Wijzigingsvoorstel op Aquo-Lex HarmoniQua glossary

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1 Wijzigingsvoorstel op Aquo-Le HarmoniQua glossary Indiener OpenMI Datum Versie 1.0 Kenmerk

2 Documentbeheer Wijzigingshistorie Datum Auteur Versie Wijziging H-J. Lekkerkerk 1.0 Reviewers Naam Functie Distributie Eemplaar Naam Locatie Documenten / Bronnen Bronnen: 1. Richtlijn voor het opstellen van een wijzigingsvoorstel op AquoLe, IDsW, maart AquoLe versie juni 2006, IDsW, juni HarmoniQua glossary, OpenMI van 85

3 Inhoudsopgave DOCUMENTBEHEER 2 MOTIVATIE 4 AANLEIDING 4 BUSINESS CASE 4 WIJZIGINGSVOORSTEL 5 VERTAALDE BEGRIPPEN 5 BEGRIPPEN ZONDER VERTALING 42 POTENTIELE WIJZIGINGEN van 85

4 Motivatie Aanleiding Dit wijzigingsvoorstel is geen voorstel in de reguliere zin. Achterliggende reden is dat OpenMI als nieuwe standaard in Aquo wordt ingebracht. Ten gevolge hiervan wordt ook de HarmoniQua glossary meegeleverd. Deze begrippenlijst is in het Engels opgesteld en dient voor een duidelijke begripsvorming in de hydrologische modellenwereld. Hoewel HarmoniQua / OpenMI als zodanig een nieuwe standaard is, heeft de begrippenlijst wel degelijk impact op een onderdeel van Aquo, namelijk AquoLe. Hierin zijn in juni 2006 de begrippen uit de hydrologische begrippenlijst overgenomen waardoor overlap ontstaat tussen beide lijsten. Dit voorstel is dan ook nog niet direct een voorstel tot inpassing in AquoLe, aangezien dit lastig is met engelstalige termen. Dit voorstel is eerder een verzoek aan de waterbeheerders uit het hydrologische domein om kritisch te kijken naar de vertaling van begrippen naar het Nederlands en de eerste inpassing daarvan in AquoLe. Business Case Voordelen nieuwe definities Toegepast in een Europees project en daarmee ook Europa breed afgestemd. Daarnaast een toevoeging van een groot aantal termen die nog niet in AquoLe voorkomen. Afbakening De lijst beperkt zich tot het HarmoniQua project Impact Bij acceptatie van de huidige lijst groot, aangezien er veel overlap (ca 300 begrippen) is met de huidige hydrologische begrippen van 85

5 Wijzigingsvoorstel Vertaalde begrippen Naam Engels Afkorting Synoniem Begrip Description Abiotic Abiotisch Pertaining to the non-biological (e.g. physical and chemical) factors which affect ecosystems and populations or characterized by the absence of life or living organisms. Absorption Absorptie Assimilation of molecules or other substances into the physical structure of a liquid or solid without chemical reaction. An eample is the absorption of water into soil. Accuracy Nauwkeurigheid Closeness of computations, estimates or measurements to the eact or true values. Activity Activiteit Each task in HarmoniQuA is decomposed into a number of activites comprising descriptions of things to be done within the specific tasks. Actual evapotranspiration actuele evapotranspiratie The combination of evaporation from soils and water surface, and transpiration from vegetation. By definition actual evapotranspiration is less than or equal to the current potential evapotranspiration. Actual evapotranspiration varies with soil properties, soil moisture and vegetation Acute toicity Acute toiciteit Severe biological harm and, often, mortality of organisms that have been affected by the properties of a substance, such as contaminated sediment. The acute toicity is determined by quantifying the mortality of appropriate sensitive organisms that are e Adaptation aanpassing A genetically determined characteristic that enhances an organism's ability to cope with its environment. Adsorption Adsorptie Adhesion of an etremely thin layer of molecules (as of gas, solids or liquids) to the surface of solid or liquids with which they are in contact. Advection Advectie The process by which the solutes are transported by motion of the flowing groundwater Aerobic bacteria Aerobe bacterien Aerobic bacteria refer to the bacteria that oidize substrate (feed) by oygen respiration and live on the energy generated in the process. Aerobic bacteria are the opposite of anaerobic bacteria, which need no oygen gas. Aerobic bacteria play an import Agricultural pollution landbouw gerelateerde vervuiling The liquid and solid wastes from farming, including runoff from pesticides, fertilizers and feed-lots; erosion and dust from ploughing; animal manure, crop residues and debris. Agrochemicals landbouw chemicalieen All chemicals used in agriculture (pesticides, herbicides, etc.). Air Chamber Luchtkamer Air Chambers contain compressed air which prevent very low minimum pressures in the pipeline and hence column separation. They are frequently used behind the pumps in water supply pipelines. Mostly they are cylindrical with a vertical and/or horizontal ais. A horizontal cylinder may be preferred for a very long pipeline when a large volume of air is required Alarm level alarmeringspeil Water level (stage) at, or approaching, flood level which is considered to be dangerous and at which warnings should be commenced. Algae Algen One-celled or many-celled plants that have no root, stem or leaf systems. Simple plants. See Phytoplankton. Algal bloom Algenbloei A sudden growth of algae in an aquatic ecosystem, a characteristic symptom of eutrophication. It can occur naturally in spring or early summer when primary production eceeds consumption by aquatic herbivores. Algal blooms may also be induced by nutrient Algorithm Algoritme A precise rule (or set of rules) for solving a problem. Alkalic waste water alkalisch afvalwater Alkalic waste water refers to waste liquids discharged from factories, etc., that contain high-concentration of caustic alkali or calcium hydroide. Alkalic waste water is either collected for reuse or disposed of; the latter case requires neutralization Alkalinity alkaliteit The measurable ability of solutions or aqueous suspensions to neutralize an acid. Alkyl mercury alkylkwik Alkyl mercury is organic mercury which is the alleged cause of Minamata Disease. Symptoms of alkyl mercury poisoning include central nervous disorders, such as perceptive, hearing and speech disorders, paralyzed limbs, and even death. Alkyl mercury could Alluvium aanspoeling Sediments (clays, silts, sands, gravels and other materials) deposited by flowing water. Deposits can be made by streams van 85

