Glossary of Terms

Accretion

The addition of newly deposited sediment vertically and/or horizontally.

Adaptive capacity

The ability of a (human) system to adjust to (in this case) climate change (including climate variability and extremes), to moderate potential damages, to take advantage of opportunities, or to cope with the consequences.

Anthropogenic

Impacts that originate from humans.

Astronomical tide

Alteration in sea water level due to the gravitational forces of the sun and moon, creating tidal cycles, without any atmospheric influences.

Beach

A deposit of non-cohesive material (e.g., sand, gravel) situated at the interface between dry land and the sea (or other large expanse of water) and actively ‘worked’ by present-day hydrodynamic processes (i.e., waves, tides and currents) and sometimes by winds.

Climate change

Climate change refers to a change in the state of the climate that can be identified (e.g., by using statistical tests) by changes or trends in the mean and/or the variability of its properties, and that persists for an extended period, typically decades to centuries. Climate change includes natural internal climate processes or external climate forces, such as variations in solar cycles, volcanic eruptions and persistent anthropogenic changes in the composition of the atmosphere or in land use (MfE, 2017).

Coastal compartments

A length of coastline defined for the purpose of assessing interactions to examine and develop management scenarios. Developed in response to what the coast is telling us and based on coastal processes – coastal form and function – not necessarily administrative boundaries. Referred to as ‘Coastal Cells’ in TCDC’s Coastal Hazards Policy 2018.

Coastal environment

The TCDC Proposed District Plan (under development since 2012) includes a Coastal Environment Line, developed in consultation with the local community. This supersedes the maps included in the Waikato RPS.

Coastal flooding (inundation) 

Coastal flooding occurs in areas that lie on the coast of a sea, ocean, or other large body of open water. It is typically the result of extreme tidal conditions caused by severe weather. Storm surge - produced when high winds from hurricanes and other storms push water onshore - is the leading cause of coastal flooding.

Coastal hazards

Physical processes that expose a coastal area to the risk of loss of life, the degradation of environmental and cultural assets, and/or property damage. They are a subset of natural hazards covering tidal or coastal storm inundation, rising sea level, tsunami or meteorological tsunami inundation, coastal erosion (shorelines or cliffs), rise in groundwater levels from storm tides and SLR (plus associated liquefaction), and salinisation of surface fresh waters and groundwater aquifers. Herein, taken to be – in short – coastal inundation and coastal erosion, incorporating SLR and storm events.

Coastal inundation 

See coastal flooding 

CMA

The CMA includes the foreshore, seabed, coastal water and the air above the water – of which (a) the seaward boundary is the outer limit of the territorial sea; (b) the landward boundary is the line of MHWS, except where that line crosses a river, the landward boundary at that point shall be whichever is the lesser of (i) one kilometre upstream from the mouth of the river; or (ii) the point upstream that is calculated by multiplying the width of the river mouth by five.

Coastal protection

Relates to engineering works to mitigate the threat of erosion; can also relate to wave overtopping or flooding.

Crest

Highest point on a beach face, bedform or wave.

Datum

Any position or element in relation to which others are determined (i.e., heights).

Ecosystem

The combined physical and biological components of an environment. An area within the natural environment in which physical (abiotic) factors of the environment, such as rocks and soil, function together along with interdependent (biotic) organisms, such as plants and animals, within the same habitat.

Environment

Defined in the RMA 1991 as including: (a) ecosystems and their constituent parts, including people and communities; (b) all natural and physical resources; (c) amenity values; and (d) the social, economic, aesthetic, and cultural conditions which affect the matters stated in paragraphs (a) to (c) or which are affected by those matters.

Erosion

Wearing away of the land or sea by natural forces (e.g., wind, waves, currents and physical, chemical or biological weathering).

Estuary

The seaward part of a drowned valley system, subject to tidal fluctuations and the meeting and mixing of fresh river water with saltwater from the sea, receiving sediments from its catchment and from marine sources.

