HomeMy WebLinkAbout79 - 107 A (7)In addition to these: r,taJor reachos, t,hU ftsign 100 -year
W
rocurrence -interval l; .00df,Lows forproject tributaries
are as follows:
South Sycamore Creek; approve. 800 cfs*
46
North Sycamore Creek: 1,800 cps
Sheep 1-tollow 1,400 cfs
Mud Creek (above Sycamore Cr.) 51500 cf's
*by difference - no attenuation
These 100 -year recurrence-intervial floodflows were
developed by the Corps of Engineers in 1956 utilizing
the limited flood -data base that existed at the time.
Of particular interest is the 100 -year design discharge
developed for Big Chico Creek, as the precision to
which it was developed is pivotal to the capabilities
of the existing downstream channi-ils. Accordingly, this
0
would be of paramount importance to the feasibility of
this study (i.e., conveying additional floodwaters from
Rock Creek,)
Proceeding, with the advantage of retrospect and an
expanded data base, the flood hydrology of Big Chico
Creak may be updatedi The original design value of
lk, 000 cfs for a 100 -year peak discharge was developed
for the then -existing period -of -record from 1.931 to
1956. This 26 -year period had a maximum peak -of -record
of 8,260 cfs, which occurred in the 19,38 water year.
In the subsequent 22 years (or 23 years) through the
.1978 (or 1979) water year, 'two flood peaks exceeded the
previously -recorded maximum peak of 8,260 cfs. These
were the 1965 peak of 9,580 cfs and the 1970 peak of
9,270 cfs. These data combine to provide a 48= --year
(cr 49"year) data base from which a re-evaluation of the
pointfrequency peak -flood distribution of Big 'Chico Creek
-23--
may be made. This longer I)Oriod- of-recorca will also, lona
®
to a substantial iMpMveP1011t in Lha confidence lovel of
the re,suIts (by limiting the offocts of "last" degrees
of freedom) , Accordingly, the revised 100• -,year peak
discharge developed by the Log Pearson Typo III dist-
i-0
but:ion would be 12,540 cars utilizing a reclional coeffi-
cient-of�-skewness (see Appendix 7), or, about 9,500 cfs
utilizing a natural. coefficient--of-skewness.
Considering -the above analysis, the actual. 100 -year
recurrence -interval peak discharge .for Big Chico Creek
is more realistically about 12,600 cfs, rather than the
1.6,000 cfs value utilized in the original project design.
This would serve to suggest -that the downstream flood -
control facilities were commensurately overdesigned, based
on the 1.00 -year design criterion that was employed.
The effects of this original hydrologic overdesign on the
capacities of the downstream channels may be traced, by
reach-, as follows:
l) Big Chico Creek Below the diversion structure
is limited to a peak discharge of 1.,500 cfs
by a hydraulic inlet control, and would not be
affected substantially by the magnitude of
the upstream flood discharge.
21) Undo Channel (Sandy Culch) is . similarly
Limited by an inlet control, and would not
exceed the original design peak discharge
of 6,000 cfs.
3) The diversion channel to South Sycamore Creek
would be substantially affected by the upstream
peak discharge as it receives the excess
floodwaters remaining 'after Big Chico Creek
and tindo Channel are at capacity.,accordingly,
with an actual 100 -year peak discharge of
12, Goo cfs, the peak discharge in the diversion
channel would be _12,600 cfs less the amounts
discharged to lower Big Chico Creek and Lindo
Channel (assuming,no attenuation), or 12.,600'
cfs less 1,500 cfs, less 6,000 cfs,'for a maximum
-24-
peak discharge cif 5,100 cfs. This '-.11110ur1-ts to
an actual dischargo of 3,400 cfs less :than
the design discharge capacity of 8,500 ods
provided for this diversion channel,
4) The South Sycamore Creek channel, originally
designed for a capacity of 8,800 ofs, would
have an actual discharge of 5,400 cfs (assuming
minimal attenuation) which amounts to 3,400 cfs
of excess capacity.
5) Sycamore Creels above Sheep Hollow would convey
,the combined discharges of 5,400 cfs from
South Sycamore Creek and 1,800 cfs, per origi-
nal design, from North Sycamore Creek, ;Less
about 6% attenuation*, for a -total actual dis-
charge of about 6,800 cfs. This amounts to
about 3,200 cfs of excess -capacity remaining
in this reach.
6) Sycamore Creek above Mud Creek would then
convey the combined discharges of 1,400 ofs,
per original design, from.Sheep hollow and
6,800 cfs from Sycamore Creek above Sheep
Hollow, less about 4% attenuation, .for a total
actual discharge of about, 7,900 cfs. This
amounts to about 3,100 cfs of excess capacity.
7) Mud Creek below Sycamore Creek would receive
the combined discharges of 5,500 cfs, per
original design, from Mud Creek above Sycamore
Creek and 7,900 cfs from Sycamore Creek ^move
Mud Creek, less about 10t attenuation, a
total actual discharge of 12,200 cfs
indicates that there is about 2,800 c.: .%cess
capacity remaining in the original channel
design capacity of 15;000 cfs
The above actual -operating flood discharges for this flood
control project schematically in Figure 8, by reach, along
with the commensurate excess -channel capacities that remain.
*Note This attenuation was approximated from the original
design data for these reaches', which indicated that
an 8,800 cfs flow from South Sycamore Creek would
combine with an 1,800 cfs flow from North Sycamore
Creek, and result in a flow of 3.0,000 cfs in Sycamore
Creek above Sheep Hollow, or a peak attenuation of
about 6%.
25
'•.
E I;
ACTUAL OP`E RA FINE SEQUENCE
MUD
CREEKFLOOD-CONTROL FACILITIES
FIGURE 8'
N.T.S . GFS
SCHEMAT[C
GSC' 1
Oma
Q
CHICO
I' AIRPORT
S`fp
Npf1� CF..-cEK
0^0 L--_-_--__--
r3�J0� 0-
p cF
_
OUT,,R�EK
0
0
K
c, 6 800 CF
(3,pp01 a
400 CF-,gOp�
(3,40g�
3
�
Nl
G4�� 9 9
vi
N
t]D G GES. 'm
NOTES,-
0,x00 f
. 1. ACTUAL 100 -YR. DISCHARGES IN CFS
C.),
2. EXCESS CAPACITY REMAINING IN
o
CHANNEL. IN PARENTHESIS!
`�
-27-
Elements Q9 particular int:nrstr resulting frotri t 110
excess c1lanilal capacitios that r0amin, as related to the
feasibility or, conveying additional floodwateipst, from Rock
Crack, are focused on. -three reaches Of channel. TJIeso
are Mud Creak below Sycamore Creek, Sycamore Creek above
Mud Creek, and Mud Creek above Sycamore Creek. These
elements of interestare summarized below by reach:
Mud Creek Below Sycamore Creek
This reach will serve as the ult. male outfall for
any floo4waters diverted from, Rock Creek. Accord-
ingly, the excess capacity remaining in this reach
is of primary importance, The previous analysis
depictedthat the actual 100 -year peak discharge
expected is 12,201, cfs (as opposed to design
discharge of 15t000 cfs) and that an. excess capacity
of 2f800 c.Es remains in this reach. It was pro-
viously determined (see Figure 6) that the peak
discharge of the flood diversion from Rock Creek
would be 2,700 cfs, with accompanying total flood
volume of Ij070 acre feet. Purther considerations
developed in a later section of this report indicate
that the combined effects of attenuation and tribu-
tary drainage for a diversion channel from Rock Creek
would only ,slightly reduce the peal, discharge but
increase the total flood volume to 1,11.0 acre .feet.
Neglecting the attenuative effects of conveyance
(through the channel of Mud Creek above Sycamoi�e Creek)
it is apparent that the peak discharge of 2,700 cf8
is well within the excess caps, City Of 2,800 cfs that
remains in this ultimate outfall channel.
Sycamore Creek above Mud Creek
Although this reach will not di4ectly receive flood -
Waters originating from Rock Creek,, it will be subject
to backwater effects induced by stage increases down-
stream in 14ud Creek. The net effect of backwater
effects are readily discounted when the excess capacity
of 3,100 cfs remaining in -this rea.10h is folly considered.
This serves to demonstrate that, the channel of this
roach would be capable of conveying the combined peak
,flow of the reach plus that of the Rock Creek diversion.
Accordingly, backwater effects Would provide a sub-
stanti4lly-108ser problem that: would be localized to
the immediate area upstream of the confluence with
Mud Creek,. Purthor.moroj backwater effects would
-27-
rapidly 0-iminish (contn!rge Lo normal :Glow Conditions)
further upstream.
.; 1 ud Qrre'^ above Sycamore Creels
This reach will serve as the immediate outfall and
UQnvLY^ nq 011annel for diverted Rock Creek 4loodwate.rs ,
Accordingl.Y, it .'I s the reach of major cQn,oern, especi-
ally considering that it is or,7.,T tAftimally affected
by the hydrologic overdesign. inherent t•o the previous
reaches. The original design for this rea.;h envisioned
a 100= -gear peak discharge- of 5,500 cfs. Thi.: compares
favorably with results obtained via the peak=flood
model developed for this study (Appendix l) which
resulte,l in a 100 -year peak discharge of 5 t 400 cfs.
This indicates that, this channel is currently at full
capacity and could not receive additional floodwaters
I ithout conveyance improvements.
d ►
The combinecl peak flow from Mud Creek (5 , 500 cfs)
and from the mock creek hiversion (2,700 o:I:s) would
be about 8,000 cfs for a 100 -year event. This peak
was developed considering the effects of temporal
peak lagging (,translational) as well as minor
attenuation. Conveyance studies indicate that this
increased peak discharge will necessitate heighten-
ing the levees on this reach an average of about 1.75
feet downstream from the point of -the diversion out-
fall to the confluence with. Sycamore. Creek. In addi-
tion, back -levee heightening would ;,e required- upstream,
diminishing to zero from a 1;75 foot maximum height
at the point of the dive- i.on outfall. Substitution
of channel. widening (e.L -ealignment o£ one levee)
or other equivalent coma, ,ions of channel -conveyance
improvements, represents an alternate to levee construction.
Conveyance studies of the outfall for this reach
(i.e,., Mud Creek below sycamore Creek') indicate that
the at -age decrease realized from the 2,800 cfs excess
capacity, less the addition of diverted floodwaters
from Rock Creek, would be inconsequential (about 0,25
foot). Preliminary backwater studies (Bakhmeteff/Chow
Method) indicate that this stage decrease would only
extend about 1,500 feet upstream on Mud Creek above
Sycamore Creek (Pring to' convergence to normal depth
conditions). Accordingly, there would not be any
substantial improvement in the slope of the hydraulic
gradeline upstream, which limits options to improvement:`
of channel conveyance properties if additional flood:-
waters are to be accomodated.
28=
Based on this analysis, L -11P irlClQsion of addition4i,
4'100dWatOrS from Rock Creek by the Mud Crack Plood-con-ti.-ol
Facilities would be immediately feasible with respect to
the as -built capabilities of lower Mud Creek and Sycamore
Creek, The hydraulic -conveyance properties of upper Mud
Creek (above Sycamore Creek) would require improvement- if
the Rock Creek flood diversion was implemented. The
effects, and incremental effects, of the proposed flood-
water diversion on -these existing facilities are schemati-
cally depicted in. Figure 9.
Design Criteria
The 100 -year reourrence interval design criterion., with
a 1% -chance of being equ.aled-or-exceeded in any given
year, has been assumed appropriate for this study, as
per the original Corps of Engineers design. Generally,
this frequency is utilized for design purposes in agri-
cultural areas and other areas where -the expected loss -
Of -life or danger to the public health and sai:ety is not
a. factor. Accordingly, the Original design of the.levees
and channels utilized this frequency, with the incorporation
of 3 -feet of levee and channel, freeboard as a safety Zactor,
Many agencies, including the Corps of 2n9ineers, do not
consider the 100 -year recurrence interval to be adequate
for levee design in areas of residential development, and
recommend useage or the Standard Project Flood.
