Life+ Return of Rural Wetlands Härmälä wetland site

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Brenda Jordan
6 years ago
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1 Life+ Return of Rural Wetlands Härmälä wetland site Wildlife Habitat Flood Retention Surface Water Protection Recreational Use Landscape Biodiversity

2 What was done at Härmälä demonstrative wetland site in Sauvo, Soutwest Finland Finnish Wildlife Agency c Timo Niemelä

The objectives The objectives of the action were to create waterfowl habitat site, to halt the loss of

3 The objectives The objectives of the action were to create waterfowl habitat site, to halt the loss of biodiversity in the local area and to increase the flood retention capacity of the area for the better quality of surface water. The area was former wet meadow that was drained for agriculture and forestry, but was never dryenoughfor profitable land use. The topography of the area and the opinions of the landowner allowed the wetland to be build by damming and rising water level. After the topography measurements and action planning of the site the trees were cut down from the low laying areas around the planned wetland. The tree clearance was organized by the landowner and he used a commercial harvester for the work. Tree clearance, harvester 5,5 h x 60 / h = 330 incl. VAT Transportation of timber from site 5,5 h x 40 / h = 220 incl. VAT c Timo Niemelä

4 Preparation of the dam building The dam building was prepared by removing the surface humus and loose debris from the planned dam area, so that the dam could be build on homogenous bottom soil that forms water proof foundation for the dam structure. The old drainage tiles were removed from the dam area. c: Timo Niemelä

Assembling adjustor well The level of the well was set at

for the future maintenance of the wetland.

(200/178 mm outlet pipes) The well was assembled carefully

with the excavator. The cost of adjustor incl.

5 Assembling adjustor well The level of the well was set at the right level to allow the complete drainage of the site for the future maintenance of the wetland. All pipe connections were proofed with galvanized screws (200/178 mm outlet pipes) The well was assembled carefully in the dam abd the soil was compressed around the adjustor with the excavator. The cost of adjustor incl. transportation to the site. Adjustor well 590 incl. VAT Pipes etc. 160 incl. VAT c Timo Niemelä

6 The structure of adjustor dwell Commercial product for the water level control of the tile drained agricultural areas works well on wetlands Kuvat: Timo Niemelä

7 Dam construction The dam was build layer by layer and it the structure was compressed with the excavator several times to provide a stable and durable structure c Timo Niemelä

all the way to clean bottom soil, so that

dams was build to both sides to keep the

8 Building the dam over the old drainage ditch The bottom of the ditch was cleaned all the way to clean bottom soil, so that the actual dam material could meet the relatively dry and solid bottom soil. Before working at the ditch area worksite dams was build to both sides to keep the extra water out and to stabilize the area. ctimo Niemelä

9 Dam construction In case of unsual flooding (flash floods) a disaster pipe was assembled in the dam. The bottom of the pipe was set 28 cm above the planned water level. The dam is 3 meters wide at the top, so it can be mantained using regular farming machinery tractorsc etc. Total length ofthe dam was 90meters andaverageaverage height fromoriginaloriginal ground level 1,7 meters. The cost of dam construction: excavator 33 h x 67,65 / h = 2232,45 incl. VAT The work was done by Komatsu PC 130 excavator with fully equipped beam and bucket that could be turned to different angles c: Timo Niemelä

10 Shaping the wetland area The objective was structural diversity of the wetland: - Optimizing the area of shallow open water at low cost. - To build suitable isles and nest sites for breeding wetland birds - To increase the shoreline length and the amount of micro habitat patches and the depth variation of the site. -To provide good hydrological structure of the wetland for the good retention of nutrients and sediments - To create a site that can have positive impact for the breeding birds c: Timo Niemelä

11 The cost of excavation and soil transportation at the wetland area - excavation 10 h x 67,65 / h = 676,50 incl. VAT - soil transportation, tractor 4 h x 61,50 / h = 246 incl. VAT c: Timo Niemelä

12 The wetland will be monitored during the project Waterfolw species will be used as index species for the wetland biodiversity and well being. The landowner will carry out the waterfowl counts during the project. Wetland used by breeding waterfowl provides habitat for a number of species c: Timo Niemelä

13 The concrete action at the site was done in August The water level was kept about 40 cm below optimal level over the first winter in order to let the clay dam to settle without water pressure. c: Timo Niemelä

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19 Thank you for your attention! c: Mikko Koho

Kosteikoilla. eloa maisemaan. elinympäristöt tarvitsevat hoitoa. The habitats need management

Kosteikoilla. eloa maisemaan. elinympäristöt tarvitsevat hoitoa. The habitats need management WETLANDS LIFE TO THE Kosteikoilla LANDSCAPE eloa maisemaan elinympäristöt tarvitsevat hoitoa The habitats need management Well-managed wetlands attract birds and create life to the landscape Wetlands are