Fluvial flooding

Fluvial, or river, flooding occurs when excessive rainfall over an extended period of time causes a river to exceed its capacity. There are two main types of river flooding: ‘overbank’ flooding that occurs when water flows over the edges of a river or stream; and ‘flash flooding’, characterized by an intense, high velocity torrent of water that occurs in an existing river channel with little to no notice.

Foreshore

As defined in Section 2 of the RMA 1991, any land covered and uncovered by the flow and ebb of the tide at mean spring tides and, in relation to any such land that forms part of the bed of a river, does not include any area that is not part of the CMA.

Geomorphology/ morphology

The branch of physical geography/geology which deals with the form of the Earth, the general configuration of its surface, the distribution of the land, water, etc.

Gravel

Loose, rounded fragments of rock larger than sand but smaller than cobbles. Material larger than 2mm (as classified by the Wentworth scale used in sedimentology).

Hydrodynamic

The flow and motion of water produced by applied forces.

Kaitiaki

Trustee, minder, guard, custodian, guardian, caregiver, keeper, steward.

Kaitiakitanga

Practicing, undertaking the role of guardianship.

Longshore drift

The movement of sediment approximately parallel to the shore, primary driven by waves approaching the coast at oblique angles.

MHWS

The average of all high-tide water levels observed over a sufficiently long period and the line that marks the landward boundary of the CMA (MfE, 2017).

Natural asset / coastal asset

Natural coast protection assets include beaches and sand dunes, saltmarsh and mudflats, and mangroves.

Natural hazard

Any atmospheric, earth or water-related occurrence (including earthquake, tsunami, erosion, volcanic activity, landslip, subsidence, sedimentation, wind, drought, fire or flooding), the action of which adversely affects or may adversely affect human life, property, social and economic activities or other aspects of the environment (RMA 1991, Section 2). Hazards can be single, sequential or combined in their origin and effects. Each hazard is characterised by its timing, location and scale, intensity and probability.

Pluvial flooding

A pluvial, or surface water, flood is caused when heavy rainfall creates a flood event independent of an overflowing water body. Pluvial flooding can occur in areas that lie above coastal and river floodplains. There are two common types of pluvial flooding: (a) intense rain saturates an urban drainage system and the system becomes overwhelmed; or (b) run-off or flowing water from rain falling on hillsides that are unable to absorb the water.

Pluvial flooding often occurs in combination with coastal and fluvial flooding and, although typically only a few centimetres deep, can cause significant property damage.

Sand

Sediment particles with a diameter of between 0.063 mm and 2 mm. Sand is generally classified as fine, medium or coarse.

Sediment

Particulate matter derived from rock, minerals or bioclastic matter.

Sediment transport

The movement of a mass of sedimentary material by the forces of currents and waves.

SMP

Shoreline Management Plan: a non-statutory plan, which provides a large-scale assessment of the risks associated with coastal processes and presents a policy framework to reduce these risks to people and the developed, historic and natural environment in a sustainable manner. The MfE guidance (MfE, 2017) refers to Adaptive Planning Strategies, with supporting Implementation Plans.

Spit

Narrow accumulation of sand or gravel generally lying parallel to the coast with one end attached to the land and the other projecting seawards, often formed across the mouth of an estuary or bay.

Spring tide

A tide that occurs when the tide-generating forces of the sun and moon are acting in the same directions, so the tidal range is higher than average.

Stop banks

Defences for coastal inundation.

Storm surge

A rise of sea elevation caused by water piling up against a coast under the force of strong onshore winds and/or reduced atmospheric pressure.

Storm tide

The coastal water level (tide) produced by the combination of astronomical and meteorological (storm surge) ocean water levels.

Tāonga

Treasure - property, goods, effects that are prized

Tiakitanga

Good guardian- or stewardship.

Tidal range

The difference in height between successive high water and low water levels at a point.

Tide

The periodic rise and fall in the level of the water in oceans and seas. The result of gravitational attraction of the Sun and Moon.

Topography

Configuration of a surface including its relief and the position of its natural and man-made features.

Urupā

Burial ground, cemetery, graveyard.