accepted engineering principles

Those current coastal and hydraulic engineering principles, methods and procedures that would be judged by a peer group of qualified engineers (by virtue of their training and experience), as being reasonable for the scale and type of project being considered, the sensitivity of the location, and the potential threats to life and property.

accepted geotechnical principles

Those current geotechnical engineering principles, methods and procedures that would be judged by a peer group of qualified engineers (by virtue of their training and experience), as being reasonable for the scale and type of project being considered, the sensitivity of the location, and the potential threats to life and property.

accepted scientific principles

Those current principles, methods and procedures, which are used and applied in disciplines such as geology, geomorphology, hydrology, botany and zoology, and would be judged by a peer group of qualified specialists and practitioners (by virtue of their training and experience), as being reasonable for the scale and type of project being considered, the sensitivity of the location, and the potential threats to life and property.

address

Those standards and procedures intended to alleviate or reduce the impacts associated with flooding, erosion and other water related hazards which are used and applied in current coastal and hydraulic engineering, geotechnical and scientific practices.

adverse environmental impacts

Those physical, biological and environmental changes which are of long-term duration, where the rate of recovery is low, where there is a high potential for direct and/or indirect effects and/or where the areas is considered to be critical habitat or of critical significance to the protection, management and enhancement of the shoreline ecosystem.

aquifer

A water-bearing layer (or several layers) of rock or sediment capable of yielding supplies of water; typically is unconsolidated deposits or sandstone, limestone or granite; and can be classified as confined or unconfined.

artesian aquifer

An aquifer that contains water under pressure results in a hydrostatic head which stands above the local water table or above the ground level. For artesian conditions to exist, an aquifer must be overlain by a confining material and receive a supply of water.

artesian well

A well whose water is supplied by a artesian aquifer .

average annual recession rate

Refers to the average annual linear landward retreat of a shoreline or river bank.

bankfull discharge

The formative flow of water that characterizes the morphology (shape) of a fluvial channel. In a single channel stream, bankfull is the discharge which just fills the channel without flowing onto the floodplain.

baseflow

That portion of streamflow derived from groundwater storage to surface streams .

bedrockbedrock

A general term for any consolidated rock.

best management practices (BMPs)

Structural, non-structural and managerial techniques that are recognized to be the most effective and practical means to control non-point source pollutants yet are compatible with the productive use of the resource to which they are applied. BMPs are used in both urban and agricultural areas.

biodegradation

Decomposition of a substance into more elementary compounds by the action of micro-organisms such as bacteria.

biosphere

All living organisms (plant and animal life).

biotransformation

Conversion of a substance into other compounds by organisms; includes biodegradation .

bluff ( Great Lakes-St. Lawrence River system and large inland lakes)

Those sections of the shoreline formed in non-cohesive or cohesive sediments where the land rises steeply away from the water such that the elevation of the top of the slope above the base or toe of the slope is greater than two metres and the average slope angle exceeds 1:3 (=18 degrees).

bored well

A well drilled with a large truck-mounted boring auger, usually 12 inches or more in diameter and seldom deeper than 100 feet.

capillary forces

The forces between water molecules and the clay (or any soil particle) surfaces.
Capillary flow refers to water that moves in response to differences in capillary forces. It includes all water between Soil Moisture Tension = 0 and air dry.

channel configuration

The type or morphology of a river or stream channel as determined by the interaction of a number of channel related factors, including width, depth, shape, slope and pattern.

cliff ( Great Lakes-St. Lawrence River system and large inland lakes)

Those sections of the shoreline normally formed in bedrock where the land rises steeply away from the water such that the elevation of the top of the slope above the base or toe of the slope is greater than two metres and the average slope angle exceeds 1:3 (=18 degrees).

condensation

The process by which water vapour is cooled to the liquid phase.

confined aquifer

An aquifer in which ground water is confined under pressure which is significantly greater than atmospheric pressure; and whose upper, and perhaps lower, boundary is defined by a layer of natural material that does not transmit water readily. 

confining layer

Geological material through which significant quantities of water move at a very slow rate; located below unconfined aquifers , above and below confined aquifers . Also known as a confining bed.

