HomeMy WebLinkAboutHYDROLOGY REPORT TR 30496 PA 1, 2, 3 EXISTING CONDITIONS HYDROLOGY REPORT
FOR
TENTATIVE TRACT NO. 30496
PLANNING AREAS 1, 2 &3
(EXISTING CONDITION)
CITY OF LAKE ELSINORE
COUNTY OF RIVERSIDE
Prepared for:
PARDEE CONSTRUCTION COMPANY
108880 Wilshire Blvd., Suite 1900
Los Angeles, CA 90024
F J.N. 51.009
Date: 4-23-02
Engineer: Christine Duk
13re red Under Supervision of:
Peter H. Duk, R. . E. 3 , XP. 6-30-04
M'
BV ENGINEERING
CIVIL ENOINEERINO
LAND PLANNING
u
! LAND SURVEYING
ONE CORPORATE PARK • STE 101 • IRMNE CA FORMA 92606
(949)962-0617 FAX(949)962-9692
HYDROLOGY REPORT
FOR
TENTATIVE TRACT NO. 30496
PLANNING AREAS 1, 2 & 3
(EXISTING CONDITION)
CITY OF LAKE ELSINORE
COUNTY OF RIVERSIDE
Prepared for:
PARDEE CONSTRUCTION COMPANY
108880 Wilshire Blvd., Suite 1900
Los Angeles, CA 90024
J.N. 51.009
Date: 4-23-02
Engineer: Christine Duk
4Prred Under Supervision of;
Peter H. Duk, R.V.jjfi95-5—,EXP. 6-30-04
BV ENGINEERING
CIVIL ENGINEERING
LAND PLANNING
LAND SURVEYING
ONE CORPORATE PARK • STE 101 • IRVINE CALIFORNA 92806
(9")862-0617 FAX(949)862-9682
3
Introduction
This is a preliminary drainage study of Tentative Tract Map No. 30496 of the Canyon
Hills project. It includes the computation of the flow runoff discharging into
Cottonwood Creek, San Jacinto River, and to the open space outside of the project
site. Tentative Tract Map No. 30496 is bounded by Railroad Canyon Road, Canyon
Hills Road, and by open space.
Under the existing condition, the project area consists of perennial grasses and
bushes, chaparral, oak trees, mule fat, etc...(see the attached aerial photo). The site
consists of soil types "A", `B", and "C". Soil type "C" dominates the entire project.
The purpose of the hydrology computation for the existing condition is to estimate the
flow's magnitude from the offsite entering into the project area at the tract boundary
in order to provide a storm drain system to pick up that flow at the final engineering.
In addition, the hydrology calculation for the existing condition is used to balance the
flow leaving the project as required by UBC and the County. If the flow at the
developed condition exceeds the flow at the existing condition, then the peak flow at
the developed condition must be attenuated until it is equal to or less than the flow at
the existing condition. In that case, a detention basin must be provided to detain the
difference in flow between the existing and developed condition.
HYDROLOGY REPORT
FOR
TENTATIVE TRACT NO. 30496
PLANNING AREAS 1, 2&3
(EXISTING CONDITION)
CITY OF LAKE ELSINORE
COUNTY OF RIVERSIDE
Prepared for:
PARDEE CONSTRUCTION COMPANY
108880 Wilshire Blvd., Suite 1900
Los Angeles, CA 90024
1 J.N. 51.009
Date: 4-23-02
Engineer: Christine Duk
Prepared Under Supervision of:
Peter H. Duk, R,5,E.j 3 , EXP. 6-30-04
BV ENGINEERING
CIVIL ENGINEERING
LAND PLANNING
LAND SURVE V INO
ONE CORPORATE PARK - STE 101 - IRMNE CALWORNA 9243043
(949)862-0617 FAX(949)062-9662
TABLE OF CONTENTS
INTRODUCTION................................................................................................. 3
A. PROJECT LOCATION: VICINITY MAP,AREA MAP....................................... 5
B. HYDROLOGIC SOILS GROUP MAP: PLATE C-1.41......................................... 8
PROJECTDESCRIPTION............................................................................. 11
BASISOF DESIGN ............................................................................................ 13
COMPUTERSOFTWARE.............................................................................. 15
HYDROLOGY CALCULATIONS............................................................... 16
A. SUMMARIZED HYDROLOGY TABLE ............................................................ 17
B. DETAILED HYDROLOGY CALCULATIONS..................................................22
1. i0 YEAR STORM..............................................................................................23
2. 100 YEAR STORM............................................................................................ 57
HYDROLOGYMAP......................................................................................... 91
INTRODUCTION
3
Introduction
This is a preliminary drainage study of Tentative Tract Map No. 30496 of the Canyon
Hills project. It includes the computation of the flow runoff discharging into
Cottonwood Creek, San Jacinto River, and to the open space outside of the project
site. Tentative Tract Map No. 30496 is bounded by Railroad Canyon Road, Canyon
Hills Road, and by open space.
Under the existing condition, the project area consists of perennial grasses and
bushes, chaparral, oak trees, mule fat, etc...(see the attached aerial photo). The site
consists of soil types "A", `B", and "C". Soil type "C" dominates the entire project.
The purpose of the hydrology computation for the existing condition is to estimate the
flow's magnitude from the offsite entering into the project area at the tract boundary
in order to provide a storm drain system to pick up that flow at the final engineering.
In addition, the hydrology calculation for the existing condition is used to balance the
flow leaving the project as required by UBC and the County. If the flow at the
developed condition exceeds the flow at the existing condition,then the peak flow at
the developed condition must be attenuated until it is equal to or less than the flow at
the existing condition. In that case, a detention basin must be provided to detain the
difference in flow between the existing and developed condition.
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8
HYDROLOGIC SOILS GROUP MAP
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LEGEND HYDROLOGIC SOILS GROUP MAP
SOILS GROUP BOUNDARY FOR
A SOILS GROUP DESIGNATION
R C F C & W C D ELSINORE
HYDROLOGY MANUAL 0 FEET 5000
PROJECT DESCRIPTION
11
Project Description
The project site is bounded northeast by the existing Cottonwood Creek,Railroad
Canyon Road and Canyon Hills Road,north and northwest by open space, southwest
by open space. Its gross area is approximately 57.4 acres.
Under the existing condition, the entire project is covered with perennial grasses and
bushes. It also consists of chaparral, oak trees, mule fat, and etc... Soil type "C" is
predominating in this project site. However, soil type"A"is along the creek.
This project site is west of the proposed Tract No. 30493. It consists of Planning
Areas 1,2, and 3. Planning Area 1 will be developed into 200 units of apartments
which are approximately 17.8 acres. Planning Area 2 will be developed into 368 units
of apartments which are about 31.9 acres. Planning Area 3's land use is unknown,but
it has approximately 7.7 acres.
BASIS OF DESIGN
13
Basis of Design
A hydrology computation for this project is mainly based on the Hydrology Design
Manual prepared by RCFC &WCD, dated April 1978, along with the County's
requirements. The peak runoff for this project will be computed based on the 10 and
100-year storm event for the existing condition. Based on the RCFC &WCD, the
land use shall be the "poor condition"in order to be conservative when determining
the peak runoff of an undeveloped condition.
The runoff generated from the project site will be subdivided into several small local
watersheds. Each local watershed will consist of an initial area that is limited to 10
acres and a maximum flow path of 1000 feet as described in the above Hydrology
Design Manual. The flow runoff from the initial area will flow downstream to the
next area. That travel time for that area is calculated by using either the valley or
mountain condition depending upon the natural slope. If the natural slope is less than
or equal to 10%, then it is considered a valley condition. Otherwise,the mountain
condition will be applied in the computation of the travel time. This travel time will
be added to the time of concentration from the previous area. The total time of
concentrations will be used in the runoff calculation for that subarea based on the
equation Q= CIA.This procedure will be repeated until it reaches the end of the local
watershed.
FF
COMPUTER SOFTWARE
I
15
Computer Software
The runoff computation for this project site is based on the
CIVILCAD/CIVILDESIGN Hydrology-Hydraulics,Version 5.0,prepared by Joesph
E. Bonadiman &Associates, Inc. The software is designed based on the Hydrology
Dc°si un Manual prepared by the RCFC &WCD, dated April 1978, and approved by
the Riverside County Flood Control.
This engineering software is used to perform hydrology calculations and input data
can be entered in as either Metric(SI) or English(in-lb) units. The output data may be
prepared in either Metric and/or English units, too.
HYDROLOGY
CALCULATIONS
SUMMARIZED HYDROLOGY
TABLE
SUMMARY TABLE
FOR
DETAILED HYDROLOGY CALCULATION
EXISTING CONDITION
TENTATIVE TRACT NO. 30496
10&100 YEAR
Node Total Area Q10 Q100 Pipe Size Remarks
# Subareo (Ac) (cfs) (cfs) (in)
20 Al 5.85 10.9 17.2 Initial Area
18 Pipe Flow
21 A2 9.50 17.6 27.7 Discharges to open space
NC
22 A3 11.85 21.7 34.3
V Ditch Assume
23 A4 26.55 46.5 73.9
V Ditch Assume
24 A5 I 29.30 I51 .1 81.3 Discharges to a low point
SUMMARY TABLE
FOR
DETAILED HYDROLOGY CALCULATION
EXISTING CONDITION
TENTATIVE TRACT NO. 30496
10&100 YEAR
Node Total Area Q10 0100 Pipe Size Remarks
# Subarea (Ac) (cfs) (cfs) (in)
4.0 81 5.90 10.8 17.0 Initial Area
4.0 B2 11.05 20.2 31.9 Addition
V Ditch Assume
5.0 63+B4 26.20 46.4 73.6 Discharges to open space
36 Pipe Flow
5.1 B5+B7 29.10 51.8 82.0 Addition
36 Pipe Flow
5.2 136+138 29.95 53.4 84.4 Add'ition
36 Pipe Flow
5.3 29.95 53.4 84.4 Confluence wl Subarea E
11.0 E 2.75 5.0 7.9 Initial Area
18 Pi e Flow
5.3 32.70 58.1 91.9 Confluence w Subarea B
42 Pipe Flow
11.1 Discharges to Cottonwood Creek
2.0 B3 3.70 6.9 10.9 jEntering pr-;--1 site ro'ect boundar
SUMMARY TABLE
FOR
DETAILED HYDROLOGY CALCULATION
EXISTING CONDITION
TENTATIVE TRACT NO.30496
10&100 YEAR
Node Total Area Q10 Q100 Pipe size Remarks
# Subarea (Ac) (cfs) (cfs) (in)
12.1 C 0.45 1.1 1.7 Initial Area
18 Pipe Flow
12.2 Dischoraes to Cottonwood Creek
7.0 D1 6.45 12.1 19.1 Entering roiect site O project boundar
V Ditch Assume
8.0 D2 8.$0 16.3 25.8
V Ditch Assume
9.0 D3+D4 23.05 41.3 65.6
36 Pipe Flow
9.1 D5+D6 23.95 43.0 68.2 Addition
36 Pie Flow
9.2 D7+DS 24.85 44.7 70.8 Addition
36_Pipe Flow
9.3 Discharges to Cottonwood Creek
6.1 D3 5,00 9.5 15.0 Enteringproject site @ project boundary
26.0 F1 3.55 6.9 Initial Area
V Ditch Assume
27.0 F2 3.70 7 11 Discharges to a low point
a
SUMMARY TABLE
FOR
DETAILED HYDROLOGY CALCULATION
EXISTING CONDITION
TENTATIVE TRACT NO. 30496
10 do 100 YEAR
Node Total Area Q10 Q100 Pipe Size Remarks
# Subarea (Ac) (cfs) (cfs) (in)
31.0 G1 6.15 11.0 17.4 11nitial Area
NC
32.0 G2 14.45 25.0 39.7
NC
33.0 G3 21.10 36.2 57.5
NC
34.0 G4+G5 36.15 60.6 96.6 Addition
NC
35.0 G6 47.90 78.7 125.8 10ischarges to San Jacinto River
37.0 1-11 4.45 8.2 12.9 Initial Area
NC
38.0 H2 12.80 23.1 36.5
NC
39.0 H 3 20.05 35.8 56.7
NC
40.0 H4+H5 35.10 60.0 95.6 Addition
NC
41 H6 39.25 66.6 106.3 Dischar es to San Jacinto River
4 11 4.50 8.8 13.9 Enteringoro'ect site project boundar
NC
42.3 12 11.25 21.3 33.7
NC
42.4 13 1 15.75 28.8 45.9 Oischaraes to San Jacinto River
43.2 J 3.65 6.7 10.5 Discharges to San Jacinto River
44.2 K1 3.65 6.8 10.8 Entering project site ® project boundary
NC
44.3 K2 7.80 14.1 22.4 Discharges to San Jacinto River
45.0 L1 5.70 10.4 16.4 Entering project site @ project boundar
NC
45.1 L2 8.30 14.9 23.6 Discharges to San Jacinto River
FF
DETAILED HYDROLOGY
CALCULATIONS
10 YEAR STORM
24
Riverside County Rational Hydrology Program
CIVILCADD/CIVILDESIGN Engineering Software, (c) 1989 - 1997 Version 5.0
Rational Hydrology Study Date: 05/22/02 File:x496.out
-- ------------------------- ---------------------------------—----------
HYDROLOGY CALCULATIONS - EXISTING CONDITION - 10 YEAR STORM
TENTATIVE TRACT NO. 30496 - CITY OF LAKE ELSINORE
ENGINEER: CHRISTINE
----------------------- --------------------------------- ----- - ------------
BV ENGINEERING, One Corporate Park, Irvine, CA - SIN 705
------------------------------------------------- -------------------------
Rational Method Hydrology Program based on
Riverside County Flood Control & Water Conservation District
1978 hydrology manual
Storm event (year) = 10 . 00 Antecedent Moisture Condition = 2
Standard intensity-duration curves data (Plate D-4.1)
For the [ Elsinore-Wildomar ] area used.
10 year storm 10 minute intensity 2 .320 (In/Hr)
10 year storm 60 minute intensity = 0 .980 (In/Hr)
100 year storm 10 minute intensity = 3 .540 (In/Hr)
100 year storm 60 minute intensity = 1.500 (In/Hr)
Storm event year = 10.0
Calculated rainfall intensity data:
1 hour intensity = 0.980 (In/Hr)
Slope of intensity duration curve = 0.4800
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
Process from Point/Station 6.000 to Point/Station 20.000
**** INITIAL AREA EVALUATION **** Al
Initial area flow distance = 920.000 (Ft. )
Top (of initial area) elevation = 1741.000 (Ft. )
Bottom (of initial area) elevation = 1486.500 (Ft.)
Difference in elevation = 254.500 (Ft.)
Slope = 0 .27663 s (percent)= 27.66
TC = k(0 .530) * [ (length'3) / (elevation change) ] '0.2
Initial area time of concentration = 10.505 min.
Rainfall intensity = 2.262 (In/Hr) for a 10.0 year storm
UNDEVELOPED (poor cover) subarea
Runoff Coefficient = 0.821
Decimal fraction soil group A = 0.000
Decimal fraction soil group B = 0.000
Decimal fraction soil group C = 1.000
Decimal fraction soil group D = 0. 000
RI index for soil (AMC 2) = 86.00
Pervious area fraction = 1.000; Impervious fraction = 0.000
Initial subarea runoff = 10.866 (CFS)
Total initial stream area = 5 .850 (Ac.)
Pervious area fraction = 1.000
I
25
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
Process from Point/Station 20 .000 to Point/Station 21.000
**** PIPEFLOW TRAVEL TIME (Program estimated size) ****
Upstream point/station elevation = 1486.500 (Ft. )
Downstream point/station elevation = 1482.000 (Ft. )
Pipe length = 170.00 (Ft.) Manning's N = 0.013
No. of pipes = 1 Required pipe flow = 10.866 (CFS)
Nearest computed pipe diameter = 18.00 (In. )
Calculated individual pipe flow = 10.866 (CFS)
Normal flow depth in pipe = 10.42 (In. )
Flow top width inside pipe = 17.78 (In. )
Critical Depth = 15.16 (In. )
Pipe flow velocity = 10.24 (Ft/s)
Travel time through pipe = 0.28 min.
Time of concentration (TC) = 10.78 min.
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
Process from Point/Station 21. 000 to Point/Station 21.000
**** SUBAREA FLOW ADDITION **** A2
UNDEVELOPED (poor cover) subarea
Runoff Coefficient = 0.820
Decimal fraction soil group A = 0.000
Decimal fraction soil group B = 0.000
Decimal fraction soil group C = 1.000
Decimal fraction soil group D = 0.000
RI index for soil (AMC 2) = 86.00
I Pervious area fraction = 1.000; Impervious fraction = 0.000
Time of concentration = 10.78 min.
Rainfall intensity = 2 .234 (In/Hr) for a 10.0 year storm
Subarea runoff = 6.688 (CFS) for 3.650 (Ac. )
Total runoff = 17.554 (CFS) Total area = 9.500 (Ac.)
26
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
Process from Point/Station 21.000 to Point/Station 22 .000
**** NATURAL CHANNEL TIME + SUBAREA FLOW ADDITION **** A3
Top of natural channel elevation = 1482 .000 (Ft. )
End of natural channel elevation = 1466.200 (Ft. )
Length of natural channel = 360.000 (Ft. )
Estimated mean flow rate at midpoint of channel = 19.725 (CFS)
Natural valley channel type used
L.A. County flood control district formula for channel velocity:
Velocity(ft/s) = (7 + 8 (q(English Units) ~.352) (slope^0.5)
Velocity using mean channel flow = 6.25 (Ft/s)
Correction to map slope used on extremely rugged channels with
drops and waterfalls (Plate D-6.2)
Normal channel slope = 0.0439
Corrected/adjusted channel slope = 0.0439
Travel time = 0.96 min. TC = 11.74 min.
