Last update
2026
Summary
The Upper Biebrza catchment (849 km²) in north-eastern Poland is a lowland catchment characterized by a mosaic of agricultural land, grasslands, forests, and extensive wetlands and water-dependent habitats. It combines relatively intact peat-wetland ecosystems in and around Biebrza National Park with more intensively managed agricultural areas, where drainage and river-maintenance activities are more pronounced. This contrast provides a valuable natural reference for investigating how groundwater and surface-water dynamics, vegetation, land use, and water management jointly control landscape water retention and river–floodplain interactions. These processes are becoming increasingly important under growing climatic pressure, particularly prolonged droughts and increasing atmospheric evaporative demand.
The case study focuses on understanding and strengthening the landscape's sponge functioning rather than reporting the performance of an already implemented intervention. Field monitoring, remote sensing, opportunity mapping, and integrated hydrological modeling are used to quantify natural water retention processes and assess the potential effects of alternative future management scenarios. Attention is given to groundwater recharge and drainage, river–floodplain interactions, and the role of evapotranspiration in controlling landscape water storage. The resulting evidence will support spatially targeted sponge strategies that improve drought resilience while safeguarding wetland biodiversity and considering extensive agricultural use.
The case study focuses on understanding and strengthening the landscape's sponge functioning rather than reporting the performance of an already implemented intervention. Field monitoring, remote sensing, opportunity mapping, and integrated hydrological modeling are used to quantify natural water retention processes and assess the potential effects of alternative future management scenarios. Attention is given to groundwater recharge and drainage, river–floodplain interactions, and the role of evapotranspiration in controlling landscape water storage. The resulting evidence will support spatially targeted sponge strategies that improve drought resilience while safeguarding wetland biodiversity and considering extensive agricultural use.
Position
Latitude
53.7372222
Longitude
23.3927777
Biogeographical Region
Continental
Project
SpongeScapes
National Id
Poland_30
Installation date
We have observed natural changes since the Park’s establ. in 1993.
Implementation Status
Contact
Warsaw University of Life Science. khmigw@sggw.edu.pl
RBD code
Biebrza do Kropiwnej
Water body code
PLRW200015262151
Transboundary
1
Photo gallery
Location of the project
The Upper Biebrza Basin is in the Podlaskie Voivodeship in north-eastern Poland. The case-study area covers the upper catchment of the Biebrza River. It includes highly valuable wetland ecosystems associated with Biebrza National Park, such as alkaline fens, transitional peatlands, and bog woodlands. The occurrence of peat soils, together with strong groundwater–surface-water interactions, gives these wetlands a high natural capacity for water retention and carbon storage.
The wider catchment forms a heterogeneous wetland–agricultural landscape. In some parts of the basin, agricultural land use is more intensive, and drainage infrastructure is more developed. In contrast, the Biebrza Valley within the National Park is characterised by extensive management and a mosaic of regularly mown areas and vegetation undergoing natural succession. This spatial contrast provides a valuable setting for assessing how drainage, vegetation dynamics, and land management influence water retention, hydrological connectivity, and low-flow conditions.
The wider catchment forms a heterogeneous wetland–agricultural landscape. In some parts of the basin, agricultural land use is more intensive, and drainage infrastructure is more developed. In contrast, the Biebrza Valley within the National Park is characterised by extensive management and a mosaic of regularly mown areas and vegetation undergoing natural succession. This spatial contrast provides a valuable setting for assessing how drainage, vegetation dynamics, and land management influence water retention, hydrological connectivity, and low-flow conditions.
NUTS Code
PL34 - Podlaskie
Project's objectives
The study of the large peat wetlands of the Upper Biebrza aims to improve our understanding of the natural ‘sponge-like’ functions of these ecosystems. By investigating the interactions between groundwater and surface water and observing the effects of Nature-based Solutions (NbS) on them we aim to gain critical insights. This knowledge will be instrumental in developing effective conservation strategies for groundwater-dependent wetlands across Europe, ensuring their sustainable future.
