News

Water footprint calculator describes overall water use

17.3.2023

The water footprint calculator created by the Finnish Environment Institute is an interesting tool for examining your water footprint. This calculator available on the vesi.fi

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Sustainable use of water resources takes a leap to a new level – Finnish Environment Institute participates in historic UN Water Conference

20.3.2023

The UN Water Conference in New York on 22–24 March will mark World Water Day in an extraordinary way this year. The Finnish Environment Institute

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Finnish companies set to become leaders in water stewardship by 2030 – what does it take?

22.3.2023

A target has been set for Finnish companies to become leaders in water stewardship by 2030 as a part of the national implementation of the

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Vesi.fi – precise and up-to-date water information now also in English

17.3.2023

The Finnish Environment Institute has published an English version of its vesi.fi web service, which contains plenty of general information on water, latest snapshots of

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Finland launches an inter-ministerial water stewardship action plan in support of fair water footprints

17.3.2023

As a part of the Water Action Agenda of the UN 2023 Water Conference, Finland launches an inter-ministerial water stewardship action plan in support of

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CORRECTION: The blue-green algae situation calm both in the Baltic Sea and in lakes

8.6.2023

The blue-green algae situation has remained calm in sea areas and inland waters, as typical in early summer. Some blue-green algae observations have been made

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Groundwater sampling in Pratappur Nepal

Looking for Solutions for Arsenic in Drinking Water in Nepal

24.2.2023

Arsenic contamination of groundwater is an environmental health problem in several regions affecting many people, especially in developing countries. In Asian countries high arsenic levels

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The number of blue-green algae observations has increased slightly in inland waters and on the coast of Southwest Finland

8.8.2024

Somewhat more blue-green algae have been detected in inland waters and coastal areas than last week. Inland water observations have been made especially in the

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Expert network launched to support Finnish companies to become leaders in water stewardship by 2030

17.3.2023

The Finnish Water Stewardship Expert Network has been founded to support Finnish companies to become leaders in water stewardship by 2030. The network has been

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Earlier-than-usual observations of blue-green algae in marine areas, situation in inland waters typical for early summer

20.6.2024

The warm weather in early summer and early warming of the sea water brought forward blue-green algae observations in the offshore areas of the Gulf

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Warm weather has increased blue-green algae observations in inland waters, on the coasts and in the Gulf of Finland area

27.6.2024

The number of blue-green algae observations has increased since last week. As a result of the warmer weather, the occurrences of blue-green algae in inland

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Warm weather has increased the number of blue-green algae observations in inland waters and sea areas

13.7.2023

Observations on blue-green algae have increased this week, as a result of warm weather, both in inland waters and at sea. For example, the summer’s

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Relatively small amount of blue-green algae have been observed in inland waters, but there are plenty of observations on the coast and in the open sea

25.7.2024

The blue-green algae situation has remained stable in inland waters, and slightly less blue-green algae than in previous monitoring years have been observed. Blue-green algae

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The blue-green algae situation has remained stable since last week, unstable and windy weather slows down the growth of blue-green algae

4.7.2024

The blue-green algae situation has remained stable since last week. In inland waters, blue-green algae observations have slightly decreased, and the algae situation in coastal

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Windy and rainy weather has curbed blue-green algae blooms in lakes and sea areas

1.8.2024

Unstable weather has reduced blue-green algae blooms since last week. Cooled and rainy weather and winds have mixed the water mass and reduced blue-green algae

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Early weeks’ wind and rain have mixed the blue-green algae, observed in the southern part of the Archipelago Sea a week ago, into the entire water layer. On the left, blue-green algae in the layers close to the surface, on the right, wind-induced waves in the same area.

Cool and rainy weather has kept the blue-green algae situation calm on lakes and at sea

6.7.2023

This week, the amount of blue-green algae observations in inland waters and on the coast has been below average, as a result of cool weather

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Blue-green algae observations increased slightly in inland waters and coastal areas

15.6.2023

The blue-green algae situation remains calm, even though observations in lakes and coastal areas have increased. Abundant blooms of blue-green algae have been observed at

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Slight increase in blue-green algae observations in inland waters

11.7.2024

Blue-green algae observations have increased slightly throughout the country, and observations have been made even in Lapland. Blue-green algae now occur in the Gulf of

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Blue-green algae observations have increased in coastal and open sea areas

18.7.2024

Blue-green algae observations have increased in coastal and open sea areas, but the situation in inland waters is typical of the season. Blue-green algae have

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The satellite image shows green eddies in the sea area outside Helsinki and Porkkalanniemi.

Blue-green algae observations increased in inland waters and at sea during Midsummer week

22.6.2023

The blue-green algae situation in inland waters is calm as typical in early summer, even though blue-green algae observations have increased since last week. On

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Cyan-coloured disintegrating blue-green algae on the water.

Reduced wind increases surface blooms of blue-green algae

24.8.2023

There have been sightings of blue-green algae in almost all of Finland this week. Although the sightings have increased, the situation remains typical for inland

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Strong winds have dispersed blue-green algae surface blooms in inland waters and at sea

10.8.2023

The blue-green algae situation in lakes is calm considering the time period. Even in sea areas, blue-green algae have only been detected in subsurface layers

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The blue-green algae situation has deteriorated significantly in inland waters and coastal areas, also abundant blue-green algae in sea areas

29.6.2023

Blue-green algae observations from lakes and coastal areas have doubled since last week, as a result of warm weather. Observations have even been made in

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Blue-green algae situation has calmed down at sea and in lakes

31.8.2023

The amount of blue-green algae in sea areas and lakes has clearly decreased this week. Inland waters and coastal areas no longer have any observations

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Blue-green algae situation has remained stable both in lakes and at sea

17.8.2023

Blue-green algae observations in lakes and coastal areas have increased slightly since last week. However, the situation is normal for the season and, in lakes,

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Unstable weather has kept the blue-green algae situation calm in lakes, surface blooms observed at sea

3.8.2023

Somewhat less blue-green algae have been observed in lakes and coastal areas than last week, but blue-green algae may still appear mixed with water. Cloudy

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In the photo, sea waves hit the rocks.

Windy weather has restrained blue-green algae blooms

20.7.2023

The number of blue-green algae observations in lakes and coastal areas has decreased, due to the windy weather this week. Comprehensive satellite observations in sea

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Summer algae forecast: Warm and calm weather conditions can lead to powerful blooms of blue-green algae in the Baltic Sea

1.6.2023

In sea areas blooms of algae in the spring consume nitrogen, while leaving phosphorus-based nutrients for the blue-green algae that appear in the summer. Warm

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Proposal for 18 major flood risk areas in Finland

15.4.2024

Finland’s ELY centres propose that 18 areas in Finland should be considered zones with a significant risk of flooding in sea areas and internal water

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AI identifies amount and location of snow, water and ice in photo.

AI service for optical camera network “When will ice break?” released

31.10.2023

The new “When will ice break? service uses artificial intelligence to identify the amount and location of snow, water and ice in stream environments from game

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Water information: Short articles

Vesi.fi Tulvatilanne kuvituskuva

Quick start guide for a flood

The key is looking after your and your family’s safety. It is important to listen to and comply with the authorities’ bulletins, alarms and instructions.

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Ministry of the Environment

The Ministry of the Environment’s goal is achieving a good ecological status of Finnish lakes and rivers as well as the Baltic Sea. The attainment

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Water and wastewater services during power outages

What happens to water services if there is a power outage? Will there be water on the tap? Can I use the toilet? Water utilities

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Hanasta lasketaan juomavettä kädessä olevaan lasiin.

Where does tap water come from?

Each person in Finland normally consumes slightly over one hundred litres of water a day, while some use up to two hundred litres. Most people

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History of tap water

The history of tap water in Finland goes back 140 years. Over the decades, the quality of tap water has improved.

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Virtual water and the water footprint

Virtual or hidden water refers to all water consumed during the product’s life cycle from raw material production until the product is treated as waste.

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Protecting groundwaters is vital

Protecting groundwaters is vital because once contaminated, groundwater is extremely difficult to remediate. We can all do our share in looking after groundwaters.

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What is the price of water?

One litre of bottled water may cost several euros, compared to which the price of tap water is hardly worth mentioning. And while water from

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Kaivuri kaivaa omakotitalon vesiputkea maahan.

Who is responsible for defective water services?

Water utilities ensure that customers connected to the water distribution network are provided with tap water that meets the quality criteria.

