HomeMy WebLinkAboutPD 2024-0012; CARRILLO ELEMENTARY SCHOOL; DRAINAGE STUDY FOR CARRILOO ELEMENTARY SCHOOL; 2024-10-28DRAINAGE STUDY
FOR
Carrillo Elementary School
2875 Poinsettia Lane
Carlsbad, CA 92009
Project ID: PD2024-0012, DWG548-4A, GR2024-0014,
APN: 222-011-11, 222-011-15
Prepared for:
SWS Engineering, Inc.
1635 Lake San Marcos Drive, Suite 200
San Marcos, CA 92078
Engineer:
SWS Engineerina:, Inc.
1635 Lake San Marcos Drive, Suite 200
San Marcos, California 92078
760-7 44-0011
PN: 24-172
I HEREBY DECLARE THAT I AM THE ENGINEER OF WORK FOR THIS PROJECT, THAT I
HAVE EXERCISED RESPONSIBLE CHARGE OVER THE DESIGN OF THE PROJECT AS
DEFINED IN SECTION 6703 OF THE BUSINESS AND PROFESSIONAL CODE, AND THAT
THE DESIGN IN CONSISTENT WITH CURRENT STANDARDS.
I UNDERSTAND THAT THE CHECK OF PROJECT DRAWINGS AND SPECIFICATIONS BY
THE COUNTY OF SAN DIEGO IS ONFINED TO A REVIEW ONLY AND DOES NOT
RELIEVE ME, AS ENGIN RK, OF MY RESPONSIBILITIES FOR THE PROJECT
DESIGN.
Prepare
Date
7/3/2024
8/29/2024
10/28/2024
Comments
1st
2nd
3rd
Associated General Contractors - i - County of San Diego
TABLE OF CONTENTS
1.0 PROJECT DESCRIPTION ................................................................................................... 1
2.0 PURPOSE ............................................................................................................................ 1
3.0 METHODOLOGY ................................................................................................................. 1
4.0 HYDROLOGY ...................................................................................................................... 2
4.1 Pre-Development Condition ..................................................................................... 2
4.2 Post-Development Conditions ................................................................................. 3
4.3 FEMA NFIP ................................................................................................................. 3
5.0 CONCLUSION ..................................................................................................................... 4
APPENDICES
Appendix A – Reference Charts
Table 3-1 – Runoff Coefficients for Urban Areas
Figure 3-1 – Intensity- Duration Design Chart
Soil Hydrologic Groups Map
100 Year Rainfall Event – 6 Hours (P6 Rainfall Isopluvials)
100 Year Rainfall Event – 24 Hours (P24 Rainfall Isopluvials
Appendix B – Pre-Development Hydrology Calculations
Appendix C – Post-Development Hydrology Calculations
Appendix D – Hydraulic Analysis
EXHIBITS
Exhibit “A” – Pre-Development Hydrology Map
Exhibit “B” – Post-Development Hydrology Map
Carrillo Elementary School - 3 - City of Carlsbad
1.0 PROJECT DESCRIPTION
The proposed redevelopment project is a portion of the total 9.76 ac of two parcels that is
located southeast of Poinsettia Lane and southwest of Melrose Drive in the City of Carlsbad,
California. The redevelopment site consists of playground asphalt replacement, ADA/Path of
travel improvement, new artificial turf (impermeable) in place of the existing grass field, and
associated storm drain improvements, including inlets, grates, retaining walls and a treatment
basin. The drainage study area is 4.97 ac, of which 1.35 ac is undisturbed slopes area that the
runoff from them will bypass the disturbed area via proposed storm drain systems into the
existing system located on the south portion of the site. The site has a current and future land
use of Elementary School (Code 6806).
2.0 PURPOSE
The purpose of this study is to determine the peak runoff rates and velocities for the pre-
development and post-development conditions. Comparisons will be made between each
condition to determine the extent of the effects of the proposed improvements on site drainage
and adjacent properties. The adequacy of proposed conveyance facilities will also be
determined.
Carrillo Elementary School - 4 - City of Carlsbad
3.0 METHODOLOGY
The Rational Method as outlined in the San Diego County Hydrology Manual, dated June 2003,
was used to determine the runoff flow rate. The 100-year frequency storm event was analyzed
to determine peak runoff rates discharging the site for both the existing and post-development
condition.
Soil type was determined to be type C from the Soil Hydrologic Groups map, NRCS Web Soil
Survey (see Appendix A). Per the Web Soil Survey, the site has Altamont clay, Las Posas
stony fine sandy loam, and Salinas clay, with slopes ranging from 0-30 percent. The runoff
coefficient “C” was determined by using the closest matching land use category in Table 3-1
(Appendix A). The exhibits have been prepared for the pre-development and post-development
conditions and are attached as Exhibits “A” and “B”.
Runoff coefficients, “C” are summarized below.
Pre-Development: C Coefficient has been selected as follow:
o Pervious area, C = 0.30 (sold type C) basins 1 & 3
o Impervious area, Weighted C = 0.89 (basins 1&2), major basins (User Entry
Option was used)
o Impervious area, C = 0.87 (basins 1-2) initial basins only
o For basins with pervious and impervious areas, the weighted C Coefficient was
used. Since the CivilD software does not have “User Entry Option” for desire C
input, therefore for the initial basins being %100 impervious, the ultimate C
Coefficient 0.87 (for 95% impervious is 0.87, for all soil type) was selected.
Post-Development C Coefficient has been selected as follow:
o Impervious area, C = 0.87 (basins 1-7) initial basins only
o Impervious area, Weighted C = 0.89 (basins 1-7), major basins (User Entry Option
was used)
o For basins with pervious and impervious areas, the weighted C Coefficient was
used. Since the CivilD software does not have “User Entry Option” for desire C
input, therefore for the initial basins being %100 impervious, the ultimate C
Coefficient 0.87 (for 95% impervious is 0.87, for all soil type) was selected.
o Pervious area, C = 0.30 (soil type C) (basins 8 and 9)
4.0 HYDROLOGY
4.1 Pre-Development Conditions
The project is situated on two parcels of total area 9.76 ac, with the project boundary capturing
4.97 acres of the total area. The site slopes range from 0-30%. Runoff from Basin 1 of the
project site will surface flow from the northwest area of the project site in the southeasterly
direction, where it is captured by existing on-site storm drain inlets and routed off-site. Runoff
from Basin 2 located on the southeast of the site will similarly surface flow in the southerly
direction from roof tops into an existing inlet prior to discharging offsite. Runoff from Basin 3 of
the project site will surface flow from the northeast area of the project site in the southerly
Carrillo Elementary School - 5 - City of Carlsbad
direction into existing onsite and then into public storm drain systems before discharging into
San Marcos Creek, then Batiquitos Lagoon and ultimately into the Pacific Ocean.
There is no offsite run-on in the existing condition. A pre-development hydrology map
delineating basin areas, flow paths, and concentration points has been prepared and is attached
to this report as Exhibit “A”. Pre-Development hydrology calculations can be found in Appendix
“B”.
4.2 Post-Development Conditions
The proposed site will consist of the replacement of the existing playground asphalt and grass
field with new asphalt and artificial turf, as well as storm drain improvements such as inlets,
grates, ADA/Path of travel improvement and a bioretention treatment basin. The project site is
situated on two parcels with a total area 9.76 ac, although the drainage study area includes only
4.97 of which 1.35 ac is undisturbed slopes area that the runoff from them will bypass the
disturbed area via proposed storm drain systems into the existing system located on the south
portion of the site. The parcel is located southeast of Poinsettia Lane and southwest of Melrose
Drive in the City of Carlsbad, California.
The proposed site drainage from Basin 1 will surface flow south where it will enter the proposed
on-site storm drain system via proposed catch basins situated along the low-points of the
landscaped slope. The runoff collected from Basin 1 will be routed south, bypassing the
proposed bioretention basin and connecting with the existing storm drain system on the site.
Similarly, proposed site drainage from Basin 2 will surface flow south and enter the proposed
on-site storm drain system via proposed catch basins on the northeastern side of the site.
Runoff from Basin 2 will also be routed towards the existing storm drain system, bypassing the
proposed bioretention basin.
Site drainage from Basins 1-7 will surface flow in the southeasterly direction, where it will enter
into proposed bioretention basin for treatment via existing and proposed inlets and storm drain
systems. After treatment, the drainage from Basins 1-7 will enter the existing storm drain
system on the site, where it will confluence with the untreated flows from Basins 1 and 2. All the
runoff from the site will discharge into San Marcos Creek, then Batiquitos Lagoon and ultimately
into Pacific Ocean.
This drainage analysis has included runoff from the existing rooftop areas within the basins-1-6
that drain into treatment basin in exchange to the runoff discharging from the hard court area,
ADA and path of travel improvement located on the southwest portion of the site.
The proposed project site will have an increase in flow compared to the existing condition due to
the coefficient C. There is no offsite run-on in the post-condition.
A post-development hydrology map delineating basin area, flow paths, concentration points,
and proposed drainage facilities has been prepared and is attached to this report as Exhibit “B”.
Post-development hydrology calculations can be found in Appendix C.
4.2 FEMA NFIP
Per FEMA-NFIP Map (Panel 1055, Map Number 06073C-1055G), the project is located within
Zone X (Areas determined to be outside the 0.2% annual chance floodplain).
Carrillo Elementary School - 6 - City of Carlsbad
5.0 CONCLUSION
The proposed project will change the flow patterns from that of the pre-developed site.
Development of the project site will increase the runoff from the pre-developed condition with
the addition of imperviousness which by implementing the biofiltration basin, the post runoff will
be reduced below the exiting runoff. Table 1 provides a summary of the pre-development areas
and flows. Table 2 provides a summary of the post-development areas and flows. Table 3
provides a comparison between the Q for the pre and post-development conditions. Tables 4
and 5 provides the attenuated Q and pre & post comparison respectfully.
Table 1 – Pre-Development Areas and Flows
Table 2 – Post-Development Areas and Flows
*Construction of one biofiltration basin in Basin 700, will reduce the post Q
from basins 100-700. The Q before attenuation is: 24.19 cfs (See note on the
post calculation)
**Q from the confluence points of all basins 100-900 (node 911) prior to
discharging into proposed 24-inch pipe system (before attenuation)
Table 3 – Increase in Q Between Pre and Post-Condition
Basins Area Pre
(ac)
Pre Q100
(cfs)
100 1.87 11.38
200 0.25 1.69
300 2.85 6.65
Total 4.97 19.72
Basins Area Post
(ac)
Post Q100
(cfs)
100 0.49 3.37*
200 0.22 1.49*
300 0.58 3.98*
400 0.15 0.94*
500 0.09 0.61*
600 0.25 1.69*
700 1.84 12.68*
800 0.75 1.75
900 0.60 1.40
Total 4.97 26.42**
Condition Total Q100
(cfs)
Pre-Development 19.72
Post Development (basins 1-9) 26.42
Increased Q ± (cfs) +6.7
Carrillo Elementary School - 7 - City of Carlsbad
Table 4 –Q after attenuation in Basins 3-4
Table 5 –final Q comparison between pre and post Condition
After the attenuation analysis, the Q discharging from the study area in post condition is
reduced to much lower Q compared to existing area using the biofiltration basin.
The biofiltration basin has a total depth of 2’. In the attenuation analysis, only surface storage of
1.5’ depth (storage above the riser structure to the top of the berm) has been considered.
Storage from the bottom of the surface basin to top of the riser height (0.5’) is provided for the
required water quality treatment control volume (DCV).
In the attenuated analysis, the underground basin layers depth and surface depth have been
modeled for the purpose of using the elevation for the proposed outlet pipe and riser. The
volume for the underground layers as well as the surface storage to top of the riser structure
have been ignored and only used dummy low numbers for the adequate modeling. The result
shows the there is about 0.33’ free board from the 100yr water surface elevation to the top of
the basin’s berm. There is further free board from top of the berm to the downstream system
and project building footprint in case of flooding.
Note: All the elevation used in drainage, attenuation and pipe analysis is based on City of
Carlsbad Datum (NGVD29)
Condition Total Q100
(cfs)
Attenuated Q from basins (1-7) 8.47
Q from Basins (8-9) 3.07
Total Q discharging from
basins (1-7) + bypass basins
(8-9) into proposed 24” pipe
system
11.54
Condition Total Q100
(cfs)
Pre-Development 19.72
Post Development 11.54
Q ± (cfs) -8.18
Carrillo Elementary School - 8 - City of Carlsbad
REFERENCES
CivilDesign Corporation. San Diego County Rational Method. (Software Version 7.7)
County of San Diego Department of Public Works Flood Control Section. San Diego County
Hydrology Manual. (2003)
County of San Diego Department of Public Works Flood Control Section. San Diego County
Drainage Design Manual. (2005)
Hydrologic Soil Group—San Diego County Area, California
Natural Resources
Conservation Service
Web Soil Survey
National Cooperative Soil Survey
5/6/2024
Page 1 of 4
36
6
4
7
0
0
36
6
4
7
3
0
36
6
4
7
6
0
36
6
4
7
9
0
36
6
4
8
2
0
36
6
4
8
5
0
36
6
4
8
8
0
36
6
4
9
1
0
36
6
4
7
0
0
36
6
4
7
3
0
36
6
4
7
6
0
36
6
4
7
9
0
36
6
4
8
2
0
36
6
4
8
5
0
36
6
4
8
8
0
36
6
4
9
1
0
477660 477690 477720 477750 477780 477810 477840 477870 477900 477930 477960 477990
477660 477690 477720 477750 477780 477810 477840 477870 477900 477930 477960 477990
33° 7' 21'' N
11
7
°
1
4
'
2
2
'
'
W
33° 7' 21'' N
11
7
°
1
4
'
9
'
'
W
33° 7' 14'' N
11
7
°
1
4
'
2
2
'
'
W
33° 7' 14'' N
11
7
°
1
4
'
9
'
'
W
N
Map projection: Web Mercator Corner coordinates: WGS84 Edge tics: UTM Zone 11N WGS84
0 50 100 200 300
Feet
0 20 40 80 120
Meters
Map Scale: 1:1,530 if printed on A landscape (11" x 8.5") sheet.
