Staff Publications

Staff Publications

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

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

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

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

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Bringing in the floods : a comparative study on controlled flooding in the Dutch, Bangladesh and Vietnamese deltas
Staveren, Martijn F. van - \ 2017
University. Promotor(en): Jan van Tatenhove, co-promotor(en): Jeroen Warner; Flip Wester. - Wageningen : Wageningen University - ISBN 9789463437035 - 174
water management - flooding - deltas - hydraulic engineering - rivers - environmental management - environmental policy - environmental control - netherlands - vietnam - bangladesh - waterbeheer - inundatie - delta's - waterbouwkunde - rivieren - milieubeheer - milieubeleid - milieubeheersing - nederland

This thesis investigates contested initiatives to restore controlled flooding in the deltas of the Dutch, Bangladesh and Vietnamese (Mekong) deltas. Restoring controlled flooding is a seemingly contradictory measure in densely populated delta areas, where approaches based on full flood prevention has been typically dominant for decades. This has instigated the question how the emergence of restored controlled flooding initiatives can be explained. Related, this study reflects on how controlled flooding could contribute to long-term flood risk management and sustainable development in deltas, which are simultaneously attractive and vulnerable places for humans to live in. In order to answer this question, a case study approach has been used to investigate social, environmental and technological factors that have shaped controlled flooding initiatives. Cases have been identified that materialized under different conditions: from very dynamic delta environments to relatively stable ones, and from interventions driven by “top-down” policies to “bottom-up” action to modify or remove embankments. This thesis has an article-based structure, which means that individual chapters (2-5) have been designed for publication with peer reviewed academic journals. Chapter 1 provides the general background information, problem definition, and objectives. Chapter 6 ties together the findings of the individual case study chapters and presents the conclusions.

Chapter 2 conceptualizes deltas as interacting social-ecological-technological systems. It argues that a better understanding of how hydraulic infrastructure influences social processes and environmental dynamics in deltas is critical to understand how deltas evolve over time. By means of the delta trajectories concept, the chapter presents a way to understand this interaction. It also presents a way to understand the sustainability of a delta trajectory, and discusses how new flood management concepts might contribute to “realigning” the development trajectory towards more sustainable system states.

In Chapter 3, the first controlled flooding case is investigated. The Noordwaard is an agricultural polder, located at the junction of tides and riverine discharge in the Netherlands. As part of the Room for the River programme, the northern embankments were lowered which enables the inflow of water during high water levels in the river Merwede. This reduces peak water levels in the river, supports the adjacent freshwater Biesbosch wetland by means of restored water dynamics, but also affects the possibilities for agricultural production. The chapter highlights that a strong coupling can be observed between the domains of water safety and nature development objectives, and that a top-down decision concluded a long stakeholder negotiation processes. From the perspective of “subsiding polder lands,” controlled flooding is not regarded for its strategic importance, as excessive sedimentation would hamper the intended design discharge of the area.

Chapter 4 explores the Tidal River Management concept. In the coastal zone of Bangladesh, community-enforced embankment breaches have opened up some of the polders or low-lying areas called “beels,” and exposed them to tidal influence again. Besides stimulating agricultural production and providing safer places to live in, the extensive network of polder embankments also caused increased sedimentation in the region’s rivers, and water logging in enclosed areas due to insufficient drainage possibilities. The chapter highlights that policy debates in Bangladesh have revolved around adopting “open” or “closed” approaches, where TRM represents a hybrid form. The case showed that TRM involves water management and sediment management, and that it represented a “social opening up” for local communities and NGOs to get involved with water projects and embankment removal.

Plans to restore seasonal flooding in the Mekong delta are center stage in Chapter 5. The Mekong delta system is very dynamic and dealing with the delta’s water resources, in connection with intensive rice production, have been heavily debated by Vietnamese and international policy makers. This chapter investigates a number of older and more recent long-term development plans for the Mekong delta. This analysis highlights how ideas about controlled flooding and flood control have gradually evolved over time. The most recent delta management plan suggests to restore seasonal flooding in some parts of the delta, as a way to safeguard downstream urban areas from peak flows, and as a way to improve the conditions for agricultural production.

Chapter 6 summarizes the findings of the case study chapters one by one, and concisely answers the research questions. It highlights key similarities and differences when it comes to social, environmental and technological dimensions, and discusses these findings with the literature on flood risk management policy, complex adaptive systems research, and delta studies. The findings demonstrate that environmental dynamics have been critical to emphasize the potential of restoring controlled flooding, but that social and technological factors have been important enablers or constrainers for controlled flooding initiatives to take shape. In itself, controlled flooding reconciles ecosystem-based ideas about flood management with more mainstream policies based on flood control. For this reason controlled flooding can be seen as a “niche-development” with limited influence on how flood management policies, and environmental delta systems, evolve. At the same time, controlled flooding has been acknowledged for its strategic opportunities, for example when it comes to diverting peak water discharges, land heightening by means of capturing suspended sediment, and by providing nutrient for agricultural. This offers opportunities for further thinking about and conceptual development of controlled flooding.

Quantifying the impact of socioeconomic development and climate change on Escherichia coli concentrations in the Pakistani Kabul River
Iqbal, Shahid - \ 2017
University. Promotor(en): Rik Leemans, co-promotor(en): Nynke Hofstra. - Wageningen : Wageningen University - ISBN 9789463434478 - 183
escherichia coli - rivers - climatic change - socioeconomics - water quality - regression analysis - water pollution - health - rivieren - klimaatverandering - sociale economie - waterkwaliteit - regressieanalyse - waterverontreiniging - gezondheid

Clean water is indispensable for the sustenance of life and maintenance of health. However, water quality is threatened by changes in socio-economic developments (population growth, urbanisation, livestock increase and sanitation) and climate (surface air temperature and precipitation patterns). Major water quality contaminants include microorganisms, such as fecal coliforms, Escherichia Coli (E.coli) and pathogens. Microbial contamination poses serious health risks in developing countries like Pakistan, where people do not have access to clean water due to lack of waste water treatment and thorough manure management. Therefore, to reduce the present and future health risk, it is important to understand the impacts of socio-economic development and climate-change on microbial fate and transport in surface water resources in the Kabul River Basin in Pakistan.

The objective of this study is quantifying the impact of socio-economic development and climate change on E.coli concentrations in the Pakistani Kabul River. To reach the objective, I sampled E.coli concentrations at several locations in Kabul River, applied statistical and process based modelling, developed future global change scenarios and analysed the impact of these scenarios on E.coli concentrations. I focus on E.coli rather than pathogens, because sampling of pathogens and its chemical analysis are expensive. Kabul River Basin is a tributary of the Indus river and is located in the Hindukush-Karakoram-Himalayas (HKH) and suffers from floods every year. The population suffers from a high risk of waterborne diseases. The water is contaminated by direct sewage inputs from large cities, like Peshawar, direct manure inputs from animal sheds along the river and indirect manure inputs from the land.

