Water Cycle & Water Insecurity Flashcards
What is a store
- Where water is held, such as the oceans
Fluxes
- measure the rate of flow between the stores
Processes
- Physical mechanisms which drive the fluxes of water between the stores
Explain the order of the hydrological cycle
1) Begins with evaporation where water vapour from the ocean is lifted and condensed in the atmosphere
to form clouds
2) Moisture is then transported around the globe and returns to the surface as precipitation
3) When reaching the ground, some water will evaporate back into the atmosphere whilst some of the
water may percolate the ground to form groundwater
4) The balance of water that remains on the surface of the earth is called runoff and emptied into lakes,
rivers and streams which carry it back to the oceans for the process to start again.
It is therefore a closed system
What is a drainage basin
- The drainage basin is an area of land drained by a river and its tributaries
- Drainage basins are open systems as they have external inputs and outputs that cause the amount of
water in the basin to vary over time. - Drainage basins can be of any size, from that of a small stream possibly without tributaries up to major
international rivers flowing across borders of several countries
What is interception
- Precipitation that does not reach the soil as it is intercepted by vegetation and the forest floor
What is infiltration
- Water on the ground soaking into the soils and porous rocks
What is Through flow
- The flowing of water within the soil, moving towards the river
What is Percolation:
- The movement of water through the soil or underlying porous rock, being stored as groundwater
Explain a Water Budget
- Water Budgets are the balance between precipitation, evaporation and run-off
- Water budgets at a country or regional scale provide a more useful indication of available water supplies – at a local scale they show the annual balance between inputs (precipitation) and outputs (EVT), and how
this can impact on soil water availabilityGraph
- X axis is the months
- First large block (A) shows a water surplus - were precipitation is greater than evapotranspiration
- Second block (B) shows soil water utilisation - evapotranspiration is greater than precipitation - water stored
is being used up by plants - Point C (maximum between B & D) is where the soil moisture has now been used up
- Third block (D), deficiency of soil water as the store is used up and potential evapotranspiration is greater
than precipitation - Final block (E) Soil water recharge where precipitation is greater than potential evapotranspiration and the
soil water starts to fill again
Explain a River Regime
- A regime can be defined as the annual variation in discharge or flow of a river at a particular point
- Much of this river flow is not from immediate precipitation or run-off, but is supplied from groundwater
between period of time, which feeds steadily into the river systems from base water flow - The character of a river regime of the resulting stream is influenced by the size of the river; amount, pattern
and intensity of precipitation; temperature; geology; human activities e.g. dam building;
What are Storm Hydrographs
- Storm hydrographs, show the variation of discharge within a short period of time
- This is normally an individual storm or a group of storms not more than a few days in length
- Before the storm starts the main supply of water to the river or stream is through groundwater or base
flow but, as the storm develops, water comes to the stream by a number of routes - Some water infiltrates into the soil and becomes throughflow, while some flows over the surface as
overland flow.
Explain the two types of storm Hydrograph
Flashy River – short lag time, high peak, steep rising limb
e.g. – caused by intense storm – exceeds infiltration capacity of soil, impermeable rock, low infiltration rate
Flat River – Long lag time, low peak, gently sloping rising limb
e.g. – steady rainfall – less than the infiltration capacity of the soil, permeable rocks, high infiltration rate, larger drainage basins, low population density
What is the significance of a drainage basin
Drainage basins are extremely important in terms of Geopolitical boundaries (determining territorial boundaries), ecology (natural movement of important minerals) and recourse management. The input factors affect the size of importance of the drainage basin through these points.
Explain the four input factors determine the importance of a drainage basin
Climate
- Temperature and precipitation patterns determine availability and vary according to latitude
- Seasonality –Some seasons are wetter than others
- Summer temperatures increase evaporation rates but plant growth increases transpiration rates
Geology
- Determines underground storage according to permeability. Porous rocks store water
- Metamorphic rocks such as granites cause runoff but do not store water
River Systems
- Drainage basins collect precipitation and channels towards the coast
- Availability depends on land use, basin size and shape and precipitation type
- Flow increases downstream, but climate creates variation in discharge and water loss.