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Natural and artificially recharged groundwater

One glance at a map reveals that Finland is a country with a lot of water. A large part of our fresh water is hidden

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Sadevesikaivo asfalttipihalla.

What is stormwater?

Stormwater is rain and drainage water conveyed away from yards and streets.

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Pihakaivosta valuu vettä saaviin.

Do we have sufficient groundwater reserves?

There is no need to worry about groundwater running out, as it is constantly replenished, whereas the contamination of groundwater is a greater risk.

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Water from a well or the tap?

Those living in the countryside have traditionally obtained their water from private wells. Water distribution and sewer networks are today also expanding to sparsely populated

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Puuvillapelto. Kuva bobbycrim Pixabaystä

Responsible water use

Water responsibility means that a company answers for its entire water consumption, including the water needed to produce the raw materials and semi-finished products it

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What makes water brown?

Rather than ever being just pure water, water from natural sources always contains many other substances, some of which stain the water.

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Is a lake thriving or not?

The waters of a lake look clear and blue. Does this mean that the lake is in a good condition? How is the status of

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Surface water varies in temperature

Surface water temperature in the sea and lakes varies following an annual cycle. Not all years are the same, however, and weather conditions have a

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Vedenkulutuksen vesimittari

Why do we pay water rates?

The basic rate collected by a water utility covers the maintenance of the water treatment plant and the distribution network, whereas the metered charge is

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Hard or soft water?

Hardness refers to the concentrations of certain minerals in water, mainly calcium and magnesium.

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How is tap water produced?

A city’s water supply plant is like a deserted spa with pumps humming, water tinkling from one basin to another and a humid smell in

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How is water management optimised in agriculture and forestry?

Catchment-level water management benefits landowners while promoting water protection and biodiversity.

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Snow and soil frost affect groundwater resources

When rainwater is infiltrated into the ground, it replenishes groundwater reserves. But what happens to groundwater in winter when precipitation falls as snow and the

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Climate change and groundwater quality

The consequences of climate change may include greater fluctuations in groundwater levels. Wintertime levels are likely to be slightly higher than today.

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Vesipsaroita sataa veden pinnalle muodostaen rinkuloita veden pintaan.

The water cycle

Water is in constant motion, moving from place to place and changing its form on the way.

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Ilmakuva järvimaisemasta jossa maaseudun asutusta.

Wastewaters in sparsely populated areas

Around one out of ten Finnish people live in sparsely populated areas not served by sewer networks, but properties in these areas are today also

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How is our drinking water supply secured in emergencies?

Water utilities are prepared for coping with various incidents. Regardless of this, situations may arise where they are forced to cut off the water supply.

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Nainen juo vettä lasista

What if my tap water is defective?

The quality of tap water is usually consistent, but sometimes you may notice a stain or funny taste in it. What causes it, and what

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Who owns water areas?

While a lake has no boundary markers, property boundaries may still run across a water body. So who owns water areas in Finland? The ownership

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How can I save water?

While water is a renewable natural resource, it is not inexhaustible. Saving water is good for both the environment and your purse.

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Wise recreational use of waters

Recreational use of waters is getting more popular and finding new forms. For recreational purposes, it is important that lakes, rivers and the sea remain

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Soil frost affects water services

For Finnish water and wastewater services, soil frost is a hard nut to crack. Its impacts must be accounted for when building a well, water

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Is the water safe for swimming?

How can you tell if water is safe to swim in? What kinds of problems can affect bathing water?

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A well must be maintained

Wells usually supply good-quality groundwater. To ensure that the water remains fresh and good for your health, however, you must look after and maintain your

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Punainen ulkokäymälä koivikossa

Wastewater treatment systems for sparsely populated areas

If you live in a rural area, you can select the treatment technique best suited for the needs of your property.

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Kaupunkinänäkymä järven rannalla.

Are population centres polluting waters?

Wastewaters produced by cities and other population centres are today treated efficiently. Do they continue to pollute waters? What about in sparsely populated areas?

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Well water quality

Well water quality should be tested regularly. A limited test should be carried out once every three years, and a more extensive analysis every six

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Sininen ja punainen vesiputki

Repairs to the water distribution network

Water pipes become dilapidated over time. If an old pipe breaks, tap water may become contaminated, which is why the water distribution network requires constant

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What is water used for?

Around one million cubic metres of water are abstracted in Finland every hour, but only a small share of this volume ends up on our

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Water resources management requires planning

The objective of water resources management is to ensure that the status of all surface water and groundwater is at least good and that it

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Is your well running dry? Report your observation!

You can report observations of dry wells on the vesi.fi web service. When the water in a well runs dry, this indicates that the groundwater

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Natural stormwater management

Natural stormwater management has many advantages: it reduces pollution in rivers and lakes, mitigates flood damage, enriches urban nature and even saves money.

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Lumpeenlehti piirtyy veden alta sinistä taivasta vasten.

How is the status of waters monitored?

Such parties as water protection associations, industrial plants, municipalities and the central government’s environmental administration take part in the monitoring.

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Peat production is declining – what does this mean for waters?

Do the emissions stop when peat is no longer harvested? The answer depends on what happens on the site.

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How much water do the Finnish lakes hold?

On a map, Finland looks like a country with a lot of water. Lakes account for around one tenth of the country’s surface area. How

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Sensitive groundwaters of coastal sulphate soils

Drought and decreased groundwater levels are consequently a particular risk in areas with acid sulphate soils.

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Climate change and seasonal water resources

Climate change is expected to increase precipitation especially in winter, and as winters will also become milder, a larger share of the precipitation will come

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Climate change increases water pollution

Climate change will affect water quality and aquatic environments in many ways, and all of the consequences cannot yet be predicted.

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Is industrial pollution still contaminating waters?

Industrial wastewater emissions are subject to stringent regulation and monitoring. Different industries have also made major investments in water protection.

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Many types of shipping and boating

The large number of different watercraft reflects the importance of waterborne transport. For centuries, the sea and inland waterways have offered a convenient way of

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Caring for your local waters

Participate in discussions and exert influence! Get involved in water protection activities in your area. By getting it right and showing consideration for aquatic environments

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Managing transboundary waters

Water bodies do not respect national borders. Rivers flow from one country to another, and a boundary may also be drawn across a lake. Finland

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Fluctuating water levels

Fed by melting snow, a river becomes a torrent in spring. In late summer the same river may look tame and quiet.

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Can water pollution from farming be reduced?

Agriculture is the greatest culprit for eutrophication in Finnish water bodies: more than one half of anthropogenic nutrient emissions come from farming.

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Ministry of Agriculture and Forestry

Water plays a key role in climate change adaptation. Together with its partners, the Ministry of Agriculture and Forestry strives to anticipate the challenges created

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Aquatic plants are sensitive to change

Aquatic plants have many tasks. They keep the water clean, bind sediments and sequester carbon dioxide, and create a sheltered habitat for other species. But

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Vesi valuu viemäriputkesta.

Where does wastewater go in the sewers?

What would life be like without underground sewers? Wastewaters would flow in open drains, and the stink would be revolting.

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Why are rivers and lakes regulated?

Water levels in lakes vary seasonally, as do flow rates in rivers. These natural cycles are altered by humans for many different reasons.

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Diverse and functioning aquatic ecosystems

Finland has not only many water bodies but also many different types of waters. Each one has its typical biocoenosis, which maintains a complicated but

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Putting price on the recreational value of waters

If the benefits created by aquatic environments can be identified and defined, they can also be accounted for in spatial planning and decision-making.

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Purjenveneet merellä

Fluctuating sea levels

People living by oceans are accustomed to tides: the sea goes in and out regularly. While there are little or no tides in the Baltic

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Local water situation

The Local water situation tool is a handy way of checking the local hydrological situation, wherever in Finland you happen to be.

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Putkia jäteveden puhdistamolla.

What goes on at a wastewater treatment plant?

The wastewater goes through a multi-stage cleaning process, each stage of which is closely monitored and precisely managed.

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Mitigating the impacts of forest drainage on waters

In the late 20th century, Finnish peatlands were drained energetically to promote silviculture. While these ditches still discharge nutrients and other substances into water bodies,

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When oxygen depletion strikes

Dead fish are floating in the water and the stink is terrible. Oxygen depletion is a hazard that usually lurks at the bottom, but in

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Government projects on water resources management

The central government has completed numerous water resources management projects to promote the management and use of aquatic resources in Finland. The range of these

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Vesinäytteen ottaja veneellä järvellä.