OPERATING SEQUENCE
WITH
ROCK CREEK DIVERSION
MUD
.CREEK FLOOD -CONTROL FACILITIES ,
Mui
FIGURE 9
N.T.S
SCHEMATIC
Doi
h r-�
7 t
p
t
o ► CHICO
clico N AIRPORT
K
i
NpR�G
L ------------
OC
8p
,
I+3x1(}01 p ,
Syc
MpgE
SYCA
�� Fps
cRF M0 G
}
sou CREAK
GF Ek (�t 800 CF
-200 Zi
5.0 CF
(4-40 S
ro _
3
�
S
C+
qtr,
9 o
.;
\ 1 R
G�
o
aN E
N'OTES="
aNsp00 cFS
1. ACTUAL 100 -,YR, DISCHARGE IN CFS
t 2. EXCESS CAPACITY REMAINING IN
o
0
CHANNEL IN PARENTHESIS. MINUS SIGN
4)
INDICATES EXISTING CHANNEL WILL BE
OVER CAPACITY
e,'.foots of those variables,
The lands adjacent to the t�xirttinq Mud Creek, flood -control
ch,annel,s, as well as those riparian to the proposed stock
Creek :Good -diversion channel, are undergoing or planned
for various levels of development. ror example, much of
the lands between Rock Creek and Mud Creek are currently being
considered in the contemporary planning process for development
to 1 -acre minimum suburban -residential land use. Should
such developmental patterns continue and/or be implemented,
a revisiva of the applicable design criteria (including
frequency of occurrence and factors -of -safety for freeboard,)
would be appropriate in order to isolate the degree(s) of
risk acceptable.
The level of risk associated with the 100 --year recurrence
interval has, and will continue to be assumed, appropriate
(as per the original Corps of Engineers design) for the
development of thia planning report, in lieu of more
definitive information;
-- Potential Location of Flood -Diversion Structure '£r Channel
The best location for the required flood -diversion structure
and attendant diversion Channel from Rock. Creek to Mud Creek
was developed, on a preliminary basis, considering numerous
physical (and economic) features. These features included
natural topography, hydraulic gradients, maximization of
flood protection afforded, land.use, parcel sizes, isolation,
apparent availability of rights-of-way, existing structures,
soils, existing natural channels, and limitation of cut and
fill requirements. To this end, several alternates wero
proposed and evaluated, resulting in the location and align-
G
Ina It ion - A profile of this preliminary alignment, along
with subdivision by reach, is shown on Plate 2 (in pocket)
Details of the nock Craek diversion structure, per the
preliminary location on Plate 1, are necessarily indeter-
minate at this conceptual-plahning stage. However, certain
apparent features at this time include the following
considerations:
1) The standard project flood should be used as
a. basis of design;
2) An engineered-earthfill embankment, approXimately
1,000 feet in length, would be required: This
structure may also require an interceptor channel,
upstream and -to the northeast, to provide channel-
ization for the naturally -braided stream channels
in this area;
3) The inlet control, for regulating downstream
discharges in Rock Creek, can probably be pro-
vided via multiple culverts;
4) The control structure for the diversion of flood-
waters to the south could possibly be developed
using -the natural outlet control of a protected
diversion channel (channel control), or�the
employment of an ogee or broad -crested weir
may be necessary.
Preliminary hydraulic channel sections were developed :dor
each reach of the proposed, divex8ion-ochannel alignment.
Standard channel -design criteria, applicable to all reaches,
included the use of a Manning's roughness coefficient of'
0.085, and the presumption of a trapezoidal cross-section
with l:3 side slopes. Freeboard or equivalent floodway
requirements, crown and maintenance -road widths, and land -
side slopes were left 'Indeterminate at this time,. of these,
the concept of a trapezoidal channel would probably be
subject to the most revision during preliminary & final
design phases, but was selected as an appropriate apbroxi-
0 -32-
mation :for the pirposes ot; this fetisibilit~y stuffy.
Information part-icLjjar to (-)ach ,roach (sea Lna"t'L 2) fellows:
Reach 1
Rock Creek to Keefer Road
Design Discharge = 2,700 C.fs
Depth = 6.0 foot
Channel Width 0 Base = 38.5 feet
Slope of Channel 0.00190
Length of Channel _ 1,940 feet;
'Transitions -
a) Convergence to 33 -foot base downst7.^eam
b) Drawdown :from steeper downstream grade
possibly
Reach 2:
Keefer Road to Hicks Lane
Design Dischargo = 2,700 cfs
Depth = 6.0 :feet
Channel Width @ base = 33.0 feed
Slope of Channel = b�00627
Length of Channel = 1,435 feet +
Transitions
a) Expansion to 36 -.foot base downstream
b) Backwater from flatter downstream
graCe possible
_ leach 3
Hicks Lane Downstream in Existing Channel
Design Discharge = 2,700 cfs
Depth = 6.0 feet
Channel Width @ Base = 36.0 feet
Slope of Channel - 0.00554
Length of Channel = 1,715 feet +
Tkansitions
a) Expansion'to 45 --foot base downstream:
b) Backwater from flatter downstream
grade possible
-,3 3
-, - Reach 4
Lower Reach, Modified Existing Channel
Design. Discharge = 2,720 cfs
Depth = 6.0 :Cent
Channel Width 0 Base = 45.0 feet
Slope of Channel = G.00375
Length of Channel - 980 feet +
Transitions - done
Reach 5;
In Excavation section
Design Discharge '= 2,730 cgs
Depth = 6.0 feet
Channel Width @ Base = 45.0 feet
Slope of Cannel = 0.00375
Length of Channel - 2,600 ;feet +
Transitions •- None
- - beach 6:
In Excavation Section upstream from Mud Creek. Outfall
Design nischarge = 2,730 cfs
Depth = 6.0 feet to 9.3 .feet ('variable)
Channel Width @ Base = 45.0 feet
Slope of Channel = 0.00375
Length of Channel. = 1,600 feet
Transitions
a) In backwater ,from Mud Creek
Potential Transient Effects of Diversion,
if the proposed diversion of floodwaters from Rock Creek
to Mud Creek is implemented, several operational transient
effects; are anticipated. These should not be considered
insurmountable, or even atypical,, but constitute some of
the effects unique to 'this project. Accordingly, they would
need to be considered in detail, along with any other
similar effects whish may arise, in the preliminary and
final design phases, As such, discuss�'lon of these effects
-34-
T . _.
is s0l"Qwha h premature at t_W.8 early -planning s tagO but is
presented to insure disclosure, The basic elements of
these operational effects are
l) The proposed diversion will cause transient
backwater effects on upper Mud Creek and on
lower Sycamore Creek. This will require
levee improvements on upper Mud Creek (above
the diversion outfall) however Sycamore Creek
as -]wilt facilities are currently below design
capacity and will not: require modification;
2) The downstream reach of Mud Creek, westerly
of State Highway'32j was originally designed
for a frequency of protection o.0 only 2% (50 -
year recurrence interval) under certain con-
ditions* The potential effect of routing
additional floodwaters through this reach is
currently obscure (particularly considering
the original hydrologic overdesign and the
substantial attenuation expected of the com-
bined flood crest) but should be evaluated,
along with the original rationale :for the 2% -
design frequency, before proceeding with design
studies;
3) The existing operations of the Mud Creek flood -
Control facilities have been suspected of caus-
ing backwater -flooding problems in the Xusal
slough area, where it parallels the Sacramento
River. The effect of backwater resulting from
conveying additional floodwaters in Mud Creek,
as well as the elfec''s of the amelioration of
the magnitude and fregoency of floods in Rock
Creek (a portion of which is currently re-routed
to the upstream reaches 'of Icusal Slough), should
be considered;
4) The unprotected lower reaches of Sig Chico Creek:
and Lind:o Channel have been experiencing pro-
blems from backwater flooding above their con-
fluence with Mud Creek. This problem is currently
being studied, on a preliminary basis, by the
Corps of Engineers. The effect of additional
floodwaters in Mud Creek would need to be con-
sidered for this area;
5) increased and/or induced flood heights in the
Mud Creak, and lower Sycamore creek will affect
tho gxadient.s, "available for urban-storn, dr,1111-
ago outfalls. %',ho temporal. pattarns of fIood-
ing should, minimize these problems, but could
be of consequence in low gradient areas.
Adclitionally, the areas to tba east of the pro-
posod diversion channel alignment may need
alternate drainage. outfalls;
6) Shallow ground -water, seepage from the proposed
diversion channel could adversely affect the
use of adjacent agricultural. lands for some
purposes.
Major Improvements
Major improvements and acquisitions required for implement-
ation of the proposed flood diversion, include the following:
J.) Diversion Structure on Rock Creek -
This would include the embankment,, spur embank-
ments and control, sections, interceptor channels
and channel re -alignment, flood pool excavation.,
downstream erosion -control improvements, emet-
genoy-overflow spillway or bypass channel and
attendant maintenance roads and security fencing.
2) Diversion channel from Rock Creek to Mud Creek -
The diversion channel would utilize approximately
4,200 feet of existing channel. that would require
modification -to improve hydraulic capacities,
get the requirements of a previous section*
Another 6,000 feet of channel would need to be
excavated to depths of up to about lQk feet,
averaging about 6k feet. LevOe maintenance
roads; access and security fencing would also
be required. Two existing box culverts would
requite replacement, in all probability, by
bridges.
3) Upper Mud Creek
The conveyance of the upper Mud Creek channel
will require improvement to accommodate the
flood waters diverted from nock Creek. This
:Would include either raising levees about 1.75
4:,rsm4l, uii'Agri i nel 1-hn_ entistinO channel,, or a combi,
excavation- MICY levees will bo required up-
stream fronj tho diversion outfall..
4) Rocl* Creek
some channel alignment and conveyance improve-
ments may be necessary both upstream and. down-
'
stream of the proposed diversion stricture.
5) night-of"Way
Land will need to be acquired for the the
diversion structure, the diversion channel., and
for the levee improvements or channel ;widening
on upper Mud Creek. Additional sands or ease-
ments will be required for intermediate mainte-
nance-access roads, access -to severed lands, and
for any improved channel areas contiguous to
'the diversion structo e on Rock Creek.
Additional right"oat'-way may ha required if;
during the course of this project, Hicks Lane
were to be realigned to the east of the proposed
diversion channel. This action would improve
the poor, existing alignment of flicks Lane while
the costs would be offset by savings realized
in eliminating one bridge along the route of
the diversion channel. (at the existing flicks Lane) .
Detailed costs estimates for the development of this pro -
Posed flood--di*,ersion project are not a pari: of this physi-
cal -feasibility study, however a budgetary estimate was
developed for initial consideration and to serve as a guide
for future project planning. Actual costs will depend in
large, upon the particular options selected, however the
magnitude of costs should be in the $1,500,000 to $1,900,000
range. This would include the cost of land acquisition`
construction, engineering, legal. and miscellaneous expenses
as of early -1979.
-37-
M
2.1
ALTBRNATIVES
Several alternatives to tho proposed flood diversion,
as presented, May be worthy Of consideration. These
include upstream storage, channel imprOVeMntt ground-
water recharge, flood meadows, and no project combined with
f'loodl-plain zoning.
- Upstream Storage
A preliminary topograph.ic reconnaissance of the lower
Rock Creek basin indicates that several, good sites for
the construction of a small f-lood-control dam may be
available.
