Local water year for HU4 hydrological areas across the conterminous U.S.

This dataset was generated as part of a project that quantifies how natural lakes (NLs) and reservoirs (RSVRs) across the conterminous U.S. (CONUS) with different levels of hydrologic connectivity respond to drought and how natural and human factors operating at multiple spatial scales affect lake responses.Traditionally, the effects of precipitation on aquatic systems have been analyzed based on a calendar year (i.e., January-December), which cannot capture the asynchrony between precipitation and its impacts. To better quantify the contribution of precipitation to surface runoff, take into account the regional variation in water flow patterns, and fully understand ecosystems’ responses to droughts, a timeframe that takes into account both timing and lag effects should be considered. Wasko et al. (2020) proposed a more local-focused definition of the water year (i.e., local water year, LWY) where the LWY of each site is defined as the 12-month-period starting from the month with the lowest local streamflow. However, data from Wasko et al. (2020) did not cover all the HU4 (4-digit Hydrologic Unit) hydrological areas across the conterminous U.S. (CONUS). Using their definition and data, we employed a spatial interpolation method to estimate the LWY for all the HU4 hydrological areas across the CONUS.