The process of determining annual recession rates shall include
preparation of recession-line base maps, measurement of recession distances on
the recession-line maps, and calculation of annual recession rates.
(A) Recession-line maps shall be prepared
using the following procedure.
(1) Base maps
shall be constructed using the most currently available imagery. Types of
base-map imagery may include, but are not limited to, aerial photographs,
remote sensing imagery, digital data, or some combination thereof. Criteria
used to select base-map imagery shall include, but are not limited to, complete
synoptic coverage of the Ohio shore where the shore is centrally located on the
images, adequate geographic reference points, and resolution that is adequate
to map a base recession line and identify cultural and physiographic features
on the imagery.
(2) The resulting
base maps shall be produced at a nominal scale of one inch equal to two hundred
feet; the scale of the base maps shall be verified with field measurements not
less than five hundred feet in length, and the true scale in feet shall be
noted on each individual base map.
(3) A base recession line shall be mapped on
the recession-line base maps as described in paragraph (R) of rule
1501-6-10 of the
Administrative Code.
(4)
Historical imagery used to prepare recession-line maps shall be selected from
charts, aerial photographs, or other imagery of the shore which are on file at
the department of natural resources, division of geological survey. Criteria
used to select this imagery for recession-line mapping shall include but are
not limited to those criteria listed in paragraph (A)(1) of this rule. Imagery
shall be acquired within a time period of not less than ten years nor greater
than thirty years prior to the year that the base-map imagery was acquired.
(5) Recession lines from charts,
aerial photographs, or other imagery shall be projected or digitally
transferred onto the base maps.
(B) Recession distances shall be measured at
points uniformly spaced along the base recession line. The recession distance
at each point shall be measured from the base recession line along a transect
oriented at a right angle to the general trend of the base recession line
(figure 1). Each transect shall be uniquely identified and the measured
recession distance shall be recorded and used to calculate the annual recession
rate.
See Figure 1 at
http://www.registerofohio.state.oh.us/pdfs/1501/0/6/1501-6-11_PH_FYR_C_RU_20090729_1320.pdf
FIGURE 1: EXAMPLE ILLUSTRATING BASE-RECESSION LINE, TRANSECT
ORIENTATION, AND UNIFORM SPACING BETWEEN TRANSECTS.
(C) For each transect, the annual recession
rate in feet per year shall be calculated by dividing the measured recession
distance by the time period in years between the recession lines. The minimum
annual recession rate shall be zero feet per year.
R.C. 119.032 review dates: 07/29/2009
and 07/25/2014
