Water Supply Engineering: Introduction
Lecture - 01
Water
✓ Water is essential for all forms of life.
✓ Used for:
• Drinking
• Cooking and food preparation
• Sanitation and hygiene
• Irrigation and agriculture
• Industrial and manufacturing processes
• Energy production (e.g., hydroelectric power)
Availability of Water on Earth
• 71% of Earth’s surface is covered by water.
• Only 2.5% of the total water is freshwater.
• Less than 1% of freshwater is accessible (in rivers, lakes, shallow
groundwater).
Global Water Distribution and Scarcity
• Freshwater resources are unevenly distributed.
• Many regions face seasonal or chronic water shortages.
• More than 2.2 billion people worldwide lack safely managed drinking
water.
Major Challenges in Water Supply
• Scarcity of freshwater due to:
o Climate change
o Overuse of groundwater
o Uneven distribution
• Pollution from industrial, agricultural, and domestic sources
• Rapid urbanization and increasing demand
• Aging or inadequate infrastructure
• Poor water management practices
Water Use by Sector
• Agriculture: ~70% of global freshwater use
• Industry: ~20%
• Domestic use: ~10%
Solutions to Water Challenges
• Integrated Water Resources Management (IWRM)
• Investment in water infrastructure and sanitation
• Protection of water sources
• Public awareness and conservation practices
• International cooperation and policy reform
Key Points
• Water is vital but limited and under threat.
• Safe and equitable access to water is a major global issue.
• Sustainable management of water resources is essential for future
development.
References
• UN-Water. (2023). Water Facts. Retrieved from https://www.unwater.org
• WHO & UNICEF. (2023). Progress on household drinking water, sanitation
and hygiene 2000–2022. Retrieved from https://washdata.org
• FAO. (2021). The State of the World's Land and Water Resources for Food
and Agriculture. Retrieved from https://www.fao.org
Water Facts [United Nations, UN Water]
• 2.2 billion people (1 in 4) still live without safely managed drinking
water, including 115 million people who drink surface water.
(WHO/UNICEF, 2023).
• 3.5 billion people (4 in 10) still live without safely managed
sanitation, including 419 million who practice open defecation.
(WHO/UNICEF, 2023).
• 2 billion people still lack basic hygiene services, including 653 million
with no facility at all. (WHO/UNICEF, 2023).
• Around 1,000 daily deaths of children under five are due to unsafe
water, sanitation and hygiene. (WHO, 2023)
• Children under the age of 15 living in countries affected by protracted
conflict are, on average, almost three times more likely to die from
diarrhoeal diseases caused by a lack of safe water, sanitation and
hygiene than by direct violence. (UNICEF, 2019)
• More than 2 billion people live in countries under water stress and 3.6
billion face inadequate access to water at least one month per year.
(WMO, 2021)
• Water-related disasters account for 70% of all disaster related deaths.
(World Bank Group, 2022)
• Since 2000, flood-related disasters have increased by 134%. (WMO,
2021)
• In 2023, glaciers lost more than 600 gigatons of water, the largest mass
loss registered in the last five decades. (WMO, 2024)
• Only 0.5% of water on Earth is useable and available freshwater.
(WMO, 2021)
• To meet SDG 6, progress needs to increase, on average, by 6x for
safely managed drinking water, 5x for safely managed sanitation and
3x for basic hygiene. (WHO/UNICEF, 2023)
• 72% of all freshwater withdrawals are used by agriculture, 16% by
industries, and 12% by municipalities. (FAO, 2023)
• Global water demand is projected to increase by 20 to 30% by 2050.
(UN, 2018)
• To produce a person’s daily food, it takes 2,000-5,000 litres of water.
A 50% increase in food demand is expected by 2050. (FAO, 2020)
• Water-use efficiency has increased by 19.3% globally from 2015 to
2021, but around 58% of countries still exhibit low water-use
efficiency. (FAO, 2024)
• The world will not achieve sustainable water management until
2049. (UNEP, 2024)
• Only 27% of industrial wastewater is safely treated. (UN-Habitat,
WHO, 2024)
• 42% of household wastewater is not safely treated. (UN-Habitat,
WHO, 2024)
• Only 56% of monitored water bodies in 120 reporting countries are in
“good ambient water quality”. (UNEP, 2024)
• Just 43 out of 153 countries sharing transboundary waters have
operational arrangements covering 90% or more of their shared water
bodies. (UNECE, UNESCO, 2024)
• Every US$ 1 invested in water and sanitation yields a return of US$
4.3. (UN-Water GLAAS, 2014)
• Aid for water and sanitation decreased by 5% between 2015 and
2022. (UN-Water GLAAS, 2022).
