Safe Water Supplies Begin with Healthy Watersheds

Contributors: Brett Gleitsmann (Conrad N. Hilton Foundation) and Jason Lopez (Millennium Water Alliance)

Expanding water coverage to un- or under-served communities while ensuring that existing sources are safe, functioning and continuous is a fundamental development objective of our time. But less reliable and manageable water supplies — driven by deteriorating environmental and climatic conditions — threaten our ability to do so. Water security increasingly depends on considering water within its wider hydrological and governance context, from source protection upstream to system management downstream.

Water stress and insecurity are rising globally. Many countries are now forced to grapple with water challenges on multiple fronts, including mounting water scarcity, more frequent droughts, worsening floods, and record-breaking temperatures. Universal access to water and sanitation services also remains beyond reach, especially in low-income countries where poverty and vulnerability are most acute.

One in three people — over 2.2 billion people — still do not have access to safe drinking water, while more than half the global population lacks adequate sanitation services. Rural communities are lagging behind their urban counterparts, with many experiencing water shortages for at least one month of the year — a danger expected to grow exponentially by 2050. At the same time, droughts have increased by 29% since 2000 and flooding disasters by 134%, even damaging vital water infrastructure.

When water flows are stable and consistent, freshwater springs and communal water points are critical lifelines, especially in hard-to-reach areas and regions where rain is highly seasonal or chronically sparse. Yet, many springs, wells and boreholes are seeing reduced yields, dropping volumes, and low functionality. Water points and systems that once could be relied on are failing. In parts of sub-Saharan Africa as many as 70% of rural water schemes have become fully or intermittently non-functional. Although often triggered by poor construction, operation, and maintenance, the situation is being exacerbated by growing instances of water sources running dry. When this occurs, people are forced to rely on unprotected sources, with grave consequences on health and wellbeing, especially for children.

The continuity of water — known as water source sustainability — is an increasingly pressing issue but one that has received insufficient attention, especially in the Water, Sanitation, and Hygiene (WASH) sector. While new water development goes on, the very source waters that feed our water supply systems are becoming ever more degraded or depleted. And without these supplies at origin, there is no safe access.

Countering this impending water crisis requires protecting water where it first originates, better managing water-related hazards and ensuring there’s enough water for human needs as well as for economic and ecological purposes.

Hydrology Disrupted

In the prevailing narrative, access to water is hindered by poor management, a lack of financing and more recently, climate change. In other words, systemic inadequacies and underfunding of water services, more erratic and extreme weather, and surging populations and production driving over-abstraction and competition with household water. However, while there are many factors that challenge water service delivery, a key underlying issue is often not well-captured or discussed — one that hugely affects water source sustainability: the degradation of the natural environment.

Growing human pressures on ecosystems and landscapes are both driving climatic fluctuations and disrupting eco-hydrological processes that provide clean, reliable sources of water. Higher temperatures are increasing evaporation which modifies rain patterns. In many places, this is leading to more irregular and unusually low rainfall, causing longer dry spells, while elsewhere to more intense precipitation, triggering deluge.

What more, vegetation plays a significant role in how rain interacts with landscapes to generate and replenish source waters. Forests, for example, release water into the atmosphere and improve soil filtration capacities.

But human activity is eroding the Earth’s green cover, hugely harming the natural cycling of water. Changes in land cover and use are affecting where water is stored, how it moves and how clean it is. Deforestation, converting grassland into cropland, intensive farming and livestock rearing, and rapid urbanization are all contributing to the problem.

As a result, water flows worldwide are being altered. So much so that rivers have experienced rapid decline and over 50% of global catchment areas now display deviations from normal conditions, with the majority exhibiting drier conditions.

The threat to water services — the points, schemes, and networks that bring water to people — is huge, and the consequences dire, including rising costs for drilling deeper and deeper boreholes or replacing structures that have been lost.

Despite this, the WASH sector has given insufficient consideration to the broader natural systems — the hydrology, catchments, and source waters — that underlie water provision, placing emphasis instead on infrastructural and technical solutions (mainly the extraction, storage, distribution, and treatment of water). But the problem is no longer technological or financial nor climatic alone. We can no longer assume that digging and drilling will result in water. Environmental and climatic shifts are now impeding healthy hydrological functions, creating ever more challenges for water service delivery.

Digging Deeper: How Environmental Degradation Impacts Water Supplies and Undermines Service Delivery

But how, exactly, does environmental degradation — especially watershed degradation — impact water supplies and reduce service levels?

A watershed (or catchment or basin, depending on size) is a land area that drains to the same body of water. It’s an interconnected system: watersheds store, transport, and release water by way of their geological and hydrological characteristics, thereby deeply connecting water sources and supplies to ecological and landscape conditions.

When healthy, watersheds provide many valuable services we often take for granted, including clean water, fertile soils, erosion control, flood protection and nutrient movement. Watersheds also support good physical and chemical water properties. Key aspects of a healthy watershed can include intact headwaters and good vegetation cover.