Involved Partners
| Authority type | Authority name | Role | Comments |
|---|---|---|---|
Climate zone
cool temperate dry
Temperature
6.8
Precipitation
556.7
Annual rainfall range
300 - 600 mm
Imperviousness range
0 - 10%
Elevation range
93.46-217.64
Slope range
Longitudinal slope on Wetaland 0.024%
Upland slop to 12%
Upland slop to 12%
Soil type
Histosols
Depth groundwater
A wetland ranging from 0.3 m at the surface to 0.5 m below the surface
Vegetation class
37% arable land
23% grasslands
26% forest
10% wetlands
4% other
23% grasslands
26% forest
10% wetlands
4% other
Water bodies: Ecological Status
moderate
Water bodies: Chemical Status
good
Project scale
Meso
Project area
7 km doliny rzeki Biebrzy (0,22km2)
Area specifications
Implementation status: research, monitoring, and scenario development are ongoing. No project-specific physical sponge intervention has yet been implemented in the Upper Biebrza case study, so the case study should not present modelled or expected benefits as measured post-implementation effects.
The design approach combines field evidence, spatial opportunity mapping and coupled modelling to move from understanding natural wetland sponge processes to evaluating potential landscape-scale sponge strategies. The main components are:
• Opportunity mapping to identify locations where changes in drainage, recharge, or wetland management could provide the greatest hydrological benefit while avoiding unsuitable or conflicting areas.
• A groundwater model based on groundwater monitoring and meteorological observations to represent subsurface flow, groundwater levels, and wetland–aquifer interactions.
• An evapotranspiration component linked to the groundwater model, supported by meteorological observations, field Leaf Area Index (LAI) measurements, and Sentinel-2 and MODIS data.
• Evaluation of combined sponge strategies at sub-catchment/catchment scale under current and future climate scenarios.
Potential management options include reducing excessive drainage, improving groundwater recharge, and rewetting or restoring hydrological connectivity where appropriate.
The design approach combines field evidence, spatial opportunity mapping and coupled modelling to move from understanding natural wetland sponge processes to evaluating potential landscape-scale sponge strategies. The main components are:
• Opportunity mapping to identify locations where changes in drainage, recharge, or wetland management could provide the greatest hydrological benefit while avoiding unsuitable or conflicting areas.
• A groundwater model based on groundwater monitoring and meteorological observations to represent subsurface flow, groundwater levels, and wetland–aquifer interactions.
• An evapotranspiration component linked to the groundwater model, supported by meteorological observations, field Leaf Area Index (LAI) measurements, and Sentinel-2 and MODIS data.
• Evaluation of combined sponge strategies at sub-catchment/catchment scale under current and future climate scenarios.
Potential management options include reducing excessive drainage, improving groundwater recharge, and rewetting or restoring hydrological connectivity where appropriate.
Area subject to Land use change or Management/Practice change (ha)
221 ha
Size
7 km
Size unit
km
Costs total information
No separate implementation budget for a physical Upper Biebrza sponge measure is reported, as the current case study focuses on monitoring, modelling, and scenario assessment. The research is undertaken within the Horizon Europe SpongeScapes project (Grant Agreement No. 101112738).
Financing authorities
Policy context
The Upper Biebrza case study is embedded in a protected wetland landscape of national, European, and international importance. Biebrza National Park is designated as a Ramsar wetland, while the Biebrza Valley includes the Natura 2000 sites Ostoja Biebrzańska (PLB200006) and Dolina Biebrzy (PLH200008). The case study is also located in a Polish region that signed the Charter of the EU Mission on Adaptation to Climate Change. At the same time, the area is becoming increasingly vulnerable to drought as climate conditions change, including higher atmospheric evaporative demand and more variable precipitation.
The central governance challenge is to reconcile several objectives that may involve important trade-offs: maintaining high groundwater levels and wetland ecological functions, protecting biodiversity, reducing drought vulnerability, and sustaining summer streamflow, while also ensuring that conservation management and extensive agricultural use remain feasible. In particular, higher groundwater and surface-water levels can enhance wetland water retention and ecological functioning, but may constrain mowing, field access, and the management of extensively used grasslands.
Against this background, the case study assesses reduced drainage, ditch blocking, and hydrological restoration as potential sponge measures, while treating mowing and other maintenance practices as management variables with possible hydrological and ecological trade-offs. The aim is to identify management strategies that enhance water retention and drought resilience while safeguarding protected wetlands and remaining compatible with existing land use.5.2 Land ownership
The land is mainly state-owned and managed by Biebrza National Park, with some privately owned areas.
The central governance challenge is to reconcile several objectives that may involve important trade-offs: maintaining high groundwater levels and wetland ecological functions, protecting biodiversity, reducing drought vulnerability, and sustaining summer streamflow, while also ensuring that conservation management and extensive agricultural use remain feasible. In particular, higher groundwater and surface-water levels can enhance wetland water retention and ecological functioning, but may constrain mowing, field access, and the management of extensively used grasslands.