consumptive use

Refers to the portion of water withdrawn or withheld from the Great Lakes Basin and assumed to be lost or otherwise not returned to the Basin due to evaporation, incorporation into products, or other processes.

critical flood depth and velocity

A maximum depth and velocity of flooding water in a floodplain such that further increases in depth and/or velocity may result in threats to life and property damage.

discharge

The flow of surface water in a stream or canal, or the outflow of groundwater to a well, ditch or spring .

diversions

Refers to the transfer of water from the Great Lakes Basin into another watershed, or from the watershed of one of the Great Lakes into that of another.

drainage basin

The area of land, surrounded by divides, that provides runoff to a fluvial network that converges to a single channel or lake at the outlet.

drainage water 

Water which has been collected by a gravity drainage or dewatering system.

drainage well

A pumped well in order to lower the water table; a vertical shaft to a permeable substratum into which surface and subsurface drainage is channelled.

drilled well

A well usually 10 inches or less in diameter, drilled with a drilling rig and cased with steel or plastic pipe. Drilled wells can be of varying depth.

drought

Drought is a complex term that has various definitions, depending on individual perceptions. For the purposes of low water management, drought is defined as weather and low water conditions characterized by one or more of the following:

-below normal precipitation for an extended period of time (for instance three months or more), potentially combined with high rates of evaporation that result in lower lake levels, streamflows or baseflow, or reduced soil moisture or groundwater storage

-streamflows at the minimum required to sustain aquatic life while only meeting high priority demands for water, water wells becoming dry, surface water in storage allocated to maintain minimum streamflows

-socio-economic effects occurring on individual properties and extending to larger areas of a watershed or beyond.

As larger areas are affected and as low water and precipitation conditions worsen, the effects usually become more severe

dug well

A large diameter well dug by hand or by an auguring machine, usually old and often cased by concrete or hand-laid bricks.

dynamic balance or nature

A system that is continuously altering itself to adjust to constant changes of its component parts.

effective precipitation

The part of precipitation which produces runoff ; a weighted average of current and past precipitation correlating with runoff. It is also that part of the precipitation falling on an irrigated area which is effective in meeting the requirements of consumptive use.

effluent

The discharge of a pollutant in a liquid form, often from a pipe into a stream or river. 

environmentally sound

Refers to those principles, methods and procedures involved in addressing the protection, management and enhancement of the ecosystem which are used in disciplines such as geology, geomorphology, hydrology, botany and zoology and applied in the valid study of shoreline and fluvial processes, vegetation, wildlife and aquatic habitat resource management.

erosion

The wearing away of the land surface by running water, wind, ice or other geological agents, including such processes as gravitational creep. Geological erosion is natural occurring erosion over long periods of time.

eutrophication

The natural or artificial process of nutrient enrichment whereby a waterbody becomes filled with aquatic plants and low oxygen content. The low oxygen level is detrimental to fish.

evaporation

The process by which liquid water is transferred into the atmosphere.

evapotranspiration

The combined loss of water to the atmosphere from land and water surfaces by evaporation and from plants by transpiration .

factor of safety

The ratio of resistance or strength of a material or structure to the applied load. In geotechnical engineering, it refers to the ratio of the available shear strength to shear stress on the critical failure surface.

field capacity

The capacity of soil to hold water at atmospheric pressure. It is measured by soil scientists as the ratio of the weight of water retained by the soil to the weight of the dry soil.

flood

A flood is an overflow or inundation that comes from a river or other body of water and causes or threatens damage. It can be any relatively high streamflow overtopping the natural or artificial banks in any reach of a stream . It is also a relatively high flow as measured by either gauge height or discharge quantity.

floodplain

A strip of relatively level land bordering a stream or river . It is built of sediment carried by the stream and dropped when the water has flooded the area. It is called a water floodplain if it is overflowed in times of high water, or a fossil floodplain if it is beyond the reach of the highest flood .

flow

The rate of water discharged from a source, given in volume with respect to time.

flow regime

Refers to the basin's flow magnitude and duration given a particular precipitation event (amount and intensity) and also the frequency of the events. Given the temporal component of frequency, a basin's flow regime would encompass baseflow, low magnitude (high frequency events) and high magnitude (low frequency events).

fractures

Cracks in bedrock that may result in high permeability values .

gauging station

The site on a stream , lake or canal where hydrologic data is collected.

