Model Library

Water Quantity and Quality Model for Paddy IDUs (WQQM-PIDU)

Model name: Water Quantity and Quality Model for Paddy IDUs (WQQM-PIDU)

Developed by: Researchers at Chinese Academy of Sciences, Chinese Academy of Agricultural Sciences and Shanghai Jiao Tong University, led by Dr. Sisi Li and Dr. Liang Zhang, and their collaborators (Last update: 2023)

Model type: Process-based, hydrological and water quality, field-scale and irrigation and drainage unit (IDU)-scale model

Computational requirements: N/A

Software requirements: GIS: optional

Link to download model

Capabilities and Limitations:

Capabilities

  • It can represent different irrigation drainage systems (Li et al., 2020);
  • It can simulate daily water quantity and quality variations in paddy irrigation drainage units composed of fields, parallel 1st order ditches, parallel 2nd order ditches and a pond (Li et al., 2020; Li et al., 2023).

Limitations

  • The WQQM-PIDU model is newly developed and has not been widely applied (Li et al., 2020; Li et al., 2023);
  • Model simplifications, such as not accounting for plant growth effects and water quality decline (Li et al., 2020);
  • WQQM-PIDU was specifically designed for irrigation and drainage unit (IDU) and field scales (Li et al., 2020);
  • The model represents only proper drainage, which may result in modeled discharge and loads at the IDU outlet being lower than those at the field edge (Li et al., 2020).

Model Inputs and Outputs: 

Inputs

Daily climate data, Controlling field water level management schemes, Shape parameters of ditches and ponds.

Outputs

WQQM-PIDU can simulate daily water levels and nutrient concentrations of field ponding water, ditch water and pond water as well as nutrient loads in surface discharge and leaching from both the field scale and the IDU scale.

Example:

Reference

Li, S., Liu, H., Zhang, L., Li, X., Wang, H., Zhuang, Y., Zhang, F., Zhai, L., Fan, X., Hu, W., & Pan, J. (2020). Potential nutrient removal function of naturally existed ditches and ponds in paddy regions: Prospect of enhancing water quality by irrigation and drainage management. Science of The Total Environment, 718, 137418. https://doi.org/10.1016/j.scitotenv.2020.137418

Objective

The objective of the study is to assess the effects of rice growing on surrounding surface waters by studying the nutrient removal function of naturally existing ditches and ponds in paddy regions, using monitoring and modeling approaches, and to discuss irrigation and drainage management practices to enhance water quality.