| To the right is the
2000 version of the regulation. The text in paragraph a is
the current version of the text quoted by the engineer. However, the
text in paragraph b specifies that there are times when the
mean annual high water line is higher than the first observable break
in slope. Specifically, this occurs when the river is "characterized
by at least two of the following features: low gradient, meanders,
oxbows, histosols, a low-flow channel, or poorly-defined or nonexistent
banks." Of these six characteristics, the Housatonic at this
location shows five (low gradient, meanders, oxbows, histosols, low
flow channel). In this situation, the mean annual highwater line "is
represented by bankfull field indicators." These
indicators "include but are not limited to: changes in slope,
changes in vegetation, stain lines, top of pointbars, changes in bank
materials, or bank undercuts."In looking at these indicators,
regulators are trying to determine the level to which the river can
be expected to rise each spring. Field signs, including those mentioned
in the regulations, indicate that the river at this site rises much
higher than indicated by the engineer. In fact, neighbors report that
the river regularly floods onto their properties. |
|
310 CMR: DEPARTMENT OF ENVIRONMENTAL PROTECTION
10.58: continued 2. Mean Annual High-Water
Line of a river is the line that is apparent from visible markings
or changes in the character of soils or vegetation due to the prolonged
presence of water and that distinguishes between predominantly aquatic
and predominantly terrestrial land. Field indicators of bankfull conditions
shall be used to determine the mean annual high-water line. Bankfull
field indicators include but are not limited to: changes in slope,
changes in vegetation, stain lines, top of pointbars, changes in bank
materials, or bank undercuts.
a. In most rivers, the first observable
break in slope is coincident with bankfull conditions and the
mean annual high-water line.
b. In some river reaches, the mean
annual high-water line is represented by bankfull field indicators
that occur above the first observable break in slope, or if no
observable break in slope exists, by other bankfull field indicators.
These river reaches are characterized by at least two of the following
features: low gradient, meanders, oxbows, histosols, a low-flow
channel, or poorly-defined or nonexistent banks.
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