GIS (geographic information system)

A map-based database management system which uses a spatial reference system for analysis and mapping purposes.

great lakes basin

Refers to the watershed of the Great Lakes and the St. Lawrence River upstream from Trois Rivieres , Quebec .

great lakes basin water resources

Refers to the Great Lakes and all other bodies of water (streams, rivers, lakes, connecting channels, tributary groundwater) within the Great Lakes Basin .

grey water

Domestic wastewater other than that containing human excrete, such as sink drainage, washing machine discharge or bath water.

groundwater

Water occurring in the zone of saturation in an aquifer or soil.

groundwater recharge

The inflow to a groundwater reservoir.

groundwater reservoir

An aquifer or aquifer system in which groundwater is stored. The water may be placed in the aquifer by artificial or natural means.

groundwater storage

The storage of water in groundwater reservoirs .

hardness

A characteristic of water caused by various salts, calcium, magnesium and iron (e.g. bicarbonates, sulfates, chlorides and nitrates).

herbicide

Chemicals used to kill undesirable vegetation.

high magnitude

An event that is of great importance in terms of its impacts

humification

The soil forming process that transforms plant tissues into organic matter, on or in soil.

hydraulic flow

The flow of water in a channel as determined by such variables as velocity, discharge, channel roughness and shear stress.

hydrogeologic conditions

Conditions stemming from the interaction of groundwater and the surrounding soil and rock.

hydrogeologist

A person who works and studies with groundwater .

hydrogeology

The geology of groundwater , with particular emphasis on the chemistry and movement of water.

hydrogeologic cycle

The circulation of water in and on the earth and through the earth's atmosphere through evaporation , condensation , precipitation , runoff , groundwater storage and seepage , and re- evaporation into the atmosphere.

hydrology

The study of the occurrence, distribution and circulation of the natural waters of the earth.

hydropower

Power produced by falling water.

hydrosphere

Water held in oceans, river , lakes, glaciers, groundwater , plants, animals, soil and air.

impervious

A term denoting the resistance to penetration by water or plant roots.

impoundment

A body of water, such as a pond, confined by a dam, dyke, floodgate or other barrier. It is used to collect and store water for future use or treatment.

indicator graph

Plot of monthly values of streamflow or precipitation vs. time at a station that has been designated as an indicator of conditions in that geographical location.

infiltration

The downward entry of water through the soil surface into the soil.

infiltration capacity

The maximum rate at which a given soil in a given condition can absorb rain as it falls.

infiltration rate

The quantity of water that enters the soil surface in a specified time interval. Often expressed in volume of water per unit of soil surface area per unit of time (eg. cm/hr).

irrigation

The controlled application of water for agricultural purposes through man-made systems to supply water requirements not satisfied by rainfall .

karst formations

Karst formations are limestone regions where underground drainage has formed cavities and passages that cave in, causing craters on the surface. The name comes from the Karst, a limestone region along the northern Adriatic coast in the former Yugoslavia .

lagoon

Water impoundment in which organic wastes are stored or stabilized, or both.

lakeward

A perspective from the land towards the lake or river.

landward

A perspective from the lake or river towards the land.

largest amplitude meander

The meander with the largest measured amplitude in a meandering reach. Amplitude is measured mid-channel to mid-channel and is the horizontal distance perpendicular to the longitudinal axis between two bends in the fluvial system.

leachate

Liquids that have percolated through a soil and that carry substances in solution or suspension.

leaching

The downward transport of dissolved or suspended minerals, fertilizers and other substances by water passing through a soil or other permeable material.

littoral cell

A self-contained shoreline sediment system that has no movement of sediment across its boundaries. The alongshore limits are defined by natural formations or artificial barriers where the net sediment movement changes direction or becomes zero.

low plain ( Great Lakes-St. Lawrence River system and large inland lakes)

Those sections of the shoreline formed in non-cohesive or cohesive sediments where the land rises gently away from the water.

meandering system

A dynamic system where semi-circular curves or bends develop in a fluvial system resulting from erosion of a sediment on the outer-bank and deposition of sediment on the inner-bank of the curves or bends. Erosion and deposition processes are themselves dynamic in response to channel configuration, hydraulic flow and sediment yield.

