Quality and availability of groundwater

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4. Quality and availability of groundwater

kuva eira rosberg

There are seven groundwater abstraction sites in Lahti and five in Hollola. The renovation of the Laune groundwater abstraction site was completed in 2015 and the site was put into trial use. The site was equipped with activated carbon filters that remove even the smallest pesticide residue from the water. In addition, new chemical treatment equipment and UV systems were installed to disinfect the water before it enters the network. A water abstraction site was built at the Laune springs in 1910 and was in use until 2001, when it was closed for waterworks use after pesticide concentrations had exceeded the limit set for household water.
The quality of water is monitored in the groundwater areas, water abstraction sites and the water supply network. In 2015, the amount of water pumped for consumption in Lahti and Hollola was 8.22 million cubic metres. Water intake in the region is based solely on groundwater. All water samples taken met the quality requirements and recommendations set for household water.
Unmetered consumption rate is the indicator that represents the functioning and leakiness of the water supply network. In Lahti, the proportion of unmetered consumption relative to the amount pumped was 5.9%, which is an excellent result compared to the national average, which is about 20%. In Hollola, the unmetered consumption rate was 10.5%, which is well below the national average. The lower the unmetered consumption rate, the smaller the amount of water, energy and chemicals wasted.
In recent years, the Nastola municipality and water utility have been developing the water management system in sparsely populated areas with a focus on source water protection. In two major trunk line building projects, a total of more than 30 km of water supply trunk lines were built in Nastola with construction costs of approximately 4 million euros. The projects were carried out in cooperation with neighboring municipalities and towns as government-subsidized water supply projects. In 2015, 3 km of distribution networks were built in sparsely populated areas with connections to the trunk lines built previously. Nastola water utility received a government subsidy for the construction of the distribution network.
Nastola has six water abstraction sites. A total of 950,371 cubic metres of water was pumped from them in 2015. The water intake is based solely on groundwater and all water samples taken met the quality requirements and recommendations set for household water.

Groundwater conductivity (μS/cm), depicts the total amount of salts dissolved in the water.

Sport Centre254235224221278216217230
Hollola, Ruoppa1101051099711083106104106
Nastola, Mälkönen abstraction site172190215190220220200200210

Groundwater conductivity (μS/cm), depicts the total amount of salts dissolved in the water. Limit value is 2,500 µS/cm. Sport Centre water abstraction site hasn't been in production after 2007, because of the high amounts of pesticides. 









Atrazine levels in groundwater (μg/L)

Nastola Uusikylä (observation point GA1)2,91,310,8
Lahti (HP137, trakcside)1,62,22,31,21,8

Atrazine is a pesticide. Limit value for any particular pesticide in household water is 0.1 µg/L.





No major changes have occurred in water consumption in recent years. Specific consumption includes water used by households and industries as well as leakage.


Percentage of groundwater capacity unavailable due to contamination

Unavailable groundwater, %0141420201515152825,525,5


Water consumption (L/resident)

Lahti specific consumption197189184183179
Hollola specific consumption114113113110102
Nastola specific consumption212192211211216
Lahti household consumption127125124122121


Future challenges related to the quality and availability of groundwater:
• Ecological treatment of surface runoff
• Obtaining research data on the effects of climate change on groundwater and preparing for them
• Decontamination of polluted groundwater areas
• Raising awareness of how everyone can protect the groundwater and report hazards
• Limiting the transport of dangerous chemicals in important groundwater areas and groundwater protection 
• Renkomäki gravel abstraction site and groundwater protection 


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