Mapping trends in water table depths in a brazilian cerrado area

Abstract The Cerrado region is the most extensive woodland-savanna

Communiceren van statistische informatie over onzekerheid in het tactisch-strategische waterkwantiteitsbeheer

Om doelmatige beslissingen te kunnen nemen hebben waterschappen voortdurend informatie nodig over de toestand van het watersysteem in hun beheergebied. Hiervoor wordt gemonitord, onderzoek gedaan, worden (model)berekeningen gemaakt en worden op basis daarvan adviezen voor investeringen voorgelegd aan het bestuur. De basis van deze adviezen is veelal geen hard cijfer, maar een getal dat omgeven is met inschattingen en onzekerheden. Zo bestaat dé opgave voor wateroverlast in de vorm van een hard getal in kuubs of hectares niet, maar is dit een inschatting met een bepaalde onzekerheid, zeker als om lange tijdsperioden tot 2050 gaat. In deze studie is onderzocht hoe over onzekerheden gecommuniceerd wordt richting bestuurders, met als casus de wateropgave voor wateroverlast

How much would it cost to monitor farmland biodiversity in Europe?

International audienceTo evaluate progress on political biodiversity objectives, biodiversity monitoring provides information on whether intended results are being achieved. Despite scientific proof that monitoring and evaluation increase the (cost) efficiency of policy measures, cost estimates for monitoring schemes are seldom available, hampering their inclusion in policy programme budgets. Empirical data collected from 12 case studies across Europe were used in a power analysis to estimate the number of farms that would need to be sampled per major farm type to detect changes in species richness over time for four taxa (vascular plants, earthworms, spiders and bees). A sampling design was developed to allocate spatially, across Europe, the farms that should be sampled. Cost estimates are provided for nine monitoring scenarios with differing robustness for detecting temporal changes in species numbers. These cost estimates are compared with the Common Agricultural Policy (CAP) budget (2014-2020) to determine the budgetallocation required for the proposed farmland biodiversity monitoring. Results show that the bee indicator requires the highest number of farms to be sampled and the vascular plant indicator the lowest. The costs for the nine farmland biodiversity monitoring scenarios corresponded to 001%-074% of the total CAP budget and to 004%-248% of the CAP budget specifically allocated to environmental targets.Synthesis and applications. The results of the cost scenarios demonstrate that, based on the taxa and methods used in this study, a Europe-wide farmland biodiversity monitoring scheme would require a modest share of the Common Agricultural Policy budget. The monitoring scenarios are flexible and can be adapted or complemented with alternate data collection options (e.g. at national scale or voluntary efforts), data mobilization, data integration or modelling efforts. Editor's Choic

Kartering grondwaterspiegeldiepte in laag Friesland : Actualisatie van een deel van het grondwaterspiegeldieptemodel van de Basisregistratie Ondergrond (BRO)

The aim of this project is to make up-to-date maps of three water table depth properties – average highest groundwater level (GHG), average lowest groundwater level (GLG) and water table class (Gt) – in the low-lying Holocene part of the province of Friesland, and to quantify the accuracy of these maps. This project is therefore a step in the development of a Water Table Depth Model (WDM) for the whole country, which will become available from 2022 via the National Key Registry of the Subsurface (BRO). The WDM has many uses, including for spatial and land use planning, calculation of crop damage, habitat restoration/creation, designation of special areas of conservation (EU Habitats Directive), supporting applications for derogation under the EU Nitrates Directive and the assessment of effectiveness and risks of plant protection products. The mapping in Friesland was carried out using a stratified simple random sampling design based on soil conditions, field drainage and distance to ditches. In 2019 and 2020, at a total of 296 locations water table depths were measured and soil profile descriptions were drawn up. Based on these data, maps of the average highest groundwater level (GHG), average lowest groundwater level (GLG) and water table class (Gt) were made

Physical basis of time series models for water table depths

The relationship between precipitation excess and water table depth can be described by empirical time series models such as transfer function noise models, autoregressive exogenous variable models (ARX), and threshold autoregressive self-exciting open loop models. In this paper these models are interpreted in terms of the water balance of a soil column. A physically based ARX model is used to predict the effect of an intervention on the water table dynamics at two locations. It is shown that the physically based ARX model predicts the effect of interventions reasonably well

Vegetatieopnamen als meetnet voor de vochttoestand?

