Disturbance Parameterization in the National Water Model

Increased likelihood and intensity of wildfires and other disturbances (i.e., drought, wildfire, floods, beetle infestations) are remaking the land cover of the United States (U.S.). Communities at risk of such disturbances can better prepare when research and operational agencies work together to predict these disturbances and their effects. Unfortunately, these groups currently lack suitable predictive models that can accurately capture disturbances to the hydrologic (re: water) cycle (i.e., extreme precipitation, drought, flash floods, wildfire) in forested systems and watersheds across the U.S.

To address this need, the goal of this project is to develop sets of parameters and modeling configurations within NOAA’s flexible modeling framework, NextGen. Doing so will allow improved prediction of changes to the hydrologic cycle (i.e., changes to precipitation, humidity, drought) under rapid and long-term conditions and in the face of various disturbance types (i.e., beetles, forest harvesting, wildfires).

The methodology will first involve identifying region-specific controls (i.e., humidity, land cover, soil type, evaporation rate) on post-disturbance hydrology across the U.S. This will include working with river forecast centers (RFCs) and NOAA collaborators to identify sites that can be used to test for various kinds of disturbance conditions across the U.S. Once chosen, the test sites will be grouped to determine region-specific variables controlling post-disturbance hydrology. With parameters identified, we will then compile disturbance parameters sets for the NextGen framework and RFC hydrologic models. Once the parameter sets have been vetted, we will model for different situations such as those varying in time (i.e., daily vs annually) and space (locally vs nationally) after which we will evaluate the parameter sets within the CIROH testbed at the Colorado School of Mines. Given the project’s recent FY23 financial support, the execution of tasks has only recently begun and there are not yet key findings to report. However, the project is on track, and we look forward to disseminating findings as soon as possible.

The operational benefit of the project is in firstly creating a range of products and outreach that will advance our understanding and hydrologic prediction in watersheds across the CONUS that have been impacted by disturbances. We expect to develop a national-scale hydrologic dataset that includes test sites and ecologically-distinct regions that can be used by any model that is compatible with the NextGen framework. We further expect this project to enhance disturbance-aware modeling configurations such that they can be used to accurately forecast disturbance impacts (similar to how weather is forecasted), thereby improving the utility of operational forecasting for prediction in a manner that can ultimately serve communities at risk.