Appendix F Downtown Drainage StudyAppendix F — Downtown Area Drainage Study for
the City of La Quinta
La Quinta Village Build -out Plan EIR
City of La Quinta
DOWNTOWN AREA DRAINAGE STUDY
FOR
CITY OF LA QUINTA
COUNTY OF RIVERSIDE, CALIFORNIA
PREPARED BY:
P S 0 M A S
Date: 01/04/2008
TABLE OF CONTENTS
• GENERAL DISCUSSION
a. Introduction
b. Study Area Location
c. Hydrologic Methodology
• HYDROLOGIC CONDITIONS
a. Existing Conditions
b. Existing Site Drainage
c. Hydrology Summary Table
• RECOMMENDATIONS
• HYDROLOGIC AND HYDRAULIC CALCULATIONS
a. Off-site Runoff Hydrologic Calculations
b. Study Area Runoff Hydrologic Calculations
c. Streets and Catch Basin Capacities
d. Reinforced Concrete Boxes Capacities
• HYDROLOGY MAP
a. Downtown Drainage Study Hydrology Map
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GENERAL DISCUSSION
a. INTRODUCTION
The downtown area of the City of La Quinta between Avenida Bermudas and Desert Club Drive
and between Calle Tampico and Avenue 52 has generally been developed without requiring
drainage detention on-site due to the commercial nature of the development and limited space.
This study evaluates this situation to determine if this practice has resulted in adverse impacts in
the area or downstream.
b. STUDY AREA LOCATION
The study area is approximately 25.6 acres and, as mentioned above, is bounded on the east by
Desert Club Drive, on the west by Avenida Bermudas, on the north by Calle Tampico, and on
the south by Avenue 52. See the Study Area Location Map below:
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c. HYDROLOGIC METHODOLOGY
The Rational Method, as described in the Riverside County Hydrology Manual, was used to
calculate the existing peak flows from a 10 -year storm frequency. The hydrology calculations
were conducted through the use of "CivilDesign" hydrology computer program by CivilDesign
Corporation. The hydrology calculations are based on Soil Group A (Sandy Loam / Loamy
Sand). The selection of the soil type is based on Percolation Testing Technical Memorandum
from GeoPentech (September 22, 2004) included in the Master Drainage Plan as Appendix E.
Also, in order to take into account the effect of existing dry wells and sand filters within the
study area, an impervious percentage of 65% is used in the CivilDesign program.
The attached hydrology map depicts the accumulated runoff for the total drainage area flowing
to the Calle Tampico drainage system.
HYDROLOGIC CONDITIONS
a. EXISTING CONDITIONS
The study area is approximately 25.6 acres with a 10 -year frequency storm runoff of 41.5 cfs.
An off-site drainage area of 48.5 acres, located westerly and basically upstream of the study area,
is contributing to the drainage area with a 10 -year frequency storm runoff of 70.9 cfs. The study
area is mainly occupied by commercial buildings. Ground surface cover consists of existing
asphalt concrete pavements and some landscaping. The delineation of the drainage areas is
shown in Downtown Drainage Study Hydrology Map presented in this report.
b. EXISTING SITE DRAINAGE
This study analyzes these two major drainage areas that drain by sheet flow then street flow
towards the north and east and discharge into Calle Tampico. The first area is the off-site area
west of the downtown area. This area drains to Avenida Navarro and Avenida Bermudas
towards the north and discharges into Calle Tampico. The off-site area consists of residential
development, commercial areas and La Quinta Village Park. The drainage system does not
include catch basins or pipes. Dry wells and local retention areas exist in the park. It is assumed
that the runoff water drains to those dry wells then infiltrates into the soil.
The second major area is the downtown area that drains towards Desert Club Drive, then drains
towards the north and discharges into Calle Tampico. The downtown area consists of
commercial sites (retail) and some residential development. The drainage in this area is mostly
sheet flow into local dry wells, sand filters and retention basins, then street flows towards Desert
Club Drive. The street drainage system does not include catch basins in this area.
The runoff from the area west of downtown is intercepted by a 7 -ft catch basin located along
Calle Tampico, between Avenida Bermudas and Desert Club Drive. This catch basin conveys
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the runoff to a 2'H x 6'W double reinforced concrete box that drains from west to east along
Calle Tampico. However, the catch basin capacity collects only 26.5-cfs from the 71-cfs (10 -yr
storm flow) generated from the off-site area. The remaining flow ponds to a depth of 7 -inches,
then flows towards the east and joins the 41.5-cfs runoff from the subject site. The combined
runoff flows east to another catch basin located along Calle Tampico east of Desert Club Drive.
Hydrologic and hydraulic calculations for streets, catch basins and reinforced concrete boxes are
presented in the Hydrologic and Hydraulic Calculations section of this report.
An existing Coachella Valley Water District (CVWD) 60" RCP storm drain flows north along
Desert Club Drive. The 60" RCP conveys overflow runoff from the Crystal Canyon Detention
Basins located south of the study area. The 60" RCP drains from south to north and discharges
into the La Quinta Evacuation Channel. Also, a 66" RCP exists along Avenue 52 south of the
study area. The 66" RCP drains from west to east and conveys a small portion of its flow into
the 60" CVWD RCP in Desert Club Drive via an 18" lateral pipe connection.
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c. HYDROLOGY SUMMARY TABLE
AREA
Acreage
Q10 cfs
A-1
3.6
7.23
A-2
3.8
6.87
A-3
3.8
6.36
A-4
3.8
6.06
A-5
2.5
3.76
A-6
1.8
2.45
A-7
2.2
4.03
A-8
2.2
2.65
A-9
3.6
6.78
A-10
5.4
8.76
A-11
6.7
6.85
A-12
2.2
3.15
A-13
2
2.66
A-14
1
1.99
A-15
0.8
1.23
A-16
2.1
2.64
A-17
1
1.18
TOTAL
48.5
70.97
B-1
4
8
B-2
5.1
9.1
B-3
3.1
5.2
B-4
5.4
8.22
B-5
4
5.67
B-6
4
5.29
TOTAL
25.6
41.48
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RECOMMENDATIONS
Based on existing studies and the hydrologic studies presented in the Hydrologic
Calculations section of this report, the downtown study area is subject to flooding in the
northern reaches of Avenida Bermudas, Desert Club Drive and all along Calle Tampico. The
capacity of the existing catch basins and 2'H x 6'W DBL. RCB are not enough to convey the
10 -year peak storm runoff from the downtown area and adjacent neighborhood. Therefore,
at a minimum, bio -retention, dry wells, sand filters and retention basins are recommended for
the proposed and future development within the downtown area to reduce the runoff
generated -similar to the existing facilities in the developed sites in the downtown area. Also,
it is recommended that some catch basins be constructed upstream (south) of the following
intersections, with connections to either dry wells or the RCB storm drain: The roundabout
at Avenida Navarro and Avenida Montezuma, Avenida Navarro and Calle Tampico, and
Avenida Bermudas and Calle Tampico. The locations of the recommended catch basins and
dry wells/sand filters are shown on the Downtown Drainage Study Hydrology Map.
As an alternative to completely eliminate this localized flooding potential, a Preliminary
Design Report could be prepared to determine if a storm drain connection could be made
from just upstream of the existing 2'H x 6'W DBL. RCB in Calle Tampico across Calle
Tampico connecting to the existing storm drain running north adjacent to Avenida Bermudas
that drains into an existing retention basin. It may be that there are existing utility conflicts
that prohibit this connection but this should be investigated to determine if a connection can
be made, hydraulically, which could divert some of the flow to the retention basin.
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HYDROLOGIC AND HYDRAULIC CALCULATIONS
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a. OFF-SITE RUNOFF HYDROLOGIC CALCULATIONS
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Riverside County Rational Hydrology Program
CIVILCADD/CIVILDESIGN Engineering Software,(c) 1989 - 2005 Version 7.1
Rational Hydrology Study Date: 12/13/07 File:LAQ10YR.out
----------------------------------------------------------------------
********* Hydrology Study Control Information **********
English (in -lb) Units used in input data file
----------------------------------------------------------------------
Offsite Area, 10 -yr Storm
Program License Serial Number 6124
----------------------------------------------------------------------
Rational Method Hydrology Program based on
Riverside County Flood Control & Water Conservation District
1978 hydrology manual
Storm event (year) = 10.00 Antecedent Moisture Condition = 2
2 year, 1 hour precipitation = 0.700(In.)
100 year, 1 hour precipitation = 1.600(In.)
Storm event year = 10.0
Calculated rainfall intensity data:
1 hour intensity = 1.070(In/Hr)
Slope of intensity duration curve = 0.5900
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
Process from Point/Station 2.000 to Point/Station 4.000
**** INITIAL AREA EVALUATION ****
Initial area flow distance = 630.000(Ft.)
Top (of initial area) elevation = 61.000(Ft.)
Bottom (of initial area) elevation = 55.000(Ft.)