Grondwaterstanden geven informatie over de vochttoestand van de bodem, maar de samenstelling van natuurlijke vegetaties levert ook informatie hierover. Als beide methoden naast elkaar kunnen worden gebruikt, vergroot dat het meetnet om de vochttoestand te volgen. Potentieel zijn dan duizenden grondwatermeetpunten en tienduizenden vegetatieopnamen op interessante plekken beschikbaar. In dit rapport zijn de gemiddelde voorjaarsgrondwaterstanden (GVG’s) die uit grondwatermeetreeksen zijn afgeleid, vergeleken met de GVG’s die op dezelfde plek op vijf manieren uit de vegetatiesamenstelling zijn berekend: de lineaire en de exponentiële Ellenbergmethode (SynBioSys), Iteratio, Abiotic Indicators en Estar

Kan de efficiëntie van karteren worden vergroot met behoud van kwaliteit? : Onderzoek naar een nieuwe karteerstrategie om gewasopbrengstderving in grondwaterwinningsgebieden te bepalen

Om de landbouwschade (in de vorm van gewas-opbrengstderving) als gevolg van grondwaterwinning te berekenen, maakt de ACSG (Adviescommissie Schade Grondwater) gebruik van onder andere een gedetailleerde bodem- en grondwatertrappenkaart. Het vervaardigen van deze kaarten is specialistenwerk en kost tijd. Omdat het aantal én de omvang van de landbouwschadeprojecten toenemen, is er behoefte aan een karteermethode met een kortere doorlooptijd. Het doel van deze opdracht is om een aantal alternatieve karteerscenario’s te ontwikkelen die een kortere doorlooptijd hebben en om de nauwkeurigheid en efficiëntie ten opzichte van de huidige methode te analyseren. Voor elk scenario is de opbrengstderving als gevolg van de waterwinning berekend met Waterwijzer Landbouw. De scenarioresultaten zijn vervolgens ten opzichte van de huidige methode geanalyseerd met behulp van een kosten-batenanalyse

Physical basis of time series models for water table depths

The relationship between precipitation excess and water table depth can be described by empirical time series models such as transfer function noise models, autoregressive exogenous variable models (ARX), and threshold autoregressive self-exciting open loop models. In this paper these models are interpreted in terms of the water balance of a soil column. A physically based ARX model is used to predict the effect of an intervention on the water table dynamics at two locations. It is shown that the physically based ARX model predicts the effect of interventions reasonably well

Mapping water table depths in wetlands and polder areas by probability sampling

Information on water table depth (WTD) in polder areas and wetlands is important in, for example, estimating emissions of greenhouse gases, assessing the agricultural and ecological potential, and flood risk management. The seasonal variation of WTDs is summarized with averages of the yearly highest (shallowest) and lowest (deepest) water tables (MHW and MLW). These characteristics show short-distance variations within the fields in polder areas, which cannot be mapped using geostatistical interpolation techniques or physical modelling against reasonable costs or with acceptable accuracy. The within-field variations depend on soil type and water management. MHW and MLW were determined from auger hole measurements of WTDs at locations being selected following stratified simple random sampling in subareas classified by soil type and water management. Within these subareas, a further classification was made on the basis of distance to ditches. For each subarea spatial distribution functions of MHW and MLW were made, taking censored observations into account. Uncertainty was quantified by 10,000 bootstrap realisations of the spatial distribution functions. From these realisations maps depicting summary statistics for the spatial distribution of WTD-characteristics within the subareas were derived, as well as a map with probabilities of exceedance of a critical level that can serve as input for risk analysis

Analyse verdroging zeven TOP-gebieden in de provincie Utrecht

For seven TOP areas in the province of Utrecht an analysis was made of the extent to which these areas meet standards of water table depth and groundwater quality. This so called target realisation was compared with the situation in 2013. The results of the analysis indicated that desiccation has more or less been reduced. However, it has also been shown that conditions could have been created that are too wet to meet the abiotic standards for the nature types being pursued