Geoscience Reference
In-Depth Information
MRLC Classification Scheme and Class Definitions
The MRLC program utilizes a consistent classification scheme for all EPA regions at approx-
imately an Anderson Level II thematic detail. While there are 21 classes in the MRLC system, only
15 were mapped in EPA Region IV. The following classification scheme was applied to the EPA
Region IV data set:
1.0
Water: All areas of open water or permanent ice/snow cover.
1.1
Water: All areas of open water, generally with less than 25% vegetation.
2.0
Developed: Areas characterized by a high percentage of construction materials (e.g., asphalt,
concrete, buildings, etc.).
2.1
Low-intensity residential: Land includes areas with a mixture of constructed materials and
vegetation or other cover. Constructed materials account for 30 to 80% of the total area.
These areas most commonly include single-family housing areas, especially suburban neigh-
borhoods. Generally, population density values in this class will be lower than in high-
intensity residential areas.
2.2
High-intensity residential: Includes heavily built-up urban centers where people reside.
Examples include apartment complexes and row houses. Vegetation occupies less than 25%
of the landscape. Constructed materials account for 80 to 100% of the total area. Typically,
population densities will be quite high in these areas.
2.3
High-intensity commercial/industrial/transportation: Includes all highly developed lands not
classified as “high-intensity residential,” most of which is commercial, industrial, and
transportation.
3.0
Barren: Bare rock, sand, silt, gravel, or other earthen material with little or no vegetation regardless
of its inherent ability to support life. Vegetation, if present, is more widely spaced and scrubby
than that in the vegetated categories.
3.1
Bare Rock/Sand: Includes areas of bedrock, desert pavement, scarps, talus, slides, volcanic
material, glacial debris, beach, and other accumulations of rock and/or sand without vege-
tative cover.
3.2
Quarries/strip mines/gravel pits: Areas of extractive mining activities with significant surface
expression.
3.3
Transitional: Areas dynamically changing from one land cover to another, often because of
land use activities. Examples include forestlands cleared for timber and may include both
freshly cleared areas as well as areas in the earliest stages of forest growth.
4.0
Natural forested upland (nonwet): A class of vegetation dominated by trees generally forming >
25% canopy cover.
4.1
Deciduous forest: Areas dominated by trees where 75% or more of the tree species shed
foliage simultaneously in response to an unfavorable season.
4.2
Evergreen forest: Areas dominated by trees where 75% or more of the tree species maintain
their leaves all year. Canopy is never without green foliage.
4.3
Mixed forest: Areas dominated by trees where neither deciduous nor evergreen species
represent more than 75% of the cover present.
5.0
Herbaceous planted/cultivated: Areas dominated with vegetation that has been planted in its current
location by humans and/or is treated with annual tillage, modified conservation tillage, or other
intensive management or manipulation. The majority of vegetation in these areas is planted and/or
maintained for the production of food, fiber, feed, or seed.
5.1
Pasture/hay: Grasses, legumes, or grass-legume mixtures planted for livestock grazing or
the production of seed or hay crops.