Difference in elevation = 6.000(Ft.)
Slope = 0.00952 s(percent)= 0.95
TC = k(0.370)*[(length^3)/(elevation change)]^0.2
Initial area time of concentration = 12.364 min.
Rainfall intensity = 2.718(In/Hr) for a 10.0 year storm
CONDOMINIUM subarea type
Runoff Coefficient = 0.739
Decimal fraction soil group A = 1.000
Decimal fraction soil group B = 0.000
Decimal fraction soil group C = 0.000
Decimal fraction soil group D = 0.000
RI index for soil(AMC 2) = 32.00
Pervious area fraction = 0.350; Impervious fraction = 0.650
Initial subarea runoff = 7.233(CFS)
Total initial stream area = 3.600(Ac.)
Pervious area fraction = 0.350
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
Process from Point/Station 4.000 to Point/Station 6.000
**** STREET FLOW TRAVEL TIME + SUBAREA FLOW ADDITION ****
Top of street segment elevation = 55.000(Ft.)
End of street segment elevation = 54.000(Ft.)
Length of street segment = 250.000(Ft.)
Height of curb above gutter flowline = 6.0(In.)
Width of half street (curb to crown) = 16.000(Ft.)
Distance from crown to crossfall grade break = 14.
Slope from gutter to grade break (v/hz) = 0.020
Slope from grade break to crown (v/hz) = 0.020
Street flow is on [2] side(s) of the street
Distance from curb to property line = 10.000(Ft.)
Slope from curb to property line (v/hz) = 0.020
Gutter width = 2.000(Ft.)
Gutter hike from flowline = 1.920(In.)
Manning's N in gutter = 0.0150
Manning's N from gutter to grade break = 0.0150
Manning's N from grade break to crown = 0.0150
Estimated mean flow rate at midpoint of street =
Depth of flow = 0.447(Ft.), Average velocity = 1
Note: depth of flow exceeds top of street crown.
Streetflow hydraulics at midpoint of street travel:
Halfstreet flow width = 16.000(Ft.)
Flow velocity = 1.92(Ft/s)
Travel time = 2.17 min. TC = 14.53 min.
Adding area flow to street
CONDOMINIUM subarea type
Runoff Coefficient = 0.732
Decimal fraction soil group A = 1.000
Decimal fraction soil group B = 0.000
Decimal fraction soil group C = 0.000
Decimal fraction soil group D = 0.000
RI index for soil(AMC 2) = 32.00
Pervious area fraction = 0.350; Impervious fraction
Rainfall intensity = 2.471(In/Hr) for a 10.0
Subarea runoff = 6.870(CFS) for 3.800(Ac.)
Total runoff = 14.103(CFS) Total area =
Street flow at end of street = 14.103(CFS)
Half street flow at end of street = 7.052(CFS)
Depth of flow = 0.478(Ft.), Average velocity = 2
Note: depth of flow exceeds top of street crown.
Flow width (from curb towards crown)= 16.000(Ft.)
000 (Ft
10.765(CFS)
923(Ft/s)
= 0.650
year storm
7.400(Ac.)
141(Ft/s)
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
Process from Point/Station 6.000 to Point/Station 8.000
**** STREET FLOW TRAVEL TIME + SUBAREA FLOW ADDITION ****
Top of street segment elevation = 54.000(Ft.)
End of street segment elevation = 53.000(Ft.)
Length of street segment = 250.000(Ft.)
Height of curb above gutter flowline = 6.0(In.)
Width of half street (curb to crown) = 16.000(Ft.
Distance from crown to crossfall grade break = 14.000(Ft.)
Slope from gutter to grade break (v/hz) = 0.020
Slope from grade break to crown (v/hz) = 0.020
Street flow is on [2] side(s) of the street
Distance from curb to property line = 10.000(Ft.)
Slope from curb to property line (v/hz) = 0.020
Gutter width = 2.000(Ft.)
Gutter hike from flowline = 1.920(In.)
Manning's N in gutter = 0.0150
Manning's N from gutter to grade break = 0.0150
Manning's N from grade break to crown = 0.0150
Estimated mean flow rate at midpoint of street =
Depth of flow = 0.508(Ft.), Average velocity = 2
Warning: depth of flow exceeds top of curb
Note: depth of flow exceeds top of street crown.
Distance that curb overflow reaches into property =
Streetflow hydraulics at midpoint of street travel:
Halfstreet flow width = 16.000(Ft.)
Flow velocity = 2.30(Ft/s)
Travel time = 1.81 min. TC = 16.34 min.
Adding area flow to street
CONDOMINIUM subarea type
Runoff Coefficient = 0.726
Decimal fraction soil group A = 1.000
Decimal fraction soil group B = 0.000
Decimal fraction soil group C = 0.000
Decimal fraction soil group D = 0.000
RI index for soil(AMC 2) = 32.00
Pervious area fraction = 0.350; Impervious fraction
Rainfall intensity = 2.306(In/Hr) for a 10.0
Subarea runoff = 6.363(CFS) for 3.800(Ac.)
Total runoff = 20.467(CFS) Total area =
Street flow at end of street = 20.467(CFS)
Half street flow at end of street = 10.233(CFS)
Depth of flow = 0.539(Ft.), Average velocity = 2
Warning: depth of flow exceeds top of curb
Note: depth of flow exceeds top of street crown.
Distance that curb overflow reaches into property =
Flow width (from curb towards crown)= 16.000(Ft.)
17.340(CFS)
303(Ft/s)
0.38 (Ft.)
= 0.650
year storm
11.200(Ac.)
374(Ft/s)
1.97(Ft.)
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
Process from Point/Station 8.000 to Point/Station 10.000
**** STREET FLOW TRAVEL TIME + SUBAREA FLOW ADDITION ****
Top of street segment elevation = 53.000(Ft.)
End of street segment elevation = 51.000(Ft.)
Length of street segment = 250.000(Ft.)
Height of curb above gutter flowline = 6.0(In.)
Width of half street (curb to crown) = 16.000(Ft.)
Distance from crown to crossfall grade break = 14.000(Ft.)
Slope from gutter to grade break (v/hz) = 0.020
Slope from grade break to crown (v/hz) = 0.020
Street flow is on [2] side(s) of the street
Distance from curb to property line = 10.000(Ft.)
Slope from curb to property line (v/hz) = 0.020
Gutter width = 2.000(Ft.)
Gutter hike from flowline = 1.920(In.)
Manning's N in gutter = 0.0150
Manning's N from gutter to grade break = 0.0150
Manning's N from grade break to crown = 0.0150
Estimated mean flow rate at midpoint of street = 23.550(CFS)
Depth of flow = 0.500(Ft.), Average velocity = 3.234(Ft/s)
Warning: depth of flow exceeds top of curb
Note: depth of flow exceeds top of street crown.
Distance that curb overflow reaches into property = 0.00(Ft.)
Streetflow hydraulics at midpoint of street travel:
Halfstreet flow width = 16.000(Ft.)
Flow velocity = 3.23(Ft/s)
Travel time = 1.29 min. TC = 17.63 min.
Adding area flow to street
CONDOMINIUM subarea type
Runoff Coefficient = 0.723
Decimal fraction soil group A = 1.000
Decimal fraction soil group B = 0.000
Decimal fraction soil group C = 0.000
Decimal fraction soil group D = 0.000
RI index for soil(AMC 2) = 32.00
Pervious area fraction = 0.350; Impervious fraction = 0.650
Rainfall intensity = 2.205(In/Hr) for a 10.0 year storm
Subarea runoff = 6.056(CFS) for 3.800(Ac.)
Total runoff = 26.522(CFS) Total area = 15.000(Ac.)
Street flow at end of street = 26.522(CFS)
Half street flow at end of street = 13.261(CFS)
Depth of flow = 0.523(Ft.), Average velocity = 3.303(Ft/s)
Warning: depth of flow exceeds top of curb
Note: depth of flow exceeds top of street crown.
Distance that curb overflow reaches into property = 1.13(Ft.)
Flow width (from curb towards crown)= 16.000(Ft.)
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
Process from Point/Station 10.000 to Point/Station 12.000
**** STREET FLOW TRAVEL TIME + SUBAREA FLOW ADDITION ****
Top of street segment elevation = 51.000(Ft.)
End of street segment elevation = 50.000(Ft.)
Length of street segment = 250.000(Ft.)
Height of curb above gutter flowline = 6.0(In.)
Width of half street (curb to crown) = 16.000(Ft.)
Distance from crown to crossfall grade break = 14.000(Ft.)
Slope from gutter to grade break (v/hz) = 0.020
Slope from grade break to crown (v/hz) = 0.020
Street flow is on [2] side(s) of the street
Distance from curb to property line = 10.000(Ft.)
Slope from curb to property line (v/hz) = 0.020
Gutter width = 2.000(Ft.)
Gutter hike from flowline = 1.920(In.)