Soil Map may not be valid at this scale.
MAP LEGEND MAP INFORMATION
Area of Interest (AOI)
Area of Interest (AOI)
Soils
Soil Rating Polygons
A
A/D
B
B/D
C
C/D
D
Not rated or not available
Soil Rating Lines
A
A/D
B
B/D
C
C/D
D
Not rated or not available
Soil Rating Points
A
A/D
B
B/D
C
C/D
D
Not rated or not available
Water Features
Streams and Canals
Transportation
Rails
Interstate Highways
US Routes
Major Roads
Local Roads
Background
Aerial Photography
The soil surveys that comprise your AOI were mapped at
1:24,000.
Warning: Soil Map may not be valid at this scale.
Enlargement of maps beyond the scale of mapping can cause
misunderstanding of the detail of mapping and accuracy of soil
line placement. The maps do not show the small areas of
contrasting soils that could have been shown at a more detailed
scale.
Please rely on the bar scale on each map sheet for map
measurements.
Source of Map: Natural Resources Conservation Service
Web Soil Survey URL:
Coordinate System: Web Mercator (EPSG:3857)
Maps from the Web Soil Survey are based on the Web Mercator
projection, which preserves direction and shape but distorts
distance and area. A projection that preserves area, such as the
Albers equal-area conic projection, should be used if more
accurate calculations of distance or area are required.
This product is generated from the USDA-NRCS certified data as
of the version date(s) listed below.
Soil Survey Area: San Diego County Area, California
Survey Area Data: Version 19, Aug 30, 2023
Soil map units are labeled (as space allows) for map scales
1:50,000 or larger.
Date(s) aerial images were photographed: Mar 14, 2022—Mar
17, 2022
The orthophoto or other base map on which the soil lines were
compiled and digitized probably differs from the background
imagery displayed on these maps. As a result, some minor
shifting of map unit boundaries may be evident.
Hydrologic Soil Group—San Diego County Area, California
Natural Resources
Conservation Service
Web Soil Survey
National Cooperative Soil Survey
5/6/2024
Page 2 of 4
Hydrologic Soil Group
Map unit symbol Map unit name Rating Acres in AOI Percent of AOI
AtD Altamont clay, 9 to 15
percent slopes, warm
MAAT, MLRA 20
C 1.0 22.2%
LrE Las Posas stony fine
sandy loam, 9 to 30
percent slopes
C 2.8 61.4%
ScA Salinas clay, 0 to 2
percent slopes
C 0.8 16.4%
Totals for Area of Interest 4.6 100.0%
Description
Hydrologic soil groups are based on estimates of runoff potential. Soils are
assigned to one of four groups according to the rate of water infiltration when the
soils are not protected by vegetation, are thoroughly wet, and receive
precipitation from long-duration storms.
The soils in the United States are assigned to four groups (A, B, C, and D) and
three dual classes (A/D, B/D, and C/D). The groups are defined as follows:
Group A. Soils having a high infiltration rate (low runoff potential) when
thoroughly wet. These consist mainly of deep, well drained to excessively
drained sands or gravelly sands. These soils have a high rate of water
transmission.
Group B. Soils having a moderate infiltration rate when thoroughly wet. These
consist chiefly of moderately deep or deep, moderately well drained or well
drained soils that have moderately fine texture to moderately coarse texture.
These soils have a moderate rate of water transmission.
Group C. Soils having a slow infiltration rate when thoroughly wet. These consist
chiefly of soils having a layer that impedes the downward movement of water or
soils of moderately fine texture or fine texture. These soils have a slow rate of
water transmission.
Group D. Soils having a very slow infiltration rate (high runoff potential) when
thoroughly wet. These consist chiefly of clays that have a high shrink-swell
potential, soils that have a high water table, soils that have a claypan or clay
layer at or near the surface, and soils that are shallow over nearly impervious
material. These soils have a very slow rate of water transmission.
If a soil is assigned to a dual hydrologic group (A/D, B/D, or C/D), the first letter is
for drained areas and the second is for undrained areas. Only the soils that in
their natural condition are in group D are assigned to dual classes.
Hydrologic Soil Group—San Diego County Area, California
Natural Resources
Conservation Service
Web Soil Survey
National Cooperative Soil Survey
5/6/2024
Page 3 of 4
Rating Options
Aggregation Method: Dominant Condition
Component Percent Cutoff: None Specified
Tie-break Rule: Higher
Hydrologic Soil Group—San Diego County Area, California
Natural Resources
Conservation Service
Web Soil Survey
National Cooperative Soil Survey
5/6/2024
Page 4 of 4
t-·····t·--·+····+···+···+·--+---J-l---+--+--l----1---.. ... ... ... ...... . .... ... .. ...... ...... . ......................................... .
! t--t--+--+--+···+···+·····+· .............................. -----··l--+--+--+--+----+--·· ....................................................................... ····-······ '
t·--·--l·······l·······I·····+·--·+····+····+··· •• •••••• • .. ······· ... U) ·· ··· ··· ···· · ...... ··· ··· ······ ······ ··· ··· ······· · ···· ······· .... · ······· ······· · C) · ···ih v m ~ t--+--+-+--+--+-'~ .. ... .. ..... . .... ...... .... . .. .... ....... ..... ....... ... ... ..... ....... ... ····fp···•·····+···+-····+····+····+-·····t---+--t----,1--t--+--+--t ···tb···
~ ························~--····::····
.·~tzrtr
··••:••···••:--••··i·········
f\J\
~r~, ···· +·· .. ;-······'········,··
.. !~--r-----·
County of San Diego
Hydrology Manual
Rainfall lsopluvials
100 Year Rainfall Event - 6 Hours
lsopluvial (inches)
DPW GIS
Depi.!rtmem o.f PubAc. Vl:br.1-i.s:
G(_-.Y)J}K.qJ.W'.: ,1.r,'A1rrr,.:ili.:;,..~, Sw11i.-;r..~
IS
Vi/c Have San Diego Covered!
THIS MAP IS PROVIDED WITHOUT WARRANTY OF ANY KIND, EITHER EXPRESS
OR IMPLIED, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
OF MERCHANTABILITY AND FITNESS FORA PARTICULAR PURPOSE.
Copyright SanGIS. All Rights Reserved.
This products may contain Information from the SANDAG Regional
Information System which cannot be reproduced without the
written permission of SANDAG.
N
~'······+······+···--+····+····+·····+····+·····< .f E
11--1 t~t?0
~1or 17---H-t-rt-H-1 t---t----t+-++++-+~+H-++++µ---1-+----W-+-+---+--4-+-W-+-+-+-+-4++-+-+-+-+__J___j~j_J_-U-llil---l-l-lJ-Ll_J_LLLllllil-Ll-Ll_JJ~LLJ s
This product may contain information which has been reproduced with permission granted by Thomas Brothers Maps.
+----+--+---+---+-1.•-1.1• .................................................................................... 8 .. ··~· . . ..... ....... .... .. ....... ....... ... .... .. ... ... ... ..... ....... ... ... ...... ~ .. 1--+-+--+--J·······I·······,······+·····+ 3 0 3
................................................................................. ··~ .. c:.o •······<······+·····+-····+-·--·+-·····l······+······<·······I·······<·······+ &,···· I--~+-+-+--+--+--<
..... ....... .... .. . ..... ....... .... .. ....... .. .... ...... ~ :;:: . . .. ..... ...... . ....................... ···::t ... l--t--+--+--+---+----+---1-1--+-+--+
Miles
...........................................................
+-••··• ••••• •••••· •••••••••••• ••••••••••••••••···• ····· ····~
··································---········:;:
"I
~~~;~E~J#7~_.,.!_;·+-+-!=~=~:+~~'-f,;L!n~F:!:=.~~=--t-:lc:.,t:::=l, ,:_~+c:_:_.+_:_L·~·L····
·i-t--t--t---nl'~-t---+-+--+----+ ;.:, .. ~ .. r;~:tf; .• ·•·•·•·••.•.• -..~ ::: ... ---
i---i--t--t--t--+-+--+--l-f---i---1-...j.._
! ••••• ••····· ...... ······· ·····+-t--;-,--+-+---,--+-+--l---l---+-.t
·i-----t-+-+--+--+--+---i ................... ······· .............. .
·t--t--,----+---+-+-+--l·•···· ....................... ······ ....
t······i······+···+-+---+--+--+-...... ······ ............. ······ ...... .
······ 3¼1145;H--J--t-t-t-+-+-t-+--+-+-+-++--l--+--l---l--l--+--I----/.....:~
, ....................... ,
.................. ! +-+--+-~-+--+---i .......................... .
■····j·······j······l·······j·····+·····l····+----+--+--+--l .............. ···O·
~
··-f--'>--------''-=i~···· • •••• ••••••• •••• •• •••••• ---t·····+····+···-+·····+····+·· I·· ! ·······1·····'•i••---·••l••···••l••·····l-.....L.....L--L---l__J "'1""
..... io
················~····
~
~
............................
-0----1--~__J___J ......................................................... ..
·l-+--+---"-----'-~--'--............................................. , .............. . County of San Diego
Hydrology Manual
Rainfall lsopluvials
100 Year Rainfall Event -24 Hours
lsopluvial (inches)
DP GIS
Depnrtmi::i.~f of P..Jbi'ic WO.?.-s
-'S~-.:..1.g.r:;.y .. iJl'i;a· /.~~fi:i.rrr:;:1fn.r.1 &y·IJ,:.;:_~~
THIS MAP IS PROVIDED WITHOUT WARRANTY OF ANY KIND, EITHER EXPRESS
OR IMPLIED, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
OF MERCHANTABILITY AND FITNESS FORA PARTICULAR PURPOSE.
Copyright SanGIS. All Rights Reserved.
This products may contain information from the SANDAG Regional Information System which cannot be reproduced without the
written permission of SANDAG.
This product may contain Information which has been reproduced with
permission granted by Thomas Brothers Maps.
Miles
10.0 .... ~~-ir"l"""'l~~,--,.....,.-11-T-l""l""ll"T'T"'l""Ml"T'l"'l"'l"l'tfflTil'l'ffl...,..,M"'l"l-r'T"i!"m"ITTT'l'Tffl'l'fflm"IT-r--t'-r-"1'".,...,.."'1""1'"1"'T'"T"!"T'M'T'l"l"l"IM'l"l"'l"l'IT'
9.QP'illl!l--!"ilir!-...... +""'llr-+'-.&!!-~~t-+-1-HH-++'1-ll+M-++t-~l+t+t+of-lH-+~l+H+++t+t++-tt++i~-+--+-t-+-+-++-++.....+-t-+++1"-t-++li--+1+~
ftO
7.0
6,01--:::i-...+-4-~+--4-.:1111.:-+-.:~--.pi,,ii:::-+=l"'-H.:lllo.:l--?rl.dl+H+¼-f-H+HH+H+HH+H+IH-H#¼-II
2.0
"C' ::I 0 ¢: (I)
(I) ti c:: 1.0
~0.9
·~oJt
fo]
0,6
0.5
0.4
0,3
0,2
0.1,
5 6 7 8 9 10 15 20 30 40 50
Minutes Duration
EQUATION
= 7.44 P6 0~0.645
= Intensity (in/hr)
6-Hour Precipitation (in)
= Duration (min)
2 3 4
Hours
5 6
m ± 0 !:; ,,
it1 Q.
6,o l
5.5 =i-,
5.0 g
4,5 5'
0 4.0 ;;r co
3.5 ~
3.0
2,5
2,0
1.5
1.0
lntensity .. Duratlon Design Chart .. Template
Directions for Application:
(1) From precipitation maps determine 6 hr and 24 hr amounts
for the selected frequency. These maps are included in the
County Hydrology Manual (10, 50, and 100 yr maps included
in the Design and Procedure Manual).
(2) Adjust 6 hr precipitation (If necessary) so that it is within
the range of 45% to 65% of the 24 hr preclprtation (not
applicaple to Desert),
(3) Plot 6 hr precipitation on the right side of the chart
(4) Draw a line through the point parallel to the plotted lines.
(5) This line is the intensity-duration curve for the location
being analyzed.
Application Form:
(a) Selected frequency ___ year
(b) P5 = __ in., Pz4 = __ .::
4
= ___ 0/o(2l
(c) Adjusted P6<2) = __ in.
(d) tx = __ min.
(e) l = __ in./hr.
Note: This chart replaces the lntensity~Duration~Frequency
curves used since 1965.
