Picture: Wynand van Poortvliet/Unpslash
1 Allowing rivers to flow more naturally
Water management for power generation, flood risk reduction, or to store and deliver water for agricultural, industrial or domestic uses, changes the quantity, timing and variability of flows and levels.
This contributes substantially to loss of freshwater biodiversity.
Maintaining or restoring ecologically important attributes of hydrological regimes improves biodiversity outcomes.
The science and practice of environmental flow assessment enables identification and quantification of these attributes.
Environmental flows have already been incorporated into policies in many places and examples of environmental flow implementation from a range of contexts have been documented.
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2 Reducing pollution
Many pollutants affect freshwater ecosystems, including nutrients from sewage, fertilisers or animal waste; synthetic chemicals; pharmaceuticals; plastics and sediments mobilised by agriculture, forestry and mining.
Management responses include improved wastewater treatment, regulation of polluting industries, improved agricultural practices and nature-based solutions such as the restoration of floodplain wetlands. Evidence is needed on sources, pathways and impacts of some pollutants, including microplastics and pharmaceuticals, to inform policy and management.
3 Protecting critical wetland habitats
An estimated 30% of natural inland wetlands have disappeared since 1970.
Causes include land conversion to agriculture and reduced hydrological connectivity after the uilding of dams and levees.
Climate change can also alter the distribution and extent of wetlands, while forestry, mining and urbanisation have affected freshwater habitats downstream.
Community conservation of habitats, the designation of formal protected areas, land-use planning and habitat restoration programmes can all support habitat protection.
Systematic freshwater conservation planning tools, which take account of hydrological factors, can help prioritise freshwater habitats for efficient conservation and restoration investments.
4 Ending overfishing and unsustainable sand mining
The exploitation of living organisms and minerals affects freshwater biodiversity through the removal of individuals and their habitats and, indirectly, through alterations to freshwater ecosystems. A wide range of freshwater life forms are exploited, including plants, invertebrates (such as crabs), fish, amphibians, reptiles (including turtles and their eggs), water birds and mammals (such as otters).
The 2016 Rome Declaration, convened by the UN Food and Agriculture Organisation, describes steps needed for sustainable freshwater fisheries.
Extraction of riverine minerals, especially sand and gravel for use in construction, is increasing rapidly in many regions. Solutions can include reducing demand for construction materials (eg through improved design), substituting new concrete with recycled materials and improved supply chain standards.
5 Controlling invasive species
Freshwater habitats are especially susceptible to invasive non-native species and impacts range from behavioural shifts of native species to the restructuring of food webs and the extinction of entire faunas.
The economic costs are also significant, reaching billions of dollars in the US alone.
Preventing the introduction of non-native species is the best way of limiting their impacts. A few countries have taken steps to identify and prioritise these species for action. In the US, invasive species advisory councils bring together regulators, researchers and stakeholders to address research, policy and management needs related to non-native species.
6 Safeguarding and restoring connectivity
Many freshwater species depend on connectivity between upstream and downstream river reaches, or between river channels and floodplain habitats, for their migration and reproduction.
Dams and weirs fragment upstream-to-downstream connectivity and, through flow alterations, also affect river-to-floodplain, surface-to-groundwater and season-to-season connectivity.
Coherent planning for energy and water, including strategic siting of new infrastructure and consideration of alternative options, can balance connectivity maintenance with hydropower generation or water storage.
Removal of obsolete dams can restore connectivity in degraded ecosystems. Removal or repositioning of levees can improve river-to-floodplain connectivity, while enhancing water storage and/or conveyance on floodplains as part of flood-risk management strategies.
The Emergency Recovery Plan is rooted in practical actions that have already been implemented somewhere in the world. The challenge now is to move from ad hoc freshwater conservation and restoration successes to a strategic approach that achieves results at a far larger scale.