Against this background, the case study assesses reduced drainage, ditch blocking, and hydrological restoration as potential sponge measures, while treating mowing and other maintenance practices as management variables with possible hydrological and ecological trade-offs. The aim is to identify management strategies that enhance water retention and drought resilience while safeguarding protected wetlands and remaining compatible with existing land use.5.2 Land ownership
The land is mainly state-owned and managed by Biebrza National Park, with some privately owned areas.
Land ownership
Biebrza National Park, residents, government agencies, and the scientific community as relevant stakeholders
Community involvment
Yes
Design consultation activity
| Activity stage | Name | Key issues | Comments |
|---|---|---|---|
|
Other
|
No formal design consultation for an implemented sponge measure is reported at this stage. Stakeholder and case-owner input can nevertheless be incorporated into opportunity mapping, management assumptions, and the selection of future scenarios.
|
Policy target
| Target purpose |
|---|
|
Increase Water Storage
|
Policy pressure
| Pressure directive | Relevant pressure |
|---|---|
Policy impact
| Impact directive | Relevant impact |
|---|---|
Requirement directive
| Requirement directive | Specification |
|---|---|
Contractual arrangements
0
| Arrangement type | Responsibility | Role | Name | Comments |
|---|---|---|---|---|
|
Not applicable at the current research/scenario stage; no project-specific implementation contract for a sponge measure is reported.
|
Part of wider plan
0
Wider plan type
| Wider plan type | Wider plan focus | Name | Comments |
|---|---|---|---|
|
No separate wider implementation plan is specified at the current research and scenario-development stage. The case study is undertaken within the conservation and management context of Biebrza National Park, Natura 2000, and the wider SpongeScapes climate-resilience framework.
|
All data for the water balance and for calibrating the groundwater model and the precipitation-runoff model
Long-term baseline data
The public SpongeScapes case-study page reports daily hydrological observations from the oldest gauges, dating back to 1948, and meteorological observations, dating back to 1961. These long records provide context for evaluating contemporary drought conditions and the variability of wetland water levels and flows.
Surface-water and groundwater monitoring
Piezometers and water-level loggers (Divers/DT-Divers) are used to track groundwater and surface-water fluctuations and gradients. Data are typically collected, and the monitoring network is inspected approximately monthly. These observations provide a direct indicator of the landscape's capacity to store water and help identify spatial differences in groundwater response and potential trade-offs with land management.
Meteorological and evapotranspiration monitoring
An automatic meteorological station records precipitation, air temperature, humidity, wind speed, and solar radiation. These data support water-balance analysis and the development of an evapotranspiration procedure/model for wetlands, which will be integrated with groundwater modelling.
Vegetation and remote sensing
Leaf Area Index (LAI) is measured monthly during the growing season (April–September in the 2024 campaign) and complemented with Sentinel-2 imagery to assess spatial variability in vegetation development.
Integrated modelling and opportunity mapping
Monitoring data are intended to support a coupled river-flow, groundwater and evapotranspiration modelling framework. Opportunity mapping is used to identify areas where hydrological restoration could improve retention. Scenario analyses will evaluate alternative management options and future climate conditions before any field implementation is considered.
The public SpongeScapes case-study page reports daily hydrological observations from the oldest gauges, dating back to 1948, and meteorological observations, dating back to 1961. These long records provide context for evaluating contemporary drought conditions and the variability of wetland water levels and flows.
Surface-water and groundwater monitoring
Piezometers and water-level loggers (Divers/DT-Divers) are used to track groundwater and surface-water fluctuations and gradients. Data are typically collected, and the monitoring network is inspected approximately monthly. These observations provide a direct indicator of the landscape's capacity to store water and help identify spatial differences in groundwater response and potential trade-offs with land management.
Meteorological and evapotranspiration monitoring
An automatic meteorological station records precipitation, air temperature, humidity, wind speed, and solar radiation. These data support water-balance analysis and the development of an evapotranspiration procedure/model for wetlands, which will be integrated with groundwater modelling.
Vegetation and remote sensing
Leaf Area Index (LAI) is measured monthly during the growing season (April–September in the 2024 campaign) and complemented with Sentinel-2 imagery to assess spatial variability in vegetation development.
Integrated modelling and opportunity mapping
Monitoring data are intended to support a coupled river-flow, groundwater and evapotranspiration modelling framework. Opportunity mapping is used to identify areas where hydrological restoration could improve retention. Scenario analyses will evaluate alternative management options and future climate conditions before any field implementation is considered.