But when a landscape is disturbed, the ecology of a watershed changes, impacting water’s ebbs and flows and good hydrological functioning. Degraded lands are characterized by barren soils which reduce soil water absorbency and cause greater erosion, runoff, and sedimentation — factors that can significantly damage water supplies and conditions downstream. Surface waters and shallow groundwater — often key sources of domestic water — are particularly vulnerable.

These dynamics impact the three critical aspects of water: quantity, quality and flow regulation:

1) Water Quantity (Availability)

Landscapes help control the cycling of water — essentially, determining what happens to rain when it falls to earth. Under natural conditions, some rainfall runs off the land surface, while most penetrates and moistens soils. It then continues to move downward by gravity beneath the soil through the processes of infiltration and percolation. Rainwater is eventually stored underground in aquifers. Finally, some of the water reemerges on the surface, discharging through seeps, springs and streams. Surface and ground waters are replenished from this rainfall and its runoff.

Infiltration and percolation depend on the amount, duration and intensity of precipitation and on land’s physical characteristics. Vegetated watersheds protect the top layers of soil, better manage rainfall and help ensure consistent supplies of water year-round. In fact, over two-thirds of drinking water worldwide is provided by forested watersheds.

As landscapes are stripped of vegetation, however, these processes are weakened: soils become unstable and unable to soak any or adequate rainfall. This causes rain to gush off the land, generating soil erosion and excess runoff along its path. Runoff, although important to replenishment functions, is escalated by impervious surfaces and, ironically, even too much rain in a short time over a degraded area can impede infiltration. Consequently, the area where natural infiltration occurs is reduced, causing less rain to seep underground. As a result, aquifers are not being recharged, stream flows decrease, and groundwater tables fall. This causes water yields at springs, boreholes and wells to shrink or stop, hindering service levels.

 2) Water Quality

Trees and vegetative cover are also important to water quality. Eroding lands contribute to the formation of sediment which detaches from soils and blends with runoff. Some sedimentation is very natural, but excessive sediment can significantly damage ambient water. Sediment picks up pollutants and other impurities, including nutrients from fertilizers, pesticides, microbes from waste and metals from industrial activity. Runoff from irrigated farmlands, for example, can carry nitrogen and phosphorus, which can eventually lead to depleted oxygen, dead zones and harmful algal blooms in water bodies. Such impurities, along with increased turbidity, result in dirtier water and higher treatment costs. Land and watershed degradation have already impacted drinking water for more than 700 million people, costing cities globally $5.4 billion each year in treatment. Poor land management practices can thus both decay soils on-site and worsen pollutant load downstream.

In contrast, natural ecosystems like forests, grasslands and wetlands act as important buffers against sedimentation. Strong roots anchor soil to the ground while vegetation absorbs sediment, reducing what would otherwise reach streams, rivers and lakes. These ecosystems also filter contaminants, straining and removing them from water. Vegetative barriers help buffer people and infrastructure from dangerous overflows and reduce the debris entering catchment areas. This can cut costs and boost water cleanliness with benefits for household wellbeing.

Of course, water quality is impacted by other factors as well: municipal waste and sewage, improper treatment and disposal of industrial wastewater, inadequate sanitation and hygiene practices and so on. But it is important to also understand how water quality is affected by environmental degradation via sediment transport.

3) Water Flow (Regulation)

Lastly, landscapes also help regulate water flows by controlling how, and how quickly, rainwater is captured and released. Landscapes act as natural sponges: the canopy and roots of trees slow heavy rainfall, allowing it to move onward more gradually. Vegetation helps compact soils, braking excessive stormwater and better controlling how water moves through a landscape. Trees along riparian areas, for example, can reduce the potential and severity of surging events. In so doing, they reduce water’s momentum and, with it, the risk of flooding. Instead, when soils are dry, the detrimental effects of runoff are intensified. Flash floods can directly damage water and sanitation infrastructure while spreading disease and threatening livelihoods and life.

Furthermore, as excess runoff moves silt-laden water downstream, layers of sediment progressively settle on reservoir floors. This sediment can prevent water from flowing smoothly, causes wear and tear, and clogs canals. And rapid sediment buildup can reduce the storage capacity and lifespan of water structures, seriously impacting drinking water supply, irrigation, and hydropower production. Indeed, sediment deposition is escalating the need for reservoir dredging and affecting dam safety worldwide — a risk increasing with more extreme weather.

Advancing Water Security Needs More Holistic Thinking

Although the situation appears dire, there are solutions.

Confronting today’s water challenges requires thinking beyond traditional water infrastructure interventions to how climate change and environmental degradation are impacting source waters — with a vision for long term continuity. This warrants asking: Where does the water for WASH access come from? What are the risks to that water source?

Drinking water services rest on the readiness and reliability of good quality water. A number of factors come to play, including mechanical determinants, financing and social elements, but also geography and hydrology. First and foremost, water services depend on the availability of freshwater and the conditions of the broader catchment where they are found. The loss of natural habitats and deteriorating landscapes are undermining WASH efforts — with significant implications for the sector. Costs are mounting and uncertainty is rising. Notwithstanding, it remains challenging to elevate water resources management (WRM) and the environmental conservation agenda as important aspects of water service delivery.

