Physical uptake of water and/or ions by a substance, the fluid entering the body from outside and becoming mixed with it.

Molecular attraction between two substances causing their surfaces to remain in contact ; water adhere to soil particles.

Attachment by simple attraction of a particle, ion or molecule to a surface; clay and humus are the main soil substances capable of adsorption.  

(a) A cluster of more or less fine earth or sand particles cemented together, for example, by colloids.

(b) Hard materials such as sand, gravel or stone used for mixing with a cementing material to form mortar or concrete.  

Sighting ruler used together with a plane-table.

Vertical distance or height above the mean sea level which is in this case the horizontal reference plane; see also "elevation". 

A class of organic compounds containing nitrogen, carbon, hydrogen and oxygen; large numbers become linked together to become proteins; some of them are essential for fish production.

Assemblage of aquatic organisms that are attached to, or move on, a submersed substrate but which do not penetrate into it.   

Horizontal angle formed by the magnetic north and a straight line or a direction; always measured clockwise from the magnetic north to the line/direction. 

(a) Measurement of the height above ground of a point of known elevation, for example in direct levelling; in this case, also known as a plus sight.

(b) Direction of a line measured when looking back to a previous survey point from a new point, whose direction has been defined as a foresight from the previous survey point; commonly used in traversing.  

Very small, one-cell organisms, often developing into large colonies and unable to produce carbon compounds through photosynthesis; primarily responsible for decay/decomposition of dead plant and animal matter.

A fine-grained black rock formed by the cooling of molten magma-igneous rock ; it disintegrates slowly to give dark soils which are clayey, rich in iron and calcium.

Permanent, well-defined ground point of known or assumed elevation used for example as the starting point of a topographical survey or as a reference point during constructions. A temporary bench-mark is used for a short period of time only, and is not permanently marked as a reference point.

Acid salts of carbonic acid (see carbonates); their solution in water contains the ion HC0₃ such as calcium bicarbonate Ca (HC0₃)₂ 

Stock of fish to be used for propagation, preferably under special management in separate ponds.

Organic compounds made of carbon, hydrogen and oxygen, such as sugars, starch and cellulose; usually the cheapest dietary source of energy, particularly for omnivorous and herbivorous fish.

Salts of carbonic acid, a compound formed from carbon dioxide (C0₂) in contact with water ; for example calcium carbonate, CaC0₃

Organic compound that constitutes the essential part of the solid framework of plants; also found in the animal body.

(a) Longitudinal axis of a canal or a dike.
(b) On a plan, a line drawn along the centre of a particular structure, dividing it into two equal-sized parts.  

A slowly permeable horizon or a heavy clay layer, found in flat areas or in shallow depressions where water stagnation occurs during the rainy season.

The force by which the particles hold together.

A soil particle of very small size (from 0.5 to 1 micron), either mineral (for example, colloid clay) or organic (for example, humus).

Rearrangement of the particles of a soil under the effect of a pressure, the small particles lodging themselves into the spaces left between the larger ones.

Imaginary line which joins all ground points of an equal elevation above a given reference plane.

Difference in elevation between two adjacent contours.

A drawn line which joins points of equal elevation on a plan or a map; it represents a contour as it is found in the field.

(b) When boring to obtain soil samples : the sampling core is the orderly assemblage of successive boring samples.

A view of a structure obtained by making an imaginary slice through it at a specified location; used in drawings to define the shape or method of construction of a structure.

Total distance from the starting point of a survey line.

Area where it is needed to lower the land to a required elevation by digging soil away

The process by which organic compounds decay, disintegrate or rot into simpler chemical compounds or elements.

Ratio of the weight of a certain volume of a material to the weight of the same volume of pure water

Any disintegrated organic matter accumulated in water, on mud or on soil. 

Vertical distance or height above a given "horizontal" reference plane; see also altitude.

Wear or scouring caused by the abrasive action of moving water or wind.

