Elevation-Derived Hydrography READ Rules: Reservoir
A Reservoir is a constructed basin formed to contain water or other liquids.
Attribute/Attribute Value
Each feature requires domain codes to be entered into the attribute table for the feature class (EDH Feature type description, associated geometry, and use classification table). See “Field Definitions and Domain Values for Attributes” section for more information on EDH code definitions.
Delineation
The limit of reservoir is the rim of the constructed basin.
Representation Rules
When delineating a feature, it must be created with the appropriate geometry, either point, line, or polygon, which is determined by the size of the feature or the length along different axes of the feature (table 16).
Special conditions: none.
Table 16. Reservoir Representation Rules.
|
Kind of feature object |
Area |
Shortest Axis |
Longest Axis |
|
0-dimensional (point) |
-- |
-- |
-- |
|
1-dimensional (line) |
-- |
-- |
-- |
|
2-dimensional (polygon) |
greater than 0 |
-- |
-- |
Data Extraction
Capture Conditions
For required lidar base specification hydroflattening breakline acquisition, waterbodies with a surface area of 2 acres (8,000 square meters) or greater at the time of collection shall be flattened.
For EDH feature collection, if the reservoir is greater than or equal to 0.25 acres (or approximately 1,000 square meters), then capture.
Attribute Information
FClass 1—NHD Feature (will be used for conflation).
FCode 43600—Reservoir (a constructed basin formed to contain water or other liquids. Function or purpose of reservoir is unknown. Predominant construction material used to build the reservoir is unknown. The portion of the year the feature contains water is unknown).
EClass 1—Use for hydroflattening (3D polygon).
Source Interpretation Guidelines
Refer to the feature definition to decide how to categorize a given feature instance. Do not use the proper name of the feature as a guide. Many features that are known as “Reservoirs” or labeled on the topographic map as “Reservoirs” will be captured as lake/ponds. “Stock Tanks” may be reservoir or lake/pond depending on their form. As a general rule, if a waterbody has a geometric shape or other information indicates it is contained by a constructed basin, capture it as reservoir. If it does not appear to be contained by a constructed basin, capture it as lake/pond.
If reservoir is
less than 100 feet along the shortest axis and is within 40 feet of another reservoir with the same attribute values,
then capture as one reservoir only if the combined areas are greater than or equal to 1 acre (4000 square meters).
For lidar base specification hydroflattening, permanent islands 1 acre (4,000 square meters) or larger shall be delineated within all waterbodies.
For examples of islands and intermittently submerged islands that may be apparent on elevation surface, see “Additional EDH Related Treatments and Elevation Specific Features” section.
