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Life+ Return of Rural Wetlands

Pikku Nuoluanjärvi Wetlands, Liminka

Text and photos: © Juha Siekkinen, Life+ Return of Rural WetlandsCover drawing: © Jari KostetMaps and aerial photos: © National Land Survey of Finland

The objectives of Pikku Nuoluanjärvi wetlands

The objectives are to Improve water quality of ditched forestry areas by binding sediments and nutrients Create habitats for wetland fauna, in particular for waterfowl Promote biodiversity, landscape and multifunctional land use Imitate beaver flooding in wetland restoration Act as demonstrative site of wetland work in the region

• Background Pikku Nuoluanjärvi wetlands consist of two basins (”The Northern wetland” and ”The

Southern wetland”) situated side by side divided by the five meters wide ditch The Northern wetland:

― built by damming the water to a higher level. Total wetland area is 4,5 hectares of which total area of open water is 2 hectares. No tree felling imitating of beaver flooding. The catchment area is 100 hectares dominated by peatlands and forestry.

The Southern wetland:― built by damming the water to a higher level. Total wetland area is 4,5 hectares

(almost all open water). The catchment area is 735 hectares dominated by intensive forestry.

The wetland project was designed and financied in collaboration with Vapo Oy, Centre for Economic Development, Transport and the Environment, The Finnish Forest Centre and Life+ Return of Rural Wetlands

The situation of Pikku Nuoluanjärvi wetlands

• The closest address is Paavolantie 125, Liminka (600 m from the Southern wetland). Car parking is 100 m from the Southern wetland.

• More information and site presentations in the field– Finnish Wildlife Agency: Juha Siekkinen +358 29 431 2404, juha.siekkinen@riista.fi (in

english)– Vapo Oy: Kari Väisänen tel. +358 20 790 5051, kari.vaisanen@vapo.fi (in finnish)

• Two wetland consists of two basins side by side. The basins are not connected to each other

• Between the basins there are the five meter wide man-made channel

THE NORTHERN WETLAND (4,5 HA)

THE SOUTHERN WETLAND (4,5 HA)

Notice board

Laser scanning image of Pikku Nuoluanjärvi area• Pikku Nuoluanjärvi was a shallow lake still in the beginning of 20th century• Legend below right: numbers indicate the elevation of ground in meters above sea level

© National Land Survey of Finland and The Finnish Forest Centre

The catchment areas of Pikku Nuoluanjärvi wetlands

Pikku Nuoluanjärvi Wetlands Restoration Project Description Map

Pikku Nuoluanjärvi wetlands before the restoration activities

• Northern wetland area was dominated by deciduous trees like birch and alder. Many trees were dying because of wet ground and seasonal flooding.

Pikku Nuoluanjärvi wetlands before the restoration activities

• Southern wetland area was dominated by deciduous trees like birch. In the western part there were an open area covered by shrubs, a total of 1,5 hectares (photo below).

Logging process in the northern wetland• Tree felling were conducted along channel in mid-april 2012. The excavator New Holland

Kobelco E 135 was equipped with the energy wood harvester head (quillotine cutting method).

• The contractor was Koneurakointi Lasse Kerälä Company (L. Kerälä in photo)

Before

Afterward

Logging process in the southern wetland• Tree felling were conducted in the beginning of april 2012. Clear-cutting were done by John Deere 970d

wheeled harvester. 40-50 cm snowcover ensured a gentle footprint on the wetland and forest floor.• All log transportation were done by Timberjack 1110 D forwarder• The contractor was Koneurakointi Lasse Kerälä Company (Taavo Robert in photo)

Water control structure in the northern wetland• Water control structure, a half-round flashboard riser was constructed to the east side of

the wetland in mid-february 2013• Flashboard riser is made from steel and has been attached to highdensity polyethylene

pipe. This combination has several advantages: they are lightweight, easy to transport and to control water level is easy and accurate.

• Water levels is regulated by placing or removing logs in the control slots to the desired elevation. Stoplogs are made of Siberian larch

• First, turf were excated away so that is was possible to ground a steady basis for the HDPE pipe and the flashboard riser combination.

• The riser were not anchored e.g. in an unmovable concrete foundation

• The riser was attached to the HPDE pipe with screws and fastened with polyurethane foam

• Finally, the filtering cloth was settled with carefully all over the riser, especially in front below to prevent leakages. The embankments around the riser were constructed afterward.

Water control structures in the southern wetland• Water control structure, the overflow dam with wooden wall was constructed to the

east side of the southern wetland in mid-february 2013• First, a frozen ground were excavated so that wooden timber were able to press in

ground. Stoplogs are made of Siberian larch for its durable and waterproof qualities.

• Larch logs in stand were mounted with steel bolts every one meter to the horizontal larch logs. Furthermore every logs in stand were nailed to the horizontal larch logs.

• The height of wall outlet was sawed to the desired lowest water level. With movable logs water level is possible to increase up to 50 cm

• The downstream was excavated and covered with filtering cloth and rocks from 5-30 cm

• The embankments around the overflow dam were constructed afterward. • In may 2013 the embankments near wooden wall had to be fixed due to leakages

caused by spring flood. Repair actions were conducted by Matti Kylmänen

• In late summer 2013 the embankments was covered mainly with natural vegetation and had worked well

Embankment constructions• The embankments were constructed in

february and march in 2013 • First, all woody vegetation and surface

turf were removed from the centerline: the core trench is one meter width and 20-40 cm deep.

• Only unfrozen fine-textured soils like silt-clay, silt or clay were used to form a tight seal with the soil already there.

• Soil for the embankment were borrowed next to the embankments The borrow areas situate 4-5 m away from the base of the embankment to prevent sloughing or caving material away from the embankment.

• The borrow areas are rather wide and shallow. They will generate new, a deeper wetland microhabitats near the shallower wetland habitats (both photos are photographed from same site)

6.2.2013 © Juha Siekkinen

8.7.2013 © Juha Siekkinen

• Photo above (26.2.2013) The embankments were constructed with 1:2 slopes. The top width of the embankments is 1-1,5 m.

• The embankments were lined with surface turf . The aim of this is to facilitate management in future like prevent tree establisment.

• Photo below (8.7.2013): Covered embankments will landscape already during the first summer

The Northern wetland of Pikku NuoluanjärviFrom degraded wetland to restorated, ”beaver-pond simulated” wetland

• Above: 20.7.2011, before restoration, below 17.8.2012 after logging along canal sides in left. © Juha Siekkinen

• Above: 22.5.2013 after all restoration actions , below 8.7.2013. © Juha Siekkinen

• Above: 7.2.2013, below: 8.7.2013

The Southern wetland of Pikku NuoluanjärviFrom degraded wetland to restorated open water wetland

• Above: 3.7.2012, logging done. Below 8.7.2013 after restoration actions © Juha Siekkinen