Increase of the earth volume when disturbed or excavated (syn.: bulking).

Area where it is needed to raise the land to a required elevation by bringing soil in.

Portion of the soil made of particles less than 2 mm in diameter.

A specially designed and shaped channel, used for conveying water by gravity; normally brick or concrete lined, for fast flowing water.

Pathways through which nutrients added to a pond are converted into fish flesh.

(a) Measurement of the height above ground of a point of unknown elevation, for example in direct levelling; in this case, also known as a minus sight.

(b) Direction of a line measured ahead (forward), from the line's initial point, for example in traversing.

Upper part of a canal, dike, or similar structure, between the water level and the top of the structure; ideally, it should never be under water.

Group of plants lacking the ability to produce carbon compounds/organic matter through photosynthesis; includes yeast and moulds. 

Rock similar to granite, but in which the minerals are disposed in beds; it results from the transformation of pre-existing rocks (metamorphic rock).

Hormones secreted by the pituitary gland, which stimulate the fish gonads and regulate their reproductive activity; also known as gonadotropic hormones.

Rock formed by the cooling of molten magma - igneous rock - containing about 65 percent feldspars, 25 percent quartz and other minerals, often mica; high in silica which may result in the formation of acid soils.  

Attractive force by which all bodies (including water) tend to move toward the centre of the earth, for example when moving or falling from a higher to a lower elevation.

A drawn representation of the ground surface which shows change in elevation (along the vertical axis) with distance (along the horizontal axis). 

Usually a very dense mineral soil of clay, sand and gravel that has been cemented together to form a rock-like layer; it will not soften when wet.

(a) The level at which water is held or can rise to, allowing it to flow to lower levels, push through pipes, etc.

(b) Pumping head : the level to which a pump can push water.
 

The loss of head, such as that occurring through friction or change of speed, as water is pushed through a pipe or other hydraulic structure.

Height above ground of the line of sight of a levelling instrument.

Line or plane, parallel to the plane of the horizon and at right angles to the vertical plane; flat, level.

Chemical substance produced in one part of an organism and usually transported in the blood to another part where it causes a specific effect; see for ex. gonadotropins.

Broken down organic material in organic fertilizers, composts or soils, in which most nutrients are available for fertilizing purposes.

Slope of the water surface within a wet earthen dike (see saturation line).

See Pituitary gland. 

Migration of soluble substances or of colloids in the interstices of the soil.

Operation of measuring differences in elevation at several ground points through a topographical survey.

Ground point where a levelling instrument is set up for a topographical survey.

Natural rock consisting chiefly of calcium carbonate CaC0₃

Imaginary line which begins at the eye of the surveyor and runs towards a fixed point; it is always a straight line, the "sighting line".

One of a large group of organic compounds (fats or fatlike) occurring widely in living organisms; dietary lipids have two main functions: as a source of energy and as a source of some essential dietary components (fatty acids) for growth and survival. 

Direction in which any point lies from a point of reference as measured from the magnetic north with a compass.

Direction in which the magnetized end of a compass needle points towards the north magnetic pole of the earth. Note: the position of the north magnetic pole is affected by local variations and corrections may be required for detailed use.

Rock resulting from the transformation of pre-existing rocks - metamorphic rock - formed chiefly of mica, disposed in beds; usually gives soils which are poor in calcium.

An elevation which is always subtracted; see foresight, definition (a).

One of the clay minerals, characterized by a very high cation-exchange capacity which results, for example, in a considerable shrink-swell potential.
 

In a soil profile, spot or blotch of different colours or shades of colour, interspersed with the dominant colour.

Loose covering made of organic residues (e.g. cut grass, straw, tree leaves) applied on the surface of the soil, mainly to conserve moisture and to check weed growth.

Assemblage of actively free-swimming animals in a pond; capable of sustained and directed mobility, such as insects and fishes.