'lable
Several potential sites on Rock Creek above Anderson
Fork (about 4-5 miles opstream from the currently 'proposed
diversion) appear to be topographically and geomorphically
suited. These sitas may have the potential of storing
approximately 4,000 acre feet, which is almost four -fold
the 1,070 acre feet of storage requiredi These sites are
also isolated and uninhabited, but do serve to Support
habitat for a sport fishery. Another site of limited
potential, exists:On Anderson Fork (about 5 miles upstreaii
from the proposed diversion). This site is also uninhabited,
but does not appear to maintain a pa ' rticularly-valuable
fishery habitat. The impoundment storage of this site
appears to be limited to about 1,400 acre feet. it would
also require careful hydrologic 'study to fully assessthe
I
impact it would have on flood magnitudes on lower Rock
Creek. This is due to the relatively small size Of the,
Anderson Fork basin,as compared to the total area of the
Rock Creek basin.
A M4-vjO--,' Irawback to the of any of -these sites appears
to center about foundation adequacy. These sites are all
M
Z]
0
E
located on the Tuscan formatiol-1. Which is generally comprised
Of ineOVVOningj near. -horJzon,L,,1l layers of mudflow breccias,
andositos and intervolcanio residual soils. This Tuscan
bedrock is frequently fractured by faults or joint systems
in the general area of study. More importantly, occasional
layers of increased permeability are often interbedded
Within the matrix of the Tuscan formation. Such permeable
zones can be difficult to locate and may require extensive
grouting during foundation preparation.
While the limitations on foundation adequacy may be of
some concern, they would be of least concern for a flood -
control dam8ito due to the limited periods of impoundment
expected. This is in contrast to a water -supply damsite
than would. be expected to have perennial aznpoundments, 11-hus
subjecting the foundation materials -to continual, saturation.
Major advantages in utilizing a flood -control dam would be
QD
the relative isolation of the structure and the additional
downstream lands protected, by virtue of its upstream 100a -
tion.
Channel Improvement
The use of levees and conveyance improvements to curtail
overbank flooding would not appear feasible for Rock Creek.,
This is due to the long distance
these types of improve-
ments would need to traverse in order to prevent flood.ing'
of downstream lands. Accordingly, such improvements would
need to extend to the mouth of Rock Creek, a total distance
of at least seven milestven though much of the adjacent
lands are agricultural, allowing the use of higher design
frequencies, it is doubtful that the benefits received
would Justify the costs.
0
A rather 'unique solution to the flood . control problem
may beavailable. This would be in the form of a aomb.t-
nation flood -water disposal and qrQund-wator recharge ,prop-
ro-
ject at the site of the abandoned sand and gravel pit
jec
between Garner and Nicks Lanes (see Plate 1). The diversion -
channel, alignmentf as proposed, could be re -rout od to
this pit, serving to decrease the channel length as well
as eliminate most of the required channel excavation (see
Plato 2).
The current volume of this pit is estimated to be approxi-
mately 750 acre feet. This amounts to about 68 percent of
the 1,110 acre feet volume of the flood -diversion hydro-
grap I h, including tributary drainage. Assuming that up to
four feet of infiltration could occur during the eight-
hour duration of the flood -diversion hydrograph, there
wnuI6 be a volume deficit of about 160 acre feet remaining.
This amounts to only about 14 percent of the total required
volume. Accordingly, it may be feasible to acquire adjacent
lands for excavation, or to deepen the pit within the
current limits, to provide the additional volume required.
This excavation process could be geared -,.)ward the pro-
dqction of sand and gravel, a marketable commodity, to
offset the development costs.
Since the floodwaters of Rock Creek are substantially non-
urban in character, the water quality should be acceptable
for grouftd-watet recharge. Sediment, and other Boil -clogging
agents, should be substantially less than that existing in
the natural floodwaters of Rock Creek. 'phis would be due
to skimming action of the diversion weir, which Would
minimize the introduction of the stream-s6diment traction
load to the diversion channel. Excessive rates of ground-
water recharget and the attendant rise in ground-
-40-
water levels, could be a Potential (but inZrequent) problem.
Those factors,, and others, would need 'to be l:horoughly
evaluated.
Flood Meadows
This concept of floodwater management: involves the use of
shallow, widespread ponds or "flood. meadows" to provide
retention storage for attenuation of the flood crest. The
diverted floodwaters eventually return to the source stream,
loss some infiltration and evaporation, but after the normal
flood crest has passed and the stream is at a Lower stage.
In this sense, "flood meadows:" are similar i- operation to
conventional flood -control res--,-Yoi.rs, except, that. the depth
of storage is much less.
since the depth of storage is shallower, commensurately
larger areas of land are required. Thus, a necessary
prerequisite for application of the f=lood -meadow concept
is a large expanse of relatively -flat, inexpensive land
in close proximity to the stream. Relatively flat land is
required to avoid the construction of numerous smail levees
(or contour cheeks) in order to maintainshallow storage depths.
The large areas of land also serve as sedimentation basins
that can improve the agricultural capabilities of the
soil substrate. This, along with added moisture afforded
the soils, frequently serves as a land -reclamation project
for soils of limited productivity. The subsequent late -
season vegetative growths are similar to those of natural
s tream meadows,;and can provide valuable grazing lands as
as a by-product.
A review of the Rock Cree}N basin topography shows there is
lack of grade with which ick convey diverted floodwaters.
This lack of grade. subse5JUQntly limits the useable land
area to about; 300 acres, which would not appear to be
sufficient for the flood volumes expected,
A manor ridge serves es to isolate hack Creek from most of
this available land that would; appear to be acceptable
for use as flood meadows. A near breach in this .ridge
exists about Vi miles upstream from the ourrently-proposed
diversion location. if this saddleback ridge could be
excavated to the elevation of Rock Creek: approximately
1,200 acres of land could potnnt,ially be developed to
flood meadows and other off -stream storage fac,*.iities.
The res.ia1'1- .ng storage depths for a divers ot, of 1,070
acre feet would be approximately 1 -foot average, or per-
haps depths of 2 to 3 feet net, after contour check
construction and elimination of unsuitable areas. This
depth range would be the correct order -of -magnitude for
a "flood meadow".
Since this location, if excavated and developed, would
�
appear to allow the use of "f lood meadows" as well as to
provide Protection for a larger area (since the diversion
would be .Located further upstream), a brief feasibility
study was conducted. The excavation required at the
saddleback ridge would be nn the order of 65,000 cubic
yards. This would be classed as moderately -difficult
e xcavation and would extend a distance of about 3,500 feet.
The cost of this, along with the required diversion structure,
right-of-way, land preparation and ;flood easaments (if
legally feasible) for the"flood meadows" suggest ggest that
it could be competitive with the Proposed pro" However,
sodio-political factors would be expected to increase,
and engineering would be state-of-the-art since the
"flood meadow" concept is usually applied at a smaller
scale.
-429-
,- Flood 'lain Zoning and :1,nsuranco
This is a non-structural, alternative that combines flood-
plain delineation and floQd-plai«, zoning with Federally -
subsidized flood insurance. The objective of this type
program is to regulate development within identified flood
plains by appropriate zoning and land use. Existing, non-
conforming land uses would be allowed to remain and would
be provided the opportunity to purchase flood insurance
at subsidized premium rates. These non -conforming land
uses are then eliminated via the various processes of
attrition, such as fire, flood or retirement after economic -
life service. Expansion of these non -conforming uses is
forbidden.
Flood insurance has generally been unavailable from the
private sector due to the high premium cost. The economic
Justification for the extensive federal premium subsidies
required; is to reduce the need for and dependence on public
flood -disaster appropriations. The program is administered
by the Federal Insurance PxIministzaLlons Department pf Housing
and Urban Development, as authorized by the National Flood
Insurance Program of 1968 and the Flood Disaster Protection
Act of 1913.
This program is usually administered on a community -wide
basis, meaning that all the Lands of the local political
jurisdiction of an eligible community must be included.
This would r° t� that all the unincorporated area of Butte
County be to the program.
The.histori. of a community relying on Federal
flood -disaster aipk,opriations (sans structural flood improve-
ments or participation in the flood --insurance program) has
been effectively,precluded via the provisions of the
Disaster Relief Act of 1974. This Act reinforces the
-43-
l• UNDXNG SOURCES
whereas the proposed diversion project, or one "of the
alternatives, appears to be physically feasible; the out-
look for locating suitable funding sources within a reason. --
able time frame is less than optimistic. This poor outlook
is a joint product of the general austerity policy in govern-
ment, backlogs of approved projects, and the incapability
of the proposed project to satisfy all aspects of funding
agency criteria. Possible exceptions to this outlook may
exist with the Corps of Engineers, for the proposed project;
or with the Department- of lious'ing and Urban Development, if
the flood -insurance program alternative was to be selected.
A summary of applicable funding sources for the project, as
currently proposed follows:
County/Local funding
Capital amortization for the proposed project would be on
the order of $150,000 annually. This annual amoun', exclu-
sive of operating costs, would probably stress the -
revenue -generating abilities of the area of benefit (exclusive of
agricultural lands) The relatively low tax base of the
benefiting area would necessarily result in high, assessment
ratios, and consequently, high assessments.
The formation of a local assessment district would be
further complicated by the restrictions imposed by Proposition
13 and the subsequent dissolution of the County Public -works
t?nt�nl tri nn rllin A i n flim nf4-ai 4-h Xlefnn°rrii nfrl -,r f hr3 i9aea of
El
Corps of Bnginoers, U.S. Army
The Corps of I:,nqineers would be the logical entity for,
developing the proposed PrOJOct, since they devoloped the
Chico -Mud Cree% facilities. They Would also ultimately
need to approve (via the State Reclamation Board) the pro-
posed project details, Additionally, this project may
qualify for funding under the provisions of the Flood
Control Act of 1936 (subject to Congressional approval),
however a long implementation time may be expect�.d-
if funding via the Flood control, Act is sought, the
Board of Supervisors would need to provide 1st District
Congressman, Harold T. "Bizz" Johnson, with a resolution
requesting the introduction of a resolution *to the House
of 'Representatives authorizing -the Corps of Engineers to
study flood -protection measures on Rock Creek: Since prow-
jects under this Act are generally limited to the peak -flow
criterion of 800 cf$ for a 10 -year recurrence interval
flood, the resol,ution(s) should include the 10-t 50 -
and loo -year peak -flood discharges for Rock Creek.
Agricultural Stabilization and Conservation Service
Historically this agency has administered small ' flood -control
projects, primarily in agricultural areas. Howevert congres-
sional and executiveactions have effectively circumventea.
much of the flood -control funding for the programs I of -this
agency. Little improvement in.this ,outlook is expected
in the near ftiture, as most programs are currently centered
about range improvement and irrigation efficiency.
Soil conservation Service
The Soil consprvation Service (SGS) 18 involved in small
flood-dontrol projects through Public Law 8i3-566 of 1954.
Under the provisions of this law, such, project I s are under-
-46-
taken cooper, atjvejy with local sponsors i:rx the form of
resource conservation district, and are financed partly by'
local funds. Also, projects are generally Jimit:ed to
drainage areas of 400 square miles or less, and are subjoct,
t -o cost -benefit; analysis and Congressional approval.
The prospect: of obt.a3,ning cooperative funding under this
Act is immediately complicated by the lack of a resource
conservation district for this area. Such x district is
a necessary condition -to obtain :funding under this program.
