Exploring pathways for sustainable water management in river deltas in a changing environment

Exploring adaptation pathways into an uncertain future can support decisionmaking in achieving sustainable water management in a changing environment. Our objective is to develop and test a method to identify such pathways by including dynamics from natural variability and the interaction between the water system and society. Present planning studies on long-term water management often use a few plausible futures for one or two projection years, ignoring the dynamic aspect of adaptation through the interaction between the water system and society. Our approach is to explore pathways using multiple realisations of transient scenarios with an Integrated Assessment Meta Model (IAMM). This paper presents the first application of the method using a hypothetical case study. The case study shows how to explore and evaluate adaptation pathways. With the pathways it is possible to identify opportunities, threats, timing and sequence of policy options, which can be used by policymakers to develop water management roadmaps into the future. By including the dynamics between the water system and society, the influence of uncertainties in both systems becomes clearer. The results show, among others, that climate variability rather than climate change appears to be important for taking decisions in water management

Effect analysis of transient scenarios for successful water management strategies

Recent scenario studies on water management focus on one or two projection years and the effects on the water system and functions. The future is however more complex and dynamic. Therefore, we analyse transient scenarios in order to evaluate the performance of water management strategies. Current available simulation tools are not suitable for this purpose. Therefore, we have developed and used a tool to simulate 50-100 year long time series and that is good and fast enough to simulate the effects of these scenarios and strategies on the water system and the interaction with the human system. We present the first step by means of a case study

Kunstmest duur? Strooi minder!

In het verleden heeft de Commissie Bemesting Grasland en Voedergewassen het stikstofbemestingsadvies op grasland vastgesteld op basis van prijzen van veevoeders en kunstmest. Uitgangspunt was dat bemesten niet meer kost dan het oplevert. Prijzen variëren, maar de commissie stelt niet ieder jaar een nieuw stikstofbemestingsadvies vast. U kunt zelf wel rekening houden met variaties in prijzen. In dit artikel wordt uitgelegd hoe

Perspectieven voor langzaam groeiende kuikens in Nederland? Ja, mits

In het eindrapport van de 'Stuurgroep Heroriëntatie Pluimveehouderij' (1999) wordt aanbevolen te onderzoeken of het mogelijk is een alternatief kuiken op de markt zetten. Met alternatief kuiken wordt een kuiken bedoeld met een lagere groeisnelheid danhet huidige kuiken, maar hoger dan het biologische of 'label'kuiken. Oftewel: een product tussen het huidige kuiken en het biologische of 'label'kuiken. Het Praktijkcentrum Het Spelderholt heeft daarom een proef verricht waarbij getracht is een beeld te vormen van de consequenties van een eventuele overschakeling van het huidige kuiken naar een langzaam groeiend kuiken

Sediment management and the renewability of floodplain clay for structural ceramics

The Netherlands has vast resources of clay that are exploited for the fabrication of structural ceramic products such as bricks and roof tiles. Most clay is extracted from the so-called embanked floodplains along the rivers Rhine and Meuse, areas that are flooded during high-discharge conditions. Riverside clay extraction is-at least in theory-compensated by deposition. Based on a sediment balance (deposition versus extraction), we explore the extent to which clay can be regarded as a renewable resource, with potential for sustainable use. Beyond that, we discuss the implications for river and sediment management, especially for the large engineering works that are to be undertaken to increase the discharge capacities of the Rhine and Meuse. Extraction rates are based on production statistics for clay, as well as those for fired end-products. Deposition rates are estimated from published and unpublished geological data (clay volumes and thicknesses, datings, etc.) and from morphological modeling studies. Comparisons between extraction and deposition are made at three different time-space scales: (1) long term (post-1850)/large scale (all Dutch floodplains), (2) present/large scale, and (3) present/site scale. The year 1850 is relevant because it approximately marks the beginning of the current, fully engineered river systems, in which depositional processes are constrained by dikes and groynes. As the Industrial Revolution began in the same period, post-1850 sediments can be identified by their pollution with heavy metals. (1) We estimate the post-1850 clay volume in situ at about 0.20 km(3), and the total extracted volume in the same period at about 0.17 km(3). This puts the net long-term average deposition rate of clay at similar to 1.3 million m(3)/year and the corresponding extraction rate at similar to 1.1 million m(3)/year. (2) Current accumulation is approximately 0.4 million m(3)/year and expected to increase, and current extraction is about 0.7 million m(3)/year and expected to decrease. (3) Clay extraction creates a depression that has an increased sediment-trapping efficiency. This local effect is not considered explicitly in large-scale morphological modeling. Based on maximum observed sedimentation rates, we estimate that replenishment of a clay site takes in the order of 150 years. As clay extraction lowers some 0.5 km(2) of floodplain yearly, a surface area of approximately 75 km(2) would be required for sustainable clay extraction. This is about 1/6 of the total surface area of the embanked floodplains. On the long term, clay extraction from the embanked floodplain depositional environment has been sustainable. At strongly decreasing deposition rates, the ratio between extraction and replenishment seems to have shifted towards unsustainable. However, current sedimentation is estimated conservatively. The site-scale approach suggests that, even if extraction would currently exceed deposition, this could be resolved with sediment management, that is, with site restoration measures aimed at higher sediment-trapping efficiency. Our results have implications for river engineering, especially where substantial digging is involved (floodplain lowering, high-discharge bypass channels, obstacle removal). First, this inevitably affects the clay resources that we studied, while resource sterilization should be avoided. Secondly, the effect that any form of digging has on subsequent sedimentation-increased rates-relates to long-term river maintenance. We conclude that floodplain clay is a renewable resource, especially if managed accordingly. Beyond that, we established that clay extraction is a significant, lasting factor in floodplain evolution along the Rhine and Meuse Rivers. The interests of the extractive industry and river managers could be served jointly with sediment management plans that are based on sediment-budget analyse

