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1 Variables Description for INDOFLOODS: A Comprehensive Database for Flood Events in India Enhanced with Catchment Attributes Sai Kiran Kuntla1 and Manabendra Saharia1,2 1Department of Civil Engineering, Indian Institute of Technology Delhi, Hauz Khas, New Delhi 110016, India 2Yardi School of Artificial Intelligence, Indian Institute of Technology Delhi, Hauz Khas, New Delhi 110016, India Contents of this file Table 1: Information provided in the metadata of the database. Table 2: Description of flood-event variables contributing to the database. Table 3: List of catchment-scale variables provided in the database.
2 Table 1: Information provided in the metadata of the database. Field Description GaugeID A unique ID is assigned to each gauge station, such as “INDOFLOODS-gauge1”, for easy identification and representation among various subsets of this database. Warning Level The level of the streamflow (mtr) above which the streamflow is classified as “Flood”. Danger Level The level of the streamflow (mtr) above which the streamflow is classified as a “Severe Flood”. Station Name of the station Latitude and Longitude The geographical coordinates of the gauge station. River Name The name of the river on which the gauge station is installed. The tributary and sub-tributary name(s) are also provided wherever available. Basin The name of the Basin in which the gauge station lies. Names of the basin are as per the records of CWC. Start date Date of the oldest record of streamflow data available based on which the flood events in INDOFLOODS are extracted. All dates conform to ISO 8601 (YYYYMM-DD), the international standard for representing dates and times. End date Date of the latest record of streamflow data available based on which the flood events in INDOFLOODS are extracted. All dates conform to ISO 8601 (YYYYMM-DD), the international standard for representing dates and times. Level Entries Number of stream level data entries available between the “Start date” and “End date” Streamflow Entries Number of stream discharge data entries available between the “Start date” and “End date” Privacy Indicates if the source streamflow data is classified or unclassified using the terms “Open” and “Restricted”. Unclassified is open to all users by the CWC and free
3 of charge. In comparison, the classified data is restricted and provided only on request. Source catchment area The upstream catchment area of the gauge station as per the documents of CWC. Shapefile catchment area The upstream catchment area of the gauge station, which was computed using the shapefile developed and provided through the INDOFLOODS database. Area variation The percentage of variation between “Source catchment area” and “Shapefile catchment area”. Shapefile reliability “Safe” if the “Area variation” is less than 25 percent, and “Caution” if the “Area variation” is more than 25 percent. Also, a shapefile is classified as “Caution” if the “Source catchment area” is unavailable.
1 Table 2: Description of flood-event variables contributing to the database. Variable Description EventID It is the unique ID corresponding to the flood event in an extensible format such as INDOFLOODS-gauge-118-10, where “INDOFLOODS-gauge-118” is the gauge ID (from metadata) of the gauge station where the respective flood event has been observed, and “10” is for the serial number of the event at that station. This schema makes it flexible enough to incorporate future events and connect them with metadata and other datasets. Start Date Start date of the flood event - when the flow exceeds the flooding threshold (warning level). All dates conform to ISO 8601 (YYYY-MM-DD), the international standard for representing dates and times. End Date End date of the flood event - when the flow dropped below the flooding thresholds (warning level). Peak flood level Peak flood level corresponding to that event. Peak flood level Date The corresponding date of occurrence of the “Peak flood level”. Number of Peak flood level The number of times (days) the flow has touched the peak flood level in the same event. Peak Discharge The magnitude of the peak discharge corresponding to that event. Peak Discharge Date The corresponding date of occurrence of the “Peak discharge”. Flood Volume The total discharge of the flood event. It equals the sum of daily discharge over all the days of a flood event. Event Duration The total number of days the flood lasted.
2 Time to peak The total number of days it took to reach the peak of flood level from start time. Recession time The total number of days it took from the peak of flood level to end time. Flood type Specifies whether the event is a ‘Flood’ or ‘Severe Flood’. If the Peak flood level of the corresponding event is above the “Danger level,” it is a “Severe Flood”. Otherwise, “Flood”.