Adding area flow to channel
UNDEVELOPED (poor cover) subarea
Runoff Coefficient = 0.817
Decimal fraction soil group A = 0.000
Decimal fraction soil group B = 0.000
Decimal fraction soil group C = 1.000
Decimal fraction soil group D = 0.000
RI index for soil (AMC 2) = 86.00
Pervious area fraction = 1.000; Impervious fraction = 0.000
Rainfall intensity = 2 .144 (In/Hr) for a 10 .0 year storm
Subarea runoff = 4 .118 (CFS) for 2 .350 (Ac. )
Total runoff = 21.672 (CFS) Total area = 11.850 (Ac. )
)
27
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
Process from Point/Station 22 .000 to Point/Station 23 .000
**** IMPROVED CHANNEL TRAVEL TIME **** A4
Upstream point elevation = 1466.200 (Ft. )
Downstream point elevation = 1451.000 (Ft. )
Channel length thru subarea = 585 .000 (Ft. )
Channel base width = 0 .000 (Ft. )
Slope or 'Z' of left channel bank = 1.000
Slope or 'Z' of right channel bank = 1. 000
Estimated mean flow rate at midpoint of channel = 35.114 (CFS)
Manning's 'N' = 0.015
Maximum depth of channel = 3.000 (Ft. )
Flow(q) thru subarea = 35 . 114 (CFS)
Depth of flow = 1.743 (Ft. ) , Average velocity = 11.563 (Ft/s)
Channel flow top width = 3 .485 (Ft.)
Flow Velocity = 11.56 (Ft/s)
Travel time = 0.84 min.
Time of concentration = 12 .58 min.
Sub-Channel No. 1 Critical depth = 2 .375 (Ft. )
' Critical flow top width = 4.750 (Ft.)
' Critical flow velocity= 6.225 (Ft/s)
' I ' Critical flow area = 5.641 (Sq.Ft)
Adding area flow to channel
UNDEVELOPED (poor cover) subarea
Runoff Coefficient = 0.815
Decimal fraction soil group A = 0.000
Decimal fraction soil group B = 0.000
Decimal fraction soil group C = 1.000
Decimal fraction soil group D = 0.000
RI index for soil(AMC 2) = 86.00
Pervious area fraction = 1.000; Impervious fraction = 0.000
Rainfall intensity = 2 .074 (In/Hr) for a 10.0 year storm
Subarea runoff = 24.840 (CFS) for 14.700 (Ac. )
Total runoff = 46.512 (CFS) Total area = 26.550 (Ac. )
I
28
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
Process from Point/Station 23 .000 to Point/Station 24 . 000
**** IMPROVED CHANNEL TRAVEL TIME **** A5
Upstream point elevation = 1451.000 (Ft. )
Downstream point elevation = 1432.300 (Ft. )
Channel length thru subarea = 265.000 (Ft.)
Channel base width = 0.000 (Ft. )
Slope or 'Z' of left channel bank = 1. 000
Slope or 'Z' of right channel bank = 1.000
Estimated mean flow rate at midpoint of channel = 48.921 (CFS)
Manning's 'N' = 0.015
Maximum depth of channel = 2.000 (Ft. )
Flow(q) thru subarea = 48.921(CFS)
Depth of flow = 1.636 (Ft. ) , Average velocity = 18.271(Ft/s)
Channel flow top width = 3.273 (Ft. )
Flow Velocity = 18.27 (Ft/s)
Travel time = 0.24 min.
Time of concentration = 12 .83 min.
Sub-Channel No. 1 Critical depth = 2 .672 (Ft. )
' Critical flow top width = 4.000 (Ft. )
' ' I Critical flow velocity= 7.315 (Ft/s)
' ' Critical flow area = 6.688 (Sq.Ft)
Adding area flow to channel
UNDEVELOPED (poor cover) subarea
Runoff Coefficient = 0.814
Decimal fraction soil group A = 0.000
Decimal fraction soil group B = 0.000
Decimal fraction soil group C = 1.000
Decimal fraction soil group D = 0.000
RI index for soil (AMC 2) = 86.00
Pervious area fraction = 1.000; Impervious fraction = 0.000
Rainfall intensity = 2 .055 (In/Hr) for a 10.0 year storm
Subarea runoff = 4.601(CFS) for 2 .750 (Ac. )
Total runoff = 51.113 (CFS) Total area = 29.300 (Ac. )
Qlo = 51. 1 cfs Discharges to a low point
I
29
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
Process from Point/Station 3.000 to Point/Station 4 .000
**** INITIAL AREA EVALUATION **** B1
Initial area flow distance = 990.000 (Ft. )
Top (of initial area) elevation = 1761.000 (Ft. )
Bottom (of initial area) elevation = 1488 .700 (Ft. )
Difference in elevation = 272 .300 (Ft. )
Slope = 0.27505 s (percent) = 27.51
TC = M0.530) * [ (length'3) / (elevation change) ] '0.2
Initial area time of concentration = 10 .830 min.
Rainfall intensity = 2.229(In/Hr) for a 10.0 year storm
UNDEVELOPED (poor cover) subarea
Runoff Coefficient = 0.820
Decimal fraction soil group A = 0.000
Decimal fraction soil group B = 0.000
Decimal fraction soil group C = 1.000
Decimal fraction soil group D = 0.000
RI index for soil (AMC 2) = 86.00
Pervious area fraction = 1.000; Impervious fraction = 0.000
Initial subarea runoff = 10.786(CFS)
Total initial stream area = 5.900 (Ac. )
Pervious area fraction = 1.000
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
Process from Point/Station 4.000 to Point/Station 4.000
**** SUBAREA FLOW ADDITION **** B2
UNDEVELOPED (poor cover) subarea
Runoff Coefficient = 0. 820
Decimal fraction soil group A = 0.000
Decimal fraction soil group B = 0.000
Decimal fraction soil group C = 1.000
Decimal fraction soil group D = 0.000
RI index for soil (AMC 2) = 86.00
Pervious area fraction = 1.000; Impervious fraction = 0.000
Time of concentration = 10.83 min.
Rainfall intensity = 2.229 (In/Hr) for a 10.0 year storm
Subarea runoff = 9.415 (CFS) for 5.150 (Ac. )
Total runoff = 20i200 (CFS) Total area = 11.050 (Ac. )
I
30
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
Process from Point/Station 4 . 000 to Point/Station 5.000
**** IMPROVED CHANNEL TRAVEL TIME **** B3 + B4
Upstream point elevation = 1488.700 (Ft. )
Downstream point elevation = 1470.400 (Ft.)
Channel length thru subarea = 790. 000 (Ft. )
Channel base width = 0.000 (Ft. )
Slope or 'Z' of left channel bank = 1.000
Slope or 'Z' of right channel bank = 1.000
Estimated mean flow rate at midpoint of channel = 34.048 (CFS)
Manning's 'N' = 0.015
Maximum depth of channel = 3.000 (Ft.)
Flow(q) thru subarea = 34.048 (CFS)
Depth of flow = 1.760 (Ft. ) , Average velocity = 10.990 (Ft/s)
Channel flow top width = 3.520 (Ft: )
Flow Velocity = 10.99 (Ft/s)
Travel time = 1.20 min.
Time of concentration = 12 .03 min.
Sub-Channel No. 1 Critical depth = 2 .344 (Ft. )
' ' Critical flow top width = 4.688 (Ft. )
' ' Critical flow velocity= 6.198 (Ft/s)
' ' ' Critical flow area = 5 .493 (Sq.Ft)
Adding area flow to channel
UNDEVELOPED (poor cover) subarea
Runoff Coefficient = 0.816
Decimal fraction soil group A = 0.000
Decimal fraction soil group B = 0.000
Decimal fraction soil group C = 1.000
Decimal fraction soil group D = 0.000
RI index for soil (PMC 2) = 86.00
Pervious area fraction = 1.000; Impervious fraction = 0. 000
Rainfall intensity = 2 .120 (In/Hr) for a 10.0 year storm
Subarea runoff = 26.215 (CFS) for 15.150 (Ac. )
Total runoff = 46.415 (CFS) Total area = 26.200 (Ac.)
Qlo = 46 .4 cfs Discharges to a low point
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
Process from Point/Station 5 . 000 to Point/Station 5.100
**** PIPEFLOW TRAVEL TIME (Program estimated size) ****
Upstream point/station elevation = 1470.400 (Ft. )
Downstream point/station elevation = 1449.000 (Ft. )
Pipe length = 85. 00 (Ft. ) Manning' s N = 0.013
No. of pipes = 1 Required pipe flow = 46.415 (CFS)
Nearest computed pipe diameter = 18.00 (In. )
Calculated individual pipe flow = 46.415 (CFS)
Normal flow depth in pipe = 13 .10 (In. )
Flow top width inside pipe = 16.02 (In. )
Critical depth could not be calculated.
Pipe flow velocity = 33 .65 (Ft/s)
Travel time through pipe = 0.04 min.
Time of concentration (TC) = 12.07 min.
31
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
Process from Point/Station 5.100 to Point/Station 5.100
**** SUBAREA FLOW ADDITION **** B5
COMMERCIAL subarea type
Runoff Coefficient = 0.880
Decimal fraction soil group A = 0.000
Decimal fraction soil group B = 0.000
Decimal fraction soil group C = 1.000
Decimal fraction soil group D = 0.000
RI index for soil (AMC 2) = 69.00
Pervious area fraction = 0.100; Impervious fraction = 0.900
Time of concentration = 12.07 min.
Rainfall intensity = 2.116 (In/Hr) for a 10.0 year storm
Subarea runoff = 3 .445 (CFS) for 1.850 (Ac.)
Total runoff = 49.861(CFS) Total area = 28.050 (Ac. )
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
Process from Point/Station 5.100 to Point/Station 5.100
**** SUBAREA FLOW ADDITION**** B7
COMMERCIAL subarea type
Runoff Coefficient = 0.880
Decimal fraction soil group A = 0.000
Decimal fraction soil group B = 0.000
Decimal fraction soil group C = 1.000
Decimal fraction soil group D = 0.000
RI index for soil (AMC 2) = 69. 00
Pervious area fraction = 0.100; Impervious fraction = 0 :900
Time of concentration = 12 .07 min.
Rainfall intensity = 2.116 (In/Hr) for a 10.0 year storm
Subarea runoff = 1.955 (CFS) for 1.050 (Ac. )
Total runoff = 51. 816 (CFS) Total area = 29.100 (Ac. )
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
Process from Point/Station 5.100 to Point/Station 5.200
**** PIPEFLOW TRAVEL TIME (Program estimated size) ****
Upstream point/station elevation = 1449.000 (Ft.)
Downstream point/station elevation = 1447.000 (Ft. )
Pipe length = 100.00 (Ft. ) Manning' s N = 0.013
No. of pipes = 1 Required pipe flow = 51.816 (CFS)
Nearest computed pipe diameter = 30 .00 (In. )
Calculated individual pipe flow = 51.816(CFS)
Normal flow depth in pipe = 22 .13 (In. )
Flow top width inside pipe = 26.40 (In. )
Critical Depth = 27.87 (In. )
Pipe flow velocity = 13.36 (Ft/s)
Travel time through pipe = 0.12 min.
Time of concentration (TC) = 12.20 min.
32
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
Process from Point/Station 5.200 to Point/Station 5.200
**** SUBAREA FLOW ADDITION **** B6
COMMERCIAL subarea type
Runoff Coefficient = 0.880
Decimal fraction soil group A = 0.000
Decimal fraction soil group B = 0.000
Decimal fraction soil group C = 1.000
Decimal fraction soil group D = 0.000
RI index for soil (AMC 2) = 69.00
Pervious area fraction = 0.100; Impervious fraction = 0 .900
Time of concentration = 12.20 min.
Rainfall intensity = 2.106 (In/Hr) for a 10.0 year storm
Subarea runoff = 0.927 (CFS) for 0.500 (Ac.)
Total runoff = 52.743 (CFS) Total area = 29.600 (Ac.)
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
Process from Point/Station 5.200 to Point/Station 5.200
**** SUBAREA FLOW ADDITION **** B8
COMMERCIAL subarea type
Runoff Coefficient = 0.880
Decimal fraction soil group A = 0.000
Decimal fraction soil group B = 0.000
Decimal fraction soil group C = 1.000
Decimal fraction soil group D = 0.000
RI index for soil (AMC 2) = 69.00
Pervious area fraction = 0.100; Impervious fraction = 0 :900
Time of concentration = 12 .20 min.
Rainfall intensity = 2 .106 (In/Hr) for a 10.0 year storm
Subarea runoff = 0.649 (CFS) for 0.350 (Ac.)
Total runoff = 53 .391 (CFS) Total area = 29.950 (Ac.)
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
Process from Point/Station 5.200 to Point/Station 5.300
**** PIPEFLOW TRAVEL TIME (Program estimated size) ****
Upstream point/station elevation = 1447 .000 (Ft. )
Downstream point/station elevation = 1440.000 (Ft.)
Pipe length = 245.00 (Ft.) Manning's N = 0.013
No. of pipes = 1 Required pipe flow = 53.391 (CFS)
Nearest computed pipe diameter = 27. 00 (In. )
Calculated individual pipe flow = 53 .391 (CFS)
Normal flow depth in pipe = 22 .64 (In. )
Flow top width inside pipe = 19.87 (In. )
Critical depth could not be calculated.
Pipe flow velocity = 14.99 (Ft/s)
Travel time through pipe = 0.27 min.
Time of concentration (TC) = 12.47 min.
33
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
Process from Point/Station 5.300 to Point/Station 5.300
**** CONFLUENCE OF MINOR STREAMS ****
Along Main Stream number: 1 in normal stream number 1
Stream flow area = 29.950 (Ac.)
Runoff from this stream = 53 .391(CFS)
Time of concentration = 12 .47 min.
Rainfall intensity = 2 .083 (In/Hr)
Confluence with Subarea "E"
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
Process from Point/Station 10.000 to Point/Station 11.000
**** INITIAL AREA EVALUATION **** $
Initial area flow distance = 640.000 (Ft.)
Top (of initial area) elevation = 1515.000 (Ft. )
Bottom (of initial area) elevation = 1446.500 (Ft.)
Difference in elevation = 68.500(Ft.)
Slope = 0.10703 s (percent) = 10.70
TC = k(0.530) * [ (length^3) / (elevation change) ] '0.2
Initial area time of concentration = 10.986 min.
Rainfall intensity = 2 .214 (In/Hr) for a 10 .0 year storm
UNDEVELOPED (poor cover) subarea
Runoff Coefficient = 0.820
Decimal fraction soil group A = 0.000
Decimal fraction soil group B = 0.000
Decimal fraction soil group C = 1.000
Decimal fraction soil group D = 0.000
RI index for soil (AMC 2) = 86.00
Pervious area fraction = 1.000; Impervious fraction = 0.000
Initial subarea runoff = 4.990 (CFS)
Total initial stream area = 2.750 (Ac. )
Pervious area fraction = 1.000
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
Process from Point/Station 11.000 to Point/Station 5.300
**** PIPEFLOW TRAVEL TIME (Program estimated size) ****
Upstream point/station elevation = 1446.500 (Ft. )
Downstream point/station elevation = 1440.000 (Ft. )
Pipe length = 80.00 (Ft. ) Manning' s N = 0 .013
No. of pipes = 1 Required pipe flow = 4.990 (CFS)
Nearest computed pipe diameter = 12 .00 (In. )
Calculated individual pipe flow = 4 .990 (CFS)
Normal flow depth in pipe = 5.94 (In. )
Flow top width inside pipe = 12.00 (In. )
Critical Depth = 11.00 (In. )
Pipe flow velocity = 12 . 88 (Ft/s)
Travel time through pipe = 0.10 min.
Time of concentration (TC) = 11.09 min.
34
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
Process from Point/Station 5.300 to Point/Station 5.300
**** CONFLUENCE OF MINOR STREAMS ****
Along Main Stream number: 1 in normal stream number 2
Stream flow area = 2 .750 (Ac. )
Runoff from this stream = 4.990 (CFS)
Time of concentration = 11.09 min.
Rainfall intensity = 2 .204 (In/Hr)
Summary of stream data:
Stream Flow rate TC Rainfall Intensity
No. (CFS) (min) (In/Hr)
1 53 .391 12.47 2.083
2 4.990 11.09 2.204
Largest stream flow has longer time of concentration
Qp = 53.391 + sum of
Qb Ia/Ib
4.990 * 0.945 = 4.717
Qp = 58.108
Total of 2 streams to confluence:
Flow rates before confluence point:
53.391 4.990
Area of streams before confluence:
29.950 2.750
Results of confluence:
Total flow rate = 58 .108 (CFS)
Time of concentration = 12 .468 min.
Effective stream area after confluence = 32.700 (Ac. )
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
Process from Point/Station 5.300 to Point/Station 11.100
**** PIPEFLOW TRAVEL TIME (Program estimated size) ****
Upstream point/station elevation = 1440.000 (Ft. )
Downstream point/station elevation = 1420.000 (Ft. )
Pipe length = 80.00 (Ft. ) Manning's N = 0 .013
No. of pipes = 1 Required pipe flow = 58 .108 (CFS)
Nearest computed pipe diameter = 21.00 (In. )
Calculated individual pipe flow = 58.108 (CFS)
Normal flow depth in pipe = 13 .36 (In.)
Flow top width inside pipe = 20.21(In. )
Critical depth could not be calculated.
Pipe flow velocity = 35 .98 (Ft/s)
Travel time through pipe = 0.04 min.
Time of concentration (TC) = 12 .50 min.
Q10 = 58.1 cfs Discharges to Cottonwood Creek
35
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
Process from Point/Station 12.000 to Point/Station 12 .100
**** INITIAL AREA EVALUATION **** C
Initial area flow distance = 170.000 (Ft. )
Top (of initial area) elevation = 1500.000 (Ft. )
Bottom (of initial area) elevation = 1482 .900 (Ft. )
Difference in elevation = 17.100 (Ft. )
Slope = 0.10059 s (percent)= 10 .06
TC = k(0.530) * [ (length'3) / (elevation change) ] '0.2
Initial area time of concentration = 6.546 min.
Rainfall intensity = 2 .838 (In/Hr) for a 10. 0 year storm
UNDEVELOPED (poor cover) subarea
Runoff Coefficient = 0.836
Decimal fraction soil group A = 0.000
Decimal fraction soil group B = 0.000
Decimal fraction soil group C = 1.000
Decimal fraction soil group D = 0.000
RI index for soil (AMC 2) = 86.00
Pervious area fraction = 1.000; Impervious fraction = 0.000
Initial subarea runoff = 1.068 (CFS)
Total initial stream area = 0.450 (Ac.)