• Estimates indicate that to achieve SDG 6, over US$1 trillion will be
needed per year. (World Resources Institute, 2020).
SDG
Goal 6: Ensure availability and sustainable management of water
and sanitation for all
Target 6.1:
Achieve universal and equitable access to safe and affordable drinking water for all
• Indicator 6.1.1: Proportion of population using safely managed drinking water
services
• Definition:
o Safely managed = Water from an improved source (piped water,
boreholes, protected wells) that is:
▪ Accessible on premises.
▪ Available when needed.
▪ Free from contamination (E. coli, arsenic, fluoride, etc.).
Target 6.2:
Achieve access to adequate and equitable sanitation and hygiene for all and end open
defecation, paying special attention to the needs of women and girls and those in
vulnerable situations
• Indicator 6.2.1: Proportion of population using (a) safely managed
sanitation services and (b) a hand-washing facility with soap and water
• Definition:
o Safely managed sanitation = Improved toilets (sewers, septic tanks)
that:
▪ Are not shared.
▪ Treat/dispose waste safely.
o Basic handwashing = Soap and water available at home.
Target 6.3:
Improve water quality by reducing pollution, eliminating dumping and minimizing
release of hazardous chemicals and materials, halving the proportion of untreated
wastewater and substantially increasing recycling and safe reuse globally
• Indicator 6.3.1: Proportion of domestic and industrial wastewater flows
safely treated
• Definition:
o Domestic + industrial wastewater treated to meet standards.
• Measurement:
o National wastewater treatment reports.
• Challenges:
o High costs of treatment plants.
• Indicator 6.3.2: Proportion of bodies of water with good ambient water
quality
• Definition:
o Rivers/lakes with low pollutants.
• Measurement:
o Water quality monitoring stations.
• Challenges:
o Agricultural runoff (fertilizers, pesticides).
Target 6.4:
Substantially increase water-use efficiency across all sectors and ensure sustainable
withdrawals and supply of freshwater to address water scarcity and substantially
reduce the number of people suffering from water scarcity
• Indicator 6.4.1: Change in water-use efficiency over time
• Definition:
o GDP per unit of water used (economic efficiency).
• Measurement:
o National water withdrawal vs. economic output data.
• Indicator 6.4.2: Level of water stress: freshwater withdrawal as a
proportion of available freshwater resources
• Definition:
o Freshwater withdrawn as % of available supply.
o High stress = >70% withdrawal (e.g., Middle East, India).
• Challenges:
o Overuse in agriculture (70% global withdrawals).
Target 6.5:
Implement integrated water resources management at all levels, including through
transboundary cooperation as appropriate
• Indicator 6.5.1: Degree of integrated water resources management
• Definition:
o Policies, funding, and stakeholder involvement in water management.
• Measurement:
o UNEP surveys scoring countries (0–100).
• Indicator 6.5.2: Proportion of transboundary basin area with an operational
arrangement for water cooperation
• Definition:
o % of shared river/lake basins with joint management agreements.
• Challenges:
o Political conflicts over water (e.g., Nile River disputes).
Target 6.6:
Protect and restore water-related ecosystems, including mountains, forests,
wetlands, rivers, aquifers and lakes
• Indicator 6.6.1: Change in the extent of water-related ecosystems over time
• Definition:
o Satellite tracking of wetlands, mangroves, etc.
• Measurement:
o UNEP’s Global Wetland Outlook.
• Challenges:
o Wetlands lost 3x faster than forests.
Target 6.a:
Expand international cooperation and capacity-building support to developing
countries in water- and sanitation-related activities and programmes, including water
harvesting, desalination, water efficiency, wastewater treatment, recycling and reuse
technologies
• Indicator 6.a.1: Amount of water- and sanitation-related official
development assistance that is part of a government-coordinated spending
plan
• Definition:
o Funds for water projects aligned with national plans.
• Challenges:
o Funding gaps (estimated $114B/year needed).
Target 6.b:
Support and strengthen the participation of local communities in improving water
and sanitation management
• Indicator 6.b.1: Proportion of local administrative units with established
and operational policies and procedures for participation of local communities
in water and sanitation management
• Definition:
o % of villages/towns involving citizens in decisions.
• Challenges:
o Lack of grassroots governance.
Key Global Challenges for SDG 6:
• 2.2 billion lack safe drinking water (WHO, 2023).
• 3.5 billion lack safe sanitation (UNICEF, 2022).
• 80% of wastewater is untreated (UN Water).
Assignment:
Prepare a Report on ‘SDG 6 in Bangladesh: Current Status, Key Challenges, and
Pathways to Ensure Clean Water and Sanitation for All’.
