This project addresses the research priority on the national-scale evaluation of the water budget
with emphasis on CONUS404. The proposed research involves comparing CONUS404 water-
budget components against in-situ and remotely-sensed observations as well as data from other
reanalysis and gridded datasets. Comparisons will be done at several spatial and temporal units of
Analysis of the U.S. water budget using CONUS404 analysis.

This proposal will implement two different methods to quantify uncertainties and errors,
Triple Collocation and Numerical Moment Matching. First, we will study uncertainties and biases
for each one of the components in the water budget equation independently. Second, we will study
how the component-wise calculated errors are correlated. In addition, this project will perform
storm frequency analysis using CONUS404 data and compare the results against values reported
in NOAA Atlas 14. There is a version of CONUS404 with bias-corrected precipitation and
temperature (using DAYMET and PRISM, Grim et al. 2022). The proposed work will provide a
more robust evaluation of CONUS404 precipitation since it is based on multiple gridded datasets.
In addition, this project will also assess bias and uncertainties of all the other components of the
water budget. Resources from this project will help to train a PhD student and the project results
will be disseminated through the collaboration with the USGS co-PIs, journal articles, and
conference presentations. In addition, the project will develop a web-based app to facilitate the
dissemination of the project findings. Co-PIs are involved with the evaluation team of the Hydro-
Terrestrial Earth System Testbed (HyTEST) project of the USGS Water Mission Area (WMA),
and the Illinois River Basin Integrated Water Availability Assessment (IWAA). These two
projects, as well as others at the USGS, stand to benefit from the proposed research.