Manning's N in gutter = 0.0150
Manning's N from gutter to grade break = 0.0150
Manning's N from grade break to crown = 0.0150
Estimated mean flow rate at midpoint of street = 28.484(CFS)
Depth of flow = 0.606(Ft.), Average velocity = 2.536(Ft/s)
Warning: depth of flow exceeds top of curb
Note: depth of flow exceeds top of street crown.
Distance that curb overflow reaches into property = 5.30(Ft.)
Streetflow hydraulics at midpoint of street travel:
Halfstreet flow width = 16.000(Ft.)
Flow velocity = 2.54(Ft/s)
Travel time = 1.64 min. TC = 19.27 min.
Adding area flow to street
CONDOMINIUM subarea type
Runoff Coefficient = 0.719
Decimal fraction soil group A = 1.000
Decimal fraction soil group B = 0.000
Decimal fraction soil group C = 0.000
Decimal fraction soil group D = 0.000
RI index for soil(AMC 2) = 32.00
Pervious area fraction = 0.350; Impervious fraction = 0.650
Rainfall intensity = 2.092(In/Hr) for a 10.0 year storm
Subarea runoff = 3.759(CFS) for 2.500(Ac.)
Total runoff = 30.281(CFS) Total area = 17.500(Ac.)
Street flow at end of street = 30.281(CFS)
Half street flow at end of street = 15.140(CFS)
Depth of flow = 0.619(Ft.), Average velocity = 2.569(Ft/s)
Warning: depth of flow exceeds top of curb
Note: depth of flow exceeds top of street crown.
Distance that curb overflow reaches into property = 5.94(Ft.)
Flow width (from curb towards crown)= 16.000(Ft.)
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
Process from Point/Station 12.000 to Point/Station 14.000
**** STREET FLOW TRAVEL TIME + SUBAREA FLOW ADDITION ****
Top of street segment elevation = 50.000(Ft.)
End of street segment elevation = 46.000(Ft.)
Length of street segment = 575.000(Ft.)
Height of curb above gutter flowline = 6.0(In.)
Width of half street (curb to crown) = 20.000(Ft.)
Distance from crown to crossfall grade break = 18.
Slope from gutter to grade break (v/hz) = 0.020
Slope from grade break to crown (v/hz) = 0.020
Street flow is on [2] side(s) of the street
Distance from curb to property line = 13.000(Ft.)
Slope from curb to property line (v/hz) = 0.020
Gutter width = 2.000(Ft.)
Gutter hike from flowline = 1.920(In.)
Manning's N in gutter = 0.0150
Manning's N from gutter to grade break = 0.0150
Manning's N from grade break to crown = 0.0150
Estimated mean flow rate at midpoint of street =
Depth of flow = 0.571(Ft.), Average velocity = 3
Warning: depth of flow exceeds top of curb
Note: depth of flow exceeds top of street crown.
Distance that curb overflow reaches into property =
Streetflow hydraulics at midpoint of street travel:
Halfstreet flow width = 20.000(Ft.)
Flow velocity = 3.00(Ft/s)
Travel time = 3.19 min. TC = 22.47 min.
Adding area flow to street
000 (Ft
31.588(CFS)
000(Ft/s)
3.55(Ft.)
CONDOMINIUM subarea type
Runoff Coefficient = 0.712
Decimal fraction soil group A = 1.000
Decimal fraction soil group B = 0.000
Decimal fraction soil group C = 0.000
Decimal fraction soil group D = 0.000
RI index for soil(AMC 2) = 32.00
Pervious area fraction = 0.350; Impervious fraction = 0.650
Rainfall intensity = 1.911(In/Hr) for a 10.0 year storm
Subarea runoff = 2.448(CFS) for 1.800(Ac.)
Total runoff = 32.729(CFS) Total area = 19.300(Ac.)
Street flow at end of street = 32.729(CFS)
Half street flow at end of street = 16.365(CFS)
Depth of flow = 0.577(Ft.), Average velocity = 3.029(Ft/s)
Warning: depth of flow exceeds top of curb
Note: depth of flow exceeds top of street crown.
Distance that curb overflow reaches into property = 3.84(Ft.)
Flow width (from curb towards crown)= 20.000(Ft.)
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
Process from Point/Station 12.000 to Point/Station 14.000
**** CONFLUENCE OF MAIN STREAMS ****
The following data inside Main Stream is listed:
In Main Stream number: 1
Stream flow area = 19.300(Ac.)
Runoff from this stream = 32.729(CFS)
Time of concentration = 22.47 min.
Rainfall intensity = 1.911(In/Hr)
Program is now starting with Main Stream No. 2
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
Process from Point/Station 13.000 to Point/Station 14.000
**** INITIAL AREA EVALUATION ****
Initial area flow distance = 800.000(Ft.)
Top (of initial area) elevation = 51.000(Ft.)
Bottom (of initial area) elevation = 45.000(Ft.)
Difference in elevation = 6.000(Ft.)
Slope = 0.00750 s(percent)= 0.75
TC = k(0.370)*[(length^3)/(elevation change)]^0.2
Initial area time of concentration = 14.270 min.
Rainfall intensity = 2.497(In/Hr) for a 10.0
CONDOMINIUM subarea type
Runoff Coefficient = 0.733
Decimal fraction soil group A = 1.000
Decimal fraction soil group B = 0.000
Decimal fraction soil group C = 0.000
Decimal fraction soil group D = 0.000
RI index for soil(AMC 2) = 32.00
Pervious area fraction = 0.350; Impervious fraction
Initial subarea runoff = 4.025(CFS)
Total initial stream area = 2.200(Ac.)
Pervious area fraction = 0.350
year storm
= 0.650
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
Process from Point/Station 13.000 to Point/Station 14.000
**** CONFLUENCE OF MAIN STREAMS ****
The following data inside Main Stream is listed:
In Main Stream number: 2
Stream flow area = 2.200(Ac.)
Runoff from this stream = 4.025(CFS)
Time of concentration = 14.27 min.
Rainfall intensity = 2.497(In/Hr)
Summary of stream data:
Stream Flow rate TC
No. (CFS) (min)
1 32.729 22.47
2 4.025 14.27
Largest stream flow has longer
Qp = 32.729 + sum of
Qb Ia/Ib
4.025 * 0.765 =
Qp = 35.809
Rainfall Intensity
(In/Hr)
1.911
2.497
time of concentration
3.080
Total of 2 main streams to confluence:
Flow rates before confluence point:
32.729 4.025
Area of streams before confluence:
19.300 2.200
Results of confluence:
Total flow rate = 35.809(CFS)
Time of concentration = 22.466 min.
Effective stream area after confluence = 21.500(Ac.)
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
Process from Point/Station 14.000 to Point/Station 16.000
**** STREET FLOW TRAVEL TIME + SUBAREA FLOW ADDITION ****
Top of street segment elevation = 45.000(Ft.)
End of street segment elevation = 42.000(Ft.)
Length of street segment = 725.000(Ft.)
Height of curb above gutter flowline = 6.0(In.)
Width of half street (curb to crown) = 20.000(Ft.)
Distance from crown to crossfall grade break = 18.000(Ft
Slope from gutter to grade break (v/hz) = 0.020
Slope from grade break to crown (v/hz) = 0.020
Street flow is on [2] side(s) of the street
Distance from curb to property line = 13.000(Ft.)
Slope from curb to property line (v/hz) = 0.020
Gutter width = 2.000(Ft.)
Gutter hike from flowline = 1.920(In.)
Manning's N in gutter = 0.0150
Manning's N from gutter to grade break = 0.0150
Manning's N from grade break to crown = 0.0150
Estimated mean flow rate at midpoint of street = 37.195(CFS)
Depth of flow = 0.647(Ft.), Average velocity = 2.585(Ft/s)
Warning: depth of flow exceeds top of curb
Note: depth of flow exceeds top of street crown.
Distance that curb overflow reaches into property = 7.34(Ft.)
Streetflow hydraulics at midpoint of street travel:
Halfstreet flow width = 20.000(Ft.)
Flow velocity = 2.58(Ft/s)
Travel time = 4.67 min. TC = 27.14 min.
Adding area flow to street
CONDOMINIUM subarea type
Runoff Coefficient = 0.704
Decimal fraction soil group A = 1.000
Decimal fraction soil group B = 0.000
Decimal fraction soil group C = 0.000
Decimal fraction soil group D = 0.000
RI index for soil(AMC 2) = 32.00
Pervious area fraction = 0.350; Impervious fraction = 0.650
Rainfall intensity = 1.709(In/Hr) for a 10.0 year storm
Subarea runoff = 2.645(CFS) for 2.200(Ac.)
Total runoff = 38.454(CFS) Total area = 23.700(Ac.)
Street flow at end of street = 38.454(CFS)
Half street flow at end of street = 19.227(CFS)
Depth of flow = 0.653(Ft.), Average velocity = 2.607(Ft/s)
Warning: depth of flow exceeds top of curb
Note: depth of flow exceeds top of street crown.
