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Assessments of water resources and their management

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Context - Water is essential for life, but humanity faces complex challenges related to increasing demand, variability of supply, widespread pollution and water-related disasters.

This is a faithful synthesis and summary of several scientific consensus reports. For the full list of sources, see the references.

Latest update: 31 March 2021


Water is essential for life, but humanity faces complex challenges associated with increased demand, variable supply, widespread pollution, and water-related disasters. It drives economic growth, supports healthy ecosystems, and is essential and fundamental for life itself1. Water resources, their management and any degradation are important to land resource components and effects of land degradation on water quantity and quality should be assessed in more depth in areas where this is reported to be a critical issue2.

1. What are the resources of water available?

About 97% of the water on the Earth is salt water and only 3 % is fresh water; with slightly over 2/3 of this is frozen in glaciers and polar ice caps. The remaining unfrozen freshwater is found mainly as groundwater, with only a small fraction present above ground or in the air. The only natural input to any surface water system is precipitation within its watershed, the total quantity of water in that system at any given time is also dependent on many other factors.

Storage capacity include lakes, wetlands and artificial revservoirs, the permeability of the soil beneath these storage bodies, the runoff characteristics of the land in the watershed, the timing of the precipitation and local evaporation rates. All of these factors also affect the proportions of water loss. Water reclamation or wastewater reuse is the process of co-use instead of single use of freshwater supplies which can be a water-saving measure. When used, water is eventually discharged back into natural water sources where it can still have benefits to ecosystems, improving streamflow, nourishing plant life and recharging aquifers and the natural water cycle can reconvert wastewater into water that can be reused for other purposes3.

2. What is of particular concern regarding water resources?

Estimates indicate that 40% of the world population live in water scarce areas, and approximately ¼ of world’s Gross Domstic Product (GDP) is exposed to this challenge. By 2025, about 1.8 billion people will be living in regions or countries with absolute water scarcity.

Gaps in access to water supply and sanitation, growing populations, more water-intensive patterns of growth, increasing rainfall variability, and pollution are combining in many places to make water one of the greatest risks to economic progress, poverty eradication and sustainable development.

As underlined by the World Bank4, lack of access to water supply and sanitation (WSS) constitutes a public health, economic, and environmental emergency across the developing world. The consequences of such stress are local, national, transboundary, regional, and global in today’s interconnected and rapidly changing world. Consequences will be disproportionately felt by the poorest and most vulnerable.

Regarding the availability of water resources, of particular concern are:

  • The effective use of rainwater
  • The reduced water quality through pollution, salinization and overexploitation by domestic, agricultural, forest and industrial uses;
  • The reduced water quantity / availability because of drought or over-exploitation of water sources;
  • The maintenance of the hydrological regime;
  • The extent and performance of water resources management.

Climate change and population growth are expected to put additional pressure on water resources.

3. How evolve water scarcity over time?

With a global population still growing fast, estimates show that with current practices, the world will face a 40% shortfall between forecast demand and available supply of water by 2030

The World Economic Forum listed droughts, lack of rainfall, or pollution as a cause of water scarcity and one of the largest global risks in terms of potential impact over the next decade.

More than 90% of water in water-scarce regions goes today to irrigated agriculture, but this phenomenon has a long history. Water withdrawal can also be very high for certain industries, but consumption is generally much lower than that of agriculture. The major industrial users include hydroelecric dams, thermoelectric power plants for cooling, as solvent in manufacturing plants, in ore and oil refineries, in chemical processes and in natural gas extraction from shale rock.

Many pollutants also threaten water supplies, but the most widespread, especially in developing countries, is the discharge of raw sewage into natural waters which is also prevalent in quasi-developed countries such as China, India, Nepal and Iran.

4. How critical is water sanitation in this context?

Poor water sanitation and contaminated water are linked to transmission of diseases such as cholera, dysentery, hepatitis A, and typhoid.

Smart investments in clean water and sanitation would prevent needless deaths, and transform lives. Healthier children would become healthier adults who contribute more to the economy. To deliver on their commitment to Sustainable Developments Goal (SDG) 6.2 – “Achieving access to adequate and equitable sanitation and hygiene for all by 2030”5, political commitment and leadership, technological innovations, and breakthroughs in service delivery and financing models are thus all needed. Furher, investing in sanitation is also critical to economic growth and the environment.