Pervious area fraction = 1.000
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
Process from Point/Station 12 .100 to Point/Station 12 .200
**** PIPEFLOW TRAVEL TIME (Program estimated size) ****
Upstream point/station elevation = 1482.900 (Ft. )
Downstream point/station elevation = 1460.000 (Ft.)
Pipe length = 190.00 (Ft. ) Manning's N = 0.013
No. of pipes = 1 Required pipe flow = 1.068 (CFS)
Nearest computed pipe diameter = 6.00 (In.)
Calculated individual pipe flow = 1.068 (CFS)
Normal flow depth in pipe = 3 .17 (In. )
Flow top width inside pipe = 5 .99 (In.)
Critical depth could not be calculated.
Pipe flow velocity = 10.15 (Ft/s)
Travel time through pipe = 0.31 min.
Time of concentration (TC) = 6.86 min.
Q10 = 1.1 cfs Discharges to Cottonwood Creek
36
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
Process from Point/Station 6.000 to Point/Station 7.000
**** INITIAL AREA EVALUATION **** DI
Initial area flow distance = 900.000 (Ft. )
Top (of initial area) elevation = 1741.000 (Ft. )
Bottom (of initial area) elevation = 1478.200 (Ft. )
Difference in elevation = 262 .800 (Ft. )
Slope = 0.29200 s (percent)= 29.20
TC = k(0.530) * ( (length'3) / (elevation change) ] "0.2
Initial area time of concentration = 10.301 min.
Rainfall intensity = 2.283 (In/Hr) for a 10.0 year storm
UNDEVELOPED (poor cover) subarea
Runoff Coefficient = 0 .822
Decimal fraction soil group A = 0.000
Decimal fraction soil group B = 0.000
Decimal fraction soil group C = 1.000
Decimal fraction soil group D = 0.000
RI index for soil (AMC 2) = 86.00
Pervious area fraction = 1.000; Impervious fraction 0.000
Initial subarea runoff = 12.103 (CFS)
Total initial stream area = 6.450 (Ac. )
Pervious area fraction = 1.000
Q10 = 12 . 1 cfs Enters project site @ project boundary
i
37
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
Process from Point/Station 7.000 to Point/Station 8.000
**** IMPROVED CHANNEL TRAVEL TIME **** D2
Upstream point elevation = 1478.200 (Ft. )
Downstream point elevation = 1448.500 (Ft.)
Channel length thru subarea = 660.000 (Ft. )
Channel base width = 0.000 (Ft.)
Slope or 'Z' of left channel bank = 1.000
Slope or 'Z' of right channel bank = 1.000
Estimated mean flow rate at midpoint of channel = 14.308 (CFS)
Manning's 'N' = 0.015
Maximum depth of channel = 2 .000 (Ft. )
Flow(q) thru subarea = 14.308 (CFS)
Depth of flow = 1. 123 (Ft.) , Average velocity = 11.351 (Ft/s)
Channel flow top width = 2.245 (Ft.)
Flow Velocity = 11.35 (Ft/s)
Travel time = 0.97 min.
Time of concentration = 11.27 min.
Sub-Channel No. 1 Critical depth = 1.664 (Ft.)
' Critical flow top width = 3 .328 (Ft. )
' ' Critical flow velocity= 5 .167 (Ft/s)
' Critical flow area = 2 .769 (Sq.Ft)
Adding area flow to channel
UNDEVELOPED (poor cover) subarea
Runoff Coefficient = 0.819
Decimal fraction soil group A = 0.000
Decimal fraction soil group B = 0.000
Decimal fraction soil group C = 1.000
Decimal fraction soil group D = 0.000
RI index for soil(AMC 2) = 86.00
Pervious area fraction = 1.000; Impervious fraction = 0 .000
Rainfall intensity = 2 .187 (In/Hr) for a 10.0 year storm
Subarea runoff = 4.207 (CFS) for 2 .350 (Ac. )
Total runoff = 16.311 (CFS) Total area = 8.800 (Ac.)
38
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
Process from Point/Station 8 .000 to Point/Station 9.000
**** IMPROVED CHANNEL TRAVEL TIME ****
Upstream point elevation = 1448 .500 (Ft.)
Downstream point elevation = 1440 .800 (Ft.)
Channel length thru subarea = 300. 000 (Ft.)
Channel base width = 0.000 (Ft. )
Slope or 'Z' of left channel bank = 1.000
Slope or 'Z' of right channel bank = 1.000
Estimated mean flow rate at midpoint of channel = 29.517 (CFS)
Manning's 'N' = 0.015
Maximum depth of channel = 2.000 (Ft.)
Flow(q) thru subarea = 29.517 (CFS)
Depth of flow = 1.637 (Ft.) , Average velocity = 11.021(Ft/s)
Channel flow top width = 3.273 (Ft. )
Flow Velocity = 11.02 (Ft/s)
Travel time = 0 .45 min.
Time of concentration = 11.72 min.
Sub-Channel No. 1 Critical depth = 2.188 (Ft. )
' Critical flow top width = 4.000 (Ft. )
' Critical flow velocity= 6.214 (Ft/s)
' ' Critical flow area = 4.750 (Sq.Ft)
Adding area flow to channel
UNDEVELOPED (poor cover) subarea
Runoff Coefficient = 0.817
Decimal fraction soil group A = 0. 000
Decimal fraction soil group B = 0.000
Decimal fraction soil group C = 1.000
Decimal fraction soil group D = 0. 000
RI index for soil (AMC 2) = 86.00
Pervious area fraction = 1.000; Impervious fraction = 0.000
Rainfall intensity = 2 .146 (In/Hr) for a 10.0 year storm
Subarea runoff = 24.991 (CFS) for 14.250 (Ac.)
Total runoff = 41.302 (CFS) Total area = 23.050 (Ac. )
410 = 41 .3 cfs Discharges to a low point
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
Process from Point/Station 9.000 to Point/Station 9.100
**** PIPEFLOW TRAVEL TIME (Program estimated size) ****
Upstream point/station elevation = 1440 .800 (Ft. )
Downstream point/station elevation = 1433 .700 (Ft. )
Pipe length = 40.00 (Ft.) Manning's N = 0. 013
No. of pipes = 1 Required pipe flow = 41.302 (CFS)
Nearest computed pipe diameter = 18 .00 (In. )
Calculated individual pipe flow = 41.302 (CFS)
Normal flow depth in pipe = 13 .78 (In. )
Flow top width inside pipe = 15 .25 (In. )
Critical depth could not be calculated.
Pipe flow velocity = 28.46 (Ft/s)
Travel time through pipe = 0.02 min.
Time of concentration (TC) = 11.75 min.
39
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
Process from Point/Station 9.100 to Point/Station 9.100
**** SUBAREA FLOW ADDITION **** D5
COMMERCIAL subarea type
Runoff Coefficient = 0.880
Decimal fraction soil group A = 0.000
Decimal fraction soil group B = 0 .000
Decimal fraction soil group C = 1.000
Decimal fraction soil group D = 0 .000
RI index for soil (AMC 2) = 69.00
Pervious area fraction = 0.100; Impervious fraction = 0.900
Time of concentration = 11.75 min.
Rainfall intensity = 2.144 (In/Hr) for a 10.0 year storm
Subarea runoff = 1.132 (CFS) for 0.600 (Ac.)
Total runoff = 42 .434 (CFS) Total area = 23 .650 (Ac.)
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
Process from Point/Station 9.100 to Point/Station 9.100
**** SUBAREA FLOW ADDITION **** D6
COMMERCIAL subarea type
Runoff Coefficient = 0.880
Decimal fraction soil group A = 0 .000
Decimal fraction soil group B = 0 .000
Decimal fraction soil group C = 1.000
Decimal fraction soil group D = 0 .000
RI index for soil (AMC 2) = 69.00
Pervious area fraction = 0.100; Impervious fraction = 0.900
Time of concentration = 11.75 min.
Rainfall intensity = 2 .144 (In/Hr) for a 10.0 year storm
Subarea runoff = 0.566 (CFS) for 0 .300 (Ac.)
Total runoff = 43 .001(CFS) Total area = 23 .950 (Ac.)
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
Process from Point/Station 9.100 to Point/Station 9.200
**** PIPEFLOW TRAVEL TIME (Program estimated size) ****
Upstream point/station elevation = 1433 .700 (Ft.)
Downstream point/station elevation = 1422 .900 (Ft. )
Pipe length = 95 .00 (Ft. ) Manning' s N = 0.013
No. of pipes = 1 Required pipe flow = 43 .001(CFS)
Nearest computed pipe diameter = 21.00 (In. )
Calculated individual pipe flow = 43 .001 (CFS)
Normal flow depth in pipe = 14.27 (In. )
Flow top width inside pipe = 19.60 (In. )
Critical depth could not be calculated.
Pipe flow velocity = 24.70 (Ft/s)
Travel time through pipe = 0.06 min.
Time of concentration (TC) = 11.81 min.
40
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
Process from Point/Station 9.200 to Point/Station 9.200
**** SUBAREA FLOW ADDITION **** D7
COMMERCIAL subarea type
Runoff Coefficient = 0 .880
Decimal fraction soil group A = 0. 000
Decimal fraction soil group B = 0. 000
Decimal fraction soil group C = 1. 000
Decimal fraction soil group D = 0. 000
RI index for soil (AMC 2) = 69.00
Pervious area fraction = 0.100; Impervious fraction = 0.900
Time of concentration = 11.81 min.
Rainfall intensity = 2.138 (In/Hr) for a 10.0 year storm
Subarea runoff = 1.129(CFS) for 0. 600 (Ac.)
Total runoff = 44.130 (CFS) Total area = 24.550 (Ac.)
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
Process from Point/Station 9.200 to Point/Station 9.200
**** SUBAREA FLOW ADDITION **** D8
COMMERCIAL subarea type
Runoff Coefficient = 0.880
Decimal fraction soil group A = 0.000
Decimal fraction soil group B = 0.000
Decimal fraction soil group C = 1.000
Decimal fraction soil group D = 0.000
RI index for soil (AMC 2) = 69.00
Pervious area fraction = 0.100; Impervious fraction = 0 .900
Time of concentration = 11.81 min.
Rainfall intensity = 2 .138 (In/Hr) for a 10.0 year storm
Subarea runoff = 0.565 (CFS) for 0.300 (Ac.)
Total runoff = 44.695 (CFS) Total area = 24.850 (Ac. )
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
Process from Point/Station 9.200 to Point/Station 9.300
**** PIPEFLOW TRAVEL TIME (Program estimated size) ****
Upstream point/station elevation = 1422 .900 (Ft.)
Downstream point/station elevation = 1422 .000 (Ft. )
Pipe length = 65.00 (Ft.) Manning's N = 0. 013
No. of pipes = 1 Required pipe flow = 44.695 (CFS)
Nearest computed pipe diameter = 30.00 (In. )
Calculated individual pipe flow = 44.695 (CFS)
Normal flow depth in pipe = 22 .80 (In.)
Flow top width inside pipe = 25.62 (In.)
Critical Depth = 26.65 (In.)
Pipe flow velocity = 11.16 (Ft/s)
Travel time through pipe = 0.10 min.
Time of concentration (TC) = 11.91 min.
Q10 = 44 .7 cfs Discharges to Cottonwood Creek
41
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
Process from Point/Station 25 .000 to Point/Station 26.000
**** INITIAL AREA EVALUATION **** F1
Initial area flow distance = 795 .000 (Ft. )
Top (of initial area) elevation = 1701.000 (Ft. )
Bottom (of initial area) elevation = 1446.000 (Ft. )
Difference in elevation = 255.000 (Ft.)
Slope = 0.32075 s (percent) = 32 .08
TC = k(0.530) * [ (length'3) / (elevation change) ] ^0.2
Initial area time of concentration = 9.620 min.
Rainfall intensity = 2.359 (In/Hr) for a 10.0 year storm
UNDEVELOPED (poor cover) subarea
Runoff Coefficient = 0.824
Decimal fraction soil group A = 0.000
Decimal fraction soil group B = 0. 000
Decimal fraction soil group C = 1. 000
Decimal fraction soil group D = 0 . 000
RI index for soil (AMC 2) = 86.00
Pervious area fraction = 1.000; Impervious fraction = 0. 000
Initial subarea runoff = 6. 903 (CFS)
Total initial stream area = 3 .550 (Ac.)
Pervious area fraction = 1.000
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
Process from Point/Station 26.000 to Point/Station 27.000
**** IMPROVED CHANNEL TRAVEL TIME **** F2
Upstream point elevation = 1446.000 (Ft. )
Downstream point elevation = 1438 .000 (Ft.)
Channel length thru subarea = 20. 000 (Ft. )
Channel base width = 0.000 (Ft. )
Slope or 'Z' of left channel bank = 1.000
Slope or 'Z' of right channel bank = 1.000
Manning' s 'N' = 0 .015
Maximum depth of channel = 2.000 (Ft.)
Flow(q) thru subarea = 6.903 (CFS)
Depth of flow = 0 .567 (Ft.) , Average velocity = 21.464 (Ft/s)
Channel flow top width = 1.134 (Ft. )
Flow Velocity = 21.46 (Ft/s)
Travel time = 0 .02 min.
Time of concentration = 9.64 min.
Sub-Channel No. 1 Critical depth = 1.242 (Ft. )
Critical flow top width = 2 .464 (Ft. )
Critical flow velocity= 4 .474 (Ft/s)
Critical flow area = 1.543 (Sq.Ft)
1
42
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
Process from Point/Station 27 .000 to Point/Station 27.000
**** SUBAREA FLOW ADDITION **** F2
UNDEVELOPED (poor cover) subarea
Runoff Coefficient = 0 .824
Decimal fraction soil group A = 0 . 000
Decimal fraction soil group B = 0 .000
Decimal fraction soil group C = 1.000
Decimal fraction soil group D = 0 .000
RI index for soil(AMC 2) = 86.00
Pervious area fraction = 1.000; Impervious fraction = 0.000
Time of concentration = 9.64 min.
Rainfall intensity = 2.358 (In/Hr) for a 10.0 year storm
Subarea runoff = 0.291(CFS) for 0.150 (Ac.)
Total runoff = 7.195 (CFS) Total area = 3 .700 (Ac.)
410 = 7 .2 cfs Discharges to a low point
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
Process from Point/Station 30 .000 to Point/Station 31.000
**** INITIAL AREA EVALUATION **** G1
Initial area flow distance = 975.000 (Ft. )
Top (of initial area) elevation = 1633 .600 (Ft. )
Bottom (of initial area) elevation = 1425.000 (Ft.)
Difference in elevation = 208.600 (Ft.)
Slope = 0.21395 s (percent) = 21.39
TC = k(0.530) * [ (length"3) / (elevation change) ] '0 .2
Initial area time of concentration = 11.319 min.
Rainfall intensity = 2.182 (In/Hr) for a 10.0 year storm
UNDEVELOPED (poor cover) subarea
Runoff Coefficient = 0.819
Decimal fraction soil group A = 0 . 000
Decimal fraction soil group B = 0 .000
Decimal fraction soil group C = 1.000
Decimal fraction soil group D = 0 . 000
RI index for soil (AMC 2) = 86. 00
Pervious area fraction = 1.000; Impervious fraction = 0 .000
Initial subarea runoff = 10.986 (CFS)
Total initial stream area = 6.150 (Ac.)
Pervious area fraction = 1.000
I
43
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
Process from Point/Station 31.000 to Point/Station 32.000
**** NATURAL CHANNEL TIME + SUBAREA FLOW ADDITION **** G2
Top of natural channel elevation = 1425.000 (Ft. )
End of natural channel elevation = 1392.000 (Ft. )
Length of natural channel = 545.000 (Ft. )
Estimated mean flow rate at midpoint of channel = 18.400 (CFS)
Natural valley channel type used
L.A. County flood control district formula for channel velocity:
Velocity(ft/s) _ (7 + 8 (q(English Units) ".352) (slope^0.5)
Velocity using mean channel flow = 7.21 (Ft/s)
Correction to map slope used on extremely rugged channels with
drops and waterfalls (Plate D-6.2)
Normal channel slope = 0.0606
Corrected/adjusted channel slope = 0.0606
Travel time = 1.26 min. TC = 12 .58 min.
Adding area flow to channel
UNDEVELOPED (poor cover) subarea
Runoff Coefficient = 0.815
Decimal fraction soil group A = 0. 000
Decimal fraction soil group B = 0.000
Decimal fraction soil group C = 1. 000
Decimal fraction soil group D = 0 . 000
RI index for soil (AMC 2) = 86.00
1 Pervious area fraction = 1.000; Impervious fraction = 0 .000
Rainfall intensity = 2.074 (In/Hr) for a 10.0 year storm
Subarea runoff = 14.028 (CFS) for 8.300 (Ac. )
Total runoff = 25.015 (CFS) Total area = 14.450 (Ac. )
1
44
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
Process from Point/Station 32.000 to Point/Station 33 .000
**** NATURAL CHANNEL TIME + SUBAREA FLOW ADDITION **** G3
Top of natural channel elevation = 1392 .000 (Ft. )
End of natural channel elevation = 1390.000 (Ft. )
Length of natural channel = 50.000 (Ft.)
Estimated mean flow rate at midpoint of channel = 30.771(CFS)
Natural valley channel type used
L.A. County flood control district formula for channel velocity:
Velocity(ft/s) _ (7 + 8 (q(English Units) ~.352) (slope"0.5)
Velocity using mean channel flow = 6.74 (Ft/s)
Correction to map slope used on extremely rugged channels with
drops and waterfalls (Plate D-6.2)
Normal channel slope = 0.0400
Corrected/adjusted channel slope = 0.0400
Travel time = 0.12 min. TC = 12.70 min.
Adding area flow to channel
UNDEVELOPED (poor cover) subarea
Runoff Coefficient = 0.814
Decimal fraction soil group A = 0.000
Decimal fraction soil group B = 0.000
Decimal fraction soil group C = 1.000
Decimal fraction soil group D = 0.000
RI index for soil (AMC 2) = 86.00
Pervious area fraction = 1.000; Impervious fraction = 0.000
Rainfall intensity = 2 .065 (In/Hr) for a 10 .0 year storm
Subarea runoff = 11.182 (CFS) for 6.650 (Ac. )
Total runoff = 36.197 (CFS) Total area = 21.100 (Ac.)
