play a role in the selection of the most suitable sites for deciding on investment in a scheme. These factors pertain to earth science (geology, geomorphology, soils), to hydrology (runoff and sediment yield, infi!tration and groundwater conditions) and to socio-economic aspects (irrigated agriculture, flood damage mitigation, environment, job creation and so on). Hence, the decision depends on criteria ofdiverse nature.
This thesis deals with developing a Decision Support System (DSS) to assist decisions as to where the most suitable catchments and associated infiltration areas are and to work out options of types of schemes, which are adjusted to the characteristics ofthe selected infiltration area (the site available).
After discussion of the bio-physical setting for flood spreading schemes in the Introduction (Chapter 1), attention is given to the selection ofthe desired approach for multi-criteria evaluation in Chapter 2. The Analytical Hierarchical Processes (AHP) approach was considered to be appropriate for the problem at hand and use was made of the spatial extension of this approach in a GIS environment, after structuring all the major criteria for a flood spreading scheme.
Of key importance is of course the expected infiltration of flood water diverted. For such an a-priori estimate the effect of soil textures in a soil column on infiltration and percolation have to be made, as well as an estimate of the effects of sedimentation of clay and sand in a scheme, as well as effect of inundation depth and flooding frequency. One-dimensional soil modelling was done with the SWAP model. Chapter 3, using two pedo-transfer functions for the hydraulic parameters based on textures. It was found that for coarse textured soils there was reasonable agreement between functions used, but quite some differences were found for the soils containing clay and silt. As expected, recharge efficiency was positively affected by inundation depth and by rapid succession of inundations.
Because simulation results differed, the recharge of the complex and large Sorkhehesar scheme was analysed, by developing a spreadsheet programme to work out depths, areas and duration of inundation. Chapter 4. It was found that the Mnalem-van Genuchten transfer function was the most appropriate one.
Given the large number of ephemeral rivers draining hilly catchments and passing through alluvial areas, is necessary to first use a rapid screening method to obtain zones which contain promising areas, for which the main criteria are applicable. The screening depends heavily on interpretation of remotely sensed images, which have the advantage that various aspects are presented in a synoptic view. The interpretation has to have a firm footing in earth science because runoff and sediment delivery processes have to be estimated in qualitative terms, as well as aquifer properties. A number of examples from Iran have been described in Chapter 5, highlighting the importance of transmission losses.
In order to select the most suitable area among the promising ones, the spatial AHP was applied in the Varamin zone under consideration of a multitude of criteria, in Chapter 6. The difficulty in the application was to develop and specify the preferences that are the base of the relative importance values for all the decision criteria involved at different levels, once the various factors had been estimated using standard hydrological and other methods. The use of the linguistic measures of preferences in the pair-wise comparisons made it possible to implement the full procedure, even though data differed much in nature, consistency and quality. In the Varamin zone, the Chandab catchment and infiltration area came out as the ''most satisfying" area; it had the highest sum of utilities for three of the four objectives and the highest score in a combination scenario.
For the Chandab infiltration site, a spreadsheet model was developed to work out various options with regard to type of scheme (shallow basin or deep basin type) and size of scheme, resulting in the expected volumes of recharge during the lifetime of the scheme by assuming desilting operations. Of the additional benefits, the flood damage mitigation could be expressed in monetary terms, and that benefit had a profound effect on the cost per unit volume of recharge water if one opts for the two large sized scheme designs.
To our knowledge, this study presents for the first time information on costs and benefits of a flood water spreading scheme in Iran in a structured manner of various designs adjusted to a particular site.
The final conclusion (Chapter 8) states that the DSS described here, with its three stages of increasing focus and associated data requirements and with the approach for evaluation using a multitude of criteria of diverse nature, has proven to be applicable and an efficient way to select the most appropriate alternatives for making a choice for investment in a flood spreading scheme. Although the emphasis was on Iranian conditions, the DSS is essentially of generic nature and may be applied ~ mutatis mutandis- to other semi arid regions.
Modeling of the solid-solution partitioning of heavy metals and arsenic in embanked flood plain soils of the rivers Rhine and Meuse
Schröder, T.J. ; Hiemstra, T. ; Vink, J.P.M. - \ 2005
Environmental Science and Technology 39 (2005)18. - ISSN 0013-936X - p. 7176 - 7184.
bodemverontreiniging - zware metalen - arsenicum - stroomvlakten - rivieren - geochemie - nederland - bodemkwaliteit - rijn - maas - soil pollution - heavy metals - arsenic - floodplains - rivers - geochemistry - netherlands - soil quality - river rhine - river meuse - ray-absorption spectroscopy - hydrous manganese oxide - natural organic-matter - goethite alpha-feooh - biotic ligand model - ion-binding - surface complexation - contaminated soils - pb(ii) sorption - acute toxicity
The aim of this study is to predict the solid-solution partitioning of heavy metals in river flood plain soils. We compared mechanistic geochemical modeling with a statistical approach. To characterize the heavy metal contamination of embanked river flood plain soils in The Netherlands, we collected 194 soil samples at 133 sites distributed in the Dutch part of the Rhine and Meuse river systems. We measured the total amounts of As, Cd, Cr, Cu, Ni, Pb, and Zn in the soil samples and the metal fraction extractable by 2.5 mM CaCl2. We found a strong correlation between heavy metal contamination and organic matter content, which was almost identical for both river systems. Speciation calculations by a fully parametrized model showed the strengths and weaknesses of the mechanistic approach. Cu and Cd concentrations were predicted within one log scale, whereas modeling of Zn and Pb needs adjustment of some model parameters. The statistical fitting approach produced better results but is limited with regard to the understanding it provides. The log RMSE for this approach varied between 0.2 and 0.32 for the different metals. The careful modeling of speciation and adsorption processes is a useful tool for the investigation and understanding of metal availability in river flood plain soils
Flood forests of the inner Niger delta, mali; past, present, and future
Beintema, A.J. ; Fofana, B. ; Faye, A. ; Huiskes, H.P.J. - \ 2005
Wageningen : Alterra (Alterra-rapport 1316) - 52
laagland bossen - stroomvlakten - bossen - west-afrika - vogels - biodiversiteit - delta's - rivieren - bottomland forests - floodplains - forests - west africa - birds - biodiversity - deltas - rivers
Flood forests have a special place in the Inner Niger Delta, Mali. They have a great economic value for the local populations, and are hotspots of biodiversity in the delta. This report reviews the status of all flood forests in the Inner Niger Delta, Mali, that are presently known, or have been known to exist in the past. In total, the status of 39 sites has been evaluated. Of the remaining 37 sites, 8 have been totally lost and cleared, while 22 have been severely degraded, losing their function for colonial waterbirds. This leaves 7 forests in a more or less healthy state some of which host very large mixed colonies of waterbirds. Of the severely degraded forests, 8 are included in restoration projects by Wetlands International and IUCN. Of these 8, two still hold small numbers of breeding birds, which means that are forests which have breeding birds and can be considered future nuclei if they are further developed. Based on this, and on a judgement on the other forests, a strategic plan has been developed for the restoration of a functional network of flood forests in the delta.
