A modified response matrix method to approximate SWAT for computationally intense applications

Shaobin Li, Kevin Wallington, Sundar Niroula, Ximing Cai

Research output: Contribution to journalArticlepeer-review


The computational burden of running a semi-distributed hydrological model numerous times, such as for optimization applications, can be exorbitant. This study provides a surrogate model to estimate streamflow, nutrient, and sediment export under spatially distributed management decisions. Specifically, we surrogate the Soil and Water Assessment Tool (SWAT) using a modified response matrix (RM) approach. A traditional RM approach applied to SWAT assumes hydrological responses are approximated by linear functions of management decisions, and falls short in accounting for in-stream and reservoir processes. Here, we explain and illustrate three key modifications that address interaction effects between co-located conservation practices and in-stream and reservoir processes affecting nutrient and sediment loads. The modified RM approach provides excellent estimation (Nash-Sutcliffe Efficiency, NSE >0.95) for streamflow and nutrient export throughout the stream network and provides very good estimation (NSE >0.85) for sediment export at most, though not all, points in the stream network.

Original languageEnglish (US)
Article number105269
JournalEnvironmental Modelling and Software
StatePublished - Feb 2022


  • Management decisions
  • Nutrient transport
  • Soil and water assessment tool (SWAT)
  • Surrogate modeling
  • Watershed modeling

ASJC Scopus subject areas

  • Software
  • Environmental Engineering
  • Ecological Modeling


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