P6 _____ """""L""'! tJ.5: L 2 t 2.s • ,
OuraUord I )I[!!! I I ! I I
S . .. . .... ...... . 5.27 ! 659 \7,00!~)22 1Q,$1} 1 l86 l 13.ft(UA9 ! 15Jl1
1 2,1? J3.1s 4.24; s.ootEt3e!7. &As; 9.54110.sop1.00112.12
10 1.68 L2.:53; 3.37 t 4.21 15.05 ! 5. 6.74 7.581 BA2 I 9.27 ! 1Ct11
15 UO I U5 ! 2.59; 3.24 13.89 ! 4.54 S.19 5.84 a49 I 7.13 7.78
20 1J)8 U2 2.15; 2.69 3.23!3,n! 4.31 4JIB 5.39 [ 5,93 ! 6.46
as o'"'"" T40·--1.a112.as 2-Ero _tt~n .. 3.1s ____ 4.ao ____ 4.67 ____ s.13J5.af
30 0 U38 2.07 2.49 2.90 3.32 3.73 4.15 4.56 4.98
40 0.69 U)3 1.38 1.72 2.07 2.41 2.16 ~f10 3.45 3.7$ 4.13 .............. so 'o~oo ,roo T19 f49 1Yii ·ioo "fiif --2:ss· "imr ·s:2a s:58
so oJis tHJO 1.as 1 .59 1 .. ae 2.12 2.39 2.65 92 s.1s
90 o. 0.61 0.82 .23 1.43 t.63 1.84 2,04 5 2.45
120 0.34 0.51 t O. 1.021 U9 1.36 1.53 1.87 2.04
150 0.29 0.44f O OJ38j LOS US 1.32 H¼? 1.76
180 (t26 0.3.9!0-52! MS!0.78!0-91! 1.04 ! US 1.44 1.57
""""""'"2il"'o:22.10,33;0Asl o.M!o.s510.16! o.a1+0.se
1
·too I us
1
1.s,r
300 0.19 ,0.28,0.38, OA7,0.00,0.6EL 0.75, 0.85, 0.94, 1.03, US
"""""""300 0.17 l0.25!0.33lOA2T0.50T0,58! 0.67 I CL75 i 0.84 l 0.92 ! UlO
3-1
San Diego County Hydrology Manual
Date: June 2003
Table 3-1
Section:
Page:
RUNOFF COEFFICIENTS FOR URBAN AREAS
Land Use Runoff Coefficient "C"
Soil Type
NRCS Elements Coun Elements % IMPER. A B
Undisturbed Natural Terrain (Natural) Permanent Open Space 0* 0.20 0.25
Low Density Residential (LDR) Residential, 1.0 DU/A or less 10 0.27 0.32
Low Density Residential (LDR) Residential, 2.0 DU/A or less 20 0.34 0.38
Low Density Residential (LDR) Residential, 2.9 DU/A or less 25 0.38 0.41
Medium Density Residential (MDR) Residential, 4.3 DU/A or less 30 0.41 0.45
Medium Density Residential (MDR) Residential, 7.3 DU/A or less 40 0.48 0.51
Medium Density Residential (MDR) Residential, 10.9 DU/A or less 45 0.52 0.54
Medium Density Residential (MDR) Residential, 14.5 DU/A or less 50 0.55 0.58
High Density Residential (HDR) Residential, 24.0 DU/A or less 65 0.66 0.67
High Density Residential (HDR) Residential, 43.0 DU/A or less 80 0.76 0.77
Commercial/Industrial (N. Com) Neighborhood Commercial 80 0.76 0.77
Commercial/Industrial (G. Com) General Commercial 85 0.80 0.80
Commercial/Industrial (O.P. Com) Office Professional/Commercial 90 0.83 0.84
Commercial/Industrial (Limited I.) Limited Industrial 90 0.83 0.84
Commercial/Industrial ( General I.) General Industrial 95 0.87 0.87
3
6 of26
C D
0.30 0.35
0.36 0.41
0.42 0.46
0.45 0.49
0.48 0.52
0.54 0.57
0.57 0.60
0.60 0.63
0.69 0.71
0.78 0.79
0.78 0.79
0.81 0.82
0.84 0.85
0.84 0.85
0.87 0.87
*The values associated with 0% impervious may be used for direct calculation of the runoff coefficient as described in Section 3.1.2 (representing the pervious runoff
coefficient, Cp, for the soil type), or for areas that will remain undisturbed in perpetuity. Justification must be given that the area will remain natural forever ( e.g., the area
is located in Cleveland National Forest).
DU/A= dwelling units per acre
NRCS = National Resources Conservation Service
3-6
San Diego County Rational Hydrology Program
CIVILCADD/CIVILDESIGN Engineering Software,(c)1991-2006 Version 7.7
Rational method hydrology program based on
San Diego County Flood Control Division 2003 hydrology manual
Rational Hydrology Study Date: 10/02/24
-------------------------------------------------------------------
-----
24-172 Pre Development Condition
100-Year Pre Development
Basins 100-300
Onsite Area
-------------------------------------------------------------------
-----
********* Hydrology Study Control Information **********
-------------------------------------------------------------------
-----
Program License Serial Number 6144
-------------------------------------------------------------------
-----
Rational hydrology study storm event year is 100.0
English (in-lb) input data Units used
Map data precipitation entered:
6 hour, precipitation(inches) = 2.950
24 hour precipitation(inches) = 5.250
P6/P24 = 56.2%
San Diego hydrology manual 'C' values used
+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
+++
Process from Point/Station 101.000 to Point/Station
102.000
**** INITIAL AREA EVALUATION ****
___________________________________________________________________
___
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
[UNDISTURBED NATURAL TERRAIN ]
(Permanent Open Space )
Impervious value, Ai = 0.000
Sub-Area C Value = 0.300
Initial subarea total flow distance = 65.000(Ft.)
Highest elevation = 302.980(Ft.)
Lowest elevation = 274.260(Ft.)
Elevation difference = 28.720(Ft.) Slope = 44.185 %
Top of Initial Area Slope adjusted by User to 30.000 %
INITIAL AREA TIME OF CONCENTRATION CALCULATIONS:
The maximum overland flow distance is 100.00 (Ft)
for the top area slope value of 30.00 %, in a development type of
Permanent Open Space
In Accordance With Figure 3-3
Initial Area Time of Concentration = 4.63 minutes
TC = [1.8*(1.1-C)*distance(Ft.)^.5)/(% slope^(1/3)]
TC = [1.8*(1.1-0.3000)*( 100.000^.5)/( 30.000^(1/3)]= 4.63
Calculated TC of 4.634 minutes is less than 5 minutes,
resetting TC to 5.0 minutes for rainfall intensity calculations
Rainfall intensity (I) = 7.772(In/Hr) for a 100.0 year storm
Effective runoff coefficient used for area (Q=KCIA) is C = 0.300
Subarea runoff = 0.793(CFS)
Total initial stream area = 0.340(Ac.)
+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
+++
Process from Point/Station 102.000 to Point/Station
103.000
**** SUBAREA FLOW ADDITION ****
___________________________________________________________________
___
Calculated TC of 4.634 minutes is less than 5 minutes,
resetting TC to 5.0 minutes for rainfall intensity calculations
Rainfall intensity (I) = 7.772(In/Hr) for a 100.0 year storm
User specified 'C' value of 0.890 given for subarea
Time of concentration = 4.63 min.
Rainfall intensity = 7.772(In/Hr) for a 100.0 year storm
Effective runoff coefficient used for total area
(Q=KCIA) is C = 0.783 CA = 1.464
Subarea runoff = 10.584(CFS) for 1.530(Ac.)
Total runoff = 11.377(CFS) Total area = 1.870(Ac.)
+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
+++
Process from Point/Station 201.000 to Point/Station
202.000
**** INITIAL AREA EVALUATION ****
___________________________________________________________________
___
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
[INDUSTRIAL area type ]
(General Industrial )
Impervious value, Ai = 0.950
Sub-Area C Value = 0.870
Initial subarea total flow distance = 185.000(Ft.)
Highest elevation = 269.150(Ft.)
Lowest elevation = 267.160(Ft.)
Elevation difference = 1.990(Ft.) Slope = 1.076 %
Top of Initial Area Slope adjusted by User to 2.000 %
Bottom of Initial Area Slope adjusted by User to 2.000 %
INITIAL AREA TIME OF CONCENTRATION CALCULATIONS:
The maximum overland flow distance is 70.00 (Ft)
for the top area slope value of 2.00 %, in a development type of
General Industrial
In Accordance With Figure 3-3
Initial Area Time of Concentration = 2.75 minutes
TC = [1.8*(1.1-C)*distance(Ft.)^.5)/(% slope^(1/3)]
TC = [1.8*(1.1-0.8700)*( 70.000^.5)/( 2.000^(1/3)]= 2.75
The initial area total distance of 185.00 (Ft.) entered leaves a
remaining distance of 115.00 (Ft.)
Using Figure 3-4, the travel time for this distance is 1.36
minutes
for a distance of 115.00 (Ft.) and a slope of 2.00 %
with an elevation difference of 2.30(Ft.) from the end of the top
area
Tt = [11.9*length(Mi)^3)/(elevation change(Ft.))]^.385 *60(min/hr)
= 1.360 Minutes
Tt=[(11.9*0.0218^3)/( 2.30)]^.385= 1.36
Total initial area Ti = 2.75 minutes from Figure 3-3 formula plus
1.36 minutes from the Figure 3-4 formula = 4.11 minutes
Calculated TC of 4.109 minutes is less than 5 minutes,
resetting TC to 5.0 minutes for rainfall intensity calculations
Rainfall intensity (I) = 7.772(In/Hr) for a 100.0 year storm
Effective runoff coefficient used for area (Q=KCIA) is C = 0.870
Subarea runoff = 1.691(CFS)
Total initial stream area = 0.250(Ac.)
+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
+++
Process from Point/Station 301.000 to Point/Station
302.000
**** INITIAL AREA EVALUATION ****
___________________________________________________________________
___
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
[UNDISTURBED NATURAL TERRAIN ]
(Permanent Open Space )
Impervious value, Ai = 0.000
Sub-Area C Value = 0.300
Initial subarea total flow distance = 79.000(Ft.)
Highest elevation = 311.090(Ft.)
Lowest elevation = 275.110(Ft.)
Elevation difference = 35.980(Ft.) Slope = 45.544 %
Top of Initial Area Slope adjusted by User to 30.000 %
INITIAL AREA TIME OF CONCENTRATION CALCULATIONS:
The maximum overland flow distance is 100.00 (Ft)
for the top area slope value of 30.00 %, in a development type of
Permanent Open Space
In Accordance With Figure 3-3
Initial Area Time of Concentration = 4.63 minutes
TC = [1.8*(1.1-C)*distance(Ft.)^.5)/(% slope^(1/3)]
TC = [1.8*(1.1-0.3000)*( 100.000^.5)/( 30.000^(1/3)]= 4.63
Calculated TC of 4.634 minutes is less than 5 minutes,
resetting TC to 5.0 minutes for rainfall intensity calculations
Rainfall intensity (I) = 7.772(In/Hr) for a 100.0 year storm
Effective runoff coefficient used for area (Q=KCIA) is C = 0.300
Subarea runoff = 1.073(CFS)
Total initial stream area = 0.460(Ac.)
+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
+++
Process from Point/Station 302.000 to Point/Station
303.000
**** SUBAREA FLOW ADDITION ****
___________________________________________________________________
___
Calculated TC of 4.634 minutes is less than 5 minutes,
resetting TC to 5.0 minutes for rainfall intensity calculations
Rainfall intensity (I) = 7.772(In/Hr) for a 100.0 year storm
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
[UNDISTURBED NATURAL TERRAIN ]
(Permanent Open Space )
Impervious value, Ai = 0.000
Sub-Area C Value = 0.300
Time of concentration = 4.63 min.
Rainfall intensity = 7.772(In/Hr) for a 100.0 year storm
Effective runoff coefficient used for total area
(Q=KCIA) is C = 0.300 CA = 0.855
Subarea runoff = 5.573(CFS) for 2.390(Ac.)
Total runoff = 6.645(CFS) Total area = 2.850(Ac.)
End of computations, total study area = 4.970 (Ac.)
San Diego County Rational Hydrology Program
CIVILCADD/CIVILDESIGN Engineering Software,(c)1991-2006 Version 7.7
Rational method hydrology program based on
San Diego County Flood Control Division 2003 hydrology manual
Rational Hydrology Study Date: 10/02/24
-------------------------------------------------------------------
-----
24-172 Post Development Condition
100-year
Basins 100-900
Onsite Area
-------------------------------------------------------------------
-----
********* Hydrology Study Control Information **********
-------------------------------------------------------------------
-----
Program License Serial Number 6144
-------------------------------------------------------------------
-----
Rational hydrology study storm event year is 100.0
English (in-lb) input data Units used
Map data precipitation entered:
6 hour, precipitation(inches) = 2.950
24 hour precipitation(inches) = 5.250
P6/P24 = 56.2%
San Diego hydrology manual 'C' values used
+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
+++
Process from Point/Station 101.000 to Point/Station
102.000
**** INITIAL AREA EVALUATION ****
___________________________________________________________________
___
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
[INDUSTRIAL area type ]
(General Industrial )
Impervious value, Ai = 0.950
Sub-Area C Value = 0.870
Initial subarea total flow distance = 101.000(Ft.)
Highest elevation = 274.020(Ft.)
Lowest elevation = 272.360(Ft.)
Elevation difference = 1.660(Ft.) Slope = 1.644 %
Top of Initial Area Slope adjusted by User to 2.000 %
Bottom of Initial Area Slope adjusted by User to 2.000 %
INITIAL AREA TIME OF CONCENTRATION CALCULATIONS:
The maximum overland flow distance is 70.00 (Ft)
for the top area slope value of 2.00 %, in a development type of
General Industrial
In Accordance With Figure 3-3
Initial Area Time of Concentration = 2.75 minutes
TC = [1.8*(1.1-C)*distance(Ft.)^.5)/(% slope^(1/3)]
TC = [1.8*(1.1-0.8700)*( 70.000^.5)/( 2.000^(1/3)]= 2.75
The initial area total distance of 101.00 (Ft.) entered leaves a
remaining distance of 31.00 (Ft.)