Kabul River Basin is subjected to hazardous levels of microbiological pollution. The concentration of micro-organisms is influenced by hydro-climatic variables, such as water and surface air temperature, precipitation and discharge. However, the net effect of these variables remains thus far unclear. High concentrations of E.coli were found in the main stream and its tributaries (Chapter 2). Samples were collected along the Kabul river and drinking water samples from the city of Nowshera (April 2013 to July 2015) and all surface water samples violate the bathing water criteria and all drinking water samples violate the drinking water criteria. The correlation between hydro-climatic variables and E.coli concentration was analysed. Water temperature and surface air temperature were positively correlated, most likely because high temperatures coincide with high precipitation and discharge. Precipitation and river discharge data were also positively correlated with E.coli concentrations. This shows that precipitation, which increases the surface runoff, transports E.coli and other waterborne pathogens to the river nearby (correlation with precipitation) and further upstream (correlation with discharge). A regression model was also applied that explained 61% of the E.coli variability in surface water and 55% of E.coli variability in drinking water resources, even when other factors, such as location and land-use variables are ignored (Chapter 2).

To better understand the hydrology in the basin, the current and future flows of Kabul river were modelled using the Soil and Water Assessment Tool (SWAT), which serves as a basis for the process-based E.coli model. Flash floods occur every year in the basin as a result of increased discharge due to snow and glacier melt together with monsoon precipitation. The Kabul River Basin is one of the most vulnerable regional basin to climate change. The hydrological model was calibrated and validated for the full Kabul River Basin and performed well (NSE equals 0.77 and 0.72 respectively). Flood frequency and expected return period were analysed for a contemporary period (1981-2000) and two future periods (i.e. 2031-2050 and 2081-2100) using the Representative Concentration Pathway (RCP) 4.5 and RCP8.5 scenarios based on four bias-corrected downscaled climate models (Chapter 3). The flood frequency analysis shows that the present day’s one-in-a-fifty year event could occur between once in every 3 year (EC-EARTH and MIROC climate-models) and once in every 24 years (IPSL climate-model). This study presents climate-change impact assessment in the Kabul River Basin. The selected approach is in general well accepted in the scientific community and the results can be useful in flood management in the region. Outcomes of this study can be helpful for regions that have similar hydro-climatological conditions.

To better understand the fate and transport of bacteria from land to water resources and to assess source contribution, the SWAT model was calibrated and validated for E.coli. Our study is the first bacterial modelling study for the Kabul River Basin (Chapter 4). The simulated concentrations have slightly lower variability than the observed concentrations. The model performance could be improved further by using more input E.coli data, but the current model results agree well enough with our measured E.coli concentrations (NSE equals 0.69 and 0.66 for calibration and validation respectively). Based on the pathogen source estimations, point (direct) sources are identified to be the most important microbial pollution sources. Pollution from upstream areas is also important, while non-point (diffuse) sources play a role mostly during the periods with high discharge. Our study underlines the importance of wastewater treatment and manure management both in and upstream of the study area. Studies like ours were lacking in developing countries like Pakistan and can be used for scenario analyses in the region (Chapter 4). The model can be useful in microbial water quality assessments in other watersheds and for pathogenic microorganisms, such as Cryptosporidium and Rotavirus.

The calibrated and validated SWAT bacterial model (Chapter 4) was used to assess E.coli concentrations in a comprehensive scenario analysis (Chapter 5). We developed two future scenarios based on state-of-the-art approaches, using the Shared Socio-economic Pathways (SSPs), RCPs and own assumptions in line with the SSP storylines. We took the modelled E.coli concentrations from Chapter 4 as baseline scenarios and defines two future scenarios as Scenario_1 (sustainability scenario) and Scenario_2 (uncontrolled scenario). These scenarios represent different socio-economic development and climate change. The two scenarios were developed by combining SSP1, a sustainable, equitable and environmentally focussed world with RCP4.5 (limed climate change) in Scenario_1, and SSP3 (a divided world, with no interest in the environment) with RCP8.5 (strong climate change) in Scenario_2. Currently, no wastewater treatment plant exists in the basin, because the 2010 floods destroyed the available plants. We assumed excellent and poor wastewater and manure treatment for 2050s and 2100s for Scenario_1 and Scenario_2 respectively, in line with the storylines. Scenario_2 resulted in higher E.coli concentrations compared to the baseline scenarios due to high population growth, poor wastewater and manure treatment and land-use changes. However, microbial water quality was found to improve under Scenario_1. This was achieved by implementing improved and technologically advanced wastewater treatment and manure management. Future concentrations were found to be between 0.6% and 7% of the baseline concentrations depending on the treatment technology used (Chapter 5). This study highlights the need for substantial improvements in wastewater and manure treatment systems in the Kabul River Basin to assure future E.coli concentrations in water sources will be within the limits of WHO and US-EPA regulations for drinking and bathing water quality. The primary treatment facility that is currently installed is a good start, but insufficient to strongly reduce concentrations. Hence major investments are required to install technologically advanced wastewater treatment and manure treatment plants to cut-down the current contamination level of Kabul river.

My PhD thesis provides a base for devising optimal coping strategies that are essential for the sustainability of hydrological resources under socio-economic developments and climate-change impacts. The results of our research are helpful to further assess alternative water quality management options. The outcomes of this study also increase the knowledge in the field of microbial fate and transport in water resources in a developing country like Pakistan, where such studies are lacking. A limited number of previous studies on global change impacts on microbial contamination of surface water in other areas of the world focused only on the climate-change impacts on microbial water quality. This is the first study to evaluate the influence of combined socio-economic and climate-change impacts on E.coli concentrations in the Kabul River Basin. The developed SWAT model and scenario analysis can be used for other contaminants, such as nutrients, pesticides and heavy metals. Our study can be a first step to improve water quality of the Kabul River Basin by providing tools for water managers and health specialists to improve the water quality and reduce the risks related to the use of contaminated water resources. This study will be useful not only in this region, but also for other regions of the world with similar microbial water contamination issues.

Assessing the impact of socio-economic development and climate change on faecal indicator bacteria in the Betna River, Bangladesh
Islam, Majedul - \ 2017
University. Promotor(en): Rik Leemans, co-promotor(en): Nynke Hofstra. - Wageningen : Wageningen University - ISBN 9789463436304 - 137
climatic change - environmental impact - water quality - rivers - contamination - bacteria - coliform bacteria - faecal coliforms - bangladesh - south asia - klimaatverandering - milieueffect - waterkwaliteit - rivieren - besmetting - bacteriën - coliformbacteriën - fecale coliformen - zuid-azië

Consumption of water that is contaminated with pathogens still causes high numbers of death and disease. Understanding the factors that influence the dynamic distribution of waterborne pathogens is important, as this will help understanding improvements and possible solutions. Such understanding is particularly important in a developing country like Bangladesh, where large proportions of the population often have little or no access to clean water. Despite the high relevance for public health, few studies currently exists on the fate and transport of pathogens and the so-called Faecal Indicator Bacteria (FIB, e.g. E. coli, enterococci) in (sub)tropical systems. FIB are susceptible to shifts in water flow and quality. The predicted increases in rainfall and floods due to climate change will exacerbate the faecal contamination scenarios. This could be further compounded by the rapid change in socio-economic conditions (population growth, urbanization, sanitation and agricultural management) in the developing countries. Therefore, to reduce future health risks, understanding the influence of changes in socio-economic conditions and climate on microbial dynamics is important.