meteorology

The science of the atmosphere; the study of atmospheric phenomena.

minimum streamflow

The specific amount of water reserved to support aquatic life, to minimize pollution, or for recreation. It is subject to the priority system and does not affect water rights established prior to its institution.

moisture

Water diffused in the atmosphere or the ground.

natural flow

The rate of water movement past a specified point on a natural stream . The flow comes from a drainage area in which there has been no stream diversion caused by storage, import, export, return flow, or change in consumptive use caused by man-controlled modifications to land use. Natural flow rarely occurs in a developed area.

nitrate (NO3)

An important plant nutrient and type of inorganic fertilizer (most highly oxidized phase in the nitrogen cycle). In water, the major sources of nitrates are septic tanks, feed lots and fertilizers.

nitrite (NO2)

Product in the first step of the two-step process of conversion of ammonium (NH4) to nitrate (NO3) .

non-point source pollution

Pollution of the water from numerous locations that are hard to identify as point source. For example, agriculture and urban diffuse source runoff .

organic compounds

Natural or synthetic substances based on carbon.

outflow

Flow released from a pond or reservoir, or lakes.

over-withdrawal

Withdrawal of groundwater over a period of time that exceeds the recharge rate of the supply aquifer .

percolation

The state of water movement in the soil or aquifer ; that is, water that moves through the soil at a depth below the root zone .

permeability

The voids in a soil or aquifer media that allows passage of water through the media at a measured rate.

pH

A numerical measure of acidity, or hydrogen ion activity used to express acidity or alkalinity. Neutral value is pH 7.0, values below pH 7.0 are acid, and above pH 7.0 are alkaline.

piping

The internal erosion and carrying away of fine material from within a soil as the result of a flow of water. It refers to the pipe-shaped discharge channel left by erosion which starts at the point of exit of a flow line which exits on the ground surface; typically beneath embankments or on slopes where perched groundwater may seep out.

pockmarked topography

Refers to a Karst landscape where the land surface has the general appearance of being scarred and pitted (surface depressions, craters, etc.)

point-source pollution

Pollution of water from one place in a concentrated manner that is easy to identify. For example, effluent discharge from sewage treatment plants or industrial plants.

pollution plume

An area of a stream or aquifer containing degraded water resulting from migration of a pollutant.

porosity

The percentage of space in the soil or aquifer mass not occupied by solids with respect to the total volume of mass.

potable water

Water that is fit to drink.

ppm (parts per million)

A common basis for reporting water analysis. One ppm equals one unit of measurement per million units of the same measurement.

precipitation

Moisture falling from the atmosphere in the form of rain, snow, sleet or hail.

precipitation indicators

Precipitation is the most important and convenient indicator. Reviewing the precipitation data and comparing it to trends will warn of an impending water shortage. Two precipitation indicators are used:

Percent of average = 100 x total monthly precipitation / total average precipitation for those months. Average precipitation for the month is calculated by summing the monthly precipitation amounts for each year they were recorded at that station and dividing by the total number of years. The percent of average will be calculated for each month and indicators will be determined for the previous 18 months (long term) and the previous three months (seasonal). Under a Level I condition or higher, the previous month (short-term) will also be used, with weekly updates.
If a watershed is under a Level I or Level II condition, MNR will add up the number of consecutive readings that register no rain (less than 7.6mm).

precipitation indicator graph

Each month the actual and average monthly precipitation in millimetres (mm), are plotted for the previous 18 months. One plot shows the monthly total amounts and the other plots show the accumulated monthly totals, month by month over the 18 month period. Currently, true indicators are not used but data from selected Environment Canada Synoptic stations across south-central Ontario is plotted.

principal aquifer

The aquifer in a given area that is the important economic source of water to wells for drinking, irrigation, etc.

quality assurance

The procedural and operational framework used by modellers to assure technically and scientifically adequate execution of the tasks included in the study to assure that all analysis is reproducible and defensible.

rain guage

Any instrument used for recording and measuring time, distribution and the amount of rainfall .

rainfall

The quantity of water that falls as rain only.

reach (river and streams)

