Vellamo is a Tampere Water service that shows the quality of the drinking water in Tampere water supply network based on up-to-date observations and over 10,000 counting stations and geographic information.

Through Vellamo, we offer open data material presented in a searchable format. You can search the service for values describing current water quality in your area as well as browse prior information. For more detailed descriptions of the presented water quality factors, se under Information about service content.

Open data means data that is freely usable as such or has been published in a format which allows other systems to utilise it. Opening this data is intended to improve the possibilities of utilising the information published by the public sector.

Tampere Water offers a web interface to water consumers and an open interface to software developers with access to some of the data generated by the online model.

In order to reduce the number of inaccuracies, the City of Tampere has been divided into areas corresponding to statistical areas. Based on modelling results, property values are calculated for each area as the weighted average of the invoiced water consumption of the water consumers in the areas. The given area-specific values provide a description of the average status of the areas. The property values may significantly deviate form the average in the case of individual water consumers.

Water quality in Tampere complies well with health-related quality requirements and quality recommendations. Drinking water may not contain microorganisms, parasites or chemical substances in such quantities or concentrations which may be hazardous to human health. The Decree of the Ministry of Social Affairs and Health Relating to the Quality and Monitoring of Water Intended for Human Consumption sets binding health-related quality requirements as well as quality recommendations which describe the usability of drinking water in accordance with a directive.

Tampere Water constantly monitors water quality. The Rusko water purification plant laboratory analyses over 21,000 samples annually to ensure water quality. The samples are collected from raw water sources, at different stages of purification, and from the supply system. Moreover, the City of Tampere Environmental Health monitors water quality based on samples collected from different points in the water supply system.

When the service was commissioned, the four factors describing water quality below were selected to allow customers to monitor the water quality situation. The presented information comprises computational values generated using a water supply system model, based on measured observations in the actual system and water production plants. The computational results are updated every hour, so the values show an up-to-date situation in the different areas of the water supply system. Plans are underway to include similar presentations of other water quality factors in the service. We would like to receive customer feedback on service usability at tampereenvesi@tampere.fi.

pH

The pH value of water indicates the acidity of water, pH 7 being neutral. The pH value of drinking water in Tampere varies between 7.5–8.5. The quality recommendations of the Ministry of Social Affairs and Health permit a pH value of 6.5–9.5 for tap water. Natural groundwater and surface water in Finland are typically slightly acidic, with a pH value of approximately 6–7.

Even relatively acidic water may taste good and does not cause health hazards. Problems can primarily occur in the piping, when iron and copper pipes and brass connectors corrode. Green colouring under sink faucets may indicate piping corrosion due to acidic water. The water purification plant regulates pH values using lime or sodium carbonate.

Temperature

Water temperature in western Tampere stays at 7–9°C in all seasons, but varies between 1–22°C in Eastern Tampere. The surface water in eastern Tampere makes the water in that area colder in the winter than in the summer. The water in western Tampere is mainly groundwater.

No reference value is available for tap water temperature. The temperature of raw water in surface water may vary between 1–22°C. The surface water temperature usually varies from 16 to 22°C in the summer and from 1 to 4°C in the winter. Groundwater temperature varies considerably less according to season, ranging from 7 to 9°C. The temperature usually slightly increases when surface water is processed in the winter. Considerable water warming may occur within property-specific water supply systems, in particular.

The warming of water expedites chemical reactions and causes chlorine, for example, to leave the water more quickly. High water temperature increases both electrochemical and, particularly, microbiological corrosion in piping.

Chlorine

In Tampere, the microbiological quality of the water pumped into the water supply system is ensured through disinfection with chlorine or sodium hypochlorite. Chlorine is added to prevent the growth of harmful bacteria in the network. Tap water contains 0.02 to 0.4 mg/l of chlorine.

Raw water is not drinkable as such. Raw water contains impurities, such as sand, algae and bacteria and viruses hazardous to human health. The purification of drinking water involves several stages, one of which is disinfection.

Drinking water always contains chlorine because of its disinfecting qualities. Without residual chlorine, harmful microbes would increase in the water, for example when it stays longer in the piping. In Finland, drinking water is primarily disinfected using sodium hypochlorite water solution (10–15%). Using chlorine to disinfect drinking water destroys microbes by oxidising, for example, their cell walls.

The chlorine concentration in the water supply system gradually decreases as the chlorine is used up. Chlorine is better preserved in cold water than hot water. That is why water has a higher chlorine content in the winter.

Hardness

Water hardness indicates the quantity of calcium and magnesium in water. Water hardness is given either as German degrees of hardness (°dH) or as millimoles (mmol/l). 1 °dH = 0.18 mmol/l. The majority of tap water in Tampere is soft (=< 5 °dH or 0.90 mmol/l). Water near the Hyhky and Mustalampi groundwater plants is medium hard or approximately 5.5 °dH (~1 mmol/l).

Water can be divided into the following categories according to hardness:

When calcium reacts with carbon dioxide, it forms water-soluble bicarbonate. Carbon dioxide leaves water when is boiled, causing the calcium, which has dissolved in the water, to precipitate. This may show as light calcium precipitations on the surface of water or in plumbing fixtures.

While calcium and magnesium are beneficial to health, hard water impedes washing laundry. Together with soap, the calcium and magnesium ions in hard water form a calcium soap that does not dissolve in water and hampers the washing effect of the soap. This increases detergent consumption and deteriorates the washing outcome, wearing fabrics more than normal. The effectiveness of synthetic detergents also suffers from medium hard and hard water.