Water-level fluctuations affect macrophyte richness in floodplain lakes
Geest, G.J. van; Wolters, H. ; Roozen, F.C.J.M. ; Coops, H. ; Roijackers, R.M.M. ; Buijse, A.D. ; Scheffer, M. - \ 2005
Hydrobiologia 539 (2005)1. - ISSN 0018-8158 - p. 239 - 248.
waterplanten - stroomvlakten - vegetatie - meren - rivieren - biodiversiteit - plantensuccessie - nederland - waterstand - aquatische ecosystemen - rijn - aquatic plants - floodplains - vegetation - lakes - rivers - biodiversity - plant succession - netherlands - water level - aquatic ecosystems - river rhine - shallow eutrophic lakes - aquatic plant diversity - long-term - river floodplains - seed dispersal - germination - connectivity - channels - dynamics
The characteristic ecology of floodplain lakes is in part due to their relatively strong water-level fluctuations. We analyzed the factors determining water-level fluctuations in 100 floodplain lakes (during non-flooded conditions) in the active floodplains of the Lower Rhine in the Netherlands. Furthermore, we explored the relationship between water-level fluctuations and macrophyte species richness, and analyzed the suitability of artificially created lakes for macrophyte vegetation. During non-flooded conditions along the Rhine, lake water-level fluctuations are largely driven by groundwater connection to the river. Hence, water-level fluctuations are largest in lakes close to the main channel in strongly fluctuating sectors of the river and smallest in isolated lakes. Additionally, water-level fluctuations are usually small in old lakes, mainly due to reduced groundwater hydraulic conductivity resulting from accumulated clay and silt on the bottom. Species richness of floating-leaved and emergent macrophytes was reduced at both small and large water-level fluctuations, whereas species richness of submerged macrophytes was reduced at small water-level fluctuations only. In addition, species richness of submerged macrophytes was higher in lakes that experienced drawdown, whereas no similar pattern was detected for floating-leaved and emergent macrophytes. The decline in amplitude of lake water-level with lake age implies that the number of hydrologically dynamic lakes will decrease over time. Therefore, we suggest that excavation of new lakes is essential to conserve the successional sequence of floodplain water bodies including conditions of high biodiversity. Shallow, moderately isolated, lakes with occasional bottom exposure have the highest potential for creating macrophyte-rich floodplain lakes along large lowland rivers. The water-level regime of such lakes can in part be designed, through choice of the location along the river, the distance away from the river and the depth profile of the lake.
Temporal variation of trace metal geochemistry in floodplain lake sediment subject to dynamic hydrological conditions
Griethuysen, C. van; Luitwieler, M. ; Joziasse, J. ; Koelmans, A.A. - \ 2005
Environmental Pollution 137 (2005)2. - ISSN 0269-7491 - p. 281 - 294.
zware metalen - geochemie - meren - oppervlaktewater - waterverontreiniging - stroomvlakten - hydrologie - nederland - gelderland - land van maas en waal - heavy metals - geochemistry - lakes - surface water - water pollution - floodplains - hydrology - netherlands - gelderland - land van maas en waal - acid-volatile sulfide - fresh-water sediments - elements - estuary - solids - avs
Climate change and land use may significantly influence metal cycling in dynamic river systems. We studied temporal variation of sediment characteristics in a floodplain lake, including concentrations of dissolved organic carbon, acid volatile sulfide and trace metals. The sampling period included a severe winter inundation and a dramatic water level drop during summer. Temporal changes were interpreted using multivariate analysis and chemical equilibrium calculations. Metal concentrations in sediment increased with depth, indicating a gradual improvement of sediment quality. In contrast, dissolved metal concentrations were highest in top layers due to mobilization from oxyhydroxides and precipitation with sulfides in deeper layers. Inundation had a mobilizing effect as it stimulated resuspension and oxygenation of sediment top layers. Water table lowering combined with organic matter decomposition led to immobilization due to sulfide formation. The chemistry of the sediments was consistent with model calculations, especially for macro-elements. The results illustrate the importance of seasonality for metal risk assessment.
Succession of aquatic vegetation driven by reduced water-level fluctuations in floodplain lakes
Geest, G.J. van; Coops, H. ; Roijackers, R.M.M. ; Buijse, A.D. ; Scheffer, M. - \ 2005
Journal of Applied Ecology 42 (2005)2. - ISSN 0021-8901 - p. 251 - 260.
meren - plantensuccessie - stroomvlakten - vegetatie - nederland - waterstand - aquatische ecosystemen - rijn - lakes - plant succession - floodplains - vegetation - netherlands - water level - aquatic ecosystems - river rhine - river-margin vegetation - rhone river - plant diversity - flow regulation - boreal rivers - connectivity - channels - macrophytes - disturbance - sediment
In recent years, interest has grown in restoring floodplain function of regulated rivers. Successful rehabilitation of riparian systems requires knowledge of how regulation of river flow affects biodiversity and ecosystem function. The effects of changes in the river's low water-level regime on aquatic ecosystems in floodplains has received little attention so far. The aquatic vegetation of 215 floodplain lakes along the Lower Rhine (the Netherlands) was analysed in relation to lake characteristics and lake water-level fluctuations in 1999–2000. Vegetation composition was related to lake morphology and age, cattle access to the shoreline, the amount of time the river was in flood, and lake sediment area exposed at low water level (drawdown). Surprisingly, vegetation composition was correlated more strongly with lake age and occurrence of drawdown than the amount of time the river was in flood
1. In recent years, interest has grown in restoring floodplain function of regulated rivers. Successful rehabilitation of riparian systems requires knowledge of how regulation of river flow affects biodiversity and ecosystem function. The effects of changes in the river's low water-level regime on aquatic ecosystems in floodplains has received little attention so far. 2. The aquatic vegetation of 215 floodplain lakes along the Lower Rhine (the Netherlands) was analysed in relation to lake characteristics and lake water-level fluctuations in 1999-2000. 3. Vegetation composition was related to lake morphology and age, cattle access to the shoreline, the amount of time the river was in flood, and lake sediment area exposed at low water level (drawdown). Surprisingly, vegetation composition was correlated more strongly with lake age and occurrence of drawdown than the amount of time the river was in flood. 4. In older lakes, water-level fluctuations are reduced due to an accumulation of clay and silt that 'seals' sediment, preventing drawdown during periods of low river levels. Our results suggest that this clay sealing process is a major driving force for aquatic vegetation succession in floodplain lakes along the Lower Rhine, as succession drives from desiccation-tolerant species (e.g. Chara spp.) in young lakes to desiccation-sensitive species (e.g. Nuphar lutea) in old lakes. 5. Water levels were stable in lakes along a river branch that was impounded below mean flow only. Here, the original low water-level regime has been replaced by an artificial regime with higher water levels than would be expected naturally. Consequently, in these lakes drawdown was rare or absent, and the aquatic macrophyte vegetation was characterized by low species richness and frequent dominance by the invasive species Elodea nuttallii. 6. Synthesis and applications. Our results show that stabilization of river water levels during low flow may negatively affect vegetation composition and succession in floodplain lakes adjacent to these rivers. A management scheme including incidental temporary lowering of the river water level, which results in drawdown of floodplain lakes, would enhance the ecological status of those rivers with stabilized water levels during low flow.
