HomeMy WebLinkAbout20031208.tiff DRAINAGE INVESTIGATION
EROSION CONTROL REPORT
for
SHIRE - P. U. D.
to be located on
Lot C of the Recorded Exemption No. 3092 being a part of the
Northwest Quarter of Section 33, Township 9 North, Range 67 West of
the 6th P. M., Weld County, Colorado
Prepared for:
Lance and Julee Meiners
713 Sitka Street
Fort Collins, Colorado 80524
January 2003
Project No. GRD - 453 - 02
Prepared by:
MESSNER Engineering, Inc.
150 East 29"' Street, Suite 270 Loveland, Colorado 80538-2765 Telephone: (970) 663-2221
2003-1208
E1S�111/LL/J11 V Z1133,
Engineering, Inc.
Project No. GRD - 453 - 02
January 7, 2003
Lance and Julee Meiners
713 Sitka Street
Fort Collins, Colorado 80524
Dear Mr. & Mrs. Meiners:
The enclosed report represents the results of the drainage investigation and erosion control report for
the proposed "Shire - P.U.D." to be located on Lot C of the Recorded Exemption No.3092 in Weld
County, Colorado.
This investigation was based upon: the site development plan; the preliminary construction plans; on
site observations; and available topographic information. The investigation was performed according
to the criteria established by Weld County.
We sincerely appreciate the opportunity to be of service. If you should have any questions or desire
additional information, please feel free to contact this office.
Respectfully submitted,
MESSNER Engineering, Inc.
r<rn-- %Jac
Cameron W. Knapp, Civil Engineer
"I hereby state that this report(plan) for the"Shire- P.U.D.",to be located on Lot C of the Recorded
Exemption No. 3092 in Weld County, Colorado was prepared by me or under my direct supervision for
the owners thereof and meets or exceeds the criteria established by Weld County."
nit
Derti). Messner An
Regi ' tofessi* ngineer
�State SIP �" ' 0109
""��w�171u1xu�a�te6
2- >,-e3
Civil Engineering Consultants
150 E. 29th Street, Suite 270 Loveland, Colorado 80538 (970) 663-2221
TABLE OF CONTENTS
Description Paee
LETTER OF TRANSMITTAL
TABLE OF CONTENTS ii & iii
I GENERAL LOCATION AND DESCRIPTION
A. Location 1
B. Description of Property 1
II EXISTING CONDITIONS
A. Major Basin Description 2
B. Sub Basin Description 3
III DRAINAGE DESIGN CRITERIA
A. Development Regulations 3
B. Development Criteria Reference and Constraints 4
C. Hydrologic Criteria 4
D. Hydraulic Criteria 4
_ IV PROPOSED DRAINAGE DESIGN
A. General Concept 5
V EROSION & WATER QUALITY CONTROL
A. General Concept 7
VI CONCLUSIONS
A. Compliance with Standards 8
VII REFERENCES 9
ii
TABLE OF CONTENTS (CONTINUED):
EXHIBITS
Vicinity Map
Major Drainage Basin Exhibit
_ Existing Conditions Exhibit
Proposed Conditions Exhibit
Flood Insurance Rate Map 080266 0325 C
Grading, Drainage, and Erosion Control Plan
Culvert Plan& Profile & Details
APPENDIX I
Drainage Summary
Drainage Calculations
_ APPENDIX II
Charts, Graphs, Figures and Details
iii
I. General Location and Description:
A. Location
1. The Proposed MEINERS CLUSTER- P.U.D. is located in the Northwest
Quarter of Section 33, Township 9 North, Range 67 West of the 6th P.M. in Weld
County, Colorado.
2. The site is more specifically located on the south side of Weld County Road
100, between Weld County Road 17 and Weld County Road 19. (Refer to the
enclosed vicinity map.)
3. The site is bordered on its north side by Weld County Road 100. Adjoining
the west side of the site are Lots A and B of Recorded Exemption No. 3092. A
_ single family residence situated on each of these lots. To the east lie dry land
farming operations in the unincorporated area of Weld County. Recorded
Exemption Nos. 3148 and 3149 border the property on the south.
B. Description of property
_ 1. The site contains approximately 135 acres and is described as Lot C of the
Recorded Exemption No. 3092. Lot C is a "U" shaped parcel with Lots A and B
of the Recorded Exemption No. 3092 situated in the middle. Approximately 62.5
acres of the western and southern portion of Lot C are to remain undeveloped as a
conservation easement. The proposed development of the site is to take place on
the northeastern 72.41 acres of Lot C. This area is proposed to include six (6)
rural residential estate type lots, a conservation easement and a proposed paved
cul de sac roadway.
a. The rural residential estate lots will range in size from 4 acres to 6.4
acres. Water is be supplied by wells and each lot will have individual
septic disposal systems.
b. A proposed 24-foot wide paved roadway with 4-foot gravel shoulders
will provide access to the six residential lots from Weld County Road 100.
c. Lot 7, which is to be located to the south of the six residential lots, will
comprise approximately 41.5 acres for use as a conservation easement.