A resource conservation distract could be formed, pursuant
to the provisions of the California Public Resources Code
of 1970, but the requirements of C.E.Q.A. (environment tl
Impact) and L.A.F.C.04 serve to indicate this would be a
time-consuming process.
f
47w
- -
I
RECOMMENDATIONS AND CONCLUSIONS
1) The limiting channel czIpacity of Rock Creek, in tile, area
of study is approximately 3j200 cfs. This channel
capacity is equivalent in magnitude to a peak -flood
discharge with a recurrence interval of Oig'At years,
6be elXpOcted to
(The, existing channel capacity WOUIr
be equaled -or- exceeded once every eight years, On th"'�
average). Considering that the lCo-yer
,Ir y*oourrence-
interval peak dischetge is estimated to be 5,500 Of's,
may be conrtluded that a poLentially-zha. ardous flood
lev jf�l Oxist.
d diversion of excess Rook Creek floodwaters
the improved facilities of Mud Creek is reasonably
feasible, from a physical and engineering standpoint.
The cost/benefit and economic feasibility is subject
to question.
3) The project, as proposedi and applicable alternatives
should be carefully reviewed for economic and political
feasibility.
4) The feasibility of applicable alternatives; 'which
include upstream storage, gtound-water recharge, flood
moadoWsi and flood -plain zoning -ombined with the flood
-
insurance program; should be considered and evaluated.
The flood insurance alternative appears to have parti-
cular economic and physical merit, and warrants care-
ful consideration.
5) This report should be submitted to into -rested agencies
and organizations for comment. These should include
the corps of Engineers,, State Reclamation 13oard,
Department of Fish and Game, Butte county planning
48'-
CA
0
11
U
M
Departmont, and the socramento Valley r,4andowners
Association, among OtbOrs-
6) if, the project recoives favorable review, as proposedr
and a funding source is developed, Phase TI of -the
feasibility study (preliminary design) should !-.Ie
initiated. This phase should include such features
as a determination of the area of 'benefit; cost -benefit
analysis! photogrammetric surveys; test borings; route
and site surveys; preliminary design of hydraulio
structures and channels; right-of-way requirements;
construction quantity take -offs; cost estimates for
construction, operations and maintenance; and develop-
ment of funding sources as well as payback and assess
mens procedures.
Additionally, any further studies should include the
institution Of a streamflow data collection program.
This program should; as a minimum, provide peak flow
and hydrographic information for Rook Creek below
Anderson ForXf and Mud C.eek at Hicks Lane, combined
wi-i--h the determination of annual peak flows on Xeefer
Barnes, Il.11. , Jr. 1967; Roughness Characteristics of
Natural Channels; U.S. Geological Survey Water -Supply
Paper 1819, 213p
Chow Ven T., 1959 open -Channel Hydraulic$; McGraw-
Hill, New York, 680p.
Corns of Engineers, Sacramento District; :1.963; As --Built
Plans for Chico and Mud Creeks and sandy Gulch Channel
Improvement, Levee & State Highway embankment Construction;
U.S Army, 54 sheets.
Corps of engineers, Sacramento District:; 1957: Ilydro,logy -
Design Memorandum No. 1 Sacramento River and Major and
Minor Tributaries, California; U.S. Army, 31p.
Corps of Engineers, ,Sacramento District; 1957 General
Design. Memorandum No. 2 - Little Chico and Butte Creeks;
U.S. Army, plus addenda.
Corps or engineers, Sacramento District; 1961; Design
Memorandum No. 5 - Chico and Mud Creeks and Sandy Gulch
General Design; U.S. Army, 37p.
Corps of engineers, Sacramento District;
Operation and Maintenance Manual, for Chico and Mud Creelts
and Sandy Gulch; U.S. Army, 3,8p. + Exhibits-.
Corps of engineers, Sacramento Distract; 1975:
Unpublished Preliminary Data --- mock Creek and pane Creek
Plood Hazard; U6S. Army, miscellaneous unbound pages.
Dalrymple, T. and Benson, M.A.; 1967: Measurement
of Peak Discharge by the Slope -Area Method; U.S. Geolog-
ical Survey, Techniques of Water -Resources Investigations,
Book 3 - Chapter A2', 12p.
Dalrymple, T. and Benson, M.A.; 1967: General Field
vies for Indxect Discharge e measurements?
and Office- Procedures :�
U'.S. Geological Survey, Techniques of Water -Resources<
Investigations, Book 3, Chapter Al, 30p.
��nabook of Hydraulics ;
Ringo . PHand
r13
I
wl
McGra-llill, New York, 13sections.
Moore, Donald 0. , 1964: TechnigIues for Synthesizing
liydrographs; U.5. Geological Survey, 92p.
50--
IM
Pot�cr, P—G- t eG al., 1967: Saaramento Valloy Fast Sicle
Investigation California: Department of Wattor Resources,
Bulletin No. 137, 299p.
U -S. Geological Survey, 1961-76; Water Resources Data
for California, U -S. Geological Survey Annual Open -File
Reports.
U.S Geological Sjxrvey, to 1960: Compilation of Recor s
of Surface Waters of the United States, .Part I!; U.S
Geological Survey Water -Supply Paper 1735; 715p.
U.S. Nuclear Regulatory Commission, 1976: Design Basis
floods for Nuclear Power Plants; USNRC Office of Standards
Development Regulatory Guide No. 1.15, 79p.
U.S. Water Resources Council; 1977 Guidelines for Deter-
mining Flood Flow Frequency; Bulletin too. 17A, USWRC
Hydrology Commit -Lee, 8 section t tables
Waananen Arvi, 0. , 1973: Floods from Small Drainage Areas
in California -- A Compilation of Peak Data 1958-73
U.S. Geological. Survey Open -Filo Report, 26op.
Waananen, A.O. and Crippen, J.R., .1977 Magnitude and
Frequency of Floods in California; U.S. Geological Survey,
Water -Resources Investigation 77-21, 96p.
Young, L.F. and CruffR.W., 1967: Magnitude and Frequency
of Floods in the United States, art 11, Pacific Slope
Basins in California, Volume 2, Klamath and Smith River
Basins and Central. -Valley Drainage from the Fast; U.S;
Geological Survey Water -Supply Paper 1686, 3089..
t N M. ANOCRSON
P+ OWIMNO UIM4 CNETINCQR
4N.UYC,' 7Ei.1;1�I1fjNl;,' Pbflfil �rlClr'/,"aSld
10 0# VA,41(ORNIA 195976
1 5;S �, t k+ i �:4aJ � �. to t`.t Baa 1 +.. r } J J, att �, •4� J'9r�R �i�..
� �, ..�, 7 _ �C. ,r• ,3.�rR �. .. �.t Y i__.. .a �� :.�_. +.,_• � __. �.. .J ..��? <.. ... ..a c-�.._�.r�, L:, c;_ .':1.',...�-��
. ate..
k
�J
p Ct
UGkI MYRT41r AV
�H
AE
REGIONAL FLOC
JC0r ap
Ro
Butte c4;
t N M. ANOCRSON
P+ OWIMNO UIM4 CNETINCQR
4N.UYC,' 7Ei.1;1�I1fjNl;,' Pbflfil �rlClr'/,"aSld
10 0# VA,41(ORNIA 195976
1 5;S �, t k+ i �:4aJ � �. to t`.t Baa 1 +.. r } J J, att �, •4� J'9r�R �i�..
� �, ..�, 7 _ �C. ,r• ,3.�rR �. .. �.t Y i__.. .a �� :.�_. +.,_• � __. �.. .J ..��? <.. ... ..a c-�.._�.r�, L:, c;_ .':1.',...�-��
. ate..
k
Regional Model Devolopmont -
On the prooijmption thnt this ;,rec, O:r. 13utto County may warrnnt
Z"'EllYsir, On ;the Of a separate Jjy�.jroloqjc region for
1.) a r -I I C - f 10 o d c h a r a c t. o, r it; 1-. J c ,i, -111 O-Ra"nill0tiOn OF; exinting
.�;trOaMfloiv datn in 'the immocliato area wcip:, initiated. pril"11,-Iry
criteria for the melccti011 Of potenti-Etlly-correlable -streams
included:
PX-OxiMitY to the Rock Creek drainage basin
This was tentatively outlined, as being within a radiu6
Of approximately 27 miles fXOM the centroid or the
Rock Crook Basin. -
2.)
Similarity Of geologic framework -
The Primary criterion for selection in this regard
was location on Cascadian extrusivo volcianics
(more Particularly, the Tuscan. fOrmation).
3v)
br-linage area classification as a small stream
This was subjectively determined to be within a
range of aPPrOximat0lY 0.10 'to 250 square miles,
with particular emphasis on areas of similar size
to ROCk Creek (20 to 50 square miles),
4.)
Similarity of flood regime
This Criterion requires that the primary cause of
Flooding on -the stream should be induced by frontal
rainstorms, instead of- thunderstorms or more
particularly, snOWM01tv This can be doterMined
by examination of hirtorical records to determine
the season Of flooding. An additional guideline
is that significant snowmelt flooding in this
.
area generally will not occur at e levations less
than about 5,000 feet.
5-)
Natural flow regime
This requirement excludes streams with m1ajor
storage reservoirs and/or diversions upstream
from the gaging site.
6.)
Length of Record
Since the primary objective Of the 'developed model
would be for prediction Of flood peaks with
recurrence interval of up to 100 years i the
.minimum
length of record should exceed, or be
correlable to a10 -year period.
On application of these critorila to existing strea_mflo4ql data
stations,
it was readily appprent that only a, few' streams
Would qualify in all re,spectr,. According] some streamflow'
I
data that obvi.ola.aly did riot. �l"al�.r.Y in some tispoots or thn
criteria, were included in tht. ini.ti al data bale, with the
gvialificration that; they could be el.imin.aLed after additional
tonal
analysi.s, if nocessary. `I,'he streams selected for this ini-
tial data base are listed ;in Table A.
The data base of Table,A was compiled from the records of
the U.S., Geological ,survey, with the exception of data for
Little; Chico Greek near Chico, which was obtainedfrom the
records of the California Depart ,ent of Water Resources.
All data were updated in -so --far as :possible.., to include
preliminary, ;unpublished data for the 3.977 and 1978 water
years. Correlations between similar stations were performed
in an attempt to loccte potentially spurious data(f'or later
consideration). This process was particularly necessary
for some of the crest -gage stations, where hydraulic ratings
tend to be poor. Some estimates of instantaneous -peak
discharges were required for Little Chico Creek near Chico,
since existing records are determined separately for the
creek and for the flood. diversion ( the timing of ;the individ-
ual peak discharges seldom coincide). Some of the data from
short -record stations were extended, for a maximum of tour
ears if a
years, good correlation with a nearby station existed.
in addition, the initial data base includes two stations
that do not conform to the initial proximity limits estab-
lished. These were included to improve the limited irforma-
tion available for very -small streams (Shingle Creek near,
Shingletown and Wyman Ravine Tributary, .located to the
north and to the south of the proximity radius, respectively),
Examination of this initial data base of potentially
correlable streams shows that it consists of 18 streams
(stations) ranging in drainage area from 0.62 to 208
square miles. The number of station ears of data tot
� y als,
410 years, or 423 yoa,ts of extended station years. Unit
_2-- I
m
C
Tablo. A -- Sunimary of Potontiaj,ly Correlative Streams
MaximtIIII
Drainage
Y04rs
Pon% of
USGS No.Stream
,
�111M-� ------(si)
Area
_
Record
Of
R-Ocord
(Of-s/mj2)
11-3900,.45
Little Chico Cr. Trib.
0.62
ll
(14)
145.2
11-4033.40
Granite Cr. C-1) Tobin
0.79
11
200.0
11-3829.50
No. cork Calf Creek
1.26
5
(12)
27.0
11-3902-00
Gold Run Tributary
1,31
13
193.1
11-4074,,00
Wyman Ravine Trib.