Very few studies have quantified the relationship between the waterborne pathogens/FIB concentrations and climate and socio-economic changes. In this study a process-based model was developed and a scenario analysis was performed based on the new combined climate and socio-economic changes scenarios, to assess the present and future river hydrodynamics, FIB sources, die-off processes and concentrations. We used FIB, because measuring FIB are cheaper than pathogens. FIB are usually not pathogenic but their presence indicates the likely presence of waterborne pathogens. These pathogens are expected to respond to climate change in a comparable way to FIB. The present study is based on the Betna River basin in southwestern Bangladesh, where faecal contamination is not monitored and very little knowledge exists on the distribution of contaminants.

First of all, FIB concentrations of the river water were measured to identify the river’s faecal contamination levels that can be used to validate the water-quality model. In the study area, wastewater is not treated and this untreated wastewater is discharged directly into the river. This is evident from the measured FIB data. In 88% of the E. coli and all enterococci samples, the USEPA bathing water quality standards were violated (Chapter 2). Such violation indicates potential health risks associated with the use of the river water for domestic, bathing and irrigation purposes. The correlation between environmental variables (water temperature, precipitation and salinity) and FIB concentrations was also determined. A positive correlation was found with water temperature and precipitation, and a negative correlation with salinity. The positive correlation with temperature is due to the co-occurrence of high summer temperature with abundant monsoon rainfall. The positive correlation with precipitation can be explained by the increased runoff from agricultural lands and urban areas. This runoff contains many bacteria. In the study area, during the rainy season (July to September) precipitation increases and as a result water salinity decreases. The observed negative correlation with salinity is more likely due to the typical weather patterns during the rainy season when low salinity coincides with increased precipitation and high temperature, than to salinity dependent die-off of bacteria. A regression model was applied that explained almost half of E. coli and enterococci variability in river water. This, however, only considers water temperature and precipitation (Chapter 2).

Then, the present and future hydrodynamics of the river were simulated using a two dimensional hydrodynamic model (MIKE 21 FM). Although the main goal of this thesis is to assess the river’s present and future FIB concentrations, the reasons for this hydrodynamic modelling are twofold. Firstly, outputs of the hydrodynamic model are used as input into the water-quality model (Chapter 4). Secondly, hydrodynamics (i.e. water level and discharge) are simulated because increased water level and discharge together with sea level rise stimulate floods in the river basin. These floods are related to outbreaks of waterborne diseases. The modelled results corresponded very well with the measured water levels and discharges. The model was applied to simulate baseline and future water levels and discharge for Representative Concentration Pathway RCP4.5 and RCP8.5 scenarios using bias-corrected downscaled data from two climate models (IPSL-CM5A and MPI-ESM). The model results showed an expected increase in water level up to 16% by the 2040s and 23% by the 2090s (Chapter 3). The monsoon daily maximum discharge was expected to increase up to 13% by the 2040s and 21% by the 2090s. These model results also showed that the duration of the water level above the danger level and extreme discharge periods can increase by half a month by the 2040s and over a month by the 2090s. The coincidence of the water danger level with extreme discharge may cause disastrous floods in the study area.

Next, the hydrodynamic model was coupled with a water-quality module (ECOLab). The fate and transport of FIB was simulated, the influence of different processes tested and the contribution from different sources to the total contamination quantified (Chapter 4). The model outputs corresponded very well with the measured FIB data. The present river microbial water quality based on measured and simulated results indicated, once again, noncompliance with bathing water standards. Primary and secondary levels of wastewater treatment were not sufficient to reach the standards most of the time, and discharges from sewer drains and incoming concentrations from the upstream boundary were found to be a major cause of water contamination. Tide, wind and diffuse sources (urban and agricultural runoff) contributed little. The high FIB inputs from the upstream open boundary come from untreated point source discharges from upstream urban areas and accumulation of diffuse contaminants from the large upstream areas. Therefore, this study underlines the need for establishment of wastewater treatment plants both in the studied basin and upstream urban areas. This study provides insight into bacterial fate and transport mechanisms, contribution of different sources to the faecal contamination and applicability of wastewater treatment in a river of a subtropical developing country where this type of study is lacking. Uncertainties are related to the lack of high temporal resolution measured FIB data and the lack of available data for contaminant loads from septic tank leakages, open defecation and sediment resuspension. However, the model well captured the measured FIB variability, suggesting that it can be applied for microbial water quality assessments in other watersheds of the world with similar characteristics.

The developed model could be an ideal tool to forecast future impacts of climate and socioeconomic changes on FIB fate, transport and dynamics. Finally, future FIB concentrations were simulated using the coupled hydrodynamic and microbial model (MIKE 21 FM-ECOLab) and scenario analysis (Chapter 5). Scenarios have been developed building on the most recent Shared Socio-economic Pathways (SSPs) and Representative Concentration Pathways (RCPs) scenarios from the Intergovernmental Panel on Climate Change (IPCC). We developed a baseline scenario (October 2014–September 2015) reflecting the current conditions and two future scenarios, S1 (sustainability scenario) and S2 (uncontrolled scenario) mimicking different future developments of socio-economic (population, urbanization, sanitation, wastewater treatment development, land use) and climate-change factors (temperature, precipitation and sea-level rise). In S1 RCP4.5 was combined with socio-economic scenarios SSP1, and for S2 RCP8.5 was combined with SSP3 (S2). Assumptions on sanitation, waste water treatment and agricultural management in line with the storylines were made to quantify future changes in FIB concentrations and consequent health risk. Different future scenarios were found to have substantial impact on FIB concentrations in the river. By the 2090s, FIB concentrations are expected to decrease by 98% or increase by 75% for the sustainability scenario and uncontrolled scenario respectively. An uncontrolled future resulted in a deterioration of microbial water quality due to socio-economic developments, such as higher population growth, land-use change and increased sewage discharges and changes in rainfall patterns. Microbial water quality strongly improved under a sustainable climate and improved sewage treatment. FIB concentrations were much more sensitive to changes in socio-economic factors than to changes in climatic factors. This underlines the importance of socio-economic factors in assessing and improving microbial water quality.

The results show the importance of improvements in sanitation and wastewater treatment in the Bangladeshi Betna River basin to ensure that future FIB concentrations in the river comply with the US-EPA bathing water quality standards. Major investments to construct wastewater treatment plants are necessary to compensate for the population growth and increased the volume of wastewater treatment. Although the current level of contamination is already too high, without wastewater treatment the water quality will further deteriorate.