In the context of the COVID-19 crisis, the Water Convention and the Protocol on Water and Health jointly serviced by WHO-Europe and UNECE help countries by promoting the availability of safe water for all within countries and across borders and sectors.

5. What is the specific impact of climate change on water resources?

Climate change expresses itself through water as 9 out of 10 natural disasters are water-related andthese water-related climate risks cascade through food, energy, urban and environmental systems. Climate change will worsen the situation by altering hydrological cycles, making water more unpredictable and increasing the frequency and intensity of floods and droughts. These pose, among others, constraints to the rural poor, highly dependent on rainfall variability for subsistence. To achieve climate and development goals, water must thus be at the core of climate change adaptation strategies.

To guide effective such climate change adaptation, activities should reflect the importance of water management for reducing vulnerability and building climate resilience, prioritizing the following actions:

  • Expand beyond traditional integrated water resources management (IWRM); Promote investment and solutions that incorporate management of ‘natural infrastructure’ from the ecosystem services provided by healthy watersheds and coasts;
  • Support actions at scale to build climate resilience by combining watershed management, sustainable infrastructure, and empowerment and learning through adaptive institutions.

6. What is the specific impact of climate change on water resources?

Climate change has made the water cycle far less predictable6. It is radically altering the water cycle as the world is becoming hotter, stormier, wetter, drier and more polluted as higher temperatures are intensifying the growth of dissolved nutrients in bodies of water, leading to harmful algal blooms, dead zones, and fish kills.

Ensuring a sufficient and constant supply of water under increasing scarcity requires :

  • Optimizing the use of water through better planning and incentives; Expanding water supply and availability where and if appropriate;
  • “Water proofing” economies to limit the impact of extremes and uncertainties by better urban planning, expanding crop insurance to protect farmer, and citizen engagement

The World Bank works thus to promote more sustainable management and use of water resources through improvements in water governance. Also, according to the WHO/UNICEF, Safely Managed Water, Sanitation, and Hygiene (WASH) services should enable in particular more frequent and regular hand hygiene by improving facilities and using proven behavior change techniques, which is critical in the COVID19 pandemia context.

7. What is the impact of water resources on economy?

Water supply and sanitation require a huge amount of capital investment in infrastructure such as pipe networks, pumping stations and water treatment works and to replace aging water infrastructure. Some regions could see their growth rates decline by as much as 6 % of GDP by 2050 as a result of water-related losses in agriculture, industrial production, health, income and prosperity.

The world needs thus a fundamental shift in how it understands, values and manages water resources by:

  • Understanding water resources to make evidence-based decisions about water using strengthened water data;
  • Valuing water resources by recognizing the values that societies accord to water and its uses;
  • Managing water resources by pursuing integrated approaches to their management across local, national, and regional levels.

8. How to sustain water resources?

Sustaining water resources means improving resource management at the river basin, country, and transboundary levels. The fragmentation of this resource also constrains water which account for 60% of the global freshwater flow with 2 billion people worldwide dependent on groundwater.

Fragmentation at the national scale, means that cooperation is needed to achieve optimal water resources management and development solutions for all riparians. To deal with these systemic complex and interlinked water challenges, countries will need to improve the way they manage their water resources and associated services.

To better allocate, regulate, and conserve water resources and (natural and man-made) infrastructure development, institutional tools strengthening, information management, such as legal and regulatory frameworks, water pricing, and incentives are thus needed.

Investments in innovative technologies and information systems and the rapid dissemination and appropriate adaptation or application of these advances will be a key to strengthening the global water security and needed for resource monitoring, decision making under uncertainty, systems analyses and hydro-meteorological forecast, warning and developing non-conventional water sources.

9. What is the specific contribution of the World Bank in the management of this climate/water resources context?

The World Bank contributes to ensure that water benefits are equitably and sustainably accessible to all. through the removal of structural barriers that prevent access to water resources and services and that limit participation in water institutions and processes. It provides knowledge, advocacy, technical expertise, and financial support to strengthen water services and institutions around the world7.

Its 2030 Water Resources Group (WRG)8 forges multi-stakeholder partnerships to collectively manage scarce water resources and to leverage the power of appropriate technologies so that possible solutions can be rapidly rolled out to meet the scale of the challenge.

In this context, they work with their clients to improve water management, providing investment and technical support that builds resilience, reduces emissions, and lowers costs. The World Bank also work to reform institutions and processes so that they become more inclusive and accountable to citizens, reflect greater diversity in their management and staff, and extend services to all.

