This dataset provides a common validation set for estimates of gross primary productivity. This data represents a subset of all predictions made in the model inputs and outputs that were converted to GPP based on a light use efficiency. The data was subsetted for only days were all light estimates could be produced. This dataset is part of a larger data release of inputs and outputs from a model to predict light at the stream surface and within the water column for 173 streams and rivers across the continental United States. The complete release contains model input data, modeled estimates of light at the stream surface and within the water column, and modeled estimates of gross primary productivity.