Ministry of Environment

Fisheries InventoryFisheries Inventory

Lake Survey Data Definitions

Watershed Code — A series of groups of digits separated by dashes that uniquely identifies watersheds (a stream and the surrounding land that drains into the stream) in British Columbia. Each group of digits represents an unique watershed and shows the hierarchy from the ocean to the identified watershed. A watershed has a single mainstem, so the watershed code uniquely identifies streams, as well as the watershed.

Waterbody Identifier - A unique code used to identify every waterbody in the province. It consists of a 5 digit computer-generated number followed by the 4 character coverage code of the parent watershed group.

Gazetted Name — The legally registered name of the lake as obtained from Geographic Data B.C.

Region - The Ministry of Environment administrative area

Survey Date - Day/Month/Year that the survey was conducted.

Agency Name - Name of the government agency or consulting firm that collected the data.

Surface Area - The wetted area of the lake, excluding islands, in hectares at the time of the survey as calculated from a bathymetric map. Most surveys include wetlands surrounding the lake, but some may not. Some surveys may treat two or more small lakes as a single unit and the single surface area represents all the lakes surveyed. Surveys are done at different times of the year and over many years. A particular surface area measurement may have been taken during the spring runoff after a high snowfall winter or in late summer after several drought years. Also, the methods of calculating surface have improved over the years.

Littoral Area - The surface area, in hectares, of that part of the lake extending from the shoreline that is less than 6 metres deep at the time of the survey as determined from a bathymetric map. The value for littoral area given for surveys prior to 1981 may be inaccurate. In many cases the calculation for pelagic area (greater than 6 metres depth) was entered instead. This is beiong investigated and erroneous values corrected. Until that is complete, littoral areas in surveys prior to 1981 should be treated as suspect and verified before being used.

Perimeter - The distance around the lake, excluding islands, in metres as calculated from a bathymetric map.

Volume - The total water volume, in cubic metres, of the lake as calculated from a bathymetric map.

Mean Depth - An average of lake depth measurements, in metres, at the time of the survey as calculated from a bathymetric map.

Max. Depth - The maximum depth of the lake, in metres, at the time of the survey.

Outlets - The number of streams flowing out of the lake, both permanent and intermittent, observed at the time of the survey.

Permanent Inlets - The number of streams flowing into the lake year-round.

Alias — One of the, possibly many, locally used names for a waterbody.

PH - A measurement of the acidity of the lake, taken at the surface, at the time of the survey. A surface pH is provided as measured in a laboratory or in the field.

TDS - Total Dissolved Solids or non-filterable residue of the lake, in parts per million, at the time of the survey. A surface TDS is provided as measured in a laboratory or in the field.

Hydrogen Sulfide - A yes/no field indicating that H2S was either present or absent in the lake at the time of the survey.

Secchi Depth - An estimate of turbidity determined by lowering a striped disk into a lake until it is no longer visible and recording the depth in metres.

Cloud Cover - An estimate of cloud cover on a 0 to 10 scale where 0 is clear.

Special Sampling - This field indicates if any special water, fish plant or bottom samples were taken during the survey.

Species - The common name of the fish.