Water Chemistry Field Sampling
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certain stream orders * or otherwise constrained according to watershed area,
elevation, presence/absence of fish, or presence or absence of watershed disturbance. For nonrandom surveys, intended to identify and characterize the most
acid-sensitive surface waters in a specific region, forest, or wilderness, we typically recommend particular focus on the following types of lakes and streams:
• perched seepage lakes
• small (less than about 50 to 100 ha) drainage lakes occupying relatively high landscape position and having average depth greater than
about 1 m †
• low-order streams (first through third order)
In some cases, a systematic approach to preselection of sampling sites may
reduce the number of candidate sites to such a degree that all or most of the
high-interest candidate sites can be sampled.
2.2.1.2 Selection of Specific Sampling Sites
The sampling site in a lake is generally selected on the basis of logistical considerations. The preferred site is the deepest portion of the lake, but this requires
use of a boat, raft, or float tube. If it is not possible to sample at the deepest portion of the lake, then an alternative site can be the lake outlet or (least desirable
of the three) a shoreline location.
* Stream order refers to a system of classifying streams based on their branching pattern. The
smallest-headwater streams are first order. When two first-order streams come together, they
form a second-order stream. As more first-order streams flow into the second-order stream,
its order is not affected; it is still second order. When two second-order streams combine, it
becomes third order. The process continues to progressively higher orders. The scale of the
mapped data used to designate stream order has influence on the classification. Most acidsensitive streams tend to be relatively low order (often first through third order at 1:100,000
scale or first through fourth order at higher resolution).
† Lakes that are less than about 1 m deep grade into wetlands. Some studies of lakes only include
those deeper than 1 m.
SEEPAGE LAKES
Seepage lakes are lakes that do not have either inlet or outlet streams.
There are two general types. Perched seepage lakes are raised above
the surrounding terrain, often by buildup of organic deposits; they
are often precipitation dominated in their hydrology. Flow-through
seepage lakes receive considerable groundwater inputs and generally have higher ANC and silicon (Si) concentrations than do perched
seepage lakes.
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certain stream orders * or otherwise constrained according to watershed area,
elevation, presence/absence of fish, or presence or absence of watershed disturbance. For nonrandom surveys, intended to identify and characterize the most
acid-sensitive surface waters in a specific region, forest, or wilderness, we typically recommend particular focus on the following types of lakes and streams:
• perched seepage lakes
• small (less than about 50 to 100 ha) drainage lakes occupying relatively high landscape position and having average depth greater than
about 1 m †
• low-order streams (first through third order)
In some cases, a systematic approach to preselection of sampling sites may
reduce the number of candidate sites to such a degree that all or most of the
high-interest candidate sites can be sampled.
2.2.1.2 Selection of Specific Sampling Sites
The sampling site in a lake is generally selected on the basis of logistical considerations. The preferred site is the deepest portion of the lake, but this requires
use of a boat, raft, or float tube. If it is not possible to sample at the deepest portion of the lake, then an alternative site can be the lake outlet or (least desirable
of the three) a shoreline location.
* Stream order refers to a system of classifying streams based on their branching pattern. The
smallest-headwater streams are first order. When two first-order streams come together, they
form a second-order stream. As more first-order streams flow into the second-order stream,
its order is not affected; it is still second order. When two second-order streams combine, it
becomes third order. The process continues to progressively higher orders. The scale of the
mapped data used to designate stream order has influence on the classification. Most acidsensitive streams tend to be relatively low order (often first through third order at 1:100,000
scale or first through fourth order at higher resolution).
† Lakes that are less than about 1 m deep grade into wetlands. Some studies of lakes only include
those deeper than 1 m.
SEEPAGE LAKES
Seepage lakes are lakes that do not have either inlet or outlet streams.
There are two general types. Perched seepage lakes are raised above
the surrounding terrain, often by buildup of organic deposits; they
are often precipitation dominated in their hydrology. Flow-through
seepage lakes receive considerable groundwater inputs and generally have higher ANC and silicon (Si) concentrations than do perched
seepage lakes.