6 Naam Engels Afkorting Synoniem Begrip Description on river beds, floodplains and alluvial fans. Ambient omgeving Usual or surrounding conditions of temperatures, humidity, etc. Ammonia nitrogen NH4-N ammoniak stikstof Nitrogen is an essential element contained in protein that constitutes plants and animals. Ammonia nitrogen, the first nitrogen of inorganic form generated from the decomposition of plants and animals (organic matter), serves as an effective inde of wate Amortization Afschrijving Procedure of a firm or company setting aside funds to replace capital equipment when it becomes obsolete. Anaerobic (respiration) anaerobe ademhaling Oidation occurring in the absence of free or dissolved oygen often facilitated by specific bacterial strains, e.g. methane producing bacteria present during the anaerobic digestion of sewage sludge. Protozoans may carry on respiration this way, as well. Anaerobic bacteria Anaerobe bacterieen Anaerobic bacteria refer to the bacteria that grow without dissolved oygen. The decomposition of organic substances by anaerobic bacteria produces hydrogen sulphide, ammonia, methane and low molecular fatty acid. The process of digestion by anaerobic bac Analysis, dimensional dimensionele analylse Drawing conclusions by considering the dimensions of the various terms in the equation describing a physical process. Analytical model Analytisch model A models that can be solved mathematically in closed form. For eample, some model algorithms that are based on relatively simple differential equations can be solved analytically to provide a single solution. Ancillary Data bijkomende gegevens Data on ancillary structures, such as combined sewer overflows, bifurcations, tanks, control structures and pumping stations, can profoundly affect the results of a sewer model. Anisotropy Anisotroop The condition under which one or more hydraulic properties at any point within the groundwater flow system vary with the direction of measurement. Annual Rainfall Time Series jaarlijkse neerslag tijdreeks This is a series of storms etracted from a rainfall record which represent a typical years rainfall. Anoic Anoisch Deficient in or lacking oygen. Antecedent precipitation inde inde van voorafgaande neerslag Weighted summation of past daily precipitation amounts, used as an inde of soil moisture. The weight given to each day's precipitation is usually assumed to be an eponential or reciprocal function of time, with the most recent precipitation receiving the greatest weight. Anthropogenic antropogeen Refers to the influence of human activities on natural systems. Aphotic afotisch Without light. Applied hydro-ecology toegepaste hydro-ecologie The linkage of knowledge from hydrological, hydraulic, geomorphological and biological/ecological sciences to predict the response of freshwater biota and ecosystems to variation of abiotic factors over a range of spatial and temporal scales. Aquiclude acquiclude A saturated geological unit that is incapable of transmitting significant quantities of water under ordinary hydraulic gradients. Aquifer aquifer A saturated permeable geological unit that can transmit significant quantities of water under ordinary hydraulic gradients. Aquifer, confined afgesloten aquifer An aquifer that is overlain by a low permeability layer. Aquifer, perched zwevende watervoerende A saturated lense that is bounded (overlain and underlain) by unsaturated conditions. This is a special type of an laag unconfined aquifer. Aquifer, unconfined aquifer met freatisch water An aquifer that contains the water table and is normally eposed to the groundsurface. There may be a low permeability layer overlying the aquifer protecting it from the surface. Aquitard aquitard A relatively low-permeable layer or bed in a stratigraphic sequence. These layers may be permeable enough to transmit water in quantities that are significant in the study of regional groundwater flow, but their permeability is not sufficient to allow the Areal precipitation neerslag per oppervlakte Precipitation in a specific area epressed as the average depth of liquid water over this area. Artesian bores artesische boring Bores having a static water level (head) above the top of the aquifer being tapped. If the head is above the ground surface, the bore is free flowing, unless capped. Artesian conditions Artesische Conditions where the hydraulic head in a confined aquifer rises above the top of the aquifer. omstandigheden Asbestos Asbest A mineral fibre that can pollute air or water and cause cancer or asbestosis when inhaled. Its use has been banned or severely restricted by many countries van 85

7 Naam Engels Afkorting Synoniem Begrip Description Assimilation Assimilatie The ability of a body of water to purify itself of pollutants. Assimilative capacity vermogen tot assimilatie The capacity of a natural body of water to receive (i) waste-waters, without harmful effects; (ii) toic materials, without damage to aquatic life or humans who consume the water; (iii) Biological Oygen Demand (BOD), within prescribed dissolved oygen li auditor reviewer auditor A person that is conducting some kind of review of a modelling study. The review may be more or less comprehensive depending on the requirements of the particular case. The auditor is typically appointed by the water manager to support the water manager to match the modelling capability of the modeller. The auditor may belong to the water manager's organisation or to an independent organisation. The task of the auditor should be distinguished from internal reviews which the modeller's organisation often carry out as part of its internal quality assurance procedure. The reviews performed by the auditor are done over and above any internal reviews that the modeller may carry out. Background level Achtergrondwaarde The level of pollutants present in ambient air, water, soil or any other medium from natural sources. Also called Background concentration. Backwater gestuwd water Water backed up or retarded in its course as compared with its steady state, normal or natural conditions. Backwater curve stuwkromme Longitudinal profile of the water surface in a stream where the water surface is raised above its normal level by a natural or artificial obstruction. Balance Balans Comparing of masses of a specific substance or liquid, involved in the supply and drainage and changes in storage over a certain period and within a certain area. Bank oever Rising land bordering a river, lake or sea. Barrage stuw Barrier provided with a series of gates or other control mechanisms, across a stream to control the water-surface level upstream, to regulate the flowor to divert water supplies into a canal. (see also barrier;dam; weir) Barrier opwas Obstruction to the flow of surface water. (see also barrage; weir; dam) Base width (of a flood basisbreedte (van een Time interval between the beginning and the end of the direct runoff produced by a storm. hydrograph) hoogwater hydrograaf) Baseflow basisafvoer Part of the discharge which enters a stream channel mainly from groundwater, but also from lakes and glaciers during long periods when no precipitation or snowmelt occurs. Complementary to quickflow. Baseflow basisafvoer That portion of stream discharge derived from groundwater seepage into the stream. Baseflow inde basisafvoer inde Numerical inde quantifying the proportion of total flow that can be considered as baseflow. Baseline study baseline onderzoek An inventory of a natural community or environment to provide a measure of its condition at a moment in time - often done to describe the status of diversity and environmental condition against which future change can be gauged (usually development drive) Basin watershed; catchment; Hydrological Basin; Drainage basin basin response catchment response stroomgebied stroomgebied reactie An area of land, bounded by a divide, in which water flowing across the surface will drain into a stream or river and flow out of the area through a specified point on that stream or river Synonomous terms are catchment and watershed. Generally a basin is defined at a regional scale whereas a catchment or a watershed can be of smaller area. The term catchment is mostly used in Europe, while watershed is a preferred term in USA. Manner in which a basin reacts to a meteorological event or sequence of events. Basin, retarding opslag basin Basin which reduces peak flood flows of a stream through temporary storage. (see also flood-control reservoir) Benchmark hoogtemerk Relatively permanent mark, natural or artificial, having a point at a known elevation in relation to an adopted datum. Bend bocht Change in the direction of a stream. Benefit-Cost ratio baten-kosten ratio Is the ratio of the present value of all benefits to the present value of all costs. Benthic Benthisch Of, pertaining to, or living on or in the bottom of the water body; upon or attached to the bottom van 85