Human factors
- Humans disrupt the drainage basin by accelerating processes such as deforestation and changing land
use. By digging deep wells, there is a high risk of salinization which contaminates water sources. - Furthermore, the use of irrigation for extensive cereal farming leads to declining water levels
- Urbanisation increases the proportion of impermeable surfaces which prevents precipitation penetrating
the ground, meaning less groundwater is stored and thus water availability declines
What two output factors effect the importance of a drainage basin
Transpiration
- Biological process by which water is lost from plants through stomata and transferred to the atmosphere
- Transpiration rates depend on the time of year, the type and amount of vegetation cover and the degree
if availability of moisture in the atmosphere
Evaporation
- Evaporation is the physical process by which moisture is lost directly into the atmosphere from water
surfaces and soil. - Evaporation results from the effects of the Sun’s heating and air movement, so rates increase in warm,
windy and dry conditions. - Other factors include the size of the water body, depth of the water, the water quality and type of
vegetation cover (which determines albedo or reflectivity of the surface)
What does El Nino refer to
- Refers to large scale ocean-atmosphere climate interaction linked to periodic warming in sea surface
temperatures across central and east-central equatorial pacific. - High pressure accumulates above Australia, causing droughts like conditions, whilst South America
becomes a low-pressure centre, at high risk of flooding and intense rainfall
What does El Nina refer to
- Represents periods of below-average sea surface temperatures across the east central equatorial pacific.
- Australia has a low-pressure system whilst South America experiences drought like conditions due to high
pressure formation
AUSTRALIA (El Nino case study)
- 2006, Southern Australia had an extremely low rainfall season, the lowest since 1990.
- This caused the River Murray to dry up in places, reducing food production, social wellbeing and water
supply for locals. - The drought is said to be triggered by the El Nino and exacerbated by poor human management over
water sources. Six million sheep died.
Drought in Sahel (Climate case study)
- The Sahel region has been suffering from drought on a regular basis since the early 1980s. The area
naturally experiences alternating wet and dry seasons - Human activities such as overgrazing, overcultivation and collection of firewood can lead to
desertification, especially when combined with drought conditions - Drought leads to crop failure, soil erosion, famine and hunger.
- In Niger in 2004, the drought situation was made worse when a plague of locusts consumed the
remaining crops - Food is unsustainable in the long term, so development aid, which involves educating the local
community in farming practices
Australia (Over-abstraction case study)
- Murray-Darley Basin
- Covers 14% of the Australian land mass
- Provides 75% of Australia’s water
- Provides 40% of the national farm produce – key for economic development – created a system of 30
dams, 3500 weirs and a network of pipelines - Home to 2 million people
- Been a 5x increase in water extractions since the 1920’s
- Eutrophication, soil degradation, groundwater depletion are only some of the issues occurring
- National plan announced in January 2007
- New lower cap on the amount of water extracted from the basin
- National government investments in the Food Bowl Modernisation Project in
- Victoria to reduce Water loss caused by inefficient irrigation
Aral Sea (Over-Abstraction case study 2)
- Aral Sea was the fourth largest inland lake in the world, providing a wealth of important eco-systems to
communities - Soviet Union policy makers decided to divert fresh water from the rivers feeding the Aral Sea. This was
an essential part of their plans to increase Cotton Production. By 1960s, Aral Sea had begun to shrink, by
2005 it had lost more than half of its surface area. - 60,000 fishing jobs lost
Management plans to improve situation
- 1995, World Bank and Kazak government built a dam to prevent water flowing from northern section into
southern section - Met with success, from 2005 to 2007, surface area of sea’s northern section expanded by 800 square
km - Local economy growing as fish stocks re-introduced
- However, South Aral Sea still declining
Deforestation in the Amazonia (Deforestation case study)
- There has been huge amounts of deforestation over the last few decades in the Amazonia. Over twenty
percent of the forest has been destroyed, and this has been occurring at an accelerating rate over the
last 50 years. - The Amazon rainforests contain 60% of the worlds rainforests, so in such the environmental impacts on
global life support systems is bound to be highly significant
Why is the Amazon declining so fast?
- Cattle ranching which involves huge amounts of land
- Large scale commercial agriculture e.g. soya production and biofuels
- General development of towns and roads for a growing population
- Legal and illegal logging
What have the impacts been?