Analyzing the causes for the persistence of chironomids in flood plain lake sediments
Haas, E.M. de; Haaren, R. van; Koelmans, A.A. ; Kraak, M.H.S. ; Admiraal, W. - \ 2005
Archiv für Hydrobiologie 162 (2005)2. - ISSN 0003-9136 - p. 211 - 228.
sediment - verontreinigende stoffen - chironomus riparius - benthos - waterverontreiniging - stroomvlakten - zware metalen - meren - biotesten - nederland - ecotoxicologie - waterbodems - rijn - waal - sediment - pollutants - chironomus riparius - benthos - water pollution - floodplains - heavy metals - lakes - bioassays - netherlands - ecotoxicology - water bottoms - river rhine - river waal - quality triad approach - benthic invertebrates - community composition - marine sediment - riparius larvae - toxicity - diptera - river - deformation
The aim of the present study was to analyse the causes for the absence and persistence of chironomids in sediments with a complex pollution history. Observations on the benthic community composition in floodplain lake sediments of the River Rhine, differing in contaminant level and food quality, were combined with laboratory and in situ bioassays, using the midge Chironomus riparius as a model species. The positive relation between food quality and the diversity of the communities indicated that food quality is an important factor regulating benthic community composition, overriding the potential effects of contaminants. Nevertheless, in sediments with high contaminant levels, high densities of species classified as 'pollution-tolerant', such as Chironomus sp., were observed. The laboratory bioassays verified that the contaminant concentrations in these sediments had no direct effect on survival and growth of C. riparius, although higher contaminant concentrations in the sediment resulted in a higher incidence of mentum deformities. Also, the high growth rate of C. riparius in the in situ enclosures in two of the most contaminated sediments indicated chemical stress and mentum deformities did not exclude rapid growth. This observation agrees with the abundance of the resident pollution-tolerant chironomids of the Chironomus plumosus group. In addition, the in situ bioassay pointed out that predation on chironomids added to the field enclosures was significant and is also an important factor in regulating the abundance of chironomids. In sediments with the highest food quality and low levels of contaminants the opportunistic chironomids may have been outcompeted by benthic invertebrate taxa that are not able to persist at more contaminated sites. It is concluded that tolerance of opportunistic chironomids, such as Chironomus sp., combined with their rapid rate of development, enables them to persist in contaminated sediments that are organically enriched avoiding competition with other invertebrates
Edelherten in de Gelderse Poort : haalbaarheidsstudie
Groot Bruinderink, G.W.T.A. ; Lammertsma, D.R. ; Kuiters, A.T. ; Griffioen, A.J. ; Kuipers, H. - \ 2005
Wageningen : Alterra (Alterra-rapport 1153) - 96
wildbeheer - cervus elaphus - edelherten - stroomvlakten - introductie - vegetatie - nederland - monitoring - ecologische hoofdstructuur - gelderland - gelderse poort - wildlife management - cervus elaphus - red deer - floodplains - introduction - vegetation - netherlands - monitoring - ecological network - gelderland - gelderse poort
De Gelderse Poort is een grote eenheid natuur die in potentie een belangrijk onderdeel vormt van een robuuste ecologische verbindingszone voor edelherten tussen de Veluwe en het Maaswoud. Dit rapport presenteert een werkplan voor een proef met edelherten in dit gebied. Belangrijke aspecten van deze proef zijn: het terreingebruik, de gevolgen van hoogwater en de effecten op de vegetatie. In dit laatste zit besloten de relatie met de veiligheid van de rivier, in de zin van het vermogen tot waterafvoer. Ook de gezondheid en het welzijn van de dieren worden gemonitord. Voorgesteld wordt om de proef op twee locaties uit te voeren: de Groenlanden/Bisonbaai en de Millingerwaard. De resultaten van de proef zijn van belang bij de afweging of de ecologische verbindingszone kan worden gerealiseerd. Daarom moeten zij in dat perspectief kunnen worden geïnterpreteerd. Om die reden wordt in afzonderlijke hoofdstukken ingegaan op, in volgorde: de leefwijze van het edelhert, de gewenste startpopulatie, aspecten van gezondheid en welzijn en de verwachtingen omtrent menukeus en terreingebruik. Het slothoofdstuk gaat in op een groot aantal aspecten die samenhangen met het perspectief van een vrijlevende populatie edelherten.
Groene rivier biedt perspectief : nieuw leven in discussie over waterberging
Wolfert, H.P. - \ 2004
Boomblad 16 (2004)2. - ISSN 0924-0101 - p. 4 - 5.
waterbeheer - wateropslag - rivieren - stroomvlakten - ruimtelijke ordening - landgebruik - gelderland - uiterwaarden - physical planning - land use - water management - water storage - rivers - floodplains - gelderland - river forelands
Alterra-onderzoeker ontwierp voor het knooppunt Arnhem-Nijmegen (KAN-gebied) een nieuwe, groene rivier die in de toekomstige behoefte aan waterberging voorziet. Dit plan dat samen met WL Delft Hydraulics is opgesteld, heeft ook mogelijkheden in zich voor luxe woningen, natuur, recreatie en extensieve landbouw
Klimaatsverandering en functionele plantengroepen in wetlands; uitwerking functionele plantengroepen voor rivierdynamiek
Nijhof, B.S.J. ; Wamelink, G.W.W. ; Runhaar, J. - \ 2004
Wageningen : Alterra (Alterra-rapport 1121) - 84
vegetatie - wetlands - stroomvlakten - klimaatverandering - vegetatietypen - soorten - vegetation - wetlands - floodplains - climatic change - vegetation types - species
Bij het voorspellen van effecten van ingrepen op vegetaties wordt vaak uitgegaan van indicatiesystemen gebasseerd op standplaatscondities. Een andere benadering is het voorspellen van voorkomen van soorten op basis van functionele eigenschappen. In populatie-ecologisch onderzoek gericht op successie wordt dit veel toegepast, e.g. de C-S-R-benadering van Grime. Is een dergelijke benadering een vervanging van of een aanvulling op de bestaande indicatiesystemen? Kan de functionele benadering het hiaat in de voorspelling van het effect van dynamische processen in rivieren, welke met de bestaande indiactiesystemen niet of onvoldoende voorspeld kan worden, opvullen? Wat is de voorspellende waarde van de functionele benadering? In literatuuronderzoek en door middel van een experiment wordt getracht deze vragen te beantwoorden.