2. The site is currently fallow dry land. The existing ground cover consists of
native weeds, grasses and vegetation.
1
3. The site is considered to be gently sloping with existing ground slopes
typically ranging between 1% and 5%. The terrain generally slopes in a northwest
to southeast direction.
4. The "Soil Survey of Weld County Northern Area, Colorado" prepared by the
U.S. Department of Agriculture, Soil Conservation Service, indicated that the
surface soils consist of Ascalon Fine Sandy Loam and Platner Loam.
a. Ascalon Fine Sandy Loam is a well drained soil generally found on
smooth to moderately dissected plains. The "Soil Survey" identifies the
runoff potential as medium, the hazard of water erosion as slight to
moderate, and the hazard of wind erosion as moderate. This soil type is
found mainly on the northern and northeast portions of the site. Ascalon
Fine Sandy Loam is classified in the "B" hydrological group.
b. Platner Loam is also a well drained soil generally found on plains and
adjacent stream terraces. The "Soil Survey" identifies the runoff potential
as slow, the hazard of water erosion as slight, and the hazard of wind
erosion as moderate. This soil type is found mainly on the central and
southern portions of the site. Platner Loam is classified in the "C"
hydrological group.
5. There currently are no irrigation ditches or channels that traverse the site.
II. Existing Conditions
A. Major Basin Description
1. The site lies within a major drainage basin designated Basin 'A' on the Major
Drainage Basin Exhibit (See "Exhibits" section of this report).
a. The basin comprises approximately 645 acres of offsite area that
naturally drains from northwest to southeast across the property. The peak
flow rates for this area are calculated to be approximately 100 c.f.s. during
the 5-year storm and 325 c.f.s. during the 100-year storm.
b. Runoff from the contributing offsite area on the north side of Weld
County Road 100 concentrates approximately 400 feet east of the
intersection of Weld County Roads 100 and 17. At this location, three (3)
36" diameter Corrugated Metal Pipe (CMP) culverts pass flow to the south
side of the road and onto Lot C.
2
c. The natural drainage course continues in a southeast direction,
_ traversing across the site through the proposed conservation easement.
The water surface level within the drainage path during a 100-year storm
does not intrude upon any of the proposed residential lots.
d. Exiting the property and continuing to the southeast, the flow path
eventually merges with the Coal Bank Creek.
2. The site does not lie within a F.E.M.A. designated floodplain or floodway.
(See Flood Insurance Rate Map Community Panel Number 080266 0325 C in the
"Exhibits" section of this report.)
B. Sub Basin Description
1. The existing drainage pattern divides the site into two (2) separate sub-basins
designated Sub-Basins 'A' and `B' as shown on the "Existing Drainage Exhibit."
a. Sub-Basin 'A' contains 6.35 acres of the northern most portion of the
site. This area drains east towards the roadside ditch of Weld County
Road 100. During the 5-year and 100-year storms, the peak runoff rates
for this sub-basin are calculated to be 4.1 c.f.s. and 26.5 c.f.s.
b. The majority of the site, approximately 66.06 acres, is designated Sub-
Basin `B'. This sub-basin drains into the natural drainage path that
traverses through the proposed conservation easement. The peak runoff
rates are 23.4 c.f.s. and 131 c.f.s. for the 5-year and 100-year storm events.
2. All drainage from the site ultimately discharges downstream into the Coal
Bank Creek.
III. Drainage Design Criteria:
A. Development Regulations
1. The requirements of this drainage report are consistent with Section 24-7-110
of the Weld County Code.
2. Since Weld County does not publish technical data or storm drainage design
manuals, certain design criteria comes from the Urban Storm Drainage Criteria
Manual.
r-
3
B. Development Criteria Reference and Constraints
1. The historic drainage pattern on the site will be maintained. The proposed
grading will conform with the existing slope and grades as closely as possible.
Grading will be limited to the proposed roadway and the immediate vicinity of
the proposed homes. The vast majority of the 135 acres that makes up the
development will remain undisturbed.
a. The runoff concentration points, as well as the contributing areas from
the sub-basins, will remain almost identical to the existing conditions.
2. The drainage impact of this site will not adversely affect existing streets,
utilities, or downstream drainage facilities.