Distance that curb overflow reaches into property = 7.67(Ft.)
Flow width (from curb towards crown)= 20.000(Ft.)
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
Process from Point/Station 14.000 to Point/Station 16.000
**** CONFLUENCE OF MAIN STREAMS ****
The following data inside Main Stream is listed:
In Main Stream number: 1
Stream flow area = 23.700(Ac.)
Runoff from this stream = 38.454(CFS)
Time of concentration = 27.14 min.
Rainfall intensity = 1.709(In/Hr)
Program is now starting with Main Stream No. 2
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
Process from Point/Station 32.000 to Point/Station 34.000
**** INITIAL AREA EVALUATION ****
Initial area flow distance = 650.000(Ft.)
Top (of initial area) elevation = 56.000(Ft.)
Bottom (of initial area) elevation = 50.000(Ft.)
Difference in elevation = 6.000(Ft.)
Slope = 0.00923 s(percent)= 0.92
TC = k(0.370)*[(length^3)/(elevation change)]^0.2
Initial area time of concentration = 12.599 min.
Rainfall intensity = 2.688(In/Hr) for a 10.0 year storm
CONDOMINIUM subarea type
Runoff Coefficient = 0.738
Decimal fraction soil group A = 1.000
Decimal fraction soil group B = 0.000
Decimal fraction soil group C = 0.000
Decimal fraction soil group D = 0.000
RI index for soil(AMC 2) = 32.00
Pervious area fraction = 0.350; Impervious fraction = 0.650
Initial subarea runoff = 1.985(CFS)
Total initial stream area = 1.000(Ac.)
Pervious area fraction = 0.350
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
Process from Point/Station 34.000 to Point/Station 36.000
**** STREET FLOW TRAVEL TIME + SUBAREA FLOW ADDITION ****
Top of street segment elevation = 50.000(Ft.)
End of street segment elevation = 45.000(Ft.)
Length of street segment = 650.000(Ft.)
Height of curb above gutter flowline = 6.0(In.)
Width of half street (curb to crown) = 20.000(Ft.)
Distance from crown to crossfall grade break = 18.000(Ft.)
Slope from gutter to grade break (v/hz) = 0.020
Slope from grade break to crown (v/hz) = 0.020
Street flow is on [2] side(s) of the street
Distance from curb to property line = 13.000(Ft.)
Slope from curb to property line (v/hz) = 0.020
Gutter width = 2.000(Ft.)
Gutter hike from flowline = 1.920(In.)
Manning's N in gutter = 0.0150
Manning's N from gutter to grade break = 0.0150
Manning's N from grade break to crown = 0.0150
Estimated mean flow rate at midpoint of street = 2.688(CFS)
Depth of flow = 0.280(Ft.), Average velocity = 1.767(Ft/s)
Streetflow hydraulics at midpoint of street travel:
Halfstreet flow width = 8.004(Ft.)
Flow velocity = 1.77(Ft/s)
Travel time = 6.13 min. TC = 18.73 min.
Adding area flow to street
CONDOMINIUM subarea type
Runoff Coefficient = 0.720
Decimal fraction soil group A = 1.000
Decimal fraction soil group B = 0.000
Decimal fraction soil group C = 0.000
Decimal fraction soil group D = 0.000
RI index for soil(AMC 2) = 32.00
Pervious area fraction = 0.350; Impervious fraction = 0.650
Rainfall intensity = 2.127(In/Hr) for a 10.0 year storm
Subarea runoff = 1.225(CFS) for 0.800(Ac.)
Total runoff = 3.210(CFS) Total area = 1.800(Ac.)
Street flow at end of street = 3.210(CFS)
Half street flow at end of street = 1.605(CFS)
Depth of flow = 0.294(Ft.), Average velocity = 1.837(Ft/s)
Flow width (from curb towards crown)= 8.680(Ft.)
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
Process from Point/Station 36.000 to Point/Station 16.000
**** STREET FLOW TRAVEL TIME + SUBAREA FLOW ADDITION ****
Top of street segment elevation = 45.000(Ft.)
End of street segment elevation = 42.000(Ft.)
Length of street segment = 650.000(Ft.)
Height of curb above gutter flowline = 6.0(In.)
Width of half street (curb to crown) = 20.000(Ft.)
Distance from crown to crossfall grade break = 18.000(Ft.)
Slope from gutter to grade break (v/hz) = 0.020
Slope from grade break to crown (v/hz) = 0.020
Street flow is on [2] side(s) of the street
Distance from curb to property line = 13.000(Ft.)
Slope from curb to property line (v/hz) = 0.020
Gutter width = 2.000(Ft.)
Gutter hike from flowline = 1.920(In.)
Manning's N in gutter = 0.0150
Manning's N from gutter to grade break = 0.0150
Manning's N from grade break to crown = 0.0150
Estimated mean flow rate at midpoint of street = 4.601(CFS)
Depth of flow = 0.347(Ft.), Average velocity = 1.639(Ft/s)
Streetflow hydraulics at midpoint of street travel:
Halfstreet flow width = 11.331(Ft.)
Flow velocity = 1.64(Ft/s)
Travel time = 6.61 min. TC = 25.34 min.
Adding area flow to street
CONDOMINIUM subarea type
Runoff Coefficient = 0.707
Decimal fraction soil group A = 1.000
Decimal fraction soil group B = 0.000
Decimal fraction soil group C = 0.000
Decimal fraction soil group D = 0.000
RI index for soil(AMC 2) = 32.00
Pervious area fraction = 0.350; Impervious fraction = 0.650
Rainfall intensity = 1.780(In/Hr) for a 10.0 year storm
Subarea runoff = 2.641(CFS) for 2.100(Ac.)
Total runoff = 5.851(CFS) Total area = 3.900(Ac.)
Street flow at end of street = 5.851(CFS)
Half street flow at end of street = 2.925(CFS)
Depth of flow = 0.370(Ft.), Average velocity = 1.734(Ft/s)
Flow width (from curb towards crown)= 12.517(Ft.)
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
Process from Point/Station 36.000 to Point/Station 16.000
**** CONFLUENCE OF MAIN STREAMS ****
The following data inside Main Stream is listed:
In Main Stream number: 2
Stream flow area = 3.900(Ac.)
Runoff from this stream = 5.851(CFS)
Time of concentration = 25.34 min.
Rainfall intensity = 1.780(In/Hr)
Program is now starting with Main Stream No. 3
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
Process from Point/Station 20.000 to Point/Station 22.000
**** INITIAL AREA EVALUATION ****
Initial area flow distance = 650.000(Ft.)
Top (of initial area) elevation = 55.000(Ft.)
Bottom (of initial area) elevation = 51.000(Ft.)
Difference in elevation = 4.000(Ft.)
Slope = 0.00615 s(percent)= 0.62
TC = k(0.370)*[(length^3)/(elevation change)]^0.2
Initial area time of concentration = 13.663 min.
Rainfall intensity = 2.562(In/Hr) for a 10.0 year storm
CONDOMINIUM subarea type
Runoff Coefficient = 0.735
Decimal fraction soil group A = 1.000
Decimal fraction soil group B = 0.000
Decimal fraction soil group C = 0.000
Decimal fraction soil group D = 0.000
RI index for soil(AMC 2) = 32.00
Pervious area fraction = 0.350; Impervious fraction = 0.650
Initial subarea runoff = 6.776(CFS)
Total initial stream area = 3.600(Ac.)
Pervious area fraction = 0.350
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
Process from Point/Station 22.000 to Point/Station 26.000
**** STREET FLOW TRAVEL TIME + SUBAREA FLOW ADDITION ****
Top of street segment elevation = 51.000(Ft.)
End of street segment elevation = 46.000(Ft.)
Length of street segment = 550.000(Ft.)
Height of curb above gutter flowline = 6.0(In.)
Width of half street (curb to crown) = 16.000(Ft.)
Distance from crown to crossfall grade break = 14.000(Ft.)
Slope from gutter to grade break (v/hz) = 0.020
Slope from grade break to crown (v/hz) = 0.020
Street flow is on [2] side(s) of the street
Distance from curb to property line = 10.000(Ft.)
Slope from curb to property line (v/hz) = 0.020
Gutter width = 2.000(Ft.)
Gutter hike from flowline = 1.920(In.)
Manning's N in gutter = 0.0150
Manning's N from gutter to grade break = 0.0150
Manning's N from grade break to crown = 0.0150
Estimated mean flow rate at midpoint of street = 11.246(CFS)
Depth of flow = 0.404(Ft.), Average velocity = 2.624(Ft/s)
Streetflow hydraulics at midpoint of street travel:
Halfstreet flow width = 14.223(Ft.)
Flow velocity = 2.62(Ft/s)
Travel time = 3.49 min. TC = 17.16 min.