1 Table 3: List of catchment-scale variables provided in the database. Catchment Characteristics Description Reference Geomorphology Stream order (SO) Strahler stream order, numerical measure of river’s branching complexity (Strahler, 1952) Drainage area (DA) The surface area of the catchment Catchment magnitude (CM) The number of first order streams (Melton, 1957) Maximal flow length (MFL) the length along the longest watercourse from the mouth to the head of the channel (Mueller, 1968) Downvalley length (DVL) The straight distance from the river cell of interest to the basin mouth (Mueller, 1968) Catchment relief (CR) The elevation difference between the highest point on the drainage divide and the mouth (Costa, 1987) Catchment length (CL) The maximal length of the line from a basin mouth to a point on the perimeter equidistant from the basin mouth in either direction around the perimeter (Gregory & Walling, 1968) Catchment perimeter (CP) The length of outer boundary of the watershed that enclosed its area (Schumm, 1956) Sinuosity index (SI) SI = MFL/DVL (Wolman & Miller, 1960) Form factor (FF) FF = DA/CL2 (Horton, 1945) Relief ratio (RR) RR = CR/CL (Schumm, 1956)
2 Elongation ratio (ER) ER = 2/(CL x (DA/𝜋)0.5) (Schumm, 1956) Circularity ratio (CR) CR = 4 𝜋DA/CP2 (Miller & Summerson, 1960) Lemniscates value (LV) LV = CL2/DA (Chorley, 1957) Drainage texture (DT) DT = Total number of streams of all order/CP (Horton, 1945) Drainage density (DD) DD = Total length of streams of all orders/DA (Horton, 1945) Compactness coefficient (CC) CC = 0.2841 (CP/DA0.5) (Gravelius, 1914) Wandering ratio (WR) MFL/CL (Smart & Surkan, 1967) Fitness ratio (FR) MFL/CP (Melton, 1957) Channel frequency (CF) CF = Total number of streams of all orders/DA (Horton, 1932) Drainage intensity (DI) CF/DD (Faniran, 1968) Infiltration number (IN) CF x DD (Faniran, 1968) Ruggedness number (RN) CR x DD (Strahler, 1964) No. of streams by order Number of first, second, third fourth, fifth, sixth, seventh, and eighth-order streams in the catchment. (Horton, 1945)
3 Total length of streams by order (SL) Total length of first, second, third, fourth, fifth, sixth, seventh, and eighth-order streams in the catchment. (Horton, 1945) Mean length of streams by order (MSL) Mean length of first, second, third, fourth, fifth, sixth, seventh, and eighth-order streams in the catchment. (Strahler, 1964) Stream length ratio (SLR) Ratio between the total length of streams of a given order to the number of streams of the next higher order. (Horton, 1945) Bifurcation ratio (BR) Ratio between the number of streams of a given order to the number of streams of the next higher order. (Schumm, 1956) Climatological Annual mean temperature (Bio1) The annual mean temperature (Fick & Hijmans, 2017) Mean diurnal range (Bio2) The mean of the monthly temperature ranges (monthly maximum minus monthly minimum) Isothermality (Bio3) Isothermality quantifies how large the dayto-night temperatures oscillate relative to the summer-to-winter (annual) oscillations. Bio3= (Bio2/Bio7)x100 Temperature seasonality (Bio4) The amount of temperature variation over a given year (or averaged years) based on the standard deviation (variation) of monthly temperature averages. Maximum temperature of The maximum monthly temperature occurrence over a given year (time-series) or averaged span of years (normal).
4 warmest month (Bio5) Minimum temperature of coldest month (Bio6) The minimum monthly temperature occurrence over a given year (time-series) or averaged span of years (normal). Temperature annual range (Bio7) A measure of temperature variation over a given period. Bio7=Bio5-Bio6 Mean temperature of wettest Quarter (Bio8) This quarterly index approximates mean temperatures that prevail during the wettest season. Mean temperature of driest quarter (Bio9) This quarterly index approximates mean temperatures that prevail during the driest quarter. Mean temperature of warmest quarter (Bio10) This quarterly index approximates mean temperatures that prevail during the warmest quarter. Mean temperature of coldest quarter (Bio11) This quarterly index approximates mean temperatures that prevail during the coldest quarter. Annual precipitation (Bio12) This is the sum of all total monthly precipitation values. Precipitation of wettest month (Bio13) This index identifies the total precipitation that prevails during the wettest month.
11 (1975-1990-2000-2015). European Commission, Joint Research Centre (JRC). http://data.europa.eu/89h/jrc-ghsl-ghs_smod_pop_globe_r2016a Schumm, S. A. (1956). Evolution of drainage systems and slopes in badlands at Perth Amboy, New Jersey. GSA Bulletin, 67(5), 597–646. https://doi.org/10.1130/00167606(1956)67[597:EODSAS]2.0.CO;2 Smart, J. S., & Surkan, A. J. (1967). The relation between mainstream length and area in drainage basins. Water Resources Research, 3(4), 963–974. Scopus. https://doi.org/10.1029/WR003i004p00963 Strahler, A. N. (1952). Dynamic Basis of Geomorphology. GSA Bulletin, 63(9), 923–938. https://doi.org/10.1130/0016-7606(1952)63[923:DBOG]2.0.CO;2 Strahler, A. N. (1964). Quantitative Geomorphology of Drainage Basins and Channel Networks. McGraw Hill. Tang, G., Clark, M. P., & Papalexiou, S. M. (2022). EM-Earth: The Ensemble Meteorological Dataset for Planet Earth. Bulletin of the American Meteorological Society, 103(4), E996– E1018. https://doi.org/10.1175/BAMS-D-21-0106.1 The Climate Change Initiative Land Cover (CCI-LC). (n.d.). ESA/CCI Viewer. Retrieved April 15, 2022, from https://maps.elie.ucl.ac.be/CCI/viewer/ Wolman, M. G., & Miller, J. P. (1960). Magnitude and Frequency of Forces in Geomorphic Processes. The Journal of Geology, 68(1), 54–74. https://doi.org/10.1086/626637