Using Figure 3-4, the travel time for this distance is 0.50
minutes
for a distance of 31.00 (Ft.) and a slope of 2.00 %
with an elevation difference of 0.62(Ft.) from the end of the top
area
Tt = [11.9*length(Mi)^3)/(elevation change(Ft.))]^.385 *60(min/hr)
= 0.496 Minutes
Tt=[(11.9*0.0059^3)/( 0.62)]^.385= 0.50
Total initial area Ti = 2.75 minutes from Figure 3-3 formula plus
0.50 minutes from the Figure 3-4 formula = 3.24 minutes
Calculated TC of 3.245 minutes is less than 5 minutes,
resetting TC to 5.0 minutes for rainfall intensity calculations
Rainfall intensity (I) = 7.772(In/Hr) for a 100.0 year storm
Effective runoff coefficient used for area (Q=KCIA) is C = 0.870
Subarea runoff = 0.676(CFS)
Total initial stream area = 0.100(Ac.)
+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
+++
Process from Point/Station 102.000 to Point/Station
103.000
**** SUBAREA FLOW ADDITION ****
___________________________________________________________________
___
Calculated TC of 3.245 minutes is less than 5 minutes,
resetting TC to 5.0 minutes for rainfall intensity calculations
Rainfall intensity (I) = 7.772(In/Hr) for a 100.0 year storm
User specified 'C' value of 0.890 given for subarea
Time of concentration = 3.24 min.
Rainfall intensity = 7.772(In/Hr) for a 100.0 year storm
Effective runoff coefficient used for total area
(Q=KCIA) is C = 0.886 CA = 0.434
Subarea runoff = 2.698(CFS) for 0.390(Ac.)
Total runoff = 3.374(CFS) Total area = 0.490(Ac.)
+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
+++
Process from Point/Station 103.000 to Point/Station
203.000
**** PIPEFLOW TRAVEL TIME (User specified size) ****
___________________________________________________________________
___
Upstream point/station elevation = 265.940(Ft.)
Downstream point/station elevation = 265.090(Ft.)
Pipe length = 99.00(Ft.) Slope = 0.0086 Manning's N = 0.013
No. of pipes = 1 Required pipe flow = 3.374(CFS)
Given pipe size = 8.00(In.)
NOTE: Normal flow is pressure flow in user selected pipe size.
The approximate hydraulic grade line above the pipe invert is
9.042(Ft.) at the headworks or inlet of the pipe(s)
Pipe friction loss = 7.715(Ft.)
Minor friction loss = 2.176(Ft.) K-factor = 1.50
Pipe flow velocity = 9.67(Ft/s)
Travel time through pipe = 0.17 min.
Time of concentration (TC) = 3.42 min.
+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
+++
Process from Point/Station 103.000 to Point/Station
203.000
**** CONFLUENCE OF MINOR STREAMS ****
___________________________________________________________________
___
Along Main Stream number: 1 in normal stream number 1
Stream flow area = 0.490(Ac.)
Runoff from this stream = 3.374(CFS)
Time of concentration = 3.42 min.
Rainfall intensity = 7.772(In/Hr)
+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
+++
Process from Point/Station 201.000 to Point/Station
202.000
**** INITIAL AREA EVALUATION ****
___________________________________________________________________
___
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
[INDUSTRIAL area type ]
(General Industrial )
Impervious value, Ai = 0.950
Sub-Area C Value = 0.870
Initial subarea total flow distance = 278.000(Ft.)
Highest elevation = 274.020(Ft.)
Lowest elevation = 267.000(Ft.)
Elevation difference = 7.020(Ft.) Slope = 2.525 %
Top of Initial Area Slope adjusted by User to 2.500 %
Bottom of Initial Area Slope adjusted by User to 2.500 %
INITIAL AREA TIME OF CONCENTRATION CALCULATIONS:
The maximum overland flow distance is 80.00 (Ft)
for the top area slope value of 2.50 %, in a development type of
General Industrial
In Accordance With Figure 3-3
Initial Area Time of Concentration = 2.73 minutes
TC = [1.8*(1.1-C)*distance(Ft.)^.5)/(% slope^(1/3)]
TC = [1.8*(1.1-0.8700)*( 80.000^.5)/( 2.500^(1/3)]= 2.73
The initial area total distance of 278.00 (Ft.) entered leaves a
remaining distance of 198.00 (Ft.)
Using Figure 3-4, the travel time for this distance is 1.90
minutes
for a distance of 198.00 (Ft.) and a slope of 2.50 %
with an elevation difference of 4.95(Ft.) from the end of the top
area
Tt = [11.9*length(Mi)^3)/(elevation change(Ft.))]^.385 *60(min/hr)
= 1.896 Minutes
Tt=[(11.9*0.0375^3)/( 4.95)]^.385= 1.90
Total initial area Ti = 2.73 minutes from Figure 3-3 formula plus
1.90 minutes from the Figure 3-4 formula = 4.62 minutes
Calculated TC of 4.624 minutes is less than 5 minutes,
resetting TC to 5.0 minutes for rainfall intensity calculations
Rainfall intensity (I) = 7.772(In/Hr) for a 100.0 year storm
Effective runoff coefficient used for area (Q=KCIA) is C = 0.870
Subarea runoff = 1.488(CFS)
Total initial stream area = 0.220(Ac.)
+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
+++
Process from Point/Station 202.000 to Point/Station
203.000
**** PIPEFLOW TRAVEL TIME (User specified size) ****
___________________________________________________________________
___
Upstream point/station elevation = 266.430(Ft.)
Downstream point/station elevation = 265.090(Ft.)
Pipe length = 16.00(Ft.) Slope = 0.0838 Manning's N = 0.013
No. of pipes = 1 Required pipe flow = 1.488(CFS)
Given pipe size = 8.00(In.)
Calculated individual pipe flow = 1.488(CFS)
Normal flow depth in pipe = 3.64(In.)
Flow top width inside pipe = 7.97(In.)
Critical Depth = 6.84(In.)
Pipe flow velocity = 9.62(Ft/s)
Travel time through pipe = 0.03 min.
Time of concentration (TC) = 4.65 min.
+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
+++
Process from Point/Station 203.000 to Point/Station
203.000
**** CONFLUENCE OF MINOR STREAMS ****
___________________________________________________________________
___
Along Main Stream number: 1 in normal stream number 2
Stream flow area = 0.220(Ac.)
Runoff from this stream = 1.488(CFS)
Time of concentration = 4.65 min.
Rainfall intensity = 7.772(In/Hr)
Summary of stream data:
Stream Flow rate TC Rainfall Intensity
No. (CFS) (min) (In/Hr)
1 3.374 3.42 7.772
2 1.488 4.65 7.772
Qmax(1) =
1.000 * 1.000 * 3.374) +
1.000 * 0.734 * 1.488) + = 4.466
Qmax(2) =
1.000 * 1.000 * 3.374) +
1.000 * 1.000 * 1.488) + = 4.862
Total of 2 streams to confluence:
Flow rates before confluence point:
3.374 1.488
Maximum flow rates at confluence using above data:
4.466 4.862
Area of streams before confluence:
0.490 0.220
Results of confluence:
Total flow rate = 4.862(CFS)
Time of concentration = 4.652 min.
Effective stream area after confluence = 0.710(Ac.)
+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
+++
Process from Point/Station 203.000 to Point/Station
304.000
**** PIPEFLOW TRAVEL TIME (User specified size) ****
___________________________________________________________________
___
Upstream point/station elevation = 265.090(Ft.)
Downstream point/station elevation = 265.080(Ft.)
Pipe length = 127.00(Ft.) Slope = 0.0001 Manning's N = 0.013
No. of pipes = 1 Required pipe flow = 4.862(CFS)
Given pipe size = 8.00(In.)
NOTE: Normal flow is pressure flow in user selected pipe size.
The approximate hydraulic grade line above the pipe invert is
25.058(Ft.) at the headworks or inlet of the pipe(s)
Pipe friction loss = 20.550(Ft.)
Minor friction loss = 4.518(Ft.) K-factor = 1.50
Pipe flow velocity = 13.93(Ft/s)
Travel time through pipe = 0.15 min.
Time of concentration (TC) = 4.80 min.
+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
+++
Process from Point/Station 203.000 to Point/Station
304.000
**** CONFLUENCE OF MINOR STREAMS ****
___________________________________________________________________
___
Along Main Stream number: 1 in normal stream number 1
Stream flow area = 0.710(Ac.)
Runoff from this stream = 4.862(CFS)
Time of concentration = 4.80 min.
Rainfall intensity = 7.772(In/Hr)
+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
+++
Process from Point/Station 301.000 to Point/Station
302.000
**** INITIAL AREA EVALUATION ****
___________________________________________________________________
___
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
[INDUSTRIAL area type ]
(General Industrial )
Impervious value, Ai = 0.950
Sub-Area C Value = 0.870
Initial subarea total flow distance = 100.000(Ft.)
Highest elevation = 274.000(Ft.)
Lowest elevation = 272.160(Ft.)
Elevation difference = 1.840(Ft.) Slope = 1.840 %
Top of Initial Area Slope adjusted by User to 2.000 %
Bottom of Initial Area Slope adjusted by User to 2.000 %
INITIAL AREA TIME OF CONCENTRATION CALCULATIONS:
The maximum overland flow distance is 70.00 (Ft)
for the top area slope value of 2.00 %, in a development type of
General Industrial
In Accordance With Figure 3-3
Initial Area Time of Concentration = 2.75 minutes
TC = [1.8*(1.1-C)*distance(Ft.)^.5)/(% slope^(1/3)]
TC = [1.8*(1.1-0.8700)*( 70.000^.5)/( 2.000^(1/3)]= 2.75
The initial area total distance of 100.00 (Ft.) entered leaves a
remaining distance of 30.00 (Ft.)
Using Figure 3-4, the travel time for this distance is 0.48
minutes
for a distance of 30.00 (Ft.) and a slope of 2.00 %
with an elevation difference of 0.60(Ft.) from the end of the top
area
Tt = [11.9*length(Mi)^3)/(elevation change(Ft.))]^.385 *60(min/hr)
= 0.483 Minutes
Tt=[(11.9*0.0057^3)/( 0.60)]^.385= 0.48
Total initial area Ti = 2.75 minutes from Figure 3-3 formula plus
0.48 minutes from the Figure 3-4 formula = 3.23 minutes
Calculated TC of 3.232 minutes is less than 5 minutes,
resetting TC to 5.0 minutes for rainfall intensity calculations
Rainfall intensity (I) = 7.772(In/Hr) for a 100.0 year storm
Effective runoff coefficient used for area (Q=KCIA) is C = 0.870
Subarea runoff = 1.352(CFS)
Total initial stream area = 0.200(Ac.)
+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
+++
Process from Point/Station 302.000 to Point/Station
303.000
**** SUBAREA FLOW ADDITION ****
___________________________________________________________________
___
Calculated TC of 3.232 minutes is less than 5 minutes,
resetting TC to 5.0 minutes for rainfall intensity calculations
Rainfall intensity (I) = 7.772(In/Hr) for a 100.0 year storm
User specified 'C' value of 0.890 given for subarea
Time of concentration = 3.23 min.
Rainfall intensity = 7.772(In/Hr) for a 100.0 year storm
Effective runoff coefficient used for total area
(Q=KCIA) is C = 0.883 CA = 0.512
Subarea runoff = 2.629(CFS) for 0.380(Ac.)
Total runoff = 3.981(CFS) Total area = 0.580(Ac.)
+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
+++
Process from Point/Station 303.000 to Point/Station
304.000
**** PIPEFLOW TRAVEL TIME (User specified size) ****
___________________________________________________________________
___
Upstream point/station elevation = 265.260(Ft.)
Downstream point/station elevation = 265.080(Ft.)
Pipe length = 36.00(Ft.) Slope = 0.0050 Manning's N = 0.013
No. of pipes = 1 Required pipe flow = 3.981(CFS)
Given pipe size = 8.00(In.)
NOTE: Normal flow is pressure flow in user selected pipe size.
The approximate hydraulic grade line above the pipe invert is
6.756(Ft.) at the headworks or inlet of the pipe(s)
Pipe friction loss = 3.906(Ft.)
Minor friction loss = 3.030(Ft.) K-factor = 1.50
Pipe flow velocity = 11.40(Ft/s)
Travel time through pipe = 0.05 min.
Time of concentration (TC) = 3.28 min.
+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
+++
Process from Point/Station 304.000 to Point/Station
304.000
**** CONFLUENCE OF MINOR STREAMS ****
___________________________________________________________________
___
Along Main Stream number: 1 in normal stream number 2
Stream flow area = 0.580(Ac.)
Runoff from this stream = 3.981(CFS)
Time of concentration = 3.28 min.
Rainfall intensity = 7.772(In/Hr)
Summary of stream data:
Stream Flow rate TC Rainfall Intensity
No. (CFS) (min) (In/Hr)
1 4.862 4.80 7.772
2 3.981 3.28 7.772
Qmax(1) =
1.000 * 1.000 * 4.862) +
1.000 * 1.000 * 3.981) + = 8.843
Qmax(2) =
1.000 * 0.684 * 4.862) +
1.000 * 1.000 * 3.981) + = 7.305
Total of 2 streams to confluence:
Flow rates before confluence point:
4.862 3.981
Maximum flow rates at confluence using above data:
8.843 7.305
Area of streams before confluence:
0.710 0.580
Results of confluence:
Total flow rate = 8.843(CFS)
Time of concentration = 4.804 min.