8 Naam Engels Afkorting Synoniem Begrip Description Bias systematische fout Systematic deviation between a measured (i.e., observed) or computed value and its true value. Bias is affected by faulty instrument calibration and other measurement errors, systematic errors during data collection, and sampling errors such as incomplete spatial randomization during the design of sampling programs Bifurcation splitsing Division of a stream into two branches. (see also fork) Bio available bio beschikbaar Generally refers to pollutants or contaminants which can be taken up by organisms, i.e., from water, sediment, suspended particles, food. Biochemical Oygen Demand BOD Biologisch zuurstofverbruik The amount of dissolved oygen required during the aerobic decomposition of organic matter in a body of water. Or, a measure of the quantity of oygen used in the biochemical oidation of carbonaceous and nitrogenous compounds in a specified time, at a sp Biocide verdelgingsmiddel A chemical preparation used for the control or eradication of a pest or a plant, including insecticides, herbicides, fungicides, and rodenticides. Biodegradable Biologisch afbreekbaar An organic material's capacity for decomposition as a result of attack by microorganisms. Sewage-treatment processes are based on this property. Biodegradable materials do not persist in nature. Bioenergetic Models bio energetische modellen A type of biological process model where optimal location and behaviour of an organism is based on energy budgets. Biota biota All of the organisms, including animals, plants, fungi, and micro-organisms, found in a given area. Biota domain Ecological domain Biotisch domein The biota (ecological) modelling domain comprises water quality processes in all surface water elements such as: - River systems including flood plain, lakes and reservoirs - Estuaries and coastal waters The biota (ecological) domain in HarmoniQuA corresponds to the ecological aspects in 'river' 'lake' 'transitional water' and 'coastal water' as these terms are defined in the Water Framework Directive. Biotic Biotisch Pertaining to any aspect of life, especially to characteristics of entire populations or ecosystems. Bore (well) geboorde bron A structure drilled or dug below the surface to obtain water from an aquifer system. Boundary conditions randvoorwaarden Conditions put to the (spatial) boundaries of a model in order to make the solution of a differential equation unambiguous. Brackish (water) Brak (water) Brackish refers to an area of low salinity where fresh water and sea water are mied near the estuary of a river flowing into the sea. In addition, tidal flats and lagoons of low salinity are also considered brackish areas. Brook beek Small, shallow stream usually in continuous flow in somewhat turbulent manner. (see also creek) Cableway kabelbaan Cable stretched above and across a stream, from which a current meter is suspended and moved from one bank to the other at predetermined depths below the water surface. Calibration, Initial Conditions aanvangs condities ijking The initial hydrologic conditions for a flow system that are represented by its aquifer head distribution at some particular time corresponding to the antecedent hydrologic conditions in that system. Initial conditions provide a starting point for transie Calibration, Steady State rust toestand ijking The calibraton of a model to a set of hydrologic conditions that represent (approimately) an equilibrium condition that does not account for changes in storage. Calibration, Transient or overgang of dynamische The calibration of a model to hydrologic conditions that vary dynamically with time, including changes in aquifer storage. Dynamic ijking Canal Kanaal Artificial open channel. Capacity Capaciteit Volume that can be contained by a reservoirs Capacity Capaciteit rate of flow that can be carried by any conveying structure. Capacity, in-bank capaciteit tussen de Discharge conveyed in the water course without overtopping the bank. oevers Capital ependitures kapitale uitgaven Ependitures where the good, such as a water project, purchased has an epected life of more than one year (capital good). Cauchy condition Boundary condition - Third Type voorwaarde van Cauchy A boundary condition for a groundwater model where the relationship between the head and the flow at a boundary is specified, and the model computes the groundwater flu for the head conditions applied. Also known as a Head- Dependent, mied or Third Type van 85

9 Naam Engels Afkorting Synoniem Begrip Description Boundary: Head Dependent Flow Channel kanaal natural, or artificial, clearly distinguished, waterway which periodically or continuously contains moving water, or which forms a connecting link between two bodies of water. Channel Vaargeul Deepest portion of a river bed, in which the main current flows Channel detention kanaalberging Volume of water which can be temporarily stored in channel during flood periods. (see also channel storage) Channel flow kanaalafvoer Flow of water in a natural or artificial channel (watercourse) with a free surface. Channel storage kanaalberging Volume of water stored in a channel. (see also channel detention) Channel, by-pass omleidingskanaal Channel built to divert flood flows from a point upstream of a protected region to a point downstream. Channel, stable stabiel kanaal Channel in which accretion balances scour on the average. Channel, unstable instabiel kanaal Channel in which stage-discharge relations change in the course of time. Chemical Oygen Demand COC; COD Chemical Oygen Chemisch zuurstofverbruik The amount of oygen required to oidize organic chemical compounds and oidizable inorganic compounds in a body of water. COD, an indicator of water contamination, is the amount of oygen consumed (mg/l) by potassium permanganate or other oidation agen Consumption Chezy formula Chezy formule Formula relating the mean velocity V of a stream to its hydraulics radius R, energy slope S and the cannel roughness epressed by the Chezy coefficient C: (see also coefficient of roughness) Chloride hydrocarbons Gechloreerde koolwaterstoffen A class of persistent, broad-spectrum insecticides, notably DDT, that lingers in the environment and accumulates in food chain. Other eamples are aldrin, dieldrin, heptachlor, chlordane, lindane, endrin, mire, benzene, heachloride, and toaphene. Chloride ion chloor ion Chloride ion refers to ionized chloride (Cl-), which forms ionized compounds with various metals. Chloride ion is also found in natural water, measuring several ppm in river water and 1.9% in sea water. Chlorinity Chloriniteit (Cl,?) The measure of chloride content of sea water by mass. Epressed in grams per kilogram or parts per thousand (ppt). Chlorophyll Chlorofyl A group of green pigments that makes it possible for plants to carry on photosynthesis. Chlorophyll?a is an indicator for algae/phytoplankton. Coastal waters Kustwateren As a management definition, territorial or interior waters that contain a measurable quantity or percentage of see-water (e.g., more than 0,5 parts per thousand). code Verification Verification code verificatie Substantiation that a model code is in some sense a true representation of a conceptual model within certain specified limits or ranges of application and corresponding ranges of accuracy. Coefficient of roughness ruwheids coefficient Coefficient epressing the influence of roughness of channel on the mean velocity in a stream cross section. Most commonly used coefficient of roughness are related to coefficient C in the Chezy formula through the following epressions, where R is the hydraulic radius, n is Manning`s coefficient (metric system): (see also Chezy formula) Coefficient, contraction samentrekkings coefficient in hydrometry, the ratio of the normal wetted cross-sectional area of the vena contracta to the nominal cross-sectional area of the orifice or weir opening. Coefficient, contraction samentrekkings coefficient Ratio between the decreased length, area of section, or volume and the original length area of section, or volume Coliform bacteria Coliform bacterie Coliform bacteria are present in the intestines of humans and animals in large numbers and also widely found in the outside environment contaminated by ecreta (e.g.: Ecoli). Bacteria tests are considered to eamine the presence of bacteria in foodstuffs van 85

10 Naam Engels Afkorting Synoniem Begrip Description Coliform count Coliform inde coliform telling Coliform count is used as a measure of water contamination, especially by human and animal ecreta. There are several bacteria that have similar characteristics to those of coliforms. Since daily routine tests cannot distinguish between these bacteria and Colloid colloïde Refers to particles of a size smaller than clay size. Colloidal particles are usually on the order of 10-7 to 10-5 cm in size. Colour Kleur Pure water is colourless, transparent and clear, but water acquires colour when it contains various dissolved substances. Colour is epressed as compared to a standard solution. Comparison to other models Model Vergelijking met andere The output of one model can be compared to that of another model. Comparison modellen Compensation depth, CaCO3 CaCO3 compensatie diepte The depth at which the amount of CaCO3 produced by the organisms in the overlying water column is equal to the amount of CaCO3 the water column can dissolve. There will be no CaCO3 deposition below this depth. Compensation depth, O2 O2 compensatie diepte The depth at which the oygen produced by photosynthesis is equal to the oygen requirements of plant respiration. A plant population cannot be sustained below this depth which will be greater in the open ocean than near the shore due to the relatively de Complete miing in a tank volledige menging in een tank It is the simplest form of miing behaviour to assume, requires no etra parameters to describe it, and seems to apply quite well to a large number of facilities that operate in fill-and-draw fashion. Conceptual Model Conceptueel model A description of reality in terms of verbal descriptions, equations, governing relationships or natural laws that purport to describe reality. This is the user's perception of the key hydrological and ecological processes in the study area and the corresponding simplifications and numerical accuracy limits that are assumed acceptable in order to achieve the purpose of the modelling. Confining layer afgesloten laag A body of material of low hydraulic conductivity that is stratigraphically adjacent to one or more aquifers. It may lie above or below the aquifer. Conjunctive use Gecombineerd gebruik The combined use of surface water and groundwater storage to optimise avaliable water resources. Constant Constante A quantity with a fied value (e.g. the speed of light or gravitational force) representing known physical, biological or ecological activities. Consumer surplus consumenten overschot The amount a household would pay for a good or service (e.g. water) minus the amount actually paid. This term is applied to measure the economic net benefit from using water. The consumer surplus can be derived from a demand function for water (inverse functional relationship). Contaminant vervuilende stof Any foreign substance present in another substance; e.g., in the case of water, a chemical or biological substance in a form that can be incorporated into, onto, or be ingested by and that harms aquatic organisms, consumers of aquatic organisms, or users Contamination vervuiling Introduction of any undesirable foreign substance -- physical, chemical or biological -- into an ecosystem. Does not imply an effect (see pollution). Usually refers to the introduction of human-produced substances. Continuity equation continuiteitsvergelijking Equation desribing the conservation of mass of flowing matter. Continuous model continu model A model that is run at each time step over a hydrological year. Control sections meetpunt section of an open conduit or stream where the discharge is uniquely determined by the water level immediately above it. Control valve afsluitmiddel It regulates the flow by closing or opening. It may be located and act as in-line (inside a pipeline), in-line at the end (in front of a lower reservoir) or as free-discharge valves with an outflow into the atmosphere. Cost-Effectiveness Kosten effectiviteit Assessment criteria for strategies to reach an objective by minimising the cost or to maimise the benefits by using a limited budget. Cost-recovery kostendekkende eploitatie The etent to which the costs of water services are covered by the payments of the water users. Appropriate water prices have to ensure at least a full cost-recovery. Costs of water services kosten van watergebruik Includes the costs of providing different water services, such as water abstraction and delivery, wastewater treatment and disposal, and flood control. They consist of capital cost, and operating and maintenance costs. Creek beek Natural stream of water, normally smaller than, and often tributary to, a river. (see also brook) Crest kruin Top of a dam, levee, spillway or weir to which water must rise before passing over the structure or peak stage of the flood wave (see also Flood crest) van 85

