Water management is health management

Withclimate change accelerating and its effects exacerbating othergeopolitical and development crises, the role of environmentalprotection in preserving and improving human well-being has becomestarkly apparent. This recognition lies at the heart of the concept of“planetary health,” which focuses on the health of human civilisationand the condition of the natural systems on which it depends.Theconcept’s logic is simple: if we try to deliver better health to agrowing population, without regard for the health and security of ournatural resources, we will not just struggle to make new strides; wewill reverse the progress already made. Where things get complicated isin applying the concept, particularly when addressing the nexus of waterservices, health, and ecosystem integrity.Since at least 1854, whenJohn Snow discovered that cholera was spread through contaminated watersupplies in central London, humans have understood that polluted wateris bad for our health. The degradation of freshwater ecosystems oftenbrings disease, just as the protection or strengthening of suchecosystems improves health outcomes.But, while it is now wellunderstood that progress in one area improves outcomes in another, suchco-beneficial dynamics often are insufficient to spur investment in bothareas.For example, investing to protect a watershed can alsoprotect biodiversity and improve water quality in associated rivers,thereby benefiting human health. But if the goal is explicitly toimprove human health, it might be more cost-effective simply to investin a water-treatment plant.A more compelling dynamic iscomplementarity: when investment in one area increases the returns oninvestment in other areas. In this scenario, investments in protecting awatershed would aim not just to produce returns directly, but also toboost the returns of simultaneous investments in human health.Complementarity produces mutually reinforcing dynamics that improveoutcomes across the board.A well-functioning water sector alreadyattempts to balance complementary interventions. Indeed, such a systemamounts to a multidisciplinary triumph of human ingenuity andco-operation – involving engineering, hydrology, governance, and urbanplanning – with far-reaching complementary impacts on both human healthand economic development.In 1933, through the Tennessee ValleyAuthority Act, the United States established an agency whose purpose wasto build hydroelectric dams on the Tennessee River. That effortbenefited industry, agriculture, flood control, and conservationthroughout the Tennessee Valley watershed, until then one of thecountry’s most disadvantaged regions.Since then, governmentsworldwide have recognised the potential of water infrastructure tocomplement other economic and social policies, including those intendedto improve health outcomes. It is no coincidence that one of the WorldBank’s largest lending portfolios – $35bn worth of investments –comprises water projects.But understanding the potential ofcomplementarity is just the first step. To maximise results, we mustdesign a coherent strategy that takes full advantage of the dynamic, atthe lowest possible cost. The question is whether there is an optimalmix of environmental protection and direct health interventions on whichpolicymakers can rely to maximise investment returns for both.Arecent analysis suggests that, in rural areas, a 30% increase inupstream tree cover produces a 4% reduction in the probability ofdiarrhoeal disease in children – a result comparable to investing in animproved sanitation facility. But, if that is true, we have yet todetermine at what point reforestation becomes a better investment thanimproving sanitation, let alone increases the returns of other healthinterventions by the highest possible amount.Another study foundthat an estimated 42% of the global malaria burden, including ahalf-million deaths annually, could be eliminated through policiesfocused on issues like land use, deforestation, water resourcemanagement, and settlement siting. But the study didn’t cover thepotential benefits of employing insecticide-treated nets as a tool forfighting malaria, ruling out a comparison of the two investments’returns.Worldwide, around 40% of cities’ source watersheds show highto moderate levels of degradation. Sediment from agricultural and othersources increases the cost of water treatment, while loss of naturalvegetation and land degradation can change water-flow patterns. All ofthis can adversely affect supply, thereby increasing the need to storewater in containers – such as drums, tanks, and concrete jars – thatserve as mosquito larval habitats. Can we show that ecologicalrestoration of the watershed could do more than just insecticides ormosquito nets to support efforts to reduce malaria (and dengue) incities?In all of these cases, finding the best option requiresknowing not just the relative contribution of different interventions,but understanding their complementarity. In a world of limitedresources, policymakers must prioritise their investments, including bydifferentiating the necessary from the desirable. To that end, findingways to identify and maximise complementarity is vital.Some 2.1bnpeople worldwide lack access to safe, readily available water at home,and more than twice as many – a whopping 4.5bn – lack safely managedsanitation, severely undermining health outcomes and fuelling riverpollution. With a growing share of the world’s population – includingmany of the same people – feeling the effects of environmentaldegradation and climate change firsthand, finding solutions thatsimultaneously advance environmental protection, water provision, andhealth could not be more important. Global health and conservationprofessionals must co-operate more closely to find those solutions – andconvince policymakers to pursue them. – Project Syndicate* Giulio Boccaletti is Chief Strategy Officer and Global Managing Director for Water at The Nature Conservancy.