Effective stream area after confluence = 1.290(Ac.)
+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
+++
Process from Point/Station 304.000 to Point/Station
504.000
**** CONFLUENCE OF MAIN STREAMS ****
___________________________________________________________________
___
The following data inside Main Stream is listed:
In Main Stream number: 1
Stream flow area = 1.290(Ac.)
Runoff from this stream = 8.843(CFS)
Time of concentration = 4.80 min.
Rainfall intensity = 7.772(In/Hr)
Program is now starting with Main Stream No. 2
+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
+++
Process from Point/Station 401.000 to Point/Station
402.000
**** INITIAL AREA EVALUATION ****
___________________________________________________________________
___
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
[INDUSTRIAL area type ]
(General Industrial )
Impervious value, Ai = 0.950
Sub-Area C Value = 0.870
Initial subarea total flow distance = 229.000(Ft.)
Highest elevation = 274.630(Ft.)
Lowest elevation = 273.870(Ft.)
Elevation difference = 0.760(Ft.) Slope = 0.332 %
Top of Initial Area Slope adjusted by User to 1.000 %
Bottom of Initial Area Slope adjusted by User to 1.000 %
INITIAL AREA TIME OF CONCENTRATION CALCULATIONS:
The maximum overland flow distance is 60.00 (Ft)
for the top area slope value of 1.00 %, in a development type of
General Industrial
In Accordance With Figure 3-3
Initial Area Time of Concentration = 3.21 minutes
TC = [1.8*(1.1-C)*distance(Ft.)^.5)/(% slope^(1/3)]
TC = [1.8*(1.1-0.8700)*( 60.000^.5)/( 1.000^(1/3)]= 3.21
The initial area total distance of 229.00 (Ft.) entered leaves a
remaining distance of 169.00 (Ft.)
Using Figure 3-4, the travel time for this distance is 2.39
minutes
for a distance of 169.00 (Ft.) and a slope of 1.00 %
with an elevation difference of 1.69(Ft.) from the end of the top
area
Tt = [11.9*length(Mi)^3)/(elevation change(Ft.))]^.385 *60(min/hr)
= 2.388 Minutes
Tt=[(11.9*0.0320^3)/( 1.69)]^.385= 2.39
Total initial area Ti = 3.21 minutes from Figure 3-3 formula plus
2.39 minutes from the Figure 3-4 formula = 5.60 minutes
Rainfall intensity (I) = 7.229(In/Hr) for a 100.0 year storm
Effective runoff coefficient used for area (Q=KCIA) is C = 0.870
Subarea runoff = 0.943(CFS)
Total initial stream area = 0.150(Ac.)
+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
+++
Process from Point/Station 402.000 to Point/Station
503.000
**** PIPEFLOW TRAVEL TIME (User specified size) ****
___________________________________________________________________
___
Upstream point/station elevation = 268.740(Ft.)
Downstream point/station elevation = 267.900(Ft.)
Pipe length = 168.00(Ft.) Slope = 0.0050 Manning's N = 0.013
No. of pipes = 1 Required pipe flow = 0.943(CFS)
Given pipe size = 8.00(In.)
NOTE: Normal flow is pressure flow in user selected pipe size.
The approximate hydraulic grade line above the pipe invert is
0.354(Ft.) at the headworks or inlet of the pipe(s)
Pipe friction loss = 1.023(Ft.)
Minor friction loss = 0.170(Ft.) K-factor = 1.50
Pipe flow velocity = 2.70(Ft/s)
Travel time through pipe = 1.04 min.
Time of concentration (TC) = 6.63 min.
+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
+++
Process from Point/Station 402.000 to Point/Station
503.000
**** CONFLUENCE OF MINOR STREAMS ****
___________________________________________________________________
___
Along Main Stream number: 2 in normal stream number 1
Stream flow area = 0.150(Ac.)
Runoff from this stream = 0.943(CFS)
Time of concentration = 6.63 min.
Rainfall intensity = 6.478(In/Hr)
+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
+++
Process from Point/Station 501.000 to Point/Station
502.000
**** INITIAL AREA EVALUATION ****
___________________________________________________________________
___
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
[INDUSTRIAL area type ]
(General Industrial )
Impervious value, Ai = 0.950
Sub-Area C Value = 0.870
Initial subarea total flow distance = 102.000(Ft.)
Highest elevation = 272.520(Ft.)
Lowest elevation = 272.170(Ft.)
Elevation difference = 0.350(Ft.) Slope = 0.343 %
Top of Initial Area Slope adjusted by User to 1.000 %
Bottom of Initial Area Slope adjusted by User to 1.000 %
INITIAL AREA TIME OF CONCENTRATION CALCULATIONS:
The maximum overland flow distance is 60.00 (Ft)
for the top area slope value of 1.00 %, in a development type of
General Industrial
In Accordance With Figure 3-3
Initial Area Time of Concentration = 3.21 minutes
TC = [1.8*(1.1-C)*distance(Ft.)^.5)/(% slope^(1/3)]
TC = [1.8*(1.1-0.8700)*( 60.000^.5)/( 1.000^(1/3)]= 3.21
The initial area total distance of 102.00 (Ft.) entered leaves a
remaining distance of 42.00 (Ft.)
Using Figure 3-4, the travel time for this distance is 0.82
minutes
for a distance of 42.00 (Ft.) and a slope of 1.00 %
with an elevation difference of 0.42(Ft.) from the end of the top
area
Tt = [11.9*length(Mi)^3)/(elevation change(Ft.))]^.385 *60(min/hr)
= 0.818 Minutes
Tt=[(11.9*0.0080^3)/( 0.42)]^.385= 0.82
Total initial area Ti = 3.21 minutes from Figure 3-3 formula plus
0.82 minutes from the Figure 3-4 formula = 4.02 minutes
Calculated TC of 4.024 minutes is less than 5 minutes,
resetting TC to 5.0 minutes for rainfall intensity calculations
Rainfall intensity (I) = 7.772(In/Hr) for a 100.0 year storm
Effective runoff coefficient used for area (Q=KCIA) is C = 0.870
Subarea runoff = 0.609(CFS)
Total initial stream area = 0.090(Ac.)
+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
+++
Process from Point/Station 502.000 to Point/Station
503.000
**** PIPEFLOW TRAVEL TIME (User specified size) ****
___________________________________________________________________
___
Upstream point/station elevation = 268.600(Ft.)
Downstream point/station elevation = 267.900(Ft.)
Pipe length = 50.00(Ft.) Slope = 0.0140 Manning's N = 0.013
No. of pipes = 1 Required pipe flow = 0.609(CFS)
Given pipe size = 8.00(In.)
Calculated individual pipe flow = 0.609(CFS)
Normal flow depth in pipe = 3.64(In.)
Flow top width inside pipe = 7.97(In.)
Critical Depth = 4.41(In.)
Pipe flow velocity = 3.93(Ft/s)
Travel time through pipe = 0.21 min.
Time of concentration (TC) = 4.24 min.
+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
+++
Process from Point/Station 503.000 to Point/Station
503.000
**** CONFLUENCE OF MINOR STREAMS ****
___________________________________________________________________
___
Along Main Stream number: 2 in normal stream number 2
Stream flow area = 0.090(Ac.)
Runoff from this stream = 0.609(CFS)
Time of concentration = 4.24 min.
Rainfall intensity = 7.772(In/Hr)
Summary of stream data:
Stream Flow rate TC Rainfall Intensity
No. (CFS) (min) (In/Hr)
1 0.943 6.63 6.478
2 0.609 4.24 7.772
Qmax(1) =
1.000 * 1.000 * 0.943) +
0.834 * 1.000 * 0.609) + = 1.451
Qmax(2) =
1.000 * 0.639 * 0.943) +
1.000 * 1.000 * 0.609) + = 1.211
Total of 2 streams to confluence:
Flow rates before confluence point:
0.943 0.609
Maximum flow rates at confluence using above data:
1.451 1.211
Area of streams before confluence:
0.150 0.090
Results of confluence:
Total flow rate = 1.451(CFS)
Time of concentration = 6.631 min.
Effective stream area after confluence = 0.240(Ac.)
+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
+++
Process from Point/Station 503.000 to Point/Station
504.000
**** PIPEFLOW TRAVEL TIME (User specified size) ****
___________________________________________________________________
___
Upstream point/station elevation = 268.350(Ft.)
Downstream point/station elevation = 264.860(Ft.)
Pipe length = 172.00(Ft.) Slope = 0.0203 Manning's N = 0.013
No. of pipes = 1 Required pipe flow = 1.451(CFS)
Given pipe size = 8.00(In.)
Calculated individual pipe flow = 1.451(CFS)
Normal flow depth in pipe = 5.63(In.)
Flow top width inside pipe = 7.31(In.)
Critical Depth = 6.78(In.)
Pipe flow velocity = 5.53(Ft/s)
Travel time through pipe = 0.52 min.
Time of concentration (TC) = 7.15 min.
+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
+++
Process from Point/Station 504.000 to Point/Station
504.000
**** CONFLUENCE OF MAIN STREAMS ****
___________________________________________________________________
___
The following data inside Main Stream is listed:
In Main Stream number: 2
Stream flow area = 0.240(Ac.)
Runoff from this stream = 1.451(CFS)
Time of concentration = 7.15 min.
Rainfall intensity = 6.171(In/Hr)
Summary of stream data:
Stream Flow rate TC Rainfall Intensity
No. (CFS) (min) (In/Hr)
1 8.843 4.80 7.772
2 1.451 7.15 6.171
Qmax(1) =
1.000 * 1.000 * 8.843) +
1.000 * 0.672 * 1.451) + = 9.817
Qmax(2) =
0.794 * 1.000 * 8.843) +
1.000 * 1.000 * 1.451) + = 8.472
Total of 2 main streams to confluence:
Flow rates before confluence point:
8.843 1.451
Maximum flow rates at confluence using above data:
9.817 8.472
Area of streams before confluence:
1.290 0.240
Results of confluence:
Total flow rate = 9.817(CFS)
Time of concentration = 4.804 min.
Effective stream area after confluence = 1.530(Ac.)
+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
+++
Process from Point/Station 504.000 to Point/Station
703.000
**** PIPEFLOW TRAVEL TIME (User specified size) ****
___________________________________________________________________
___
Upstream point/station elevation = 264.860(Ft.)
Downstream point/station elevation = 259.540(Ft.)
Pipe length = 151.00(Ft.) Slope = 0.0352 Manning's N = 0.013
No. of pipes = 1 Required pipe flow = 9.817(CFS)
Given pipe size = 10.00(In.)
NOTE: Normal flow is pressure flow in user selected pipe size.
The approximate hydraulic grade line above the pipe invert is
32.534(Ft.) at the headworks or inlet of the pipe(s)
Pipe friction loss = 30.307(Ft.)
Minor friction loss = 7.547(Ft.) K-factor = 1.50
Pipe flow velocity = 18.00(Ft/s)
Travel time through pipe = 0.14 min.
Time of concentration (TC) = 4.94 min.
+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
+++
Process from Point/Station 504.000 to Point/Station
703.000
**** CONFLUENCE OF MINOR STREAMS ****
___________________________________________________________________
___
Along Main Stream number: 1 in normal stream number 1
Stream flow area = 1.530(Ac.)
Runoff from this stream = 9.817(CFS)
Time of concentration = 4.94 min.
Rainfall intensity = 7.772(In/Hr)
+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
+++
Process from Point/Station 601.000 to Point/Station
602.000
**** INITIAL AREA EVALUATION ****
___________________________________________________________________
___
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
[INDUSTRIAL area type ]
(General Industrial )
Impervious value, Ai = 0.950
Sub-Area C Value = 0.870
Initial subarea total flow distance = 185.000(Ft.)
Highest elevation = 269.150(Ft.)
Lowest elevation = 267.160(Ft.)
Elevation difference = 1.990(Ft.) Slope = 1.076 %
Top of Initial Area Slope adjusted by User to 2.000 %
Bottom of Initial Area Slope adjusted by User to 2.000 %
INITIAL AREA TIME OF CONCENTRATION CALCULATIONS:
The maximum overland flow distance is 70.00 (Ft)
for the top area slope value of 2.00 %, in a development type of
General Industrial
In Accordance With Figure 3-3
Initial Area Time of Concentration = 2.75 minutes
TC = [1.8*(1.1-C)*distance(Ft.)^.5)/(% slope^(1/3)]
TC = [1.8*(1.1-0.8700)*( 70.000^.5)/( 2.000^(1/3)]= 2.75
The initial area total distance of 185.00 (Ft.) entered leaves a
remaining distance of 115.00 (Ft.)
Using Figure 3-4, the travel time for this distance is 1.36
minutes
for a distance of 115.00 (Ft.) and a slope of 2.00 %
with an elevation difference of 2.30(Ft.) from the end of the top
area
Tt = [11.9*length(Mi)^3)/(elevation change(Ft.))]^.385 *60(min/hr)
= 1.360 Minutes
Tt=[(11.9*0.0218^3)/( 2.30)]^.385= 1.36
Total initial area Ti = 2.75 minutes from Figure 3-3 formula plus
1.36 minutes from the Figure 3-4 formula = 4.11 minutes
Calculated TC of 4.109 minutes is less than 5 minutes,
resetting TC to 5.0 minutes for rainfall intensity calculations
Rainfall intensity (I) = 7.772(In/Hr) for a 100.0 year storm
Effective runoff coefficient used for area (Q=KCIA) is C = 0.870
Subarea runoff = 1.691(CFS)
Total initial stream area = 0.250(Ac.)