Indicators for a good status of waters

The objective of water resources management is to ensure that the status of all surface waters and groundwater is at least good, and that it

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Optimising land drainage with natural methods

Land drainage plays a large role in farming and forestry in Finland. Excess water must be led away in order for crops and trees to

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Are there toxins in water bodies?

Small concentrations of environmental toxins can be found in Finnish lakes and rivers. Where do they come from, and do they put human health or

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Where does water pollution come from?

While reduced emissions have helped Finnish lakes and rivers recover, they continue to be affected by diffuse pollution originating from extensive areas.

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Diversity of aquatic species

Even a small pond is teeming with life. How many different species of animals and plants are there in Finnish lakes and rivers, and which

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Finnish Environment Institute

The Finnish Environment Institute is a research and development organisation in the environmental sector that produces information and solutions for protecting and managing aquatic and

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Restoring your local waters

Restoration projects can be promoted by a village committee or management association, or sometimes a dedicated association or committee needs to be set up.

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Regulated watercourses

While many rivers in Finland have been dammed and a number of lakes are regulated, regulation does not affect all water areas.

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National Water Management and Restoration Network

The Water Management and Restoration Network is a national forum for citizens, communities, businesses and authorities interested in the status of lakes and rivers and

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The multiple aims of river and lake regulation

Any project aiming at regulating the water level or the flow of a river or lake must account for the different objectives for the use

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Invigorating rain

Rain after a period of drought is like a breath of new life for the dry earth. Plants recover and the whole world looks brighter.

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Let’s build a well!

Thousands of wells are sunk in Finland every year. What should you take into consideration when you start planning a new well?

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What causes eutrophication?

Eutrophication is caused by nitrogen and phosphorus emissions into the water. Nutrients are carried into lakes both with wastewaters and from fields and forests.

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What goes on in the world of fish?

A fish depends on the lake or river in which it lives. An ideal water body offers stable conditions but also different habitats and food

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How are industrial emissions into waters regulated?

Emissions from industrial plants are subject to the Environmental Protection Act, which aims to prevent pollution and reduce emissions.

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Flooding on the coast

A storm raised by low pressure may cause the sea level to rise quickly, and in the worst case, residential areas may be flooded and

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Microplastics in water

Microplastics are not a problem that exclusively affects the oceans. They are also found in Finnish lakes and rivers, where they can pose an environmental

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Patorakennelma, tulvavesien juoksutus.

Proactive flood prevention

Harmful floods can be prevented proactively, especially by means of river regulation, water level regulation in lakes and floodwater management.

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When water looks or smells weird

What should you do when a brook has weird scum on it or smells odd? Or funny-looking goop has washed onto the lake shore?

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What is sustainable waterborne transport like?

In waterborne transport, safety is a key issue for ensuring that neither human lives nor the wellbeing of the environment are put at risk.

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Who is allowed to dig a ditch and where?

Can you dig a drainage ditch on your own property? Do you need to notify the authorities or apply for a permit if you want

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Living at the bottom

While water is a three-dimensional environment, a large share of aquatic fauna lives at the bottom. The bottom is a safe place, but only for

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What causes fish kills?

Dead fish are floating in shallow waters along the shore while others appear to be barely alive. What has happened to the lake? Why are

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When drought strikes

Droughts are a relative matter, as what is exceptionally dry in our country may be normal elsewhere. If the rainfall amount is much lower than

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Fishing and everyone’s rights

Angling and ice fishing are free of charge for everyone. There is also no charge for herring fishing with a single rod. For other forms

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Logo ELY-keskus

ELY Centres

The customer advisers for environmental matters at ELY Centres answer questions relating to the environment and, for example, can provide guidance for initiating lake or

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Periphyton indicate the status of a water body

Pier posts covered in grey fluff, treacherous shoreline rocks, a slimy fishing net. You can find periphyton on a wide range of underwater surfaces. Periphyton

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Plankton – just drifting along

Planktonic organisms are so small that you cannot see their details with the naked eye. Under a microscope, the world of plankton opens out in

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How do you recognize blue-green algae?

You can see little specks in water. Could it be blue-green algae, or some other algae species? Or something else altogether? How can you tell

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Jalat vedessä ahventen hämmästeltävänä.

Become an amateur hydrologist!

Järvi-meriwiki is a great data resource on lakes and the sea. Why not become an amateur hydrologist or limnologist and gather data on your local

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Lieksankosken voimalaoitos, suunnittelija Alvar Aalto

History of river and lake regulation

The earliest regulation projects involved lowering the water level in lakes to gain more fertile agricultural land.

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Responsible boating

A responsible boater shows consideration for both other people and the aquatic and coastal environment.

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Shoreline restoration promotes recreational use

Many shores lose their openness gradually. Reed beds expand, the shore becomes shallower and soft silt builds up at the bottom. Could restoration make a

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Alien aquatic species

Alien species are animals or plants that have been introduced by humans, either deliberately or unknowingly.

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Springs need to be restored

If you are planning to restore a spring found on your land, contact the Finnish Forest Centre or your regional Centre for Economic Development, Transport

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Water level regulation permits

Regulation permits are granted by the Regional State Administrative Agency. When considering the matter, the Agency weighs different aspects.

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Changing climate shapes aquatic life

Aquatic flora and fauna have adjusted to our current climate. How is climate change affecting aquatic species and the entire ecosystem?

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Impacts of river and lake regulation

Regulation changes the natural flow rate or water level of a lake or river. What impacts does this have?

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Barriers to migration cut off streams

Fish and many other aquatic organisms can only move from one place to another through water. If they come across a dam or inexpertly installed

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Who makes decisions about river regulation?

The holder of a regulation permit may be a hydropower company, the central government, a land drainage company or some other operator, or even a

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Dam types

There are many types of dam constructions to meet different needs in Finland, some of which are built across rivers and lake outlets, while others

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Spring floods in rivers

The ultimate reason for a spring flood is snowmelt, and if the winter has brought a lot of snow, the spring will turn it into

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Fisheries management and restoration

The cornerstone of fisheries management and restoration is the ability of the lake or river to produce fish, which can be undermined by many factors.

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Artificial lakes serve many purposes

What is the point of constructing artificial lakes in Finland? We already have tens of thousands of lakes. Why have artificial lakes been constructed, and

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Rainstorms and flash flooding

A single day’s rainfall can exceed the usual monthly precipitation. Rainstorms cause flash flooding, especially in cities.

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Talvinen jokimaisema, hyydetulva muodostumassa jokeen.

Frazil ice causes winter floods

In winter, a river may be struck by a frazil ice flood, a peculiar phenomenon which may arise quickly if the conditions are right.

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Lumi sulaa männyn neulasista.

Where does the snow go in spring?

Snow can start disappearing very quickly in spring. Evaporation of snow mostly occurs in sunny weather when the air temperature is a few degrees above

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Which fish species are caught in Finland?

Dozens of edible fish species that provide healthy and sustainably produced food are found in Finnish waters.

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Can lakes be restored?

What should be done about a lake affected by severe eutrophication – where algae blooms and oxygen depletion are annual events or the entire lake

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Funding a restoration project

An application for a grant for a restoration project can be addressed to the central government, and the Centres for Economic Development, Transport and the

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Is fish farming a growing industry?

More than one half of all fish consumed by humans has been farmed, and Finnish people also eat more farmed than wild-caught fish.

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Can fish stocks run out?

Regeneration of fish populations is a precondition for preserving the fish fauna. Fish stocks will not run out as long as we maintain sustainable fish

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Am I living in a flood risk area?

How can I tell if my home is in a flood risk area? You can find the answer on the Finnish Environment Institute’s flood map

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Is the ice strong enough?

Fast ice, black ice, pack ice, drift ice, slush ice, grease ice. Ice comes in many forms, and you should be familiar with them before

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The annual cycles of soil frost

When the ground temperature drops below freezing, any water contained in the soil freezes. This results in soil frost, or soil that is frozen solid.

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Natural Resources Institute Finland

The Natural Resources Institute Finland’s research creates value and solutions for national and international challenges, including climate-wise carbon cycling, adaptable and resilient bioeconomy, profitable and

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Dams and stream environments

A fishway that imitates a natural brook can enrich the stream environment and partly make up for the loss of ecological values resulting from the

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Could dams be demolished?