Sediment pollution and predation affect structure and production of benthic macroinvertebrate communities in the Rhine-Meuse delta, The Netherlands
Lange, H.J. de; Jonge, J. de; Besten, P.J. den; Oosterbaan, J. ; Peeters, E.T.H.M. - \ 2004
Journal of the North American Benthological Society 23 (2004)3. - ISSN 0887-3593 - p. 557 - 579.
waterverontreiniging - waterinvertebraten - zware metalen - sediment - besmetters - stroomvlakten - predatie - toxicologie - nederland - ecotoxicologie - rijn - maas - zuid-holland - water pollution - aquatic invertebrates - heavy metals - sediment - contaminants - floodplains - predation - toxicology - netherlands - ecotoxicology - river rhine - river meuse - zuid-holland - saint-francois quebec - acid volatile sulfide - invertebrate community - toxicological factors - population-dynamics - floodplain lakes - fresh-water - availability - bioavailability - extraction
Most floodplain sediments of the rivers Rhine and Meuse in The Netherlands are moderately polluted with trace metals, polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs), and other chemicals. The effects of these sediment-bound contaminants on the productivity of benthic macroinvertebrates are unclear. Sixteen locations along a pollution gradient were investigated in creeks in the Biesbosch floodplain area. Sediment samples were analyzed for bulk sediment characteristics and contaminants (total and bioavailable concentrations of trace metals, PAHs, and PCBs). Exclosures were used to study the effect of predation by fish and birds on macroinvertebrates. Macroinvertebrates were sampled and identified to species level, and production was estimated from biomass increases inside the exclosures during a 1-mo interval in spring
Most floodplain sediments of the rivers Rhine and Meuse in The Netherlands are moderately polluted with trace metals, polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs), and other chemicals. The effects of these sediment-bound contaminants on the productivity of benthic macroinvertebrates are unclear. Sixteen locations along a pollution gradient were investigated in creeks in the Biesbosch floodplain area. Sediment samples were analyzed for bulk sediment characteristics and contaminants (total and bioavailable concentrations of trace metals, PAHs, and PCBs). Exclosures were used to study the effect of predation by fish and birds on macroinvertebrates. Macroinvertebrates were sampled and identified to species level, and production was estimated from biomass increases inside the exclosures during a 1-mo interval in spring. Benthic macroinvertebrate species richness was negatively affected by sediment contamination. Production of oligochaetes and chironomids was not correlated with levels of contamination, but production of gastropods was negatively correlated with contamination. Environmental variables that reflected food availability (seston and sediment organic C) were positively correlated with contamination. Predation significantly reduced invertebrate biomass, but the effects of predation and sediment contamination were not correlated with each other. Our study suggested that the moderate levels of contamination affected the structure but not the productivity of the benthic macroinvertebrate community, probably because of the counteracting effects of contamination and associated surplus of food.
Integration of ecological aspects in flood protection strategies: defining an ecological minimum
Geilen, N. ; Jochems, H. ; Krebs, L. ; Muller, S. ; Pedroli, G.B.M. ; Sluis, T. van der; Looy, K. van; Rooij, S.A.M. van - \ 2004
River Research and Applications 20 (2004)3. - ISSN 1535-1459 - p. 269 - 283.
hoogwaterbeheersing - stroomvlakten - herstel - ecologie - ruimtelijke ordening - alluviaal land - vegetatie - carabidae - coleoptera - maas - flood control - floodplains - rehabilitation - ecology - physical planning - alluvial land - vegetation - carabidae - coleoptera - river meuse - river health - habitat - biodiversity
Policy makers are confronted with the question of how to combine sustainable flood protection and floodplain rehabilitation in the best possible way. Both topics deal with spatial planning aspects in a range of scales. This question was the starting point for the development of an evaluation method within the IRMA/SPONGE project INTERMEUSE, illustrated on the basis of assumed flood protection strategies in the Meuse river basin (the sponge strategy, the retention strategy, and the floodplain lowering or winter bed strategy). The integration of flood protection and floodplain rehabilitation can be performed on two scale levels that are interrelated: on the regional level the focus is on (large parts of) an entire stream basin; on the local level specific site conditions are taken as starting point. Ecological aspects under study are spatial cohesion of habitats as identified by species population persistence modelling (regional, longitudinal level) and required habitat quality for carabid beetles and for meadow vegetation gradients as assessed by correspondence analysis (local, transversal level). The carabid beetles are taken as indicative for the ecological integrity of the river bed, the meadow vegetation for that of the floodplain. A unifying concept in the evaluation of ecological integrity is the ecological minimum: the critical boundary or minimum level of habitat conditions for a potentially good ecological functioning. It is the least acceptable state for a river ecosystem that is still functional to some extent, compared to a natural river ecosystem. The results of this study show clearly that there is a good chance to combine floodplain rehabilitation aims with flood protection activities, both on a local and on an international scale. Although ecological effect assessment and ecological optimizing (referring to a natural reference state) remain basic, additionally the assessment of the ecological minimum helps to define design strategies for integrated flood protection, especially in situations where there is an opportunity for river rehabilitation.
Trace metal availability and effects on benthic community structure in floodplain lakes
Griethuysen, C. van; Baren, J. van; Peeters, E.T.H.M. ; Koelmans, A.A. - \ 2004
Environmental Toxicology and Chemistry 23 (2004)3. - ISSN 0730-7268 - p. 668 - 681.
meren - stroomvlakten - sporenelementen - waterorganismen - waterverontreiniging - rijn - waal - ijssel - aquatic organisms - water pollution - lakes - floodplains - trace elements - river rhine - river waal - river ijssel - acid-volatile sulfide - simultaneously extracted metals - macroinvertebrate community - contaminated sediments - cadmium accumulation - in-situ - invertebrates - toxicity - avs - bioavailability
Effects of contaminants on communities are difficult to assess and poorly understood. We analyzed in situ effects of trace metals and common environmental variables on benthic macroinvertebrate communities in floodplain lakes. Alternative measures of trace metal availability were evaluated, including total metals, metals normalized on organic carbon (OC) or clay, simultaneously extracted metals (SEM), combinations of SEM and acid-volatile sulfide (AVS), and metals accumulated by detritivore invertebrates (Oligochaeta). Accumulated metal concentrations correlated positively with sediment trace metals and negatively with surface water dissolved OC. Sixty-eight percent of the variation in benthic community composition was explained by a combination of 11 environmental variables, including sediment, water, and morphological characteristics with trace metals. Metals explained 2 to 6% of the community composition when SEM — AVS or individual SEM concentrations were regarded. In contrast, total, normalized, and accumulated metals were not significantly linked to community composition. We conclude that examination of SEM or SEM — AVS concentrations is useful for risk assessment of trace metals on the community level.
Immigration: a potential time bomb under the integration of Conservation and Development
Scholte, P. - \ 2003
Ambio 32 (2003)1. - ISSN 0044-7447 - p. 58 - 64.
natuurbescherming - stroomvlakten - herstel - wildbescherming - kameroen - projecten - internationale samenwerking - nederland - nature conservation - wildlife conservation - floodplains - rehabilitation - projects - international cooperation - netherlands - cameroon - africa - biodiversity - management - parks
Integrated Conservation and Development Projects (ICDPs) aim to stimulate conservation without the previous negative experiences for local people, but pay little attention to their long-term impact such as immigration. The rehabilitation of the Logone floodplain in North Cameroon, the core activity of the Waza-Logone ICDP, has led to a 34% increase of sedentary fishermen and a multiple number of temporary fishermen. Whereas livestock pressure tripled, kob antelopes, a key floodplain species, have not increased, reducing their competitiveness. The virtual disappearance of wildlife in nearby Kalamaloue National Park (NP), due to advanced human encroachment forms, is therefore a bleak perspective for Waza NP. Examples from the Central African Republic (CAR), Galapagos, Nigeria and Zimbabwe also showed that in open-access systems, improvement in living standards (development) may stimulate immigration, jeopardizing the stability necessary in protected areas (conservation). Most ICDPs lack demographic monitoring, masking its possible immigration risk. To counter the immigration risk in Waza, a policy was formulated based on local stakeholder categorization and subsequent privileges, resulting in the voluntarily displacement of a village out of Waza NP. It is further recommended that ICDPs should be involved in regional land-use planning and discourage development activities that stimulate immigration.