+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
+++
Process from Point/Station 602.000 to Point/Station
703.000
**** PIPEFLOW TRAVEL TIME (User specified size) ****
___________________________________________________________________
___
Upstream point/station elevation = 264.740(Ft.)
Downstream point/station elevation = 259.540(Ft.)
Pipe length = 124.00(Ft.) Slope = 0.0419 Manning's N = 0.013
No. of pipes = 1 Required pipe flow = 1.691(CFS)
Given pipe size = 8.00(In.)
Calculated individual pipe flow = 1.691(CFS)
Normal flow depth in pipe = 4.85(In.)
Flow top width inside pipe = 7.82(In.)
Critical Depth = 7.17(In.)
Pipe flow velocity = 7.63(Ft/s)
Travel time through pipe = 0.27 min.
Time of concentration (TC) = 4.38 min.
+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
+++
Process from Point/Station 602.000 to Point/Station
703.000
**** CONFLUENCE OF MINOR STREAMS ****
___________________________________________________________________
___
Along Main Stream number: 1 in normal stream number 2
Stream flow area = 0.250(Ac.)
Runoff from this stream = 1.691(CFS)
Time of concentration = 4.38 min.
Rainfall intensity = 7.772(In/Hr)
+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
+++
Process from Point/Station 701.000 to Point/Station
702.000
**** INITIAL AREA EVALUATION ****
___________________________________________________________________
___
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
[INDUSTRIAL area type ]
(General Industrial )
Impervious value, Ai = 0.950
Sub-Area C Value = 0.870
Initial subarea total flow distance = 69.000(Ft.)
Highest elevation = 275.090(Ft.)
Lowest elevation = 273.410(Ft.)
Elevation difference = 1.680(Ft.) Slope = 2.435 %
Top of Initial Area Slope adjusted by User to 2.000 %
INITIAL AREA TIME OF CONCENTRATION CALCULATIONS:
The maximum overland flow distance is 70.00 (Ft)
for the top area slope value of 2.00 %, in a development type of
General Industrial
In Accordance With Figure 3-3
Initial Area Time of Concentration = 2.75 minutes
TC = [1.8*(1.1-C)*distance(Ft.)^.5)/(% slope^(1/3)]
TC = [1.8*(1.1-0.8700)*( 70.000^.5)/( 2.000^(1/3)]= 2.75
Calculated TC of 2.749 minutes is less than 5 minutes,
resetting TC to 5.0 minutes for rainfall intensity calculations
Rainfall intensity (I) = 7.772(In/Hr) for a 100.0 year storm
Effective runoff coefficient used for area (Q=KCIA) is C = 0.870
Subarea runoff = 2.029(CFS)
Total initial stream area = 0.300(Ac.)
+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
+++
Process from Point/Station 702.000 to Point/Station
703.000
**** SUBAREA FLOW ADDITION ****
___________________________________________________________________
___
Calculated TC of 2.749 minutes is less than 5 minutes,
resetting TC to 5.0 minutes for rainfall intensity calculations
Rainfall intensity (I) = 7.772(In/Hr) for a 100.0 year storm
User specified 'C' value of 0.890 given for subarea
Time of concentration = 2.75 min.
Rainfall intensity = 7.772(In/Hr) for a 100.0 year storm
Effective runoff coefficient used for total area
(Q=KCIA) is C = 0.887 CA = 1.632
Subarea runoff = 10.653(CFS) for 1.540(Ac.)
Total runoff = 12.682(CFS) Total area = 1.840(Ac.)
+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
+++
Process from Point/Station 703.000 to Point/Station
703.000
**** CONFLUENCE OF MINOR STREAMS ****
___________________________________________________________________
___
Along Main Stream number: 1 in normal stream number 3
Stream flow area = 1.840(Ac.)
Runoff from this stream = 12.682(CFS)
Time of concentration = 2.75 min.
Rainfall intensity = 7.772(In/Hr)
Summary of stream data:
Stream Flow rate TC Rainfall Intensity
No. (CFS) (min) (In/Hr)
1 9.817 4.94 7.772
2 1.691 4.38 7.772
3 12.682 2.75 7.772
Qmax(1) =
1.000 * 1.000 * 9.817) +
1.000 * 1.000 * 1.691) +
1.000 * 1.000 * 12.682) + = 24.190
Qmax(2) =
1.000 * 0.886 * 9.817) +
1.000 * 1.000 * 1.691) +
1.000 * 1.000 * 12.682) + = 23.069
Qmax(3) =
1.000 * 0.556 * 9.817) +
1.000 * 0.628 * 1.691) +
1.000 * 1.000 * 12.682) + = 19.202
Total of 3 streams to confluence:
Flow rates before confluence point:
9.817 1.691 12.682
Maximum flow rates at confluence using above data:
24.190 23.069 19.202
Area of streams before confluence:
1.530 0.250 1.840
Results of confluence:
Total flow rate = 24.190(CFS)
Time of concentration = 4.944 min.
Effective stream area after confluence = 3.620(Ac.)
+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
+++
Process from Point/Station 703.000 to Point/Station
911.000
**** PIPEFLOW TRAVEL TIME (User specified size) ****
___________________________________________________________________
___
Upstream point/station elevation = 259.540(Ft.)
Downstream point/station elevation = 259.030(Ft.)
Pipe length = 30.00(Ft.) Slope = 0.0170 Manning's N = 0.013
No. of pipes = 1 Required pipe flow = 24.190(CFS)
Given pipe size = 24.00(In.)
Calculated individual pipe flow = 24.190(CFS)
Normal flow depth in pipe = 16.55(In.)
Flow top width inside pipe = 22.21(In.)
Critical Depth = 20.87(In.)
Pipe flow velocity = 10.48(Ft/s)
Travel time through pipe = 0.05 min.
Time of concentration (TC) = 4.99 min.
+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
+++
Process from Point/Station 703.000 to Point/Station
911.000
**** CONFLUENCE OF MAIN STREAMS ****
___________________________________________________________________
___
The following data inside Main Stream is listed:
In Main Stream number: 1
Stream flow area = 3.620(Ac.)
Runoff from this stream = 24.190(CFS)
Time of concentration = 4.99 min.
Rainfall intensity = 7.772(In/Hr)
Program is now starting with Main Stream No. 2
+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
+++
Process from Point/Station 801.000 to Point/Station
802.000
**** INITIAL AREA EVALUATION ****
___________________________________________________________________
___
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
[UNDISTURBED NATURAL TERRAIN ]
(Permanent Open Space )
Impervious value, Ai = 0.000
Sub-Area C Value = 0.300
Initial subarea total flow distance = 76.000(Ft.)
Highest elevation = 311.050(Ft.)
Lowest elevation = 275.190(Ft.)
Elevation difference = 35.860(Ft.) Slope = 47.184 %
Top of Initial Area Slope adjusted by User to 30.000 %
INITIAL AREA TIME OF CONCENTRATION CALCULATIONS:
The maximum overland flow distance is 100.00 (Ft)
for the top area slope value of 30.00 %, in a development type of
Permanent Open Space
In Accordance With Figure 3-3
Initial Area Time of Concentration = 4.63 minutes
TC = [1.8*(1.1-C)*distance(Ft.)^.5)/(% slope^(1/3)]
TC = [1.8*(1.1-0.3000)*( 100.000^.5)/( 30.000^(1/3)]= 4.63
Calculated TC of 4.634 minutes is less than 5 minutes,
resetting TC to 5.0 minutes for rainfall intensity calculations
Rainfall intensity (I) = 7.772(In/Hr) for a 100.0 year storm
Effective runoff coefficient used for area (Q=KCIA) is C = 0.300
Subarea runoff = 1.749(CFS)
Total initial stream area = 0.750(Ac.)
+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
+++
Process from Point/Station 802.000 to Point/Station
803.000
**** IMPROVED CHANNEL TRAVEL TIME ****
___________________________________________________________________
___
Upstream point elevation = 275.190(Ft.)
Downstream point elevation = 274.990(Ft.)
Channel length thru subarea = 116.000(Ft.)
Channel base width = 0.500(Ft.)
Slope or 'Z' of left channel bank = 1.300
Slope or 'Z' of right channel bank = 1.300
Manning's 'N' = 0.015
Maximum depth of channel = 1.000(Ft.)
Flow(q) thru subarea = 1.749(CFS)
Depth of flow = 0.654(Ft.), Average velocity = 1.980(Ft/s)
Channel flow top width = 2.201(Ft.)
Flow Velocity = 1.98(Ft/s)
Travel time = 0.98 min.
Time of concentration = 5.61 min.
Critical depth = 0.484(Ft.)
+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
+++
Process from Point/Station 803.000 to Point/Station
910.000
**** PIPEFLOW TRAVEL TIME (User specified size) ****
___________________________________________________________________
___
Upstream point/station elevation = 267.940(Ft.)
Downstream point/station elevation = 261.240(Ft.)
Pipe length = 346.00(Ft.) Slope = 0.0194 Manning's N = 0.013
No. of pipes = 1 Required pipe flow = 1.749(CFS)
Given pipe size = 10.00(In.)
Calculated individual pipe flow = 1.749(CFS)
Normal flow depth in pipe = 5.43(In.)
Flow top width inside pipe = 9.96(In.)
Critical Depth = 7.12(In.)
Pipe flow velocity = 5.78(Ft/s)
Travel time through pipe = 1.00 min.
Time of concentration (TC) = 6.61 min.
+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
+++
Process from Point/Station 803.000 to Point/Station
910.000
**** CONFLUENCE OF MINOR STREAMS ****
___________________________________________________________________
___
Along Main Stream number: 2 in normal stream number 1
Stream flow area = 0.750(Ac.)
Runoff from this stream = 1.749(CFS)
Time of concentration = 6.61 min.
Rainfall intensity = 6.493(In/Hr)
+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
+++
Process from Point/Station 901.000 to Point/Station
902.000
**** INITIAL AREA EVALUATION ****
___________________________________________________________________
___
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
[UNDISTURBED NATURAL TERRAIN ]
(Permanent Open Space )
Impervious value, Ai = 0.000
Sub-Area C Value = 0.300
Initial subarea total flow distance = 85.000(Ft.)
Highest elevation = 308.710(Ft.)
Lowest elevation = 275.250(Ft.)
Elevation difference = 33.460(Ft.) Slope = 39.365 %
Top of Initial Area Slope adjusted by User to 30.000 %
INITIAL AREA TIME OF CONCENTRATION CALCULATIONS:
The maximum overland flow distance is 100.00 (Ft)
for the top area slope value of 30.00 %, in a development type of
Permanent Open Space
In Accordance With Figure 3-3
Initial Area Time of Concentration = 4.63 minutes
TC = [1.8*(1.1-C)*distance(Ft.)^.5)/(% slope^(1/3)]
TC = [1.8*(1.1-0.3000)*( 100.000^.5)/( 30.000^(1/3)]= 4.63
Calculated TC of 4.634 minutes is less than 5 minutes,
resetting TC to 5.0 minutes for rainfall intensity calculations
Rainfall intensity (I) = 7.772(In/Hr) for a 100.0 year storm
Effective runoff coefficient used for area (Q=KCIA) is C = 0.300
Subarea runoff = 1.399(CFS)
Total initial stream area = 0.600(Ac.)
+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
+++
Process from Point/Station 902.000 to Point/Station
903.000
**** IMPROVED CHANNEL TRAVEL TIME ****
___________________________________________________________________
___
Upstream point elevation = 277.830(Ft.)
Downstream point elevation = 270.710(Ft.)
Channel length thru subarea = 362.000(Ft.)
Channel base width = 0.500(Ft.)
Slope or 'Z' of left channel bank = 1.300
Slope or 'Z' of right channel bank = 1.300
Manning's 'N' = 0.015
Maximum depth of channel = 1.000(Ft.)
Flow(q) thru subarea = 1.399(CFS)
Depth of flow = 0.327(Ft.), Average velocity = 4.628(Ft/s)
Channel flow top width = 1.350(Ft.)
Flow Velocity = 4.63(Ft/s)
Travel time = 1.30 min.
Time of concentration = 5.94 min.
Critical depth = 0.434(Ft.)
+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
+++
Process from Point/Station 903.000 to Point/Station
910.000
**** PIPEFLOW TRAVEL TIME (User specified size) ****
___________________________________________________________________
___
Upstream point/station elevation = 265.200(Ft.)
Downstream point/station elevation = 261.240(Ft.)
Pipe length = 62.00(Ft.) Slope = 0.0639 Manning's N = 0.013
No. of pipes = 1 Required pipe flow = 1.399(CFS)
Given pipe size = 10.00(In.)
Calculated individual pipe flow = 1.399(CFS)
Normal flow depth in pipe = 3.43(In.)
Flow top width inside pipe = 9.49(In.)
Critical Depth = 6.35(In.)
Pipe flow velocity = 8.47(Ft/s)
Travel time through pipe = 0.12 min.
Time of concentration (TC) = 6.06 min.
+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
+++
Process from Point/Station 910.000 to Point/Station
910.000
**** CONFLUENCE OF MINOR STREAMS ****
___________________________________________________________________
___
Along Main Stream number: 2 in normal stream number 2
Stream flow area = 0.600(Ac.)