Removing larger power plant dams would not make sense, as these plants make a contribution to climate change mitigation by producing emission-free electricity.

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Parasites are part of a healthy aquatic ecosystem

Parasites are so common in aquatic ecosystems that parasitism must be a successful way of life. Parasites’ life cycles can be highly complex, however. Many

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Preparing for floods

Society prepares for floods in many ways, and individual residents in flood risk areas can also take precautions.

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Climate change and the hydrological situation

Global climate models predict that rainfall amounts in Finland will increase by at least 5%, but possibly as much as 30%.

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How are flood risks managed?

There is a high awareness of flood risks in Finland. The authorities’ tasks related to reducing flood damage and preparing for floods are defined in

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Tapio

Tapio is a state-owned company with expertise in forest, nature and spatial data. We offer expert services based on practical experience and research evidence: reliable

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Kalatie

Fish passes

The spawning grounds of sea trout and other migratory fish often are found in the upper reaches of rivers. While dams and other barriers hinder

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Kesäinen saaristo

Height systems and the sea level

Height systems based on high-precision levelling have been used in Finland for more than a century.

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Dam safety

According to the Dam Safety Act, the owner of the dam is responsible for ensuring that the dam is safe and operates as designed.

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Valtava lumimäärä on tippunut ulkorakennuksen katolta.

How much does snow weigh?

If you live in a single-family house, the key is looking after your own and other people’s safety. You must make sure that snow sliding

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Climate change and floods

Spring floods are created when a thick layer of snow melts quickly. Climate change is reducing snow cover and bringing us milder winters and warmer

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Naamankajoen kunnostustalkoot. Kivien siirtoa veden virtaaman muuttamiseksi.

Stream restoration

Restoration can help stream habitats to recover and their typical plant and animal species to return, which also increases the recreational value of streams.

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Theme pages

Five steps of water stewardship progression

Five steps of water stewardship progression Click on the numbers to display the actions of each step.

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Regional water clusters

Four regional clusters of innovation bring together research activities and companies for productive cooperation on topical water issues and for developing smart technologies and services

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Water footprint

Water footprint describes total water use A water footprint illustrates the water intensity of our lifestyles. The greater the water footprint, the larger the volume

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World-leading research

Get familiar with Finnish research centres and the Aalto University, which have placed themselves at the very forefront of water research and cover a wide

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The Water Stewardship Commitment

The Water Stewardship Commitment The Water Stewardship Commitment challenges companies to identify water risks in their value chains and to make sure that their operation

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Colours of the water footprint

Water footprint colours Click on the numbers to see what each colour represents.

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Ways of reducing the water footprint

Ways of reducing the water footprint Click on the numbers to see how each group can make a difference.

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Kuvaaja Okko Sorma

Water stewardship

Water stewardship means that a company’s water use is not only environmentally sustainable but also socially and culturally just and economically feasible.

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Water-smart circular economy

Water-smart circular economy Water can be seen as part of circular economy. The objective of circular economy is to use the Earth’s finite natural resources

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Laitepuhdistamot

Laitepuhdistamot Laitepuhdistamot ovat tehdasvalmisteisia jäteveden käsittelyjärjestelmiä. Laitepuhdistamo on hyvä valinta jätevesien käsittelyyn erityisesti silloin, kun tontilla ei ole tarpeeksi tilaa maapuhdistamolle tai kun maaperä on kallioinen.

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Education system

Finland is known as a country that believes in education. Our education system offers the best performance at all levels for educating professionals for water-related

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Laitepuhdistamoja kaikille jätevesille

Kotitalousjätevesien käsittelyyn on suunniteltu erilaisia laite- eli pienpuhdistamoita, jotka sopivat erityisesti pienelle tontille. Alla on päivittyvä listaus Suomessa yleisesti saatavilla olevista, kaikkien kotitalousjätevesien käsittelyyn soveltuvista laitepuhdistamoista.

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Laitepuhdistamoja harmaille jätevesille

Jätevesi on niin sanottua harmaata jätevettä, jos se on peräisin ainoastaan pesemisestä, siivoamisesta, keittiöstä tai muusta vastaavasta, eikä sisällä WC-vesiä. Harmaavesipuhdistamon hankinta edellyttää, että kiinteistön

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Other pages

Finnish companies set to become leaders in water stewardship by 2030 – what does it take?

A target has been set for Finnish companies to become leaders in water stewardship by 2030 as a part of the national implementation of the

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Water glossary

Befuddled by bifurcation? Perplexed by permafrost? Mystified by mean discharge? Find aquatic entries in Water glossary

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Groundwater situation

Ajankohtainen pohjavesitilanne sekä paljon tärkeää lisätietoa pohjavesistä.

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Water situation

Koko maata koskeva yleinen vesitilanne sekä linkit alueellisiin vesitilanteisiin.

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Water glossary

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Water body

A water body is a concept used in water resources management that refers to a lake or another distinct body of water. According to the

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Classification of groundwater areas

Groundwater areas are classified on the basis of their suitability for water supply and protection needs: Class 1 comprises groundwater areas that are important for

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Groundwater level

Groundwater level describes the surface level of groundwater and its fluctuations. Factors affecting the groundwater level include the size of the groundwater body, precipitation, meltwaters,

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Water distribution area

The Health Protection Act contains provisions on water distribution areas. A water distribution area refers to a uniform part of a water distribution network where

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Raw water

Raw water is water that industrial plants and communities abstract from a surface water or groundwater source. Raw water often needs to be treated before

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Stormwater

Stormwater is water from rain and snowmelt flowing along streets and property surfaces. Stormwaters must be managed. The primary aim is to infiltrate stormwaters into

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Stormwater drain

A stormwater drain, or rainwater sewer, is a sewer that is separate from wastewater sewers. It leads away rain and drainage water accumulated in yards,

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Water and wastewater services

Water and wastewater services are an important basic function of society. The purpose of water services is to safeguard access to clean and high-quality tap

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Stormwater pond

A stormwater pond is a structure for collecting, retaining and cleaning stormwater. Stormwaters are directed to a stormwater pond either as surface runoff or through

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Water quality

Water quality is an indication of how suitable the water is for its intended use, for example as tap water. In the context of natural

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Colour of water

The colour of water varies in natural water bodies depending on the types and concentrations of coloured substances in the water. The most common substances

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Groundwater deposit

In the Water Act, a groundwater deposit refers to groundwater stored as a distinct volume of water in the saturation zone. A groundwater deposit may

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Water hardness

Water hardness describes the quantity of calcium and magnesium ions in water. The higher the quantity of these ions in water, the harder the water.

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Hidden water

Hidden water, or virtual water, refers to the amount of water contained in products. Virtual water includes all water consumed during a product’s life cycle

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Virtual water

Virtual water, or hidden water, refers to the amount of water contained in products. Virtual water includes all water consumed during the product’s life cycle

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Stormwater network

A stormwater network is a pipe network for moving away stormwaters and drainage water from building foundations. The stormwater network may consist of drain pipes

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Drinking Water Directive

The revised EU Drinking Water Directive entered into force in January 2021. Its objective is to protect citizens and the environment from the harmful effects

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Water utility report

A water utility report is a report obtained from the water services information system (VEETI) on the operation of a water utility. Various water utility

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Lentic water

Lentic water refers to water bodies with no essential flow. This means that lentic water is the opposite of flowing (lotic) water. Lentic water bodies

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Artificially recharged groundwater

Artificially recharged groundwater is groundwater whose volume has been increased by infiltrating lake or river water into the ground. In Finland, nearly 30 water utilities

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Stormwater flood

A stormwater flood occurs when it rains so heavily that the city’s stormwater system is overloaded. This means that the rainwater sewers are unable to

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Blue water footprint

The blue water footprint refers to the volume of water obtained from natural water reserves, in other words rivers, lakes and groundwater reserves, that is

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Groundwater area protection plan

A groundwater area protection plan is an account of and guideline on how groundwater should be taken into account, for example when planning land use

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Sliming

Sliming most often refers to the soiling of fish traps in water. Sliming is mainly caused by microscopic algae that adhere to the trap structures.