|Sedimentation on embanked floodplains of the rivers Waal and IJssel
Maas, G.J. ; Makaske, B. - \ 2003
In: Proceedings NCR-days 2002; current themes in Dutch river research / Leuven, R.S.E.W., van Os, A.G., Nienhuis, P.H., Delft : NCR - p. 122 - 124.
geologische sedimentatie - rivieren - stroomvlakten - waal - ijssel - geological sedimentation - rivers - floodplains - river waal - river ijssel
The potential of field spectroscopy for the determination of sediment properties in river floodplains
Kooistra, L. ; Wanders, J. ; Epema, G.F. ; Leuven, R.S.E.W. ; Wehrens, H.R.M.J. ; Buydens, L.M.C. - \ 2003
Analytica Chimica Acta 484 (2003)2. - ISSN 0003-2670 - p. 189 - 200.
bodemeigenschappen - geologische sedimentatie - stroomvlakten - rivieren - spectroscopie - klei - organische stof - nederland - bodemkwaliteit - rijn - soil properties - geological sedimentation - floodplains - rivers - spectroscopy - clay - organic matter - netherlands - soil quality - river rhine - diffuse-reflectance spectroscopy - near-infrared spectroscopy - organic-matter - contamination - calibration - networks
Investigations have shown that visible-near-infrared (VNIR) spectroscopy can accurately determine soil properties under laboratory conditions. In situ assessment of soil properties is of great benefit for several applications, as spectra can be acquired fast and almost continuously. The present study used partial least squares (PLS) regression to establish a relationship between soil reflectance spectra measured under field conditions and the organic matter and clay content of the soil. Spectra were acquired with a fieldspectrometer in a recently reconstructed floodplain along the river Rhine in The Netherlands. Several spectral pre-processing methods were employed to improve the performance and robustness of the models. Results indicate that, under varying surface conditions, field spectroscopy in combination with multivariate calibration does result in a qualitative relation for organic matter (R2=0.45) and clay content (R2=0.43) while under laboratory conditions more accurate results are obtained (R2=0.69 and 0.92, respectively). Soil moisture and vegetation cover had a negative influence on the prediction capabilities for both soil properties. Although the performance of the spectra measured in situ is not as accurate as physical analysis, the accuracy obtained is useful for rapid soil characterisation and remote sensing applications.
Spatial variation of metals and acid volatile sulfide in floodplain lake sediment
Griethuysen, C. van; Meijboom, E.W. ; Koelmans, A.A. - \ 2003
Environmental Toxicology and Chemistry 22 (2003). - ISSN 0730-7268 - p. 457 - 465.
sediment - zware metalen - zwavel - meren - stroomvlakten - ruimtelijke variatie - bodemchemie - nederland - waterbodems - gelderland - geostatistiek - sediment - heavy metals - sulfur - lakes - floodplains - spatial variation - soil chemistry - netherlands - water bottoms - gelderland - geostatistics - simultaneously extracted metals - fresh-water sediments - trace-metals - contaminated sediments - diffusion method - avs - bioavailability - toxicity - cadmium
In risk assessment of aquatic sediments, much attention is paid to the immobilizing effect of acid volatile sulfide (AVS) on trace metals. The difference of AVS and simultaneously extracted metals (SEM) gives an indication of metal availability. In floodplain sediments, where changing redox conditions occur, AVS may play a major role in determining variation in metal availability. The importance of spatial heterogeneity has been recognized in risk assessment of trace-metal-polluted sediments. However, little is known about spatial variation of available metal fractions. We studied spatial variability of sediment, environmental conditions, total contaminant concentrations, and available metals (as SEM-AVS or SEM-AVS/f(OC)) in a floodplain lake. The top 5 cm of sediment was sampled at 43 locations. Data were analyzed with correlation and principal component analysis as well as with geostatistical methods. Trace metal and SEM concentrations and most sediment characteristics were more or less constant within 10%. In contrast, AVS concentrations were much more variable and showed a strong spatial dependence due to differences in lake depth, total sulfur pools, and redox potential (Eh), which resulted in crucial differences in trace-metal availability within the lake. The spatial pattern of SEM-AVS deviates from total or normalized trace-metal patterns. This particularly has implications for risk assessment of sediments prone to dynamic hydrological conditions, where AVS concentrations are also variable in time.
Vegetation abundance in lowland flood plain lakes determined by surface area, age and connectivity
Geest, G.J. van; Roozen, F.C.J.M. ; Coops, H. ; Roijackers, R.M.M. ; Buijse, A.D. ; Peeters, E.T.H.M. ; Scheffer, M. - \ 2003
Freshwater Biology 48 (2003)3. - ISSN 0046-5070 - p. 440 - 454.
waterplanten - hydrologie - meren - eutrofiëring - oppervlaktewater - stroomvlakten - nederland - rijn - aquatic plants - hydrology - lakes - eutrophication - surface water - floodplains - netherlands - river rhine - fresh-water macrophytes - shallow eutrophic lakes - lucius l stocking - submerged macrophytes - biomanipulation tool - sediment composition - biomass - growth - depth - fish
1. We analysed the vegetation structure of 215 lakes in the flood plain of the river Lower Rhine in relation to environmental variables related to hydrological connectivity, lake morphometry, lake age and land use on adjacent land. 2. The frequency distribution of the cover of submerged macrophytes was not normal, implying that submerged macrophytes in any one lake were either scarce or abundant. 3. We observed clear water lakes with submerged macrophyte dominance over a wide range of total P concentration (0.020-0.40 mg total P L-1). 4. Multiple logistic regression indicated that the probability of dominance by submerged macrophytes decreased markedly with the surface area, depth and age of the lakes. The surface area effect occurred independently of the depth. Further, there was a negative relationship between submerged macrophyte dominance and the long-term annual duration of inundation by the river. 5. Nymphaeid cover showed a distinct optimum with respect to mean lake depth, being almost absent in lakes shallower than 0.5 m. In contrast to what was found for submerged plants, the probability of occurrence of nymphaeids increased with lake age. 6. The probability of helophyte occurrence increased with lake age, and decreased with the presence of trees, cattle grazing, surface area, use of manure and mean lake depth. 7. In all cases the critical level of one factor (e.g. mean lake depth) depended on other factors (e.g. surface area or age of lake). Thus, in the present study, small lakes tended to remain dominated by submerged macrophytes up to a greater depth than large lakes, and helophytes colonised smaller lakes in an earlier phase. 8. The effect of inundation by the river was modest. This could be because most of our lakes are rarely inundated during the growing season and experience only moderate current velocities while flooded. 9. The results have practical implications for future management of flood plains for conservation purposes. In new water bodies, macrophyte domination will be promoted if many small shallow lakes, rather than few large deep ones, are excavated.