45
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
Process from Point/Station 33 .000 to Point/Station 34.000
**** NATURAL CHANNEL TIME + SUBAREA FLOW ADDITION **** G4
Top of natural channel elevation = 1390.000 (Ft. )
End of natural channel elevation = 1365.000 (Ft. )
Length of natural channel = 455. 000 (Ft.)
Estimated mean flow rate at midpoint of channel = 40 .014 (CFS)
Natural valley channel type used
L.A. County flood control district formula for channel velocity:
Velocity(ft/s) _ (7 + 8 (q(English Units) '.352) (slope^0.5)
Velocity using mean channel flow = 8.51(Ft/s)
Correction to map slope used on extremely rugged channels with
drops and waterfalls (Plate D-6.2)
Normal channel slope = 0.0549
Corrected/adjusted channel slope = 0.0549
Travel time = 0.89 min. TC = 13 .59 min.
Adding area flow to channel
UNDEVELOPED (poor cover) subarea
Runoff Coefficient = 0.812
Decimal fraction soil group A = 0.000
Decimal fraction soil group B = 0.000
Decimal fraction soil group C = 1.000
Decimal fraction soil group D = 0.000
RI index for soil (AMC 2) = 86.00
Pervious area fraction = 1.000; Impervious fraction = 0.000
Rainfall intensity = 1.999 (In/Hr) for a 10.0 year storm
Subarea runoff = 7.221 (CFS) for 4.450 (Ac. )
Total runoff = 43 .417 (CFS) Total area = 25.550 (Ac.)
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
Process from Point/Station 34.000 to Point/Station 34.000
**** SUBAREA FLOW ADDITION **** G5
UNDEVELOPED (poor cover) subarea
Runoff Coefficient = 0.812
Decimal fraction soil group A = 0. 000
Decimal fraction soil group B = 0.000
Decimal fraction soil group C = 1.000
Decimal fraction soil group D = 0.000
RI index for soil (AMC 2) = 86.00
Pervious area fraction = 1.000; Impervious fraction = 0.000
Time of concentration = 13 .59 min.
Rainfall intensity = 1.999 (In/Hr) for a 10.0 year storm
Subarea runoff = 17.199 (CFS) for 10.600 (Ac. )
Total runoff = 60 .617 (CFS) Total area = 36.150 (Ac.)
46
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
Process from Point/Station 34.000 to Point/Station 35.000
**** NATURAL CHANNEL TIME + SUBAREA FLOW ADDITION **** G6
Top of natural channel elevation = 1365 . 000 (Ft.)
End of natural channel elevation = 1304 . 000 (Ft.)
Length of natural channel = 925.000 (Ft. )
Estimated mean flow rate at midpoint of channel = 70 .468 (CFS)
Natural valley channel type used
L.A. County flood control district formula for channel velocity:
Velocity(ft/s) = (7 + 8 (q(English Units) ".352) (slope'0 .5)
Velocity using mean channel flow = 10.98 (Ft/s)
Correction to map slope used on extremely rugged channels with
drops and waterfalls (Plate D-6.2)
Normal channel slope = 0.0659
Corrected/adjusted channel slope = 0.0659
Travel time = 1.40 min. TC = 15. 00 min.
Adding area flow to channel
UNDEVELOPED (poor cover) subarea
Runoff Coefficient = 0.808
Decimal fraction soil group A = 0.000
Decimal fraction soil group B = 0.000
Decimal fraction soil group C = 1.000
Decimal fraction soil group D = 0.000
RI index for soil (AMC 2) = 86.00
Pervious area fraction = 1.000; Impervious fraction = 0.000
Rainfall intensity = 1.907 (In/Hr) for a 10.0 year storm
Subarea runoff = 18.101 (CFS) for 11.750 (Ac.)
Total runoff = 78.718 (CFS) Total area = 47.900 (Ac• )
4io = 78 .7 cfs Discharges to San Jacinto River
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
Process from Point/Station 36.000 to Point/Station 37.000
**** INITIAL AREA EVALUATION **** H1
Initial area flow distance = 835.000 (Ft. )
Top (of initial area) elevation = 1615 .000 (Ft. )
Bottom (of initial area) elevation = 1447 .700 (Ft.)
Difference in elevation = 167.300 (Ft. )
Slope = 0.20036 s (percent) = 20 .04
TC = k(0.530) * [ (length"3) / (elevation change) ] A0.2
Initial area time of concentration = 10.779 min.
Rainfall intensity = 2 .234 (In/Hr) for a 10.0 year storm
UNDEVELOPED (poor cover) subarea
Runoff Coefficient = 0.820
Decimal fraction soil group A = 0.000
Decimal fraction soil group B = 0.000
Decimal fraction soil group C = 1.000
Decimal fraction soil group D = 0.000
RI index for soil (AMC 2) = 86.00
Pervious area fraction = 1.000; Impervious fraction = 0 .000
Initial subarea runoff = 8.155 (CFS)
Total initial stream area = 4.450 (Ac. )
Pervious area fraction = 1.000
47
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
Process from Point/Station 37.000 to Point/Station 38.000
**** NATURAL CHANNEL TIME + SUBAREA FLOW ADDITION **** H2
Top of natural channel elevation = 1447.700 (Ft.)
End of natural channel elevation = 1428 .700 (Ft. )
Length of natural channel = 240.000 (Ft. )
Estimated mean flow rate at midpoint of channel = 15.806 (CFS)
Natural valley channel type used
L.A. County flood control district formula for channel velocity:
Velocity(ft/s) = (7 + 8 (q(English Units) '.352) (slope^0.5)
Velocity using mean channel flow = 7 .92 (Ft/s)
Correction to map slope used on extremely rugged channels with
drops and waterfalls (Plate D-6.2)
Normal channel slope = 0.0792
Corrected/adjusted channel slope = 0.0792
Travel time = 0.51 min. TC = 11.28 min.
Adding area flow to channel
UNDEVELOPED (poor cover) subarea
Runoff Coefficient = 0.819
Decimal fraction soil group A = 0.000
Decimal fraction soil group B = 0.000
Decimal fraction soil group C = 1.000
Decimal fraction soil group D = 0. 000
RI index for soil (AMC 2) = 86.00
} Pervious area fraction = 1.000; Impervious fraction = 0.000
Rainfall intensity = 2 .185 (In/Hr) for a 10. 0 year storm
Subarea runoff = 14 .940 (CFS) for 8.350 (Ac. )
Total runoff = 23.095 (CFS) Total area = 12.800 (Ac.)
48
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
Process from Point/Station 38.000 to Point/Station 39.000
**** NATURAL CHANNEL TIME + SUBAREA FLOW ADDITION **** H3
Top of natural channel elevation = 1428 .700 (Ft. )
End of natural channel elevation = 1405.000 (Ft. )
Length of natural channel = 290.000 (Ft. )
Estimated mean flow rate at midpoint of channel = 29.636 (CFS)
Natural valley channel type used
L.A. County flood control district formula for channel velocity:
Velocity(ft/s) = (7 + 8 (q(English Units) '.352) (slope'0.5)
Velocity using mean channel flow = 9.54 (Ft/s)
Correction to map slope used on extremely rugged channels with
drops and waterfalls (Plate D-6.2)
Normal channel slope = 0.0817
Corrected/adjusted channel slope = 0.0817
Travel time = 0.51 min. TC = 11.79 min.
Adding area flow to channel
UNDEVELOPED (poor cover) subarea
Runoff Coefficient = 0 . 817
Decimal fraction soil group A = 0 .000
Decimal fraction soil group B = 0 .000
Decimal fraction soil group C = 1.000
Decimal fraction soil group D = 0.000
RI index for soil (AMC 2) = 86.00
Pervious area fraction = 1.000; Impervious fraction = 0 .000
Rainfall intensity = 2.140 (In/Hr) for a 10.0 year storm
Subarea runoff = 12 .677 (CFS) for 7.250 (Ac.)
Total runoff = 35.772 (CFS) Total area = 20.050 (Ac.)
49
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
Process from Point/Station 39.000 to Point/Station 40.000
**** NATURAL CHANNEL TIME + SUBAREA FLOW ADDITION **** H4
Top of natural channel elevation = 1405.000 (Ft. )
End of natural channel elevation = 1325.000 (Ft. )
Length of natural channel = 760.000 (Ft.)
Estimated mean flow rate at midpoint of channel = 43 .444 (CFS)
Natural mountain channel type used
L.A. County flood control district formula for channel velocity:
Velocity = 5.48 (q'.33) (slopeA.492)
Velocity using mean channel flow = 6.24 (Ft/s)
Correction to map slope used on extremely rugged channels with
drops and waterfalls (Plate D-6.2)
Normal channel slope = 0 .1053
Corrected/adjusted channel slope = 0.1037
Travel time = 2.03 min. TC = 13 .82 min.
Adding area flow to channel
UNDEVELOPED (poor cover) subarea
Runoff Coefficient = 0 .811
Decimal fraction soil group A = 0 . 000
Decimal fraction soil group B = 0. 000
Decimal fraction soil group C = 1.000
Decimal fraction soil group D = 0 .000
RI index for soil(AMC 2) = 86.00
Pervious area fraction = 1.000; Impervious fraction = 0. 000
Rainfall intensity = 1.983 (In/Hr) for a 10.0 year storm
Subarea runoff = 13 .832 (CFS) for 8.600 (Ac.)
Total runoff = 49.604 (CFS) Total area = 28.650 (Ac.)
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
Process from Point/Station 40.000 to Point/Station 40.000
**** SUBAREA FLOW ADDITION **** H5
UNDEVELOPED (poor cover) subarea
Runoff Coefficient = 0. 811
Decimal fraction soil group A = 0. 000
Decimal fraction soil group B = 0 . 000
Decimal fraction soil group C = 1. 000
Decimal fraction soil group D = 0 . 000
RI index for soil (AMC 2) = 86. 00
Pervious area fraction = 1.000; Impervious fraction = 0. 000
Time of concentration = 13.82 min.
Rainfall intensity = 1.983 (In/Hr) for a 10.0 year storm
Subarea runoff = 10.374 (CFS) for 6.450 (Ac. )
Total runoff = 59.979 (CFS) Total area = 35 .100 (Ac.)
1
50
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
Process from Point/Station 40.000 to Point/Station 41.000
**** NATURAL CHANNEL TIME + SUBAREA FLOW ADDITION **** H6
Top of natural channel elevation = 1325.000 (Ft. )
End of natural channel elevation = 1310.000 (Ft. )
Length of natural channel = 205.000 (Ft. )
Estimated mean flow rate at midpoint of channel = 63 .524 (CFS)
Natural valley channel type used
L.A. County flood control district formula for channel velocity:
Velocity(ft/s) _ (7 + 8 (q(English Units) ^.352) (slope'0.5)
Velocity using mean channel flow = 11.22 (Ft/s)
Correction to map slope used on extremely rugged channels with
drops and waterfalls (Plate D-6.2)
Normal channel slope = 0 .0732
Corrected/adjusted channel slope = 0.0732
Travel time = 0.30 min. TC = 14.13 min.
Adding area flow to channel
UNDEVELOPED (poor cover) subarea
Runoff Coefficient = 0.810
Decimal fraction soil group A = 0 .000
Decimal fraction soil group B = 0.000
Decimal fraction soil group C = 1.000
Decimal fraction soil group D = 0.000
RI index for soil(AMC 2) = 86.00
Pervious area fraction = 1.000; Impervious fraction = 0.000
Rainfall intensity = 1.962 (In/Hr) for a 10.0 year storm
Subarea runoff = 6.599(CFS) for 4.150 (Ac.)
Total runoff = 66.577 (CFS) Total area = 39.250 (Ac.)
Qlo = 66 . 6 cfs Discharges to San Jacinto River
51
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
Process from Point/Station 1.000 to Point/Station 2.000
**** INITIAL AREA EVALUATION **** B3
Initial area flow distance = 700.000 (Ft. )
Top (of initial area) elevation = 1607 .100 (Ft. )
Bottom (of initial area) elevation = 1494.600 (Ft. )
Difference in elevation = 112.500 (Ft. )
Slope = 0.16071 s (percent)= 16.07
TC = k(0.530) * [ (length"3) / (elevation change) ] ^0.2
Initial area time of concentration = 10.498 min.
Rainfall intensity = 2 .263 (In/Hr) for a 10.0 year storm
UNDEVELOPED (poor cover) subarea
Runoff Coefficient = 0.821
Decimal fraction soil group A = 0.000
Decimal fraction soil group B = 0.000
Decimal fraction soil group C = 1.000
Decimal fraction soil group D = 0.000
RI index for soil (AMC 2) = 86.00
Pervious area fraction = 1.000; Impervious fraction = 0 .000
Initial subarea runoff = 6.875 (CFS)
Total initial stream area = 3 .700 (Ac.)
Pervious area fraction = 1.000
Q10 = 6 . 9 c f s Enters project site @ project boundary
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
Process from Point/Station 6.000 to Point/Station 6.100
**** INITIAL AREA EVALUATION **** D3
Initial area flow distance = 865.000 (Ft. )
Top (of initial area) elevation = 1741.000 (Ft. )
Bottom (of initial area) elevation = 1480.000 (Ft. )
Difference in elevation = 261.000 (Ft.)
Slope = 0 .30173 s (percent) = 30.17
TC = k(0.530) * [ (length^3) / (elevation change) ] '0.2
Initial area time of concentration = 10.073 min.
Rainfall intensity = 2 .308 (In/Hr) for a 10 .0 year storm
UNDEVELOPED (poor cover) subarea
Runoff Coefficient = 0.823
Decimal fraction soil group A = 0.000
Decimal fraction soil group B = 0.000
Decimal fraction soil group C = 1.000
Decimal fraction soil group D = 0.000
RI index for soil (AMC 2) = 86.00
Pervious area fraction = 1.000; Impervious fraction = 0.000
Initial subarea runoff = 9.493 (CFS)
Total initial stream area = 5.000 (Ac.)
Pervious area fraction = 1.000
Q3.0 = 9 .5 cfs Enters project site @ project boundary
}
52
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
Process from Point/Station 42 .100 to Point/Station 42.200
**** INITIAL AREA EVALUATION **** Il
Initial area flow distance = 615.000 (Ft.)
Top (of initial area) elevation = 1655.000 (Ft. )
Bottom (of initial area) elevation = 1524.000 (Ft. )
Difference in elevation = 131. 000 (Ft. )
Slope = 0 .21301 s (percent) = 21.30
TC = k(0 .530) * L (length'3) / (elevation change) ] '0.2
Initial area time of concentration = 9.422 min.
Rainfall intensity = 2 .383 (In/Hr) for a 10.0 year storm
UNDEVELOPED (poor cover) subarea
Runoff Coefficient = 0.825
Decimal fraction soil group A = 0 .000
Decimal fraction soil group B = 0.000
Decimal fraction soil group C = 1.000
Decimal fraction soil group D = 0.000
RI index for soil (AMC 2) = 86.00
Pervious area fraction = 1.000; Impervious fraction = 0.000
Initial subarea runoff = 8. 846 (CFS)
Total initial stream area = 4.500 (Ac.)
Pervious area fraction = 1.000
Q10 = 8 . 8 cfs Enters project site @ project boundary
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
Process from Point/Station 42 .200 to Point/Station 42.300
**** NATURAL CHANNEL TIME + SUBAREA FLOW ADDITION **** I2
Top of natural channel elevation = 1524.000 (Ft. )
End of natural channel elevation = 1494.000 (Ft. )
Length of natural channel = 515.000 (Ft.)
Estimated mean flow rate at midpoint of channel = 15.481 (CFS)
Natural valley channel type used
L.A. County flood control district formula for channel velocity:
Velocity(ft/s) = (7 + 8 (q(English Units) A.352) (slope"0.5)
Velocity using mean channel flow = 6.75 (Ft/s)
Correction to map slope used on extremely rugged channels with
drops and waterfalls (Plate D-6.2)
Normal channel slope = 0. 0583
Corrected/adjusted channel slope = 0 .0583
Travel time = 1.27 min. TC = 10.69 min.
Adding area flow to channel
UNDEVELOPED (poor cover) subarea
Runoff Coefficient = 0.821
Decimal fraction soil group A = 0.000
Decimal fraction soil group B = 0.000
Decimal fraction soil group C = 1.000
Decimal fraction soil group D = 0.000
RI index for soil (AMC 2) = 86.00
Pervious area fraction = 1.000; Impervious fraction = 0.000
Rainfall intensity = 2 .243 (In/Hr) for a 10. 0 year storm
Subarea runoff = 12 .422 (CFS) for 6.750 (Ac. )
Total runoff = 21.268 (CFS) Total area = 11.250 (Ac.)
53
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
Process from Point/Station 42 .300 to Point/Station 42 .400
**** NATURAL CHANNEL TIME + SUBAREA FLOW ADDITION **** I3
Top of natural channel elevation = 1494.000 (Ft.)
End of natural channel elevation = 1330.000 (Ft.)
Length of natural channel = 800.000 (Ft.)
Estimated mean flow rate at midpoint of channel = 25.522 (CFS)
Natural mountain channel type used
L.A. County flood control district formula for channel velocity:
Velocity = 5.48 (gA.33) (slopeA .492)
Velocity using mean channel flow = 6.52 (Ft/s)
Correction to map slope used on extremely rugged channels with
drops and waterfalls (Plate D-6.2)
Normal channel slope = 0 .2050
Corrected/adjusted channel slope = 0.1620
Travel time = 2 .05 min. TC = 12 .74 min.
Adding area flow to channel
UNDEVELOPED (poor cover) subarea
Runoff Coefficient = 0.814
Decimal fraction soil group A = 0 .000
Decimal fraction soil group B = 0 .000
Decimal fraction soil group C = 1.000
Decimal fraction soil group D = 0 .000
RI index for soil (AMC 2) = 86.00
Pervious area fraction = 1. 000; Impervious fraction = 0.000
Rainfall intensity = 2.062 (In/Hr) for a 10.0 year storm
Subarea runoff = 7.556 (CFS) for 4.500 (Ac. )
Total runoff = 28.824 (CFS) Total area = 15.750 (Ac.)
Q10 = 28 . 8 cfs Discharges to San Jacinto River
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
Process from Point/Station 43.100 to Point/Station 43.200
**** INITIAL AREA EVALUATION **** J
Initial area flow distance = 930.000 (Ft. )
Top (of initial area) elevation = 1550.000 (Ft. )
Bottom (of initial area) elevation = 1330.000 (Ft.)