- Large scale aquifer depletion, water runs off and into the Amazon drainage basin, so less water infiltrates
to recharge them
- This had led to the possibility of increased flooding and mudslides
What impacts can surpluses in the hydrological cycle have
- Surpluses within the hydrological cycle can lead to flooding which can have disastrous impacts for
people, destroying social wellbeing and economic security
What two factors can cause flooding
- Meteorological causes of flooding include intense storms, causing flash flooding, heavy and prolonged
rainfall a series of depressions and extreme monsoonal rainfall and snow melt - Human actions such as urbanisation and deforestation increase flood risk. Urbanisation results in an
increase in impermeable surfaces, allowing for surface runoff, whilst deforestation reduces the amount of
water being intercepted, likewise increasing surface run-off
Somerset Flooding 2013-14 (Flooding case study)
Causes
- Low lying lands
- December 2013, several deep areas of low pressure moved across to the north of the British Isles,
bringing high wind speeds and heavy rain to many locations
Impacts
- Total of 165 properties on the Somerset levels suffered internal flooding
- Flooding and groundwater also disrupted services including trains on the Bristol to Exeter line
Work to prevent a re-occurrence of such an event
- Further dredging of the Rivers Parett and Tone
- The plan also proposed the construction of a tidal barrier
Boscastle floods 2004 (flooding case study 2)
Causes
• The drainage basin of Boscastle is steep and impermeable rock (granite)
• 89 mm of rain fell in less than an hour
• There was very saturated ground from previous rainfall.
• Topography of the land. The landscape upstream of Boscastle, a steep-sided valley, acted as a funnel
directing vast volumes of water into the village.
Impacts
• 75 cars, 5 caravans, 6 buildings and several boats were washed into the sea
• 100 homes and businesses were destroyed
• 15 million pounds in damages
Work to prevent a re-occurrence of such an event
• Widening and deepening the river channel – allows the river to carry more water
• Removing the low bridges and replacing them with wider bridges – this meant large amounts of water
could flow freely underneath the bridge, so it would not act like a dam
• Using permeable surfaces
Pakistan Floods 2010 (Flooding Case Study 3)
Causes
- Exceptional rainfall, including 60 hours of continuous rainfall, which exceeded the usual total for the
three months of the monsoon season in this region by 30%
- Created a tsunami like wave of water that tore through the valleys
- Swat Valley had suffered widespread deforestation while under the control of the Taliban
- In Sind, levees had caused the embankment to be raised above the surrounding plains, left them
exposed to extensive flooding in the event of the levee being breached or overtopped
Impacts
- One fifth of Pakistan was submerged by the floods
- Vast stretches of countryside became swamps or resembled an inland sea
- 11 thousand villages inundated
- 1.2 million houses were damaged or destroyed
- Cost of agriculture put up 1.5 billion
- 1600 deaths
- 14 million affected
- Most flood victims were poor, rural peasants whose limited assets consisted of their houses, farmland
and animals. In many cases the floodwaters destroyed all three, leaving people destitute and homeless
refugees
Response failures
- Government failed to provide any emergency supplies: no food, water, tents blankets or medicines
- Funds for aid were short as a mere 5% of Pakistanis pay tax
- International response unexpectedly sluggish and ungenerous
What are the fundamental water security issues
- There is a growing mismatch between water supply and demand, due to growing population,
outstripping supply, since fresh water is a finite source - Led to patterns of water stress
- Humans exacerbate these physical issues due to factors such as over abstraction from rivers, lakes and
groundwater, water contamination from agriculture and industrial water pollution - Rising demands, due to increased populations, improving standards of living, industrialisation and
agriculture. - According to the international Water Management institute research organisation water stress is
increasing and 1/3 of all people face some sort of water scarcity
What is green, blue and grey water
Blue Water – freshwater taken from Surface Water and Ground Water recourses
Green Water – freshwater taken from rainwater stored in the soil such as soil moisture
Grey Water – Polluted water
What is water stress
- Often taken as less than 1700m^3 per person per year
- Occurs when the shortage of fresh water threatens food production and damages ecosystems
- Declining standards of reliability and service - Harvest failures and food insecurity
What is water scarcity and explain the four types
- Supply of water per person falls below 1000m^3 per year
- Physical water scarcity: more than 75% of river flows are allocated to agriculture, industries or domestic
purposes - Approaching physical water scarcity: more than 60% of river flows are allocated. These basins will
experience physical water scarcity in the near future - Economic water scarcity: water recourses are abundant relative to water use, with less than 25% of
water from rivers withdrawn for human purposes, but malnutrition exists - Little or no water scarcity: abundant water recourses relative to use. Less than 25% withdrawn for human
use
India (Water scarcity case studies)
China (Water scarcity case studies)
India
- India has 4% of the world’s freshwater, but 16% of world population.
