Inhaltsverzeichnis
Hydrology and Desert Restoration
Does hydrology play a role in desert restoration? The answer seems yes to a layperson. Much effort is dedicated to seeds, plants, biological and socio-economic processes in desert restoration efforts. Hydrology is recognized as a key boundary condition in desertifying environments. Still, can we use it to stop desertification and trigger restoration processes or do we have to accept it as an immutable environmental condition? We propose, based on results and evidence from environmental hydrology research, that environmental hydrology can be an instrument for desert restoration. We will review findings of soil-water-atmosphere and ecohydrological process research and summarize key principles of taking into account and making use of environmental hydrological processes for desert restoration by economists and environmental managers.
State of the art
Conceptual Model of the role of hydrology in desertification and desert restoration
Latent energy and heat
Surfaces and Soils
Katalysts for storage
The role of organic matter and carbon
Fires
The role of clays and fines
The role of crusts
The role of plants
Forest effects
The role of animals
Holes, rodents
The role of man
Redistribution by runoff
2D, nested, Welwitschia
The role of rivers and ephemeral channels
WADE
Sediments and erosion
Loss of clays, silts and nutrients and carbon
The role of groundwater
Wet spots, redistribution
The role of nutrient and salt fluxes
solute traps, salinization
The role of time and residence time
Response times
Key principles of Environmental Hydrology for Restoration of Degraded Land
Energy thresholds and vapour-water transition
Distill, fog, rain, transport - more transitions, variability (stones)
Surface quality and topology
Traps and optimal distribution into surface and soil storage, capillary breaks
Modern rainwater harvesting
Size and soil structure, controlling green and blue water production
Water and sediments traps
Trap it and do not loose it in your traps
Water and carbon management
Biochar, improve storage, reduce erosion, provide carbon dioxide to plants
Water and nutrient management
Preserve your nutrients in your system
Animal Husbandry, Hydrology and Restoration
Aggregated role on crusts, sediment traps, nutrients
Land Use, Hydrology and Restoration
Put the right plans, tasks for desert restoration
Management of ephemeral channels and rivers
Resources, semi-arid, periodic dryness
Management of groundwater
Understand 3D flow pattern and re-distribution
Management of water and solute fluxes
Avoid solute traps and salinization
Validation
Kalahari - A green desert
All into the sand, lack of surface water
Cuvelai - Too much and too little
Loss of structure between channel and inter-channel area
Case Study North-East Brazil - Dam it
Dams and loss of water
Case Study South Africa - Use it (or loose it)
Lack of management of ephemeral rivers
Case Study Rwanda - Forest cover
Forest cover lost, loss of deep infiltration
An eco-hydrological perspective on desertification
What is desertification? Change in soil surface, change in redistribution of fluxes, loss of net water available to plants (green) and of net water available to humains (blue), erosion, sedimentation, loss of productivity and of stability.
An eco-hydrological perspective of restoration
Reducing erosion, storing carbon, trapping water, avoiding solute traps,
A synthesis for environmental managers and economists
Aggregate, technical measures, animal husbandry and land management measures, monitoring, understanding basin structure and time scales, targeting regions, understanding cascades of flow in basins on the surface and in groundwater
Outlook and further research
Desert restoration research site with long term monitoring: Mediterranean, Rwanda.