C. Hydrological Criteria
1. Table 24.2 of the Weld County Code calls for the initial and major storm
design frequencies of 5 and 100-years.
2. The 5-year and 100-year 24 hour precipitation values were utilized from the
"NOAA Precipitation-Frequency Atlas of the Western U.S., Atlas 2, Volume 3 -
- Colorado".
3. The Soil Conservation Service TR-55 Method was used for calculating the
peak flow rates for the Major Drainage Basin since the contributing offsite area
was greater than 200 acres. For determining the peak runoff rates of the Existing
and Proposed Sub-Basins, the Rational Method was used.
4. Due to the large size of the residential lots, an overall runoff coefficient was
not used for areas considered "residential" as is the case for more urban residential
conditions. Instead, a composite imperviousness for the residential lots was
determined considering each lot to have 3,500 square feet of roof area, 2,500
square feet of pavement area, and 2,000 square feet of graveled area. The
remainder of the lot was considered as "open" area having the same
imperiousness as in the historic conditions.
D. Hydraulic Criteria
I. Culvert design is based upon the hydraulic modeling software by Haestad
Methods called "CULVERT MASTER".
a. The proposed roadway culvert and driveway culverts were designed
using Corrugated Metal Pipe (CMP). CMP is considered to have a
4
Mannings 'n' value of 0.024.
b. The maximum allowable headwater to diameter ratio is 1.5 for the 100-
year storm.
2. The Drainage Swale design is based upon the hydraulic modeling software by
Haestad Methods called"FLOW MASTER".
a. The proposed grassed drainage swale was designed as having a
Mannings n value of 0.30.
3. The contents in the tables, charts, and figures presented in this report, come
_ from the Soil Conservation Service and the Urban Storm Drainage Criteria
Manual. These diagrams facilitated in the drainage design calculations.
a. The worksheets used for the sub-basin drainage calculations, (see
Drainage Calculations in Appendix I of this report), come from the Urban
Storm Drainage Manual. The composite imperiousness of a sub-basin was
_ first computed using the sheets labeled "Area-Weighting for Runoff
Coefficient Calculation". The following sheets labeled "Calculation of a
Peak Runoff Using Rational Method" were used to determine the minor
_ and major peak runoff rates. The time of concentration was determined
using the Peak Runoff Prediction using the Computed Tc instead of the
Regional Tc as shown on the worksheets.
IV. Proposed Drainage Design:
A. General Concept
1. The majority of runoff produced by a large storm event will continue to flow
overland. Runoff from the roadway and most of the residential areas will be
directed within the roadside ditches of the cul de sac. A drainage swale will route
storm water between Lots 3 and 4 to the lot reserved as a conservation easement.
Runoff will exit the site as it has historically done, eventually emptying into the
Coal Bank Creek.
2. The proposed development of the site will result in the creation of four(4)
_ separate sub-basins designated Sub-Basins 'A', `B', 'C', and `D' on the Proposed
Drainage Exhibit.
a. Sub-Basin 'A' makes up 5.32 acres of the northeast portion of the site
that continues to drain eastward toward the roadside ditch of Weld County
5
Road 100. The contributing area includes most of Lot 1 and the east half
of the proposed cul de sac that drains northward. This sub-basin will
produce approximately 4.78 c.f.s during the 5-year storm and 26.6 c.f.s.
during the 100-year storm.
b. Sub-Basin `B' is defined as the area west of the proposed road that
historically drains to the east. This sub-basin makes up 1.03 acres that
drains eastward concentrating at the west side of the intersection of Weld
County Road 100 and the proposed cul de sac. The 5-year and 100-year
peak runoff rates are 1.55 c.f.s. and 5.99 c.f.s. as determined by the
Rational Method. An 18" diameter CMP culvert will be installed at the
roadway crossing to allow flow to continue east within the roadside ditch
of Weld County Road 100.
c. Approximately 10.47 acres makes up Sub-Basin 'C'. This includes the
_ majority of the proposed cul de sac and residential areas. Storm water will
be directed as sheet flow off the roadway and into roadside ditches. The
ditches will merge at the end of the cul de sac and continue south between
Lots 3 and 4 in a drainage swale. The peak runoff rates for this sub-basin
are 8.31 c.f.s. during the 5-year storm and 36.3 c.f.s. during the 100-year
storm. The drainage swale will be located within a drainage easement and
— will have the capacity to carry the 100-year peak flow rate with an
additional one (1) foot of freeboard. The swale will empty into the natural
drain course that traverses through the proposed conservation easement.
d. The remainder of the site, 55.59 acres, is designated Sub-Basin `D'.