- Demand will exceed supply by 2020, as urban water demand is expected to double and industrial
demand to triple.
- Hydrologists calculate that 43% of precipitation never reaches rivers or aquifers, and water tables are
falling rapidly as 21 million wells abstract water.
Pearl River, China, (Pollution of water supply case study)
- The Pearl River in China is highly polluted
- The Delta, which accounts for 10% of China’s GDP, has undergone rapid urbanisation. The rapid growth
in cities has contributed to environmental degradation in the Delta - Polluted water is killing crops in the Pearl River Delta
- 9000 tonnes of heavy metals, 66,000 tonnes of nitrates and ammonia and 60,000 tonnes of petrol are
deposited into the sea every year by the river - The World Bank has approved a 96 million loan to reduce water pollution
- Guangzhou has built 30 treatment plants which aim to cut sewage by 85%
Spanish Coast (Salt Water intrusion case study)
- 60% of aquifers are experiencing saline intrusion due to irrigation and overuse by tourism
- La Plana de Castellon is an aquifer mostly used for irrigation in farming. The increase in demand for
water due to the increase in agriculture has places stress on the aquifer. - This has caused the aquifer to decrease
How could water insecurity lead to water conflicts
- Water supply is vital for economic development, needed for activities in industry, energy supply and
agriculture - It is also very important for human wellbeing such as sanitation, health and food
- A lack of water will have detrimental impacts on the economy, environment and human wellbeing
- This is likely to cause transboundary and international conflicts
Middle East (Water Conflict Case Study 1)
- In the western part of this region, Israelis, Syrians, Jordanians, Lebanese and Palestinians are in dispute
over shrinking water supplies. Security of water supplies was not the cause of the Arab-Israeli war, but
was a contributing factor - In the Western part of the region, Turkey plans to build dams to store water and use water in the
headwaters of the Tigris and Euphrates Rivers. This is strongly opposed by Syria and Iraq, where reduced
water supplies threaten to hold back economic development and food production
-
The Colorado River (Water Conflict case study 2)
The Colorado River Basin is 630,000 km^2 in area. The Colorado and its tributaries drain south-western Wyoming and western Colorado, parts of Utah, New Mexico and California, and almost all of Arizona.
Use of water from the Colorado is a controversial issue, there is much conflict between the potential users:
- Those who live in the upper parts of the basin
- Those who live in the lower part of the basin, including Arizona, whose population increased by 40%
since the 1980s - Farmers, who want the water for irrigation
A number of treaties have been established by the government between 1922 and 1948. Water has been allocated to various users in different parts of the basin.
- The biggest loser is Mexico
- 90% of water has been abstracted from the river before it reaches the international border
- Irrigation water extracted from the river is supposed to be put back in to maintain the flow in Mexico
- However, this water is very saline and unsuitable for Mexican farmers
- The increasingly severe competition for whatever small quantities remain of the Colorado river keeps
the basin tied up in legal disputes and controversy
Explain the uncertainties surrounding the future of water supply
- Climate change is occurring, but its exact impact cannot be predicted
- Continued economic growth is not inevitable as the ‘credit crunch’ has shown
- Population growth is slowing due to lower birth rates and higher death rates
- Political and religious conflicts can create severe shocks demographically and economically
Therefore, current trends in water demand may not necessarily continue into the future
How is climate change effecting the water cycle
- Climate change effects the inputs and outputs of the hydrological cycle by altering precipitation and
evaporation rates. - Some areas are likely to face flooding, such as Bangladesh as it is on low lying land, whilst other regions
will face prolonged drought, such as the Sahel region in Africa - Climate change has an impact on stores, flows, size of snow and glacier mass, reservoir, lakes,
permafrost, soil, moisture levels and runoff rates - Rainfall patterns in Africa are moving away from the continent’s interior to its coasts, leaving millions of
people inland without enough water for consumption or food production - The area’s most likely to suffer water shortages include western Asia, the Middle East, Central America,
and the Mediterranean and Amazon basins - Climate change’s impacts are uncertain, causing concern over water supplies and efficiency of
management
Who are the stakeholders and decision makers in water management and supply
- There are many individuals, pressure groups and political movements, governments, businesses, charities
and agencies involved in monitoring and managing water recourses
- Water companies
- Environmentalists
- Individuals
- Intergovernmental organisations
- Governments
How do water companies influence the managing of water supply
- TNCS such as Viendi and Suez are companies that provide technological fixes
- They control the price of water and can choose not to supply certain areas
How do water Environmentalists influence the managing of water supply
- WWF and Friends of the Earth
- Includes many scientists and researchers
- Important for pressuring against controversial or damaging projects towards water supply
How do Individuals influence the managing of water supply
- Individuals that abstract their own water are relatively self-sufficient
- They must, however, conform to drought restrictions placed by governments in order to increase the
security of supply in the future by reducing over-abstraction - In general, individuals have little power over the actions of governments or water companies
How do Intergovernmental Organisations influence the managing of water supply
- World Bank funds megaprojects to improve supply. It is environmentally conscious.
