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CHAPTER 4 - MAPPING RIPARIAN AREAS
Contents
CHAPTER 4 - MAPPING RIPARIAN AREAS ........................................................................ 1
Contents ...................................................................................................................................... 1
CHAPTER 4 - MAPPING RIPARIAN AREAS ................................................................ 2
4.02 - Objective. ...................................................................................................................... 2
4.1 – Mapping Standards ............................................................................................................ 2
4.11 - Map Scale. .................................................................................................................... 2
4.12 - Unit Size. ...................................................................................................................... 2
4.13 - Unit Complexity. .......................................................................................................... 3
4.14 - Map Symbols. ............................................................................................................... 3
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CHAPTER 4 - MAPPING RIPARIAN AREAS
4.02 - Objective.
At any planning level, it is neither possible nor appropriate to describe every feature. Mapping
standards help achieve quality mapping at an appropriate level of precision. Mapping standards
must:
1. Aggregate data consistently.
2. Avoid confusion caused by excessive detail.
3. Reduce map errors caused by large relative line widths.
These three objectives are especially crucial when mapping units of riparian areas due to their
long, narrow shape. To achieve these objectives, apply the following standards. The substantial
generalization required for planning will usually warrant considerable aggregation of these units
to create maps of analysis and management areas.
4.1 – Mapping Standards
4.11 - Map Scale.
For Regional planning, map at a 1:250,000 or more detailed scale. For Forest planning, map at
the R-3 standard of 1:24,000 or a more detailed scale. Consider using more detailed scales for
project plans.
4.12 - Unit Size.
1. Width: Map a unit as an area only if its map width equals or exceeds 0.1 inch. This
equates to about 2,080 feet at 1:250,000 scale and 200 feet at a 1:24,000 scale. Map narrower
units, commonly found along ephemeral streams, as a line.
2. Length: Map a unit along a channel only if its map length equals or exceeds 0.5 inch.
This equates to about 10,400 (1.97 miles) feet at a 1:250,000 scale and 1,000 feet (0.19 miles) at
a 1:24,000 scale. Map shorter units as inclusions in upstream or downstream units.
3. Area: Map a unit as an area only if its map area equals or exceeds 0.05 square inch.
This equates roughly to a square 0.22 inches per side or a circle with a diameter of 0.5 inches.
This equals about 500 acres at a 1:250,000 scale and 4.6 acres at a 1:24,000 scale. Map smaller
units as inclusions in upstream or downstream units or as labeled points.
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4.13 - Unit Complexity.
For Regional and Forest planning, map only full-width segments of riparian areas. Split the
width of narrow areas only for detailed project plans.
4.14 - Map Symbols.
Mapped riparian areas will usually form lines or long, narrow areas. They will usually comprise
combinations of land and water, making use of traditional map symbols inappropriate. As a
minimum, use the following standard coding system for identifying riparian map units.
At the Regional level, map only vegetation biomes. Use the biome codes shown in section 3.31,
exhibit 1, for map unit symbols. For example, the code 5.0 identifies a riparian area in the
Deciduous or Mixed Evergreen---Deciduous forest (cold temperate forest).
At the Forest level, use all four description components (exhibit 1).
Map Unit Code = VFRP, where
V = Vegetation Biome and Series
F = Valley Form
R = Water Regime
P = Water Permanance
Identify the vegetation using numerical biome and series codes (section 3.31, exhibit 1). Identify
valley form, water regime, and water permanence through letter codes (sections 3.32 through
3.34). For example the code 5.103 qmi identifies the unit as (1) within the Deciduous or Mixed
Evergreen-Deciduous forest, vegetated by the Populus angustifolia series, (2) located in a gentle
valley, (3) along a medium stream, (4) of interrupted permanence (exhibit 2).
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Exhibit 1
COMPOSITION OF A RIPARIAN MAPPING UNIT (FOREST LEVEL)
V = VEGETATION BIOME AND SERIES
1.505
2.003
3.314
3.323
3.311
4.001
4.011
5.103
6.335
7.130
7.104
8.350
8.351
Salix artica
Abies lasiocarpa
Salix glauca
Alnus tenuifolia
Potentilla fruticosa
Abies concolor
Picea pungesn
Populus angustifolia
Salix bebbiana
Platanus wrightii
Populus fremontii
Baccaris glutinosa
Chrysothamnus nauseosus
8.352
9.131
9.132
10.733
10.734
10.735
11.415
11.460
11.507
11.429
11.423
Fallugia paradoxa
Populus fremontii-Salix
bonplandiana
Prosopis juliflora
Prosopis juliflora-Olneya
tesota
Hymenoclea spp.
Tamarix chinensis
Deschampsia caespitosa
Carex nebraskensis
Typha latifolia
Sporobolus airioloes
Juncus acuminatus
Exhibit 1
SEE THE PAPER COPY OF THE MASTER SET
FOR SECTION 4.14 - EXHIBIT 1
Exhibit 2
SEE THE PAPER COPY OF THE MASTER SET
FOR SECTION 4.14 - EXHIBIT 2