Waterberging in combinatie met recreatie; "spannend water"
Groot, S. ; Penning, E. ; Kuin, A. ; Jókövi, E.M. - \ 2002
H2O : tijdschrift voor watervoorziening en afvalwaterbehandeling 35 (2002)8. - ISSN 0166-8439 - p. 38 - 39.
waterbeheer - water - opslag - retentie - overstromingsgebieden - inundatie - recreatie - recreatiegebieden - landgebruik - meervoudig landgebruik - landgebruiksplanning - wateropslag - hoogwaterbeheersing - stroomvlakten - overstroomde gronden - noord-holland - meervoudig ruimtegebruik - ruimtelijke ordening - waterberging - water management - water - storage - retention - bottomlands - flooding - recreation - amenity and recreation areas - land use - multiple land use - land use planning - water storage - flood control - floodplains - flooded land - noord-holland
Resultaten van een onderzoek naar de mogelijkheden voor combinatie van de functies waterberging en recreatie in Noord-Holland: waar moet je rekening mee houden; wat voor recreatie komt er; hoe zit het met de waterkwaliteit; hoe kan deze functiecombinatie worden gestimuleerd. Derde artikel in een serie van vier over het project 'Meervoudig ruimtegebruik met waterberging in Noord-Holland'
Vegetation succession in floodplain flats : inventarisation and modelling of measured data and expert judgement
Nijhof, B.S.J. - \ 2002
Wageningen : Alterra (CFR project report 5 / Alterra-rapport 529) - 52
vegetatie - plantensuccessie - stroomvlakten - inundatie - geologische sedimentatie - modellen - plantenecologische groepen - nederland - simulatiemodel - uiterwaarden - vegetation - plant succession - floodplains - flooding - geological sedimentation - models - plant ecological groups - netherlands
Literature study and expert judgement are used to develop succession schemes per vegetation structure type of the Dutch floodplain flats. The occurrence of a vegetation type is said to be mainly related to flooding duration and frequency. The third factor taken into account is the management, for example mowing or grazing. Per vegetation structure type the relation between vegetation types and time span needed for developing from one into another is given.
Belasting van de Afgedamde Maas door bestrijdingsmiddelen; een schatting van de relatieve bijdragen vanuit de uiterwaarden van de Afgedamde Maas en de polders van de Bommelerwaard
Kruijne, R. - \ 2002
Wageningen : Alterra (Alterra-rapport 395) - 91
stroomvlakten - rivieren - pesticiden - gelderland - maas - bommelerwaard - uiterwaarden - bestrijdingsmiddelen - landbouw - milieu - oppervlaktewater - tuinbouw - waterkwaliteit - waterverontreiniging - pesticides - surface water - water pollution - gelderland - river meuse - bommelerwaard - river forelands
Meetgegevens van nutriënten en bestrijdingsmiddelen zijn gebruikt om een beeld te geven van de oppervlaktewaterkwaliteit van de Afgedamde Maas, de Bommelerwaard, en de Maas. Op basis van regionale gegevens over het gebruik van bestrijdingsmiddelen in de fruitteelt-, chrysantenteelt-, rundveehouderij- en akkerbouwsector zijn emissies van stoffen naar het open water van de Bommelerwaard en de uiterwaarden van de Afgedamde Maas berekend. De verdwijning van stoffen uit het oppervlaktewater als gevolg vanafbraak en verdamping is berekend. Het restant van de geëmitteerde hoeveelheid stoffen vormt de belasting van de Afgedamde Maas. De resultaten zijn gepresenteerd op het niveau van deelgebieden en teeltsectoren.
Restoration strategies for river floodplains along large lowland rivers in Europe
Buijse, A.D. ; Coops, H. ; Staras, M. ; Jans, L.H. ; Geest, G. van; Grift, R.E. ; Ibelings, B.W. ; Oosterberg, W. ; Roozen, F.C.J.M. - \ 2002
Freshwater Biology 47 (2002). - ISSN 0046-5070 - p. 889 - 907.
stroomvlakten - rivieren - herstel - rijn - donau - floodplains - rivers - rehabilitation - river rhine - river danube
1. Most temperate rivers are heavily regulated and characterised by incised channels, aggradated floodplains and modified hydroperiods. As a consequence, former extensive aquatic/terrestrial transition zones lack most of their basic ecological functions. 2. Along large rivers in Europe and North America, various floodplain restoration or rehabilitation projects have been planned or realised in recent years. However, restoration ecology is still in its infancy and the literature pertinent to river restoration is rather fragmented. (Semi-) aquatic components of floodplains, including secondary channels, disconnected and temporary waters as well as marshes, have received little attention, despite their significant contribution to biological diversity. 3. Many rehabilitation projects were planned or realised without prior knowledge of their potential for success or failure, although, these projects greatly contributed to our present understanding of river-floodplain systems. 4. River rehabilitation benefits from a consideration of river ecosystem concepts in quantitative terms, comparison with reference conditions, historical or others, and the establishment of interdisciplinary partnerships. 5. We present examples from two large European rivers, the Danube and the Rhine, in which the role of aquatic connectivity has been extensively studied. The Danube delta with its diversity of floodplain lakes across an immense transversal gradient (up to 10 km) serves as a reference system for restoration projects along lowland sections of large rivers such as the Rhine in the Netherlands.
|Intermeuse: the Meuse reconnected; final report of IRMA/SPONGE project No. 9, December 2001
Geilen, N. ; Pedroli, B. ; Looy, K. van; Krebs, L. ; Jochems, H. ; Rooij, S. van; Sluis, T. van der - \ 2001
Delft : NCR - 82
stroomvlakten - hoogwaterbeheersing - herstel - evaluatie - stroomgebieden - rivieren - ruimtelijke ordening - integraal waterbeheer - maas - ecologie - rivierherstel - rivierkunde - Europa - Frankrijk - België - Nederland - Zuid-Holland - Brabant - Limburg - floodplains - flood control - rehabilitation - evaluation - watersheds - rivers - physical planning - integrated water management - river meuse
|Living with floods; resilience strategies for flood risk management and multiple land use in the lower Rhine River basin
Vis, M. ; Klijn, F. ; Rooij, S.A.M. van; Buuren, M. van - \ 2001
Delft [etc.] : WL/Hydraulics [etc.] - 146
overstromingen - rivieren - stroomvlakten - landgebruik - rijn - landschapsecologie - meervoudig ruimtegebruik - overstroming - planologie - ruimtelijke ordening - waterbeheer - waterberging - Overijssel - Gelderland - Utrecht - Waal - IJssel - floods - rivers - floodplains - land use - river rhine
Man-made secondary channels along the river Rhine (The Netherlands); results of post-project monitoring
Simons, J.H.E.J. ; Bakker, C. ; Schropp, M.H.I. ; Jans, L.H. ; Kok, F.R. ; Grift, R.E. - \ 2001
River Research and Applications 17 (2001). - ISSN 1535-1459 - p. 473 - 491.