Refers to a length of channel over which the channel characteristics are stable or similar. All geomorphological features and types of aquatic habitat should be proportionately represented in the section of the river or stream being assessed, and at least two of each of the major features of the section should be represented.

recharge zone

The area of land, including caves, sinkholes, faults, fractures and other permeable features, that allows water to replenish an aquifer . This process occurs naturally when rainfall filters down through the soil or rock into an aquifer.

reservoir

A pond, lake, tank or basin (natural or human made) where water is collected and used for storage. Large bodies of groundwater are called a groundwater reservoir or aquifer; water behind a dam is also called a reservoir of water.

retrogressive failure

An unstable slope condition whereby an initial small slip in slope material results in subsequent successive segments of the slope to continue to fail, or slide, in a short period of time.

river

A natural stream of water of considerable volume.

river and stream system

A system that includes all watercourses, rivers, streams and small inland lakes (lakes with a surface area of less than 100 square kilometres) that have a measurable and predictable response to a single runoff event.

river basin

A term used to disignate the area drained by a river and its tributaries.

root zone

The depth of soil penetrated by crop roots.

runoff

The flow of water from the land to oceans or interior basins by overland flow and stream channels.

salt water intrusion

The process by which an aquifer is over-drafted, creating a flow imbalance within an area that results in salt water encroaching into the fresh water supply.

saturation

The soil in which all pore spaces are filled with groundwater .

sediment

Transported and deposited particles derived from rocks, soil or biological material. Sediment is also referred to as the layer of soil, sand and minerals at the bottom of surface water , such as streams, lakes and rivers.

seepage

The appearance and disappearance of water at the ground surface. Seepage designates the type of movement of water in saturated material. It is different from percolation , which is the predominant type of movement of water in unsaturated material.

shoreline sediment compartment

A shoreline sediment system which encompasses two littoral cells supplying depositional material to a common sink zone.

snowfall

The amount of snow, hail, sleet or other precipitation occurring in solid form which reaches the earth's surface. It may be expressed in depth in inches after it falls, or in terms of inches or millimetres in depth of the equivalent amount of water.

snowpack

The winter accumulation of snow on the ground surface.

soil moisture

Water diffused in the soil and remaining as a measurable quantity, as the volume of water divided by the total volume.

soil moisture storage

Water diffused in the soil. It is found in the upper part of the zone of aeration from which water is discharged by transpiration from plants or by soil evaporation .

spring

A place where groundwater naturally comes to the surface, resulting from the water table meeting the land surface.

spring runnoff

Snow melting in the spring causes water bodies to rise. This, in streams and rivers, is called "spring runoff".

storm

A change in the ordinary conditions of the atmosphere, which may include any or all meteorological disturbances such as wind, rain, snow, hail or thunder.

stream

A general term for a body of flowing water. In hydrology , the term is generally applied to the water flowing in a natural channel as distinct from a canal. More generally, it is applied to the water flowing in any channel, natural or artificial.

Some types of streams are: 1. Ephemeral: A stream which flows only in direct response to precipitation , and whose channel is at all times above the water table . 2. Intermittent or seasonal: A stream which flows only at certain times of the year when it receives water from spring (s) or rainfall , or from surface sources such as melting snow. 3. Perennial: A stream which flows continuously. 4. Gaining: A stream or reach of a stream that receives water from the zone of saturation . 5. Insulated: A stream or reach of a stream that neither contributes water to the zone of saturation nor receives water from it.

streamflow

The discharge that occurs in a natural channel. The term streamflow is more general than runoff , as streamflow may be applied to discharge whether or not it is affected by diversion or regulation.

stream flow indicators

Gauges in streams measure streamflow and are used to provide indicators to show there is enough streamflow in the river to meet the basic needs of the ecosystem and to show that water is available for other uses such as recreation, hydropower generation or irrigation. One streamflow indicator will be used, percentage of lowest average summer month flow. The average monthly flow for July, August and September for the streamflow station is determined and the lowest of these 3 values is the lowest average summer month flow. Monthly flow for each stream-gauge station will be compared with the lowest average summer month flow for the station to determine the streamflow indicator

Each month the average flow in cubic meters per second (m3/sec) for that month is plotted on a 1 year graph. The maximum, minimum, and mean flows for each month for that station and monthly average flows at that station for 1997 are also plotted on that graph for comparison.

