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GENERAL51571
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Last modified
8/24/2016 8:37:46 PM
Creation date
11/23/2007 6:55:55 PM
Metadata
Fields
Template:
DRMS Permit Index
Permit No
M1986165
IBM Index Class Name
General Documents
Doc Date
12/3/2003
Doc Name
Channel Geomorphology Issues
From
Mary L.Gillam Ph.D.
To
U.S.Army Corps of Engineers
Permit Index Doc Type
General Correspondence
Media Type
D
Archive
No
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• Because these surveys were conducted after spring high flows, they probably do not show <br />the maximum lowering of the river bed at the end of each mining season, as later spring <br />flows would likely have deposited gravel on many parts of the river bed. In the gravel <br />mining industry and among scientists, this high-flow period is considered to be the time <br />when most annual replenishment of gravel occurs; therefore, it seems ill-reasoned or <br />deceptive for the operator to use ]ate-summer to eazly winter surveys as a measure of <br />previous mining compliance; surveys performed then would make the previous mining <br />operations appeaz more compliant with the mining depth limit than they actually may <br />have been (see also Section 3.5 below). <br />• Some survey data appear incomplete or unrealistic; for example, broad, flat inverts may <br />correspond to the water surface, not the underlying thalweg; Greg Lewicki (of Greg <br />Lewicki and Associates, consultant to Four Comers Materials) has stated that all of the <br />inverts surveyed in 2001 and eazlier yeazs may have shown the water surface, not the <br />channel bottom (oral statement to Mary Gillam, 7/25/03); possibly repeated surveys did <br />not follow the same alignment and some topographic inflection points were not surveyed <br />(Paul Sugnet to Lesley McWhirter, 11/12/02); and one survey appears consistently too <br />low, as if the data were entered incorrectly into the plotting soflwaze. <br />• In longitudinal profiles, sections were plotted at along-channel distances in 1996 and <br />selected channel bed elevations were shown numerically. <br />• It is not cleaz whether the longitudinal profiles were drawn in a consistent, logical way; <br />selected channel bed elevations are shown numerically on these profiles, but in some <br />cases the line was drawn above those elevations, or the lowest elevation in the cross <br />section was not used for the longitudinal profile (profile construction methods are not <br />described in the reports). <br />• Maps showed the cross section locations in relation to the channel pattern that existed <br />when the cross sections were surveyed. <br />• Monitoring reports have not always been provided in a timely manner; one was submitted <br />more than a yeaz after the associated surveys were done; and the report presenting data <br />for January and July of 2003 is expected in February, 2004, after the decision about <br />extending the permit will already have been made (Paul Sugnet to Kaza Hellige, <br />10/16/03). <br />• The promised off-site cross sections were never established. Cross sections at <br />downstream pits fulfilled that need, but an upstream section would have provided new <br />and valuable information. <br />3.4 Compliance with Mining Requirements <br />During the first mining season after the permit was signed, Burnett probably mined below <br />the 1996 low flow channel level before receiving permission to do so from USACE; this <br />conclusion is based on thalweg lowering of as much as 4.6 ft in 10 of 13 cross sections <br />that were next surveyed during December, 1997. <br />Single-season pre-and-post mining surveys have never been provided, so it is impossible <br />to determine whether the operators have rotated mining activity throughout the pit as <br />promised, and whether this strategy has been effective for reducing erosion. Recent <br />thalweg incision suggests that most mining was conducted in the upstream part of the pit. <br />Gillam to Hellige, Nov. 28, 2003 page 5 <br />
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