The thesis assesses the present and future FIB dynamics in the Betna River through sampling, statistical and process-based modelling, and scenario analysis. The results contribute to increase the knowledge base on the dynamic distributions of the FIB in surface water in a developing country and in a subtropical system, where this type of study is lacking. It also reduces the knowledge gaps regarding future flooding scenarios at the local scale. While some earlier studies focused on only assessing climate-change impacts on microbial water quality, this study for the first time assessed the influence of combined climate and socio-economic scenarios (using scenarios based on the new SSP-RCP scenario matrix) on river FIB concentrations. This combined modelling and scenario approach enables the assessment of faecal contamination sources and dynamics at present and in the future. The developed model and scenario analysis approach provides a basis for the water managers to reduce the widespread faecal contamination and the risks of waterborne disease outbreaks, which are still a leading cause of deaths in developing countries.

Role of reservoir operation in sustainable water supply to Subak irrigation schemes in Yeh Ho River Basin
Yekit, Mawiti Infantri - \ 2017
University. Promotor(en): E. Schultz, co-promotor(en): I. Nyoman Norken; László Hayde. - Leiden : CRC Press/Balkema - ISBN 9781138065437 - 250
irrigation systems - irrigation - water supply - sustainability - basin irrigation - indonesia - rivers - irrigatiesystemen - irrigatie - watervoorziening - duurzaamheid (sustainability) - kombevloeiing - indonesië - rivieren

A Subak irrigation scheme, primarily in Bali, Indonesia concerns an irrigation system of which the construction, operation and management are based on agreed principles of technology, management of agriculture and religious community. Subak systems have been well known since the 9th Century. As a manifestation of the Cultural Landscape of Bali Province the Subak schemes are since June, 2012 included in the World Heritage List of UNESCO. These systems are managed by a Subak Association based on the Tri Hita Karana philosophy - harmony between human beings and God, harmony between people and nature, and harmony between people and people.

The problem of insufficient water in the dry season developed in the Yeh Ho River Basin. Because of this the main objective of this study was to develop an optimal reservoir operation strategy in relation to the water supply of the Subak irrigation schemes, capable to support agricultural productivity at upstream, midstream and downstream level. Based on a Generic Algorithm the RIBASIM model was applied using the dependable 80% of discharge and shifting the start of land preparation. The results provide evidence that the cropping pattern of the fifth scenario results in an overall optimal agriculture production of the Subak schemes. The recoverable flow considered in the river basin scheme model plays an important role in the optimisation. Nevertheless, if a normal hydro-climate occurs, the other scenarios, especially the first scenario, can be applied as well. This reflects the applicability of the Tri Hita Karana philosophy on harmony among people and harmony among people and nature.

From harmful to useful algae
Blaas, Harry - \ 2017
University. Promotor(en): Carolien Kroeze. - Wageningen : Wageningen University - ISBN 9789463430357 - 117
algae - algae culture - adverse effects - nitrogen - phosphorus - rivers - eutrophication - waste water treatment - europe - algen - algenteelt - nadelige gevolgen - stikstof - fosfor - rivieren - eutrofiëring - afvalwaterbehandeling - europa

Eutrophication of coastal waters is a worldwide phenomenon. This study focuses on eutrophication in the coastal waters of Europe. Eutrophication is mainly a result of the increased transport of nutrients from watersheds by rivers to the coastal waters. Nutrient losses from watersheds are generally from agriculture, sewage, atmospheric deposition and from natural sources. In case of an overload of nutrients in the coastal waters, algal blooms may develop which increase the risk of hypoxia, fish mortality, and loss of biodiversity.

Algae can also be useful. They are increasingly considered an interesting product. For instance, micro-algae can be grow on land to produce proteins, lipids and fatty acids. Some studies indicate that micro-algae can be an important feedstock in the future for, for instance, the production of biodiesel. Moreover, macro-algae can be produced in seawater in sea farms. Macro-algae can be edible, or be used as a feedstock. By yielding macro-algae, nutrients are removed from the water, reducing coastal eutrophication.

The objective of this study is to analyse past and future trends in nutrient export by rivers to European seas with a focus on the role of algae. Three types of algae will be distinguished: (1) harmful algal blooms in coastal seas, (2) cultivation of micro-algae on land for the production of proteins, lipids and fatty acids, and (3) cultivation of multi cellular algae in seaweed farms for human consumption or other products.

To meet the objective the following research questions are addressed:

RQ1 To what extent do N and P loads exceed levels that minimize the risk of harmful algal blooms, and what are the relative shares of sources of N and P in rivers of the European Union?

RQ2 What are the potential consequences of large-scale land-based production of biodiesel from cultivated micro-algae in Europe for coastal eutrophication?

RQ3 Would it possible to cultivate and process micro-algae in a factory, and what is the environmental performance?

RQ4 To what extent can seaweed farming in combination with nutrient management in agriculture and waste water treatment reduce the potential for coastal eutrophication?

These questions are answered through model analyses. The Global NEWS (Nutrient Export from WaterSheds) model simulates river export of nutrients as function of human activities on land. It includes more than 6000 rivers worldwide. It can be used to quantify nutrient flows from land to sea for the years 1970, 2000, 2030 and 2050. For future years four scenarios have been implemented. One of these scenarios is named Global Orchestration and mostly used as a reference in this thesis. This scenario assumes a globalised world, with a reactive approach towards environmental problems. The model was released in 2010, has been validated for the years 1970 and 2000. The nutrients considered in the model are nitrogen (N) and phosphorus (P). In this thesis Global NEWS is used to calculate transport of nutrients to the coastal waters of Europe. The model uses ICEP (Indicator for Coastal Eutrophication Potential) values at the river mouths as an indicator for potentially harmful effects of nutrient enrichment. These ICEP values reflect the ratio of nitrogen and phosphorus to silica in coastal seas. A positive ICEP value indicates that nitrogen or phosphorus levels are too high, favouring conditions for potentially harmful algae to bloom.

In chapter 2 Global NEWS is used to calculate the transport of nutrients and ICEP values for 48 European rivers for the years 2000 and 2050. The model calculates a positive ICEP for 38 rivers in the year 2000, and for 34 rivers in the year 2050. This indicates that current policies are not so effective in reducing the river transport of nutrients. For polluted rivers the anthropogenic sources of the nutrients are investigated. For most rivers the dominant polluting sources are agriculture or sewage. The results indicate that a basin-specific policy is needed to reduce the risks of coastal eutrophication.

In chapter 3 the focus is on useful algae: micro-algae cultivation on land for, for instance, biodiesel production. The consequences of large-scale production of biodiesel on nutrient export by rivers to the European coastal waters are investigated. A scenario is developed assuming that a production of 0.4 billion m3 diesel from cultivated micro-algae. The cultivation is assumed to be in the open air, for instance in ponds or in closed tube systems. Such production levels would need a land surface area as large as Portugal. The Global NEWS model is used to calculate the amount of waste water from micro-algae production that will be transported to the coastal waters in this scenario. The results indicate that large-scale cultivation of micro-algae on land can become a source of nutrient pollution in rivers. In the scenario with large-scale micro-algae cultivation the future transport of nitrogen and phosphorus is considerably higher than in the reference scenario. To ensure sustainable production of biodiesel from micro-algae it is important to develop cultivation systems with low nutrient losses to the environment.

