EIS-0113_Section_11 - Hanford Site

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3.5.1.72
a) Can the data used in formulating this curve be documented?
b) Hysteresis appears not to be represented in this formulation
of the characteristic curve. What is the magnitude of
hysteresis in this sail, and what would be the probable
effect of incorporating hysteresis in the analysis of barrier
performance?
release water to evapotranspiration much more slowly. If the
clay layer is below the riprap zone, it will eventually become
saturated and transmit water under any sustained drainage from the
overlying layer
a) is the clay layer contemplated above or below the riprap
zone?
3.5.1.24
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W
W
3.5.1.70
3.5.1.64
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3.5.1.24
c) Nos selection of 4.5-metersas' the design thickness of the
u pper fine soil layer of the protective barrier based solely
on the computer simulation using this soil? 'What other
considerations, if any, contributed to selection of the
1.5-meter thickness?
M-13 Under the discussion of plant cover on page M.19, a cheat-grass
growing (transpiration) cycle of 152 days is reported to have been
used; however, the cited reference used 70 days; Why was the
transpiration cycle lengthened and what effect does this have on
simulation results for test cases 7 and 3 (Table M.7)?
M-14 Results of various simulations of moisture barrier performance are
given in Table M.7 and section M.5.2.1 (pages M.20-M.21). In only
ane (case 4) of the four test cases involving 1.5 meters of fine
soil were results reported for enough years to establish
equilibrium between yearly precipitation and drainage plus
evapotranspiration. Were simulations of lest cases 2, 3, and 6
carried to equilibrium; if so, what were the specific numerical
results?
M-15 On page M.21 (last paragraph) it is stated that although the
higher rainfall rates .(30.1 cm7yr) assumed for the wetter climate
scenario were normalized for the test years used in the
simulation, potential evapotranspiration was not. Does USDOE
assume in the simulations that potential evapotranspiration would
remain the same as at present, even though the climate became
wetter? If so, what is the specific rationale for this
assumption? If not, haw would an appropriate reduction in
Potential evapotranspiration affect results of test cases 2, 3,
Table M.7)?
- and 6 (
M- 1 6 Would the combined effects of increasing precipitation to 32 cm/yr
.(question 11.10), decreasing cheat-grass transpiration to 70 days
(question 11.13), and reducing potential evapotranspiration
appropriately for a wetter climate (question M.15) result in
significant drainage thr q uen the moisture barrier in test cases
2, 3, or 67
M-17 In the last paragraph onpage M.22, a clay layer system is
proposed to addition to the rock sublayer as a redundant
protective layer to minimize drainage under even extremely wet
conditions. The clay can be expected to absorb water readily
from the fine-soil layer if they are in contact, and it will
b) What documentation exists to show the clay layer could be
effective in reducing drainage ever the long torm?
M-I8 Atthe top of page M,24, the DEIS states, 'A proper cover design
is passible as f ng on-site materials...' Assuming a cover design
as outlined. in section M.2, have the specific on-site sources If
fine soil, gravel, and riprap been identified, quantified, and
tested for uniformity and quality? What specific information is
available to support the assertion of on-site availability?
M-19 Section M.5.4 discusses Cover Disturbance Considerations. As
addressed in question M.6 of this section, construction-induced
vibrations and earthquake shaking wou d . appear to bbe serious
eng ineering considerations far stability of the sail-riprap filter
zone.
a) What is the basis of USDOE's statement in paragraph two
regarding vibrations and earthquakes shaking that "mechanisms
like this ... seem highly unlikely'?
b) Has USWE conducted detailed characterization of occurrences
of natural layers of clean rock and gravel persistin g . below
fine soil layers Without disruption (page M.24)? If so, can
this he documented in relation to thicknesses, textures, and
'.densities of the proposed barrier layers?
M-20 Bander (1982), cited on page M.24 bf the DEIS, indicates wind
erosion from tailings piles in Colorado removed on the order of
one inch per year. Does specific evidence exist to support a
lesser rate of erosion for elevated, loose, upeagetated and
Unarmored fine-soils of the type proposed for the protective
barrier?
M-21 Surface armoring of gravel or rack is proposed on DEIS pages
M.24-M.25 to prevent sail 'erosion an the protective barrier
surface. Abundant evidence (e.g., Unger, 1971, cited in Appendix
M bibliography) indicates that a surface gravel layer (also known
as a 'stone mulch") substantially retards sail evaporation.
Assuming continuous plant cover cannot be assured, how can
effective erasion protection be achieved without degrading the
barrier's moisture retardation function?
M-22 Nowhere in DEIS section 5.4 on cover disturbance considerations is
biointrusion mentioned. As addressed in question 9 of this
3.5.1.21
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