SPARROW model inputs and simulated Total Nitrogen and Total Phosphorus loads in the Clear Lake watershed, California

The existing long-term Total Nitrogen (TN) and Total Phosphorus (TP) steady-state models, originally developed on a regional scale for the Pacific Region of the United States (Wise, 2019), were utilized to estimate TN and TP loads for the Clear Lake watershed. To support this analysis, input data for the Pacific Region model were updated to reflect climate, land use, and agricultural activities for the 2016-2024 period. Following these updates, the models were run in prediction mode, using model coefficients from the 2012 Pacific Region TN and TP SPARROW models. Model data set updates included incorporating the 2019 National Land Cover Data (NLCD), 2017 county-level applied agricultural fertilizer and manure data, updated streamflow data representing 2016-2024 conditions, and adjustments for areas affected by the 2017 and 2018 wildfires in the Clear Lake watershed. The revised Pacific Region SPARROW models were then run in prediction mode, and the resulting TN and TP load estimates were compared to those from the 2012 Pacific Region model to assess changes in TN and TP loads relative to historical conditions. Initially developed in the Statistical Analysis System (SAS), the Pacific Region SPARROW models were converted to R (RSPARROW) for this analysis. RSPARROW is available at https://doi.org/10.5066/P9G64CAN.

[
  "010:12"
]

[
  "geospatial"
]