NHI 2.1 Veranderingen in NHI

Dit document is een concept en uitsluitend bedoeld voor discussiedoeleinden. Een impuls is gegeven aan het verbeteren van het nationaal hydrologisch instrumentarium, NHI 2.0. NHI 2.0 voldeed in 2010 nog niet volledig aan de wensen van RWS. In 2010 hebben twee processen plaatsgevonden, die tot meer inzicht hebben geleid in de prestaties van het NHI. Ten eerste de regionale toetsing van het NHI, onder andere door STOWA, en ten tweede het gebruik van NHI in diverse regionale en landelijke studies voor Zoetwaterverkenning (ZWV). Als gevolg hiervan zijn in NHI 2.1, in opdracht van de RWS Waterdienst, veel verbeteringen doorgevoerd

Tailoring information about climate change and its impacts

Resultaten van onderzoek naar klimaatverandering en de mogelijke effecten zijn vaak niet beschikbaar in een vorm waarin ze direct door anderen gebruikt kunnen worden. Gebruikers van klimaat- en impactinformatie hebben vaak ook geen goed overzicht over de beschikbare gegevens van alle sectoren en resultaten zijn soms inconsistent

Uncertainty estimation of end-member mixing using generalized likelihood uncertainty estimation (GLUE), applied in a lowland catchment

End-member mixing models have been widely used to separate the different components of a hydrograph, but their effectiveness suffers from uncertainty in both the identification of end-members and spatiotemporal variation in end-member concentrations. In this paper, we outline a procedure, based on the generalized likelihood uncertainty estimation (GLUE) framework, to more inclusively evaluate uncertainty in mixing models than existing approaches. We apply this procedure, referred to as G-EMMA, to a yearlong chemical data set from the heavily impacted agricultural Lissertocht catchment, Netherlands, and compare its results to the traditional end-member mixing analysis (EMMA). While the traditional approach appears unable to adequately deal with the large spatial variation in one of the end-members, the G-EMMA procedure successfully identified, with varying uncertainty, contributions of five different end-members to the stream. Our results suggest that the concentration distribution of effective end-members, that is, the flux-weighted input of an end-member to the stream, can differ markedly from that inferred from sampling of water stored in the catchment. Results also show that the uncertainty arising from identifying the correct end-members may alter calculated end-member contributions by up to 30%, stressing the importance of including the identification of end-members in the uncertainty assessment

Optimal design of multi-channel microreactor for uniform residence time distribution

Multi-channel microreactors can be used for various applications that require chemical or electrochemical reactions in either liquid, gaseous or multi phase. For an optimal control of the chemical reactions, one key parameter for the design of such microreactors is the residence time distribution of the fluid, which should be as uniform as possible in the series of microchannels that make up the core of the reactor. Based on simplifying assumptions, an analytical model is proposed for optimizing the design of the collecting and distributing channels which supply the series of rectangular microchannels of the reactor, in the case of liquid flows. The accuracy of this analytical approach is discussed after comparison with CFD simulations and hybrid analytical-CFD calculations that allow an improved refinement of the meshing in the most complex zones of the flow. The analytical model is then extended to the case of microchannels with other cross-sections (trapezoidal or circular segment) and to gaseous flows, in the continuum and slip flow regimes. In the latter case, the model is based on second-order slip flow boundary conditions, and takes into account the compressibility as well as the rarefaction of the gas flow

Zoetwatervoorziening in Nederland : landelijke analyse knelpunten in de 21e eeuw

Deze knelpuntenanalyse is een eerste stap in een verkenning van de zoetwaterproblematiek. Doel van de landelijke knelpuntenanalyse is om vast te stellen waar de toekomstige watervraag groter is dan de waterbeschikbaarheid, hetzij qua hoeveelheid, hetzij qua kwaliteit. Daartoe is de watervraag van diverse gebruikers in beeld gebracht, evenals de waterbeschikbaarheid, nu en in de toekomst. Voor het verkennen van de toekomst is gebruik gemaakt van deltascenario's

Complex conductivity of soils

The complex conductivity of soils remains poorly known despite the growing importance of this method in hydrogeophysics. In order to fill this gap of knowledge, we investigate the complex conductivity of 71 soils samples (including four peat samples) and one clean sand in the frequency range 0.1 Hz to 45 kHz. The soil samples are saturated with six different NaCl brines with conductivities (0.031, 0.53, 1.15, 5.7, 14.7, and 22 S m21, NaCl, 258C) in order to determine their intrinsic formation factor and surface conductivity. This data set is used to test the predictions of the dynamic Stern polarization model of porous media in terms of relationship between the quadrature conductivity and the surface conductivity. We also investigate the relationship between the normalized chargeability (the difference of in-phase conductivity between two frequencies) and the quadrature conductivity at the geometric mean frequency. This data set confirms the relationships between the surface conductivity, the quadrature conductivity, and the normalized chargeability. The normalized chargeability depends linearly on the cation exchange capacity and specific surface area while the chargeability shows no dependence on these parameters. These new data and the dynamic Stern layer polarization model are observed to be mutually consistent. Traditionally, in hydrogeophysics, surface conductivity is neglected in the analysis of resistivity data. The relationships we have developed can be used in field conditions to avoid neglecting surface conductivity in the interpretation of DC resistivity tomograms. We also investigate the effects of temperature and saturation and, here again, the dynamic Stern layer predictions and the experimental observations are mutually consistent

Opties voor een klimaatbestendige zoetwatervoorziening in Laag Nederland, tussentijds integratierapport

Dit rapport geeft een tussentijds overzicht van ‘state of the art’ kennis uit lopend onderzoek van het consortium ‘Climate Proof Fresh Water Supply’ (CPFWS) dat in het kader van het onderzoeksprogramma Kennis voor Klimaat wordt uitgevoerd. De focus van dit onderzoek naar een klimaatbestendige zoetwatervoorziening ligt op lokale en regionale oplossingen in Laag Nederland voor land- en tuinbouw en natuur. De zoetwatervoorziening van dit gebied wordt naast droogte vooral bedreigd door verzilting van grond- en oppervlaktewater. In zes samenhangende werkpakketten wordt geanalyseerd hoe dit gebied meer zelfvoorzienend kan worden én hoe aanpassingen in het (hoofd)watersysteem kunnen bijdragen aan de watervoorziening van het gebied. Centraal in de aanpak zijn een 3-tal casestudies in de Hotspots Haaglanden, Rotterdam Regio en Zuidwestelijke delta

Balancing supply and demand of fresh water under increasing drought and salinisation in the Netherlands

The latest climate impact assessments show that climate change will cause an increasing mismatch between demand and supply of fresh water in many densely populated deltas around the world. Recent studies for the Netherlands show that the current water supply strategy is not climate proof in the long-run. Therefore, a future ‘climate proof’ fresh water supply is national priority on the Dutch water policy agend

The Nature, Extent, and Significance of Consumer Credit in the United States

The economic institution of Credit touches the life of every American. He may believe cash payment, he may even make a sustained, conscious effort toward this end, but if he is employed or an employer, if he sells or buys, if he makes use of any produced good or service, he benefits from, and must pay for, some part of the credit system

Zoetwater zelfvoorzienendheid van de landbouw: Deltafact

Deze Deltafact gaat over de zoetwater zelfvoorzienendheid van de landbouw in Nederland en de verschillende technieken die daar aan bijdragen