BOARD01695

• Board Meeting Date: 7/25/2006
• Description: ISF Section - Injury with Mitigation Proposal - Case No. 5-04CW238 - Application of S.G. Company
• Board Meetings - Doc Type: Memo

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Blue River Datil Summary
The stream cross-section data was analyzed using the R2CROSS program. The R2CROSS output was
evaluated using the methods described in Nehring (1979) and Espcgrcn (1996). The CDOW selected six .
different sites for stream cross-section data collection. Three sites, X-Sections I, 2 and 3 were located
upstream of the High-Miller Diteh Diversion, X-S..-ctions 4 o.nd 5 were located downstream of the High-
Miller Diversion but upstream of the Oxbow Pond return flow point. X-St.'ction 6 was located downstream
of the Oxbow Pond return flow site (see attached map).

In summary, the CDOW reviewed stream cross-section data at 6 different locatiolls within the Blue River
instream flow reach. which is the subject of Case No.5-87CW298. The average width of the stream channel
within the mitigation reach is approximately 110 feet. The CDOW believes the six different data collection
sites represent the di ffcmnt and distinct typ..", of riffle environments found within this reach of the Blue
River,

The following tahle indicates the estimated hydraulic parameters expected at each ofthe data collection sit""
for a givcn flow amount:

Site AVED o/~WP AVED "IoWP
Q=125 Q=125 Q=85 Q.~1lI5
XS 1 .65 ........ 80 .56 76
XS2 .90 83 .76 80
n_. . -
XS 3 .62 79 .53 -- 75
XS 4UK .82 45 .70 .. 41
XS 5 uK.... .-. .'..
.81 57 .68 - 53
XS6 -.....-..,- .71 70 _68 51
,....- ...-
L ;\".~r.l'!ge .75 69 .65 63

AVED
Q=70
.50
.68
.48
.67
.61
.61
.59

%WP
Q-70
75
72
69
36
52
48
59

OR :-: Mods.lied now outside 0' R2CROSS mOdAl conndence Inr8rval (CRanae). TI1e COOW believes estlmared news tnat fall above or .
below the measured discharge and are outside of the accuracy range of the model may not give an accurate estimate of the necessary
nOWlo:: 10 prAS::Ql'VoA th. m:dur21 envlronmenl to .:I (e.::lI5:on.able degree.

At the six data collection sites the Blue River had a mean average dcpth ufO.75 feet at 125 cfs.. a mean
average depth of 0.65 feet at 85 cfs, and a mean average depth of 0.59 roet at 70 efs. The estimated aV'-'fage
depth at the two impacted sites is 0.67, at site 4, and 0.61, at site S, for a flow of70 cfs. As a result of the
stream channel modifications done in this reach both ofth"se sites maintain at least 0.60 feet of depth during
times of maximum impact. This additional depth will still allow for fish pussugc through the critical rifile
areas in lhC.lmpaetcd reach.

At the six data <;ollection site>; tho Blue River had a moan pen;cnt wetted pcnmeter of 69% at 125 cfs.. a
mean percent wetted perimeter of 63 % at 85 cfs and a mean percent wetted perimetcr of 59% at 70 cfs. Thc
estimated perGent welled perimeter at the two impacted sites is 36%, at site 4, and 52%.. at site 5, tOT a tlow
of 7U cfs. These lower values would be more of a concern if the channel average depth values mentioned
above were not maintain. In addition, the increased number of strcam habitat structures installed within this
reach provides additional holding habitat that was absent prior to the project.

CDOW Evaluation of Stream Habitat Improvements
The CDOW has evaluated the stream habitat improvement structw'es constructed by the Queen oflhc Riv"r
Fisheries Consultants and believes the struetures, along with the Oxbow Pond reach, significantly improves
the physical condition of stream channel and increases thc biological potential of this reach of the Blue
River. Tn 2005-2006, S.G. Company commenced restor.ation of the Blue River and Oxbow Ponds. The
restoration of the Oxbow Pond reach has increased the fishery habitat available to the Blue River by
providing an additional 2850 linear feet (approximately 200,000 square feet) ofhabiiat. In addition, the in-
channel habitat improvements have increased stream cl1mmcl water depth and winter holding capacity for _

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