Adding area flow to street
CONDOMINIUM subarea type
Runoff Coefficient = 0.724
Decimal fraction soil group A = 1.000
Decimal fraction soil group B = 0.000
Decimal fraction soil group C = 0.000
Decimal fraction soil group D = 0.000
RI index for soil(AMC 2) = 32.00
Pervious area fraction = 0.350; Impervious fraction = 0.650
Rainfall intensity = 2.240(In/Hr) for a 10.0 year storm
Subarea runoff = 8.759(CFS) for 5.400(Ac.)
Total runoff = 15.536(CFS) Total area = 9.000(Ac.)
Street flow at end of street = 15.536(CFS)
Half street flow at end of street = 7.768(CFS)
Depth of flow = 0.443(Ft.), Average velocity = 2.849(Ft/s)
Note: depth of flow exceeds top of street crown.
Flow width (from curb towards crown)= 16.000(Ft.)
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
Process from Point/Station 24.000 to Point/Station 26.000
**** SUBAREA FLOW ADDITION ****
UNDEVELOPED (good cover) subarea
Runoff Coefficient = 0.457
Decimal fraction soil group A = 1.000
Decimal fraction soil group B = 0.000
Decimal fraction soil group C = 0.000
Decimal fraction soil group D = 0.000
RI index for soil(AMC 2) = 38.00
Pervious area fraction = 1.000; Impervious fraction = 0.000
Time of concentration = 17.16 min.
Rainfall intensity = 2.240(In/Hr) for a 10.0 year storm
Subarea runoff = 6.853(CFS) for 6.700(Ac.)
Total runoff = 22.389(CFS) Total area = 15.700(Ac.)
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
Process from Point/Station 26.000 to Point/Station 28.000
**** STREET FLOW TRAVEL TIME + SUBAREA FLOW ADDITION ****
Top of street segment elevation = 46.000(Ft.)
End of street segment elevation = 43.000(Ft.)
Length of street segment = 550.000(Ft.)
Height of curb above gutter flowline = 6.0(In.)
Width of half street (curb to crown) = 20.000(Ft.)
Distance from crown to crossfall grade break = 18.
Slope from gutter to grade break (v/hz) = 0.020
Slope from grade break to crown (v/hz) = 0.020
Street flow is on [2] side(s) of the street
Distance from curb to property line = 13.000(Ft.)
Slope from curb to property line (v/hz) = 0.020
Gutter width = 2.000(Ft.)
Gutter hike from flowline = 1.920(In.)
Manning's N in gutter = 0.0150
Manning's N from gutter to grade break = 0.0150
Manning's N from grade break to crown = 0.0150
Estimated mean flow rate at midpoint of street =
Depth of flow = 0.546(Ft.), Average velocity = 2
Warning: depth of flow exceeds top of curb
Note: depth of flow exceeds top of street crown.
Distance that curb overflow reaches into property =
Streetflow hydraulics at midpoint of street travel:
Halfstreet flow width = 20.000(Ft.)
000 (Ft
23.958(CFS)
551(Ft/s)
2.31 (Ft.)
Flow velocity = 2.55(Ft/s)
Travel time = 3.59 min. TC = 20.75 min.
Adding area flow to street
CONDOMINIUM subarea type
Runoff Coefficient = 0.715
Decimal fraction soil group A = 1.000
Decimal fraction soil group B = 0.000
Decimal fraction soil group C = 0.000
Decimal fraction soil group D = 0.000
RI index for soil(AMC 2) = 32.00
Pervious area fraction = 0.350; Impervious fraction
Rainfall intensity = 2.002(In/Hr) for a 10.0
Subarea runoff = 3.152(CFS) for 2.200(Ac.)
Total runoff = 25.541(CFS) Total area =
Street flow at end of street = 25.541(CFS)
Half street flow at end of street = 12.770(CFS)
Depth of flow = 0.556(Ft.), Average velocity = 2
Warning: depth of flow exceeds top of curb
Note: depth of flow exceeds top of street crown.
Distance that curb overflow reaches into property =
Flow width (from curb towards crown)= 20.000(Ft.)
= 0.650
year storm
17.900(Ac.)
594(Ft/s)
2.81(Ft.)
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
Process from Point/Station 28.000 to Point/Station 16.000
**** STREET FLOW TRAVEL TIME + SUBAREA FLOW ADDITION ****
Top of street segment elevation = 43.000(Ft.)
End of street segment elevation = 42.000(Ft.)
Length of street segment = 300.000(Ft.)
Height of curb above gutter flowline = 6.0(In.)
Width of half street (curb to crown) = 40.000(Ft.)
Distance from crown to crossfall grade break = 38.
Slope from gutter to grade break (v/hz) = 0.020
Slope from grade break to crown (v/hz) = 0.020
Street flow is on [2] side(s) of the street
Distance from curb to property line = 12.000(Ft.)
Slope from curb to property line (v/hz) = 0.020
Gutter width = 2.000(Ft.)
Gutter hike from flowline = 1.920(In.)
Manning's N in gutter = 0.0150
Manning's N from gutter to grade break = 0.0150
Manning's N from grade break to crown = 0.0150
Estimated mean flow rate at midpoint of street =
Depth of flow = 0.616(Ft.), Average velocity = 2
Warning: depth of flow exceeds top of curb
Distance that curb overflow reaches into property =
Streetflow hydraulics at midpoint of street travel:
Halfstreet flow width = 24.822(Ft.)
Flow velocity = 2.04(Ft/s)
Travel time = 2.45 min. TC = 23.21 min.
Adding area flow to street
CONDOMINIUM subarea type
Runoff Coefficient = 0.710
Decimal fraction soil group A = 1.000
Decimal fraction soil group B = 0.000
Decimal fraction soil group C = 0.000
000 (Ft
26.968(CFS)
037(Ft/s)
5.82(Ft.)
Decimal fraction soil group D = 0.000
RI index for soil(AMC 2) = 32.00
Pervious area fraction = 0.350; Impervious fraction = 0.650
Rainfall intensity = 1.875(In/Hr) for a 10.0 year storm
Subarea runoff = 2.664(CFS) for 2.000(Ac.)
Total runoff = 28.204(CFS) Total area = 19.900(Ac.)
Street flow at end of street = 28.204(CFS)
Half street flow at end of street = 14.102(CFS)
Depth of flow = 0.625(Ft.), Average velocity = 2.052(Ft/s)
Warning: depth of flow exceeds top of curb
Distance that curb overflow reaches into property = 6.23(Ft.)
Flow width (from curb towards crown)= 25.226(Ft.)
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
Process from Point/Station 28.000 to Point/Station 16.000
**** CONFLUENCE OF MAIN STREAMS ****
The following data inside Main Stream is listed:
In Main Stream number: 3
Stream flow area = 19.900(Ac.)
Runoff from this stream = 28.204(CFS)
Time of concentration = 23.21 min.
Rainfall intensity = 1.875(In/Hr)
Summary of stream data:
Stream
Flow rate
TC
Rainfall Intensity
No.
(CFS)
(min)
(In/Hr)
1
38.454
27.14
1.709
2
5.851
25.34
1.780
3
28.204
23.21
1.875
Largest
stream flow
has longer
time of concentration
Qp =
38.454 +
sum of
Qb
Ia/Ib
5.851 *
0.960 =
5.618
Qb
Ia/Ib
28.204 *
0.912 =
25.714
Qp =
69.787
Total of 3 main streams to confluence:
Flow rates before confluence point:
38.454 5.851 28.204
Area of streams before confluence:
23.700 3.900 19.900
Results of confluence:
Total flow rate = 69.787(CFS)
Time of concentration = 27.140 min.
Effective stream area after confluence = 47.500(Ac.)
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
Process from Point/Station 16.000 to Point/Station 38.000
**** STREET FLOW TRAVEL TIME + SUBAREA FLOW ADDITION ****
Top of street segment elevation = 42.000(Ft.)
End of street segment elevation = 40.000(Ft.)
Length of street segment = 200.000(Ft.)
Height of curb above gutter flowline = 6.0(In.)
Width of half street (curb to crown) = 40.000(Ft.)
Distance from crown to crossfall grade break = 38.000(Ft
Slope from gutter to grade break (v/hz) = 0.020
Slope from grade break to crown (v/hz) = 0.020
Street flow is on [2] side(s) of the street
Distance from curb to property line = 12.000(Ft.)
Slope from curb to property line (v/hz) = 0.020
Gutter width = 2.000(Ft.)
Gutter hike from flowline = 1.920(In.)
Manning's N in gutter = 0.0150
Manning's N from gutter to grade break = 0.0150
Manning's N from grade break to crown = 0.0150
Estimated mean flow rate at midpoint of street =
Depth of flow = 0.693(Ft.), Average velocity = 3.
Warning: depth of flow exceeds top of curb
Distance that curb overflow reaches into property =
Streetflow hydraulics at midpoint of street travel:
Halfstreet flow width = 28.634(Ft.)