Healthy watersheds help sustain stable supplies of freshwater and counter water-related shocks. Better managing and rehabilitating landscapes can help preserve source waters and remove stressors while maintaining or reclaiming good watershed functions. This restorative approach — known as watershed management, landscape restoration, or similar terms — involves implementing a range of sustainable land, forest, soil and water conservation measures to revegetate a degraded site and recover soil health. Many measures are nature-based — making them less costly than built infrastructure — and most reflect actions to collect and slow down rainwater while stabilizing soils. This includes planting trees and grasses, terracing croplands and hillsides, and adopting more sustainable (soil-friendly) farming and grazing practices, such as no till, cover cropping and agroforestry.

Whether on cropped or mountain areas, in urban settings or along stream channels, the idea is to apply measures that help decrease erosion, runoff and sedimentation. Doing so can help restore local hydrology and retain cleaner water in the wider catchment. In communities around the world, these kinds of projects have proven to be successful:

• In India’s Uttarakhand state, for example, community-driven spring restoration efforts helped revive 600 freshwater mountain springs, key sources of community drinking water. Digging contour trenches, percolation pits, and ponds helped slow runoff, channel rainwater into the soil and refill the natural springs.
• In Uganda’s Kamwenge District, degraded wetlands were restored back to their original state which helped increase the water-holding and infiltrating capacities of soils and recharged local groundwater reserves.
• In Pembamoto, Tanzania, farmers dug half-moon shaped soil bunds to capture rainwater, thus re-saturating soils, revitalizing the landscape and stopping floodwaters. This practice is also common in the West African Sahel as a strategy for water retention in arid areas. As the land regenerates, on-site soil moisture improves and crops better resist dry conditions. Satellite images have revealed the improvements in vegetation cover over time.

While delivering water benefits, these interventions offer additional co-benefits, including increased agricultural productivity, biodiversity protection and carbon sequestration. As trees grow and soil fertility returns, communities can reap the benefits of better crop yields, local fruit and fodder, and household income — creating material incentives needed to keep investing in watershed health.

Sustainable land and watershed management have been proven to spur water and food security, uphold business operations, create jobs and reduce poverty, with positive impact on livelihoods, nature and climate resilience. And in providing more plentiful, clean, and timely water, improvements in sanitation and health can be expected.

Of course, boreholes, wells and piped networks are not always adequately constructed or managed. This can cause huge problems with reliability and ultimately access, and these issues cannot be downplayed. Poor operation and maintenance reduce water point performance, often causing failure. Infrastructure, technical execution and capital maintenance remain fundamental aspects of water service delivery. But these (the “hardware” issues) are not sufficient now. In many places, the water sources connected to these structures are strained or depleted. This is resulting in unsuccessful drilling rates and diminished functionality, leading to the growing abandonment of water supply schemes.

And even where there is a physical abundance of water, inefficient and inequitable governance can exacerbate water insecurity.

The time has come to think beyond the borehole and upstream of a water scheme to the wider catchment context. Healthy watersheds should be seen as integral elements of a sustainable and resilient water supply system. Doing so means paying attention to catchment dynamics that help provide, filter and regulate water, planning and “proofing” for climate change, and addressing the human drivers of water risk and ecological degradation.

Fortunately, there is growing recognition of the importance of better linking freshwater conservation with WASH through greater regard for water governance issues, climate resilience and environmental health. Interventions in watershed protection alongside more conventional water supply development can also help preserve surface and ground waters for beneficial use, helping safeguard those investments over time. This strengthens the overall water supply context, and — by extension — the context for WASH more broadly.

At the same time, it is vital to enhance the regulations, institutions and capacities of authorities and communities responsible for managing water. Operation and maintenance, reducing leakage, water safety planning, and professionalized service provision have all become increasingly urgent under growing hydrological uncertainty. Water is also a cross-sectoral issue which requires multi-level dialogue, planning and implementation. Integrated WRM approaches can enable a more effective approach to water management, helping ensure resources are used soundly, observing ecological limits and sustainable yield, prioritizing household needs, and enhancing climate-resilient WASH and livelihoods. Fostering context-specific solutions also means ensuring local actors be part of the response. Only this way can we advance systemic change.

These are priority themes in a project in Ethiopia’s Tana Subbasin, led by WRI in partnership with the Millennium Water Alliance, WaterAid, and local government institutions, and funded by the Conrad N. Hilton Foundation. Its key premise: the health of watersheds has a huge impact on water supplies and needs to be considered in water planning and programming.

WRM and WASH cannot succeed in isolation. Investments in water access must account for environmental and climatic factors that increasingly affect source sustainability. Not doing so will undermine long-term WASH efforts. Solutions to systemic inadequacies can be found in strategies, partnerships and funding that help advance more holistic “systems thinking” approaches that look from source to tap. WASH actors should move past conventional methods and step up programming to address water continuity and underlying source water issues. Done well, interventions at the intersection of WRM, WASH and climate adaptation can better advance water security together with environmental, wellbeing and livelihood objectives — forging more resilient water systems and communities.