1. Comparison of Genetic Algorithm and WASAM model for Real Time Water Allocation: A Case Study of Song Phi Nong Irrigation Project
Bhaktikul, K Mahidol University
Soiprasert, N Royal Irrigation Department
Sombunying, W Chulalongkorn University

2. Introduction Irrigation System Management Water availability :
Wet year
Normal year
Drought year
Water requirement varies by weekly / monthly
Optimal water supply : supply = demand

3. Introduction Saving water to next period or downstream projects
Decision on real time
Limit of available software
Mathematical model for complex system

4. Objectives
To determine optimal water allocation in various water supply situation by optimization technique (GA)
Song Phi Nong Irrigation Project which covers area
of 300,000 rai and 32 irrigation schemes
Study area

5. Study area Seasonal water requirement is in range 0.0 – 5.65 m3/s
Max. canal capacity 0.42 – m3/s

6. Irrigation System model
- Inflow node
- Demand node
- Sink node

7. Problem Formulation Objective function If nodal balance > 0.001
Where di = irrigation demand for schemes i
xi = irrigation supply to schemes i.
R1 = coefficient of penalty function (P1)
R2 = coefficient of penalty function (P2)
If nodal balance > 0.001
If xi > di

8. Problem Formulation Constraint :
1. Canal flow <= max. canal capacity
2. nodal balance = 0.0
3. supply <= demand

9. Model development
- Written in C
Programming
- 9 sub routines

10. Input requirement

11. Input requirement

12. Parameters Sensitivity

13. Parameters Sensitivity

14. Parameters Sensitivity

15. Study results Drought period
GA model give equity in supply in each canal.
The ratio of water supply to demand was nearly equal to 0.6, 0.7, 0.8, and 0.9 in every week.
WASAM model can not operate in this period

16. Study results Normal and flood period
GA model give supply in each canal not over demand
Both GA and WASAM give
the similar results

17. Study results
Q (m3/s)
Canal No.

18. Thank you for your attention