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Trend Departure Index Results for sites in the RESTORE Trend Analysis and Hydrologic Alteration Studies

November 4, 2020

This dataset includes results of the Trend Departure Index (TDI) for 139 sites in the RESTORE trend analysis study and approximately 9,200 HUC12 pour points in the streamflow alteration study. Data from the 139 sites in the trend analysis were compared against reference site data from the GAGES II dataset (Falcone and others, 2010) and were used to calculate the departure from reference conditions. The streamflow alteration study used pre- and post-periods of analysis to quantify hydrologic alteration in terms of a ratio. The TDI is a ratio of the difference between two sites divided by 365 (total number of trends per site). TDI varies from 0 to 1; a TDI of 0 indicates the trend results for the site are identical to the reference site and any value larger than 0 indicates some departure compared to the reference condition. The larger the number (the closer to 1), the more departure or deviation relative to the reference site in trend across all quantiles for the site. The TDI is divided into interquartile ranges with levels of departure as follows: 0.00-0.22, fewest departures; 0.23- 0.44, low- to-moderate departures; 0.45-0.66, moderate-to-high departures; and 0.67-1.00, most departures. Trend Departure for each inter-decadal period is included in the trend analysis study and for the entire period of record for the streamflow alterations analysis. The Site_Info.zip and the Site_Info_Master.csv from Robinson and others (2020) can be used to cross reference sites with the basin characteristics .csv file from Crowley-Ornelas and others (2019). Crowley-Ornelas, E.R., Worland, S.C., Wieczorek, M.E., Asquith, W.H., Knight, R.R., 2019, Summary of basin characteristics for National Hydrography Dataset, version 2 catchments in the Southeastern United States, 1950 - 2010: U.S. Geological Survey data release, https://doi.org/10.5066/P9KXTDU4. Falcone, J.A.; Carlisle, D.M.; Wolock D.M.; Meador, M.R. 2010, GAGES: A stream gage database for evaluating natural and altered flow conditions in the conterminous United States: Ecology, v. 91, p. 62, https://esajournals.onlinelibrary.wiley.com/doi/10.1890/09-0889. Robinson, A.L., Worland, S.C., and Rodgers, K.D., 2020, Estimated daily mean streamflows for HUC12 pour points in the southeastern United States, 1950 - 2009: U.S. Geological Survey data release, https://doi.org/10.5066/P9P36GXZ.