Flow velocity = 3.81(Ft/s)
Travel time = 0.88 min. TC = 28.02 min.
Adding area flow to street
CONDOMINIUM subarea type
Runoff Coefficient = 0.702
Decimal fraction soil group A = 1.000
Decimal fraction soil group B = 0.000
Decimal fraction soil group C = 0.000
Decimal fraction soil group D = 0.000
RI index for soil(AMC 2) = 32.00
Pervious area fraction = 0.350; Impervious fraction
Rainfall intensity = 1.677(In/Hr) for a 10.0
Subarea runoff = 1.178(CFS) for 1.000(Ac.)
Total runoff = 70.965(CFS) Total area =
Street flow at end of street = 70.965(CFS)
Half street flow at end of street = 35.482(CFS)
Depth of flow = 0.694(Ft.), Average velocity = 3.
Warning: depth of flow exceeds top of curb
Distance that curb overflow reaches into property =
Flow width (from curb towards crown)= 28.704(Ft.)
End of computations, total study area = 48.
The following figures may
be used for a unit hydrograph study of the same area.
Area averaged pervious area fraction(Ap) = 0.440
Area averaged RI index number = 32.8
70.449(CFS)
809(Ft/s)
9.63(Ft.)
= 0.650
year storm
48.500(Ac.)
815(Ft/s)
9.70(Ft.)
50 (Ac.)
b. STUDY AREA RUNOFF HYDROLOGIC CALCULATIONS
M:\1LAQ010102\ENGR\DESIGN\HYDR\Drainage Study Report.doc
Riverside County Rational Hydrology Program
CIVILCADD/CIVILDESIGN Engineering Software,(c) 1989 - 2005 Version 7.1
Rational Hydrology Study Date: 12/13/07 File:lagl0yr.out
----------------------------------------------------------------------
********* Hydrology Study Control Information **********
English (in -lb) Units used in input data file
----------------------------------------------------------------------
Study Area -Downtown, 10 -yr Storm
Program License Serial Number 6124
----------------------------------------------------------------------
Rational Method Hydrology Program based on
Riverside County Flood Control & Water Conservation District
1978 hydrology manual
Storm event (year) = 10.00 Antecedent Moisture Condition = 2
2 year, 1 hour precipitation = 0.700(In.)
100 year, 1 hour precipitation = 1.600(In.)
Storm event year = 10.0
Calculated rainfall intensity data:
1 hour intensity = 1.070(In/Hr)
Slope of intensity duration curve = 0.5900
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
Process from Point/Station 50.000 to Point/Station 52.000
**** INITIAL AREA EVALUATION ****
Initial area flow distance = 600.000(Ft.)
Top (of initial area) elevation = 56.000(Ft.)
Bottom (of initial area) elevation = 51.000(Ft.)
Difference in elevation = 5.000(Ft.)
Slope = 0.00833 s(percent)= 0.83
TC = k(0.370)*[(length^3)/(elevation change)]^0.2
Initial area time of concentration = 12.454 min.
Rainfall intensity = 2.706(In/Hr) for a 10.0 year storm
CONDOMINIUM subarea type
Runoff Coefficient = 0.739
Decimal fraction soil group A = 1.000
Decimal fraction soil group B = 0.000
Decimal fraction soil group C = 0.000
Decimal fraction soil group D = 0.000
RI index for soil(AMC 2) = 32.00
Pervious area fraction = 0.350; Impervious fraction = 0.650
Initial subarea runoff = 7.999(CFS)
Total initial stream area = 4.000(Ac.)
Pervious area fraction = 0.350
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
Process from Point/Station 52.000 to Point/Station 54.000
**** STREET FLOW TRAVEL TIME + SUBAREA FLOW ADDITION ****
Top of street segment elevation = 51.000(Ft.)
End of street segment elevation = 47.000(Ft.)
Length of street segment = 400.000(Ft.)
Height of curb above gutter flowline = 6.0(In.)
Width of half street (curb to crown) = 16.000(Ft.)
Distance from crown to crossfall grade break = 14.
Slope from gutter to grade break (v/hz) = 0.020
Slope from grade break to crown (v/hz) = 0.020
Street flow is on [2] side(s) of the street
Distance from curb to property line = 10.000(Ft.)
Slope from curb to property line (v/hz) = 0.020
Gutter width = 2.000(Ft.)
Gutter hike from flowline = 1.920(In.)
Manning's N in gutter = 0.0150
Manning's N from gutter to grade break = 0.0150
Manning's N from grade break to crown = 0.0150
Estimated mean flow rate at midpoint of street =
Depth of flow = 0.412(Ft.), Average velocity = 2
Streetflow hydraulics at midpoint of street travel:
Halfstreet flow width = 14.613(Ft.)
Flow velocity = 2.80(Ft/s)
Travel time = 2.38 min. TC = 14.84 min.
Adding area flow to street
CONDOMINIUM subarea type
Runoff Coefficient = 0.731
Decimal fraction soil group A = 1.000
Decimal fraction soil group B = 0.000
Decimal fraction soil group C = 0.000
Decimal fraction soil group D = 0.000
RI index for soil(AMC 2) = 32.00
Pervious area fraction = 0.350; Impervious fraction
Rainfall intensity = 2.441(In/Hr) for a 10.0
Subarea runoff = 9.096(CFS) for 5.100(Ac.)
Total runoff = 17.095(CFS) Total area =
Street flow at end of street = 17.095(CFS)
Half street flow at end of street = 8.547(CFS)
Depth of flow = 0.448(Ft.), Average velocity = 3
Note: depth of flow exceeds top of street crown.
Flow width (from curb towards crown)= 16.000(Ft.)
000 (Ft
12.617(CFS)
797(Ft/s)
= 0.650
year storm
9.100(Ac.)
046(Ft/s)
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
Process from Point/Station 54.000 to Point/Station 56.000
**** STREET FLOW TRAVEL TIME + SUBAREA FLOW ADDITION ****
Top of street segment elevation = 47.000(Ft.)
End of street segment elevation = 45.000(Ft.)
Length of street segment = 250.000(Ft.)
Height of curb above gutter flowline = 6.0(In.)
Width of half street (curb to crown) = 20.000(Ft.)
Distance from crown to crossfall grade break = 18.000(Ft
Slope from gutter to grade break (v/hz) = 0.020
Slope from grade break to crown (v/hz) = 0.020
Street flow is on [2] side(s) of the street
Distance from curb to property line = 13.000(Ft.)
Slope from curb to property line (v/hz) = 0.020
Gutter width = 2.000(Ft.)
Gutter hike from flowline = 1.920(In.)
Manning's N in gutter = 0.0150
Manning's N from gutter to grade break = 0.0150
Manning's N from grade break to crown = 0.0150
Estimated mean flow rate at midpoint of street =
Depth of flow = 0.485(Ft.), Average velocity = 2
Streetflow hydraulics at midpoint of street travel:
Halfstreet flow width = 18.245(Ft.)
Flow velocity = 2.87(Ft/s)
Travel time = 1.45 min. TC = 16.29 min.
Adding area flow to street
CONDOMINIUM subarea type
Runoff Coefficient = 0.726
Decimal fraction soil group A = 1.000
Decimal fraction soil group B = 0.000
Decimal fraction soil group C = 0.000
Decimal fraction soil group D = 0.000
RI index for soil(AMC 2) = 32.00
Pervious area fraction = 0.350; Impervious fraction
Rainfall intensity = 2.310(In/Hr) for a 10.0
Subarea runoff = 5.202(CFS) for 3.100(Ac.)
Total runoff = 22.296(CFS) Total area =
Street flow at end of street = 22.296(CFS)
Half street flow at end of street = 11.148(CFS)
19.773(CFS)
867(Ft/s)
= 0.650
year storm
12.200(Ac.)
Depth of flow = 0.503(Ft.), Average velocity = 2.941(Ft/s)
Warning: depth of flow exceeds top of curb
Distance that curb overflow reaches into property = 0.16(Ft.)
Flow width (from curb towards crown)= 19.159(Ft.)
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
Process from Point/Station 56.000 to Point/Station 58.000
**** STREET FLOW TRAVEL TIME + SUBAREA FLOW ADDITION ****
Top of street segment elevation = 45.000(Ft.)
End of street segment elevation = 43.000(Ft.)
Length of street segment = 400.000(Ft.)
Height of curb above gutter flowline = 6.0(In.)
Width of half street (curb to crown) = 20.000(Ft.)
Distance from crown to crossfall grade break = 18.000(Ft.)
Slope from gutter to grade break (v/hz) = 0.020
Slope from grade break to crown (v/hz) = 0.020
Street flow is on [2] side(s) of the street
Distance from curb to property line = 13.000(Ft.)
Slope from curb to property line (v/hz) = 0.020
Gutter width = 2.000(Ft.)
Gutter hike from flowline = 1.920(In.)