11 Naam Engels Afkorting Synoniem Begrip Description Crest gauge Crest gage topstand meter Device used to record the highest water stage. Critical depth Kritische diepte Depth of water flowing in an open channel under conditions of critical flow. Critical discharge Kritische afvoer Discharge that maintains critical flow on a given channel section for a fied depth of flow. Critical flow Kritische stroming Flow conditions at which the discharge is a maimum for a given specific energy, or at which the specific energy is minimum for a given discharge. Critical velocity kritische snelheid Velocity at critical flow in a channel Critical velocity kritische snelheid velocity at which flow changes from laminar to turbulent, or inversely. Cross section (of a stream) dwarsdoorsnede (van een Section of the stream at right angle to the main (average) direction of flow. stroom) Crossover overgang Relatively short and shallow length of a river between bends. Culvert duiker Closed conduit for the free passage of surface drainage water under a highway, railroad, canal or other structure. Cumulative precipitation gauge cumulatieve neerslagmeter Precipitation gauge used at stations, which are visited only at long-spaced time intervals. Current Stroom Flowing water (see also river; stream; watercourse) Current meter Stroommeter Instrument for measuring the velocity of water at a point by ascertaining the revolutions of buckets or propellers against which the current impinges. Cut-off Cutoff afsnijding Direct channel, either natural or artificial, connecting two points on a stream, thus shortening the length of the channel and increasing its slope. Cyanide Cyanide Cyanides are compounds of metals with hydrocyanic acid. Highly toic, cyanide ingested in a human body causes dyspnoea and death within several seconds; the lethal dose is estimated at 0.06 g. Cyanide is contained in waste water discharged from plating Dam Dam Barrier constructed across a valley for impounding wateror creating a reservoirs. (see also barrage; weir; barrier) Darcy's law Wet van Darcy An empirical equation developed to compute the quantity of water flowing through an aquifer. Usually epressed as Q=KiA or Q=Tiw, where Q= flow, K= hydraulic conductivity, i=hydraulic gradient, A=aquifer cross-sectional area, T=transmissivity, and w=width Data Assimilation Updating gegevensassimilatie Approach in which observed data are integrated in a model simulation in a way that the information content of both data and model result are made eplicit and weighted. Data assimilation is a feed back process where the model simulation is updated as a response to field observations. This is in certain domains denoted updating. Data bank Database Databank Comprehensive set of related data files for a specific application, usually on a direct access storage device. Data processing Data verwerking Handling of raw observational data until they are in a form ready to be used for a specific purpose. Data Uncertainty Parameter Uncertainty Data onzekerheid Uncertainty that is caused by measurement errors, analytical imprecision and limited sample sizes during collection and treatment of data. Data, historical Historische data Hydrological and meteorological data of events which occurred in the past. Datum level verticaal referentievlak Horizontal surface used as a reference to which elevations are related. Decomposers reducenten Primarily bacteria that break down nonliving organic material, etract some of the products of decomposition for their own needs, and make available the compounds needed for plants production. Bacteria that reduce dead matter to basic minerals. Degradable Afbreekbaar That can be reduced, broken down or chemically separated. Degree-day graad-dag Algebraic difference, epressed in degrees C, between the mean temperature of a given day and a reference temperature. For a given period (months, years) algebraic sum of the degree-days of the different days of the period. Demand vraag It allows to define the amount of baseline demand flow to be applied to the junction node Demand management vraagbeheersing Policies to change the quantity of water that users choose to consume. Demand Pattern vraagpatroon It allows to define the ID of the demand pattern to be applied to the junction node demand values during an etended period simulation Density Dichtheid The total weight or mass of any substance or material, per unit of volume? normally g/m3 or mg/l. Usually epressed as van 85

12 Naam Engels Afkorting Synoniem Begrip Description grams per cubic centimeter. E.g., for ocean water with a salinity of 35? at 0 C, the density is g/cm3. Depletion curve uitputtings curve Curve shoving a decreasing rate of runoff or discharge, caused by depletion. Depreciation Afschrijving An accounting device to write down the economic value of a capital good, such as a water project. Depression Storage berging in Rainfall retained in surface hollows which does not contribute to runoff. bodemoneffenheden Desalination Ontzilting Removing salt from ocean or brackish water. Design Ontwerp A project that involves modelling studies for design purposes. A design study is typically preceded by a planning study, and typically puts higher requirements to model performance than the preceding planning study. Design flood ontwerp peil Flood hydrograph or instantaneous peak discharge adopted for the design of a hydraulic structure or river control taking into account economic and hydrological factors. Design storm ontwerp storm Rainfall amount and distribution adopted over a given drainage area, used in determining the design flood. Design, optimal optimaal ontwerp System design based on the selection or combination of all pertinent variables so as to maimize some objective function (such as net benefits) with the requirements of the design criteria. Detailed Design Model gedetailleerd ontwerp This type of model is used for detailed investigations, scheme appraisals and for the detailed design of schemes. model Detergent reinigingsmiddel Detergent is mainly classified into soap, which has been in use since ancient times; and synthetic detergent, a product of modern chemical industry. Soap is made of higher fatty acid as its main ingredient, to which a builder is added to enhance cleansing Deterministic Model deterministisch model A model is said to be deterministic if it does not contain any random component, and its response due to a given input therefore is uniquely determined. The opposite to a deterministic model is a stochastic model. Detritus Detritus Particles of plant matter in varying stages of decomposition. Dioin Dioine Common name for any of a family of compounds chemically known as tetrachloro-dibenzo-p-dioins. Concern about them arises from their potential toicity and contaminants in commercial products. Tests on laboratory animals indicate that it is one of the mo Direchlet condition Boundary condition - First Type Boundary: Constant Head dirchlet voorwaarde A boundary condition for a groundwater model where the head is known and specified at the boundary of the flow field, and the model computes the associated groundwater flow. Also known as a Specified, Fied, Constant Head or First Type boundary condition. Direct runoff snelle afvoer That part of surface runoff which reaches the catchment outlet shortly after the rain starts. Its volume is equal to rainfall ecess. Some procedures for its derivation include prompt subsurface runoff but all eclude base flow. Discharge Afvoer The volume of water flowing in a stream or aquifer past a specific point in a given period of time. Discharge area afvoergebied An area where there are upward components of hydraulic head in the groundwater system resulting in the flow of water to springs, seeps or surface water bodies, or by evaporation and transpiration. Discharge, bankfull afvoer tussen de oevers Discharge corresponding to the bankfull stage. Discount rate discontopercentage The interest rate used to discount future benefits and costs of water projects. The rate reflects a value judgment based on compromise between the present consumption and capital formation from the viewpoint of the decision maker (a firm or public agency). A low discount rate is favorable to the construction of public works projects, such as in the water sector. Discretisation Discretisering Spatial distribution of a model area in model specific calculational units or temporal distribution of a simulation period in temporal steps. Disphotic zone Schemerzone The dimly lit zone corresponding approimately with the mesopelagic. Sometimes called the twilight zone. There is not enough light to carry on photosynthesis. Dissolved Oygen DO Opgeloste zuurstof Dissolved oygen (DO) refers to the amount of oygen dissolved in water. DO is essential for the self-purification process of water and aquatic organisms. Factors such as water temperature, air pressure and salt content affect DO. Highly contaminated wa Distributed model gedistribueerd model Model using spatial distribution of catchment characteritics and inputs according to a predefined grid van 85