Mean flow - the mean daily flow for the month indicated, for the period of record at that indicator station. Maximum flow - the maximum mean daily flow ever recorded for the month. Minimum flow - the minimum mean daily flow ever recorded for the month

surface water

Water found over the land surface in stream (s), ponds or marshes.

Three Levels of Low Water Conditions

The Level I condition is the first indication of a potential water supply problem. Level II indicates a potentially serious problem. Level III indicates the failure of the water supply to meet the demand, resulting in progressively more severe and widespread socio-economic effects.

Precipitation Indicators

Level I
18-month precipitation < 80% of average precipitation
or

3 month precipitation < 80% of average precipitation


Level II
18 month precipitation < 60% of average precipitation
or

3 month precipitation < 60% of average precipitation

or

*1 month precipitation < 60% of average precipitation

*Weeks with less than 7.6mm of rain

time lag

The time required for processes and control systems to respond to a signal or to reach a desired level. (Also referrred to as lag time.)

topography

The arrangement of hills and valleys in a geographic area.

toxic

A substance which is poisonous to an organism.

toxic pollutants

Materials contaminating the environment that cause death, disease, birth defects in organisms tht ingest or absorb them.

toxic substance

A chemical or mixture that may represent an unreasonable risk of injury to health or the environment.

toxicant

A harmful substance or agent that may injure an exposed organism.

toxicity

The quality or degree of being poisonous or harmful to plant, animal or human life.

transpiration

The process by which water vapour escapes from the living plant, principally the leaves, and enters the atmosphere.

turbidity

A measure of water cloudiness caused by suspended solids.

unconfined aquifer

An aquifer whose upper boundary is the water table .

vaporization

The change of a substance from a liquid or solid state to a gaseous state.

washoff

Storm water runoff at surface level.

water balance

The accounting of water input and output and change in storage of the various components of the hydrologic cycle .

water budgets

A summation of input, output, and net changes to a particular water resources system over a fixed period of time.

water pollution

Industrial and institutional waste, and other harmful or objectionable material in sufficient quantities to result in a measurable degradation of the water quality.

water quality

A term used to describe the chemical, physical and biological characteristics of water with respect to its suitability for a particular use.

water supply

Any quantity of available water.

water table

The water level of an unconfined aquifer , below which the pore spaces are generally saturated.

water table aquifer

An aquifer whose upper boundary is the water table ; also known as an unconfined aquifer .

water table well

A well whose water is supplied by a water table or unconfined aquifer .

watercourses

Depressions formed by runoff moving over the surface of the earth; any natural course that carries water.

watershed

All land and water within the confines of a drainage basin .

well yield

The withdrawal rate of water from a given well.

wetland

An area (including swamp, marsh, bog, prairie pothole, or similar area) having a predominance of hydric soils that are inundated or saturated by surface water or groundwater at a frequency and duration sufficient to support and that under normal circumstances supports the anaerobic condition that supports the growth and regeneration of hydrophytic vegetation.

withdrawal

Refers to removal or taking of water from surface water bodies or groundwater sources.

yield

The quantity of water expressed either as a continuous rate of flow (cubic feet per second, etc.) or as a volume per unit of time. It can be controlled for a given use, or uses, from surface water or groundwater sources in a watershed .

zone of saturation

The space below the water table in which all the interstices (pore space) are filled with water. Water in the zone of saturation is called groundwater . 

How does the hydrologic cycle affect a watershed?

Natural watershed systems maintain a balance between precipitation, runoff to lakes, rivers and wetlands, infiltration to the groundwater system, evaporation from open water surfaces and evapotranspiration from vegetation. This balance completes the natural cycle back into atmospheric moisture and precipitation.

As a general rule, in natural watersheds approximately 60% of the precipitation evaporates or transpirates back into the atmosphere, 30% infiltrates the soil and 10% runs off into surface water bodies.

The water balance for the watershed or subwatershed determines the amount of water available for aquatic ecosystem functioning and the amount available for human uses.

It is necessary to understand this "balance" or "water budget" in order to sustain the resource and its environmental and human connections in the watershed. The understanding of the hydrologic cycle on a watershed basis is essential for development and implementation of appropriate watershed management policies and procedures.