Nature is teaching … are we learning?
The three major challenges in the water sector can be summed up as too little, too much or too dirty. Water use over the last century has been growing by more than twice the rate of population increase. A central challenge for sustainable development is how to balance the competing uses of water; ensure that the needs of all are met – especially the poor and marginalised – and that the health and diversity of ecosystems are maintained.
By 2050, 70% of the world’s population will live in urban areas, putting pressure on river basins to balance the needs of humans and ecosystems. In many cases, urbanization, economic development, climate change and the need to produce more food for a growing population are limiting water availability. So how are we supposed to overcome these challenges?
Traditionally, we have approached this by manipulating our environment, building ‘grey’ infrastructure to manage the needs and impacts of human populations. We have cleared forests for agriculture and paved land for urbanisation to meet the needs of an exponentially increasing population without seriously considering the environmental consequences. We have laid pipelines, diverted rivers, erected dams, dried up aquifers, flooded valleys, and polluted waterways all to meet water demand.
The road to improved water management does not, however, have to be paved in concrete alone. For millennia nature has developed, tested and perfected natural ‘technologies’, this ‘green infrastructure’ can be adopted, adapted or combined with grey infrastructure to provide more environmentally sensitive and sustainable water solutions. Investing in natural solutions can reduce costs while being an effective means of improving water security.
A fundamental scientific principle we should be accommodating in all our planning is the carrying capacity of an ecosystem – the population that can be supported indefinitely by the available resources and services of an ecosystem without degrading that ecosystem. Basically, living within the limits of resources and services that an ecosystem can provide.
In the context of water management, are we nearing the carrying capacity of our available resources? This depends on three factors: the water resources available in the ecosystem, the size of the population and the water resources each individual is consuming.
As water professionals, population growth is not within our remit, but we can impact the water resources available to us, and how much water is consumed. The volume of water available to us in the ecosystem is dependent on accessibility and quality. The planet’s accessible water is limited and is further reduced by poor water quality. Nature can assist in both areas.
Source Water Protection Strategies
Ecosystem degradation is a major cause of increasing water-related risks and extreme water events, as it reduces the ability of an ecosystem to fully perform its ecosystem services. Forests, wetlands, rivers, aquifers and soils all play a significant role in the water cycle. When these systems become polluted or degraded they are unable to maximise storage, and water will not be fit for human use. Strategies such as forest protection, reforestation and the use of cover crops can help reduce sediment and nutrient pollution. This can in turn reduce the cost of water treatment.
Wetlands support the regulation of water quality by reducing sediment loadings, capturing and retaining pollutants, and recycling nutrients. Where water becomes polluted, both constructed and natural ecosystems can help improve water quality.Wetlands are also used within urban environments to mitigate the impact of polluted stormwater runoff and wastewater. Both natural and constructed wetlands biodegrade or immobilize a range of emerging pollutants, including certain pharmaceuticals, often performing better than grey solutions. For water storage, natural wetlands, soil moisture and more efficient recharge of groundwater could be more sustainable and cost-effective than infrastructure such as dams.
By 2050 global water demand is expected to increase by a third. In an effort to meet current demand we have over-abstracted from rivers and aquifers, built dams and pipeline networks , and resorted to desalination with negative impacts on coastal ecosystems. For far too long we have tried to solve our water problems only with grey infrastructure, ignoring the silent stakeholder – nature. It’s time to change.
Green infrastructure uses natural or semi-natural systems to provide benefits that are equivalent or similar to conventional grey infrastructure. Urban green infrastructure, including green buildings, is an emerging trend that is establishing new benchmarks and technical standards that embrace many nature-based solutions. Prompted by a compelling business case, business and industry are increasingly promoting nature-based solutions to improve water security for their operations. Combining green and grey infrastructure approaches can lead to cost savings and greatly improved overall risk reduction. Urban green infrastructure can yield positive results in terms of water availability, water quality, and flood and drought reduction.
Improved agricultural practices
Agriculture will need to meet projected increases in food demand by improving its water use efficiency, simultaneously reducing its water footprint. ‘Conservation agriculture’, which incorporates practices aimed at minimising soil disturbance, maintaining soil cover and regularising crop rotation, is just one approach to sustainable food production. Agricultural systems that rehabilitate or conserve ecosystem services can be as productive as intensive, high-input systems, but with significantly reduced ecosystem impacts.
In the words of Gilbert F. Houngbo, Chair of UN-Water, “For too long, the world has turned first to human-built, or “grey”, infrastructure to improve water management. In so doing, it has often brushed aside traditional and indigenous knowledge that embraces greener approaches. Three years into the 2030 Agenda for Sustainable Development, it is time for us to re-examine nature-based solutions to help achieve water management objectives”.
We don’t need to choose one or the other. It’s not a boxing match between green technologies and grey infrastructure. It’s about finding a balance between them, for each individual situation. We are capable of solving our water challenges, we just need to ensure that our approaches work with nature not against it.
Nature is Teaching…..are we ready to learn?