This sub-basin encompasses areas from the residential lots as well as Lot
7, the conservation easement. The calculated peak runoff rates during the
minor and major storm events are 22.2 c.f.s. and 123 c.f.s. Drainage from
Sub-Basin 'D' flows overland into the natural drainage course and exits
the site.
3. Driveway culverts will be required for each residential lot. The contributing
area, composite imperviousness, and resulting peak runoff rate to each driveway
culvert was calculated and then the appropriate size of culvert was determined.
a. Since Lots 1 and 6 are located at the high point along the cul de sac, the
minimum culvert size of 15" will be more than adequate.
b. Lots 2 & 3 will each require an 18" diameter culvert and Lots 4 and 5
will require a minimum of 27" diameter culverts.
4. Onsite storm water detention for this site is not necessary.
6
a. Due to the low density and large lot sizes, the overall imperiousness of
the site will not be significantly increased. As determined in the drainage
calculations, (See Drainage Summary, Appendix I), the imperviousness of
the site will increase from 2.35%to 4.45%.
b. The increased storm water runoff due to the development of this site
will be negligible. The increase in the peak runoff rates will be
approximately 5.5 c.f.s. during the 5-year storm and 19.89 c.f.s. during the
100-year storm. The slight increases are due more to a shorter time of
concentration, (more channelized flow routes in the proposed conditions),
than an actual increase in imperviousness of the site.
c. Runoff exiting the site continues in a southwest direction within a
natural drainage and does not pose a threat to adjacent property owners.
Downstream drainage patterns or facilities will not be impacted due to the
slight increase in runoff by the development of the site.
V. Erosion & Water Quality Control:
A. General Concept
1. Erosion control considerations have been made based upon the short term,
during construction activities, and the long term, when development of the
subdivision is complete.
2. The recommended short term erosion control methods to be incorporated into
the construction requirements for the project is the placing of"Silt Fences",
"Straw Bale Inlet Filters", and "Straw Bale Dikes". These are being recommended
in order to prevent debris and sediment from flowing from the areas disturbed by
construction activities onsite to the adjacent streets or properties.
3. The long term measures incorporated to eliminate erosion are the anticipated
methods and materials to be used to provide the ground surface covering at the
driveways and the landscaped areas.
a. The residential structures and surrounding hard-surfaced areas will
provide a deterrent to erosion. The establishment of pasture, lawns and the
combination of landscape plantings and ground covers will aid in deterring
erosion.
b. The grassed lined drainage swale is considered as a Best Management
Practice (BMP) for removal of low levels of suspended solids. The long
7
length, mild slope, and low velocity during the minor storm event will aid
_ is settling sediment before exiting the site.
c. Placement of rip rap at the downstream flared end sections of the
proposed culverts is not necessary since the exiting velocity from the
culverts do not exceed 7.0 feet per second.
4. Wind erosion control measures have not been recommended for the site. It is
anticipated that the disturbed area will be open and subject to wind action for an
extremely short time. If blowing dust is a problem, a combination of surface
roughening and water application is to be used to control the dust.
5. The Owner shall warrant that the measures shown on the approved erosion and
sediment control plan are properly constructed, installed, and are free from
defective material and/or workmanship, for as long as construction on the site
continues, or said measures are necessary to protect against erosion and sediment
transport.
6. Proposed erosion control measures conform to the recommendations of the
Urban Storm Drainage Criteria Manual, and generally accepted erosion control
procedures.
VI. Conclusions:
_ A. Compliance with Standards
1. The proposed development will retain the existing drainage patterns.
2. The site is not located within a designated flood way or flood plain. The
calculated High Water Level produced from the offsite "Major Basin" runoff is
contained within the conservation easement and poses no threat to the proposed
residential or roadway areas.
3. All storm water design criteria is to be performed according to the Weld
County Code or a generally accepted authority approved by the Weld County
Engineer.
4. Temporary measures should be taken to control and prevent mud and debris
_ from being washed or tracked onto the adjacent street and properties. The
completed drainage improvements and landscaping will provide the permanent
erosion and stormwater quality control measures.
5. Due to a slight overall increase of imperviousness of the property, more runoff
will be generated by the proposed development of the property. However, the
8
increase is insignificant and unnoticeable to downstream conditions. Therefore,
storm water detention is not practicable or recommended at this time.
VII. References:
A. Urban Storm Drainage Criteria Manual, Updated 2001.
B. Weld County Code, Chapter 24, Article VII.
C. Soil Survey of Weld County Northern Area, Colorado.
9
EXHIBITS
VICINITY MAP
Scale: 1" =2000'±
s 1 i •_ • I .