Runoff from this stream = 1.399(CFS)
Time of concentration = 6.06 min.
Rainfall intensity = 6.866(In/Hr)
Summary of stream data:
Stream Flow rate TC Rainfall Intensity
No. (CFS) (min) (In/Hr)
1 1.749 6.61 6.493
2 1.399 6.06 6.866
Qmax(1) =
1.000 * 1.000 * 1.749) +
0.946 * 1.000 * 1.399) + = 3.072
Qmax(2) =
1.000 * 0.917 * 1.749) +
1.000 * 1.000 * 1.399) + = 3.003
Total of 2 streams to confluence:
Flow rates before confluence point:
1.749 1.399
Maximum flow rates at confluence using above data:
3.072 3.003
Area of streams before confluence:
0.750 0.600
Results of confluence:
Total flow rate = 3.072(CFS)
Time of concentration = 6.608 min.
Effective stream area after confluence = 1.350(Ac.)
+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
+++
Process from Point/Station 910.000 to Point/Station
911.000
**** PIPEFLOW TRAVEL TIME (User specified size) ****
___________________________________________________________________
___
Upstream point/station elevation = 261.240(Ft.)
Downstream point/station elevation = 259.030(Ft.)
Pipe length = 110.00(Ft.) Slope = 0.0201 Manning's N = 0.013
No. of pipes = 1 Required pipe flow = 3.072(CFS)
Given pipe size = 18.00(In.)
Calculated individual pipe flow = 3.072(CFS)
Normal flow depth in pipe = 5.55(In.)
Flow top width inside pipe = 16.62(In.)
Critical Depth = 8.00(In.)
Pipe flow velocity = 6.64(Ft/s)
Travel time through pipe = 0.28 min.
Time of concentration (TC) = 6.88 min.
+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
+++
Process from Point/Station 911.000 to Point/Station
911.000
**** CONFLUENCE OF MAIN STREAMS ****
___________________________________________________________________
___
The following data inside Main Stream is listed:
In Main Stream number: 2
Stream flow area = 1.350(Ac.)
Runoff from this stream = 3.072(CFS)
Time of concentration = 6.88 min.
Rainfall intensity = 6.324(In/Hr)
Summary of stream data:
Stream Flow rate TC Rainfall Intensity
No. (CFS) (min) (In/Hr)
1 24.190 4.99 7.772
2 3.072 6.88 6.324
Qmax(1) =
1.000 * 1.000 * 24.190) +
1.000 * 0.725 * 3.072) + = 26.417
Qmax(2) =
0.814 * 1.000 * 24.190) +
1.000 * 1.000 * 3.072) + = 22.752
Total of 2 main streams to confluence:
Flow rates before confluence point:
24.190 3.072
Maximum flow rates at confluence using above data:
26.417 22.752
Area of streams before confluence:
3.620 1.350
Results of confluence:
Total flow rate = 26.417(CFS)
Time of concentration = 4.992 min.
Effective stream area after confluence = 4.970(Ac.)
+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
+++
Process from Point/Station 911.000 to Point/Station
912.000
**** PIPEFLOW TRAVEL TIME (User specified size) ****
___________________________________________________________________
___
Upstream point/station elevation = 259.030(Ft.)
Downstream point/station elevation = 257.850(Ft.)
Pipe length = 69.00(Ft.) Slope = 0.0171 Manning's N = 0.013
No. of pipes = 1 Required pipe flow = 26.417(CFS)
Given pipe size = 24.00(In.)
Calculated individual pipe flow = 26.417(CFS)
Normal flow depth in pipe = 17.67(In.)
Flow top width inside pipe = 21.15(In.)
Critical Depth = 21.54(In.)
Pipe flow velocity = 10.65(Ft/s)
Travel time through pipe = 0.11 min.
Time of concentration (TC) = 5.10 min.
+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
+++
Process from Point/Station 912.000 to Point/Station
913.000
**** PIPEFLOW TRAVEL TIME (User specified size) ****
___________________________________________________________________
___
Upstream point/station elevation = 257.850(Ft.)
Downstream point/station elevation = 253.250(Ft.)
Pipe length = 277.00(Ft.) Slope = 0.0166 Manning's N = 0.130
No. of pipes = 1 Required pipe flow = 26.417(CFS)
Given pipe size = 24.00(In.)
NOTE: Normal flow is pressure flow in user selected pipe size.
The approximate hydraulic grade line above the pipe invert is
374.633(Ft.) at the headworks or inlet of the pipe(s)
Pipe friction loss = 377.586(Ft.)
Minor friction loss = 1.647(Ft.) K-factor = 1.50
Pipe flow velocity = 8.41(Ft/s)
Travel time through pipe = 0.55 min.
Time of concentration (TC) = 5.65 min.
+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
+++
Process from Point/Station 913.000 to Point/Station
914.000
**** PIPEFLOW TRAVEL TIME (User specified size) ****
___________________________________________________________________
___
Upstream point/station elevation = 253.250(Ft.)
Downstream point/station elevation = 240.740(Ft.)
Pipe length = 59.00(Ft.) Slope = 0.2120 Manning's N = 0.013
No. of pipes = 1 Required pipe flow = 26.417(CFS)
Given pipe size = 24.00(In.)
Calculated individual pipe flow = 26.417(CFS)
Normal flow depth in pipe = 8.24(In.)
Flow top width inside pipe = 22.79(In.)
Critical Depth = 21.54(In.)
Pipe flow velocity = 27.67(Ft/s)
Travel time through pipe = 0.04 min.
Time of concentration (TC) = 5.68 min.
End of computations, total study area = 4.970 (Ac.)
1
2
1
Watershed Model Schematic Hydraflow Hydrographs Extension for Autodesk® Civil 3D® by Autodesk, Inc. v2025
Project: 24-172-Attenuation-100yr-City Datum.gpw Tuesday, 10 / 8 / 2024
Hyd.Origin Description
Legend
1 Manual Post Condition (Basins 1-7)
2 Reservoir IMP-1
Hydrograph Return Period Recap
2
Hyd. Hydrograph Inflow Peak Outflow (cfs) Hydrograph
No. type hyd(s)Description
(origin) 1-yr 2-yr 3-yr 5-yr 10-yr 25-yr 50-yr 100-yr
1 Manual ------ ------- ------- ------- ------- ------- ------- ------- 24.19 Post Condition (Basins 1-7)
2 Reservoir 1 ------- ------- ------- ------- ------- ------- ------- 8.468 IMP-1
Proj. file: 24-172-Attenuation-100yr-City Datum.gpw Tuesday, 10 / 8 / 2024
Hydraflow Hydrographs Extension for Autodesk® Civil 3D® by Autodesk, Inc. v2025
Hydrograph Summary Report
3
Hyd. Hydrograph Peak Time Time to Hyd. Inflow Maximum Total Hydrograph
No. type flow interval Peak volume hyd(s) elevation strge used Description
(origin) (cfs) (min) (min) (cuft) (ft) (cuft)
1 Manual 24.19 5 245 34,347 ------ ------ ------ Post Condition (Basins 1-7)
2 Reservoir 8.468 5 250 32,900 1 266.12 8,920 IMP-1
24-172-Attenuation-100yr-City Datum.gpw Return Period: 100 Year Tuesday, 10 / 8 / 2024
Hydraflow Hydrographs Extension for Autodesk® Civil 3D® by Autodesk, Inc. v2025
RATIONAL METHOD HYDROGRAPH PROGRAM
COPYRIGHT 1992, 2001 RICK ENGINEERING COMPANY
RUN DATE 10/2/2024
HYDROGRAPH FILE NAME Text1
TIME OF CONCENTRATION 5 MIN.
6 HOUR RAINFALL 2.95 INCHES
BASIN AREA 3.62 ACRES
RUNOFF COEFFICIENT 0.89
PEAK DISCHARGE 24.19 CFS
TIME (MIN) = 0
TIME (MIN) = 5
TIME (MIN)= 10
TIME (MIN) = 15
TIME (MIN) = 20
TIME (MIN) = 25
TIME (MIN) = 30
TIME (MIN) = 35
TIME (MIN)= 40
TIME (MIN)= 45
TIME (MIN)= 50
TIME (MIN)= 55
TIME (MIN)= 60
TIME (MIN)= 65
TIME (MIN)= 70
TIME (MIN)= 75
TIME (MIN)= 80
TIME (MIN)= 85
TIME (MIN)= 90
TIME (MIN)= 95
TIME (MIN)= 100
TIME (MIN)= 105
TIME (MIN)= 110
TIME (MIN)= 115
TIME (MIN)= 120
TIME (MIN)= 125
TIME (MIN)= 130
TIME (MIN)= 135
TIME (MIN)= 140
TIME (MIN)= 145
TIME (MIN)= 150
TIME (MIN)= 155
TIME (MIN)= 160
TIME (MIN)= 165
TIME (MIN)= 170
TIME (MIN)= 175
TIME (MIN)= 180
TIME (MIN)= 185
TIME (MIN)= 190
TIME (MIN)= 195
TIME (MIN)= 200
TIME (MIN)= 205
TIME (MIN)= 210
TIME (MIN)= 215
TIME (MIN)= 220
TIME (MIN)= 225
TIME (MIN)= 230
TIME (MIN)= 235
TIME (MIN)= 240
TIME (MIN)= 245
TIME (MIN)= 250
TIME (MIN)= 255
TIME (MIN)= 260
TIME (MIN)= 265
TIME (MIN)= 270
TIME (MIN) = 275
TIME (MIN) = 280
TIME (MIN) = 285
TIME (MIN) = 290
TIME (MIN) = 295
TIME (MIN) = 300
TIME (MIN) = 305
TIME (MIN)= 310
TIME (MIN)= 315
TIME (MIN) = 320
TIME (MIN) = 325
TIME (MIN) = 330
TIME (MIN) = 335
TIME (MIN) = 340
TIME (MIN)= 345
TIME (MIN)= 350
TIME (MIN)= 355
DISCHARGE (CFS) = 0
DISCHARGE (CFS) = 0.6
DISCHARGE (CFS) = 0.6
DISCHARGE (CFS) = 0.6
DISCHARGE (CFS) = 0.6
DISCHARGE (CFS) = 0.6
DISCHARGE (CFS) = 0.6
DISCHARGE (CFS) = 0.6
DISCHARGE (CFS) = 0.6
DISCHARGE (CFS) = 0.6
DISCHARGE (CFS) = 0.6
DISCHARGE (CFS) = 0.7
DISCHARGE (CFS) = 0.7
DISCHARGE (CFS) = 0.7
DISCHARGE (CFS) = 0.7
DISCHARGE (CFS) = 0.7
DISCHARGE (CFS) = 0.7
DISCHARGE (CFS) = 0.7
DISCHARGE (CFS) = 0.7
DISCHARGE (CFS) = 0.8
DISCHARGE (CFS) = 0.8
DISCHARGE (CFS) = 0.8
DISCHARGE (CFS) = 0.8
DISCHARGE (CFS) = 0.8
DISCHARGE (CFS) = 0.9
DISCHARGE (CFS) = 0.9
DISCHARGE (CFS) = 0.9
DISCHARGE (CFS) = 0.9
DISCHARGE (CFS) = 1
DISCHARGE (CFS) = 1
DISCHARGE (CFS) = 1
DISCHARGE (CFS) = 1.1
DISCHARGE (CFS) = 1.1
DISCHARGE (CFS) = 1.2
DISCHARGE (CFS) = 1.2
DISCHARGE (CFS) = 1.3
DISCHARGE (CFS) = 1.3
DISCHARGE (CFS) = 1.4
DISCHARGE (CFS) = 1.5
DISCHARGE (CFS) = 1.6
DISCHARGE (CFS)= 1.7
DISCHARGE (CFS) = 1.8
DISCHARGE (CFS) = 2
DISCHARGE (CFS) = 2.2
DISCHARGE (CFS) = 2.4
DISCHARGE (CFS) = 3
DISCHARGE (CFS) = 3.4
DISCHARGE (CFS) = 5
DISCHARGE (CFS)= 7.8
DISCHARGE (CFS) = 24.19
DISCHARGE (CFS) = 4
DISCHARGE (CFS)= 2.7
DISCHARGE (CFS) = 2.1
DISCHARGE (CFS)= 1.7
DISCHARGE (CFS) = 1.5
DISCHARGE (CFS) = 1.4
DISCHARGE (CFS) = 1.2
DISCHARGE (CFS) = 1.1
DISCHARGE (CFS) = 1
DISCHARGE (CFS) = 1
DISCHARGE (CFS) = 0.9
DISCHARGE (CFS) = 0.9
DISCHARGE (CFS) = 0.8
DISCHARGE (CFS) = 0.8
DISCHARGE (CFS) = 0.8
DISCHARGE (CFS) = 0.7
DISCHARGE (CFS) = 0.7
DISCHARGE (CFS)= 0.7
DISCHARGE (CFS)= 0.7
DISCHARGE (CFS) = 0.6
DISCHARGE (CFS) = 0.6
DISCHARGE (CFS) = 0.6
TIME (MIN) = 360
TIME (MIN) = 365
DISCHARGE (CFS) = 0.6
DISCHARGE (CFS) = 0
Hydrograph Report
Hydraflow Hydrographs Extension for Autodesk® Civil 3D® by Autodesk, Inc. v2025 Tuesday, 10 / 8 / 2024
Hyd. No. 1
Post Condition (Basins 1-7)
Hydrograph type = Manual Peak discharge = 24.19 cfs
Storm frequency = 100 yrs Time to peak = 4.08 hrs
Time interval = 5 min Hyd. volume = 34,347 cuft
4
0.0 1.0 2.0 3.0 4.0 5.0 6.0 7.0
Q (cfs)
0.00 0.00
4.00 4.00
8.00 8.00
12.00 12.00
16.00 16.00
20.00 20.00
24.00 24.00
28.00 28.00
Q (cfs)
Time (hrs)
Post Condition (Basins 1-7)
Hyd. No. 1 -- 100 Year
Hyd No. 1
Hydrograph Report
Hydraflow Hydrographs Extension for Autodesk® Civil 3D® by Autodesk, Inc. v2025 Tuesday, 10 / 8 / 2024
Hyd. No. 2
IMP-1
Hydrograph type = Reservoir Peak discharge = 8.468 cfs
Storm frequency = 100 yrs Time to peak = 4.17 hrs
Time interval = 5 min Hyd. volume = 32,900 cuft
Inflow hyd. No. = 1 - Post Condition (Basins 1-7)Max. Elevation = 266.12 ft
Reservoir name = IMP-1 Max. Storage = 8,920 cuft
Storage Indication method used.
