Glossary T - Z


Refers to willingness to live with a risk to secure certain benefits and in the confidence that it is being properly controlled. To tolerate a risk means that we do not regard it as negligible, or something we might ignore, but rather as something we need to keep under review, and reduce still further if and as we can. Tolerability does not mean acceptability.

Source: FloodSite


A general concept that reflects our lack of sureness about someone or something, ranging from just short of complete sureness to an almost complete lack of conviction about an outcome.

Source: FloodSite


is the process of comparing model output with observations of the ’real world’.

Source: FloodSite


The change over time of the value or state of some parameter or system or element, where this change may be systemic, cyclical or exhibit no apparent pattern.

Source: FloodSite


A quantity, which can be measured, predicted or forecast which is relevant to describing the state of the flooding system e.g. water level, discharge, velocity, wave height, distance, or time. A prediction or forecast of a variable will often rely on a simulation model, which incorporates a set of parameters.

Source: FloodSite


The degree to which an individual understands and knowingly accepts the risk to, which they are exposed in return for experiencing a perceived benefit. For an individual may preferentially choose to live in the flood plain to experience its beauty and tranquillity.

Source: FloodSite


Vulnerability refers to the weakness of the system or element related to a certain threat. Vulnerability is a relative size i.e. it describes the degree to which a community or an element is either susceptible or resilient to impact of a damaging phenomenon. In this meaning it evaluates the extent of possible damage in a given area.

Source: TUHH

The conditions determined by physical, social, economic, and environmental factors or processes, which increase the susceptibility of a community to the impact of hazards.

Source: FloodSite (2005)

The potential for a receptor to be harmed.

Source: ISDR (2004)

Inherent characteristics of a system that create the potential for harm but are independent of the probability of any particular hazard or extreme event.

Source: ITC (2004)

Susceptibility * value

Source: Sarewitz et al (2003)

Refers to the resilience of a particular group, people, property and the environment, and their ability to respond to a hazardous condition. For example, elderly people may be less able to evacuate in the event of a rapid flood than young people.

Klijn (2004)

The amount of potential damage caused to a system by a particular-related event or hazard.

Source: HR Wallingford (2002)

The degree to which a system is susceptible to, or unable to cope with, adverse effects of climate change, including climate vulnerability and extremes. Vulnerability is a function of the character, magnitude, and rate of climate variation to which a system is exposed, its sensitivity, and its adaptive capacity.

Source: Jones and Boer (2003)

Characteristic of a system that describes its potential to be harmed. This can be considered as a combination of susceptibility and value.

Source: IPCC (2001) Climate change 2001: Impacts, Adaptation and Vulnerability, Summary for Policymakers, WMO

Water Butts

Storage of rain water for outside use.

Source: FLOWS, Cambridgeshire County Council (2006)

Water management

Water management refers to various activities, which aims for an optimal use and distribution of surface and subsurface water, the rationing of drinking water abstraction and distribution and an effective wastewater treatment. Besides the study, planning, monitoring, and application of quantitative and qualitative control and development techniques for long-term and multiple use of the diverse forms of water resources, also the flood protection counts to the tasks of water management.

Source: TUHH


Sealing of walls and ceiling to avoid water penetration into the structure. will be equalled or exceeded

  • Wet flood proofing

  • Dry flood proofing

Source: UNESCO/WMO Gloss. Hydrology (1992)


A weir is a small overflow-type dam commonly used to raise the level of a small river or stream.

Adjustable weir:

weir of which crest-height is adjustable. Crest can be lowered to increase water flow to low-lying area and to create space in the upstream area for rainfall capture. Crest can be raised to reduce (peak) discharge to low-lying area and store water in upstream area.

Source: FLOWS-Team, Waterboard Zuiderzeeland  (2006)


Wetproofing is a retrofitting strategy where the building is modified in a way that in case of flooding, the damage is minimised.

Source: TUHH

Zoning plans

are plans of restricted areas within the municipality.

Source: Nebert, D., ed. (2001): Developing Spatial Data Infrastructures: The SDI Cookbook

Headers and keywords
Page content





   G - I

   J - M

   N - Q



   T - Z >







Further Information