_ WCR 100 ,� ` ::•�
'
ITE\ 1'; i I \ ;
I I
_ \E O.92-
••
.. SECS 33 . _N. •,�'•: T
I
- 0r
is WCR 98 ;..�-
r
ii
1 .
i
VICINITY MAP
for
- MEINERS CLUSTER - P. U. D.
To be located on Lot 'C' of Recorded Exemption No. 3092 being a part of the Northwest Quarter
of Section 33, Township 9 North, Range 67 West of the 6th P. M., Weld County, Colorado
II •_ • _ . • ,e-•••• .1/4\4. I -S I - . ‘ ;
•--�J•• ;, • •• Z.J \\ )cl: `-- — _ I �-�- 545 ••\ —• o N
s. •mot `•'�" / • � \•• \ , � ' "\\ •' >1,
c U• \ I C•
o in
•\-,..,.."•., V.....,•:._::.-`` ` •-,•``'- I \` \`, �� • %. 500 2000 •la b a
•
; y •Au '�• ''.l % • _\+ ea. •- _ , ,ti •1 •:• \\ 0 1000 3000 o
- 1' �J.'ye s\+.•• - \• - b\.., t \•r •'\ \w 1" = 1000 _w in
"-- --— __ ,.. , , \ k\\.. i '1
l _ ,- f t•••1•7-..•2' .1` .�\ �, •\ \ + . i '� •\\ rat
1/4
•
-`r `• \ rte• -`,'`\ (3) 3-`••. • % ,• `� t `y, `,.,• _ •.* \, -
' S l _ __-- •.' CuiYert `\\ \ , (2T 40 CM�; 1 I a Cl" R
- _ � \ 1 Culverts `t alma s
\ . k , r 1 W Ulan
\ 1214
ti ; y ` \\f�_ ti_, �, _ \• . Ind cates Extent Of ` r. , c ,_ I 0 W "'E
R. �.. ;'. `' - -� `: % 3ebO' II 100-yr W.S.L. Z
• ;x` —\id
c•� ! t •+ •'-'�• •` !A' • -- i '—r soiz-- _. Typically Indicates Existing
1 ' a \' -: •- `�� : y ' Ground Surface Contour
isi -J
1 I
-1. • !'e :••, t. 644.5 acs. `+•• _ �'
I-
i. % �'' • �� Drainage Basin Limit Identifier., '' : T` `. ` + ` • \ `\\ 4 __rDATE: JAN. 9. 2003
4
r \J . 'J ?
I _ : I. �, " -_` J. \ _ -- Typically Indicates Drainage
\ `•. �\v t ` vj'� • .1 •.. •\ — ar.Y •yar.a—.,a.��e_ Flow Direction
4.. ,� ' -ie.,. • 1.1 • 1'. •+\``j • - I - ••' •~' . ` .' "1 SCALE: AS NOTED
\ r `� �_ '\ , •
\ ' \ \ _�`' �� Concentration Point Identifier DRAWN: C.W.K.
`\\ \ �� � � �: i 1 ,�•.,• ;': ;t; a # Design Point, Basin Number CHKD: D.R.M
\ ` \ i ._1I . • ' I ♦ 4 Basin 'B'—�
\ \, •G 5 ( • j ; ' j"'~ '.� ' \1�1 t ,� :• Project No.
\ • i • i .-11 t E
�� Acres
`� . 3.4 6J 0 100 c.f.s.
'A' / -
6.35 ac. ) ) ( i I / / // /7/// / ��' /�
4. 1426.5 % 543 /
o /
�� 543 l// / ((/ ( 7
� p /44Y/V _
7 h / 666ac. c to
1 / 1,4-
�O h ' ash/° h N 3.4 131 �/ //,
h°� i c
�O j , 3 s! K \. a Is.* /AY,
/ /` / / ofC 0 / ' � o
7 �._.�. 5447 \ i b' \
, 7
erl\ \ 1 \ hp 7b.