- G8 summits have increased the focus on water and the amount of aid reaching LICs – they highlight the
need for more integrated management of water recourses
How do Governments influence the managing of water supply
- Governments play a key role in securing water supplies for citizens as they can back and fund large and
small projects that increase water security - Pivotal in the implementation of international treaties
- Able to provide water companies with licenses to abstract water from aquifers and build dams
- Governments decide whether the water network is nationalised – which impacts water prices
- Tariffs and taxes on water can also be implemented by governments
What are the cons surrounding the privatisation of water supply
- Many organisations actively criticise the actions of water companies for being motivated primarily by
profit rather than public welfare - Can expose people to exploitation
- Some companies encounter resistance as they have increased the prices of water to cover the cost of
investment
Explain the sustainable water management programme
- Involves a careful balance between supplying personal needs, economic demands and the conservation of
the natural environment - 4 stages
Groundwater Management:
Aquifer storage
Groundwater quality
Waterway management:
River rehabilitation
Sustainable water allocation
Environmental flows
Integrated urban water management:
Water treatment technology
Water sensitive urban design
Water harvesting and reuse
Monitoring technology
Sensor technologies
Real-time wireless monitoring and control systems
Singapore (Integrated Water Management Case Study)
- Singapore is a city-state population of 5.4 million (entirely urban) inhabitant in mid-2015
- It receives abundant rainfall, however has water scarcity issues due to:
The limited land for collection and storage
The effects of high evaporation rates due to the tropical climate
Lack of groundwater recourses
Singapore’s water agency (PUB) has therefore invested in research and technology to create diversified water supply:
Local catchment water involved collecting rainwater through a network of drains, canals, rivers, storm-
collection ponds and reservoirs
Singapore has retained an agreement with Malaysia to import water until 2061
NEWater - High-grade recycled water produced from grey water that is treated and further purified using
advanced technologies and ultraviolet disinfection, making it safe to drink
Singapore’s NEWater plants can meet up to 30% of the nation’s current water needs
By 2060 – it is hoped this can meet 55%
Middle East and California (Desalinisation Case Studies)
- More than half of seawater desalinisation capacity is in the Middle East and it provided 70% of Saudi
Arabia’s water - It is the most expensive option for water supply due to its energy use
- In California, however, the technology is being used more effectively – using brackish water from
underground and although energy intensive – uses 30% less energy than conventional methods
Nile River and Kielder (Transfer Scheme Case Studies)
- The Egyptian government has made developments to reduce losses through evaporation from natural
bodies of water - Jonglei Canal developed – transfers White Nile water around the swamps in Sudan, increased water
supply - In Kielder, Northumberland, the reservoir of 200 billion litres releases water into the North Tyne River. It
regulates a number of rivers in North-east England. - Pumping stations at Riding Mill and Frosterly allow for the transfer of water between rivers to regulate
the water levels - Transfer to areas of water scarcity
London (Treatment Plants Case Study)
- Treatment plants are used to make water more potable
- Plants in the Lea Valley, London, are used to recharge the chalk aquifers to prevent subsidence and
increase the volume of water stored in case of a drought - Treatment plants use huge levels of energy 2-3% of UKs electric power
River Danube (International treaties case study)
- The River Danube is a trans-boundary source, but international agreement has stopped conflicts
- Flows through 17 countries
- Provides drinking water for 10 million people
- 1998 – International Commission for the protection of Danube River, compromising 13-member states
and the EU - Treaty promotes and coordinates sustainable and equitable water management of the river, including
conservation, improvement and rational use of the water of the, its tributaries and groundwater source. - 60% of EUs land used for farming
Explain why Intermediate technologies are of important use
- In most less economically developed countries, not only are high-tech industries too expensive to