Difference in elevation = 220 . 000 (Ft. )
Slope = 0.23656 s (percent) = 23 .66
TC = k(0.530) * [ (length'3) / (elevation change) ] A0.2
Initial area time of concentration = 10 . 886 min.
Rainfall intensity = 2.223 (In/Hr) for a 10.0 year storm
UNDEVELOPED (poor cover) subarea
Runoff Coefficient = 0.820
Decimal fraction soil group A = 0.000
Decimal fraction soil group B = 0 .000
Decimal fraction soil group C = 1.000
Decimal fraction soil group D = 0 .000
RI index for soil (AMC 2) = 86.00
Pervious area fraction = 1. 000; Impervious fraction = 0 .000
Initial subarea runoff = 6.655 (CFS)
Total initial stream area = 3.650 (Ac.)
Pervious area fraction = 1.000
} Qlo = 6 .7 cfs Discharges to San Jacinto River
54
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
Process from Point/Station 44.100 to Point/Station 44 .200
**** INITIAL AREA EVALUATION **** R1
Initial area flow distance = 870 .000 (Ft. )
Top (of initial area) elevation = 1655.000 (Ft.)
Bottom (of initial area) elevation = 1420 . 000 (Ft. )
Difference in elevation = 235 .000 (Ft. )
Slope = 0.27011 s (percent) = 27.01
TC = k(0.530) * [ (length'3) / (elevation change) ] '0.2
Initial area time of concentration = 10 .322 min.
Rainfall intensity = 2.281 (In/Hr) for a 10.0 year storm
UNDEVELOPED (poor cover) subarea
Runoff Coefficient = 0.822
Decimal fraction soil group A = 0.000
Decimal fraction soil group B = 0.000
Decimal fraction soil group C = 1.000
Decimal fraction soil group D = 0.000
RI index for soil (AMC 2) = 86.00
Pervious area fraction = 1.000; Impervious fraction = 0 .000
Initial subarea runoff = 6.842 (CFS)
Total initial stream area = 3.650 (Ac. )
Pervious area fraction = 1.000
41.0 = 6 . 8 cfs Discharges to San Jacinto River
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
Process from Point/Station 44.200 to Point/Station 44.300
**** NATURAL CHANNEL TIME + SUBAREA FLOW ADDITION **** K2
Top of natural channel elevation = 1420 .000 (Ft.)
End of natural channel elevation = 1330 .000 (Ft.)
Length of natural channel = 420.000 (Ft. )
Estimated mean flow rate at midpoint of channel = 10.732 (CFS)
Natural mountain channel type used
L.A. County flood control district formula for channel velocity:
Velocity = 5.48 (gA.33) (slopeA.492)
Velocity using mean channel flow = 4.95 (Ft/s)
Correction to map slope used on extremely rugged channels with
drops and waterfalls (Plate D-6.2)
Normal channel slope = 0.2143
Corrected/adjusted channel slope = 0.1657
Travel time = 1.41 min. TC = 11.74 min.
Adding area flow to channel
UNDEVELOPED (poor cover) subarea
Runoff Coefficient = 0.817
Decimal fraction soil group A = 0.000
Decimal fraction soil group B = 0.000
Decimal fraction soil group C = 1.000
Decimal fraction soil group D = 0.000
RI index for soil (AMC 2) = 86.00
Pervious area fraction = 1.000; Impervious fraction = 0.000
Rainfall intensity = 2 .145 (In/Hr) for a 10.0 year storm
Subarea runoff = 7.274 (CFS) for 4.150 (Ac.)
Total runoff = 14.116 (CFS) Total area = 7. 800 (Ac.)
1 Q10 = 14. 1 cfs Discharges to San Jacinto River
55
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
Process from Point/Station 44.100 to Point/Station 45.000
**** INITIAL AREA EVALUATION **** Ll
Initial area flow distance = 980.000 (Ft. )
Top (of initial area) elevation = 1655 .000 (Ft.)
Bottom (of initial area) elevation = 1400.000 (Ft. )
Difference in elevation = 255.000 (Ft. )
Slope = 0.26020 s (percent) = 26.02
TC = k(0.530) * [ (length^3) / (elevation change) ] '0.2
Initial area time of concentration = 10.907 min.
Rainfall intensity = 2 .221 (In/Hr) for a 10 .0 year storm
UNDEVELOPED (poor cover) subarea
Runoff Coefficient = 0.820
Decimal fraction soil group A = 0.000
Decimal fraction soil group B = 0.000
Decimal fraction soil group C = 1.000
Decimal fraction soil group D = 0.000
RI index for soil (AMC 2) = 86.00
Pervious area fraction = 1.000; Impervious fraction = 0.000
Initial subarea runoff = 10.382 (CFS)
Total initial stream area = 5.700 (Ac.)
Pervious area fraction = 1.000
410 = 10 .4 cfs Enters project site @ project boundary
i
56
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
Process from Point/Station 45.000 to Point/Station 45.100
**** NATURAL CHANNEL TIME + SUBAREA FLOW ADDITION **** L2
Top of natural channel elevation = 1400.000 (Ft. )
End of natural channel elevation = 1330.000 (Ft. )
Length of natural channel = 285.000 (Ft.)
Estimated mean flow rate at midpoint of channel = 12 .750 (CFS)
Natural mountain channel type used
L.A. County flood control district formula for channel velocity:
Velocity = 5.48 (gA.33) (slopeA.492)
Velocity using mean channel flow = 5.43 (Ft/s)
Correction to map slope used on extremely rugged channels with
drops and waterfalls (Plate D-6.2)
Normal channel slope = 0.2456
Corrected/adjusted channel slope = 0.1782
Travel time = 0.87 min. TC = 11.76 min.
Adding area flow to channel
UNDEVELOPED (poor cover) subarea
Runoff Coefficient = 0.817
Decimal fraction soil group A = 0.000
Decimal fraction soil group B = 0 .000
Decimal fraction soil group C = 1.000
Decimal fraction soil group D = 0 .000
RI index for soil (AMC 2) = 86. 00
Pervious area fraction = 1.000; Impervious fraction = 0 . 000
Rainfall intensity = 2 .141 (In/Hr) for a 10.0 year storm
Subarea runoff = 4.548 (CFS) for 2 .600 (Ac.)
Total runoff = 14.930 (CFS) Total area = 8.300 (Ac. )
End of computations, total study area = 222.35 (Ac. )
The following figures may
be used for a unit hydrograph study of the same area.
Area averaged pervious area fraction(Ap) = 0.978
Area averaged RI index number = 85 .6
410 = 14 . 9 cfs Discharges to San Jacinto River
100 YEAR STORM
58
Riverside County Rational Hydrology Program
CIVILCADD/CIVILDESIGN Engineering Software, (c) 1989 - 1997 Version 5.0
Rational Hydrology Study Date: 05/22/02 File:XX496.out
-------------------------------------------------------------------------
HYDROLOGY CALCULATIONS - EXISTING CONDITION - 100 YEAR STORM
TENTATIVE TRACT NO. 30496 - CITY OF LAKE ELSINORE
ENGINEER: CHRISTINE
-- ----------------------- --- ----------------------------------------------
BV ENGINEERING, One Corporate Park, Irvine, CA - SIN 705
------------------------------------------------------------------------
Rational Method Hydrology Program based on
Riverside County Flood Control & Water Conservation District
1978 hydrology manual
Storm event (year) = 100.00 Antecedent Moisture Condition = 2
Standard intensity-duration curves data (Plate D-4.1)
For the [ Elsinore-Wildomar ] area used.
10 year storm 10 minute intensity = 2 .320 (In/Hr)
10 year storm 60 minute intensity = 0 .980 (In/Hr)
100 year storm 10 minute intensity = 3 .540 (In/Hr)
100 year storm 60 minute intensity = 1.500 (In/Hr)
Storm event year = 100.0
Calculated rainfall intensity data:
1 hour intensity = 1.500 (In/Hr)
Slope of intensity duration curve = 0.4800
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
Process from Point/Station 6.000 to Point/Station 20.000
**** INITIAL AREA EVALUATION **** Al
Initial area flow distance = 920.000 (Ft.)
Top (of initial area) elevation = 1741.000 (Ft.)
Bottom (of initial area) elevation = 1486.500 (Ft. )
Difference in elevation = 254.500 (Ft. )
Slope = 0.27663 s (percent)= 27 .66
TC = k(0 .530) * [ (length^3) / (elevation change) ] '0.2
Initial area time of concentration = 10.505 min.
Rainfall intensity = 3 .462 (In/Hr) for a 100.0 year storm
UNDEVELOPED (poor cover) subarea
Runoff Coefficient = 0.847
Decimal fraction soil group A = 0.000
Decimal fraction soil group B = 0.000
Decimal fraction soil group C = 1.000
Decimal fraction soil group D = 0.000
RI index for soil (AMC 2) = 86.00
Pervious area fraction = 1.000; Impervious fraction = 0.000
Initial subarea runoff = 17.152 (CFS)
Total initial stream area = 5 .850 (Ac.)
Pervious area fraction = 1.000
59
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
Process from Point/Station 20.000 to Point/Station 21.000
**** PIPEFLOW TRAVEL TIME (Program estimated size) ****
Upstream point/station elevation = 1486.500 (Ft. )
Downstream point/station elevation = 1482.000 (Ft.)
Pipe length = 170.00 (Ft. ) Manning's N = 0.013
No. of pipes = 1 Required pipe flow = 17.152 (CFS)
Nearest computed pipe diameter = 18.00 (In.)
Calculated individual pipe flow = 17.152 (CFS)
Normal flow depth in pipe = 14.81(In. )
Flow top width inside pipe = 13 .74 (In.)
Critical depth could not be calculated.
Pipe flow velocity = 11.02 (Ft/s)
Travel time through pipe = 0.26 min.
Time of concentration (TC) = 10.76 min.
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
Process from Point/Station 21.000 to Point/Station 21.000
**** SUBAREA FLOW ADDITION **** A2
UNDEVELOPED (poor cover) subarea
Runoff Coefficient = 0.846
Decimal fraction soil group A = 0 .000
Decimal fraction soil group B = 0 .000
Decimal fraction soil group C = 1.000
Decimal fraction soil group D = 0 .000
RI index for soil (AMC 2) = 86.00
Pervious area fraction = 1.000; Impervious fraction = 0. 000
Time of concentration = 10.76 min.
Rainfall intensity = 3 .422 (In/Hr) for a 100. 0 year storm
Subarea runoff = 10.571 (CFS) for 3.650 (Ac. )
Total runoff = 27.723 (CFS) Total area = 9.500 (Ac.)
60
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
Process from Point/Station 21.000 to Point/Station 22 .000
**** NATURAL CHANNEL TIME + SUBAREA FLOW ADDITION **** A3
Top of natural channel elevation = 1482 .000 (Ft.)
End of natural channel elevation = 1466.200 (Ft.)
Length of natural channel = 360.000 (Ft. )
Estimated mean flow rate at midpoint of channel = 31.152 (CFS)
Natural valley channel type used
L.A. County flood control district formula for channel velocity:
Velocity(ft/s) = (7 + 8 (q(English Units) '.352) (slope"0.5)
Velocity using mean channel flow = 7.09 (Ft/s)
Correction to map slope used on extremely rugged channels with
drops and waterfalls (Plate D-6.2)
Normal channel slope = 0.0439
Corrected/adjusted channel slope = 0.0439
Travel time = 0.85 min. TC = 11.61 min.
Adding area flow to channel
UNDEVELOPED (poor cover) subarea
Runoff Coefficient = 0.844
Decimal fraction soil group A = 0.000
Decimal fraction soil group B = 0.000
Decimal fraction soil group C = 1.000
Decimal fraction soil group D = 0.000
RI index for soil (AMC 2) = 86.00
Pervious area fraction = 1.000; Impervious fraction = 0.000
Rainfall intensity = 3 .300 (In/Hr) for a 100.0 year storm
Subarea runoff = 6.549 (CFS) for 2 .350 (Ac.)
Total runoff = 34 .272 (CFS) Total area = 11.850 (Ac. )
61
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
Process from Point/Station 22.000 to Point/Station 23 .000
**** IMPROVED CHANNEL TRAVEL TIME **** A4
Upstream point elevation = 1466.200 (Ft. )
Downstream point elevation = 1451.000 (Ft.)
Channel length thru subarea = 585.000 (Ft.)
Channel base width = 0.000 (Ft. )
Slope or 'Z' of left channel bank = 1.000
Slope or 'Z' of right channel bank = 1.000
Estimated mean flow rate at midpoint of channel = 55.529 (CFS)
Manning's 'N' = 0.015
Maximum depth of channel = 3.000 (Ft. )
Flow(q) thru subarea = 55.529(CFS)
Depth of flow = 2.069 (Ft. ) , Average velocity = 12.966 (Ft/s)
Channel flow top width = 4.139(Ft.)
Flow Velocity = 12.97 (Ft/s)
Travel time = 0.75 min.
Time of concentration = 12 .36 min.
Sub-Channel No. 1 Critical depth = 2 .859 (Ft. )
' Critical flow top width = 5.719 (Ft.)
' Critical flow velocity= 6.792 (Ft/s)
' ' Critical flow area = 8 .176 (Sq.Ft)
Adding area flow to channel
UNDEVELOPED (poor cover) subarea
Runoff Coefficient = 0. 843
Decimal fraction soil group A = 0.000
Decimal fraction soil group B = 0.000
Decimal fraction soil group C = 1.000
Decimal fraction soil group D = 0.000
RI index for soil (AMC 2) = 86.00
Pervious area fraction = 1.000; Impervious fraction = 0.000
Rainfall intensity = 3 .202 (In/Hr) for a 100.0 year storm
Subarea runoff = 39.673 (CFS) for 14 .700 (Ac.)
Total runoff = 73 .945 (CFS) Total area = 26.550 (Ac. )
62
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
Process from Point/Station 23.000 to Point/Station 24 .000
**** IMPROVED CHANNEL TRAVEL TIME **** A5
Upstream point elevation = 1451.000 (Ft. )
Downstream point elevation = 1432.300 (Ft. )
Channel length thru subarea = 265.000 (Ft. )
Channel base width = 0.000 (Ft. )
Slope or 'Z' of left channel bank = 1.000
Slope or 'Z' of right channel bank = 1.000
Estimated mean flow rate at midpoint of channel = 77.775 (CFS)
Manning's 'N' = 0.015
Maximum depth of channel = 2.000 (Ft. )
Flow(q) thru subarea = 77.775 (CFS)
Depth of flow = 1.947 (Ft.) , Average velocity = 20.517 (Ft/s)
Channel flow top width = 3.894 (Ft.)
Flow Velocity = 20.52 (Ft/s)
Travel time = 0 .22 min.
Time of concentration = 12.58 min.
Sub-Channel No. 1 Critical depth = 3 .281 (Ft. )
' Critical flow top width = 4.000 (Ft.)
' ' ' Critical flow velocity= 8 .523 (Ft/s)
' Critical flow area = 9.125 (Sq.Ft)
Adding area flow to channel
UNDEVELOPED (poor cover) subarea
Runoff Coefficient = 0.842
i
Decimal fraction soil group A = 0.000
Decimal fraction soil group B = 0.000
Decimal fraction soil group C = 1.000
Decimal fraction soil group D = 0.000
RI index for soil (AMC 2) = 86.00
Pervious area fraction = 1.000; Impervious fraction = 0.000
Rainfall intensity = 3.176 (In/Hr) for a 100.0 year storm
Subarea runoff = 7.357 (CFS) for 2 .750 (Ac. )
Total runoff = 81.302 (CFS) Total area = 29.300.(Ac.)
Q100 = 81.3 cfs Discharges to a low point
63
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
Process from Point/Station 3.000 to Point/Station 4.000
**** INITIAL AREA EVALUATION **** B1
Initial area flow distance = 990.000 (Ft. )
Top (of initial area) elevation = 1761.000 (Ft. )
Bottom (of initial area) elevation = 1488 .700 (Ft. )
Difference in elevation = 272.300 (Ft. )
Slope = 0.27505 s (percent)= 27.51
TC = k(0.530) *[ (length'3) / (elevation change) ] '0 .2
Initial area time of concentration = 10 .830 min.
Rainfall intensity = 3 .412 (In/Hr) for a 100.0 year storm
UNDEVELOPED (poor cover) subarea
Runoff Coefficient = 0.846
Decimal fraction soil group A = 0.000
Decimal fraction soil group B = 0.000
Decimal fraction soil group C = 1.000
Decimal fraction soil group D = 0.000
RI index for soil (AMC 2) = 86.00
Pervious area fraction = 1.000; Impervious fraction = 0.000
Initial subarea runoff = 17.033 (CFS)
Total initial stream area = 5.900 (Ac. )
Pervious area fraction = 1.000
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
Process from Point/Station 4.000 to Point/Station 4.000
**** SUBAREA FLOW ADDITION **** B2
UNDEVELOPED (poor cover) subarea
Runoff Coefficient = 0.846
Decimal fraction soil group A = 0. 000
Decimal fraction soil group B = 0. 000
Decimal fraction soil group C = 1.000
Decimal fraction soil group D = 0.000
RI index for soil (AMC 2) = 86.00
Pervious area fraction = 1.000; Impervious fraction = 0.000
Time of concentration = 10.83 min.
Rainfall intensity = 3 .412 (In/Hr) for a 100.0 year storm
Subarea runoff = 14. 867 (CFS) for 5.150 (Ac.)
Total runoff = 31.900 (CFS) Total area = 11.050 (Ac. )
64
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
Process from Point/Station 4.000 to Point/Station 5.000
**** IMPROVED CHANNEL TRAVEL TIME **** B3 + B4
Upstream point elevation = 1488.700 (Ft.)
Downstream point elevation = 1470.400 (Ft. )
Channel length thru subarea = 790.000 (Ft. )
Channel base width = 0.000 (Ft.)
Slope or 'Z' of left channel bank = 1.000
Slope or 'Z' of right channel bank = 1.000
Estimated mean flow rate at midpoint of channel = 53 .768 (CFS)
Manning's 'N' = 0.015
Maximum depth of channel = 3 .000 (Ft.)
Flow(q) thru subarea = 53 .768 (CFS)
Depth of flow = 2 .089 (Ft.) , Average velocity = 12.320 (Ft/s)
Channel flow top width = 4.178 (Ft.)