10. What about water resources more specifcally in agriculture?

Water in agriculture is central to feeding the planet, providing livelihoods, and building resilience to climate shocks and extremes. It takes around 2,000 – 3,000 litres of water to produce enough food to satisfy one person's daily dietary need9.

Irrigation methods such as furrow and overhead sprinkler irrigation are usually less expensive but are also typically less efficient, because much of the water evaporates, runs off or drains below the root zone. Other irrigation methods considered to be more efficient include drip or trickle irrigation, surge irrigation, and some types of sprinkler systems where the sprinklers are operated near ground level10.

In their support to the Coronavirus (COVID-19) response and recovery the Water Group of the World Bank11 works to ensure continuity of irrigation services that sustain critical agricultural production and provide cash injections to rural communities, create job opportunities for the vulnerable, and improve the productivity of agro-environmental assets to build long-term resilience to shocks.

11. What are the Source Protection Explorer and the Protecting Water Atlas?

The Source Protection Explorer of the World Bank enables users to explore cities that can meet specified pollution reduction targets using conservation actions and the area and cost required to reach these targets. The Protecting Water Atlas12, where users can explore data and analyses that underpin The Nature Conservancy's global-scale reports. This mapping site is part of a family of spatial decision tools while the Water Scarcity Explorer enables users to look at how, where and when water has been used and explore potential strategies to alleviate scarcity within a given basin.

Further, a Natural Solutions Toolkit13 puts scientific information in the hands of public agencies, communities and key stakeholders and includes spatial decision tools and web applications to catalyze water conservation.

12. What is the Dynamic Water Resources Tool?

The Dynamic Water Resources Assessment Tool (DWAT)14 as a part of the activities of World Meteorological Organization (WMO) is designed to assist long-term planning and policy assessment and development by allowing the assessment of land-use changes over time, and of the impacts on water availability under a wide variety of scenarios, including climate change.

This tool is intended to help users to identify current and future water management challenges and compare those with current and past water resources availability.

Being peer-reviewed by a panel of Commission for Hydrology experts, its use can contribute to water reform by providing nationally and regionally consistent water resources information and data, and aid in the formulation of government policy and the development of broad-scale strategic plans and decision making.

13. What is the role of UNICE (United Nations Economic Commission for Europe) in the management of water resources?

The working groups of UNICE on "Integrated Water Resources Management” (IWRM) and on “Monitoring and Assessment” activities aim to promote and ecosystem approach, prevent, control and reduce transboundary impacts, and an equitable and reasonable utilization of transboundary waters by ensuring conservation and, where necessary, restoration of water-related ecosystems They also work to build and strengthing the institutions responsible for the management of transboundary waters. and promote access to information and public participation in decision-making. Further goals are detailed in the Level 2 of these Highlights.

14. What are the contributions of the United Nations to water resources assessments programmes?

The United Nations World Water Development (WWDR), coordinated by the World Water Assessment Programme (WWAP), in its 2021 report entitled ‘Valuing Water'15 groups current methodologies and approaches to the valuation of water into five interrelated perspectives: valuing water sources, their infrastructure for water storage, use, reuse or supply augmentation, the drinking water, sanitation and related human health water services, its input to production and socio-economic activities and other socio-cultural values including recreational, cultural and spiritual attributes.

These are complemented with experiences from different global regions; opportunities to reconcile multiple values of water through more integrated and holistic approaches to governance, to financing; and methods to address knowledge, research and capacity needs.

The primary goal of the 'Water for Life' Decade 2005-201516 through its inter-agency coordination mechanism UN-Water, focused on furthering cooperation at all levels, in particular action-oriented activities and policies, so that the water-related goals of the various international agreements in this area could be achieved in terms of both quantity and quality, and include measures to improve sanitation. Achieving the goals required sustained commitment, cooperation and investment on the part of all stakeholders from 2005 to 2015 and far beyond.

The objectives for the International Decade for Action on Water for Sustainable Development, 2018-202817 have been defined as advance sustainable development, energizing implementation of existing programmes and projects and mobilize action to achieve the 2030 Agenda for Sustainable Development18.

A series of reports of international organizations including The World Bank, the United Nations or the World Meteorological Organization which are mentioned in the text.

1  and 
9  UN Water – Coping with Water Scarcity 2007
12 The Protecting Water Atlas ; The World Bank 
13 Natural Solutions Toolkit  

Themes covered
Publications A-Z

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