Last Updated on 6/16/2023 by Homa Salehabadi (homa.salehabadi@gmail.com)

Streamflow sequences for three drought scenarios were developed to characterize plausible future drought conditions in the Colorado River Basin as described by Salehabadi, Tarboton et al. (2020) and Salehabadi and Tarboton (2022). 

The dataset is available in two different formats:

1- CRSS-Ready-To-Use Input Files (CRSSInputFileFormat.zip)
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This format includes all the water supply input files that are required to run CRSS. These data are ready to be directly imported into CRSS.

In the "CRSSInputFileFormat" folder, there is a folder for each drought scenario ensemble as follows: 

      •  MillenniumDrought_2000_2020
      •  Mid20thCenturyDrought_1953_1977
      •  PaleoTreeRingDrought_1576_1600

Within each ensemble folder, there are 100 subfolders, each associated with a specific streamflow trace. Each trace folder contains 29 "Inflow Files" that provide flow data for 29 CRSS gages. Additionally, there are five other required input files within each trace folder included:

      •  HydrologyParameters.SupplyScenario
      •  HydrologyParameters.TraceNumber
      •  MeadFloodControlData.hydrologyIncrement
      •  MWD_ICS.SacWYType
      •  TMD_East_Slope_Supply.St_Vrain_Annual_Flow


The input file names are aligned with CRSS V.6 (CRSS.Mar2023).


2- Excel File Format
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This format includes the generated data in Excel files, organized by specific ensembles. Each ensemble folder contains Excel files that provide the following information:

      •  Monthly Intervening Natural Flows at 29 CRSS sites.
      •  Annual Water Year Intervening Natural Flows at 29 CRSS sites.
      •  Sacramento Water Year Type (MWD_ICS.SacWYType in CRSS)
      •  St Vrain Annual Flows (TMD_East_Slope_Supply.St_Vrain_Annual_Flow in CRSS)

The dataset structure is as follows:

Folder: MillenniumDrought_2000_2020
Excel files: 
      •  DroughtScenario_ObsResampled20002020_100Traces50Years_MonthlyIntervNF_WithSiteIDs.xlsx
      •  DroughtScenario_ObsResampled20002020_100Traces50Years_AnnualWYIntervNF_WithSiteIDs.xlsx
      •  DroughtScenario_ObsResampled20002020_100Traces50Years_MWD_ICS.SacWYType.xlsx
      •  DroughtScenario_ObsResampled20002020_100Traces50Years_TMD_East_Slope_Supply.St_Vrain_Annual_Flow.xlsx

Folder: Mid20thCenturyDrought_1953_1977
Excel files: 
      •  DroughtScenario_ObsResampled19531977_100Traces50Years_MonthlyIntervNF_WithSiteIDs.xlsx
      •  DroughtScenario_ObsResampled19531977_100Traces50Years_AnnualWYIntervNF_WithSiteIDs.xlsx
      •  DroughtScenario_ObsResampled19531977_100Traces50Years_MWD_ICS.SacWYType.xlsx
      •  DroughtScenario_ObsResampled19531977_100Traces50Years_TMD_East_Slope_Supply.St_Vrain_Annual_Flow.xlsx

Folder: PaleoTreeRingDrought_1576_1600
Excel files: 
      •  DroughtScenario_PaleoResampled15761600_100Traces50Years_MonthlyIntervNF_WithSiteIDs.xlsx
      •  DroughtScenario_PaleoResampled15761600_100Traces50Years_AnnualWYIntervNF_WithSiteIDs.xlsx
      •  DroughtScenario_PaleoResampled15761600_100Traces50Years_MWD_ICS.SacWYType.xlsx
      •  DroughtScenario_PaleoResampled15761600_100Traces50Years_TMD_East_Slope_Supply.St_Vrain_Annual_Flow.xlsx


The Excel files for Monthly and Annual Flows are comprised of 100 sheets, each containing a 50-year sequence (Trace) of monthly or annual streamflow at the 29 CRSS sites. USGS Gage Numbers (Streamflow Gaging site number) are used to identify each CRSS natural inflow site (ID = 1 to 29) for which flow is simulated. The corresponding USGS Gage Numbers and CRSS site IDs and a map of their locations are provided in an Excel file (USGSGages_CRSSSites_CorrespondingIDs.xlsx).

For the Monthly and Annual Flows in the Millennium and Mid-20th Century droughts, the first two columns (A and B) hold the water year and month selected from historical flows to simulate that year.  The remaining columns contain intervening natural flow for the corresponding site, in acre-ft.  Intervening natural flow refers to the streamflow originating directly from the subwatershed that drains into the site, without passing any upstream site.  
For the Paleo Tree-Ring drought, the Excel files for Monthly and Annual Flows have three leading columns.  Column A (wy_TR) represents the tree-ring reconstruction year sampled for that trace year.  Columns B and C hold the water year and month selected from historical flows as being closest to the tree-ring flow at Lees Ferry.  The remaining columns contain intervening natural flow for each site, after adjustment by the ratio of paleo flow to closest historical flow. 


Data 
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These files were generated using R programming, the US Bureau of Reclamation Natural Flow Database Excel file (last updated on 12/15/2022), Tree-Ring Reconstructed flow at Lees Ferry from the most skillful model of Meko et al. (2017), and historical data for Sacramento Water Year Type and St Vrain Annual Flows from CRSS.Mar2023.  



References
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Meko, D. M., C. A. Woodhouse and E. R. Bigio, (2017), "Southern California Tree-Ring Study," California Department of Water Resources, https://pdfs.semanticscholar.org/fbaf/487604e2537c8f51037035e59c13113edeeb.pdf.

Salehabadi, H., D. G. Tarboton, B. Udall, K. G. Wheeler and J. C. Schmidt, (2022), "An Assessment of Potential Severe Droughts in the Colorado River Basin," JAWRA Journal of the American Water Resources Association, 58(6): 1053-1075, https://doi.org/10.1111/1752-1688.13061.

Salehabadi, H., D. Tarboton, E. Kuhn, B. Udall, K. Wheeler, D. Rosenberg, S. Goeking and J. C. Schmidt, (2020), "The Future Hydrology of the Colorado River Basin," Center for Colorado River Studies, White Paper 4, Utah State University, https://qcnr.usu.edu/coloradoriver/files/WhitePaper4.pdf.

U.S. Bureau of Reclamation, (2023), Colorado River Basin Natural Flow and Salt Data, Colorado River Basin Natural Flow Database. Last updated December 15, 2022, https://www.usbr.gov/lc/region/g4000/NaturalFlow/current.html