Manning's N in gutter = 0.0150
Manning's N from gutter to grade break = 0.0150
Manning's N from grade break to crown = 0.0150
Estimated mean flow rate at midpoint of street = 26.457(CFS)
Depth of flow = 0.569(Ft.), Average velocity = 2.536(Ft/s)
Warning: depth of flow exceeds top of curb
Note: depth of flow exceeds top of street crown.
Distance that curb overflow reaches into property =
3.45(Ft.)
Streetflow hydraulics at midpoint of street travel:
Halfstreet flow width = 20.000(Ft.)
Flow velocity = 2.54(Ft/s)
Travel time = 2.63 min. TC = 18.92 min.
Adding area flow to street
CONDOMINIUM subarea type
Runoff Coefficient = 0.720
Decimal fraction soil group A = 1.000
Decimal fraction soil group B = 0.000
Decimal fraction soil group C = 0.000
Decimal fraction soil group D = 0.000
RI index for soil(AMC 2) = 32.00
Pervious area fraction = 0.350; Impervious fraction
= 0.650
Rainfall intensity = 2.115(In/Hr) for a 10.0
year storm
Subarea runoff = 8.217(CFS) for 5.400(Ac.)
Total runoff = 30.513(CFS) Total area =
17.600(Ac.)
Street flow at end of street = 30.513(CFS)
Half street flow at end of street = 15.257(CFS)
Depth of flow = 0.593(Ft.), Average velocity = 2.632(Ft/s)
Warning: depth of flow exceeds top of curb
Note: depth of flow exceeds top of street crown.
Distance that curb overflow reaches into property =
4.65(Ft.)
Flow width (from curb towards crown)= 20.000(Ft.)
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
Process from Point/Station 58.000 to Point/Station 60.000
**** STREET FLOW TRAVEL TIME + SUBAREA FLOW ADDITION ****
Top of street segment elevation = 43.000(Ft.)
End of street segment elevation = 42.000(Ft.)
Length of street segment = 300.000(Ft.)
Height of curb above gutter flowline = 6.0(In.)
Width of half street (curb to crown) = 20.000(Ft.)
Distance from crown to crossfall grade break = 18.000(Ft.)
Slope from gutter to grade break (v/hz) = 0.020
Slope from grade break to crown (v/hz) = 0.020
Street flow is on [2] side(s) of the street
Distance from curb to property line = 13.000(Ft.)
Slope from curb to property line (v/hz) = 0.020
Gutter width = 2.000(Ft.)
Gutter hike from flowline = 1.920(In.)
Manning's N in gutter = 0.0150
Manning's N from gutter to grade break = 0.0150
Manning's N from grade break to crown = 0.0150
Estimated mean flow rate at midpoint of street = 33.429(CFS)
Depth of flow = 0.647(Ft.), Average velocity = 2.321(Ft/s)
Warning: depth of flow exceeds top of curb
Note: depth of flow exceeds top of street crown.
Distance that curb overflow reaches into property = 7.35(Ft.)
Streetflow hydraulics at midpoint of street travel:
Halfstreet flow width = 20.000(Ft.)
Flow velocity = 2.32(Ft/s)
Travel time = 2.15 min. TC = 21.07
Adding area flow to street
CONDOMINIUM subarea type
Runoff Coefficient = 0.715
Decimal fraction soil group A = 1.000
Decimal fraction soil group B = 0.000
Decimal fraction soil group C = 0.000
Decimal fraction soil group D = 0.000
RI index for soil(AMC 2) = 32.00
Pervious area fraction = 0.350; Impervious
Rainfall intensity = 1.984(In/Hr) for a
Subarea runoff = 5.673(CFS) for 4.
min.
fraction
10.0
000(Ac.)
Total runoff = 36.186(CFS) Total area =
Street flow at end of street = 36.186(CFS)
Half street flow at end of street = 18.093(CFS)
Depth of flow = 0.663(Ft.), Average velocity =
Warning: depth of flow exceeds top of curb
Note: depth of flow exceeds top of street crown.
Distance that curb overflow reaches into property =
Flow width (from curb towards crown)= 20.000(Ft.)
= 0.650
year storm
21.600(Ac.)
2.369(Ft/s)
8.14(Ft.)
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
Process from Point/Station 60.000 to Point/Station 62.000
**** STREET FLOW TRAVEL TIME + SUBAREA FLOW ADDITION ****
Top of street segment elevation = 42.000(Ft.)
End of street segment elevation = 40.000(Ft.)
Length of street segment = 400.000(Ft.)
Height of curb above gutter flowline = 6.0(In.)
Width of half street (curb to crown) = 20.000(Ft.)
Distance from crown to crossfall grade break = 18.
Slope from gutter to grade break (v/hz) = 0.020
Slope from grade break to crown (v/hz) = 0.020
Street flow is on [2] side(s) of the street
Distance from curb to property line = 13.000(Ft.)
Slope from curb to property line (v/hz) = 0.020
Gutter width = 2.000(Ft.)
Gutter hike from flowline = 1.920(In.)
Manning's N in gutter = 0.0150
Manning's N from gutter to grade break = 0.0150
Manning's N from grade break to crown = 0.0150
Estimated mean flow rate at midpoint of street =
Depth of flow = 0.637(Ft.), Average velocity = 2
Warning: depth of flow exceeds top of curb
Note: depth of flow exceeds top of street crown.
Distance that curb overflow reaches into property =
Streetflow hydraulics at midpoint of street travel:
Halfstreet flow width = 20.000(Ft.)
Flow velocity = 2.81(Ft/s)
Travel time = 2.38 min. TC = 23.45 min.
Adding area flow to street
CONDOMINIUM subarea type
Runoff Coefficient = 0.710
Decimal fraction soil group A = 1.000
Decimal fraction soil group B = 0.000
Decimal fraction soil group C = 0.000
000 (Ft
38.920(CFS)
805(Ft/s)
6.86(Ft.)
Decimal fraction soil group D = 0.000
RI index for soil(AMC 2) = 32.00
Pervious area fraction = 0.350; Impervious fraction = 0.650
Rainfall intensity = 1.863(In/Hr) for a 10.0 year storm
Subarea runoff = 5.291(CFS) for 4.000(Ac.)
Total runoff = 41.477(CFS) Total area = 25.600(Ac.)
Street flow at end of street = 41.477(CFS)
Half street flow at end of street = 20.738(CFS)
Depth of flow = 0.650(Ft.), Average velocity = 2.852(Ft/s)
Warning: depth of flow exceeds top of curb
Note: depth of flow exceeds top of street crown.
Distance that curb overflow reaches into property = 7.48(Ft.)
Flow width (from curb towards crown)= 20.000(Ft.)
End of computations, total study area = 25.60 (Ac.)
The following figures may
be used for a unit hydrograph study of the same area.
Area averaged pervious area fraction(Ap) = 0.350
Area averaged RI index number = 32.0
c. STREETS AND CATCH BASIN CAPACITIES
M:\1LAQ010102\ENGR\DESIGN\HYDR\Drainage Study Report.doc
AVENIDA BERMUDAS CAPACITY
M:\1LAQ010102\ENGR\DESIGN\HYDR\Drainage Study Report.doc
CIVILCADD/CIVILDESIGN Engineering Software, (c) 2004 Version 7.0
--------------------------------------------------------------------
Program License Serial Number 6124
*** Street Flow Analysis ***
AVENIDA BERMUDAS
Upstream (headworks) Elevation = 0.710(Ft.)
Downstream (outlet) Elevation = 0.000(Ft.)
Runoff/Flow Distance = 100.000(Ft.)
Maximum flow rate in channel(s) = 44.400(CFS)
--------------------------------------------------------------------
Top of street segment elevation = 0.710(Ft.)
End of street segment elevation = 0.000(Ft.)
Length of street segment = 100.000(Ft.)
Height of curb above gutter flowline = 6.0(In.)
Width of half street (curb to crown) = 32.000(Ft.)
Distance from crown to crossfall grade break = 20.000(Ft
Slope from gutter to grade break (v/hz) = 0.020
Slope from grade break to crown (v/hz) = 0.020
Street flow is on [2] side(s) of the street
Distance from curb to property line = 12.000(Ft.)
Slope from curb to property line (v/hz) = 0.020
Gutter width = 2.000(Ft.)
Gutter hike from flowline = 1.920(In.)
Manning's N in gutter = 0.0150
Manning's N from gutter to grade break = 0.0150
Manning's N from grade break to crown = 0.0150
Half street cross section data points:
X-coordinate (Ft.) Y-coordinate (Ft.)
0.0000 0.7400 right of way
12.0000 0.5000 top of curb
12.0000 0.0000 flow line
14.0000 0.1600 gutter end
24.0000 0.3600 grade break
44.0000 0.7600 crown
Depth of flow = 0.638(Ft.)
Average velocity = 3.036(Ft/s)
Total flow rate in 1/2 street = 22.200(CFS)
Warning: depth of flow exceeds top of curb
Distance that curb overflow reaches into property = 6.91(Ft.)