13 Naam Engels Afkorting Synoniem Begrip Description Diversion of water omleiden van water Transfer of water from one water course to another, such water courses being either natural or artificial. Domain Domein In HarmoniQuA the description of the modelling process is decomposed into seven different domain: - groundwater (including solute transport and geochemistry) precipitation runoff (including non-point pollution) - hydrodynamics (flows in pipes, rivers, estuaries, coastal water and associated sediment transport and morphology) - flood forecasting - surface water quality - biota (ecology) - socio-economics Domain of Applicability (of Conceptual Model) toepassingsdomein (van een conceptueel model) Prescribed conditions in space, time and types of applications, for which the conceptual model has been tested, i.e. compared with reality to the etent possible and judged suitable for use (by model confirmation). Domain of Applicability (of Model Code) toepassingsdomein (van de model code) Prescribed conditions in space, time and types of applications, for which the model code has been tested, i.e. compared with analytical solutions, other model codes or similar to the etent possible and judged suitable for use (by code verification). Prescribed conditions in space, time and types of applications, for which the site-specific model has been tested, i.e. compared with reality to the etent possible and judged suitable for use (by model validation). Domain of Applicability (of Model) toepassingsdomein (van het model) Domestic waste water Huishoudelijk afvalwater Domestic waste water is waste water from the kitchen, laundry, bathroom, lavatory and toilet. Domestic waste water ecludes human waste. Double mass curve dubbele massa curve Plot of successive accumulated values of one variable against the contemporaneous accumulated values of another variable. Downstream stroomafwaarts In the direction of the current. Drain drain Conduit or small channel by which water is removed, from a soil or an aquifer by gravity, in order to control the water level. Drainage Area Planning Model bemalingsgebied planningsmodel This type of model is used to give an overview of a specific drainage area, which may be a discrete catchment in its own night or may be part of a larger catchment. Drawdown grondwaterstandsverlaging The lowering of the water table in an unconfined aquifer/aquitard or the potentiometric surface in a confined aquifer/aquitard due to pumping of groundwater from wells. Drawdown peilverlaging lowering of the water level in a reservoirs. Drawdown peilverlaging Curving downward of the water surface near the edge of an overfall or weir Drizzle motregen Very small water drops that precipitate at a rate usually less than 1 mm per hour. Drought Droogte A period of abnormally dry weather sufficiently prolonged for the lack of water to cause a serious hydrologic impact (i.e., crop damage, water supply shortage, etc.) in the affected area. Dry density Droge dichtheid The total weight of solids only per unit of volume. (also see: density) Dupuit assumptions aannames van Dupuit The following assumptions for flow in an unconfined aquifer: (a) the hydraulic gradient is equal to the slope of the water table, (b) streamlines are horizontal and (c) equipotential lines are vertical. Duration curve duurlijn Graph representing the time during which the value of a given parameter (e.g. water level, discharge) is equaled or eceeded regardless of continuity in time. Dynamic Equilibrium dynamisch evenwicht A condition in which the amount of recharge to a flow system equals the amount of natural discharge. Dynamic model Nonstationary Dynamisch model Model in which time is an independent variable. model; Transient model Dynamic Wave Method dynamische golf methode A more comple method of calculating flow which allows surcharge and backwater and reverse flows to be considered. It can therefore cope with looped systems. Ecohydraulics ecohydraulica The relationship between the hydraulics of water bodies, e.g. rivers lakes, estuaries, coastal and marine, and their biota and ecology. Ecohydrology Ecohydrologie The study of the fundamental interrelationships between hydrology and biota at the catchment scale van 85

14 Naam Engels Afkorting Synoniem Begrip Description Ecology Ecologie The branch of biology dealing with the relations of organisms to one another and to their environment. Economic benefit economische winst A monetary measure of welfare improvement from some change in quantity or quality of a good or service, such as water supply or watewater treatment. Economic optimisation economische optimalisatie Includes least cost strategies, maimisation of cost-effectiveness and cost-benefit relationships. It addresses e.g. allocation of water among various users, reaching environmental standards, pricing of water services, assigning water abstraction and wastewater disposal rights. Economics of scale schaalvoordeel Lower average total cost at higher output levels. Ecosystem Ecosysteem The organisms of a particular habitat, such as a pond or forest, together with the physical environment in which they live; a dynamic comple of plant, animal, fungal, and micro-organism communities and their associated non-living environment interacting Effective Porosity effectieve porositeit The amount of interconnected pore space throug which fluids can pass, epressed as a percent of bulk volume. Part of the total porosity will be occupied by static fluid being held to the mineral surface tension, so effective porosity will be less than tot Effective rainfall effectieve regenval In agriculture: that portion of the rainfall which remains in the soil and contributes to the growth of crops. Effluent Effluent Waste material discharged into the environment (e.g. a stream, a lake or an estuary), treated or untreated. The outflow of a sewer, industry pipe, or other waste discharge. Generally, refers to water pollution. Emergency spillway nood overlaat Auiliary spillway used in the event of floods eceeding the capacity of the main spillway. Emission Emissie Release of substances, usually from a point source. Emission factor Emissie factor The relationship between the amount of pollution produced and the amount of raw material processed. Emission limit emissie grens The same as Emission standard. The maimum amount of a pollutant that is permitted to be discharged from a single pollution source. Emitter emitter An element of the network. The device associated with junctions that model the flow through a nozzle or orifice Empirical Model Empiricallybased Empirisch model A model where the structure is derived, not from from knowledge on the physical, biological or ecological processes, but Model; from analyses of relationship among observed data. Black Bo Model Endothermic reaction Endothermische reactie A chemical reaction which absorbs energy. For eample, energy is stored in the organic products of the chemical reaction photosynthesis. Energy gradient Energy slope energie verhang Decrease or loss of the total head along a conduit (or channel) per unit conduit (or channel) length. (see also hydraulic gradient) Energy, specific Head, energy; Head, total specifieke energie Energy per unit weight of the fluid at an given location and time. In open cannel hydraulics it is the sum of the largest water depth and the average specific kinetic energy in a given cross section of a channel. Entropy Entropie Used in all applications of GENERAL SYSTEMS THEORY to describe the amount of free energy (sometimes construed as the amount of UNCERTAINTY) IN A SYSTEM. It is a negative quality in that maimum entropy relates to the minimum amount of free energy and, th Environment milieu The sum of all physical, chemical, and biological factors to which an organism or community is subjected. Environmental costs milieukosten Represent the economic value of damages that water uses imposes to the environment. Since non-market values play an important role, the application of special methodologies to evaluate the damages is necessary (such as the contingent valuation method). Environmental Impact Assessment EIA Milieu Effect Beoordeling Environmental impact assessment refers to a process involving the investigation, estimation and evaluation of the effect of a project or activity on the environment and is usually conducted by the proponent for the proposed undertaking in the process of p Environmental indicator milieu indicator Environmental indicator refers to a measure/ parameter for evaluating a given environmental state as quantitatively as possible. Environmental indicators are used for various purposes, including (1) assistance to devising plans and measures, (2) assistan Environmental quality standard milie kwaliteits standaard The requirements which must be adhered to by a given environment or part thereof (e.g. air, surface, water, ground van 85