Flow Velocity = 12 .32 (Ft/s)
Travel time = 1.07 min.
Time of concentration = 11.90 min.
Sub-Channel No. 1 Critical depth = 2 .828 (Ft. )
' Critical flow top width = 5.656 (Ft.)
' ' ' Critical flow velocity= 6.722 (Ft/s)
' ' Critical flow area = 7.998 (Sq.Ft)
Adding area flow to channel
UNDEVELOPED (poor cover) subarea
Runoff Coefficient = 0.844
Decimal fraction soil group A = 0.000
Decimal fraction soil group B = 0.000
Decimal fraction soil group C = 1.000
Decimal fraction soil group D = 0.000
RI index for soil (AMC 2) = 86.00
Pervious area fraction = 1.000; Impervious fraction = 0.000
Rainfall intensity = 3 .261 (In/Hr) for a 100.0 year storm
Subarea runoff = 41.689 (CFS) for 15 .150 (Ac. )
Total runoff = 73 .589 (CFS) Total area = 26.200.(Ac.)
4100 = 73 .6 cfs Discharges to a low point
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
Process from Point/Station 5.000 to Point/Station 5.100
**** PIPEFLOW TRAVEL TIME (Program estimated size) ****
Upstream point/station elevation = 1470.400 (Ft. )
Downstream point/station elevation = 1449. 000 (Ft. )
Pipe length = 85 .00 (Ft.) Manning's N = 0. 013
No. of pipes = 1 Required pipe flow = 73 .589(CFS)
Nearest computed pipe diameter = 21.00 (In. )
Calculated individual pipe flow = 73 .589 (CFS)
Normal flow depth in pipe = 15.96 (In. )
Flow top width inside pipe = 17.94 (In.)
Critical depth could not be calculated.
Pipe flow velocity = 37.53 (Ft/s)
Travel time through pipe = 0.04 min.
Time of concentration (TC) = 11.94 min.
65
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
Process from Point/Station 5.100 to Point/Station 5.100
**** SUBAREA FLOW ADDITION **** B5
COMMERCIAL subarea type
Runoff Coefficient = 0.886
Decimal fraction soil group A = 0. 000
Decimal fraction soil group B = 0 . 000
Decimal fraction soil group C = 1. 000
Decimal fraction soil group D = 0 . 000
RI index for soil (AMC 2) = 69.00
Pervious area fraction = 0.100; Impervious fraction = 0 .900
Time of concentration = 11.94 min.
Rainfall intensity = 3.256 (In/Hr) for a 100.0 year storm
Subarea runoff = 5.337 (CFS) for 1.850 (Ac. )
Total runoff = 78.927 (CFS) Total area = 28.050 (Ac. )
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
Process from Point/Station 5.100 to Point/Station 5.100
**** SUBAREA FLOW ADDITION **** B7
COMMERCIAL subarea type
Runoff Coefficient = 0.886
Decimal fraction soil group A = 0. 000
Decimal fraction soil group B = 0. 000
Decimal fraction soil group C = 1. 000
Decimal fraction soil group D = 0. 000
RI index for soil (AMC 2) = 69.00
Pervious area fraction = 0.100; Impervious fraction = 0 .900
Time of concentration = 11.94 min.
Rainfall intensity = 3 .256 (In/Hr) for a 100.0 year storm
Subarea runoff = 3 .029 (CFS) for 1.050 (Ac.)
Total runoff = 81.956 (CFS) Total area = 29.100 (Ac.)
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
Process from Point/Station 5.100 to Point/Station 5.200
**** PIPEFLOW TRAVEL TIME (Program estimated size) ****
Upstream point/station elevation = 1449.000 (Ft. )
Downstream point/station elevation = 1447 .000 (Ft. )
Pipe length = 100.00 (Ft.) Manning's N = 0. 013
No. of pipes = 1 Required pipe flow = 81.956(CFS)
Nearest computed pipe diameter = 36.00 (In. )
Calculated individual pipe flow = 81.956 (CFS)
Normal flow depth in pipe = 25 .92 (In.)
Flow top width inside pipe = 32.33 (In.)
Critical Depth = 33 .44 (In. )
Pipe flow velocity = 15.03 (Ft/s)
Travel time through pipe = 0. 11 min.
Time of concentration (TC) = 12 .05 min.
66
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
Process from Point/Station 5.200 to Point/Station 5.200
**** SUBAREA FLOW ADDITION **** B6
COMMERCIAL subarea type
Runoff Coefficient = 0.886
Decimal fraction soil group A = 0.000
Decimal fraction soil group B = 0.000
Decimal fraction soil group C = 1.000
Decimal fraction soil group D = 0.000
RI index for soil (AMC 2) = 69.00
Pervious area fraction = 0.100; Impervious fraction = 0.900
Time of concentration = 12.05 min.
Rainfall intensity = 3 .242 (In/Hr) for a 100.0 year storm
Subarea runoff = 1.436 (CFS) for 0.500 (Ac. )
Total runoff = 83 .392 (CFS) Total area = 29.600 (Ac.)
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
Process from Point/Station 5.200 to Point/Station 5.200
**** SUBAREA FLOW ADDITION **** B8
COMMERCIAL subarea type
Runoff Coefficient = 0 .886
Decimal fraction soil group A = 0.000
Decimal fraction soil group B = 0.000
Decimal fraction soil group C = 1.000
Decimal fraction soil group D = 0.000
RI index for soil (AMC 2) = 69.00
Pervious area fraction = 0.100; Impervious fraction = 0.900
Time of concentration = 12.05 min.
Rainfall intensity = 3 .242 (In/Hr) for a 100 .0 year storm
Subarea runoff = 1.005 (CFS) for 0.350 (Ac. )
Total runoff = 84 .397 (CFS) Total area = 29.950 (Ac.)
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
Process from Point/Station 5.200 to Point/Station 5.300
**** PIPEFLOW TRAVEL TIME (Program estimated size) ****
Upstream point/station elevation = 1447.000 (Ft. )
Downstream point/station elevation = 1440.000 (Ft.)
Pipe length = 245.00 (Ft.) Manning's N = 0.013
No. of pipes = 1 Required pipe flow = 84.397 (CFS)
Nearest computed pipe diameter = 33 .00 (In.)
Calculated individual pipe flow = 84 .397 (CFS)
Normal flow depth in pipe = 25.55 (In.)
Flow top width inside pipe = 27.60 (In. )
Critical depth could not be calculated.
Pipe flow velocity = 17.12 (Ft/s)
Travel time through pipe = 0.24 min.
Time of concentration (TC) = 12 .29 min.
67
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
Process from Point/Station 5.300 to Point/Station 5.300
**** CONFLUENCE OF MINOR STREAMS ****
Along Main Stream number: 1 in normal stream number 1
Stream flow area = 29.950 (Ac. )
Runoff from this stream = 84.397 (CFS)
Time of concentration = 12.29 min.
Rainfall intensity = 3 .211 (In/Hr)
Confluence with Subarea "E"
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
Process from Point/Station 10.000 to Point/Station 11.000
**** INITIAL AREA EVALUATION **** E
Initial area flow distance = 640.000 (Ft.)
Top (of initial area) elevation = 1515 .000 (Ft.)
Bottom (of initial area) elevation = 1446.500 (Ft.)
Difference in elevation = 68.500 (Ft. )
Slope = 0.10703 s (percent) = 10.70
TC = k(0.530) * [ (length"3) / (elevation change) ] "0.2
Initial area time of concentration = 10.986 min.
Rainfall intensity = 3 .388 (In/Hr) for a 100.0 year storm
UNDEVELOPED (poor cover) subarea
Runoff Coefficient = 0 .846
Decimal fraction soil group A = 0 .000
Decimal fraction soil group B = 0.000
Decimal fraction soil group C = 1.000
Decimal fraction soil group D = 0.000
RI index for soil (AMC 2) = 86.00
Pervious area fraction = 1.000; Impervious fraction = 0.000
Initial subarea runoff = 7.881 (CFS)
Total initial stream area = 2 .750 (Ac.)
Pervious area fraction = 1. 000
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
Process from Point/Station 11.000 to Point/Station 5.300
**** PIPEFLOW TRAVEL TIME (Program estimated size) ****
Upstream point/station elevation = 1446.500 (Ft. )
Downstream point/station elevation = 1440.000 (Ft. )
Pipe length = 80 .00 (Ft. ) Manning's N = 0.013
No. of pipes = 1 Required pipe flow = 7.881 (CFS)
Nearest computed pipe diameter = 12 .00 (In.)
Calculated individual pipe flow = 7.881 (CFS)
Normal flow depth in pipe = 7.95 (In.)
Flow top width inside pipe = 11.35 (In. )
Critical depth could not be calculated.
Pipe flow velocity = 14.29 (Ft/s)
Travel time through pipe = 0.09 min.
Time of concentration (TC) = 11.08 min.
68
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
Process from Point/Station 5.300 to Point/Station 5.300
**** CONFLUENCE OF MINOR STREAMS ****
Along Main Stream number: 1 in normal stream number 2
Stream flow area = 2 .750 (Ac. )
Runoff from this stream = 7.881 (CFS)
Time of concentration = 11.08 min.
Rainfall intensity = 3.375 (In/Hr)
Summary of stream data:
Stream Flow rate TC Rainfall Intensity
No. (CFS) (min) (In/Hr)
1 84.397 12 .29 3 .211
2 7. 881 11.08 3 .375
Largest stream flow has longer time of concentration
Qp = 84 .397 + sum of
Qb Ia/Ib
7. 881 * 0.952 = 7.500
Qp = 91.897
Total of 2 streams to confluence:
Flow rates before confluence point:
84 .397 7. 881
Area of streams before confluence:
29.950 2 .750
Results of confluence:
Total flow rate = 91.897 (CFS)
Time of concentration = 12.286 min.
Effective stream area after confluence = 32.700 (Ac. )
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
Process from Point/Station 5.300 to Point/Station 11.100
**** PIPEFLOW TRAVEL TIME (Program estimated size) ****
Upstream point/station elevation = 1440 .000 (Ft. )
Downstream point/station elevation = 1420.000 (Ft.)
Pipe length = 80.00 (Ft. ) Manning' s N = 0.013
No. of pipes = 1 Required pipe flow = 91.897 (CFS)
Nearest computed pipe diameter = 24.00 (In. )
Calculated individual pipe flow = 91.897 (CFS)
Normal flow depth in pipe = 16.43 (In. )
Flow top width inside pipe = 22 .30 (In.)
Critical depth could not be calculated.
Pipe flow velocity = 40.11(Ft/s)
Travel time through pipe = 0.03 min.
Time of concentration (TC) = 12 .32 min.
QiOo = 91. 9 cfs Discharges to Cottonw000d Creek
j
69
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
Process from Point/Station 12 .000 to Point/Station 12.100
**** INITIAL AREA EVALUATION **** C
Initial area flow distance = 170.000 (Ft.)
Top (of initial area) elevation = 1500.000 (Ft. )
Bottom (of initial area) elevation = 1482 .900 (Ft.)
Difference in elevation = 17.100 (Ft.)
Slope = 0.10059 s (percent)= 10.06
TC = k(0.530) * [ (length"3) / (elevation change) ] A0.2
Initial area time of concentration = 6.546 min.
Rainfall intensity = 4.345 (In/Hr) for a 100.0 year storm
UNDEVELOPED (poor cover) subarea
Runoff Coefficient = 0.857
Decimal fraction soil group A = 0.000
Decimal fraction soil group B = 0.000
Decimal fraction soil group C = 1.000
Decimal fraction soil group D = 0.000
RI index for soil (AMC 2) = 86.00
Pervious area fraction = 1.000; Impervious fraction = 0.000
Initial subarea runoff = 1.676 (CFS)
Total initial stream area = 0.450 (Ac.)
Pervious area fraction = 1.000
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
Process from Point/Station 12 .100 to Point/Station 12 .200
**** PIPEFLOW TRAVEL TIME (Program estimated size) ****
Upstream point/station elevation = 1482 .900 (Ft. )
Downstream point/station elevation = 1460.000 (Ft.)
Pipe length = 190.00 (Ft.) Manning's N = 0.013
No. of pipes = 1 Required pipe flow = 1.676 (CFS)
Nearest computed pipe diameter = 6.00 (In. )
Calculated individual pipe flow = 1.676 (CFS)
Normal flow depth in pipe = 4.29 (In. )
Flow top width inside pipe = 5.42 (In.)
Critical depth could not be calculated.
Pipe flow velocity = 11.16 (Ft/s)
Travel time through pipe = 0.28 min.
Time of concentration (TC) = 6.83 min.
4100 = 1.7 cfs Discharges to Cottonwood Creek
70
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
Process from Point/Station 6.000 to Point/Station 7.000
**** INITIAL AREA EVALUATION **** D1
Initial area flow distance = 900.000(Ft. )
Top (of initial area) elevation = 1741.000 (Ft.)
Bottom (of initial area) elevation = 1478 .200 (Ft. )
Difference in elevation = 262 .800 (Ft. )
Slope = 0.29200 s (percent) = 29.20
TC = k(0 .530) * [ (length~3) / (elevation change) ] A0.2
Initial area time of concentration = 10.301 min.
Rainfall intensity = 3 .495 (In/Hr) for a 100.0 year storm
UNDEVELOPED (poor cover) subarea
Runoff Coefficient = 0.847
Decimal fraction soil group A = 0 .000
Decimal fraction soil group B = 0 .000
Decimal fraction soil group C = 1.000
Decimal fraction soil group D = 0 .000
RI index for soil (AMC 2) = 86.00
Pervious area fraction = 1.000; Impervious fraction = 0.000
Initial subarea runoff = 19.101(CFS)
Total initial stream area = 6.450 (Ac.)
Pervious area fraction = 1.000
4100 = 19 .1 cfs Enters project site @ project boundary
71
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
Process from Point/Station 7. 000 to Point/Station 8.000
**** IMPROVED CHANNEL TRAVEL TIME **** D2
Upstream point elevation = 1478.200 (Ft. )
Downstream point elevation = 1448.500 (Ft. )
Channel length thru subarea = 660.000 (Ft.)
Channel base width = 0.000 (Ft. )
Slope or 'Z' of left channel bank = 1. 000
Slope or 'Z' of right channel bank = 1.000
Estimated mean flow rate at midpoint of channel = 22.580 (CFS)
Manning's 'N' = 0.015
Maximum depth of channel = 2.000 (Ft. )
Flow(q) thru subarea = 22 .580 (CFS)
Depth of flow = 1.332 (Ft.) , Average velocity = 12 .722 (Ft/s)
Channel flow top width = 2.664 (Ft. )
Flow Velocity = 12 .72 (Ft/s)
Travel time = 0.86 min.
Time of concentration = 11.17 min.
Sub-Channel No. 1 Critical depth = 2 .000 (Ft. )
' ' Critical flow top width = 4.000 (Ft.)
' Critical flow velocity= 5.645 (Ft/s)
' ' ' Critical flow area = 4. 000 (Sq.Ft)
Adding area flow to channel
UNDEVELOPED (poor cover) subarea
Runoff Coefficient = 0.845
Decimal fraction soil group A = 0.000
Decimal fraction soil group B = 0.000
Decimal fraction soil group C = 1.000
Decimal fraction soil group D = 0.000
RI index for soil (AMC 2) = 86.00
Pervious area fraction = 1.000; Impervious fraction = 0.000
Rainfall intensity = 3.362 (In/Hr) for a 100.0 year storm
Subarea runoff = 6.680 (CFS) for 2.350 (Ac. )
Total runoff = 25.780 (CFS) Total area = B.B00 (Ac. )
72
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
Process from Point/Station 8.000 to Point/Station 9.000
**** IMPROVED CHANNEL TRAVEL TIME **** D3 + D4
Upstream point elevation = 1448.500 (Ft.)
Downstream point elevation = 1440.800 (Ft. )
Channel length thru subarea = 300.000 (Ft. )
Channel base width = 0.000 (Ft.)
Slope or 'Z' of left channel bank = 1.000
Slope or 'Z' of right channel bank = 1.000
Estimated mean flow rate at midpoint of channel = 46.653 (CFS)
Manning's 'N' = 0.015
Maximum depth of channel = 2.000 (Ft.)
Flow(q) thru subarea = 46.653 (CFS)
Depth of flow = 1.943 (Ft. ) , Average velocity = 12.357 (Ft/s)
Channel flow top width = 3 .886 (Ft. )
Flow Velocity = 12.36 (Ft/s)
Travel time = 0.40 min.
Time of concentration = 11.57 min.
Sub-Channel No. 1 Critical depth = 2.625 (Ft. )
' Critical flow top width = 4.000 (Ft. )
' Critical flow velocity= 7.177 (Ft/s)
' ' ' Critical flow area = 6.500 (Sq.Ft)
Adding area flow to channel
UNDEVELOPED (poor cover) subarea
Runoff Coefficient = 0 . 845
Decimal fraction soil group A = 0.000
Decimal fraction soil group B = 0.000
Decimal fraction soil group C = 1.000
Decimal fraction soil group D = 0.000
RI index for soil (AMC 2) = 86.00
Pervious area fraction = 1.000; Impervious fraction = 0.000
Rainfall intensity = 3 .305 (In/Hr) for a 100.0 year storm
Subarea runoff = 39.776 (CFS) for 14.250 (Ac.)
Total runoff = 65.557 (CFS) Total area = 23.050 (Ac.)
43.00 = 65 . 6 cfs Discharges to a low point
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
Process from Point/Station 9.000 to Point/Station 9.100
**** PIPEFLOW TRAVEL TIME (Program estimated size) ****
Upstream point/station elevation = 1440.800 (Ft. )
Downstream point/station elevation = 1433 .700 (Ft. )
Pipe length = 40.00 (Ft. ) Manning's N = 0 .013
No. of pipes = 1 Required pipe flow = 65 .557 (CFS)
Nearest computed pipe diameter = 21.00 (In. )
Calculated individual pipe flow = 65.557 (CFS)
Normal flow depth in pipe = 16.88 (In. )
Flow top width inside pipe = 16.69 (In.)
Critical depth could not be calculated.
Pipe flow velocity = 31.64 (Ft/s)
Travel time through pipe = 0.02 min.
I Time of concentration (TC) = 11.59 min.