rivieren - stroomvlakten - herstel - kanalen, klein - ecologie - rijn - rivers - floodplains - rehabilitation - channels - ecology - river rhine
Owing to river regulation in the past and intensive farming, the ecological value of the floodplains of the River Rhine in The Netherlands has decreased dramatically. One way to restore riverine biotopes is to create permanently flowing channels in the floodplain. Along the River Waal, the main branch of the Lower River Rhine, two such secondary channels have been created since 1994. A post-project monitoring programme of 5 years was set up, which included hydrological, morphological and ecological parameters. This article focuses on the monitoring of aquatic macrophytes, aquatic macroinvertebrates, fish and wading-birds. The results show that man-made, excavated secondary channels function as a biotope for riverine species including the more demanding rheophilic species. The demands for shipping and protection against flooding on the River Waal cause constraints on secondary channels. Despite these constraints there is still enough space for hydromorphological processes to create new habitats in secondary channel 1, near Opijnen. The space for hydromorphological processes is less in secondary channel 2, near Beneden-Leeuwen. The density and the number of (rheophilic) species are for a large part influenced by the water level and frequent inundation caused by the high hydrological connectivity. Man-made secondary channels seem to provide suitable habitat that is currently lacking for a broad range of rheophilic macroinvertebrate and fish species in the Lower River Rhine in The Netherlands. Owing to the lack of suitable habitats for rheophilic macroinvertebrate and fish species before the creation of the secondary channels, the importance of longitudinal and transversal migration could be illustrated by the drift of macroinvertebrates during floods and the seasonal migration of Age-0 and Age-1 fish species.
|Impact of sediment pollution on the carrying capacity of benthic communities in river floodplain systems
Lange, H.J. de; Jonge, J. de; Besten, P.J. den; Peeters, E.T.H.M. ; Oosterbaan, J. - \ 2001
In: NCR-days 2001 : from sediment transport, morphology and ecology to river basin management / Stouthamer, E., van Os, A.G., - p. 30 - 31.
sediment - verontreinigende stoffen - benthos - waterverontreiniging - productiviteit - stroomvlakten - waterbodems - noord-brabant - pollutants - water pollution - productivity - floodplains - water bottoms
The main focus of the present research project is to determine and quantify the effect of sediment-bound contaminants on the productivity of benthic macroinvertebrates. The central hypothesis in this study is that sediment pollution leads to a shift in species composition accompanied by a lower productivity of the benthic community, resulting in a decrease of the carrying capacity for fish and waterfowl
Migration of bream between the main channel and floodplain lakes along the lower River Rhine during the connection phase
Grift, R.E. ; Buijse, A.D. ; Klein Breteler, J.G.P. ; Densen, W.L.T. van; Machiels, M.A.M. ; Backx, J.J.G.M. - \ 2001
Journal of Fish Biology 59 (2001). - ISSN 0022-1112 - p. 1033 - 1055.
cyprinidae - migratie - rivieren - meren - stroomvlakten - inundatie - levenscyclus - populatiedynamica - herstel - nederland - rijn - cyprinidae - migration - rivers - lakes - floodplains - flooding - life cycle - population dynamics - rehabilitation - netherlands - river rhine
Mature bream (>30 cm LF) dominated the fish communities in floodplain lakes along the lower River Rhine in The Netherlands, in terms of biomass, in all lakes at all times. In some lakes bream made up 99 f the total fish biomass. While immature, medium-sized bream (10–30 cm) and white bream and roach were abundant in the main channel of the river, these species were almost absent from the floodplain lakes. Inundation of the floodplains did not lead to spatial homogenization of species and length distributions. Small bream (<10 cm) left the floodplains to become resident in the main channel until maturity. Once mature (c. 30 cm), they returned to the lakes during the next inundation and stayed there. Mature bream that moved into the lakes were significantly smaller and had a lower condition than the resident bream. Turbid clay-pits were probably important sources of bream for the lower Rhine and the recruitment of the 0 year group of bream to the riverine population was influenced by their discharge pattern.
Multi-criteria decision support for the revitalisation of river floodplains
Zsuffa, I.J. - \ 2001
Wageningen University. Promotor(en): J.J. Bogardi; J. Leentvaar. - S.l. : S.n. - ISBN 9789058083340 - 155
rivieren - stroomvlakten - natuurbescherming - besluitvorming - overstromingen - ecologie - verbetering - natuurtechniek - donau - floodplains - rivers - floods - nature conservation - ecology - improvement - decision making - ecological engineering - river danube
Ecological revitalisation of river floodplains has become a very actual issue worldwide. It has been recognised that floodplains have the potential to become ecologically very productive areas inhabited by many valuable and rare species. Floodplains also play an important role in regional and even in continental context. Namely, beyond their own ecological values floodplains are also important as far as migration and spreading of species are concerned.
Only very few natural floodplains have been left along the major regulated rivers of Europe. Thus, revitalisation of the existing ones has a special importance. Some of the revitalisation objectives can be achieved by means of administrative measures but there are several problems, which need active engineering intervention. These problems to be remedied are the results of adverse changes in hydrological conditions, which are the most influencing abiotic factors for floodplain ecosystems. The general problem of desiccation for example has been caused by the decreasing water levels in the rivers, following widespread river training since the 19 thcentury.
Thus, the key to ecological revitalisation of river floodplains is improving the water regime. This is proposed to be implemented by transfonning the water conveyance infrastructure in an appropriate manner. Measures like enlarging and/or narrowing floodplain-channels, erecting summer dikes, installing and operating sluices are envisaged for this purpose. Because of the requirements of flood control, navigation and land uses, and also because of conflicts between the envisaged ecological objectives, floodplain revitalisation is inevitably a decision problem with conflicting multiple objectives and multiple stakeholders forming a Decision Making Group (DMG). The task of the DMG is to identify a compromise solution, with satisfactory achievements of all objectives.
This dissertation has been conceived as to develop a computer based Decision Support System (DSS) that assists the DMG in searching for compromise solutions for the ecological revitalisation of river floodplains. The search takes place in a discrete decision space where the alternative solutions are specific combinations of water control measures mentioned above.
The proposed DSS is based on the Evolutionary SEquential Multi-Objective Problem Solving (ESEMOPS) method developed by Bogardi & Sutanto . ESEMOPS actually solves a series of surrogate optimisation problems. These surrogate problems seek a minimum of the deviations between the actual aspiration levels of the DMG regarding the individual objectives and their respective achievements through optimisation. It is important to emphasise that surrogate optimisation problems are not substitutes for an explicit expression of the DMG's preference function. By comparing and analysing the solutions of these problems the DMG only gains information concerning the set of feasible solutions, and learns about the interrelationships (trade-offs) between the applied evaluation criteria. These interrelationships are estimated by alternatively treating some objectives as constraints thus enforcing their achievement. On the basis of intermediate results, the DMG modifies its preference structure (by modifying the aspiration levels) and repeats the surrogate optimisation processes. This iterative-interactive search goes on until the DMG declares a certain solution as the best compromise solution for the given problem.
Surrogate optimisation problems are solved with the help of a Genetic Algorithms (GA) based search technique. The major advantage of GA is that it relies exclusively on information already available in the input (population of alternative solutions), and output (surrogate objective values) of criteria evaluations throughout the search towards the optimum of the actual surrogate problem.
During each GA run a high number of alternative solutions has to be evaluated according to the selected criteria. Criteria evaluation is carried out with the help of a complex modelling system. The most important module of this system is a hydrodynamic model, which enables to simulate the water regime on the floodplain. The applied model is called FOK, which has been developed by the author. FOK belongs to the family of unsteady cell-type floodplain models. Its most pronounced feature is the extremely high simulation speed, which is required by the DSS in order to complete the GA searches within reasonable time limits. The high calculation speed has been achieved with the help of adaptive time step and model configuration control and with that of applying pre-calculated 'delivery functions' for flow calculations in the floodplain-channels. FOK is also enabled to cope with supercritical flow conditions, which may frequently occur in such channels.