15 Naam Engels Afkorting Synoniem Begrip Description water). Ephemeral stream Intermittent regenrivier Stream which flows only in direct response to precipitation or to the flow of an intermittent spring. stream Epifauna Epifauna Animals that live on the bottom, either attached or moving freely over it. Epilimnion Epilymnion The upper layer of a water body that suffers the influence of atmospheric temperature and sun light, located above the thermocline. It is the area of warmest water within the water body and normally the area of most activity. Epipelagic Epipelagisch The upper region of the oceanic province, etending to a depth of about 200 m. Equipotential Line Equipotentiaal lijn A line in a two-dimensional groundwater flow field such that the total hydraulic head is the same for all points along the line. Equipotential Surface Equipotentiaal vlak A surface in a three-dimensional groundwater flow field such that the total hydraulic head is the same everywhere on the surface. Estuaries estuarium Areas where freshwater meets saltwater (bays, mouths of rivers, salt marshes, lagoons). Those brackish water ecosystems shelter and feed marine life birds, and wildlife. Euphotic zone eufotische zone The surface layer of the ocean that receives enough light to support photosynthesis. The bottom of this zone which marks the compensation depth varies reaching a maimum value of around 150 m in the very nearest open ocean water. Euryhaline euryhalien Pertains to the ability of a marine organism to tolerate a wide range of salinity. Eurythermal eurythermisch Pertains to the ability of a marine organism to tolerate a wide range of temperature. Eutrophication Eutrofiering The process of over-fertilization of a body of water by nutrients producing more organic matter than the self-purification processes can overcome. In a body of water, where little echange of water occurs, the inflow of industrial, domestic and agricultu Evaporation Verdamping The physical process by which liquid is transformed into vapour. Evapotranspiration evapotranspiratie The combination of the processes of evaporation and transpiration. Eergy eergie The amount of work, the system can perform when brought into thermodynamic equilibrium with a well defined reference state (for instance the same system at thermodynamic equilibrium at the same temperature and pressure as the considered ecosystem). Eothermic reaction Eothermische reactie A chemical reaction that liberates energy. For eample, the energy stored in the products of photosynthesis is released by the chemical reaction respiration. Epert Elicitation epert onttrekking A process for obtaining epert beliefs about subjective quantities and probabilities. Typically, structured interviews and/or questionnaires are used to elicit the necessary knowledge. Epert elicitations may also include coaching techniques to help the epert conceptualize, visualize, and quantify the knowledge being sought Etreme Event Time Series etreme gebeurtenis This is a series of storms derived from a rainfall record. tijdserie Etreme-condition tests etreme omstandigheden The model structure and output should be plausible for etreme or unlikely combinations of factors in the system. test Faecal coliforms faecale coliforme bacterieen Bacteria common to the digestive tract of human beings - and other warm-blooded animals. They are present in and indicative of domestic sewage and a high risk of disease if not controlled or eradicated. This parameter is commonly used to indicate the pres Fall bodemval Sudden difference in elevation in the bed of a stream of sufficient etent to cause the entire stream of water passing over it to drop nearly vertically for some distance before it resumes its course Fall val drop of water level at a point of a stream during a certain time. Fall Verval difference of the water levels at two points on a stream Fall Verval difference of water levels at the two sides of a weir or other hydraulic control structure Falling limb daling Part of a hydrograph in which the discharge is decreasing from a peak. False Negative Type 2 Error fout negatief Also known as false acceptance decision errors. False negatives occur when the null hypothesis or baseline condition cannot be rejected based on the available sample data. The decision is made assuming the baseline condition is true when in reality it is false van 85

16 Naam Engels Afkorting Synoniem Begrip Description False Positive Type 1 Error fout positief Also known as false rejection decision errors. False positives occur when the null-hypothesis or baseline condition is incorrectly rejected based on the sample data. The decision is made assuming the alternate condition or hypothesis to be true when in reality it is false. Fauna Fauna A collective term for the animal species present in an ecosystem, at a particular area or time. Feeder Tank voedingstank It is a suitably sized vessel which is connected by a pipe with the main pipeline. Feeder Tanks provide protection against sub-atmospheric pressure and the stored water starts flowing into the main pipe when the local hydraulic gradeline falls below the water level in the tank. Fertilizer meststof Any substance containing a nitrogen compound or nitrogen compounds utilized on land to enhance growth of vegetation; it may include livestock manure, the residues from fish farms and sewage sludge. The miture used as fertilizer supplies one or more of th Field Veld Field of a scalar (e.g. pressure), vector (e.g. velocity), tensor (e.g. stress) is a domain in each point of which one can define the value of the scalar, vector, tensor etc. (e.g. pressure field, velocity field, etc.) Finite difference method eindige-differentiemethode Method to solve (partial) differential equations using structured grids, in which Taylor epansion series are used to approimate derivatives. Finite element method Eindige elementen methode Method to solve (partial) differential equations using unstructured grids, in which shape functions are used to approimate derivatives. First-In-First-Out (FIFO) Plug Flow First-in First-out propstroming There is no miing of water at all during its residence time in a tank. Water parcels move through the tank in a segregated fashion where the first parcel to enter is also the first to leave. Physically speaking, this model is most appropriate for baffled tanks that operate with simultaneous inflow and outflow. There are no additional parameters needed to describe this miing model. Fiscal Fiscaal Concerning the getting and spending of money by government. Fitness geschiktheid The degree to which an organism passes on its genes to succeeding generations. Fied Percentage Runoff Model vast percentage afstromings model This model, as the name suggests, is simply based on each surface type having a fied percentage runoff. For eample paved surfaces might be allocated an 80% runoff and roofs might be allocated a 90% runoff. It is difficult to know what percentages should be used and there is little advice currently available. Flash flood stortvloed Flood of short duration that rises and falls quite rapidly (within a few hours of the causative event) with a relatively high peak discharge. It is usually the result of intense rainfall over a relatively small area. Flash floods may also result from the sudden release of water impounded by ice jams or dam or levee failures. Flocculation Flocculatie Particles suspended in a body of water generally have a negative electric charge, repelling each other and avoiding contact and bonding. Flocculation is the process by which clay and colloidal particles are aggregated into small groups or masses called?f Flood hoogwater Rise, usually brief, in the water level in a stream to a peak from which the water level recedes at a slower rate Flood overstroming The condition that occurs when water overflows the natural or artificial confines of a river or accumulates by drainage into low-lying areas. Flood vloed relatively high flow as measured by stage height or discharge. Flood berm vloedberm Channel for flood waters confined by flood embankments or levees Flood channel vloedgeul Channel for flood water Flood channel vloedschaar enlarged stream channel occupied during periods of high water. Flood control Flood hoogwaterbeheersing Protection of land areas from overflow, or minimization of damage by flooding. protection Flood crest topstand Highest (peak) elevation of the water level during a flood in a channel. Flood estimation vloed schatting Determination of flood return periods. Flood flow hoogwaterafvoer Volume of water flowing across a section of a stream during a flood per unit time. Flood forecasting domain hoogwater voorspellings domein The flood forecasting modelling domain comprises all modelling activities related to operational, real-time forecasting of floods in rivers and coastal waters. The flood forecasting domain in HarmoniQuA is applicable to the 'river', 'transitional water' and 'coastal water' as these terms are defined in the Water Framework Directive van 85