1.72
13
151.2
11-3762.00
Summit Cr. nr. mineral
1.80
13
122.2
11-3740,60
Shingle Cr. nr. ShingletoWn
3.25
13
187
11-3896.50
Scotts John Creek
3.76
9
(12)
54.8
11-4040.00
Grizzly Cr. nr. Storrie
5.20
14
30119
---DW.R---
Little Chico Cr. @ Chico
25.4
15
155.4
11-3897.00
Butte Cr. Q Butte MPadows
44.4
14
96.6
11-3825.50
Doer Cr. Below Slate Cr.
69.4
9
(13)
113.8
11-3840400
Big Chico Cr, nr. Chico
72.4
48
132.3
11-4053.00
West Branch Feather R.
110
21
239.1
11-8790-00
Antelope Cr. nr Red 81f.
123
37
139.8
11-3315400
Mill Ct. nr Los Mol'nos
131.
50
277.9
11-3900400
Butte Cr. nr. Chico
147
48
144.2
11-3835-00
Deer Creek nr. Vina
208
62,
114.4
Extended Period
-3-
rr,%nge from 27.0 to Sol .0
cubic-2oot per of ,.cond per squire milo (c:ctm).
roint Vrequency Analyois -
Loq Pearnon Type III distributions ware devolopod. for the
-IM!Uial pealk-flow data ieries of each t in Table A,?
, , ji r, a tio n
pQr8uant to the PrOcedUres recommended by Bullotip 171 of
the U48. Water Ro5ources Council. This process generated
Skew coe:Mcion 't'--- (natur-,11 skews) for each station, which
were retained for further analysisi
Since the procedures recommended by the u. Water Ae8ources
Council indicate that regionalized skaw,+ or a Particular
region are preferable, to individual natural sltew,,3, an investi-
gat-ton was Conducted -to determine if the use of a regionalized
31
"I'010 value would be aPPrOprinta- ',> IU. proce3,r. ilicludod
development of geographical plots of natural ,3tjtior) -,kews
(Plotted at, the centroids of the respective basins) -to
investigate areal skew variation; correlation analy.,A,. of
natural skei,,Tj as a function of basin drainage area, mean
basin elevation and percentage of basin area above 5,000
feet elevation; and a graphical analysis of natural station
skews as a function of the period of record of the station.
The geographical plots generally depicted an east -west variation
in naturc-.,l from positive in the east to negative in.
the west. A correlation of mean basin elevation and percentage
of basin area above 5,000 feet vs.: natural Station Sjcet.j revealed
a general trend toward positive skewness with increasing
eleva-bion(s)., However, the results of this correlation also
coincided with the geographical plots (in that elevation
generally increases to the east). Accordingly, the physical
-significance of the results from thi.s rolatiol-i8hip are some --
what obscure due to a possible cross -correlation of the variables.
A correlation of drainage area vs. natural station; Skew generally
indicated a convorgence of- 55E w at the _0.5 to -1.0 t~'kwq
intoa,v tl with inca.oa.sing drair,ago area. However, it Waa
iw misod that thin was aDJO alba oct to bias, hs the: prob-
ability of the drainage; basins having „omo portion
of the basin Above s,000 .(,eat elevation could,, not readily
be accounted for. Also, the influence of the larger drain-
age basins having the longer period($) of r000rd needed to be
considered to eliminate the possibility of parameter cross
correlation,o
subscribing to the premise that a regional skew does exist for
the area., and that -rhe best or most probable achievement of
'this regional skew would be indicated by the natural station
skews of the long-term gaging stations, a graphical analysis
of -the variation in natural station ,ikewness with period
of station record was employed. mile initial relationship
indicated that the natural skewness values for -the stations
in Table A tended to converge at a value of about -1.0, This
relationship was somewhat obscured., as several interpretations
could be developed from the ,same graph. To partially
ameliorate this problem, each station in ".able A was .sub•-
jectively weighted (on a scale of poor., fair, good or excel-
lent) based on its similarity with hack. Creek and the
reliability of the gaging data. These weightings were ass ghed
-to each station considering drainage area, geology, cli.matol..
og,y, proximity, flood regime, storage & diversion,%, type of
gage and gage rating, period of ;record and reference to;
the east -west geographcial trend, previously discussed. The
natural skewness data were then re -plotted, with the letter
corresponding to the suhjecti.ve weighting superimposed on the
point in the coordinate field. This graph is shown in Vigure A.
With the weighted graph of rigure n greatly facilitating
the analysis, the following interpretations were possible:
-5—
COEFFICIENT
OF
SKEWNESS
+
vs.
PERIOD
OF RECORD
1.. ) The 000fficient of skecnerss Probably convergos to a value
of -1.0 as the period of rrcord approachos 00 or 1.00 years.
2.) The coafkicion't, of, ske�tina ss CoUld.�possib:l"y converge to a
value of -0.9 ars the pl-riod og record aj)proachr_s1.00 years-
3.)
ears.3.) the coca `,f is i Drat u skewne,s, dotal d po t on tiall (minor prota-
ability) convorge to a value cif about �-c_.0 as tile period of
record approaches 130 years or more.
,j,his results in the obvious conclusion that a genuine -regional
skew does exist, with a value most assuredly ranging between the
values of -0.6 to =-1.,.0,
in order, 'to arrive jt a value that would best represent the actual
value of the regional skew, the following- evaluiat;ion procedure
was utilized:
l.) Tasting of the five longest period -of -record skewnesses for
statistical significance indicated that they were all sig-
nificantly different from zero (90% confidence level) . Ac-
cordingly, these pivotal points on the convergence diagram
all represent viable skew values.
2.) The skewness coefficient for Big Chico Creek ( weighted "ex-
cellent" on the convergence diagram) was statistically sig-
nificantly different from zero at the 99% confidence l+.�vel.
3.) The anomalous positive skewnesses for Little Chico Creek
Tributary and Wyman Ravine Tributary (weighted "good„
on the convergence diagram) were both statistically 'it -
significant from zero, at the 00% level, and d.o not
represent viable skew values.
4.) The average and median of the skewnesses for the four
long-term stations weighted "good" and "excellent"
were determined to be -0,71 and -0.79, respectively..
These were subsequently tested and determined to be
g
statistically significant at the 990 � confidence level.
Considering the above evaluation along'with the convergence
trend depicted. in Figure 11, a regional skew value of -0.75
was selected as being appropriate for application of regional
analysis to Rock Greek. Although the data might indicate
Y
that a smaller value of skewness 'would be appropriate (ie: -0.9
or --1. 0) , the larger value of -0,,75 was utilized for conser
vatism, in that larger skewnesses produce larger flood magni-- I
tudes in the Log Pearson Type Ill dis,tribuLion. Additional
evidence toward conservatism in skew 'selection is
realized
when full consideration is given to the natural skews of the
7»
3
Little Chico Creek and B'A.,j Chico Creek (the two mosL-
similar sreafas Lo Rock Creek), which w( -.,r,. -1-34 and -1„27,
respoctively, Had r.-qwnal skew selection boon limited to
,these two station. -3, � �mmonsurately lower flood magnitudes
would result.
Peak streamflow characteristics (2,5,10,25,,50,100 & 200 year
recurrence interval) were determined by Log-Peargon Type :III
point -frequency analysis for all tho stations shown in Table
A, utilizing a regional skew value of -0-75. 11hese charac-
teristics were reduced to un it discharges (in cfr;o per square
mile) and related to a function of drainage area for evalu-
ation. Utilizing this information alony with the mapped
geographical trend of station skew variation and historical
information on peak -flood seasons at each strA*.on, all obvious
snowmelt flood streams were eliminated from the flood data
base. Theze included Granite Creek, North Fork Calf Creek,
Summit Creek, Scotts J'ohn creek., Grizzly Creek, Butte Creek Ca
Butte Meadows, Deer Creek below Slate Creek, and West Branch
Feather River. The elimination of f -hese, substantially reduced
the variance of the remaining streamflow characteristics
(as related to drainage area). Purtber analysis of -the re-
maining data indicated that most of the residual variance
was produced by one stream, Gold Run Tributary. Since the
soils and geomorphic framework of this valley -stream basin
was anomalous to that .of the other reifiaining streams (and
Rock Creek), it was deleted from the flood -data base.
Evaluation of the relationship between unit, peak discharge.
(in cfsm) and drainage area for the remaining ttation8r depicted
algeneral agreement with hydrologic theory in that as the
drainage area increase4i unit peak discharge decreases. This
was generally true for all station,,,,, except the three smallest,-,
Little Chico ,reek Tributary# Wyman Ravine Tributary, and
Shingle Creek. This ihcongtuitYp counter to theory,could
'not be explained on 'the basis of any regional or basin
characteristic, othor than sj,�Ill drainage area (0,62 to 3,,25
square miles)- Further invoOticintion suggested that this
jtjcojjqrtjity could probably bo attributed to a combination
of the short period--ref-record for Uleae $Lre,-IMS (II to 13
years) and the method of gaging (crest -Stage gv-1900-
0
Since those stations represent the bulk of the data avail-
able for very -small streams (the next smallest being Little
Chico Creek with a drainage area of 25.4 sq. miles), it was
decided to retain these streams in the data base for the ensuing
40
model and to attempt to apply an unbiased adjustment factor
to the individual station date. After, several failures in
locating such an unbiased adjustment factor; it was noticed
-that the application of natural station skews to the Point -
frequency analyses for these three stations improved the
results dramatically (ie- towards, accord with hydrologic
theory). Accordingly, the point -frequency analysis
for -those stations utilized natural skewnesse8 (ranging from
+0-43 to +0466) instead of the regional skewness of -0-75
employed for the remaining, larger streams. The latitude
for this cavalier,adjustment , was deemed reasonable and pru-
dent in that it: 1.) Would increase the magnitude of a
poak-flood event via the employment of larger skewriesses;
2.) Would be in general agreement with hydrologic theory,
in that the smaller drainage basins would produce'the larger
unit.discharges; and 3.) The resulting data generated for
those very-smoll streams could later be eitber disregarded
or reco,,iciled for in application, since the .drainage areas.
of the points -of -interest on nock Creek are in fact much
larger4
The resulting revised flood -data base consists of the streams
listed in Table B. These nine streams provide a.combifted
gaging history ,of 300 station, I -years (including extended data),
and range in period -of -record from l3 to 62, years, individ-
ually.
I
Table
Dx ainage
Araa.
,rte � .
—1-Al—'r(�Gacr.
Yeas
o
Mi.)
Little Chico Cr, Tx� bul;a.ry 0.62
rt
ate
1'7YMan Ravine Tributary 1.72
.66
Shingle Crock
d-0,43
13
3.25
Chico CJ eok
•t•0. S2
13Little
25.E
Big Chico Creek,
-1-34
�
721.4
Antelope Creel -,123
--1.2 7
48
Mill Creek
-0.89
87
131
Butte/�y.L C�ree
-0.46
50
147
Deer a e); .
Dl,
^0.65
4�
208
-A.52
62
Avorage: 79.2
Median: 72.4
33 3
37
N'atu3 a1 skcivs presented nor information
only. neier
text �'o., actual skeiv(s) utilized in LoPearson
9
to
Distribution
Type
III
( ) --- ,extended period
lop -a0-
The hydrologic region containittt these stroams is fairly
vjjjgorin, ar, all. are prodom.inately rain-flood itraamr, dzr i;Lncj
0 btv,sJ.nn of a rAmilar gooloqic, goomorphic, and L-opogrlphic
f,r�,jmo,j,jor%. Nome of: the larger basins probably have occanion
el mixod-flood regimor, (combinod rain-Flood and onowmalt
flooding) as the h.oadwaters frequently originate cat eleva-
0 tions in excess of 5,000 feet. The geologic framework- of
the streams is reasonably constant', since they drain
(with the exception of Shingle Creek and Wyman Ravine Tribu-
tary), areas predominantly consisting of Pliocene extrusive
0 volcanics of the TU81can f . ormation. Shingle Creek also drains
extrusive volcanics, except they are basalts of goologically
Recent age. Wyman Ravine Tributary e',nbibits the greatest
geologic departure, in that it drains Recent alluvial de-
4D posits 4 It was retained because it produced the largest
100-year unit-peak discharge of all the remaining streams,
and lent to conservatism.