Becoming Walata: A History of Saharan Social Formation and Transformation

Strooisel moet rul en droog zijn, maar dat is niet het enige , blijkt uit PP onderzoek

Strooiselbeluchting geeft minder ammoniak maar meer stof

Het beluchten van mest draagt in de pluimveehouderij bij aan de reductie van de ammoniakemissie. Dit blijkt onder andere uit het aantal systemen met een Groen Label waarbij deze techniek wordt toegepast. Ook het beluchten van strooisel geeft een reductie van de ammoniakemissie. Een negatief effect hierbij is echter dat de arbeidsomstandigheden verslechteren door een circa vijf keer hogere stofconcentratie

Linking Flow Regime, Floodplain Lake Connectivity and Fish Catch in a Large River-Floodplain System, the Volga-Akhtuba Floodplain (Russian Federation)

River-floodplain systems are amongst the most productive—but often severely impacted—aquatic systems worldwide. We explored the ecological response of fish to flow regime in a large river-floodplain system by studying the relationships between (1) discharge and inundated floodplain area, with a focus on spatial and temporal patterns in floodplain lake connectivity, and (2) flood volume and fisheries catch. Our results demonstrate a non-linear relationship between discharge and floodplain inundation with considerable hysteresis due to differences in inundation and drainage rate. Inundation extent was mostly determined by flood volume, not peak discharge. We found that the more isolated lakes (that is, lakes with a shorter connection duration to the river) are located at higher local elevation and at larger hydrological distance from the main rivers: geographical distance to the river appears a poor predictor of lake isolation. Although year-to-year fish catches in the floodplain were significantly larger with larger flood volumes in the floodplain, they were not in the main river, suggesting that mechanisms that increase catch, such as increased floodplain access or increased somatic growth, are stimulated by flooding in the floodplain, but not in the river. Fish species that profit from flooding belong to different feeding guilds, suggesting that all trophic levels may benefit from flooding. We found indications that the ecological functioning of floodplains is not limited to its temporary availability as habitat. Refugia can be present within the floodplain itself, which should be considered in the management of large rivers and their floodplain

Yukawa Potential Orbital Energy: Its Relation to Orbital Mean Motion as well to the Graviton Mediating the Interaction in Celestial Bodies

Research on gravitational theories involves several contemporary modified models that predict the existence of a non-Newtonian Yukawa-type correction to the classical gravitational potential. In this paper we consider a Yukawa potential and we calculate the time rate of change of the orbital energy as a function of the orbital mean motion for circular and elliptical orbits. In both cases we find that there is a logarithmic dependence of the orbital energy on the mean motion. Using that, we derive an expression for the mean motion as a function of the Yukawa orbital energy, as well as specific Yukawa potential parameters. Furthermore, various special cases are examined. Lastly, expressions for the Yukawa range and coupling constant are also derived. Finally, an expression for the mass of the graviton mediating the interaction is calculated using the expression its Compton wavelength (i.e., the potential range ).Numerical estimates for the mass of the graviton mediating the interaction are finally obtained at various eccentricity values and in particular at the perihelion and aphelion points of Mercury’s orbit around the sun