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Overview |
Crop Production |
Crop Pattern |
Crop Yield |
Irrigation |
Soil Management | Precision Farming |
Relevant Products |
Relevant Links
Development of a model for dam irrigation management based on GIS network models
Finally, to calculate the efficiency of the network in a region, the average efficiencies for channels of level two, three and four are calculated separately and then multiplied.
3.2. Defining the water demand for each village
To define the water demand of a village, the table of water demands of plants (cultivation types) is used. By multiplying the water demand per area unit of each cultivation type by the area of that cultivation and addition of the resulted values, the whole water demand of that village is calculated.
3.3. Defining the relation between consumption nodes of the network and farms
To simplify the calculations of water demand, the village as the aggregation of all its farms is connected to the end nodes (consumption nodes) of the network, through a unique identifier. This means that this village is receiving water from that gate/turnout. Having the water demand of villages, the demand of each consumption node can be extracted.
3.4. Calculating the water demand of the whole network
Having the demand of end nodes of the network and adding them in each region, the region water demand can be resulted. By multiplying this with the region efficiency, the real water demand of that region is calculated.
Finally, by adding the real demands of all regions and other non-agriculture consumptions, and multiplying the result by the efficiency of the level-one channel, the real demand of the whole network is achieved. Now this value is compared with the water volume expected to be provided by the water source. If the demand is less than the capacity of the source, then we only need to plan the circling of water (define the irrigation periods) among level-three channels. Otherwise, first, the non-agricultural consumers are cut off; then if the problem remains, the agricultural consumers are classified based on some priorities. Using these priorities, the water portion for each level-two channel obtained and irrigation turns and periods for channels of level three are defined. Although for both these conditions, the portion of water for each channel of level two is defined.
4. Conclusion
In this article, a model is proposed for calculating the efficiency of the irrigation network and using it for the calculation of the water demand. The following results could be mentioned:
- In this method, the conveyance efficiency of the network can be calculated with much more accuracy than the empirical judgements traditionally used.
- The efficiency of each link/channel and region of the network can be calculated separately. Accordingly, proper actions can be taken to improve non-efficient parts.
- The network demand can be calculated more realistically and accurately, which causes better decisions.
- The water dedicated to each consumption type can be calculated.
- In both cases, presence or lack of water shortage, the irrigation cyclic plan and periods for channels of level three should be defined.
References
- Burt, C.M., A.J.Clemmens, T.S.Strelkoff, K.H.Solomon, R.D.Bliensner, L.A.Hardy, T.A.Howell & D.E.Eisenhauer, 1997.Irrigation performance measures: Efficiency and Uniformity, Journal of Irrigation and Drainage Engineering 123, 423-442.
- Irani, K.S., 2004.Importance of agriculture water use optimization and changing water distribution management from government to persons, Goharan Kavir, 196-199
- Khuzestan's energy organization, 2000.water engineering standards
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