Chapter 4 presents a design of a factory for the cultivation and processing of micro-algae in an environmentally sound way. The factory does not use fossil fuels and applies maximum recycling of water and nutrients. In this factory it is possible to produce lipids, carbohydrates, proteins and minerals. The factory can be built on any piece of land, so there is no need to use arable land. The factory is independent of weather and climate. Energy can be delivered by wind mills. In this chapter an example of producing diesel in the factory is shown. In the 12 stories factory with a cultivation area of 1 hectare, 810 ton micro-algae can be cultivated per year. This is enough for the production of 386 ton diesel per year.

Chapter 5 focuses on mitigation of eutrophication in European coastal waters. A scenario is presented assuming different types of measures. The scenario first assumes that nutrient use efficiencies in agriculture are higher than today, and that waste water treatment in sewage systems is improved. In addition, it assumes that all excess N and P in coastal waters is harvested in seaweed farms producing edible macro-algae. In our scenario for 2050 there is seaweed farming in the coastal waters of 34 rivers mouths in Europe .NEWS The areas needed to ensure that ICEP values remain below 0 (low potential for coastal eutrophication) range between 0 and 952 km2 per river mouth.

This thesis shows that algae can be both harmful and useful. River export of nutrients can lead to coastal eutrophication increasing the risks of harmful algal blooms. On the other hand, micro-algae can be produced without environmental harm on land, and macro-algae can be useful in reducing pollution levels in coastal seas. This thesis could serve as a basis for environmental policies to stimulate the production of these useful algae. The methods to mitigate algal blooms and to use algae in a sustainable way in this thesis are also useful for other parts of the world.

River export of nutrients to the coastal waters of China: the MARINA model to assess sources, effects and solutions
Strokal, Maryna - \ 2016
University. Promotor(en): Carolien Kroeze, co-promotor(en): S. Luan; Lin Ma. - Wageningen : Wageningen University - ISBN 9789462579729 - 226
cum laude - nutrients - rivers - coastal water - models - eutrophication - coastal areas - water pollution - china - voedingsstoffen - rivieren - kustwateren - modellen - eutrofiëring - kustgebieden - waterverontreiniging

Rivers export increasing amounts of nitrogen (N) and phosphorus (P) to the coastal waters of China. This causes eutrophication problems that can damage living organisms when oxygen levels drop and threaten human health through toxic algae. We know that these problems result from human activities on land such as agriculture and urbanization. However, the relative importance of these human activities for river export of nutrients to Chinese seas is not well studied. There are two important issues that need further investigation: the relative importance of upstream pollution on downstream impacts and the relative importance of typical sources of nutrients in Chinese rivers that are often ignored in existing modeling studies.

My PhD thesis, therefore, aims to better understand trends in river export of nutrients to the coastal waters of China by source from sub-basins, and the associated coastal eutrophication. To this end, I developed the MARINA model: Model to Assess River Inputs of Nutrients to seAs. For this, I used the existing Global NEWS-2 model (Nutrient Export from WaterSheds) as a starting point.

I formulated five sub-objectives to achieve the main objective:

To analyze the original Global NEWS-2 model for river export of nutrients and the associated coastal eutrophication (Chapter 2);

To develop a sub-basin scale modeling approach to account for impacts of upstream human activities on downstream water pollution, taking the Pearl River as an example (Chapter 3);

To quantify the relative share of manure point sources to nutrient inputs to rivers at the sub-basin scale (Chapter 4);

To quantify the relative share of sources to river export of nutrients at the sub-basin scale (Chapter 5);

To explore optimistic futures to reduce river export of nutrients and coastal eutrophication in China (Chapter 6).

The study area includes rivers draining roughly 40% of China. This includes the most densely populated areas, and areas with intensive economic activities. The rivers include the Yangtze (Changjiang), Yellow (Huanghe), Pearl, Huai, Hai and Liao. In the MARINA model, the drainage areas of the large Yangtze, Yellow and Pearl rivers are divided into up-, middle- and downstream sub-basins. The principle of the sub-basin approach of MARINA is that nutrients from human activities are transported by tributaries to outlets of sub-basins and then to the river mouth (coastal waters) through the main channel. The model takes into account nutrients that are partly lost or retained during transport towards the river mouth. The model quantifies river export of nutrients by source from sub-basins for 1970, 2000 and 2050.

The main six findings of the MARINA results for China are:

Finding 1: Dissolved N and P export by Chinese rivers increased by a factor of 2-8 between 1970 and 2000;

Finding 2: The potential for coastal eutrophication was low in 1970 and high in 2000 in China;

Finding 3: Most dissolved N and P in Chinese seas is from middlestream and downstream human activities;

Finding 4: Manure point sources are responsible for 20-80% of dissolved N and P in Chinese rivers;

Finding 5: In the future, river export of nutrients may increase in the Global Orchestration (GO) scenario of the Millennium Ecosystem Assessment. Current policy plans (CP scenario) may not sufficient to avoid this increase;

Finding 6: In optimistic scenarios (OPT-1 and OPT-2), the potential for coastal eutrophication is low in 2050, mainly as a result of assumed full implementation of: (1) high recycling rates of animal manure (OPT-1 and OPT-2), and (2) high efficiencies of nutrient removal in sewage systems (OPT-2, see Figure 1).

Figure 1. Illustration of future scenarios for coastal water quality in China. GO is Global Orchestration of the Millennium Ecosystem Assessment and assumes environmental actions that are either absent or ineffective in reducing water pollution. CP is based on GO, but incorporates the “Zero Growth in Synthetic Fertilizers after 2020” policy. OPT-1 and OP-2 are optimistic scenarios that assume high nutrient use efficiencies in agriculture (OPT-1, OPT-2) and sewage (OPT-2).

My PhD thesis reveals novel insights for effective environmental policies in China. It shows the importance of manure point sources in water pollution by nutrients. Clearly, managing this source will likely reduce coastal eutrophication in the future. Furthermore, the implementation of advanced technologies is essential when dealing with urban pollution. My PhD thesis may also be useful for other world regions with similar environmental problems as in China. The new, sub-basin scale MARINA model is rather transparent and thus can be applied to other large, data-poor basins that may benefit from the allocation of effective management options. With this I hope to contribute to future availability of sufficiently clean water for next generations, not only in China, but also in other world regions.