Otbei, basin characteristics, such as mean basis elevation,
percent area above 5,000 feet, main channel slope, ond
mean annual precipitation, were variable, but generally,
clustered about a regional norm without excessive departure.
These characteristics are shown in Table C.
Table C-- Summary of Basin. Characteristics
Drainage
Mean,
Area
above
Main
Channel
;dean
Annual,
Stream
Area
Elevation
5,000 ft.
Slo-oe Precipitation
Little Chico Creel: Trib..
0.62,m!2
2,500 ft.
0./
290ftjm -i
65 inches
layman. Ravine: Tributary
1.72;
100
0
10'
Shingle Creek,
3.25
2,800
0
330
35
Little Chico Creek
25.4
1;400
0
150
Big Chico Creek
72.4
2,300
4
i4o
63
U Antelope Creek
123
2,300
16
l50
36
imill Creek
131
2,800
31
120
43
Butte Creek
147
2,700
28
15.0'
Dee: Creek
2:08
2,800
34
100
47
The various relationships were then evaluated to determine
Development of Model -
Peak streamflow characteristics (by recurrence interval) for
each stream in Table B wore initially related to the respec-
Live drainage areas by various forms of linear-regro8sion
modeling techniques. Drainage area was initially selected
as the independent variable since numerous &tudies have
shown this to be the predominantly significant basin charac-
teristic. Model forms included logarithmic peak vs. log-
aritbmic drainage area; logarithmic peak vs. arithmetic
drainage area; arithmetic peak vs, logarithmic drainage
area; and arithmetic peak vs., arithmetic drainage area.
Those relationships were prepared for peak streamflow charac-
teristics on a unit discharge basis (ie: cubic feet per
second -per square mile).
The various relationships were then evaluated to determine
the best model form, resulting in the eventual selection
of the logarithmic peak vsarithmetic drainage area format.
The equation-of-bost-fit was then determined for the 100 -year
recurrence interval model and correlation statistics deter-
mined (since this is the peak event of particular interest
for this study). Graphical forms were deemed adequate for
determining peai characteristics at lower recurrence inter-
vals.
The resulting model equation for the 1'00 -year peak flow is:
8100 =2 243 exp (-0.004 D.A.
where, 8I00 = the 100 -year peak flow in cubic feet
per second per square Milo (cfsm)
and; D.A. = the basin dr,ainacje area in square
miles (mi2).,
3-
11
El
0
a
(r2) of
a co
OX*Ml-k Or' 0-0190 lOgEnrit-11miC unit -r,, or
+4.50,4 and -4-150% (III)Por al -10 IOWOr bounds).,
Tba rpther liigh cora-olition coo:zf-icient and low 1,-t&nCj"J,-d
OrrO37 are unusually good for thin, tYPO 09 Modeling process.
0enerally, cOrrOla.tiOn coefficionta on the Order of 0.85
and standard errors of + 20% Would be considered =cellei-It..
Those results can probably be attributed to the homogeneity
of the hydrologic region, and the various model forms
evaluated (eg. oemi-logarithmic). 111, retrospect however, the
low o-tandnrd error obtained is probably superfluotis in a
strict statistical sensO, as normal stream -gaging procedures
are limited to an accuracy of about five percent or greater.
Calibration of this model (iereversing the prediction
process) With the 100 -Year ricak flows ;For 'the ,,,treams listed
in Table B, resulted in very low percentage error: N, as ex-
pocted. The model predicted the 100 --year peal- fj
o vis w i t h i n
2 percent (for Little Chico Creek Tributary) to 9 percent
(for Butte Creek), with the .Iveracjc percentage error being,
4 . 11 A b
Vl.ith the lovi standard error produced b the model using ing only
drainage area as the single independent variable, attempts
to ref-ine the accuracy of the model via inultiple-regres4:;ion
techniques and addit-ional variables would not be Warranted.
However, in 'the interest Of completenesso additional correla-
tion, with other basin characteristics were investigated
(see Table C). This process did not result in any additional,
significant torralablo basin characteristics.
The r0ZuItinCU 100"Year recurrence --interval pealt-flood model
is shown on rigute .8.
a
171
11) 77:
r' I Q 0 d qu. ncy
for UncJogecl I'latcrObOdS A Litaratuj:e Evaluation; .U.�.
Do),'iaa:t-ijjej*jt Of Agricultu).-o 136P.
Aron, G. and MiIler, 1978: Adaption of plood 'peal,
'Ind Design Nydrographs :CrOM Gaged to NeLirby Unq,,:LjL, Water -
Shod,", ; Wat
er Resources Bulletirl, Vol. 14, No. 2, PP. 313-321
Chow, Van. T.
(editor) ; 1964: Handbook of j1pplie4 I-lydrology;
McGraw-nill, Now York, 29 sections
Haan, Charles T.; 1977: statjsticaj .Iothods in I 1_1ydrologyi
Iowa state Univex";-4ty Pre8s, Ames, Iowa, 378p.
Hardison, Clayton z1.; 1974: Gener.-Ilizod Skew C OcEficients of Annual
FlOOdr, in the United gta
tes and Their iq�,plication* T,7,
Re5OUrC0,9 Recearch Vol. 10, No. 4, pp 745-752
"%proy:)zj-9, 'C'rV7in' 1970:
Bruin; introductory Mathematical St
LTOhh Wiley & woo
nt,,, New York I 470p,
Potter, R.G. I et -11; 1967: Sacramento Val ley D, ast Sic,
"'Ve8t'gationi California De
Bullotin No. 137, 299p.
Partnt ent Of W ater I Resourc'es
Riggs, H -C.; 1968 Frequency Curves; U.S. Oe.010gical
Technique,-,OfSurvey,
Water -Resources InIvestig--it-ions, Book 4, chapter
A2, 15P.
Riggs; 8-C-0- 1973: Regional Analyses o:e Streamfl Ow Charac,
toristicsf* U.S. Geological Survey, Techniques of Water_
Resources Investigations, Book 4, Chapter 133, 15P.
-16-
*WAR=
$oil conservation service, 1076: New Tables, of Percentage
Points or, the Pearson Type :01 Distribution; U.S. Department
of Agriculture, Technical Release No. 380 17p.
Thomas# C*A.j Haronburq, W.A., and Anderson, a.M.; 1973.,
Magnitude and Frequency of Floods in Small Drainage Basins
in Idaho; U.S. Geological Survey, water Resources Investi-
gations Series Noy 7,73, Glp., 3pls.
'U.S. Geological Survey, 1961-76: Water Resources Data for
California, U.S. Geological Survey Annual Open -Pilo Reports
U.S, Geological Survey, to 1960: Compilation of Records
of Surface Waters of the United States, Part 114 U.S. Geol"
ogical Survey Water -Supply Paper 1735, 715p.
tJ.S. Water Resources Council; 1977: Guidelines for Deter-
mining Flood Flow, Frequency; Bulletin No. 17A, U8WRC Hydrology
Commit -tee, 8_ -sections + tables
Waananen, Arvi 0.- 1973: Floods from Small Drainage Areas
in California -- A Compilation of Peak Data 1958-73; U.S.
Geological Survey open -File Report, 260p.
Waananen, A.0. and. Crippen, 1917-6 Magnitude and
Frequency of Floods in California; U.S. Geological Survey,
Water -Resources Investigation 77-21, 96p,
Young, L.F. and Cruff, R.W.; 1967: Magnitude and Frequency
of Ploods in the United States, Part II, Pacific Slope Basins
in California, Volume 2, Klamath and Smith River Basins
and Central Valley Drainage from the Past; U.S* Geological
Survey Water-8tpply Paper 11686, 308p.
17-66
fi
r.
1.
1.
f.
rl
1. YI
ni
fr
fi
Vi
I=
w
I w
a' r a-
7=7
'4
41
1.
yV
is
PI
•
l it
wr
X1 fi
td
'A "T"tea
W7, ;�-'•.
•
1i.
1 y
7,
q -p
, I . , . :. " � V� . , "I , 1, � , � , , I.. 1 1, 1, ". - .., '. , ,, , ", " , . I 1�1 �t I .. - . � . I . 1 .1 - �. �. � I , , . � .1, .. p 11 , 1, � 1 .1, , " . , �. I . . ;." . , ..j �, .1 1 . I 1� ""I I" '. I., , , '' A,
14:
71
21
"lip
'4
.......................
W0111111111im
. . . . . . . . . .
ELEVATIONS IN FEET (USGS DATUM)
205
LEGEND
--ORIGINAL GROUND
200 FINAL CHANNEL BED
(D o 0 100 -YEAR FLOOD ELEVATION
'(FOP PROPOSED CHANNEL DIM
195
190
.12,000 11,000 10,000
IN, 1111r, -,i j"
X1.
�•LtAL
0
: 1 M ,. 1 r ,r .. - 7 • , r, : i �. ,, 1 r r ILS •V
1
-
, a i
.. r.n... i-. :.. r.. ..... t. f� :, 7 ♦ ... Y! .., r .. A' , -. .ir :. , �.. ._ ..:. J .. :tl .. 1 L. A. ..'C�,. ,f+ ',
fin ... .. :., r„ .:. ,m.• 1. ... ,. ! .. ... ....,,�. „a, . ,i,. •.,, ,,,:. ..n....c\.. ;a 4. , •:4 �'
t ,y
t
A to
t'/ • ° ° i�,,Srll 11•
f
a4
i
ROCK CREEK FLOOD- DIVE'RStON ALIGNIMENT
PROFILE: INIUD CREEK to POCK CREEK
• e 1 \'
• �.0 PLATE •
,
i
•r
d�
,r
' ® 11
fr •,: , . i
I,•
f♦,
r 1 \
REACH
1 w
+ r Y
, e' r .:v. : . r i. .� :i. '.. 4 :,: .. ,' .• ,. .1 ti... ,. f •'. ': C,n. i ,r, I.