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Water Services Act

The objective of the Water Services Act, which was passed in 2001 and subsequently updated, is to ensure access to a sufficient amount of good-quality

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Process water

Process water refers to water used by industrial plants in their production processes. Process water usually needs to be treated before it is discharged into

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Water co-operative

A water services co-operative, or a water co-operative, is a water utility owned and managed by residents in the form of a co-operative. Water co-operatives

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Snow water equivalent

The snow water equivalent refers to the amount of water contained in snow. The water equivalent unit is kg/m2 (snow load). Its value corresponds to

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Water level

The water level describes the fluctuations of the surface level of water in the sea and lakes. Factors that affect the water level in lakes

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Domestic water treatment plant

A domestic water treatment plant is a small plant intended for treating wastewater in sparsely populated areas. It usually consists of one or more tanks,

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Groundwater body

A groundwater body is a distinct volume of groundwater within a porous and permeable soil or bedrock formation that allows a significant flow of groundwater

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Water Stewardship Commitment

A Water Stewardship Commitment is a pledge made by a company or some other organisation to develop the sustainable use and management of water in

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Water transparency

Water transparency describes the transparency and opacity of water and may also reflect its level of eutrophication. A round white disk (called a Secchi disk)

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Surface water

Surface water is water that flows or is stored above the ground. Surface waters include lakes, ponds, rivers and coastal waters.

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Surface water temperature

Surface water temperature describes thermal conditions in the surface layer of water (20 cm). The water temperature is influenced not only by the size of

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Groundwater

Groundwater refers to all water under the ground surface that fills open spaces in the ground and bedrock. Groundwater is produced when rain or surface

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Groundwater recharge area

A recharge area is an area where soil layers conduct water well and where the soil enables significant water infiltration to form groundwater. Based on

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Discharge well

A discharge well is a well in a wastewater or stormwater system from which water is discharged into a water body or to some other

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Radon

Radon is a radioactive gas that has no smell, taste or colour. It dissolves in water and can easily evaporate from water into air. Radon

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Acidity

Acidity is one of the quality elements of water. Acidity is expressed on a pH scale where the value of neutral water is 7. Fresh

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Soakaway

A soakaway, also called a seepage or leach pit, is a pit for infiltrating stormwater or other water filled with aggregate or some other material

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Hydrological model

A hydrological model is a mathematical representation of how water travels in a lake and river system and its catchment. The model describes the entire

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Hygienic quality of water

The hygienic quality of water refers to a microbiological assessment of whether the water is safe to use. The indicator of hygienic quality is the

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Water services operating area

The operating area of water services is the geographic area determined by the municipality in which water utilities provide water services.

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Grey water footprint

The grey water footprint refers to the volume of clean water that is consumed at production plants for rinsing and washing and for cleaning a

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Emergency high water level

Emergency high water level, or emergency water level, is a concept related to dam safety. It is determined on the basis of the core of

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Grey water

Grey water refers to domestic wastewater other than toilet sewage. Such activities as washing, cleaning and kitchen work produce grey water.

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Soil water

Soil water is water trapped or moving freely in soil above the groundwater surface.

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Wastewater treatment system

Wastewater treatment system refers to a method and equipment used to collect wastewater, convey it to a treatment plant and treat it. A property located

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Water Framework Directive

The Water Framework Directive, or directive establishing a framework for Community action in the field of water policy 2000/60/EC, is a European Union directive that

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Bedrock groundwater

Bedrock groundwater is groundwater that is filtered directly from precipitation or the ground into cracks in the rock. Drilled wells can be used to obtain

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Stormwater management

Stormwater management refers to measures that control stormwater accumulation or are associated with leading away and treating stormwaters.

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Surface water status

Surface water status refers to the ecological or chemical status of a water body, usually both. Surface waters are classified into five status categories based

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Water utility

Under the Water Services Act, a water utility is defined as a plant which manages the water services of a community in an area of

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Water scarcity

Water scarcity refers to a situation where water is consumed excessively in proportion to the renewable water resources that are available.

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Highest water level

The highest water level (HW), also called the high water level, is the highest water level of an observation period.

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Water storage dam

A water storage dam, or a watercourse dam, is a structure that dams water for the needs of flood protection, hydropower production or fish farming,

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Water footprint

The water footprint refers to the volume of water consumed by, for instance, a person or a state both directly and through the commodities they

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Humus

Humus is created when plant parts stored in peat or forest surface soil decay and break down. Humic substances that contain organic carbon and iron,

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Regulating dam

A regulating dam is a dam structure used to regulate volumetric flow rate and thus the level of water. The regulating dam can, for example,

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Septic tank

A septic tank is a tank intended for treating wastewater in which the solids contained in the wastewater settle down to the bottom. In former

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Electrical conductivity

Electrical conductivity is one of the parameters of water quality. It indicates the volume of minerals (salts) dissolved in water. Electrical conductivity is usually low

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Major Baltic inflow

A major Baltic inflow is a strong inflow of surface water from the North Sea into the Baltic Sea. It brings 200–300 km³ of saline

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Pit with shut-off valve

A pit with pipeline shut-off valve may be located in a water, storm water or wastewater drainage system. When the valve is closed, water flow

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Outlet channel

An outlet channel is a natural or constructed channel reserved for discharging water from a dammed reservoir, or urban stormwater or other water, into a

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Infiltration

Infiltration is a process where water enters the soil from the surface and moves downwards. Infiltration also refers to the deliberate introduction of wastewater, stormwater

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Sedimentation pond

A sedimentation pond is a water protection structure of drainage operations. It is often associated with an outlet ditch into which the waters of an

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Oxygen content

Oxygen content, or oxygen concentration, is one of the quality elements of surface waters. The amount of dissolved oxygen is associated with water temperature, which

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Flood plain

A flood plain is an elongated strip of flat ground along a waterline onto which flood water can rise. The purpose of the flood plain

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Acid sulphate soils

Acid sulphate soils are layers of soil with a high sulphur and iron content found on low-lying coasts, especially along the Gulf of Bothnia. Iron

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Brook

The Water Act defines a brook as a water body with flowing water, smaller than a river. The catchment of a brook is smaller than

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Acidification

Acidification means that the ability of a lake, forest land or other habitat to neutralise acids is reduced. As a result of acidification, the pH

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Nutrients

In water protection, nutrients usually refer to nitrogen and phosphorus. These two nutrients are primarily responsible for the eutrophication of water bodies. Based on their

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Microplastic

Plastic particles with a diameter of less than half a centimetre are referred to as microplastics. In waters, microplastics often end up in the bodies

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Lake turnover

Lake turnover refers to the complete mixing of the water masses of a lake during spring and autumn which breaks down the boundaries between different

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Roof water

Roof water is rain and meltwater running down the roofs of buildings.

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Backwater height

Backwater height is the level to which water can rise in the sewer network if, for example, a sewer is blocked.

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Small water body

Small water bodies include brooks, ponds, streamlets, ditches and springs as well as small fladas and glo lakes. Small water bodies are sensitive, which means

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Stormwater basin

A stormwater basin is a basin used or built for storing or retaining stormwaters.

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Joint property management association of a water area

A joint property management association of a water area consists of property owners who have a share in a shared water area. When a person

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Stormwater drainage system

A stormwater drainage system is a system consisting of structures intended for managing stormwaters.

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Water level regulation

Water level regulation refers to changing water levels and volumetric flow rates using dams or hydropower plant structures.

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Stormwater drainage well

A stormwater drainage well is a well for collecting stormwaters. The well may be covered by a grid. It may also have a soil or

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Mean water level

The mean water level (MW) is the average water level over a given observation period. It is expressed as height above sea level in some

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Stormwater fee

A stormwater fee is charged for conveying stormwaters into a sewer.

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Restoration of small water bodies

The aim of the restoration of small water bodies is to improve the status of brooks, ponds, springs and other small water bodies. The restoration

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Green water footprint

The green water footprint refers to the rainwater transpired by cultivated plants.

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Groundwater area

The Environmental Protection Act defines a groundwater area as an area that can be delineated based on geological criteria and within which a soil formation

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Water protection association

There are two types of water protection associations: large regional ones and smaller local ones. Local associations usually work to promote the protection or restoration

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Water temperature

Water temperature is one of the basic measurements in limnology. Temperatures measured at different depths provide information about the thermal layers in a lake or

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Stormwater infiltration structure

A stormwater infiltration structure is a system designed to promote the infiltration of stormwaters through soil layers into the ground.

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Blackwater

Blackwater refers to sewage from a flushable toilet. It contains urine and faeces, which makes it more demanding to treat than water used for washing.

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Snow load

The snow load indicates the weight of the snow layer in kilograms per square metre. This is the same as the amount of water in

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River

The Water Act defines a river as a water body with flowing water whose catchment covers at least a hundred square kilometres.