The historic water gauge at our university, WULS in Rogożyn Stary, has been equipped with an automatic water level and temperature sensor since 2017. Flow rate checks were conducted 2–3 times a year to calibrate the equation relating water level to flow rate.
Three automatic level and temperature sensors were distributed along a 7-kilometer stretch of the river. Control flow measurements were taken at the lowest-lying sensor. The models utilized data from two lower-lying water gauges belonging to the IMGW national network in Harasimowice and Sztabin.
We have formal procedures in place for conducting all measurements.
Maintenance
Once a year, manually read the water level sensors and weather stations, clean the piezometers and sensors, and check the elevation readings. Replace the sensors with new ones once every 10 years.
Unknown
Szcowanie prowadzono z wykorzystaniem modeli matematycznych wód gruntowych i hydraulicznych oraz modelu opad odpływ SWAT.
• Groundwater level, surface-water level, and groundwater–surface-water gradients.
• River discharge, flow velocity, channel roughness, and water level/storage along monitored reaches.
• Meteorological water inputs and atmospheric demand, including precipitation and variables controlling evapotranspiration.
• Spatial patterns of drainage pressure, groundwater recharge potential, and wetland retention opportunity.
• Trade-offs between higher water levels/wetland retention, biodiversity objectives, mowing feasibility, and agricultural land use.
• River discharge, flow velocity, channel roughness, and water level/storage along monitored reaches.
• Meteorological water inputs and atmospheric demand, including precipitation and variables controlling evapotranspiration.
• Spatial patterns of drainage pressure, groundwater recharge potential, and wetland retention opportunity.
• Trade-offs between higher water levels/wetland retention, biodiversity objectives, mowing feasibility, and agricultural land use.
Key lessons
• Sponge measures need to be assessed through multiple hydrological processes rather than a single water-retention indicator. Changes in groundwater levels, soil-water storage, evapotranspiration, recharge, runoff, and streamflow jointly determine their overall effectiveness.
• The effectiveness of sponge measures is strongly variable across space and time. Responses to drainage reduction, ditch blocking, and vegetation management depend on local hydrogeological conditions, land use, vegetation, and climatic conditions, making spatial targeting essential.
• Drainage reduction and ditch blocking can improve peatland hydrological conditions, but their effects are often local rather than basin-wide. Therefore, evaluation should include the affected area and changes in groundwater depth, rather than relying solely on catchment-average water-balance indicators.
• Vegetation management influences the water balance, but its hydrological effect is context dependent. Extensive mowing can reduce evapotranspiration and seasonal water losses, although the magnitude of this effect varies from year to year and may remain limited when applied to small areas.
• Catchment-scale models are valuable for comparing management scenarios, but they simplify local processes and should not be interpreted as direct evidence of site-scale ecological outcomes. Field observations and ecological assessment should therefore complement hydrological modelling.
• The effectiveness of sponge measures is strongly variable across space and time. Responses to drainage reduction, ditch blocking, and vegetation management depend on local hydrogeological conditions, land use, vegetation, and climatic conditions, making spatial targeting essential.
• Drainage reduction and ditch blocking can improve peatland hydrological conditions, but their effects are often local rather than basin-wide. Therefore, evaluation should include the affected area and changes in groundwater depth, rather than relying solely on catchment-average water-balance indicators.
• Vegetation management influences the water balance, but its hydrological effect is context dependent. Extensive mowing can reduce evapotranspiration and seasonal water losses, although the magnitude of this effect varies from year to year and may remain limited when applied to small areas.
• Catchment-scale models are valuable for comparing management scenarios, but they simplify local processes and should not be interpreted as direct evidence of site-scale ecological outcomes. Field observations and ecological assessment should therefore complement hydrological modelling.
Success factor(s)
| Success factor type | Success factor role | Comments | Order |
|---|---|---|---|
|
Other
|
main factor
|
• Technical, ecological, data-related, and institutional.
• Enables realistic characterization of the baseline system and credible testing of alternative sponge strategies before implementation.
• The modelling framework combined field observations, remote sensing, and hydrological models to compare baseline and post-measurement scenarios.
|
Driver
| Driver type | Driver role | Comments | Order |
|---|---|---|---|
|
Other
|
main driver
|
• Climatic, hydrological, ecological, policy, and management-related.
• Main drivers for developing and testing sponge strategies. • Increasing drought pressure and low summer water levels create a need to improve retention and groundwater recharge. At the same time, Natura 2000/Ramsar conservation objectives and the extensive agricultural practices in place require solutions that are both ecologically effective and practically manageable. |
English