1 U
:, r : , '; ,'' a -.,. i. ., —,, v • .: � y ,. .. .. .. ,,,
.. ,. , Y -. �:- h. ,. 1. .. n :. , r •. 'Yt. h :. r--. M. a �
} t
.....:u sl.i: . _ .., .. �. .._,.. .. ,,.,_\:.\ ..._.. ..... �.. ,... ... .. -... .-x ,.. .__... -._ �s.. .__... ,.. _-....- .,_. _. s__. ,... ,� .._...... .. . .... .. �L ._-..... _.. ... _.. .. ._.._. _.. .. s ,....... ..._.i... _ _... .. _....., -. .. ..._._... .. .. �. ...,:a4 _,. .._ -,... .. -.. "�'d`&��a�•,�"tY,. .--i .... .. _..___ ... ..... a. �+.: .. .,..t. .3-.. _1 -._
MUM �Y aYa .+ P a +' ;v r3 r. w..; ly 1 4 t 4 I to a " a la,<`.f a 41A ,r 77th
]#d,f n a ' u. t I § 'r , ) , , 1 4 I t � r ,�," N !
tail A p7a d ,�,.- I ,ti ter# f }rr} ,S s r +ar rr t' I i) :`ai I n 1 / "�+ a ( 1 'w
yayl�lm shwa kF 7: n $r,4 kI # a e'1 r4 a cµ1
ywo1 ,! 14 I `, li r ! d _,Y �yi ,i I� w .t {,: a .N �;ft !Y tl. 9 :' t I tt. MOMMA, VO ,' a
T '�� �� l 1 I f l , I I a w r .!( i k ._aw6 11 . I i 'r.., } w! A Mil i l �+ #+?
f t 46 44 k 3'n
Jp +r Arrna.. A i. d rh.J1 t IAt , r,' 1^. I .' i 'o d t 4 N1,}. r( a Y Y l,.
i i q sr, _:: 1 , i (, /1 ) a s r' 1I! A. a `i !, :
`� ,l IC ;S ! p r "h ��'1 Y q 1. 1 iS t , r} er5 ,7 'r r r f e.° { ro 1 �F �rc;
f t! Ja An, r P I ,� I s t' l ,I7, a a '+<� � �a n r J 1q
I"I w 1> 'NI �Y i d ,� Y 1 at, 1 )". r, r �I k s d y P L6 r Y I y a ,�� P�11 ,. 'YI
`dtif +IAS n rr u A%%1,1`,+{ , a I I 1
e} l 4 4 a 1b r, I a;l 1 11. r � J tI f- r i II r�tjk'I 1 11 itt i
'�7 ; a tl p}'� 1 a u! ?} YS r t a +,; i t I k 1, r✓ r a n, 7 i I � r as
r v," I
- i .� A ,. r a r r i k q t� o rti P t 4 t� ✓ ; Y :� - +r1 Y� i g rSalyY r a a�' r
�� r , S�` n ff a r k ! k a f. Y 1 4":. ✓ "P ti , <, r r a as 1 1 V3,
F r l l rT d1 T+ P ii1 �.
I r `i yy ,j ? �a r+� 4 t r t I `i y x �'. irp tr�1 ,) , kY�
6 "1 11 r - a, $ as $ 'I a r. C ,. ':,: r' f C : , l l r Z k' w t' 'd i.
4 r a! a !. r ,, 1 1`. a l r t r r �)� 14 n' ^ t di I x C� @ I pa' i 1
,r r e k i n, o " t.i9 ,
kr �, N ,. +r1 -/, w I �� wn. di 17r S 7w �.^ ! It 'j 1. 1 ra +t r a .
I A a Ip' I a Y,' } rh r 1 yt p t r'.� 1 {iAi r 1 r A + �'r �M { �i tV` ,dk' ", r,
ACUh�s 1 1 d .. i ,I z r i�.' i r �} i/ 1� .r„ a 'i r� �'!:
jxf� ),l'. "l .t4 Blt 1 , 'w{1 FI f <<)"IpfOrf� ,.
p�� � 1 , t ri 1 S h r i 'tPCl rl �' �f"j {b
}"y�88 {S�� Y7 1 a o j. d ' P�, 9,I,q, w }4@).1��1 x, ,, u z r�a� f T t��lY, fr�G a i 4S r � 1 err It i.iw, }' I,�w4 l Il �r l },k t'
f' '11r t , 7 kLi la R T i` , T aM.+ . Y 4 iT, YAC : } 1 I r ! ° 1 r ,t . S v V ,�i a I
? r 1,Iii , 1 �Y V Pill I a It R 1
M C I f r a t i �r Ir ° If M'".", c �` ` ; r t j ICr, � " t N Y+ lS1 k q t' 1 t r "P� 1 4r'`� `Akrw A i",t C;
'1 I ry; i ! L 4 e r #�' ! a P r Y 1�,}+ ,)r y
d IiS ! wl1 r a { tf'tl�f,. tip I ,.I ,srrti r h Hyl y f»a y Ol.,h�e w1, a r i 4�,
yp{p 1 t )y a jV ,w + , r'� r ! { 7 el f {,1 ai { �' M r r<t in ! � 1k t
I 'tt t ,(k 1 y.. a! f I t r 41 � ,� - t 4}� °r )}; k r ° ✓ °Tf � Y r` d e� T r r +(1k r 7 i r rr:
a �4' .�y r ! rl l ,i. t 1'';'37 6 f fti r: , � e w t Hf , Yr a i �, irr tr 1 I � y�
L R} 4 �4:" t v r r t r Y r�, ! r y.� 1 i�'r:. 6 r, �a 91 wd,. t o f ,, " {`
�> 'k ai fq v r t d� ''✓ r t NY 1 -,I�" i a r 1 a4
.1� i 4 c y of p4`p1 f"t All � k Uhaft,? ker� 4r h� �'Sd�t:
�. P P+a'(`fk�,i a t a i'... I° M I7, 1; ,q,, t� ' �"11 �+�/"" fy I-ti P� M ^�r� t �.JSjs t, fu"; 1) .}I1�n �1� iti r I �6i � .`k 'd'gia,,9y�k"
"I�y \1 ;'♦;n Ind aN 1 " q is{{ l� ., `,li y I1lc a :y}' l r, { Y. �r w ��- M k ' l r a .!'�.: a 1� Y, w,�P-I� y 5,)� J Y � P y 'r 1� .,'`( ,I y�:VJ i,,,� ,�. rY
�I A,11".0..�a4 , i{ df t.i � M I�lYTi { }i1 It', r�li.�Y ,`i, , l wi r - Y,- -,li—' , ..,,a„,„d+:r.:1.�,,,-.,.it'..,..«..,, �..,..r� «>..-,..�., ,.. ,a s , , �r f� . rY Jw "P 1 �j y }k � �( r` A kdl} „
�a ll k i ` iii6 JIt9aq 1 �#iF!% �Pa Z1pl dda 'sl - ;t R � 41 , k t d{ 4 i�w�e , r,,.
xr y j{y�f..y b ,Y 1JS rt f �;y;�j}y eP,r/d'ry 11'1 4a ,(y.r ,k, *t }� ryY 7.- -..r {, ryt (y ( q �y {� y �r �t t;Y a7 T 1!'i its
r�,r ,r k. r1 ,, 1r �' liFa4 i"4 �Ikl
V ! 84� R tt 1 'Y lrpM �' }`i7lail f: ?L 1 �1 lJl\,'l l:V �fli: �R i[! TN!T Y(VI �`4
Y to Y S a< i A ,,1 a t+! 4f ..Y Ve l i II �'a i' d i (l �. jl F .
Id r d k f" I . d N d � r
5 T pd ! i k f'y, r'� + a , y�'r "s : . yfl tl 1 ii,. ^� ) w ” '. R y✓ til � r I - r .�:
{ w r<i c a r �( dk y , 1�4V1 d 0 P. l Z..1.t�i ,�1 r i t 14 Yi N 1 � k r h
✓✓11�I} M J )MOA
1d i 1} I �6 rd ali. a"} P r. Ir� x 7p a i k, !1 t o t h 11 51
'1{tta T, ill 1Fv"} �' 91 y f i ' Irl 1 (111111�,R `HM t �I� HHK 1',REA " !� ki 1� a Ili uk�I y.� dw'4a,�yp I d{'p {� 1{
fww,�)�"'Y .r 9 IA � " e' 1 6 ,d �'rw'al rI��<-4Il Y �' i�ax"i� p Mlr'pltrPl y' Ar + 41
1,>q k �z MailirI In, d F eY rw lk. �i }'k �}j l' }/' 9fl'1
��i ,! y�} �yY 1 DV i" ay t i y r )ail lr 1 k a r Y:
r y �$ " �} �E�r 1 I St � .r (Gr 4,,, I d r 1� ,i'i'r� i
}4 ;.hi .! r -, ,- r la,�, $ P4, v+ ` �Nr ry txJ J - J
CAN A' ba'4 ry 1; r�ty d Ary yr a{ k ,.� ,rk i lrr 'r 1 Pv, i r " f1 I r 1 - # T' I I l
IIkd, rat 1� {�1 1 I".1 I ,✓ 1P�i f _ a a [+l I 1,t�.fli� k �X" A gf-alb t.ttjtfv', $frli�r,
'I d ''a1'yh �r rf rin I r ,:'.l i s.. ''E i r�'IIt I�N, iin,�Itl piir r.-�y"
�' I, + 1 x i, fi 't 1 } at ' i " 4) # i,04, f iy .. r it 33 ')I! 1fi�1y'i
?.f w a' I f{�) - a. ( 4 ' 4 a, A a' 1 ,�F 4 r Oar r,V
�I y)ly �jl;lr r t ,;fix" � �' S"%I� Iii + ,a, t � o Jfli " ! i f r `�I ��1�}k Y a
�1r9il t ' a` .'" a �' ,� I.alt ir, it F?�' ,I,1d J 'k✓ .Y ! 4 tY A;., rl y t la 1 x, w it �' ry"a � i 1 i,l ',��� a 91 ,.. a r r� V f r tf ,,.Y ted 'dd�Ay%
,,)i I O, a., Y � t '� -_,t w 1 L 1 1 : d >' ,✓J w ' '9r'd 11 . °'"r "I,,,,
9 A ; .`I h; 1 �" l ✓ P a i k l r ,+ r 61 > a1 l r s
OIn 4, rt � vl w ±. �Iy J:
J a, r �> w ati l wj � a
9 A. y} 1 t 7 r }w 1' ° Y ! ll I?'.
J d, t f ld r ,.. I r p id' S 'h 4 A n �'� Y f fy -S a 7' k tt 31+" i'
A W l ,{ s 1 '�., r � 5 C' r .1 11 Y T t 1 y r" I 17 d t d J
�. < 1 7 ' - �a . Ii 1 F. 4 y a I, N}y J 1 �t a l a a.,.
' 4g A, l ;If J✓1k,., a T ( i* r f I. I JJ {! r
I. vrr�) 1 li i S u ,". Yr xdd a rt I to h { �. ,Y'y a�y 3T Y{� r a r
Yk I a"1l C' Y a_J'' ' I l V y �rp 'iiia" h ) P! 1 r
ft �r II
,�r w r d�' " r P' d atr Ya , � ,A k � � I, I r � tail ,� I 1 }F V �ti .y a r
i
. t - `(} p a t �,! '.ya. Id 1 f r d *' yj`, y �:) fi `k tPjF "y, ri ey '1r t h I4
q ii Pl �1} tP: �'`' q 'a alar A pp44Ij 1 ;w
oil Yy T `j` a l ih 4 1 t' „ 1, f a l#wl ,' I , l ." , 4 a k 1I r-0; a e r a k'
r ,� ,
i AI k �; i �, , ,
1 .d i� I I t Y Iyk,.) 1, �4� y`I
d �° } s 1 r{ qy , ,II 1 u °� a N' k } T ��r 1 t
I�', i., F y e b. r 1 I, k °i ,. qq �. I� r I, I =,t. 1'"a
I E-I l i At a Et• q e Y a I 19 i t- w i r I i
l s�'� M p ,a � s ty t ,, , �� rr i q A t r, al 'i 'd r ",
i y� ( 1t r 'l Iil I , i[
I v J d d d e� �N r+ U° 6 w{ U 9 e I R! f u'
,errI� r tW I I"v<�d Y w 1`i'f r/:", , rr Jr'I'; ,A a i 11$ t1 „j
'� P I, P: r }y k z i I
0 ,s�`}}a :y y1� l� yr , !c r ,.a y) I�{1 Ohl' ' a�� "i 1 Y or rydx}�'�7 h ±A.,w1 1, ��� 1 11, 1.