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Main channel

In the Water Act, a main channel refers to the deepest section of a river which forms a channel for the free flow of water,

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Winter drawdown

Winter drawdown is a concept related to the regulation of water bodies. It means that the water level in a lake is lowered during winter

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Ozonation

Ozonation (ozone treatment) is one way of disinfecting tap water. Ozonation is a favoured method because, unlike chlorination, it does not affect the taste of

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Two-stage channel

A two-stage channel consists of a deeper main channel and flood plains on one or both of its sides. The main channel has water throughout

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Leach field

A leach or a leaching field, also called a leaching or seepage bed, is a structure intended for treating wastewater or stormwater in which water

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Drought

Drought refers to a prolonged period of time during which an area has less water than average. A drought can be caused by lack of

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Overland flow

Overland flow is a management method for stormwaters or drainage waters in which water is allowed to flow along a plant-covered surface.

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Rain garden

A rain garden is a low-lying area with plant cover into which stormwaters can be led. The water is retained and cleaned in this area,

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Drilled well

A drilled well is a borehole drilled into the bedrock from which groundwater is extracted. The capacity of a drilled well is not very high,

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pH value

The pH value describes the acidity of water or other liquids. It is expressed on a scale of 0 to 14, where 7 is neutral,

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Pharmaceutical residues

Pharmaceutical residues refer to pharmaceutical substances that are present in wastewater. They originate in toilet sewage and have ended up there through human excretions or

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Biological oxygen demand

Biological oxygen demand (BOD) refers to the amount of oxygen consumed by organic matter in water or wastewater in a biological reaction. The majority of

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Aquascope

An aquascope is a simple tool for observing the underwater world. The cone-shaped aquascope has a transparent bottom and an opening at the top for

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Buffer strip

A buffer strip, or buffer zone, is a strip between a field or cut forest area and a water body that is not cultivated or

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Sewage sludge

Wastewater sludge, or sewage sludge, is sludge generated at sewage treatment plants. Sludge is generated when solids are removed from the wastewater and dissolved impurities

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Vaporisation

Vaporisation is the process by which water becomes water vapour at a temperature below the boiling point. During vaporisation, a heavier substance (water) becomes lighter

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Flood hazard map

Flood hazard maps describe the areas covered by water and the water depth in a flood as well as the prevailing water level with a

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Nitrate

Nitrates are inorganic nitrogen compounds. Most soluble nitrogen found in water is usually in nitrate form. An exception to this are water bodies with heavy

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Rating curve

The rating curve describes the ratio of water level and volumetric flow rate in a channel. The rating curve is obtained by measuring volumetric flow

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Flood

A flood means that the ground is temporary covered with water due to rising water or sea level, or due to stormwater build-up.

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Nitrates Directive

The so-called Nitrates Directive (Council Directive 91/676/EEC concerning the protection of waters against pollution caused by nitrates from agricultural sources) plays an integral role in

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Chemical status

The assessment of the chemical status of surface waters is based on whether or not the water fulfils the environmental quality standards for certain hazardous

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Sedimentation pit

A sedimentation pit is a water protection structure used in ditch network maintenance. It is a wider and deeper part of a field ditch with

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Fluorine

Fluorine is a base element naturally occurring in the Earth’s crust. It belongs to the halogen group. In the bedrock, fluorine is always found in

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Discharge

Discharge, or flow rate, refers to the volume of water that goes through a channel cross-section or some river basin in a certain time unit.

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Flood height

Flood height is the maximum level to which flood water rises. Flood height can be used to determine the magnitude of the largest floods observed

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Combined sewer

A combined sewer is a sewer that carries both stormwater (rainwater) and sewage. Combined sewers are no longer built, but they may still exist in

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Hydraulic engineering

Hydraulic engineering refers to construction in or affecting a water body. It includes dredging, excavation of channels, and building of embankments and dams. For example,

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Nitrogen

Nitrogen is an essential substance for all organisms. Nitrogen is often in short supply in nature, and providing plants with more nitrogen brings on lusher

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Wastewater treated on site

In sparsely populated areas, wastewaters may be processed at the point of origin rather than being led into the public sewage network.

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Iron bacteria

Iron bacteria are bacteria that oxidise iron. Their oxidation products may dye the water of a brook or a ditch brown. Iron can also rise

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Diffuse pollution

Diffuse pollution, or non-point source pollution, refers to the pollution loading of a water body that consists of several small emission sources which cannot be

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Overland flow field

An overland flow field is a natural or constructed field to which the waters from a drainage area are led. The recommended area of the

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Phosphorus filter

The purpose of a phosphorus filter is to reduce the phosphorus load caused by domestic wastewater in sparsely populated areas. A phosphorus filter may be

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Phosphorus

Phosphorus is an essential substance for all organisms. Lack of phosphorus limits algae growth in many Finnish aquatic systems. Consequently, a high phosphorus load causes

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Drainage plan

A drainage plan must be drawn up if either a permit issued pursuant to the Water Act or drainage proceedings is required for the project.

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Maximum concentration

Maximum concentration is the maximum permitted concentration of a hazardous or harmful substance, for example in tap water. The concept of maximum concentration is also

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Keystone species

A keystone species is one that offers food, shelter or a substrate for many other species. The decline or disappearance of a keystone species can

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Arsenic

Arsenic is a semi-metal that occurs naturally in the Earth’s crust. The most common arsenic mineral in Finland is arsenic sulfide. Arsenic may leach from

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Cyanobacteria

Cyanobacteria (blue-green algae) are photosynthetic bacteria that occur naturally in all bodies of surface water. Many species of blue-green algae are able to use nitrogen

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Total nitrogen

Total nitrogen refers to all nitrogen found in water: nitrogen bound in organic matter as well as dissolved nitrogen. Most of this nitrogen in water

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Organic carbon

Organic carbon is one of the parameters of ambient water quality. The amount of either dissolved organic carbon (DOC) or total organic carbon (TOC) is

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Transboundary river basin

Transboundary river basin refers to a water body that extends to both sides of a state border. Finland shares river basins with Sweden, Norway and

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Restoration plan

A restoration plan is a written document concerning a water body restoration project. It shows which restoration measures will be carried out in a water

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Zooplankton

Zooplankton consists of animals that drift or move slowly in water, most of which are microscopic. For example, zooplankton includes protozoa, rotifers and crustaceans. Their

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Pollution load

Pollution load, or loading, refers to the amount of polluting substances entering a water body. The nitrogen load, for example, is the amount of nitrogen

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Filamentous algae

Multicellular algae which form thread-like structures are known as filamentous algae. They typically grow on stone surfaces just below the waterline, but also on other

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Algae bloom

Algae bloom refers to rapid proliferation of microscopic plankton, usually blue-green algae, in the surface layer of water. In reality the algae do not produce

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Fish pass

A fish pass, or a fishway, allows fish to swim upstream in places where a dam or some other obstacle prevents their movements. A fish

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Thermocline

Thermocline and halocline are vertical layers in a lake or sea where some characteristic of the water changes rapidly in the vertical direction. The layer

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Oxygen depletion

Oxygen depletion is a situation where so little oxygen is available in the water or on the sediment surface that the biota suffers, dies or

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Ecological status

The ecological status of surface waters is assessed using a five-step scale. The assessment is primarily based on biological quality elements, such as phytoplankton, aquatic

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Soil filtration system

A soil filtration system is one option for treating wastewater in sparsely populated areas. It is based on biological activity on the surface of the

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Helmi habitats programme

The aim of the Ministry of the Environment’s Helmi programme 2021–2030 is to foster biodiversity in Finland and safeguard the ecosystem services provided by nature.

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Lake outlet

The outlet is the point in a lake where the waters are discharged downstream. The outlet determines the water level of the lake, which can

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Capillary action

Capillary action regulates the flow of a liquid, such as water, in a very thin tube or pore structure. Capillary action makes it possible for

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Sublittoral zone

The sublittoral zone is the shoreline zone below the lowest water level that is always covered with water.

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Habitat

A habitat is a living place or area of species defined by various physical and ecological factors, including the climate, topography and substrate properties. Factors

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Chemical oxygen demand

Chemical oxygen demand (COD) refers to the amount of oxygen consumed by substances in water in a chemical reaction. For example, humus and organic substances

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Turbidity

Turbidity is one of the parameters of water quality. Solids in water, including soil particles, are the main cause of turbidity. Rivers in regions with

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Suspended solids

Suspended solids are solid particles in water, such as clay, silt or sometimes particulate organic carbon. The metric for solids in water is turbidity.