Chemical reaction by which, for example, oxygen is added.

A line or plane equally distant at every point from another line or plane.

Land vegetation which grows and survives through more than one year and which is usually in leaf throughout the year.

A line or plane having a direction at right angles to a given line or plane.

(a) Process by which green plants containing chlorophyll convert light energy into chemical energy, producing organic matter from minerals. 

(b) Especially, production of carbon compounds from carbon dioxide and water, with the release of oxygen.
 

Small gland attached to the base of the fish brain, which produces a number of important hormones, such as gonadotropins.

An imaginary flat surface; every straight line joining any two points in it lies totally in it.

The various very small organisms, either plants (see phytoplankton) or animals (see zooplankton), which live suspended in the water.

Capacity of the soil to be deformed without breaking and to remain deformed even when the deforming force is removed.

Firm, iron-rich clay material that commonly occurs as red soil mottles ; it changes irreversibly to ironstone hardpans or irregular aggregates on exposure to repeated wetting and drying.
 

An elevation which is always added, see backsight, definition (a).

Fixed point, usually identified in the field by a marker at the end of a line of sight.

Cutting back the crown of a tree with the object of producing a close head of shoots (a pollard) beyond the reach of browsing animals, for commercial purposes or for amenity.

A geometrical figure or an area of land having more than three straight sides.

A discrete volume of soil atmosphere, completely surrounded by soil; may be filled with water.

The continuous and interconnecting spaces in soils.

Organic compound of large molecular size and complex structure, made up of one or more chains of amino-acids; fundamental to the structure and function of living organisms; dietary protein is essential for all animals, acting either as a tissue builder or as an energy source.

Very small single-cell animal organisms, sometimes living in colonies.

A four-sided polygon with four right angles.

Vertical distance to a common reference plane, such as the mean sea level (see "altitude") or an assumed horizontal plane (see "elevation"); it is calculated from survey data.

Elevation or plane which is repeatedly used during a particular survey, and to which survey points or lines are referred.

Process by which a living organism, plant or animal, combines oxygen with organic matter, releasing energy, carbon dioxide C0₂ and other products.

Thick, horizontal plant stem usually under ground, sending out shoots above and roots below.

A 90-degree angle.

A triangle with one 90-degree angle.

Upper limit of the wet zone within an earthen dike when partly under water.

Relationship existing between the distance shown on a drawing and the actual distance across the ground.

Downward movement of the soil within a fill such as a dike, because of natural factors (for ex. rain and weight of above soil) and artificial factors (for ex. compaction and weight of a vehicle).

A screen with square meshes, used primarily for sorting by size particles more than 0.05 mm in diameter; various series of standard sieves exist such as AFNOR (France), BSI (UK), DIN (Germany) and Tyler (USA).

Synonym for "line of sight". 

Flat, usually horizontal, molded layer of plain or reinforced concrete, usually of uniform thickness.

A lime putty obtained by adding water to quicklime.

Creeping plant stem or runner capable of developing roots and stem to ultimately form a new individual plant.

Increase of soil volume, such as for ex. the swelling of a clayey soil under wet conditions.

Mathematical function for angles.

A board frame used as a guide in bringing a canal, a dike, etc. to the desired shape.

(A) Base of a dike, away from the dike material.
(b) Inside toe: inside the pond; outside toe: outside the pond.

A four-sided polygon with two parallel sides.

A set of straight lines connecting established points around or along the route of a plan survey.

A three-sided geometrical figure or land area.

Temporary intermediate or reference point being surveyed between two established points; it is no longer needed after the necessary reading has been taken.

Line or plane which is perpendicular to a horizontal line or plane; in practice, defined by a plumb line.

Complex organic compound required by animals in very small amounts for growth, reproduction, health and general metabolism.

The condition of being thoroughly soaked with water.

Members of the zooplankton community.

Very small aquatic animals which are suspended in the water ; animal component of the plankton.