t rl Y1i,F
t' � as, SOW d Ifla � a I! 1 Y t .t .Y; l } r i ( f avy i "�. r! a 1 M1� Y 1 l r, N
iT ry I }r/ 8, , i r raaf , ., r a ar �."f YtY{{�, LIS �`. r3 r ` tk '.0 d 11 i },f- / hl 1 q 1� , r r t U
'), v . , fl w y , M v, pI 9k' �' ! f "'�, A , ' °t _' y ,
V al 4 I 9 I 1a rrk q.. � 'a r V 1 1 y�:� J - a Y' K "h 1 I di ,rJ ",
'a i 49+ Y ',,w Cy P.` r a��'}� V, wka ✓.,.I YI Y„ A iraP ��. r)wkh e,1 da '} ^ ' ;�� 1Y l ry,r iIr a},�.�r}�
r rI1 i,V ,4 r ' ,..Y 11 ,7. aro sr1{, lr , t T1y ,7} a;d k ) I:I I,ty rl" �!4yl Y k. !� 4 4 7 r w ',F
r, ,"j),";
a;4 A t , lir ( "` '11rr 4 flri>r 1 rMf d Il cl �J IPgr } rJ 1i�
C11 r) la I y ".,rw ) ,: v I , '�1yf a r a f yw�� bw.�
y)r , S y,ql� y �{ r !L, �Y $,.1 � tla ", � � i' Y i "'r ayy Idi � +;S
ra 1kOr IJ 4 _ 1! y� * 1 r rdtia r I r. "v i U , I_" �y 4a �, ,Ir �rkrld }f 7fikl+ll,rI IOW i7)4 k ,,.,
Ov" " } >Y 17 m�Ptl wl ,xp d f':4 (p, _1 rt ¢A au1 '� ,, U r. I1tiM fir; k m "u',
,P 1 :d J'* 1 4 PAr" Y A I�{� d eJ dr t. i I., 91G is ,.g I }', 4 .{rk k1p )4.@: aYy�BM 111 ,�I Jv d .gyp "
`4iA nkat �. f UIn,., ',r14e .�i a:d a f�, tl'j,klr a! �t I I! 't, t Y1t ipCi ja�yF Ltf
k`, f A., 1 Y� A9 a i" �__ s, 1 N 7� ,_ t; 7 K , 4 1 I y 1 ^° r h tr~' >r ° i a V.4
�', 0
� I
a k rri xyw a a ",: 1a r „ r 1 -,{ i, a 1 k' �', 1,, Ra �r �,+ } �I f 'A siU F 6'
" tl w
71i t1r:) , " ,, t;, i f �! y'rr �, .t$ l tf ,,' �1 "» a` . 1 1 Ki a
' �h r W , :yf., . , I rl { i M ,r u l (,11y. y "�{$l, ( ,
( it g r vM F� rI .r' If a r P r I f ✓ it
Q t F^ , w 1 a i 1" .� I v 1. ,,
rrr� t , >�Itr altl iilrra r7jqqu q4 I, y), r)
n rtlA r i )�`I1}�w g }r �'. �� a r �". 11, I"
h' p 1� T r i1 ����}�") 7 L s,
4Y #� P' y�ylS t k. + 1 r. a i �'i I'.."" ° t r i )d;'i1
r )kr 4 iUr4Yl k f ,? a � n;� r, ..,v 1, y r A # r Y r y`St .,p 1 �,. 'dw}� v v rPi�t ', ''
irl A
,�, Pyt) 4 R✓'I �o R ''.'1 a u r rr, �,, 1:" "if, ) M , 'r
�y�41 fiw kf 21t9 k d7 14 7k }! Y� - i k� r.,� P A k� 1 a
r P t ,a I Yr h9'q
�" ,4 y �,J °�, ..p r w ° ,!ki. bL J u 'i Y ,rF r 1" 4 9 rl , A i
t �It Rk : I 7 �I r Y it ,t"„ ' �,' s 1 a ,1 p x�� .fi
b !10— r 11 a '' r� 1 .1 r �11 a +} �I . 1 y°°i." waw "'.. ,}'rJ
r Y#� ( wi wk x «h a rrr '� er i Ii �' a J- }y I 1, .
�a ,gg , d
+[Ii a , 11. I Ir i lel .1 , ° BIW } C r , , q e r,ry I ?. t 1 M, f aj I Vri
v 1 i nl i r 4i, i )r ^� .� + aa1 II 1 , 1q .
M r r ' k p 94If ^ d�;H 1 I t �, 1,
dI t, w
ay 7d� 4 i r 'I � n�,) } ja i r " , ! P;, �� a r
x r N Q 11 I ) x 1, Y I J I w,A v �. f
:� n M J i I T k ,� 1 ,0-1 7 a Ir r f a s lyr I Z ,� 9 't rt d
! {qttr w ' a n r' l U e� o a 1 ,I Y" r ,I A, I .8 Y� t P i4 O F
Y Vr " a alnI Q NYr �IR ` t I 'i� w 4 `d r
� i p " to a, SII ? r } °+a1 '�: h1r1`i 1 1 I l < I: I r t, d U} ili }I T ✓� ' 1 0 #�, 11 1 b v ,t f, Y S'; 1
i+ �' ,r 9 1 'PI�� ,w �� .I 11 ;,yI g1 # a M x l, °,, "i " 'Z,,
t} ♦� r 4 y r7, .Pw'j ,q f ! 1 a• J r". d Q r, d° , A," SX ! kIt d A 01 ,t l , y 7 ,
Jv <A Y.,. ) ° A ar I I y J I } 11 a n+ %d I i ,-, r 'j iP 61 Yjy.
�, ,� f y l i" r, of k i j. r 4 6 l �r�
�111
q i. >, TYf� {r a a 9 I t[ i..t ,. " r t y 77. 2 ,r,� ¢, n 1 i 11 1 �t A e
" r a l�hf Elk r ,j }n. ° "V.+ r o.� 1 fl )"I I IT . l kwa t . f e f `- i f ", Iy ,
uT f ,(I'i r 1 y 1�0 17 . t r(Yt :r Y fl U ae w y v f✓, r s >«
" fwol 9r I f I r' w " I r. r r E1 A ry9 d a ;, ak Y r A 1, y :a
,pa {,J pp ,gyl ,I 1 I t ,c r ,.) I r q:' r,; 9�" A`a ' t a 1, 4
1 ✓�ligr: ! l r r{, 1 1r ,r1- r ,� l r j t r It ,� Y - r dl I 1 f t j, '� k
1 'Fr'la, }�} "I oAI r, 11w yt�
Q86 � , r .ii �° r v ' ,' j ll' e ,�� I a W r tCi T JJ', x t✓ �h�tr P 9" .it , as
!T>IC to t r 1 t ,{ I f r{i d a r{ n ly J Y r 1 1 '1
k {. h1 r t A�', < 11 1 r 1„ r 1" 'I.. 1 P ,✓ a y TI fi ' I -. i I q P 14 -
r wlµla + Ifa I I ) Y4 r y , .� R A. A r I� n '"; 1 o dk,.At a d� r1 ,� M04 1ar f CYN ,;
I1.s d
AaAyjLX }
t'i � e�,,�r� - C,%p, r.., yA;,a,,.V ,4rP. q,'I ui �l�"1 _�t%. - _, yr. r g.7'�: .. .rx �n 1, .N.,. r.,Y it ��..
t �.
q i N � %S �' y
} , � ♦
ia°
�
+4 i t'• a 7.:.f `'
l � t'fyF r� A4 �N a*r. • r�S 1 t j • � W . 1 � y �w��{ Y S f: 'h Ar 1 � ,,4V,'1
1 1 e r pS (+ ~. 7 ! { t t �[ yy � � � ti � '- � + a w Y �� t7 I
V �,,k •. r-T
a7 �'
r '
�"'' iii• •a' i
Fs
�h 1.
4
44 r
td
Y Y.
as
�rY;
7r1f:'
` C t
� �'11Lr• 1 �• �'
/�,
xt ,.
y
t a •:
f
yii 1
'TJy�at YM1�
t 4•
� • 1 agr
Y
+ 1
Fri .
s.,
a
.
,
4.
• • • � fl h� k i
• • V, ^�i4�t '
t ly
� ��
F t 1+ Y P
• ((Ay 11+11 vJ �{
6 ^a 7 >,•. [, ar 5 1 1 1
„1 4'r: i'r . la.. 7+^ ff:f .4. ln.N J
1. ; \� 1
N
r� ,.��v�: .,,;. ,.. ..•�.�urv�...
w �+. i 'i P', V v ,v .u-
.f {. 1:5a �. t tr n.V:' Y I r .:: pa t.f ` } ;'�ti:;'• + ! ..I.y V� .::1 N h r' .t- of
�i: :. •.7 0Y ,, , 1 V.f1,'.,-.'L
'.'7' yr )i. { }..��.. �A. %b �. N1 �..,,. }! y�,v.b�•.l '^aY ',i�nl."rJ � \ .4.: �,� +if :.M i y ,1r. �rr,.4,:Y (j ill, �: Y'. 1��y'e7'AIJA.%:#i}%t
�NM S ry4 t �v.:1{ 2 V ,�.,•, S 1, `i vS�4 P �lHti:;r
;;M �4 1 (l. vJ}1�' { LI'Fl 1`Pµ 1 i %." 1 I+V 1�-!%'4 ,Fi(1 4�y 4 4 t!', .•.t ; 3.{�.'(. }( t:, l.^ SII i I,IY..q,'.'r �'/? v '.,14
��,�. ��'�,< ,,._ a��, �� ��1.,.s>< .t,• _ �. _u ��t���.•��. „_�-"., ...�.,.�'`�� �.,� 11 . �_�u�.. �t �A_. w�� s r�_ ..,�..>�..�.�._+_�� , .�..__;���.__i,.��ar7
'J<'P1BL)i' OP CO1,4'.VS'NT )
Ra5a No.
PART 1 Design & Planning Considerations ........
1_1
INTRODUCTION
.. ..........................
Location ,..: • . .. , .... .. ...
Purpose &,Scope
� -1
+�
... . . • •., i Y i •
Description of Area•
1.-- 2
... .• .
Budgetary Limitations
....,..... ..
1-
CLIMATOLOGY .....
. ....... •
1-7
Gener, ai
._• ...
Precipitation ........
1-7
«.,. ... ...
hydrological Rami:Cica'tions
1-
...........
l -S
DESIGN CRITERIA
... ..... ..i........
1-10
HYDROLOGIC ANALYSIS
................
1-•lG
General .. ......... • .. • .... ....
�.-X2
Hydrologic
Y gic- Methods
....................
Empirical Models............
x...1.3
.....Y
1-14
REFERENCES ..............:..
..
1-18
PART II: Upper Mud Creek Master Plan ...........
2-1
INTRODUCTION
. . .. ... ...
2-1
CONCEPTUAL, CONSIDERATIONS
......
TECIINICAL FEATURES ........
.. .........
2-.3
Typical Channel sections`
2--3
. • • .:...... ;
Reefer Slough Design Discharges
1_3
......
Outfall Channel ........
2-5
...
Collection Manifold
.. . ...
Drainage Channel System
2-
Drainage Structures ...
2-9
..........
Project Cost Estimates .:;
2.12
... .......
Project Staging
2-15
•.:...,.
Preliminary, Assessment•Program
2•-27
......
2-,24
PART III; Meridian-Munjar .Master Plan
.. i ...... .
3-1:,
INTRODUCTION....
,....'.................
3-1
CONCEPTUAL CONSIDERATIONS ......
3-f
r�RC%INICAL FEATURES ,
... • . • ...,.... , ,
3-4
Diversion Channels ..,............
3-
Improved Natural. Channels .........ii•
3-6
Channel Construction -S� Realignment ..
3-.8
Drainage ,Structures ..:.,w . s . •
3-5
a . • . •.
.Drainage Out,fi'alls.........
..
Project Cost, Estimates ....: .......
3-12
3-15
.
Project Staging ....;...:..........
3-21
Preliminary Assessment urogram .... , ..
3-23