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Soil infiltration

Soil infiltration is a simple way of treating wastewaters in sparsely populated areas. It can only be used for small volumes of wastewater which do

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Soil moisture

Soil moisture describes the volume of water bound to the soil. Factors that influence soil moisture are soil type, precipitation, temperature, melting of snow, evaporation

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Peak runoff control structure

A peak runoff control structure is a weir built in a sedimentation pond that can regulate the velocity of water flow. For instance, flow may

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Collecting ditch

Collecting ditches are ditches into which waters from field drains or subsurface drains are led. Collecting ditches can be equipped with water protection structures, for

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Seiche

A seiche is a standing wave in an enclosed water body. For example, seiches can occur in lakes or in the Baltic Sea as a

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Perforated casing well

A perforated casing well, or slotted tubewell, is a tubular well immersed in the ground into which water filters through the slots in the tube

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Hydrology

Hydrology is a branch of geophysics that examines the presence and properties of water and the water cycle on the Earth.

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Detention basin

A detention basin is a basin for detaining stormwaters or other waters.

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Frazil ice

Frazil ice (slush) consists of small ice crystals formed in the supercooled water of a river stretch with a strong and turbulent flow. Supercooling happens

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Open channel

An open channel refers to an open conduit of water on the ground surface in which water usually flows towards lower elevation.

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Soil frost

Soil frost, or ground frost, refers to a soil layer that hardens as the water contained in the soil freezes. Soil frost formation and depth

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Frost heaving

Frost heaving refers to an increase in volume or change in physical characteristics of the soil as it freezes. This happens due to the freezing

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Frazil ice dam

A frazil ice dam, or slush jam (hanging dam), is formed when frazil ice formed in supercooled water adheres to the bottom of a channel

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Rainfall

Rainfall, or precipitation, indicates the amount of water falling onto the ground in different forms within a certain time. One millimetre of precipitation means that

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Sediment

Sediment refers to solid materials that are transported and deposited by water, such as fine sand or clay. As the water flow decreases, the sediment

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Blue-green algae

Blue-green algae (cyanobacteria) are photosynthetic bacteria that occur naturally in all bodies of surface water. Many species of blue-green algae are able to use nitrogen

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Flood relief route

A flood relief route, or flood relief channel, is a route to which stormwaters are directed when the capacity of rainwater sewers has been exceeded.

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Precipitation

Precipitation, or rainfall, indicates the amount of water falling onto the ground in different forms within a certain time. One millimetre of precipitation means that

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Buffer zone

A buffer zone is a strip between a field or cut forest area and a water body that is not cultivated or managed and that

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Reservoir

A reservoir is an artificial water body built or dammed by humans. Reservoirs often serve as water stores for hydropower plants. The largest reservoirs in

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Enhanced nitrogen removal

Enhanced nitrogen removal refers to complementing standard wastewater treatment with special arrangements for removing nitrogen. Enhanced nitrogen removal is used especially at wastewater treatment plants

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Dredging

Dredging refers to deepening a water area by excavating or pumping sludge and sediments from the bottom. Dredging is used as one of the management

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Transboundary river basin commission

A transboundary river basin commission, or transboundary water commission, is an intergovernmental body dealing with the management and use of water bodies extending to both

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Natural drainage system

Natural drainage systems are drainage arrangements for fields which ensure the drainage capacity of channels and improve water quality. For example, pollution loads to water

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Wetland

Wetland is a common term for habitats that are covered by water during most of the year and also contain aquatic and wetland vegetation at

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Catchment restoration

Catchment restoration is a major part of a project to restore a water body. Its objective is to reduce the load entering the aquatic system

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Inspection pipe

An inspection pipe is a vertical pipe installed in an individual pipeline to facilitate inspections and maintenance of the pipe system. Inspection pipes are installed

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Frazil ice dam

A frazil ice dam, or hanging dam (slush jam), is created when frazil ice formed in supercooled water adheres to the bottom of a channel

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Point source pollution

Point source pollution refers to pollution loading of water bodies from individual sources that can be measured. Point source pollution includes emissions from municipal and

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Streamlet

The Water Act defines a streamlet as a channel smaller than a brook whose catchment is less than ten square kilometres where water does not

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Planktonic algae

Planktonic algae are microscopical algae that drift in the water along its currents. Planktonic algae are mostly single-cell organisms. They perform photosynthesis, produce oxygen in

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Eutrophication

Eutrophication refers to the proliferation of algae and other organisms performing photosynthesis due to receiving more nutrients. This results in a wide range of changes:

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Flood channel

A flood channel is either a natural or man-made channel in which water flows, or into which water is led, during a flood.

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Dam

A dam is a structure, such as a wall or embankment, whose purpose is to regulate the flow or height of water or to prevent

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Upstream

Upstream refers to the parts of a river or river basin that are above a certain point, in other words close to the upper reaches

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Submerged weir

A submerged weir is a dam structure or sill constructed below the water surface. It can be used to raise the water level of a

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Retention basin

A retention basin is a basin intended for retaining stormwaters, and it only has water some of the time.

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Stream

Stream, or lotic water, is a general concept that covers all water bodies that flow in a channel, or rivers, brooks, streamlets and ditches.

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Biofiltration area

Biofiltration areas, swales and green roofs covered with vegetation are stormwater treatment systems into which stormwaters are directed and in which they are absorbed and

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Spring complex

A spring complex refers to a connected area of land with groundwater influence, which may include open water springs, spring-fed brooks and streamlets as well

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Seepage area

A seepage area is an area of land where groundwater seeps onto the ground surface with no clear discharge area or other open water surface.

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River and lake system

A river and lake system, or water course, refers to a system of inland waters that discharge into the sea through the same river.

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Nutrient load

Nutrient load, or nutrient loading, refers to the amount of nutrients, i.e. nitrogen and phosphorus, entering a water body. Nutrients can end up in water

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Migratory fish

Migratory fish are fish species that hatch in streams, mature in the sea or a lake, and return to the same stream where they were

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Chlorophyll a

Chlorophyll a is used as an indicator of phytoplankton biomass and of the general eutrophication status of a water body. The chlorophyll a concentration varies

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Total phosphorus

Total phosphorus refers to all phosphorus found in water: phosphorus bound in soil particles and organic matter as well as dissolved phosphorus.

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Hydropower

Hydropower is a form of energy production in which water flow and height differences are used to produce electricity. The share of hydropower in all

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Minimum building elevation

Minimum building elevation refers to the level below which structures sensitive to drenching, such as the base floor of a building, should not be placed.

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Greenhouse gas

Greenhouse gases are the gases in the atmosphere that maintain the greenhouse effect. They include carbon dioxide, methane, ozone, nitrous oxide and freons. Emissions of

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Carbon dioxide

Carbon dioxide is a gaseous compound consisting of carbon and oxygen. Its chemical formula is CO2. Carbon dioxide occurs naturally in the Earth’s atmosphere at

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Overflow discharge

Overflow discharge is a situation where wastewater ends up in the environment from the sewer network or a pumping station. Overflow discharges occur in exceptional

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Regulation permit

A permit to regulate a water body is granted by the Regional State Administrative Agency. When considering a new regulation permit, the Regional State Administrative

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Fisheries restoration

The aim of fisheries restoration measures is to revive or restore natural fish populations in a water body. These measures include regulating and controlling fishing,

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Catchment

The catchment, or drainage basin, of a water body is the land area where topographic features direct any rainfall into the system in question.

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Bifurcation

In hydrology, bifurcation refers to a flow that divides into two branches that no longer join together. Bifurcations can be divided into two main types:

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Tides

Tides are periodic fluctuations in sea levels caused by the gravitational pull of the Moon and partly also the Sun. Tides in the Baltic Sea

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Black ice

Black ice, or clear ice, is hard ice formed when water freezes directly, without being mixed with snow. The bearing strength of ice is always

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Drizzle

Drizzle occurs when water droplets in the air are dense and smaller than usual (0.2–0.5 mm), allowing them to be carried along with the movements

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Infiltration rate

Infiltration rate is the rate at which water infiltrates into the ground (mm/h).