Legitimatie van de nevengeul voor de Waal langs Varik : constructies van risico’s uit onzekerheden die redenen geven voor voorzorg : publieksrapport
During, R. ; Pleijte, M. ; Vreke, J. - \ 2016
Wageningen : Wageningen UR, Wetenschapswinkel (Rapport / Wetenschapswinkel Wageningen UR 324a) - ISBN 9789462578180 - 39 p.
klimaatverandering - rivieren - waal - hoogwaterbeheersing - afvoer - burgers - waterbeheer - rivierregulering - climatic change - rivers - river waal - flood control - discharge - citizens - water management - river regulation
“Wat is de legitimatie van de geprojecteerde nevengeul van de Waal bij Varik en Heesselt?” In het onderzoek dat heeft plaatsgevonden is specifiek gekeken naar de onderbouwing van de maatgevende afvoer van 18.000 m3/s bij Lobith eind 21e eeuw en naar de wijze waarop er in de planvorming met de onzekerheden rondom de maatgevende afvoer is omgegaan. Daarbij is in eerste instantie gekeken naar de onderbouwing die door de provincie en door het stafbureau van de Deltacommissaris is aangeleverd aan de bewoners. In tweede instantie moest er veel ruimer gezocht worden naar onderbouwende publicaties, want die onderbouwing had het karakter van “work in progress”.
Legitimatie van de nevengeul voor de Waal langs Varik : constructies van risico’s uit onzekerheden die redenen geven voor voorzorg : achtergrondrapport
During, R. ; Pleijte, M. ; Vreke, J. - \ 2016
Wageningen : Wageningen UR, Wetenschapswinkel (Rapport / Wetenschapswinkel Wageningen UR 324b) - ISBN 9789462573895 - 141 p.
klimaatverandering - rivieren - waal - hoogwaterbeheersing - afvoer - burgers - waterbeheer - rivierregulering - climatic change - rivers - river waal - flood control - discharge - citizens - water management - river regulation
“Wat is de legitimatie van de geprojecteerde nevengeul van de Waal bij Varik en Heesselt?” In het onderzoek dat heeft plaatsgevonden is specifiek gekeken naar de onderbouwing van de maatgevende afvoer van 18.000 m3/s bij Lobith eind 21e eeuw en naar de wijze waarop er in de planvorming met de onzekerheden rondom de maatgevende afvoer is omgegaan. Daarbij is in eerste instantie gekeken naar de onderbouwing die door de provincie en door het stafbureau van de Deltacommissaris is aangeleverd aan de bewoners. In tweede instantie moest er veel ruimer gezocht worden naar onderbouwende publicaties, want die onderbouwing had het karakter van “work in progress”.
Alarming nutrient pollution of Chinese rivers as a result of agricultural transitions
Strokal, Maryna ; Ma, Lin ; Bai, Zhaohai ; Luan, Shengji ; Kroeze, Carolien ; Oenema, Oene ; Velthof, Gerard ; Zhang, Fusuo - \ 2016
Environmental Research Letters 11 (2016)2. - ISSN 1748-9326
agricultural transitions - China - integrated modeling - nutrient pollution - rivers

Transitions in Chinese agriculture resulted in industrial animal production systems, disconnected from crop production. We analyzed side-effects of these transitions on total dissolved nitrogen (TDN) and phosphorus (TDP) inputs to rivers. In 2000, when transitions were ongoing, 30%-70% of the manure was directly discharged to rivers (range for sub-basins). Before the transition (1970) this was only 5%. Meanwhile, animal numbers more than doubled. As a result, TDN and TDP inputs to rivers increased 2- to 45-fold (range for sub-basins) during 1970-2000. Direct manure discharge accounts for over two-thirds of nutrients in the northern rivers and for 20%-95% of nutrients in the central and southern rivers. Environmental concern is growing in China. However, in the future, direct manure inputs may increase. Animal production is the largest cause of aquatic eutrophication. Our study is a warning signal and an urgent call for action to recycle animal manure in arable farming.

Wild geese of the Yangtze River : their ecology and conservation
Zhang, Y. - \ 2016
University. Promotor(en): Herbert Prins; Fred de Boer; L. Cao. - Wageningen : Wageningen University - ISBN 9789462576049 - 147 p.
geese - anatidae - anser - animal ecology - wildlife management - nature conservation - hydrology - habitat selection - rivers - china - ganzen - dierecologie - wildbeheer - natuurbescherming - hydrologie - habitatselectie - rivieren

Habitat selection is a process in which organisms decide to choose a suitable site for nesting, roosting or foraging. The question where the organisms are, and when they will leave are two of the fundamental questions frequently asked by ecologists. Habitat selection is affected by various abiotic and biotic determinants, varying over different spatial and temporal scales. In addition, an animal’s body size, determining its daily demands and its digestion capacity, plays an important role in foraging and habitat selection. This is because forage quality often decreases with increasing forage quantity. Therefore, herbivores often face a trade-off between forage quality and quantity. Although studies on habitat selection have offered substantial insights into the effect of various ecological factors, myriad effects of habitat and its’ surrounding are still not clearly understood, as former studies concerning this topic normally focus on a single species or a single spatial scale.

Migrating goose species are herbivorous with more or less similar habitat requirements and hence often mix in the field. Studying habitat selection of different goose species is attractive as they are from the same guild but differ in body size. In this thesis, I study the effects of various variables on habitat selection of different Anatidae species over different spatial scales, answering the question how ecological and anthropogenic variables affect Anatidae species habitat selection and population sizes and if these effects vary over different spatial scales.

First, I studied the habitat selection of Anatidae species under the condition with and without interference competition using an experimental approach in Chapter 2. To do this, I offered geese and ducks foraging patches with various swards heights. My results showed that all three species acquired the highest nitrogen intake at relatively tall swards (on 6 or 9 cm, but not on 3 cm) when foraging in single species flocks in the functional response experiment. When they were offered foraging patches differing in sward height with and without competitors, their mean percentage of feeding time did not change, whereas all species increased their percentage of time being vigilant except for the dominant swan goose. All species utilized strategies that increased their peck rate on patches across different sward heights when foraging together with other species, resulting in the same instantaneous and nitrogen intake rate than when foraging in a single species flocks. My results suggest that variation in peck rate over different swards height permits Anatidae herbivores to increase nitrogen intake under competition to compensate for the loss of intake, illustrating the importance of behavioural plasticity in heterogeneous environments when competing with other species for resources.

In Chapter 3, using a correlative field study, I analysed the habitat selection of two differently sized grazing goose species at site level. I found that both species selected lower lying area where the swards became recently exposed, due to receding water levels. However, the smaller species was more sensitive to this elevation gradient. Moreover, sward height negatively affected both species habitat selection with a stronger effect on the smaller species. This result highlighted the importance of body size on facilitating species coexistence and habitat segregation. Not in agreement with the results from most experimental studies, I found that nitrogen content did not influence habitat selection of both species. This conflicting result suggests that additional factors should be carefully considered when applying outcomes from experimental studies to field situations.

In Chapter 4, I studied habitat selection of the two goose species at a lake level by analysing the effect of ecological and anthropogenic variables. My results supported the individual-area relationship as only patch area had a significant effect on both species habitat selection, and other variables that were related to food availability and disturbance, were not significant. In addition, a facilitation effect of grazing livestock on geese habitat selection was detected, indicating that larger grazing herbivores can facilitate geese foraging by removing the taller and lower quality food from the top. As patch area size in wetlands is directly linked to water levels fluctuations, this result demonstrated that modifying hydrological regimes can enlarge the capacity of wetlands for migratory birds.