`L E
!)-
<
../ / / ) ti ( (
I k ( c ___T .21.-r-- - tr)445 \ i / / `� �� ,y / o N
)r^.. d,/ V1 c
w
� N
v/j Z � 5446 / i ( I N / ao j / ' �^�� Fli
% ` U W,( I 74L I ) 1. o i a rn
O � ( K Sg \ / 0 o K \
o o v
(3//7co/ ,, /\ ( tni/7\) ) to 7 /\"\\ ;2 / i X / 1 4(31'
_I ( I KiTro) N:
vS 54¢0 \\ J� �, n / / /NI In� �� 54¢¢ S¢¢� �, vii \V t �i4 a' 1s ' \ $450 54\4¢\2 �\ Q oV op i
s ' / 5 / ^ o FDA
W
\ \\' zap
1 / i
I (\\ 5422 `\\: CFI" I 0
5453--..\\ l /` a 542�� Z ill
5—_ - - y LT-
--0— W o 1 \\\\\60 0 5423 - _.._RON ) i I iii i //////4 /1/4 // 5427PO
546 $� -2-95435043-
o I a x w
p 542 5429 \,_1_
w w r4
I� J ill ® /..______/H ��5430 I/ Wl U
Typically Indicates Existing 5431 J
1 1 i
Sot2 Yo Y 9 �,� / \ , �� z
Ground Surface ::entifier
—� 5432 � `6 \ l�� Drainage Basin � �� \\\
o I u
o N _
--.(7.-, TTYPicolly Indicates Drainage DATE: JAN. 9. 2003
--.(7.-,
Flow Direction SCALE: AS NOTED
Concentration Point Identifier 50 200 DRAWN: M.L D
wilmow
Y4 Basin 'B'^— Design Point, Basin Number o 100 300
CMKD: D.R.M
t" = 200' Project No.
5.23 ac. Area of basin in Acres GRD-453-02
3.4 6.7
QZ c.f.s.Q+00 c.f.s.
SHEET
2 of 3
/
i I __.-_, 5.32 ac. ) / / ( l / / / / i i / 1 { L9V4 /// 1 Y/// // / to
01
"'
7.8636. 5A�5 l // /i / / i / c
- / /// / o) � l / ! - /1// PO i-
1 iN
I I I /5.59 ac. � ,//// v tO
m
I / / / / // /J I o°Lii. i_CT - .'" / 72.21 /// //
177/1/ v\z/// Ii
E
I /// / / /<0.47 \ /// / // V 1 c
l <(/// V L
/� ', /� .3136. / J/// /
y\ :
( ( (74
///
/ � �i
/0 �!, 1 .03 oc. \ /tic
I I
/ h
7J v1 .555.99 \.-_,.\\N ‘5;: \ � \ ' ( ( ltri i 7( 7 I CI)
v�
:/3I II/ \ �T � s'4s Div 0I /411/
4 °�\ \ 7 , , /i �� in i
%.„\\\ \\)'\
I1 t--- v 1\ \ ‘ \ \ 7' 1 z
5450—\ \� '`{�\\ /(k/ / HEW w ci a A/ I i , \\,,, ,5,4„,f__ ____ _ , (X60 //ft. o \\\\ \ \ 1 c) \\ I
K \ /1/ \--------\_ _ __ _, Typically Indicates Existing 4e7/4.7.--:::/� 5430 \ . .
Ground Surface Contour % /� -\
I
--k 1 / z
1 I <
—solz— Typically Indicates Proposed // / ill � o wFinish Surface Contour 7 I ///7------
/ o ,--
�� �' Drainage Basin Limit Identifier /��� i V \ V� N / / ) � \ \ \ o E
o N_c_, T�pically Indicates Drainage DATE: JAN, 9. 20Q3
i-IOW Direction SCALE: AS NQTFD
0' Concentration Point Identifier 50 200 DRAWN: M LD.
mom........ommummom cHKD: D.R M
114 Basin 'B'----- Design Point, Basin Number o 100 300
Area of basin in Acres 1" = 200' Project No.
5.23 ac. GRD-453-02
Qlw c.f.s.
3.4 6.7 SHEET
Q10 c.f.s. 3 of 3
Drainage Investigation and
Erosion Control Report
contains the following
oversized maps :
Grading, Drainage and Erosion Control Plan
Culvert Plan and Profile and Details Sheet
See Original File
I I I I I I I I I I I I I I I I I I I
) ) )
It 2 4 ,f{.., 1'�1
}�t \ 22 1 23
\ 41♦a
(J -�„..e., AIP*OXIMATE SCALE
f t t j:21. 20.0
' N_. - I \--. \ N \\_ ,\ 29 I\ j
I \2B •Y 21 26
\ \ \ \ I I I:NSINII IOSIIISu uElmo.
J I
,\, \ FIRM
-1+;:t.*' FLOOD NSORARC[RAT[MAP
,10
_ — \ i f WELD
II \ \..11 'COUNTY,
I COLORADO
'�— i..; vemEcoaPour®w3un
--- --II ,t. � iPAMR 325 OF 1015
Imo— 34 35 —� .,»•............. .
at a3
1 `'
/ —_ __� - •T IA" n CRMMIIPIT4IARAA MIMNI
71 'ta
010266 031!C\ ; I__�__ __�__—_--�J L.——___ �r \-- ��J �, �� SEPTEMMAP BER 28 1981
9 3
2 —N \ ,.1.,
Jill \ �� This ..aa.c.o:MR -.TM. .� map I
APPENDIX I
_ DRAINAGE SUMMARY
DRAINAGE CALCULATIONS
DRAINAGE SUMMARY
Area-Weighting for Runoff Coefficient Calculation •
Project Title: Meiners Cluster P.U.D.