develop, they are usually inappropriate to the needs of the local people and to the environment in which
they live. - An appropriate technology can contribute to a more sustainable way of life for people who are rich or
poor, living in places that may developed or developing - Some examples include fog nets, water harvesting and pumpkin tanks
Nepal (Gravity Fed Schemes) (Intermediate technology)
- Multiple Use Water Systems have been built, supported by NGO Practical Action
- They use local materials and simple technology to bring water to where it is needed by gravity and a
system of pipes - Water is moved from springs and streams to supply agriculture and people
- e.g. (Dailekh)
Africa (Hand Dug wells) (Intermediate technology)
- Most common method of getting water
- Traditional hand-dug wells often dry out as they are too polluted
- Can become breeding grounds for insects – diseases such as malaria
- New technology combines tradition with additional features to prevent these problems
- Lined with concrete to prevent pollution and make them more stable
- Depths vary, but always ensure water table can still be reached during the dry season
An example of one of our project sites is in Western Kenya, where we fund a young NGO known as The Bridge Water Project. Many of the drillers on this team have had experience deep in a hang dug wells.
Today however, they are working with new, small rigs provided by donors. These simple machines can dig to about 150-200 feet. The rigs are very cost effective and in this region of Kenya do a good job. They can be moved with ease and allow work to happen quickly.
economic impact of flooding in the 2012-2013 foods
The economic damage from flooding of residential and non-residential properties is estimated to
be between about £200 million and £277 million.
The other major impacts, such as disruption to
transport and infrastructure, and indirect impacts on communities, businesses and the local
economy, are much less certain. These can only be given in very broad terms, but could bring the
total economic impacts through the year to between about £260 million and £620 million.
Kaveri River water dispute India
The sharing of waters of the Kaveri River (also spelled as Cauvery) has been the source of a serious conflict between the two states of Tamil Nadu and Karnataka.
The genesis of this conflict rests in two agreements in 1892 and 1924 between the Madras Presidency and Kingdom of Mysore. The 802 kilometres (498 mi) Cauvery river has 44,000 km2 basin area in Tamil Nadu and 32,000 km2 basin area in Karnataka.
The inflow from Karnataka is 425 TMCft whereas that from Tamil Nadu is 252 TMCft [2]
Based on the inflow Karnataka is demanding its due share of water from the river. It states that the pre-independence agreements are invalid and are skewed heavily in the favour of the Madras Presidency, and has demanded a renegotiated settlement based on “equitable sharing of the waters”.
Tamil Nadu, on the other hand, pleads that it has already developed almost 3,000,000 acres (12,000 km2) of land and as a result has come to depend very heavily on the existing pattern of usage.
Any change in this pattern, it says, will adversely affect the livelihood of millions of farmers in the state.
As water issues largely fall under the authority of the states, inter-state water disputes have a long tradition in the Cauvery river basin. Future changes in precipitation during the two monsoon seasons will only increase these tensions. Both states depend on the arrival of these monsoon rains to water their crops and to replenish the groundwater.
Arab israli war (water conflict)
The third violation of the truce arose as a result of the failure of the Transjordan and Iraqi forces to permit the flow of water to Jerusalem.[178]
China (Water scarcity case studies)
China (South-North Transfer Project)
- China has 8% of the world’s freshwater but must meet the needs of 22% of the world’s population.
- Two-thirds of Chinese cities do not have enough water all year round, and national water supplies are
likely to reach stress levels by 2030.
- China uses irrigation to produce 70% of its food, mostly in the north and northeast, where the Yellow
River and major aquifers are running dry.
- Huge engineering projects transfer water to this area from the water-rich south
- The South North project is a gigantic project enacted in 2003, costs of US$100 billion
- Project involves building three canal that run 1300km – however, there are worries of the likelihood of
significant ecological and environmental impacts
Li Bing’s Irrigation System consists of three main constructions that work in harmony with one another to ensure against flooding and keep the fields well supplied with water
