There are countless little lakes, ponds and brooks as well as small mires in the National Park.

Nuuksio National Park comprises more than 80 small lakes and ponds. They range from brown-water ponds surrounded by fens to lakes with clear waters and rocky shores. The best-known ones are Haukkalampi, Mustalampi, Nuuksion Pitkäjärvi and the valuable bird wetland of Matalajärvi. The lakes are fairly evenly distributed around the park.
Lake Matalajärvi is a nutrient-rich lake included in the national bird wetland conservation programme. The name of this lake refers to shallows, and its maximum water depth indeed is little more than one metre even in open water areas. The spring-fed lake is naturally rich in nutrients. Lake Matalajärvi is one of the few naturally nutrient-rich lakes with highly representative vegetation that have been preserved in a relatively natural condition. Especially during migrations, there are plenty of birds to watch on the lake, including waders and many aquatic birds. In the autumn, smews may visit the lake.
There are many brooks in Nuuksio that keep flowing throughout the year, as well as smaller rivulets that dry out regularly. The main artery of the park is Myllypuro brook which discharges into Nuuksion Pitkäjärvi Lake. Its valley is one of the core areas of the National Park from the perspective of especially natural values but partly also hiking. The sources feeding Myllypuro include the Parikas Lakes. Nahkiaispolku trail treats visitors to a closer look at Myllypuro brook.
A large number of birds live in the waters and on the shores. The black-throated diver (*Gavia arctica*) favours slightly larger lakes, while the red-throated diver (*Gavia stellata*) prefers smaller lakes and ponds. You may spot the osprey (*Pandion haliaetus*) fishing in a lake, many species of ducks nest in the smaller water bodies of this area, and the dipper (*Cinclus cinclus*) sometimes spends the winter by the larger brooks. A lucky hiker may encounter an otter (*Lutra lutra*) in the park, or at least see its tracks in the snow.
The water quality in Nuuksio’s small water bodies is moderately good. The nutrient-poor upland lakes suffered from acidification in the 1980s but have recovered well. Today, eutrophication is a greater threat. Using detergents and washing dishes in the lakes and brooks should be avoided.

The Finnish Nature Centre Haltia and hiking information