Case study:Shaping and protecting water-mud biotopes in Garwolin Forest division through development of small retention

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Project overview

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Status	Complete
Project web site
Themes	Environmental flows and water resources, Habitat and biodiversity
Country	Poland
Main contact forename	Ignacy, Tomasz, Tomasz, Waldemar
Main contact surname	Kardel, Okruszko, Stańczyk, Mioduszewski
Main contact user ID
Contact organisation	GWP Eastern Europe
Contact organisation web site	http://www.gwp.org/en/GWP-CEE/
Partner organisations
Parent multi-site project
This is a parent project encompassing the following projects	No

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Project summary

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When the project in the Garwolin forest was designed, it was based upon the assumption that the design of the previous water management programmes had been flawed, having negative effects on the forest. Bearing this in mind, the aims of the new project were to improve water conditions by decreasing water outflow from the forest area, and restoring the mid-forest water reservoirs and wetlands.

An important factor was to inhibit water outflow from the forest, collect and store water in reservoirs and in soils, to minimise negative impacts of potential water deficit during the summer.

The basic objective of the project was to improve the water balance by constructing small retention reservoirs that could collect snowmelt, and which also limit the fast runoff of rainwater. These measures will allow restoration and maintenance of the protected biotopes of flora and fauna connected with the water – mud environment. An additional aim of the project was to construct watering holes for forest animals. These watering holes could also be used for water collection by fire fighters in case of there would be a fire in the forest.

The effect of the implementation of the project was restoration of nearly 50 reservoirs (aquatic ecosystems) and three wetlands with the total area of 32 ha. Estimated retention capacity of the system is 523 000 m3. Retention reservoirs and other investments are scattered on an area of approximately 10 000 ha. The key feature of the project is twenty-three damming valves that aim to regulate water flows, and preserve as much water as possible in the forest.

Special attention has been given to designing the damming valves in order to increase the biodiversity of forests, and improve habitats. This has been done by ensuring that slopes are not to steep, but still allow access to water for animals, creation of islands in reservoirs to serve as breeding sites for birds, and construction of irregular shaped shore line that create favourable conditions for amphibians breeding.

Water reservoirs were located in terrain denivelations. Some of them were created by water damming and flooding of the terrain, but most of them were excavated. The damming devices were commonly concrete or wooden constructions, with valves made of wood.

Monitoring surveys and results

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It is hard to evaluate how the implemented investments contributed to flood protection. However, it is beyond doubt that the investments increased the groundwater level, and increased the soil humidity. Today, less water flows out from the forest areas. The implemented measures thus caused significant ecological effects, especially:

• restoration and maintenance of flora biotopes and animals connected with aquatic and wetlands environments;

• appearance of endangered fauna species;

• diversification of the migration trails of migrating birds in the vicinity of the Vistula valley;

• the damming devices fulfil various ecological functions such as functioning as watering holes for animals, feeding sites, breeding and rest sites for birds;

• restoration and maintenance of the biotopes of many species of fauna important to the EU e.g. fire – bellied toad, crested newt, black stork, white – tailed eagle, crane, kingfisher, European beaver, otter.

Lessons learnt

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Catchment and subcatchment Select a catchment/subcatchment Site Edit site Name WFD water body codes WFD (national) typology WFD water body name Pre-project morphology Reference morphology Desired post project morphology Heavily modified water body National/international site designation Local/regional site designations Protected species present Invasive species present Species of interest Dominant hydrology Dominant substrate River corridor land use Average bankfull channel width category Average bankfull channel width (m) Average bankfull channel depth category Average bankfull channel depth (m) Mean discharge category Mean annual discharge (m3/s) Average channel gradient category Average channel gradient Average unit stream power (W/m2) Project background Edit project background Reach length directly affected (m) Project started 2000/01/01 Works started Works completed Project completed 2010/12/31 Total cost category 100 - 500 k€ Total cost (k€) 420420 k€ <br />420,000 € <br /> Benefit to cost ratio Funding sources The total cost of the project was 1 705 000 PLN (approximately 420 000 €). Share of the input of the company “National Forests” was 27%. Funds were also obtained from the District Fund for Environmental Protection and Water Management, and from the Foundation “EkoFundusz”. The average economic efficiency indicator of the project measures by the cost of retention of 1m3 of water was 3, 26 PLN per 1m3. Cost for project phases Phase cost category cost exact (k€) Lead organisation Contact forename Contact surname Investigation and design Stakeholder engagement and communication Works and works supervision Post-project management and maintenance Monitoring Reasons for river restoration Edit reasons for restoration Mitigation of a pressure Flood risk management Hydromorphology Quantity & dynamics of flow Biology Physico-chemical Other reasons for the project Measures Edit Measures Structural measures Bank/bed modifications Floodplain / River corridor Planform / Channel pattern Other Non-structural measures Management interventions Social measures (incl. engagement) Other Monitoring Hydromorphological quality elements Edit Hydromorphological quality elements Element When monitored Type of monitoring Control site used Result Before measures After measures Qualitative Quantitative Biological quality elements Edit biological quality elements Element When monitored Type of monitoring Control site used Result Before measures After measures Qualitative Quantitative Physico-chemical quality elements Edit Physico-chemical quality elements Element When monitored Type of monitoring Control site used Result Before measures After measures Qualitative Quantitative Any other monitoring, e.g. social, economic Edit Other responses Element When monitored Type of monitoring Control site used Result Before measures After measures Qualitative Quantitative Monitoring documents Upload monitoring documents Additional documents and videos Upload additional documents Additional links and references Edit links and references Link Description Supplementary Information Edit Supplementary Information