In Chapter 5, I further expanded my study area to the flood plain level of the Yangtze, testing for the effect of various abiotic and biotic variables on several Anatidae species habitat selection and population trends. I showed that slope and climate factors were the most important ones affecting habitat selection and distribution of Anatidae species. Furthermore, I demonstrated that the current protection policies may not stop the declining population trends but might buffer to some extent against a rapid decline in numbers in wetlands with a higher level protection status. This result points out that the conservation effectiveness is still low and larger conservation efforts are urgently needed to maintain the Anatidae populations, especially in wetlands with a lower level protection status. I recommend several protection measures to stop the decline of Anatidae species in wetlands of the Yangtze River flood plain and I called for more research efforts in this area in particularly, but also at a larger scale, the entire East Asian-Australasian Flyway.

In Chapter 6, I synthesized these results and draw conclusions from the preceding chapters, and highlighted the importance of spatial scales when studying the effect of abiotic and biotic variables on animals’ habitat selection. I also propose to modify hydrological regimes, aimed at creating enhanced habitat and improved forage accessibility conditions over the entire wintering period for herbivorous birds species in the Yangtze River flood plain. In summary, this thesis offers a framework for the effects of various variables on habitat selection and population sizes of herbivorous Anatidae species over different spatial scales, and a scientific basis for policy-makers and managers to enhance the efficiency of conservation actions in wetlands along the Yangtze River flood plain and also for similar ecological systems.