5
0.0 1.0 2.0 3.0 4.0 5.0 6.0 7.0
Q (cfs)
0.00 0.00
4.00 4.00
8.00 8.00
12.00 12.00
16.00 16.00
20.00 20.00
24.00 24.00
28.00 28.00
Q (cfs)
Time (hrs)
IMP-1
Hyd. No. 2 -- 100 Year
Hyd No. 2 Hyd No. 1 Total storage used = 8,920 cuft
Pond Report 6
Hydraflow Hydrographs Extension for Autodesk® Civil 3D® by Autodesk, Inc. v2025 Tuesday, 10 / 8 / 2024
Pond No. 1 - IMP-1
Pond Data
Contours -User-defined contour areas. Average end area method used for volume calculation. Begining Elevation = 259.42 ft
Stage / Storage Table
Stage (ft) Elevation (ft) Contour area (sqft) Incr. Storage (cuft) Total storage (cuft)
0.00 259.42 10 0 0
2.75 262.17 10 28 28
2.75 262.17 10 0 28
3.25 262.67 10 5 33
3.25 262.67 10 0 335.00 264.42 10 17 50
5.00 264.42 10 0 50
5.50 264.92 5,583 1,395 1,445
6.00 265.42 6,044 2,907 4,352
6.50 265.92 6,520 3,141 7,493
7.00 266.42 8,028 3,637 11,130
Culvert / Orifice Structures Weir Structures
[A] [B] [C] [PrfRsr] [A] [B] [C] [D]
Rise (in)= 24.00 Inactive 0.00 0.00
Span (in)= 24.00 0.00 0.00 0.00
No. Barrels = 1 100
Invert El. (ft)= 259.54 0.00 0.00 0.00
Length (ft)= 53.00 0.00 0.00 0.00
Slope (%)= 1.70 0.00 0.00 n/a
N-Value = .013 .013 .013 n/a
Orifice Coeff.= 0.60 0.60 0.60 0.60
Multi-Stage = n/a Yes No No
Crest Len (ft)= 4.80 0.00 0.00 0.00
Crest El. (ft)= 264.92 0.00 0.00 0.00
Weir Coeff.= 3.33 3.33 3.33 3.33
Weir Type = 1 --- --- ---
Multi-Stage = Yes NoNoNo
Exfil.(in/hr)= 0.000 (by Contour)
TW Elev. (ft)= 0.00
Note: Culvert/Orifice outflows are analyzed under inlet (ic) and outlet (oc) control. Weir risers checked for orifice conditions (ic) and submergence (s).
0.00 1.00 2.00 3.00 4.00 5.00 6.00 7.00 8.00 9.00 10.00
Stage (ft)
0.00 259.42
2.00 261.42
4.00 263.42
6.00 265.42
8.00 267.42
Elev (ft)
Discharge (cfs)
Stage / Discharge
Total Q Culv A
Weir AStruct HG
Pond No. 1 -IMP-1
8.00
7.00
6.00
5.00
4.00
3.00
2.00
1.00
0.00
Stage (fl)
4.80 ft Riser
WeirA -Elev. 264.92
Project: 24-172-Attenuation-1 00yr-City Datum.gpw
\
Front View
Hydraflow Hydrographs Extension for Autodesk® Civil 3D® by Autodesk, Inc. v2025
Top of pond
Elev. 266.42
'\__ Bottom of pond
Elev. 259.42
53.0 LF of 24.0 in@ 1.70%
CulvA -Inv. 259.54
NTS -Looking Downstream
----100-yr
Inflow hydrograph = 1. Manual -Post Condition (Basins 1-7)
Tuesday, 10/8/2024
Hydraflow Storm Sewers Extension for Autodesk® Civil 3D® Plan
Structure - (3)
Structure - (6)
Project File: Basin SD to Outfall.stm Number of lines: 5 Date: 10/2/2024
Storm Sewers v2023.00
Storm Sewer Inventory Report Page 1
Line Alignment Flow Data Physical Data Line ID
No.
Dnstr Line Defl June Known Drng Runoff Inlet Invert Line Invert Line Line N J-Loss Inlet/
Line Length angle Type Q Area Coeff Time EIDn Slope El Up Size Shape Value Coeff Rim El
No. (ft) (deg) (cfs) (ac) (C) (min) (ft) (%) (ft) (in) (n) (K) (ft)
1 End 59.000 -128.961 MH 0.00 0.00 0.00 0.0 240.74 21.20 253.25 24 Cir 0.013 1.00 266.74 1
2 1 110.580 84.371 MH 0.00 0.00 0.00 0.0 253.25 1.65 255.08 24 Cir 0.013 0.15 266.74 2
3 2 166.300 0.000 None 0.00 0.00 0.00 0.0 255.08 1.67 257.85 24 Cir 0.013 0.60 264.74 3
4 3 68.570 -33.377 MH 0.00 0.00 0.00 0.0 257.85 1.72 259.03 24 Cir 0.013 0.31 265.74 4
5 4 30.780 15.294 Grate 26.42 0.00 0.00 0.0 259.03 1.66 259.54 24 Cir 0.013 1.00 266.54 5
Project File: Basin SD to Outfall.stm Number of lines: 5 Date: 10/2/2024
Storm Sewers v2025.00
Storm Sewer Summary Report Page 1
Line Line ID Flow Line Line Line Invert Invert Line HGL HGL Minor HGL Dns Junction
No. rate Size shape length ELDn EL Up Slope Down Up loss Junct Line Type
(cfs) (in) (ft) (ft) (ft) (%) (ft) (ft) (ft) (ft) No.
1 1 26.42 24 Cir 59.000 240.74 253.25 21.203 241.43 255.04 1.23 255.04 End Manhole
2 2 26.42 24 Cir 110.580 253.25 255.08 1.655 255.04 256.87 n/a 256.87 1 Manhole
3 3 26.42 24 Cir 166.300 255.08 257.85 1.666 256.87 259.64 0.74 259.64 2 None
4 4 26.42 24 Cir 68.570 257.85 259.03 1.721 259.64 260.82 0.38 260.82 3 Manhole
5 5 26.42 24 Cir 30.780 259.03 259.54 1.657 260.82 261.33 1.23 261.33 4 Grate
Project File: Basin SD to Outfall.stm Number of lines: 5 I Run Date: 10/2/2024
NOTES: Return period= 100 Yrs.
Storm Sewers v2025.00
Hydraulic Grade Line Computations Page 1
Line Size Q Downstream Len Upstream Check JL Minor
coeff loss
Invert HGL Depth Area Vel Vel EGL Sf Invert HGL Depth Area Vel Vel EGL Sf Ave Enrgy
elev elev head elev elev elev head elev Sf loss
(in) (cfs) (ft) (ft) (ft) (sqft) (ft/s) (ft) (ft) (%) (ft) (ft) (ft) (ft) (sqft) (ft/s) (ft) (ft) (%) (%) (ft) (K) (ft)
1 24 26.42 240.74 241.43 0.69 0.96 27.50 1.23 242.66 0.000 59.000 253.25 255.04 1.79** 2.97 8.89 1.23 256.27 0.000 0.000 n/a 1.00 1.23
2 24 26.42 253.25 255.04 1.79* 2.97 8.89 1.23 256.27 0.000 110.58 D255.08 256.87 1.79** 2.97 8.89 1.23 258.10 0.000 0.000 n/a 0.15 n/a
3 24 26.42 255.08 256.87 1.79* 2.97 8.89 1.23 258.10 0.000 166.30 D257.85 259.64 1.79** 2.97 8.89 1.23 260.87 0.000 0.000 n/a 0.60 0.74
4 24 26.42 257.85 259.64 1.79* 2.97 8.89 1.23 260.87 0.000 68.570 259.03 260.82 1.79** 2.97 8.89 1.23 262.05 0.000 0.000 n/a 0.31 0.38
5 24 26.42 259.03 260.82 1.79* 2.97 8.89 1.23 262.05 0.000 30.780 259.54 261.33 1.79** 2.97 8.89 1.23 262.56 0.000 0.000 n/a 1.00 1.23
Project File: Basin SD to Outfall.stm I Number of lines: 5 I Run Date: 10/2/2024
Notes: * depth assumed; ** Critical depth. c = cir e = ellip b = box
Storm Sewers v2025.00
Storm Sewer Profile
Elev. (ft)
288.00
277.00
266.00
255.00
244.00
233.00
I ~:; o~I'-: ONO ci . v oiiJN
c!:, -ci ii:i
,2!E>
Cl) C) -=
J
I I
I
C ...J
' 0 0 m LO + 0
m
cii
I
/
:i QC -V LO LO l'-:NN co •• co C') C') N LO LO NN
wu::lu::l
_§ > >
a::-=-=
I /1/ -I §. V •-·
I ~/ v ~ V
////
"l/ r,
~ ::,:; .UUULT-L4 (g/ L'
~ <>A• (ro 1.65%
.LUv/o
50 ----HGL----EGL
0 100 150
N
C ...J
' a:,
"? m <O + ~ s Cl)
:i QC -v a:, a> 1--:oo co •• CO LO LO N LO LO NN
wu::lu::l
_§ > >
a::-=-=
·--f 74• ® 1.67%
200 250 300
Reach (ft)
C') .. ::::,
...J I'-; LO ;;; ' v a> a> a> <O •• a> Nl'--1'--
LO .IOIO -NN C') w .. + -ciiiJiiJ C')
C s;tQC
s E>>
Cl) C>.=.=
350
v
C ...J
' LO v
-<i 0 + v
m
cii
-
:i QC -v t'? t'? 1--:oo LO • • comm N LO LO NN
wu::lu::l
_§ > >
a::-=-=
"'-'--...,
I
Proj . file: Basin SD to Outfall.stm
~
LO
C ...J
' C')
("!
LO C')
+ v s Cl)
-
:i
Q Vs;t "? LO IO • com NIO N
iiJii:l
_§ > a::.=
~U./0
288.00
277.00
266.00
255.00
µL f -24" @ 1.66%
68.57 PU-24"@ 1.7"t.' o
400
244.00
233.00
450
Storm Sewers
.
BASIN-3
2.85 AC
BASIN-1
1.87 AC
BASIN-2
0.25 AC
(SW
A
P
)
T
O
B
E
T
R
E
A
T
E
D
14,
7
2
6
S
F
(SW
A
P
)
N
O
T
T
O
B
E
T
R
E
A
T
E
D
23,
6
6
7
S
F
(SWAP) TO BE TREATED
12,400 SF
DATE: Oct 08, 24 2:22pm by:massy.fatini
FILE:C:\Users\massy.fatini\DC\ACCDocs\SWS Engineering\2024\Project Files\24-172\PROD\Reports\Hydrology\24-172_PRE Drainage Map.dwg
1635 Lake San Marcos Drive, Suite 200
San Marcos, CA 92078
P: 760-744-0011 F: 760-744-0046
PRE DRAINAGE MAP
CARRILLO ELEMENTARY SCHOOL
FOR
LEGEND
BASIN-8
0.75 AC
BASIN-9
0.60 AC
BASIN-2
0.22 AC
BASIN-7
1.84 AC
(SW
A
P
)
T
O
B
E
T
R
E
A
T
E
D
14,
7
2
6
S
F
BASIN-1
0.49 AC
BASIN-3
0.58 AC
BASIN-5
0.09 AC
BAS
I
N
-
4
0.1
5
A
C
BASIN-6
0.25 AC
(SW
A
P
)
N
O
T
T
O
B
E
T
R
E
A
T
E
D
23,
6
6
7
S
F
(SWAP) TO BE TREATED
12,400 SF
TOTAL Q INTO BASIN = 24.19 CFS
TOTAL A INTO BASIN = 4.97 AC
ATTENUATED DISCHARGE Q
INTO PROPOSED PIPE = 8.47 CFS
TOTAL Q = 9.82 CFS
TOTAL A = 1.53 AC
TOTAL Q = 26.42 CFS
AFTER DETENTION = 11.26 CFS
DATE: Oct 08, 24 2:25pm by:massy.fatiniFILE:C:\Users\massy.fatini\DC\ACCDocs\SWS Engineering\2024\Project Files\24-172\PROD\Reports\Hydrology\24-172_POST Drainage Map.dwg
1635 Lake San Marcos Drive, Suite 200
San Marcos, CA 92078
P: 760-744-0011 F: 760-744-0046
POST DRAINAGE MAP
CARRILLO ELEMENTARY SCHOOL
FOR
LEGEND