Irrigation and Drainage
Irrigation and Drainage
Irrigation and Drainage
DRAINAGE
Increased socio-economic
Land drainage
Closed drain into a ditch is made of a large stone on top of two other stones.
‘During the Middle Ages, in the countries around the North Sea, people
In how far the actual performance of these systems can be forecast by the above
models, however, is largely unknown. There is a great need for field research in
this direction.
production volume, drainage has a role to play here. The slogan of engineering
Why drainage?
4. protection of water quality
Costs of new irrigation projects will increase further when
adequate drainage is included. Assuming an annual loss of
between 0.5 and 1.0 million hectares that cost between US$
8,000 or 10,000 for surface irrigation schemes, overall losses
amount to US$ 4/ 8 to 5/10 billion.
5. infrastructure serves rural and urban residents as well as
industry
6. protects human lives and assets against flooding and high
groundwater levels
7. improve health conditions
Land drainage
60
50
40
30
20
10
Aspects to be covered
Agricultural land drainage has:
The soil physical processes include soil aeration, soil structure,
soil stability, and soil temperature.
The chemical processes include salinity soil acidity and soil
alkalinity
The hydrological processes include evaporation runoff and soil
salinity.
environmental hydrological,
engineering ecological and
sociopolitical aspects.
All these aspects can be subject of drainage research.
Land drainage cont.
Risk of reuse
The salinity of drainage water during the irrigation season ranged from 7.2 to 8.6 dS/m’
(SAR, 8.3 to 10.7). The salinity from pre-sowing irrigation with drainage water of 8.2
dS/m could decreased the straw and grain yield of wheat significantly. Taking the wheat
yield obtained with canal water as the potential (l00%), the mean relative yield of wheat
irrigated with only saline drainage water was 63%, whereas substitution of canal water for
pre-plant irrigation and
Land drainage cont
Mitigation of risk
The slogan is: Reduce potential negative impacts at the
outset, and not at the end of the drain.
Improvements in land and water management and wastewater
treatment prior to its disposal in drains reduce negative effects on
freshwater ecosystems and health and facilitate drainage
management
Land drainage cont.
Research areas
The economic and environmental impacts of drainage systems are
also matters of concern at the DRI.
The performance of drainage systems is the measure of their success
against the relevant design bjectives.
types:
standard statistical types; `
conceptual statistical types;
conceptual deterministic types.
Data analysis
standard statistical types
routinely to assess the characteristics of the measured parameters
and to detect trends `
Time series:
are made of time dependent data to obtain insight in the time-variation and/or time-
trends.
To detect time trends of the variables, the data can best be analysed in graphic from.
Correlation analysis:
is applied to detect a trend between two or more parameters/factors even though the
relation between them is diffuse (scattered).
Data analysis
Data analysis
The depth of the water table as a criterion factor needs to be translated into a criterion
index to be given a numerical value that represents the behavior of the water table on
the one hand and that can be related to the target (e.g. crop production) on the other
hand.
The relation between criterion index and target can often be optimized, the maximum
value providing the ultimate aim while the corresponding value of the criterion index
can be used as an agricultural drainage criterion in the design procedure.
Thank you