Catchment ID: EXISTING CONDITIONS
Illustration
6c_ee.t
LEGEND:
Flow Direction
eB 4
5 Catchment
Submit*3 Bormdaiy
Instructions: For each catchment subarea,enter values for A and C.
Subarea Area Runoff Product
ID acres Coeff.
A C* CA
input input input output
— Pavement 0.26 100.00 26.00
Open 72.15 2.00 144.30
Sum: 72.41 Sum: 170.30
Area-Weighted Runoff Coefficient(sum CA/sum A)= 2.35
*See sheet"Design Info"for inperviousness-based runoff coefficient values.
Messner Engineering,Inc.
— CALCULATION OF A PEAK RUNOFF USING RATIONAL METHOD
Project Title: Meiners Cluster P.U.D.
Catchment ID: EXISTING CONDITIONS 5-yr.Peak Runoff Rate
I. Catchment Hydrologic Data
— Catchment ID= EXISTING
Area= 7241 Acres
Percent Imperviousness= 2.35 %
NRCS Soil Type= C A, B,C,or D
II. Rainfall Information I(inch/hr)=Cl*P1 /(C2+Td)^C3
— Design Storm Return Period,Tr= 5 years (input return period for design storm)
C1 = 28.50 (input the value of C1)
C2= 10.00 (input the value of C2)
C3= 0.786 (input the value of C3)
— P1= 2.50 inches (input one-hr precipitation—see Sheet"Design Info")
III. Analysis of Flow Time(lime of Concentration)for a Catchment
— Runoff Coefficient, C= 0.17
Overide Runoff Coefficient, C= (enter an overide C value if desired,or leave blank to accept calculated C.)
5-yr. Runoff Coefficient, C-5= 0.17
— Overide 5-yr. Runoff Coefficient, C= (enter an overide C-5 value if desired, or leave blank to accept calculated C-5.)
Illustration
nerland LEGEND
Reach 1 flew
Reach 2• O Beginning
— Flew Direction
4---
Catrhnent
Reach 3 Bousulacy
—
NRCS Land Heavy Tillage/ Short Nearly Grassed Paved Areas&
Type Meadow Field Pasture/ Bare Swales/ Shallow Paved Swales
Lawns Ground Waterways (Sheet Flow)
—
Conveyance 2.5 5 7 10 15 20
Calculations: Reach Slope Length 5-yr NRCS Flow Flow
_ ID S L Runoff Convey- Velocity Time
Coeff ance V Tf
NR ft C-5 fps minutes
input input output input output output
— Overland 0.0240 500 0.17 0.29 28.26
1 0.0170 1,589 5.00 0.65 40.62
2 0.0042 357 15.00 0.97 6.12
3
— 4
5
Sum 2,446 Computed Tc= 75.01
Regional Tc= 23.59
— N.
Peak Runoff Prediction using Computed Tc action using Regional Tc
— Rainfall Intensity at Tc, I= 2.17 inch/hr Rainfall Intensity at Tc, I= 4.50 inch/hr
Peak Flowrate, Qp= 25.98 cfs Peak Flowrate, Qp= 53.90 cfs
—
Messner Engineering,Inc.
•
CALCULATION OF A PEAK RUNOFF USING RATIONAL METHOD
r.. Project Tide: Meiners Cluster P.U.D.
Catchment ID: EXISTING CONDITIONS 100-yr.Peak Runoff Rate
I. Catchment Hydrologic Data
Catchment ID= EXISTING
Area= 72.41 Acres
Percent Imperviousness= 2.35 %
NRCS Soil Type= C A, B,C,or D
II. Rainfall Information I(inchlhr)=Cl •P1 l(C2+Td)"C3
Design Storm Return Period,Tr= 100 years (input return period for design storm)
C1 = 28.50 (input the value of C1)
C2= 10.00 (input the value of C2)
C3= 0.786 (input the value of C3)
P1= 4.50 inches (input one-hr precipitation—see Sheet"Design Info")
III. Analysis of Flow Time(Time of Concentration)for a Catchment
Runoff Coefficient, C= 0.51
Overide Runoff Coefficient,C= (enter an overide C value if desired,or leave blank to accept calculated C.)