Streetflow hydraulics:
Halfstreet flow width (curb to crown) = 25.912(Ft.)
Average flow velocity = 3.04(Ft/s)
Channel including Gutter and area towards property line:
Flow Width = 8.912(Ft.) Flow Area = 1.594(Sq.Ft)
Velocity = 2.275(Ft/s) Flow Rate = 3.627(CFS)
Froude No. = 0.9480
Channel from outside edge of gutter towards grade break:
Flow Width = 10.000(Ft.) Flow Area = 3.782(Sq.Ft)
Velocity = 3.889(Ft/s) Flow Rate = 14.709(CFS)
Froude No. = 1.1143
Channel from grade break to crown:
Flow Width = 13.912(Ft.) Flow Area = 1.935(Sq.Ft)
Velocity = 1.996(Ft/s) Flow Rate = 3.864(CFS)
Froude No. = 0.9432
Total flow rate in street = 44.400(CFS)
DESERT CLUB DRIVE CAPACITY
M:\1LAQ010102\ENGR\DESIGN\HYDR\Drainage Study Report.doc
CIVILCADD/CIVILDESIGN Engineering Software, (c) 2004 Version 7.0
--------------------------------------------------------------------
Program License Serial Number 6124
------------------------------------------------------------------
*** Street Flow Analysis ***
DESERT CLUB DRIVE
Upstream (headworks) Elevation = 0.500(Ft.)
Downstream (outlet) Elevation = 0.000(Ft.)
Runoff/Flow Distance = 100.000(Ft.)
Maximum flow rate in channel(s) = 41.500(CFS)
------------------------------------------------------------------
Top of street segment elevation = 0.500(Ft.)
End of street segment elevation = 0.000(Ft.)
Length of street segment = 100.000(Ft.)
Height of curb above gutter flowline = 6.0(In.)
Width of half street (curb to crown) = 20.000(Ft.)
Distance from crown to crossfall grade break = 12.000(Ft.)
Slope from gutter to grade break (v/hz) = 0.020
Slope from grade break to crown (v/hz) = 0.020
Street flow is on [2] side(s) of the street
Distance from curb to property line = 12.000(Ft.)
Slope from curb to property line (v/hz) = 0.020
Gutter width = 2.000(Ft.)
Gutter hike from flowline = 1.920(In.)
Manning's N in gutter = 0.0150
Manning's N from gutter to grade break = 0.0150
Manning's N from grade break to crown = 0.0150
Half street cross section data points:
X-coordinate (Ft.) Y-coordinate (Ft.)
0.0000 0.7400 right of way
12.0000 0.5000 top of curb
12.0000 0.0000 flow line
14.0000 0.1600 gutter end
20.0000 0.2800 grade break
32.0000 0.5200 crown
Depth of flow = 0.650(Ft.)
Average velocity = 2.852(Ft/s)
Total flow rate in 1/2 street = 20.750(CFS)
Warning: depth of flow exceeds top of curb
Note: depth of flow exceeds top of street crown.
Distance that curb overflow reaches into property = 7.49(Ft.)
Streetflow hydraulics:
Halfstreet flow width (curb to crown) = 20.000(Ft.)
Average flow velocity = 2.85(Ft/s)
Channel including Gutter and area towards property line:
Flow Width = 9.486(Ft.) Flow Area = 1.700(Sq.Ft)
Velocity = 2.004(Ft/s) Flow Rate = 3.407(CFS)
Froude No. = 0.8345
Channel from outside edge of gutter towards grade break:
Flow Width = 6.000(Ft.) Flow Area = 2.578(Sq.Ft)
Velocity = 3.718(Ft/s) Flow Rate = 9.585(CFS)
Froude No. = 0.9994
Channel from grade break to crown:
Flow Width = 12.000(Ft.) Flow Area = 2.997(Sq.Ft)
Velocity = 2.589(Ft/s) Flow Rate = 7.758(CFS)
Froude No. = 0.9130
Total flow rate in street = 41.500(CFS)
CALLE TAMPICO AND CATCH BASIN CAPACITIES
M:\1LAQ010102\ENGR\DESIGN\HYDR\Drainage Study Report.doc
CIVILCADD/CIVILDESIGN Engineering Software, (c) 2004 Version 7.0
--------------------------------------------------------------------
Program License Serial Number 6124
------------------------------------------------------------------
*** Street Flow +Inlet Analysis ***
CALLE TAMPICO
Upstream (headworks) Elevation = 0.120(Ft.)
Downstream (outlet) Elevation = 0.000(Ft.)
Runoff/Flow Distance = 100.000(Ft.)
Maximum flow rate in channel(s) = 71.000(CFS)
--------------------------------------------------------------------
Top of street segment elevation = 0.120(Ft.)
End of street segment elevation = 0.000(Ft.)
Length of street segment = 100.000(Ft.)
Height of curb above gutter flowline = 6.0(In.)
Width of half street (curb to crown) = 40.000(Ft.)
Distance from crown to crossfall grade break = 38.000(Ft.)
Slope from gutter to grade break (v/hz) = 0.020
Slope from grade break to crown (v/hz) = 0.020
Street flow is on [1] side(s) of the street
Distance from curb to property line = 12.000(Ft.)
Slope from curb to property line (v/hz) = 0.020
Gutter width = 2.000(Ft.)
Gutter hike from flowline = 1.920(In.)
Manning's N in gutter = 0.0150
Manning's N from gutter to grade break = 0.0150
Manning's N from grade break to crown = 0.0150
Half street cross section data points:
X-coordinate (Ft.)
Y-coordinate (Ft.)
0.0000
0.7400
right of way
12.0000
0.5000
top of curb
12.0000
0.0000
flow line
14.0000
0.1600
gutter end
14.0000
0.1600
grade break
52.0000
0.9200
crown
CURB INLET TYPE STREET DRAIN, Opening Height = 8.000(In.)
Street Inlet Calculations:
Street flow in street inlet depression = 71.000(CFS)
Gutter depression depth = 4.000(In.)
Gutter depression width = 2.000(Ft.)
Depth of flow = 1.447(Ft.)
Average velocity = 2.357(Ft/s)
Total flow rate in 1/2 street = 71.000(CFS)
!!Warning: Water is above left or right bank elevations
U.S. DOT Hydraulic Engineering Circular No. 12 inlet calculations:
Street flow half width at start of inlet = 40.000(Ft.)
Flow rate in gutter section of street = Qw = 19.376(CFS)
Given inlet length L = 7.000(Ft.)
Ratio of frontal flow to total flow = EO = 0.2729
Street slope is less than 0.5% ,
Depth of flow indicates an orifice flow
condition exists for an opening height of 8.00(In.)
Using equation Qi = .67hL(2gd0)^.5
Maximum inlet flow capacity = 26.478(CFS)
Half street cross section data points through curb inlet:
X-coordinate (Ft.) Y-coordinate (Ft.)
0.0000 1.0733 right of way
12.0000 0.8333 top of curb
12.0000 0.0000 flow line
14.0000 0.4933 gutter/depression end
14.0000 0.4933 grade break
52.0000 1.2533 crown
Remaining flow in street below inlets = 44.522(CFS)
Depth of flow = 0.977(Ft.)
Average velocity = 1.962(Ft/s)
Total flow rate in 1/2 street = 44.522(CFS)
!!Warning: Water is above left or right bank elevations
Warning: depth of flow exceeds top of curb
Note: depth of flow exceeds top of street crown.
Distance that curb overflow reaches into property = 23.86(Ft.)
Streetflow hydraulics:
Halfstreet flow width (curb to crown) = 40.000(Ft.)
Average flow velocity = 1.96(Ft/s)
Channel including Gutter and area towards property line:
Flow Width = 14.000(Ft.) Flow Area = 6.081(Sq.Ft)
Velocity = 1.922(Ft/s) Flow Rate = 11.686(CFS)
Froude No. = 0.5138
Channel from outside edge of gutter towards grade break:
Flow Width = 0.000(Ft.) Flow Area = 0.000(Sq.Ft)
Velocity = 0.000(Ft/s) Flow Rate = 0.000(CFS)
Froude No. = 0.0000
Channel from grade break to crown:
Flow Width = 38.000(Ft.) Flow Area = 16.615(Sq.Ft)
Velocity = 1.976(Ft/s) Flow Rate = 32.836(CFS)
Froude No. = 0.5267
Total flow rate in street = 44.522(CFS)
d. REINFORCED CONCRETE BOXES AND PIPES CAPACITIES
M:\1LAQ010102\ENGR\DESIGN\HYDR\Drainage Study Report.doc
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HYDROLOGY MAP
M:\1LAQ010102\ENGR\DESIGN\HYDR\Drainage Study Report.doc
a. DOWNTOWN DRAINAGE STUDY HYDROLOGY MAP
M:\1LAQ010102\ENGR\DESIGN\HYDR\Drainage Study Report.doc