This study compared the characteristics of the optimization technique and the water supply and demand forecast using K-WEAP (Korea-Water Evaluation and Planning System) model and MODSIM (Modified SIMYLD) model considering wtaer supply priority. Currently, The national water resources plan applied same priority for municipal, industrial and agricultural demand. the K-WEAP model performs the ratio allocation to satisfy the maximum satisfaction rate, whereas the MODSIM model should be applied to the water supply priority of demands. As a result of applying the priority, water shortage decreased by an average of 1,035,000 m3 than same prioritized results. It is due to the increase of the return flow rate as the distribution of Municipal and industrial water increases. Comparing the analysis results of K-WEAP and MODSIM applying the priorities, the relative error was within 5.3% and the coefficient of determination (R2) was 0.9999. In addition, if both models provide reasonable water balance analysis results, K-WEAP is superior to GUI convenience for model construction and data processing. However, MODSIM is more effective in simulation time efficiency. It is expected that it will be able to carry out analysis according to various scenarios using the model.

1. Ahn, S. R., Park, G. A., Shin, Y. H., and Kim, S. J. (2009). “Assessment of the potential water supply rate of agricultural irrigation facilities using MODSIM - For Geum River Basin -.” Journal of Korea Water Resources Association, Vol. 42, No. 10, pp. 825-843.  

2. 

3. Choi, S. J., Kang, S. K., Lee, D. R., and Kim, J. H. (2018). “A study on water supply and demand prospects for water resources planning.” Journal of the Korean Society of Hazard Mitigation, Vol. 18, No. 7, pp. 589-593.  

4. Choi, S. J., Lee, D. R., Moon, J. W., and Kang, S. K. (2010). “Application of K-WEAP”, Journal of Korea Water Resources Association, Vol. 43, No. 7, pp. 625-633.  

5. 

6. 

7. 

8. Lim, J. S., Kang, S. U., Kim, H. N., and Lee, E. L. (2017). “Evaluation of potential securing instream flow according to estimating operation rule in naeseongcheon watershed.” Journal of the Korean Society of Hazard Mitigation, Vol. 17, No. 1, pp. 265-277.  

9. 

10. 

11. 

12. Park, J. E., Kim, Y. S., Kim, J. K., and Koh, D. K. (2013). “Evaluation of spatio-temporal water shortage in sapgyo catchment employing total water right survey and water balance analysis.” Journal of Korea Water Resources Association, Vol. 46, No. 10, pp. 1005-1016.  

13. 

14.