HW10 - Global management strategies for the WATER cycle

Improving forestry techniques

Improving forestry techniques can play an important role in supporting the water cycle by enhancing infiltration, reducing runoff, and maintaining soil moisture.

Examples and evidence of IMPROVING FORESTRY TECHNIQUES

• Agroforestry and mixed-species planting - Kenya’s Green Belt Movement

Found in 1977, the project has planted over 51 million trees, reducing runoff and improving infiltration in catchments such as The Tana River. Agroforestry in east Africa can cut soil erosion by up to 65% and boost soil water storage by 20% compared to open farmland.

• Sustainable forest management - Costa Rica

The Payment for Environmental Services (PES) scheme has helped forest cover rise from 21% in the 1980s to over 53% today, stabilising rainfall and maintaining streamflow that supports 98% of hydropower generation.

• Reforestation and riparian restoration - China’s Loess Plateau Project

Restoring 35,000km2 of degraded land (1994-2005) cut soil erosion by over 70% and doubled vegetation cover, improving groundwater recharge and reducing flood risk.

Riparian refers to areas of land alongside rivers, streams, or other bodies of freshwater

Strengths of IMPROVING FORESTRY TECHNIQUES

• stabilising the regional water cycle

• can offset around 1.4 billion tonnes of carbon a year

• supporting indigenous forest communities

• protecting the generic bank provided by thousands of plant species in the forests

Limitations of IMPROVING FORESTRY TECHNIQUES

• skills gap - lack of knowledge, awareness and education to implement this.

• can create monocultures which are vulnerable to disease and reduces biodiversity

• not all areas are protected

What is water allocations?

Water allocations refer to the planned distribution and management of limited freshwater resources between users such as agriculture, industry, and households, aiming to ensure sustainable use and maintain balance within the water cycle.

Examples and evidence of WATER ALLOCATION

• Colorado River Compact (USA) - allocates 16 billion m3/year of water among seven states; while it provides water for 5 million hectares of farmland, heavy irrigation withdrawals mean that the river often falls to reach its delta, reducing groundwater recharge and affecting wetland ecosystems.

• Indus Waters Treaty (Pakistan and India) - divides the Indus River system so that Pakistan receives 92% of the river’s flow; this supports irrigation for over 18 million hectares of farmland and helps maintain groundwater levels in semi-arid regions.

• Murray-Darling Basin Plan (Australia) - sets extraction caps of 12,000 GL/year across multiple states; environmental water allocations have restored flows to key wetlands and rivers, with over 1000 GL/year specifically reserved to improve river health and support floodplain ecosystems.

Strengths of WATER ALLOCATION

• increases water use efficiency and preserves resource for future use.

• promotes fair and equitable distribution of water resources.

Limitations of WATER ALLOCATION

• competition for water allocation can result in local, national, or regional geopolitical conflicts, particularly in areas where rivers cross state or national borders.

• often prioritises human uses of water rather than environmental considerations

• can be difficult to actually monitor water use

What is DRAINAGE BASIN MANAGEMENT?

Drainage basin management allows a holistic approach to balance competing demands from agriculture, industry, domestic use, wildlife, and recreation, protecting water quality, river flow, groundwater, and biodiversity.

Runoff control is achieved through reforestation, reducing artificial drainage, and increasing permeable surfaces in urban areas (e.g. gardens, green roofs).

Surface water storage is enhanced by wetland conservation and floodplain restoration while groundwater levels are maintained by limiting abstraction and using artificial recharge via boreholes.

Examples and evidence of DRAINAGE BASIN MANAGEMENT?

Thames River Basin (England) - managed under the EU Water Framework Directive, covering about 17,000 km2 and supplying water to 15 million. Drainage basin planning includes wetlands restoration, floodplain management and groundwater recharge schemes.

These measures have reduced flood risks in urban areas, improved river water quality (with nitrate and phosphate levels falling by up to 25% in monitored rivers) and helped maintain groundwater levels critical for public supply and agriculture.

Reforestation and increased permeable surfaces in urban catchments have also slowed rapid runoff, allowing rivers to retain more water and support local ecosystems.

Strengths of DRAINAGE BASIN MANAGEMENT

• Balances environmental considerations with human usage needs

• protects both surface water and groundwater storage supplies

• very effective at a global scale as it can target a variety of stores at once

Limitations of DRAINAGE BASIN MANAGEMENT

• competition for water allocations can result in local, national or regional geopolitical conflicts, particularly in areas where rivers cross state or national borders

• in areas heavily affected by drought even allocation schemes are insufficient to preserve water supplies, particularly in the context of climate change such as in Cape Town in 2020 where water supplies ran out due to extreme drought

• building on floodplains may still occur if there is population and land pressure

• monitoring and enforcement of abstraction licenses can be difficult