Calcium may also partially precipitate in the water supply system, which protects piping from corrosion. This is why most Finnish water plants add calcium to the water.

Water hardness depends on the calcium content of the soil. If calcium dissolves into water from the soil, the water becomes hard. In Finland, 95% of water supply plant and well water is soft. Greater detergent quantities are generally required in Central Europe where water mineral levels are high.

The Tampere water supply system is geographically divided into two sections which diverge at Pyynikki Ridge. The eastern section of Tampere, where the water supply system also includes Pirkkala, is clearly the largest of the two sections. Approximately 36,000 m³ of water is consumed there daily, while the corresponding figure in the western section is less than 13,000 m³. The municipality of Pirkkala consumes approximately 3,000 m³ of water daily, i.e. 8.3%. of the total.

There are two big water supply plants, Rusko and Kaupinoja, in the eastern section. Both produce high-quality drinking water from lakes Roine and Näsijärvi. The Messukylä groundwater intake, which produces approximately 5,000 m³ of water per day, is also located in the eastern section. The eastern section is divided into several pressure zones based on height: The northern section of the Linnainmaa–Leinola is included in the Atala pressure zone. Pirkkala, Hervanta, Hallila and Peltolammi–Vuores also form their own pressure zones. Each pressure zone receives water through two different pressure booster stations.

There are several, slightly smaller, groundwater intake stations in the western section: Pinsiö in Hämeenkyrö, Julkujärvi in Ylöjärvi, and Mustalampi and Hyhky in Tampere. The western section is divided into two pressure zones: the bulk of the section is included in the Tesoma pressure zone, while the Hyhky–Pispala–Pyynikki area forms its own pressure zone.

If needed, water can be pumped from east to west and vice versa using pressure booster pump stations. However, the sections primarily function separately.

In addition to Pirkkala, Tampere Water supplies water to Lempäälä and, if necessary, to Nokia, Kangasala and Ylöjärvi.

Tampere Water constantly monitors the quality of the water entering the water supply plants and water intakes and, from there, the distribution network, by conducting analyses in its own laboratories and using the automatic indicators installed in the plants. Samples are also regularly taken from numerous points along the different parts of the water supply system (such as some day-care centres). The laboratory analyses on the samples help to ensure that the water complies with all quality requirements and recommendations set for drinking water throughout the supply system. A large variety of chemical, biological and physical water properties are monitored. The Decree of the Ministry of Social Affairs and Health Relating to the Quality of and Monitoring of Water Intended for Human Consumption (STM 1352/2015) sets the quality requirements and recommendations. Tampere Water monitors other properties in addition to the ones specified in the decree.

Typical water quality properties include water acidity (pH), hardness, temperature, chlorine content, iron and manganese content as well as taste, smell and colour. The majority of the water supplied by Tampere Water is soft, i.e. its level of hardness is less than 5° dH. Water hardness is indicated either as German degrees of hardness (°dH) or as millimoles (mmol/l). The hardness of the water treated at the Rusko water purification plant is 3° dH (0.54 mmol/l) and the hardness of groundwater is 2–6° dH (0.36–1.08 mmol/l).

The laboratory results can be reviewed in the annual report and statistical information of Tampere Water (http://www.tampereenvedenvuosikertomus.fi).

Because the Tampere water supply system covers a network of approximately 780 km, not all system operations can be measured. For example, the quality samples collected from the system only give an accurate report of the situation near the point of collection at the time of collecting the sample. This is why water supply plants employ a computer model of the water supply system. The model can be used to simulate the movement of water in the network in different situations. The model can be used to analyse, for example, flows and flow rates in individual pipes as well as energy consumption and different quality factors and to examine the pressure levels of the water supply system over time. With the help of such modelling, the system operations can be examined, for example, in predicted future scenarios and different exceptional conditions, and different alternative solutions can be designed and compared.

A continuous online model has been developed for the use of Tampere Water. Every hour, the model browses the water supply plant’s automation system for the actual pumping quantities of the different water intakes and pressure booster pump stations during the previous hour as well as the surface levels of the water towers. Based on this information, the average water consumption of each pressure zone is calculated in the previous hour and a forecast is prepared for the coming day. In the model, this area-specific water consumption is divided with the number of individual water consumers in relation to their water consumption as invoiced in the previous year. In addition to the hydraulic mode, quality parameters are collected from all water intake stations during online measurement. Such online parameters include pH, chlorine content and temperature. The model is also used to calculate quality factors which are more difficult to measure, such as water retention in the network and water origin (i.e. which water intake station supplied the water). The water supply system online-modeling is developed and maintained by FCG Design and Engineering Ltd.

The model is accurate on a general level and in terms of trunk routes, but because specific information on the internal condition of individual pipes or the momentary water consumption of individual users is not available, the model always involves some inaccuracy of calculation. The closer to the periphery of the network and the smaller the subarea being examined, the greater the relative inaccuracy, even though the results are representative of the areas.

The modelling of quality factors is based on water movement in the network. The dissolution of chlorine in the network has also been roughly modelled. The internal condition of individual pipes particularly affects the exact values of chlorine and pH, so the modelling results are primarily indicative concerning these factors in particular.

Data transfer disturbances in the automation system also affect the modelling results, because the model operates completely independently and based on the automation system data without source data or result reviews.