73
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
Process from Point/Station 9.100 to Point/Station 9.100
**** SUBAREA FLOW ADDITION **** D5
COMMERCIAL subarea type
Runoff Coefficient = 0. 886
Decimal fraction soil group A = 0.000
Decimal fraction soil group B = 0.000
Decimal fraction soil group C = 1.000
Decimal fraction soil group D = 0.000
RI index for soil(AMC 2) = 69.00
Pervious area fraction = 0.100; Impervious fraction = 0.900
Time of concentration = 11.59 min.
Rainfall intensity = 3 .302 (In/Hr) for a 100.0 year storm
Subarea runoff = 1.756 (CFS) for 0.600 (Ac. )
Total runoff = 67.312 (CFS) Total area = 23.650 (Ac.)
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
Process from Point/Station 9.100 to Point/Station 9.100
**** SUBAREA FLOW ADDITION **** D6
COMMERCIAL subarea type
Runoff Coefficient = 0. 886
Decimal fraction soil group A = 0.000
Decimal fraction soil group B = 0.000
Decimal fraction soil group C = 1.000
Decimal fraction soil group D = 0.000
RI index for soil (AMC 2) = 69.00
Pervious area fraction = 0.100; Impervious fraction = 0.900
Time of concentration = 11.59 min.
Rainfall intensity = 3 .302 (In/Hr) for a 100.0 year storm
Subarea runoff = 0 .878 (CFS) for 0.300 (Ac. )
Total runoff = 68.190 (CFS) Total area = 23 .950 (Ac. )
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
Process from Point/Station 9.100 to Point/Station 9.200
**** PIPEFLOW TRAVEL TIME (Program estimated size) ****
Upstream point/station elevation = 1433.700 (Ft. )
Downstream point/station elevation = 1422 .900 (Ft.)
Pipe length = 95.00 (Ft. ) Manning's N = 0 .013
No. of pipes = 1 Required pipe flow = 68 .190 (CFS)
Nearest computed pipe diameter = 24.00 (In. )
Calculated individual pipe flow = 68.190 (CFS)
Normal flow depth in pipe = 17.70 (In. )
Flow top width inside pipe = 21.12 (In.)
Critical depth could not be calculated.
Pipe flow velocity = 27.45 (Ft/s)
Travel time through pipe = 0.06 min.
Time of concentration (TC) 11.65 min.
74
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
Process from Point/Station 9.200 to Point/Station 9.200
**** SUBAREA FLOW ADDITION **** D7
COMMERCIAL subarea type
Runoff Coefficient = 0.886
Decimal fraction soil group A = 0.000
Decimal fraction soil group B = 0.000
Decimal fraction soil group C = 1.000
Decimal fraction soil group D = 0.000
RI index for soil (AMC 2) = 69.00
Pervious area fraction = 0.100; Impervious fraction = 0.900
Time of concentration = 11.65 min.
Rainfall intensity = 3 .294 (In/Hr) for a 100.0 year storm
Subarea runoff = 1.752 (CFS) for 0.600 (Ac. )
Total runoff = 69.942 (CFS) Total area = 24.550 (Ac. )
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
Process from Point/Station 9.200 to Point/Station 9.200
**** SUBAREA FLOW ADDITION **** D8
COMMERCIAL subarea type
Runoff Coefficient = 0.886
Decimal fraction soil group A = 0.000
Decimal fraction soil group B = 0.000
Decimal fraction soil group C = 1.000
Decimal fraction soil group D = 0.000
RI index for soil (AMC 2) = 69.00
Pervious area fraction = 0.100; Impervious fraction = 0.900
Time of concentration = 11.65 min.
Rainfall intensity = 3 .294 (In/Hr) for a 100 .0 year storm
Subarea runoff = 0.876 (CFS) for 0.300 (Ac. )
Total runoff = 70.818 (CFS) Total area = 24.850 (Ac. )
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
Process from Point/Station 9.200 to Point/Station 9.300
**** PIPEFLOW TRAVEL TIME (Program estimated size) ****
Upstream point/station elevation = 1422.900 (Ft.)
Downstream point/station elevation = 1422 .000 (Ft. )
Pipe length = 65.00 (Ft. ) Manning's N = 0.013
No. of pipes = 1 Required pipe flow = 70.818 (CFS)
Nearest computed pipe diameter = 36.00 (In. )
Calculated individual pipe flow = 70.818 (CFS)
Normal flow depth in pipe = 26.77 (In. )
Flow top width inside pipe = 31.44 (In.)
Critical Depth = 32.03 (In. )
Pipe flow velocity = 12 .57 (Ft/s)
Travel time through pipe = 0.09 min.
Time of concentration (TC) = 11.74 min.
Q100 = 70 .8 cfs Discharges to Cottonwood Creek
75
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
Process from Point/Station 25 .000 to Point/Station 26.000
**** INITIAL AREA EVALUATION **** F1
Initial area flow distance = 795.000 (Ft. )
Top (of initial area) elevation = 1701.000 (Ft. )
Bottom (of initial area) elevation = 1446.000 (Ft. )
Difference in elevation = 255.000 (Ft. )
Slope = 0.32075 s (percent)= 32 .08
TC = k(0.530) * [ (length'3) / (elevation change) ] '0 .2
Initial area time of concentration = 9.620 min.
Rainfall intensity = 3.611(In/Hr) for a 100 .0 year storm
UNDEVELOPED (poor cover) subarea
Runoff Coefficient = 0.849
Decimal fraction soil group A = 0.000
Decimal fraction soil group B = 0.000
Decimal fraction soil group C = 1.000
Decimal fraction soil group D = 0.000
RI index for soil (AMC 2) = 86.00
Pervious area fraction = 1.000; Impervious fraction = 0.000
Initial subarea runoff = 10.884 (CFS)
Total initial stream area = 3 .550 (Ac.)
Pervious area fraction = 1.000
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
Process from Point/Station 26.000 to Point/Station 27.000
**** IMPROVED CHANNEL TRAVEL TIME **** F2
Upstream point elevation = 1446.000 (Ft. )
Downstream point elevation = 1438 . 000 (Ft.)
Channel length thru subarea = 20 .000 (Ft.)
Channel base width = 0.000 (Ft. )
Slope or 'Z' of left channel bank = 1.000
Slope or 'Z' of right channel bank = 1.000
Manning's 'N' = 0.015
Maximum depth of channel = 2.000 (Ft. )
Flow(q) thru subarea = 10.884 (CFS)
Depth of flow = 0.673 (Ft.) , Average velocity = 24.052 (Ft/s)
Channel flow top width = 1.345 (Ft. )
Flow Velocity = 24 . 05 (Ft/s)
Travel time = 0. 01 min.
Time of concentration = 9.63 min.
Sub-Channel No. 1 Critical depth = 1.492 (Ft. )
' Critical flow top width = 2.984 (Ft.)
' Critical flow velocity= 4 .888 (Ft/s)
' ' Critical flow area = 2 .227 (Sq.Ft)
76
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
Process from Point/Station 27.000 to Point/Station 27.000
**** SUBAREA FLOW ADDITION **** F2
UNDEVELOPED (poor cover) subarea
Runoff Coefficient = 0.849
Decimal fraction soil group A = 0.000
Decimal fraction soil group B = 0.000
Decimal fraction soil group C = 1.000
Decimal fraction soil group D = 0.000
RI index for soil (AMC 2) = 86.00
Pervious area fraction = 1.000; Impervious fraction = 0.000
Time of concentration = 9.63 min.
Rainfall intensity = 3 .609(In/Hr) for a 100.0 year storm
Subarea runoff = 0.460 (CFS) for 0.150 (Ac. )
Total runoff = 11.344 (CFS) Total area = 3 .700 (Ac. )
4100 = 11.3 cfs Discharges to a low point
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
Process from Point/Station 30.000 to Point/Station 31.000
**** INITIAL AREA EVALUATION **** G1
Initial area flow distance = 975.000 (Ft.)
Top (of initial area) elevation = 1633.600 (Ft. )
Bottom (of initial area) elevation = 1425.000 (Ft. )
Difference in elevation = 208.600 (Ft.)
Slope = 0.21395 s (percent) = 21.39
TC = k(0.530) * [ (length^3) / (elevation change) ] '0.2
Initial area time of concentration = 11.319 min.
Rainfall intensity = 3 .340 (In/Hr) for a 100.0 year storm
UNDEVELOPED (poor cover) subarea
Runoff Coefficient = 0.845
Decimal fraction soil group A = 0.000
Decimal fraction soil group B = 0.000
Decimal fraction soil group C = 1.000
Decimal fraction soil group D = 0.000
RI index for soil (AMC 2) = 86.00
Pervious area fraction = 1.000; Impervious fraction = 0 .000
Initial subarea runoff = 17.360 (CFS)
Total initial stream area = 6.150 (Ac. )
Pervious area fraction = 1.000
77
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
Process from Point/Station 31.000 to Point/Station 32 .000
**** NATURAL CHANNEL TIME + SUBAREA FLOW ADDITION **** G2
Top of natural channel elevation = 1425.000 (Ft. )
End of natural channel elevation = 1392 .000 (Ft. )
Length of natural channel = 545.000 (Ft. )
Estimated mean flow rate at midpoint of channel = 29.074 (CFS)
Natural valley channel type used
L.A. County flood control district formula for channel velocity:
Velocity(ft/s) _ (7 + 8 (q(English Units) ^.352) (slope'0.5)
Velocity using mean channel flow = 8.17 (Ft/s)
Correction to map slope used on extremely rugged channels with
drops and waterfalls (Plate D-6.2)
Normal channel slope = 0.0606
Corrected/adjusted channel slope = 0.0606
Travel time = 1.11 min. TC = 12 .43 min.
Adding area flow to channel
UNDEVELOPED (poor cover) subarea
Runoff Coefficient = 0.843
Decimal fraction soil group A = 0.000
Decimal fraction soil group B = 0.000
Decimal fraction soil group C = 1.000
Decimal fraction soil group D = 0.000
RI index for soil (AMC 2) = 86.00
Pervious area fraction = 1.000; Impervious fraction = 0 .000
Rainfall intensity = 3 .193 (In/Hr) for a 100 .0 year storm
Subarea runoff = 22.336 (CFS) for 8.300 (Ac. )
Total runoff = 39.696 (CFS) Total area = 14.450 (Ac.)
7s
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
Process from Point/Station 32 .000 to Point/Station 33 .000
**** NATURAL CHANNEL TIME + SUBAREA FLOW ADDITION **** G3
Top of natural channel elevation = 1392 .000 (Ft. )
End of natural channel elevation = 1390.000 (Ft.)
Length of natural channel = 50 .000 (Ft. )
Estimated mean flow rate at midpoint of channel = 48.830 (CFS)
Natural valley channel type used
L.A. County flood control district formula for channel velocity:
Velocity(ft/s) _ (7 + 8 (q(English Units) '.352) (slope'0.5)
Velocity using mean channel flow = 7.69 (Ft/s)
Correction to map slope used on extremely rugged channels with
drops and waterfalls (Plate D-6.2)
Normal channel slope = 0 .0400
Corrected/adjusted channel slope = 0 .0400
Travel time = 0.11 min. TC = 12.54 min.
Adding area flow to channel
UNDEVELOPED (poor cover) subarea
Runoff Coefficient = 0.842
Decimal fraction soil group A = 0.000
Decimal fraction soil group B = 0 .000
Decimal fraction soil group C = 1.000
Decimal fraction soil group D = 0.000
I RI index for soil(AMC 2) = 86.00
Pervious area fraction = 1.000; Impervious fraction = 0.000
Rainfall intensity = 3.180 (In/Hr) for a 100.0 year storm
Subarea runoff = 17 .816 (CFS) for 6.650 (Ac.)
Total runoff = 57.512 (CFS) Total area = 21.100 (Ac.)
79
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
Process from Point/Station 33 .000 to Point/Station 34.000
**** NATURAL CHANNEL TIME + SUBAREA FLOW ADDITION **** G4
Top of natural channel elevation = 1390.000 (Ft.)
End of natural channel elevation = 1365.000 (Ft. )
Length of natural channel = 455.000 (Ft. )
Estimated mean flow rate at midpoint of channel = 63.576 (CFS)
Natural valley channel type used
L.A. County flood control district formula for channel velocity:
Velocity(ft/s) = (7 + 8 (q(English Units) ".352) (slope'0.5)
Velocity using mean channel flow = 9.73 (Ft/s)
Correction to map slope used on extremely rugged channels with
drops and waterfalls (Plate D-6.2)
Normal channel slope = 0.0549
Corrected/adjusted channel slope = 0.0549
Travel time = 0 .78 min. TC = 13.32 min.
Adding area flow to channel
UNDEVELOPED (poor cover) subarea
Runoff Coefficient = 0.841
Decimal fraction soil group A = 0.000
Decimal fraction soil group B = 0.000 '
Decimal fraction soil group C = 1.000
Decimal fraction soil group D = 0.000
RI index for soil (AMC 2) = 86.00
Pervious area fraction = 1.000; Impervious fraction = 0.000
Rainfall intensity = 3 .089 (In/Hr) for a 100.0 year storm
Subarea runoff = 11.560 (CFS) for 4.450 (Ac.)
Total runoff = 69.072 (CFS) Total area = 25.550 (Ac. )
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
Process from Point/Station 34.000 to Point/Station 34.000
**** SUBAREA FLOW ADDITION **** G5
UNDEVELOPED (poor cover) subarea
Runoff Coefficient = 0.841
Decimal fraction soil group A = 0.000
Decimal fraction soil group B = 0.000
Decimal fraction soil group C = 1.000
Decimal fraction soil group D = 0 .000
RI index for soil (AMC 2) = 86.00
Pervious area fraction = 1.000; Impervious fraction = 0.000
Time of concentration = 13 .32 min.
Rainfall intensity = 3 .089 (In/Hr) for a 100.0 year storm
Subarea runoff = 27.537 (CFS) for 10 .600 (Ac.)
Total runoff = 96.609 (CFS) Total area = 36.150 (Ac. )
80
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
Process from Point/Station 34.000 to Point/Station 35.000
**** NATURAL CHANNEL TIME + SUBAREA FLOW ADDITION **** G6
Top of natural channel elevation = 1365.000 (Ft. )
End of natural channel elevation = 1304.000 (Ft. )
Length of natural channel = 925.000 (Ft. )
Estimated mean flow rate at midpoint of channel = 112 .310 (CFS)
Natural valley channel type used
L.A. County flood control district formula for channel velocity:
velocity(ft/s) _ (7 + 8 (q(English Units) '.352) (slope^0 .5)
Velocity using mean channel flow = 12.62 (Ft/s)
Correction to map slope used on extremely rugged channels with
drops and waterfalls (Plate D-6.2)
Normal channel slope = 0.0659
Corrected/adjusted channel slope = 0.0659
Travel time = 1.22 min. TC = 14.54 min.
Adding area flow to channel
UNDEVELOPED (poor cover) subarea
Runoff Coefficient = 0.839
Decimal fraction soil group A = 0.000
Decimal fraction soil group B = 0.000
Decimal fraction soil group C = 1.000
Decimal fraction soil group D = 0.000
RI index for soil (AMC 2) = 86. 00
Pervious area fraction = 1.000; Impervious fraction = 0 .000
Rainfall intensity = 2 .962 (In/Hr) for a 100.0 year storm
Subarea runoff = 29.183 (CFS) for 11.750 (Ac. )
Total runoff = 125.792 (CFS) Total area = 47.900 (Ac. )
4100 = 125 .8 cfs Discharges to San Jacinto River
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
Process from Point/Station 36.000 to Point/Station 37.000
**** INITIAL AREA EVALUATION **** Hi
Initial area flow distance = 835.000 (Ft. )
Top (of initial area) elevation = 1615 .000 (Ft.)
Bottom (of initial area) elevation = 1447.700 (Ft. )
Difference in elevation = 167.300 (Ft.)
Slope = 0.20036 s (percent) = 20.04
TC = k(0.530) * [ (length"3) / (elevation change) ] '0.2
Initial area time of concentration = 10 .779 min.
Rainfall intensity = 3 .419 (In/Hr) for a 100. 0 year storm
UNDEVELOPED (poor cover) subarea
Runoff Coefficient = 0.846
Decimal fraction soil group A = 0.000
Decimal fraction soil group B = 0.000
Decimal fraction soil group C = 1.000
Decimal fraction soil group D = 0.000
RI index for soil (AMC 2) = 86.00
Pervious area fraction = 1. 000; Impervious fraction = 0.000
Initial subarea runoff = 12 . 878 (CFS)
Total initial stream area = 4 .450 (Ac. )
Pervious area fraction = 1. 000
81
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
Process from Point/Station 37.000 to Point/Station 38.000
**** NATURAL CHANNEL TIME + SUBAREA FLOW ADDITION **** H2
Top of natural channel elevation = 1447 .700 (Ft.)
End of natural channel elevation = 1428 .700 (Ft. )
Length of natural channel = 240.000 (Ft.)
Estimated mean flow rate at midpoint of channel = 24.959(CFS)
Natural valley channel type used
L.A. County flood control district formula for channel velocity:
Velocity(ft/s) _ (7 + 8 (q(English Units) '.352) (slope^0.5)
Velocity using mean channel flow = 8.95 (Ft/s)
Correction to map slope used on extremely rugged channels with
drops and waterfalls (Plate D-6.2)
Normal channel slope = 0.0792
Corrected/adjusted channel slope = 0.0792
Travel time = 0.45 min. TC = 11.23 min.
Adding area flow to channel
UNDEVELOPED (poor cover) subarea
Runoff Coefficient = 0.845
Decimal fraction soil group A = 0.000
Decimal fraction soil group B = 0.000
Decimal fraction soil group C = 1.000
Decimal fraction soil group D = 0.000
RI index for soil (AMC 2) = 86.00
Pervious area fraction = 1.000; Impervious fraction = 0.000
Rainfall intensity = 3 .353 (In/Hr) for a 100.0 year storm
Subarea runoff = 23 .669 (CFS) for 8.350 (Ac. )
Total runoff = 36.547 (CFS) Total area = 12 .800 (Ac. )
82
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
Process from Point/Station 38.000 to Point/Station 39.000
**** NATURAL CHANNEL TIME + SUBAREA FLOW ADDITION **** H3
Top of natural channel elevation = 1428 .700 (Ft. )
End of natural channel elevation = 1405 .000 (Ft. )
Length of natural channel = 290.000 (Ft. )
Estimated mean flow rate at midpoint of channel = 46.897 (CFS)
Natural valley channel type used
L.A. County flood control district formula for channel velocity:
Velocity(ft/s) = (7 + 8 (q(English Units) ^.352) (slope"0.5)
Velocity using mean channel flow = 10.86 (Ft/s)
Correction to map slope used on extremely rugged channels with
drops and waterfalls (Plate D-6.2)
Normal channel slope = 0.0817
Corrected/adjusted channel slope = 0.0817
Travel time = 0.44 min. TC = 11.67 min.