Output of the F0K model (water level time series on the floodplain) are input for ecological models. which help to estimate the achievements of ecological criteria. Ecological models embedded into the DSS are ranging from the physiologically based MEGAPLANT model [Scheffer et al., 1993] simulating the growth of water plants to habitat evaluation models for fish and for waders. These habitat models have been formulated by, adopting existing habitat modelling approaches to the unsteady hydrological conditions of floodplains.
The DSS has been tested on a case study problem. The selected area is a sub-system of the Danube riparian Gemenc floodplain in Hungary. The identified ecological objectives prescribe the improvement of conditions for typical alluvial wet ecosystems. Special attention is paid on improving habitat conditions for fish and for waders like the famous black stork (Ciconia nigra) . The set of criteria formulated for the ecological objectives have been supplemented with criteria representing cost minimisation and timber production. This latter is an important economical use of the area, which has to be taken into consideration in the future as well, After identifying the decision and criteria spaces a decision making 'game' has been played with the help of the ESEMOPS based DSS, The purpose of the game was to locate a best compromise solution according to the foreseen preferences of a potential DMG dealing with the revitalisation of the Gemenc floodplain.
It can thus be concluded that developing such a DSS is quite an interdisciplinary task involving the disciplines of ecology, fluid mechanics, numerical modelling, statistics and operations research. Accordingly, the key contribution of the present dissertation is the new, interdisciplinary concept that forms the basis of the proposed DSS. The major challenges that had to be faced during the development of the DSS were selection, adaptation and integration of techniques from the different disciplines.
Fluvial incision and channel downcutting as a response to Late-glacial and Early Holocene climate change: the lower reach of the river Meuse (Maas), The Netherlands
Tebbens, L.A. ; Veldkamp, A. ; Westerhoff, W. ; Kroonenberg, S.B. - \ 1999
Journal of Quaternary Science 14 (1999)1. - ISSN 0267-8179 - p. 59 - 75.
klimaatverandering - rivieren - stroomvlakten - holoceen - maas - climatic change - rivers - floodplains - holocene - river meuse
Historisch - geomorfologische ontwikkeling van enkele riviertrajecten langs de IJssel
Maas, G.J. - \ 1998
Wageningen : DLO-Staring Centrum (Rapport / DLO-Staring Centrum 620) - 35
stroomvlakten - geschiedenis - geomorfologie - kaarten - nederland - ijssel - overijssel - floodplains - history - geomorphology - maps - netherlands - river ijssel - overijssel
Historische kaarten zijn gebruikt om de ontwikkeling van de uiterwaarden van de IJssel tussen Zwolle en Kampen (Beneden-IJssel) en nabij Olst (Sallandse IJssel) te beschrijven. Kenmerkend voor de ontwikkeling van de Beneden-IJssel vanaf 1652 is de vorming van grote, stabiele opwassen (eilanden) in een brede en sterk meanderende laagwaterbedding. Het Zalkerbos heeft een stimulerende werking gehad voor de vorming van kronkelwaardruggen in de Zalkerwaard. In de zwak meanderende Sallandse IJssel is de morfologie van de uiterwaarden het resultaat van de vorming van kleine eilanden in een lokaal verbrede rechte bedding en van kronkelwaardbanken langs binnenbochten. Vanaf 1712 beperken in dit traject de processen zich tot de oeverzone. Door verschillen in de morfologie van de strangen en door een stabielere, hoge waterstand ten opzichte van maaiveld zijn de kansen voor moerasontwikkeling in de Beneden-IJssel groter dan in de Sallandse IJssel.
|Integrale bodemdalingstudie Waddenzee
Beukema, J.J. ; Brinkman, A.G. ; Buijsman, M. ; Dankers, N.M.J.A. ; Dijkema, K.S. ; Dobben, H.F. van; Duin, W.E. van; Ens, B.J. ; Eysink, W.D. ; Fokkink, R.J. ; Gussinklo, H.J. ; Kers, A.S. ; Kruse, G.A.M. ; Marquenie, J.M. ; Onassis, J. ; Oost, A.P. ; Smit, C.J. ; Stive, M.J.F. ; Verboom, B.M.J. ; Verburgh, J.J. ; Vlas, J. de; Walrecht, G. ; Wang, Z.B. ; Wijnen, H.J. van; Zegers, J. - \ 1998
Assen : NAM - ISBN 9789080479159
overstromingsgebieden - bodemdaling - milieufactoren - extractie - mijnbouw - aardgas - bodemkunde - hydrologie - ecologie - habitats - nederland - noordzee - stroomvlakten - overstroomde gronden - waddenzee - bottomlands - subsidence - environmental factors - extraction - mining - natural gas - soil science - hydrology - ecology - netherlands - north sea - floodplains - flooded land - wadden sea
|Nature rehabilitation for the River Rhine: a scenario approach at different scales
Harms, W.B. ; Wolfert, H.P. - \ 1998
In: New concepts for sustainable management of river basins / Nienhuis, P.H., Leuven, R.S.E.W., Ragas, A.M.J., - p. 95 - 113.
rivieren - beheer van waterbekkens - ecologie - stroomvlakten - natuurbescherming - nederland - herstel - natuurtechniek - rijn - rivers - watershed management - ecology - floodplains - nature conservation - netherlands - rehabilitation - ecological engineering - river rhine
De bodemgesteldheid van en kleivoorkomens in de uitbreiding van het landinrichtingsgebied Land van Maas en Waal : resultaten van een bodemgeografisch onderzoek
Scholten, A. ; Brouwer, F. - \ 1997
Wageningen : DLO-Staring Centrum (Rapport / DLO-Staring Centrum 589, 157) - 49
zware kleigronden - stroomvlakten - bodemkarteringen - keramiek - klei - industrie - nederland - dijken - kaarten - land van maas en waal - clay soils - floodplains - soil surveys - maps - ceramics - clay - industry - netherlands - dykes - land van maas en waal
Physiography and formation of the holocene floodplain along the lower course of the Rhine in The Netherlands
Havinga, A.J. ; Hof, A.J. op 't - \ 1983
Wageningen : Agricultural University (Mededelingen / Landbouwhogeschool 83-8) - ISBN 9789067540520 - 73
bodemkarteringen - kaarten - geologie - rivieren - sediment - nederland - stroomvlakten - betuwe - gelderland - soil surveys - maps - floodplains - geology - rivers - sediment - netherlands - betuwe - gelderland
Rapport betreffende de inventarisatie van de uiterwaardgronden langs de Rijn en de Waal, ten behoeve van de steenindustrie
Buringh, P. - \ 1953
Wageningen : STIBOKA (Rapport / Stichting voor Bodemkartering no. 282) - 72
klei - extractie - veldspaat - kaarten - mijnbouw - polders - bodemkarteringen - wetlands - Nederland - stroomvlakten - gelderland - uiterwaarden - clay - extraction - felspar - maps - mining - polders - soil surveys - wetlands - Netherlands - floodplains - gelderland - river forelands
Bodemgeschiktheid uiterwaarden voor kleiwinning