17 Naam Engels Afkorting Synoniem Begrip Description Flood frequency hoogwater frequentie Number of times a flood above a given discharge or stage is likely to occur over a given number of years. See also Return period. Flood marks hoogwaterlijn Natural marks left on a structure or objects indicating the maimum stage of the flood. Flood plain Flow channel; Bottom land; overbank uiterwaard Adjoining nearly level land at the bottom of the valley of a stream flooded only when the streamflow eceeds the carrying capacity of the normal channel. Flood proofing hoogwaterbescherming Techniques for preventing flood damage to the structure and contents of building in a flood-hazard area. Flood routing vormverandering van hoogwatergolf Technique used to compute the movement and change of shape of a flood wave moving through a river reach or a reservoir. Flood warning hoogwaterwaarschuwing Advance notice that a flood may occur in the near future at a certain station or in in a certain river basin. Flood wave afvoergolf Rise in streamflow to a crest, and its subsequent recession, caused by a period of precipitation, snow melt, dam failure or hydroelectric plant releases. Flood, design ontwerp hoogwater Flood hydrograph or instantaneous peak discharge adopted for the design of a hydraulic structure or river control taking into account economic and hydrological factors. (see also flood, maimum probable) Flood, maimum possible maimaal mogelijk hoogwater Greatest flood to be epected, assuming complete coincidence of all factors that would produce heaviest rainfall and maimum runoff. Flood-control reservoir bekken voor hoogwaterbeheersing Reservoir used only for the temporary storage of flood water which is then released as rapidly as channel conditions downstream permit. (see also reservoir, detention; basin, retarding) Flood-control works werken voor hoogwaterbeheersing Levees, banks or other works along a stream, designed to confine it to a particular channel or direct it along planned floodways, or a flood-control reservoir. flooding inundation onderwater zetten controlled spreading of water for irrigation, etc. flooding inundation overstroming Overflowing by water of the normal confines of a stream or other body of water, or accumulation of water by drainage over areas which are not normally submerged Floodwall hoogwater keermuur Wall, usually built of reinforced concrete, to confine stream to prevent flooding. Floodway nevengeul Cannel constructed to carry flood water (in ecess of the quantity that can be carried safely in the stream. Sometimes called a flood relief channel or bypass channel. Flora Flora A collective term for the plant species present in an ecosystem, at a particular area or time. Flora Flora All of the plants found in a given area. Flow Control Valve FCV stroomregelklep It limits the flow through a valve to a specified amount. The program will produce a warning message if this flow cannot be maintained without having to add additional head at the valve. Flow duration curve stroomduurcurve Graph representing the time during which the value of a given parameter, e.g. water level, is equalled or eceeded, regardless of continuity in time. Flow Monitor Locations afvoermeet lokaties The choice of monitoring sites is similarly a two stage process. Initially general locations rather than specific manholes should be selected. The number of monitors used will depend on the purpose and type of the model and the level of confidence that can be placed in the accuracy of the input data. Flow velocity stroomsnelheid Vector indicating the speed (velocity) and direction of a moving liquid (e.g. water). Flow, accelerated versnelde afvoer In channel hydraulics, flow in which the velocity increases in the direction of flow. Flow, free surface vrije oppervlakte stroming Flow of water in which an interfaces eists between air and water. Flow, laminar laminaire stroming Flow of a fluid in which the viscous forces are predominant. In channel flow the fluid particles move approimately in definite, relatively smooth paths with no significant transverse miing. In channel flow it occurs at Reynolds number smaller than Flow, natural natuurlijke stroming Flow in a stream as it would occur under natural conditions. Flow, non-uniform niet-eenparige stroming Flow in which the velocity vector is not constant along every streamline van 85

18 Naam Engels Afkorting Synoniem Begrip Description Flow, open channel stroming met een vrije Flowing water having its surface eposed to the atmosphere. waterspiegel Flow, overland oppervlakte afvoer Flow of water over the ground before it enters a definite channel. Flow, regulated gereguleerde afvoer Flow in a stream that has been subjected to regulation by water control structures or diversions. Flow, retarded vertraagde afvoer Flow in which the velocity decreases with the time at a certain point, or in which the velocity decreases along a path-line. Flow, subcritical stromend water Flow at a velocity less than critical. Flow, supercritical schietend water Flow with a mean velocity greater than the critical velocity. Flow, turbulent turbulente stroming Flow with the turbulence. In channel flow, it occurs at Reynolds number larger than approimately Flow, uniform eenparige stroming Flow in which the velocity vector is constant along every streamline. Flow, unsteady Flow, nonsteady; niet stationaire stroming Flow in which the velocity changes in magnitude or direction with respect to time. Flow, nonstationary; Flow, nonpermanent Flow, varied niet-eenparige stroming Flow occurring in streams having a variable cross section or slope. Fluid line Material line stroomlijn Line in a moving fluid continuum consisting always of the same fluid particles. ligne Flume meetgoot Artificial water way used to carry water across depressions, or when the construction of a normal conveyance channel or conduit is impractical or uneconomical. Flushing rate doorspoeltijd The rate at which the water of an estuary is replaced (usually epressed as the time for one complete replacement). Flu volumestroom The volumetric flow rate per unit area through which flow occurs. See also Discharge. Ford Voorde Shallow place where a stream may be crossed by traffic. Forecast Voorspelling Definite statement or statistical estimate of the occurrence of a future event. Forecast, ensemble samengestelde voorspelling Set of forecast values calculated by model runs differing from each other only with perturbed initial conditions or climatic outliers of given frequency to account the uncertainty in the forecast. Forecasting error voorspellingsfout Difference between a forecast and the observed value. Fork Vork Place where two or more streams flow together to form a larger waterway. (see also bifurcations) Freshet was Flooding or overflowing of a stream caused by heavy rains or snowmelt. Friction losses wrijvings verlies Total energy losses in the flow of water due to friction between the water and the walls of the conduit, channel or porous medium in which it flows. Usually epressed in units of height. Froude number Froude getal Dimensionless number epressing the ratio of inertia forces to gravity forces. v = velocity of flow; g = acceleration of gravity; l = a characteristic length Fundamental aquatic ecology Fundamentele aquatische Focused on understanding observed phenomena. ecologie Fuzzy rule-based model Model gebaseerd op "fuzzy" regels A type of epert model. Allows the use of imprecise or fuzzy information. Often much more epert knowledge is available than quantitative data, fuzzy rule-based modelling provides a very useful way of using this knowledge. For eample in habitat modelli Gaseous Cavitation gasvormende cavitatie It occurs when there is either considerable free air suspended in the liquid or when the cavitation process is slow enough that the amount of air inside the vapour cavity is increased due to degassing from the liquid. Gauge datum Gage datum peilschaal referentievlak Elevation of the of a gauge referred to a certain datum level. Gauge zero Gage zero nulpunt peilschaal Elevation at which the gauge zero is set. Gauging site Gaging site waterstands meetpunt Location on a stream where measurements of a water level and discharge are regularly made. General Algebraic Modelling System. GAMS Algemeen algebraisch modelleer systeem It is a high-level modeling system for mathematical programming problems. It consists of a language compiler and a stable of integrated high-performance solvers. GAMS is tailored for comple, large scale modeling applications, and van 85

