Lakes fields

Descriptions of the fields in the lakes feature class.

Field	Alias	Description
GOID	Global object identifier	Corresponds to the GOID of the river. For the model to recognize the river in the river network where the lake is located, each lake must have the correct GOID (i.e., the GOID that corresponds to the GOID of the river reach).
GOOD	Included in GOODD database	A binary field indicating if Lake is a reservoir identified in GOODD database
Lake_type	Type of lake	Indicator for lake type: 1: Lake 2: Reservoir 3: Lake control (i.e. natural lake with regulation structure)
SED_ACC	Sediment accumulation	Erosion yield (tons / year).
IN_STREAM	In stream network	A binary field indicating if the lake is connected to the stream network (value = 1) or not connected (value = 0)
IN_CATCH	Inside catchment	A binary field indicating if the lake is in a catchment of the stream network (value = 1) or not in a catchment of the stream network (value = 0).
OUT_CATCH	Outside catchment	A binary field indicating whether the lake is outside of a stream catchment (value = 1) or inside a stream catchment (value = 0). This filed is the opposite of the IN_CATCH field.
Dis_avg	Average discharge	Average long-term discharge flowing through the lake, in cubic meters per second. This value is derived from modeled runoff and discharge estimates provided by the global hydrological model WaterGAP, downscaled to the 15 arc-second resolution of HydroSHEDS (see section 2.2 for more details) and is extracted at the location of the lake pour point. Note that these model estimates contain considerable uncertainty, in particular for very low flows. -9999: no data as lake pour point is not on HydroSHEDS landmask.
Res_time	Residence time	Average residence time of the lake water, in days. The average residence time is calculated as the ratio between total lake volume (‘Vol_total’) and average long-term discharge (‘Dis_avg’). Values below 0.1 are rounded up to 0.1 as shorter residence times seem implausible (and likely indicate model errors). -1: cannot be calculated as ‘Dis_avg’ is 0 -9999: no data as lake pour point is not on HydroSHEDS landmask
Hylak_id	Hylak identifier	Unique lake identifier.
Lake_name	Lake name	Name of lake or reservoir. This field is currently only populated for lakes with an area of at least 500 km2; for large reservoirs where a name was available in the GRanD database; and for smaller lakes where a name was available in the GLWD database.
Country	Country name	Country that the lake (or reservoir) is located in. International or transboundary lakes are assigned to the country in which its corresponding lake pour point is located and may be arbitrary for pour points that fall on country boundaries.
Continent	Continent name	Continent that the lake (or reservoir) is located in. Geographic continent: Africa, Asia, Europe, North America, South America, or Oceania (Australia and Pacific Islands).
Poly_src	Polygon source	Source of original lake polygon: CanVec; SWBD; MODIS; NHD; ECRINS; GLWD; GRanD; or Other.
Lake_area	Lake area	Lake surface area (i.e. polygon area), in square kilometers.
Shore_len	Length of shoreline	Length of shoreline (i.e. polygon outline), in kilometers.
Shore_dev	Shore development	Shoreline development, measured as the ratio between shoreline length and the circumference of a circle with the same area. A lake with the shape of a perfect circle has a shoreline development of 1, while higher values indicate increasing shoreline complexity.
Vol_total	Total volume	Total lake or reservoir volume, in million cubic meters (1 mcm = 0.001 km3). For most polygons, this value represents the total lake volume as estimated using the geostatistical modeling approach by Messager et al. (2016). However, where either a reported lake volume (for lakes ≥ 500 km2) or a reported reservoir volume (from GRanD database) existed, the total volume represents this reported value. In cases of regulated lakes, the total volume represents the larger value between reported reservoir and modeled or reported lake volume. Column ‘Vol_src’ provides additional information regarding these distinctions.
Vol_res	Volume residence	Reported reservoir volume, or storage volume of added lake regulation, in million cubic meters (1 mcm = 0.001 km3).
Vol_src	Volume source	The data source for the reservoir volume. 0: no reservoir volume 1: ‘Vol_total’ is the reported total lake volume from literature 2: ‘Vol_total’ is the reported total reservoir volume from GRanD or literature 3: ‘Vol_total’ is the estimated total lake volume using the geostatistical modeling approach by Messager et al. (2016)
Depth_avg	Average depth	Average lake depth, in meters. Average lake depth is defined as the ratio between total lake volume (‘Vol_total’) and lake area (‘Lake_area’).
Elevation	Elevation	Elevation of lake surface, in meters above sea level.
Slope_100	Slope over 100 metres	Average slope within a 100 meter buffer around the lake polygon, in degrees.
Wshd_area	Watershed area	Area of the watershed associated with the lake, in square kilometers. The watershed area is calculated by deriving and measuring the upstream contribution area to the lake pour point using the HydroSHEDS drainage network map at 15 arc-second resolution. -9999: no data as lake pour point is not on HydroSHEDS landmask.
Pour_long	Pour longitude	Longitude of the lake pour point, in decimal degrees.
Pour_lat	Pour latitude	Latitude of the lake pour point, in decimal degrees.