Dyje sub-catchment of the DRB

Organization: TGM WRI - T. G. Masaryk Water Research Institute (Czech Republic)

The Dyje basin, part of the Danube sub-catchment, faces persistent water scarcity exacerbated by climate change. Issues arise from historical manipulations at 7 dams on the Dyje/Thaya river, impacting the water supply to the extensive floodplain forest complex along the Slovakia-Austria border.

General Info

Demonstration Pilot Site 3 (DPS3) covers the Thaya River catchment in the Czech Republic (83%) and Austria (17%). The area faces water scarcity due to climate change and human activities, including reservoirs. It features diverse landscapes from highlands to lowlands, supporting agriculture and forests, though coniferous forests suffered from a recent bark beetle outbreak.

The Thaya River flows into the Morava River, forming the Lower Morava Biosphere Reserve, known for its limestone cliffs, forests, and wetlands protected under UNESCO and RAMSAR. The Dolní Morava Biosphere Reserve includes Natura 2000 sites and various protected areas, highlighting its biodiversity and environmental importance.

What measures have been taken?

Revitalization Initiatives in the Thaya Basin:

• Research Application from Lower Morava Biosphere Reserve:
  • Tailored actions as blueprint for Dalia project replication.
• Focus on Wetland Restoration:
  • Addressing historical human impacts on floodplains.
  • Mitigating effects of water management projects altering hydrology.
• Contribution of Ramsar Convention Wetlands:
  • Lednice Fishponds and Floodplain of Lower Dyje River.
  • Global efforts in wetland and waterfowl habitat protection.
• Post-1989 Revitalization Efforts:
  • Involvement of public-private partnerships.
  • Restoration projects like Allahy forest ponds and Obelisk floodplain.
• Upcoming Thaya River Dam Project:
  • Part of Giving Water Back to the Forest program.
  • Goals: Raise water levels, irrigate floodplain forests, enhance canal system.
• Legal Protection and Landscape Declaration:
  • Negotiations for Soutok Protected Landscape Area.
  • Comprehensive commitment to environmental preservation.

Environmental Impact

Historical River Management:

• Focus on technical adjustments for drainage and flood protection.
• Resulted in negative environmental impacts during the 19th and 20th centuries.

Emergence of Revitalization Schemes:

• Aim to understand and restore natural processes.
• Goals include enhancing biodiversity, managing pollution, and mitigating floods and droughts.

Challenges in Revitalization Efforts:

• Balancing conflicting interests:
  • Impact on bird populations.
  • Protection of endangered plant species.

Ecosystem Approach in Projects:

• Integration of river and floodplain habitats.
• Crucial for sustainable management and biodiversity conservation.

Contribution of Renaturation Measures:

• Implemented and planned actions:
  • Both inside and outside the Soutok site.
• Aim to increase resilience through ecosystem restoration.

Recommendations

Central European floodplain forests, known for biodiversity, face challenges including dam impacts causing loss of over 1000 hectares. Measures like meander restoration, controlled flooding, and wetland rehabilitation are underway. Future plans include a new flap weir by 2025. The Dalia project aims to refine hydrological balance through precise measurements, addressing water losses due to evaporation amid climate change concerns.