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Nature type

Nature type, or habitat type, refers to a water or land area characterized by certain biotic and abiotic features. Aquatic nature types include humic lakes

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Stage

Stage is a hydrological concept which is used to describe the water level in rivers. Factors that affect the stage of rivers include precipitation, runoff

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Stream restoration

The purpose of stream restoration is to achieve and safeguard the good ecological status of a river or other flowing water body and to promote

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River basin

A river basin is an area from which all runoff waters flow into the sea through a brook, lake, river or estuary.

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River basin district

A river basin district is an area consisting of one or more river basins for which water resources management plans are drawn up. There are

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River basin management planning

The purpose of river basin management planning is to protect and improve the status of aquatic ecosystems. The Act on the Organisation of River Basin

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Disinfection

Disinfection is a treatment phase in which bacteria and other microbes are destroyed. Disinfection is an important part of tap water production. Ozone, ultra-violate radiation

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Ecosystem

An ecosystem is a functional community of interacting organisms and their physical environment with relatively uniform ecological conditions. A lake, for example, can comprise a

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Flood protection level

Flood protection level refers to the recurrence interval or water level of a flood against which a building or activity is protected.

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Flood peak

The flood peak is the highest water level during a flood event.

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Pelagic zone

The pelagic or free water zone is the part of the surface or intermediate layer of the sea or a lake that is located outside

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Mercury

Mercury is a long-range heavy metal that accumulates in the biota. Most of the mercury in Finnish river basins originates from atmospheric deposition resulting from

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Halocline

A halocline is a vertical zone in which the salinity of sea water changes rapidly over a short distance. In the Baltic Sea, the halocline

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Pipeline inspection well

A pipeline inspection well, or a manhole, is a pit that enables checking that a sewer, stormwater or other drainage system is functioning properly as

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Infiltration amount

Infiltration amount is the volume of rainwater that is filtered by the soil (mm).

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Infiltration swale

An infiltration swale is a low-lying area or a trench with gently sloping sides that is usually dry and covered with vegetation. Stormwater may temporarily

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Permeable surface

Unbuilt or built surface where rainwater is infiltrated into the ground, for instance sand or grass.

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Biotope

A biotope is a water or land area with specific environmental conditions and characteristic plant and animal communities.

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Cavity frost

Cavity frost is characteristic for soil with a friable structure, such as a ploughed field. It is formed when water freezes on cavity walls. Cavity

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Surface run-off

Surface run-off is the amount of rainwater (mm) that, rather than being infiltrated into the ground, flows along the surface.

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Massive soil frost

Massive soil frost is typical for dense soil types. It refers to uniform soil frost with no ice-free cavities or different layers of frost. Massive

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Regulator well

A regulator well is a well connected to a subsurface drainage system used to regulate subsurface drainage runoff and thus the level of groundwater.

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Urban flood

Urban floods are caused by heavy rainfall, fluvial flooding or coastal flooding as water builds up in streets, yards and other areas, from where it

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Aquifer

An aquifer is a layer in the Earth’s crust that stores and conducts water in such quantities that a well can be made in that

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Retention

Retention is a water management term. Its purpose is to section surface runoff over a longer period.

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Separate sewer system

A separate sewer system is a pipe system in which sewage and stormwaters are kept separate.

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Calculation model

Calculation models are tools for assessing water quality, emissions or hydrological conditions when they cannot be measured directly, or anticipating them is necessary. Calculation models

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Coastal flood

A coastal flood, or a sea water flood, is caused by an exceptionally high sea level and results in the flooding of land areas. Five

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Grease ice

Grease ice is a very thin and shiny layer of ice that forms on a calm water surface overnight. Grease ice is easily broken by

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Antifouling paint

Antifouling paints are paints applied to the bottoms of boats to prevent hard shell aquatic organisms, including barnacles, from attaching to them. Antifouling paints are

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Benthic fauna

Benthic fauna are invertebrates which, at least at some stage of their life cycle, mainly live on the surfaces of the bottom or on stones,

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Drainage notification

The purpose of a drainage notification is to enable the supervisory authorities to assess whether a water permit or drainage proceedings are needed for the

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Runoff

Runoff indicates the volume of water moving on the ground surface and in the soil. Snowmelt and heavy rain increase this volume and may cause

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Drainage

In the Water Act, drainage refers to both digging a new ditch and maintaining and improving an existing drainage channel, i.e. enlarging, straightening out or

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Glo lake

A glo lake is a former sea bay that has lost contact with the sea. Over time, a glo lake becomes a freshwater lake.

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Ditch network maintenance

Ditch network maintenance refers to the cleaning of old ditches and possible excavation of additional ones. The purpose of ditch network maintenance is sufficient water

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Ditch break

A ditch break is a ditch section that has not been excavated in drainage or ditch network maintenance. Ditch breaks reduce water flow velocity and

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Dry season

A dry season can be determined on the basis of meteorological or hydrological criteria or by considering exposed sectors, including agriculture and water supply. The

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Phosphorus Decree

The Phosphorus Decree applies to the use of phosphorus in agriculture and horticulture as well as in environmental construction and landscaping. The objective of the

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Erosion control

The purpose of erosion control is to prevent soil erosion or, for example, to stop soil and nutrients leached from fields being carried to the

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Nitrates Decree

The so-called Nitrates Decree (Government Decree on Limiting Certain Emissions from Agriculture and Horticulture, 1250/2014) is based on the EU Nitrates Directive (91/676/ EEC). The

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Regulated lake

A regulated lake is a lake whose water level and flow are regulated by means of dams or other regulation structures. Around one third of

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Land drainage

Land drainage refers to moving excess water that causes damage or harm or prevents cultivation or forestry practices away from the targeted land area. Land

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Operational monitoring

Operational monitoring refers to an operator’s duty to monitor the impacts of the pollution they cause in a water body. Operational monitoring is based on

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Arterial drainage

Arterial drainage includes excavation and clearing of main ditches, the building of small embankments and improving the water capacity of brooks carried out for drainage

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Artificial lake

An artificial lake, or a man-made lake, is a lake built or dammed by humans. Artificial lakes have been built for many purposes. Many of

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Hydraulic structure

A hydraulic structure is an embankment, stream deflector, pipe, dam or other structure intended, for example, to promote flood protection, land drainage or the use

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Atmospheric deposition

Atmospheric deposition refers to materials that are deposited from the air into water or on the ground. The deposition can originate from nearby emissions or

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Field ditch

A field ditch is a ditch between field parcels which conveys water to a collector drain.

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Flame retardant

Flame retardants are chemical compounds that prevent ignition or slow down the spread of fire in a material. Flame retardants are used in textiles and

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Flow regulation

Flow regulation refers to regulating the flow of water, for example by means of dam gates or power plant turbines.

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Aquaculture

Aquaculture refers to the managed farming of fish, crayfish and other aquatic organisms in an inland water body, the sea or an artificial basin.

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Fog

Fog is a general name for water droplets floating in the air. Fog is produced if the air temperature drops to the dew point or

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Internal load

Internal load, or internal loading, refers to a situation in which phosphorus previously bound to the bottom sediment is released back into the water. Internal

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Plant nutrient

Plant nutrients are substances that plants need in order to grow. The most important plant nutrients are nitrogen, phosphorus and potassium. Of these, nitrogen and

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Blue-green algae toxins

Blue-green algae toxins are compounds produced by blue-green algae that are harmful to other organisms. Only some of the blue-green algae produce toxic compounds, and

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Dinoflagellate

Dinoflagellates are relatively large single-cell algae that belong to phytoplankton. They usually have a hard shell and two flagella that enable them to move in

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Diatom

Diatoms are single-cell algae that live separately or as colonies. Their name is derived from their Latin genus name Diatoma. Diatoms are found both on

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Phytoplankton

Phytoplankton mostly consists of single-cell algae that drift freely in water and obtain their energy from photosynthesis. Cyanobacteria, or blue-green algae, are also usually included

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Plankton

Plankton refers to small organisms that drift in the water mostly with the currents, or swim very slowly. Plankton is divided into phytoplankton and zooplankton,

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Holding tank

A holding tank, also called a wastewater holding tank, is a container attached to the toilet seat in which both solid and liquid toilet waste

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Slush ice

Slush ice, or white ice, is frozen slush. Slush ice is formed when snow presses down on the ice cover of a lake, causing water

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Submerged macrophyte

Submerged macrophytes are plant species that complete their entire life cycle submerged under water. Only its flowers may rise above the surface.

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Flada

A flada is a brackish water basin connected to the sea by a narrow inlet but gradually separating from the sea as a result of

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