Een evaluatie van de maatlatten R6 en R7 voor de Kader Richtlijn Water
Griffioen, A.B. ; Vries, I. de - \ 2016
IMARES (Rapport / IMARES C087/15) - 28 p.
rivieren - kaderrichtlijn water - waterbeheer - classificatie - waterkwaliteit - aquatische ecologie - monitoring - rivers - water framework directive - water management - classification - water quality - aquatic ecology
De watertypes R6 en R7 in de Kader Richtlijn Water (KRW) classificering verschillen qua grootte van het waterlichaam en structuur. Het watertype R7 staat voor de grote rivieren met een hoofdstroom en nevengeulen. Rivieren als de Rijn, Waal en IJssel zijn hier voorbeelden van. Het watertype R6 staat voor langzaam stromende kleinere rivieren. In de praktijk kunnen beide riviertypen in elkaar overgaan en is het goed mogelijk dat het visbestand een grote overlap kent, maar volgens verschillende maatlatten worden beoordeeld. Dit onderzoek heeft tot doel het inzichtelijk maken van de indeling in beide watertypes. Ook wordt er gekeken naar de verschillen tussen de watertypen R6 en R7.
Toestand vis en visserij in de zoete Rijkswateren 2015 Deel III: Data
Keeken, O.A. van; Hoppe, M. van; Boois, I.J. de; Graaf, M. de; Griffioen, A.B. ; Lohman, M. ; Os-Koomen, E. van; Westerink, H.J. ; Wiegerinck, J.A.M. ; Overzee, H.M.J. van - \ 2016
IJmuiden : Wageningen Marine Research (Rapport / Wageningen Marine Research C116/16) - 543 p.
zoet water - aquatische ecologie - vissen - monitoring - ijsselmeer - randmeren - rivieren - inventarisaties - fresh water - aquatic ecology - fishes - lake ijssel - rivers - inventories
Piekberging en voorraadberging in Rivierenland : een inventarisatie van geschikte gebieden voor piekberging en voorraadberging in het beheergebied van Waterschap Rivierenland
Massop, H.Th.L. ; Jansen, P.C. ; Hattum, T. van; Kwakernaak, C. - \ 2015
Wageningen : Alterra, Wageningen-UR (Alterra-rapport 2685) - 49
wateropslag - waterbeheer - watervoorraden - nederlandse wateren - rivieren - waterverzadiging - gelderland - water storage - water management - water resources - dutch waters - rivers - waterlogging
Alterra Wageningen UR heeft, als een van de partijen in het project RichWaterWorld (RWW), onderzoek gedaan naar piekberging en voorraadberging in Het Waterrijk, een gebied dat onderdeel is van Park Lingezegen dat tussen Arnhem en Nijmegen wordt aangelegd. Omdat door klimaatverandering de kansen op wateroverlast en watertekorten toenemen, is ook elders in Nederland een toenemende behoefte aan bergingsgebieden die kunnen worden ingezet voor piekberging en voorraadberging. Voor Rivierenland is met GIS-bewerkingen geïnventariseerd waar geschikte gebieden voor beide vormen van waterberging liggen.
Dioxines en PCB's in Chinese wolhandkrab; invloed van grootte en variatie door het seizoen
Kotterman, M.J.J. ; Vries, P. de; Leeuwen, S.P.J. van; Hoogenboom, L.A.P. - \ 2015
IMARES Wageningen UR (Rapport / IMARES ) - 43 p.
krabben (schaaldieren) - decapoda - schaaldieren - dioxinen - polychloorbifenylen - rivieren - meren - nederland - crabs - shellfish - dioxins - polychlorinated biphenyls - rivers - lakes - netherlands
De monitoringsstudies naar de vervuilingsgraad van Chinese Wolhandkrab (WHK) die vanaf 2010 in Nederlandse wateren worden uitgevoerd tonen aan dat de WHK sterk vervuild kan zijn met polychloordibenzo-p-dioxines en -furanen (PCDD/F's, verderop aangeduid als 'dioxines'), met dioxine-achtige polychloorbifenylen (dl-PCB's) en met niet-dioxine achtige PCB’s (ndl-PCB’s). Deze contaminanten bevinden zich vooral in het vlees met hoge vetgehalten, de hepatopancreas (= middendarmklier) en gonaden (= geslachtsklier), vaak aangeduid met het 'bruine vlees' uit het lijf. Het witte spiervlees, uit poten, scharen en ook uit het lichaam, is vetarm en de concentraties dioxines en PCB’s zijn laag. Uit de voorgaande onderzoeken blijkt dat er een sterk geografische invloed is op de concentraties contaminanten in WHK; bijvoorbeeld WHK gevangen in de grote rivieren zijn sterker vervuild dan WHK uit het IJsselmeer. Over een eventuele tijdsafhankelijke variatie waardoor bijvoorbeeld gedurende het trekseizoen de concentraties contaminanten in de WHK sterk wisselen op een bepaalde locatie, is nog niets bekend. Er is wel reden om dat aan te nemen. WHK leggen in het trekseizoen grote afstanden af. De kans is daarom reëel dat de WHK die in een bepaald gebied worden gevangen van verschillende locaties afkomstig zijn, waardoor de concentraties contaminanten tussen individuele WHK kunnen verschillen.
Toestand vis en visserij in de Zoete Rijkswateren: 2014 Deel I: Trends van de visbestanden, vangsten en ecologische kwaliteit ratio's
Graaf, M. de; Boois, I.J. de; Griffioen, A.B. ; Overzee, H.M.J. van; Tien, N.S.H. ; Tulp, I.Y.M. ; Vries, P. de; Deerenberg, C.M. - \ 2015
IMARES (Rapport / IMARES C199/15) - 102 p.
zoet water - aquatische ecologie - vissen - monitoring - rivieren - inventarisaties - visserij - visvangsten - vistuig - ijsselmeer - visstand - fresh water - aquatic ecology - fishes - rivers - inventories - fisheries - fish catches - fishing gear - lake ijssel - fish stocks
Het rapport “Toestand Vis en Visserij in de Zoete Rijkswateren” bestaat uit drie verschillende delen: “Trends”, “Methoden” en “Data”. In dit rapport (Deel I) worden (i) de trends in commercieel benutte vissoorten per VBC gebied, (ii) de trends in Habitatrichtlijnsoorten en (iii) de ecologische kwaliteitsratio’s vis gerapporteerd. Hiervoor is gebruik gemaakt van de gegevens die binnen de verschillende vismonitoringsprogramma’s op de Zoete Rijkswateren worden verzameld. In de rapportage zijn trendanalyses voor de verschillende commercieel benutte vissoorten en Habitatrichtlijn vissoorten gemaakt aan de hand van de beschikbare monitoringsgegevens. De gegevens van deze monitoringsprogramma’s worden gebruikt als indicatoren voor de ontwikkeling van de bestanden van de geanalyseerde soorten over verschillende tijdsperioden.
Natuurrealisatie in het programma Ruimte voor de Rivier : Wat zijn de leerpunten van het programma Ruimte voor de Rivier voor combineren vanwater- en natuuropgaven?
Hartgers, E.M. ; Buuren, M. van; Fontein, R.J. ; Hattum, T. van; Lange, H.J. de; Maas, G.J. - \ 2015
Alterra, Wageningen-UR (Alterra-rapport 2687) - 75 p.
rivieren - natuurbescherming - natuurbeheer - natuurontwikkeling - hoogwaterbeheersing - nederland - rivers - nature conservation - nature management - nature development - flood control - netherlands
In het Ruimte voor de Rivier-programma is ruime ervaring opgedaan in het combineren van hoogwaterveiligheidsopgaven met andere doelen, waaronder natuur. Het is een succesvol programma, dat grotendeels op tijd en binnen budget is uitgevoerd, met veel belangstelling vanuit het buitenland. Dit uitvoeringsprogramma is gebruikt om acht sleutelfactoren te identificeren die van belang zijn bij het realiseren van natuur in uitvoeringsprojecten. De acht sleutelfactoren zijn verdeeld over de categorieën Ambitie, Voldoen aan de wet en Daadkracht. Deze sleutelfactoren bevatten diverse aanbevelingen om natuur in toekomstige water gerelateerde uitvoeringsprojecten mee te nemen. Voor toekomstige uitvoeringsprojecten is het van cruciaal belang om in een vroege fase van een project kansen voor win-winsituaties voor natuur en water in beeld te krijgen. Daarbij is het cruciaal dat in het project de ‘dubbeldoelstelling’ natuurrealisatie en waterveiligheid expliciet benoemd wordt. Gezien de tijdsgeest en de insteek van het Deltaprogramma, dat meer dan het Ruimte voor de Rivierprogramma een sectorale insteek kent, is dit een toekomstige uitdaging.
Toestand vis en visserij in de zoete Rijkswateren : Deel II: Methoden
Sluis, M.T. van der; Tien, N.S.H. ; Griffioen, A.B. ; Keeken, O.A. van; Os-Koomen, E. van; Rippen, A.D. ; Wolfshaar, K.E. van de - \ 2015
IJmuiden : IMARES (Rapport / IMARES C193/15) - 88 p.
zoet water - aquatische ecologie - vissen - monitoring - rivieren - inventarisaties - ijsselmeer - visvangsten - visserij - vistuig - fresh water - aquatic ecology - fishes - rivers - inventories - lake ijssel - fish catches - fisheries - fishing gear
Het rapport “Toestand Vis en Visserij in de Zoete Rijkswateren” bestaat uit drie delen. Dit rapport (Deel II) is een achtergronddocument waarin de gebruikte monitoringsmethodieken in de verschillende vis-monitoringen in de zoete Rijkswateren in detail worden beschreven. Meer informatie over trends en vangsten is te vinden in rapportages Deel I: Trends visbestanden, vangsten en ecologische kwaliteit ratio’s en Deel III: Data).
Toestand vis en visserij in de zoete Rijkswateren: 2014 : Deel III: Data
Boois, I.J. de; Hoek, R. ; Graaf, M. de; Griffioen, A.B. ; Keeken, O.A. van; Lohman, M. ; Os-Koomen, E. van; Westerink, H.J. ; Wiegerinck, J.A.M. - \ 2015
IJmuiden : IMARES (Rapport / IMARES C194/15) - 511 p.
zoet water - aquatische ecologie - vissen - monitoring - rivieren - inventarisaties - ijsselmeer - visvangsten - visserij - vistuig - fresh water - aquatic ecology - fishes - rivers - inventories - lake ijssel - fish catches - fisheries - fishing gear
Dit rapport bevat een overzicht van de gegevens verzameld tijdens de vismonitoringen in de zoete rijkswateren. Het omvat de volgende bemonsteringen: - Open water vismonitoring IJssel- en Markermeer met actieve vistuigen - Oever vismonitoring IJssel- en Markermeer met actieve vistuigen - Vismonitoring in IJssel- en Markermeer met kieuwnetten - Diadrome vis Kornwerderzand Waddenzee op basis van fuikregistraties - Vismonitoring grote rivieren met actieve vistuigen - Vismonitoring zoete rijkswateren op basis van vangstregistratie aalvissers - Diadrome vismonitoring zoete rijkswateren op basis van fuikregistraties (sinds najaar 2012) - Vismonitoring grote rivieren op basis van zalmsteekregistraties - Vismonitoring randmeren met actieve vistuigen - Monitoring glasaal op intreklocaties.
Bruinvis volgt spiering naar westerschelde
Ramaker, R. ; Leopold, M.F. - \ 2015
Resource: weekblad voor Wageningen UR 10 (2015)8. - ISSN 1874-3625 - p. 9 - 9.
phocoenidae - milieubeleid - westerschelde - habitats - habitatgeschiktheid - osmerus - rivieren - wilde dieren - populatie-ecologie - environmental policy - western scheldt - habitat suitability - rivers - wild animals - population ecology
In de Westerschelde zwemmen voor het eerst in decennia weer bruinvissen. De dieren jagen op de eveneens teruggekeerde trekvis spiering. Het is een succesverhaal van het Nederlands milieubeleid, zegt Mardik Leopold, onderzoeker van Imares Wageningen UR, die vandaag promoveert op onderzoek naar het eetgedrag van bruinvissen.
Reguleringsmechanismen in het kustecosysteem van de Voordelta
Kooten, T. van; Jansen, H.M. - \ 2015
IJmuiden : IMARES (Rapport / IMARES C095/15) - 66
aquatische ecosystemen - benthos - voordelta - kustwateren - zuidwest-nederland - aquatische gemeenschappen - visserij - bodemfauna - rivieren - aquatic ecosystems - coastal water - south-west netherlands - aquatic communities - fisheries - soil fauna - rivers
Wordt het benthos in het Voordelta kustecosysteem gereguleerd door bottom-up of top-down gerelateerde processen, en hoe zal dit systeem reageren op de maatregelen om de bodemberoerende visserij uit te sluiten in het Bodembeschermingsgebied.
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