19 Naam Engels Afkorting Synoniem Begrip Description allows you to build large maintainable models that can be adapted quickly to new situations. General equlibrium analysis Algemene evenwichts analyse The analysis of the inter-relationships that eist between subsectors of the economy. It includes equilibrium optimisation procedures that address the wide range of hydrological-economic processes in river basins. General Purpose Valve GPV afsluiter voor algemeen gebruik It provides the capability to model devices and situations with unique head loss - flow relationships, such as reduced pressure backflow prevention valves, turbines, and well drawdown behaviour. The valve setting is the ID of a Head Loss Curve. Ghyben-Herzberg principle Ghyben-Herzberg principe An equation that relates the depth of a saline interface in a coastal aquifer to the height of the freshwater table. Gravity flow gravitatie stroming Flow of water in which the effect of gravity is predominant. Grid Grid To solve a model consisting of (partial) differential equations in order to apply it in a specific area, one needs a spatial schematisation (discretisation). This schematisation is called a grid (or, sometimes mesh, raster or network). A grid has to be se Gross domestic product Bruto Binnenlands produkt The total value of the goods and services produced by the residents of a country. Groundwater Grondwater The water present in interconnected pores located below the water table. Groundwater divide grondwaterscheiding The boundary between two adjacent groundwater basins. The divide is represented by a high in the water table surface. Groundwater domain Grondwater domein The groundwater modelling domain comprises modelling activities related to groundwater, i.e.: - Groundwater flow (heads and flows) - Solute transport (advection, diffusion and hydrodynamic dispersion) - Geochemistry (ad/absorption, ion echange, compleation, degradation, etc.) The groundwater domain in HarmoniQuA corresponds to the term 'groundwater' as this term is defined in the Water Framework Directive. Groundwater flow model grondwaterstromingsmodel The application of a mathematical model to represent a site-specific groundwater flow system. Gutter Goot Shallow waterway provided at the margin of a highway for surface drainage. Habitat standplaats The environment in which an organism lives. Habitat can also refer to the environment in a particular place. In modelling studies, habitat is often qualified by its quality and quantity of its physical attributes. Habitat availability standplaats The habitat available to be used (i.e. the total environment) by an organism or community in a particular time and place. beschikbaarheid Habitat preference standplaats voorkeur A way of trying to estimate habitat quality by taking into account both habitat use and habitat availability. Habitat quality / suitability standplaats kwaliteit / toepasselijkheid The ability of available habitat to provide conditions that benefit an organism such as fitness, survival, ability to grow or reproduce. Habitat use / utilisation standplaats gebruik The habitat used by an organism or community in a particular time and place. Halocline Halocline A layer of water in which a high rate of change in salinity in the vertical dimension is present Hard water Hard water Alkaline water containing dissolved mineral salts that interfere with some industrial processes and prevent soap from lathering. Hardness Hardheid The hardness of water is indicated by the content of dissolved calcium and magnesium salts. Calcium and magnesium salts that are transformed to insoluble salts by boiling denote temporary hardness, while calcium and magnesium salts that do not settle whe Hazardous substances Gevaarlijke stoffen Substances which have adverse impacts on living organisms, e.g. toic, carcinogenic, mutagenic, teratogenic, harmful for the environment. head loss loss energy druk verlies Decrease of total head, epressed of height, due to energy dissipation. Headwaters bovenloop Streams from the sources of a river. Headworks costs kosten van The costs of abstraction, storage and treatment. reguleringswerk Heavy metals Zware metalen Metallic elements of large atomic weight (e.g. mercury, lead, nickel, zinc, copper and cadmium) that are of environmental concern because they do not degrade over time -- many are essential to life but can be toic at certain concentrations. At low concen Heterogeneous Heterogeen The condition under which one or more hydraulic properties of the groundwater flow system vary spatially van 85

20 Naam Engels Afkorting Synoniem Begrip Description Holistic modelling approach holistische modelleer benadering Hydrological and socio-economic model components are tightly connected within a consistent model. Especially the hydrological component is often considerably simplified due to model-solving compleities. Information transfer is conducted endogenously. However, modelling of large-scale river basins with different water domains requires usually a modular approach. Homogeneous Homogeen The condition under which the hydraulic properties of the groundwater flow system are independent of the position within the geological formation. Household demand function huishoudelijke vraagfunctie Relates the water demand of households to price of water and other factors, such as prices of other goods and services, family income and climate. Hydraulic conductance hydraulische geleiding A term that incorporates model geometry and hydraulic conductivity into a single value for simplification purposes. It controls the flow rate to or from a given model cell, river reach, etc. Hydraulic conductivity hydraulische geleidbaarheid A coefficient of proportionality that describes the rate at which water can move through a permeable medium. It is dependent upon properties of both the fluid (viscosity and density) and the medium. Hydraulic diffusivity hyraulische diffusiviteit A property of an aquifer or confining layer defined as the ration of the transmissivity to the storativity or alternatively as the ratio of the hydraulic conductivity to the specific storage. Hydraulic gradient hydraulische gradient The change in total head with a change in distance in a given direction. The direction is that which yields a maimum rate of decrease in head. See also Energy gradient. Hydraulic jump hydraulische sprong Sudden passage of water in an open channel from sub-critical depth to super-critical depth, accompanied by energy dissipation. Hydraulic Model Hydraulisch model Model describing the properties of fluid flow (e.g. depth, velocity, pressure, shear stress) in space and time. Hydraulic Model Hydraulisch model A model based on theoretical rules governing the behaviour of fluid. Hydraulic radius Hydraulische straal In a single cross section, the wetted area of the cross section of a stream or conduit divided by its wetted perimeter. Hydraulic structures kunstwerken Technical installations by means of which measures are taken in water management for the utilization of water resources and protective measures taken against harmfull effects of water. Hydraulic Time Step hydraulische tijdstap It specifies how often a new hydraulic computation of the network system is to be computed. Hydraulics Hydraulica Branch of fluid mechanics dealing with the flow of water (or other liquids) in conduits and open channels. Hydrocarbons Koolwaterstoffen Compounds found in fossil fuels that contain carbon and hydrogen and may be carcinogenic. Hydrodynamic domain Hydrodynamisch domein The hydrodynamic modelling domain comprises flows of water, sediment transport and morphological aspects in all surface water elements such as: - Water supply systems - Sewer drainage systems - River systems including flood plain, lakes and reservoirs - Estuaries and coastal waters The hydrodynamic domain in HarmoniQuA corresponds to the water flow and sediment aspects in 'river' 'lake' 'transitional water' and 'coastal water' as these terms are defined in the Water Framework Directive. Hydro-ecology Hydro-ecologie Used in a narrower sense (than ecohydrology) to describe the study of the interaction between ecological and hydrological/hydraulic processes in rivers and floodplains. Hydrograph hydrogram A graph that shows some property of groundwater or surface water as a function of time. Hydrograph, unit Unit Hydrograph eenheidshydrogram Discharge hydrograph of direct runoff resulting from a unit amount of runoff or effective rainfall generated uniformly over a catchment during a specified duration. Hydrographical network Hydrografisch netwerk Aggregate of rivers and other permanent or temporary watercourses, and also lakes and reservoirs, over any given area. Hydrography Hydrografie in particular, charting the open bodies of water for navigational purposes. Hydrological cycle Hydrologische cyclus The transport and transformation of gaseous, liquid and solid water in the earth-atmosphere system. Hydrological regime Hydrologisch regime Variations in the state and characteristics of a water body which are regularly repeated in time and space and which go through phases, e.g. seasonal. Hydrological year Hydrologisch jaar Continuous 12-month period selected in such a way that overall changes in storage are minimal so that carryover is reduced to a minimum van 85