Adding area flow to channel
UNDEVELOPED (poor cover) subarea
Runoff Coefficient = 0.844
Decimal fraction soil group A = 0.000
Decimal fraction soil group B = 0.000
Decimal fraction soil group C = 1.000
Decimal fraction soil group D = 0.000
RI index for soil (AMC 2) = 86.00
Pervious area fraction = 1.000; Impervious fraction = 0. 000
Rainfall intensity = 3 .292 (In/Hr) for a 100.0 year storm
Subarea runoff = 20.148 (CFS) for 7.250 (Ac. )
Total runoff = 56.696(CFS) Total area = 20.050 (Ac.)
83
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
Process from Point/Station 39. 000 to Point/Station 40.000
**** NATURAL CHANNEL TIME + SUBAREA FLOW ADDITION **** H4
Top of natural channel elevation = 1405.000 (Ft. )
End of natural channel elevation = 1325.000 (Ft. )
Length of natural channel = 760.000 (Ft. )
Estimated mean flow rate at midpoint of channel = 68.855 (CFS)
Natural mountain channel type used
L.A. County flood control district formula for channel velocity:
Velocity = 5.48 (gA.33) (slopeA.492)
Velocity using mean channel flow = 7.26 (Ft/s)
Correction to map slope used on extremely rugged channels with
drops and waterfalls (Plate D-6.2)
Normal channel slope = 0.1053
Corrected/adjusted channel slope = 0 .1037
Travel time = 1.74 min. TC = 13 .42 min.
Adding area flow to channel
UNDEVELOPED (poor cover) subarea
Runoff Coefficient = 0. 841
Decimal fraction soil group A = 0.000
Decimal fraction soil group B = 0.000
Decimal fraction soil group C = 1.000
Decimal fraction soil group D = 0.000
RI index for soil (AMC 2) = 86.00
Pervious area fraction = 1.000; Impervious fraction = 0.000
Rainfall intensity = 3 .079(In/Hr) for a 100.0 year storm
Subarea runoff = 22.259 (CFS) for 8.600 (Ac. )
Total runoff = 78.955 (CFS) Total area = 28.650 (Ac. )
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
Process from Point/Station 40. 000 to Point/Station 40.000
**** SUBAREA FLOW ADDITION **** H5
UNDEVELOPED (poor cover) subarea
Runoff Coefficient = 0.841
Decimal fraction soil group A = 0.000
Decimal fraction soil group B = 0.000
Decimal fraction soil group C = 1.000
Decimal fraction soil group D = 0: 000
RI index for soil (AMC 2) = 86.00
Pervious area fraction = 1.000; Impervious fraction = 0.000
Time of concentration = 13 .42 min.
Rainfall intensity = 3 .079 (In/Hr) for a 100. 0 year storm
Subarea runoff = 16.694 (CFS.) for 6.450 (Ac. )
Total runoff = 95.649(CFS) Total area = 35.100 (Ac.)
)
84
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
Process from Point/Station 40.000 to Point/Station 41.000
**** NATURAL CHANNEL TIME + SUBAREA FLOW ADDITION **** H6
Top of natural channel elevation = 1325 .000 (Ft.)
End of natural channel elevation = 1310. 000 (Ft.)
Length of natural channel = 205.000 (Ft. )
Estimated mean flow rate at midpoint of channel = 101.304 (CFS)
Natural valley channel type used
L.A. County flood control district formula for channel velocity:
Velocity(ft/s) = (7 + 8 (q(English Units) ' .352) (slope'0.5)
Velocity using mean channel flow = 12.89 (Ft/s)
Correction to map slope used on extremely rugged channels with
drops and waterfalls (Plate D-6.2)
Normal channel slope = 0.0732
Corrected/adjusted channel slope = 0.0732
Travel time = 0.27 min. TC = 13 .68 min.
Adding area flow to channel
UNDEVELOPED (poor cover) subarea
Runoff Coefficient = 0.840
Decimal fraction soil group A = 0.000
Decimal fraction soil group B = 0.000
Decimal fraction soil group C = 1.000
Decimal fraction soil group D = 0.000
RI index for soil (AMC 2) = 86.00
Pervious area fraction = 1. 000; Impervious fraction = 0 .000
Rainfall intensity = 3 .050 (In/Hr) for a 100.0 year storm
Subarea runoff = 10.634 (CFS) for 4.150 (Ac. )
Total runoff = 106.283 (CFS) Total area = 39.250 (Ac.)
4100 = 106 . 3 cfs Discharges to San Jacinto River
85
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
Process from Point/Station 1.000 to Point/Station 2 .000
**** INITIAL AREA EVALUATION **** B3
Initial area flow distance = 700 .000 (Ft.)
Top (of initial area) elevation = 1607.100 (Ft. )
Bottom (of initial area) elevation = 1494.600 (Ft. )
Difference in elevation = 112 .500 (Ft. )
Slope = 0.16071 s (percent) = 16.07
TC = k(0.530) * [ (length"3) / (elevation change) ] '0.2
Initial area time of concentration = 10.498 min.
Rainfall intensity = 3.463 (In/Hr) for a 100 .0 year storm
UNDEVELOPED (poor cover) subarea
Runoff Coefficient = 0.847
Decimal fraction soil group A = 0.000
Decimal fraction soil group B = 0.000
Decimal fraction soil group C = 1.000
Decimal fraction soil group D = 0. 000
RI index for soil (AMC 2) = 86.00
Pervious area fraction = 1.000; Impervious fraction = 0.000
Initial subarea runoff = 10 .852 (CFS)
Total initial stream area = 3 .700 (Ac.)
Pervious area fraction = 1.000
Q100 = 10 . 9 cfs Enters project site @ project boundary
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
Process from Point/Station 6.000 to Point/Station 6.100
**** INITIAL AREA EVALUATION **** D3
Initial area flow distance = 865 .000 (Ft.)
Top (of initial area) elevation = 1741.000 (Ft. )
Bottom (of initial area) elevation = 1480.000 (Ft. )
Difference in elevation = 261.000 (Ft.)
Slope = 0.30173 s (percent) = 30.17
TC = k(0.530) * [ (length�3) / (elevation change) 1 ^0.2
Initial area time of concentration = 10.073 min.
Rainfall intensity = 3.533 (In/Hr) for a 100 .0 year storm
UNDEVELOPED (poor cover) subarea
Runoff Coefficient = 0.848
Decimal fraction soil group A = 0.000
Decimal fraction soil group B = 0 .000
Decimal fraction soil group C = 1.000
Decimal fraction soil group D = 0.000
RI index for soil (AMC 2) = 86.00
Pervious area fraction = 1. 000; Impervious fraction = 0.000
Initial subarea runoff = 14 .976 (CFS)
Total initial stream area = 5.000 (Ac.)
Pervious area fraction = 1.000
Q100 = 15. 0 cfs Enters project site @ project boundary
I
86
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
Process from Point/Station 42.100 to Point/Station 42.200
**** INITIAL AREA EVALUATION **** I1
Initial area flow distance = 615.000 (Ft. )
Top (of initial area) elevation = 1655.000 (Ft. )
Bottom (of initial area) elevation = 1524.000 (Ft. )
Difference in elevation = 131. 000 (Ft.)
Slope = 0.21301 s (percent) = 21.30
TC = k(0.530) * [ (length"3) / (elevation change) ] "0.2
Initial area time of concentration = 9.422 min.
Rainfall intensity = 3 .648 (In/Hr) for a 100.0 year storm
UNDEVELOPED (poor cover) subarea
Runoff Coefficient = 0. 849
Decimal fraction soil group A = 0.000
Decimal fraction soil group B = 0 .000
Decimal fraction soil group C = 1.000
Decimal fraction soil group D = 0.000
RI index for soil (AMC 2) = 86.00
Pervious area fraction = 1.000; Impervious fraction = 0.000
Initial subarea runoff = 13.943 (CFS)
Total initial stream area = 4.500 (Ac.)
Pervious area fraction = 1. 000
43.00 = 13 . 9 cfs Enters project site @ project boundary
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
Process from Point/Station 42.200 to Point/Station 42.300
**** NATURAL CHANNEL TIME + SUBAREA FLOW ADDITION **** I2
Top of natural channel elevation = 1524.000 (Ft. )
End of natural channel elevation = 1494.000 (Ft.)
Length of natural channel = 515.000 (Ft.)
Estimated mean flow rate at midpoint of channel = 24 .401(CFS)
Natural valley channel type used
L.A. County flood control district formula for channel velocity:
Velocity(ft/s) = (7 + e (q(English Units) A.352) (slope"0.5)
Velocity using mean channel flow = 7.63 (Ft/s)
Correction to map slope used on extremely rugged channels with
drops and waterfalls (Plate D-6.2)
Normal channel slope = 0. 0583
Corrected/adjusted channel slope = 0.0583
Travel time = 1.12 min. TC = 10.55 min.
Adding area flow to channel
UNDEVELOPED (poor cover) subarea
Runoff Coefficient = 0.847
Decimal fraction soil group A = 0.000
Decimal fraction soil group B = 0.000
Decimal fraction soil group C = 1.000
Decimal fraction soil group D = 0.000
RI index for soil (AMC 2) = 86.00
Pervious area fraction = 1.000; Impervious fraction = 0 . 000
Rainfall intensity = 3 .456 (In/Hr) for a 100.0 year storm
Subarea runoff = 19.752 (CFS) for 6.750 (Ac. )
Total runoff = 33 .695 (CFS) Total area = 11.250 (Ac.)
87
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
Process from Point/Station 42.300 to Point/Station 42 .400
**** NATURAL CHANNEL TIME + SUBAREA FLOW ADDITION **** I3
Top of natural channel elevation = 1494.000 (Ft. )
End of natural channel elevation = 1330.000 (Ft. )
Length of natural channel = 800.000 (Ft. )
Estimated mean flow rate at midpoint of channel = 40.434 (CFS)
Natural mountain channel type used
L.A. County flood control district formula for channel velocity:
Velocity = 5.48 (q~.33) (slope'.492)
Velocity using mean channel flow = 7.59 (Ft/s)
Correction to map slope used on extremely rugged channels with
drops and waterfalls (Plate D-6.2)
Normal channel slope = 0.2050
Corrected/adjusted channel slope = 0.1620
Travel time = 1.76 min. TC = 12.30 min.
Adding area flow to channel
UNDEVELOPED (poor cover) subarea
Runoff Coefficient = 0.843
Decimal fraction soil group A = 0.000
Decimal fraction soil group B = 0.000
Decimal fraction soil group C = 1.000
Decimal fraction soil group D = 0.000
RI index for soil (AMC 2) = 86.00
Pervious area fraction = 1.000; Impervious fraction = 0.000
Rainfall intensity = 3.209 (In/Hr) for a 100.0 year ,storm
Subarea runoff = 12 .174 (CFS) for 4.500 (Ac. )
Total runoff = 45 .868 (CFS) Total area = 15.750 (Ac. )
4ioo = 45 .9 cfs Discharges to San Jacinto River
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
Process from Point/Station 43.100 to Point/Station 43 .200
**** INITIAL AREA EVALUATION **** J
Initial area flow distance = 930.000 (Ft. )
Top (of initial area) elevation = 1550.000 (Ft. )
Bottom (of initial area) elevation = 1330.000 (Ft. )
Difference in elevation = 220. 000 (Ft.)
Slope = 0.23656 s (percent) = 23.66
TC = k(0 .530) * [ (length"3) / (elevation change) ] '0.2
Initial area time of concentration = 10.886 min.
Rainfall intensity = 3 .403 (In/Hr) for a 100.0 year storm
UNDEVELOPED (poor cover) subarea
Runoff Coefficient = 0.846
Decimal fraction soil group A = 0.000
Decimal fraction soil group B = 0.000
Decimal fraction soil group C = 1.000
Decimal fraction soil group D = 0.000
RI index for soil (AMC 2) = 86. 00
Pervious area fraction = 1.000; Impervious fraction = 0.000
Initial subarea runoff = 10.510 (CFS)
Total initial stream area = 3.650 (Ac. )
Pervious area fraction = 1.000
4100 = 10 .5 cfs Discharges to San Jacinto River
I
88
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
Process from Point/Station 44.100 to Point/Station 44.200
**** INITIAL AREA EVALUATION **** K1
Initial area flow distance = 870.000 (Ft.)
Top (of initial area) elevation = 1655.000 (Ft. )
Bottom (of initial area) elevation = 1420.000 (Ft. )
Difference in elevation = 235.000 (Ft.)
Slope = 0.27011 s (percent) = 27.01
TC = k(0.530) * [ (length'3) / (elevation change) 1 '0.2
Initial area time of concentration = 10.322 min.
Rainfall intensity = 3 .491 (In/Hr) for a 100.0 year storm
UNDEVELOPED (poor cover) subarea
Runoff Coefficient = 0.847
Decimal fraction soil group A = 0.000
Decimal fraction soil group B = 0.000
Decimal fraction soil group C = 1.000
Decimal fraction soil group D = 0.000
RI index for soil(AMC 2) = 86.00
Pervious area fraction = 1.000; Impervious fraction = 0 .000
Initial subarea runoff = 10.798 (CFS)
Total initial stream area = 3 .650 (Ac. )
Pervious area fraction = 1.000
4ioo = 10 . 8 cfs Discharges to San Jacinto River
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
Process from Point/Station 44.200 to Point/Station 44 .300
**** NATURAL CHANNEL TIME + SUBAREA FLOW ADDITION **** K2
i Top of natural channel elevation = 1420.000 (Ft. )
End of natural channel elevation = 1330.000 (Ft. )
Length of natural channel = 420.000 (Ft.)
Estimated mean flow rate at midpoint of channel = 16.936 (CFS)
Natural mountain channel type used
L.A. County flood control district formula for channel velocity:
Velocity = 5.48 (q'.33) (slope'.492)
Velocity using mean channel flow = 5.76 (Ft/s)
Correction to map slope used on extremely rugged channels with
drops and waterfalls (Plate D-6.2)
Normal channel slope = 0.2143
Corrected/adjusted channel slope = 0.1657
Travel time = 1.22 min. TC = 11.54 min.
Adding area flow to channel
UNDEVELOPED (poor cover) subarea
Runoff Coefficient = 0 .845
Decimal fraction soil group A = 0 .000
Decimal fraction soil group B = 0.000
Decimal fraction soil group C = 1.000
Decimal fraction soil group D = 0 .000
RI index for soil(AMC 2) = 86.00
Pervious area fraction = 1.000; Impervious fraction = 0 .000
Rainfall intensity = 3 .310 (In/Hr) for a 100.0 year storm
Subarea runoff = 11.601 (CFS) for 4.150 (Ac. )
Total runoff = 22 .398 (CFS) Total area = 7. 800 (Ac. )
I Qioo = 14 .1 cfs Discharges to San Jacinto River
89
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
Process from Point/Station 44.100 to Point/Station 45.000
**** INITIAL AREA EVALUATION **** Ll
Initial area flow distance = 980.000 (Ft. )
Top (of initial area) elevation = 1655.000 (Ft. )
Bottom (of initial area) elevation = 1400.000 (Ft. )
Difference in elevation = 255.000 (Ft.)
Slope = 0.26020 s (percent)= 26.02
TC = k(0.530) * [ (length"3) / (elevation change) ] ^0.2
Initial area time of concentration = 10.907 min.
Rainfall intensity = 3.400 (In/Hr) for a 100.0 year storm
UNDEVELOPED (poor cover) subarea
Runoff Coefficient = 0.846
Decimal fraction soil group A = 0.000
Decimal fraction soil group B = 0.000
Decimal fraction soil group C = 1.000
Decimal fraction soil group D = 0.000
RI index for soil (AMC 2) = 86.00
Pervious area fraction = 1.000; Impervious fraction= 0.000
Initial subarea runoff = 16.396 (CFS)
Total initial stream area = 5.700 (Ac. )
Pervious area fraction = 1.000
4100 = 16 .4 cfs Enters project site @ project boundary
90
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
Process from Point/Station 45.000 to Point/Station 45.100
**** NATURAL CHANNEL TIME + SUBAREA FLOW ADDITION **** L2
Top of natural channel elevation = 1400. 000 (Ft. )
End of natural channel elevation = 1330.000 (Ft.)
Length of natural channel = 285.000 (Ft. )
Estimated mean flow rate at midpoint of channel = 20.136 (CFS)
Natural mountain channel type used
L.A. County flood control district formula for channel velocity:
Velocity = 5.48 (gA.33) (slopeA.492)
Velocity using mean channel flow = 6.32 (Ft/s)
Correction to map slope used on extremely rugged channels with
drops and waterfalls (Plate D-6.2)
Normal channel slope = 0.2456
Corrected/adjusted channel slope = 0.1782
Travel time = 0.75 min. TC = 11.66 min.
Adding area flow to channel
UNDEVELOPED (poor cover) subarea
Runoff Coefficient = 0.844
Decimal fraction soil group A = 0.000
Decimal fraction soil group B = 0.000
Decimal fraction soil group C = 1.000
Decimal fraction soil group D = 0 .000
RI index for soil(AMC 2) = 86.00
Pervious area fraction = 1.000; Impervious fraction = 0.000
Rainfall intensity = 3 .293 (In/Hr) for a 100.0 year storm
Subarea runoff = 7.229 (CFS) for 2.600 (Ac.)
Total runoff = 23 .626 (CFS) Total area = 8.300 (Ac. )
End of computations, total study area = 222 .35 (Ac. )
The following figures may
be used for a unit hydrograph study of the same area.
Area averaged pervious area fraction(Ap) = 0.978
Area averaged RI index number = 85.6
43.00 = 23 . 6 cfs Discharges to San Jacinto River
HYDROLOGY MAP
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