5-yr. Runoff Coefficient, C-5= 0.17
Overide 5-yr. Runoff Coefficient, C = (enter an overide C-5 value if desired, or leave blank to accept calculated C-5.)
Illustration
�-
-------•
LEG]]VD
Reach 1 flee
Reach 2. O Beginning
Flow Dlrecibn
Catehment
Reack 3 Beunaaay
NRCS Land Heavy Tillage/ Short Nearly Grassed Paved Areas&
Type Meadow Field Pasture/ Bare Swales/ Shallow Paved Swales
Lawns Ground Waterways (Sheet Flow)
Conveyance 2.5 I 5 I 7 10 15 20
Calculations: Reach Slope Length 5-yr NRCS Flow Flow
ID S L Runoff Convey- Velocity Time
Coeff ance V Tr
NR R C-5 fps minutes
input input output input output output
_ Overland 0.0240 500 0.17 0.29 28.26
1 0.0170 1,589 5.00 0.65 40.62
2 0.0042 357 15.00 0.97 6.12
3
_ 4
5
Sum 2,446 Computed Tc= 75.01
Regional Tc= 23.59
— Iv.
Peak Runoff Prediction using Computed Tc lotion using Regional Tc
Rainfall Intensity at Tc, I= 3.90 inch/hr Rainfall Intensity at Tc, I= 8.10 inch/hr
Peak Flowrate, Qp= 143.77 efs Peak Flowrate,Op= 298.29 ofs
Messner Engineering,Inc.
Area-Weighting for Runoff Coefficient Calculation
Project Title: Meiners Cluster P.U.D.
Catchment ID: PROPOSED CONDITIONS
Illustration
ses1
LEGEND:
Flow Direction
twos 1
S Catchm eat
Sidman 3 Boundary
Instructions: For each catchment subarea,enter values for A and C.
Subarea Area Runoff Product
ID acres Coeff.
A C* CA
input input input output
— Pavement 1.19 100.00 119.00
Open 70.26 2.00 140.52
Gravel 0.48 40.00 19.20
Roof 0.48 90.00 43.20
sum: 72.41 sum: 321.92
Area-Weighted Runoff Coefficient(sum CA/sum A)= 4.45
*See sheet"Design Info"for inperviousness-based runoff coefficient values.
— Messner Engineering,Inc.
_ CALCULATION OF A PEAK RUNOFF USING RATIONAL METHOD
Project Title: Meiners Cluster P.U.D.
Catchment ID: POROPOSEDCONDITIONS 5-yr.Peak Runoff Rate
—
I. Catchment Hydrologic Data
Catchment ID= PROPOSED
—
Area= 72.41 Acres
Percent Imperviousness= 4.45 %
NRCS Soil Type= C A, B,C,or D
11. Rainfall information I(Inch/hr)=C1 *P1/(C2+Td)•C3
— Design Storm Return Period,Tr= 5 years (input return period for design storm)
C1 = 28.50 (input the value of C1)
C2= 10.00 (input the value of C2)
C3= 0.786 (input the value of C3)
— P1= 2.50 inches (input one-hr precipitation—see Sheet"Design Info")
III. Analysis of Flow Time(Time of Concentration)for a Catchment
— Runoff Coefficient, C= 0.18
Overide Runoff Coefficient, C = (enter an overide C value if desired,or leave blank to accept calculated C.)
5-yr. Runoff Coefficient, C-5= 0.18
Overide 5-yr. Runoff Coefficient, C= (enter an overide C-5 value if desired,or leave blank to accept calculated C-5.)
Illustration
°verlaal LEGEND
Reach 1 flew
Reuh2• 0 Beg3roting
— Flow Direction
Catchment
Reach 3 Bratty
NRCS Land Heavy Tillage/ Short Needy Grassed Paved Areas&
Type Meadow Field Pasture/ Bare Swales/ Shallow Paved Swales
Lawns Ground Waterways (Sheet Flow)
—
Conveyance 2.5 5 7 10 15 20
Calculations: Reach Slope Length 5-yr NRCS Flow Flow
ID S L Runoff Convey- Velocity Time
—
Coeff ance V Tf
ft/ft ft C-5 fps minutes
input input output input output output
Overland 0.0300 500 0.18 0.32 25.89
-
1 0.0180 1,082 5.00 0.67 26.88
2 0.0041 610 15.00 0.96 10.59
3
_ 4
5
Sum 2,192 Computed Tc= 63.36
Regional Tc= 22.18
_ IV.
Peak Runoff Prediction using Computed Tc edictlon using Regional Tc
Rainfall Intensity at Tc, I= 2.44 inch/hr Rainfall Intensity at Tc, I= 4.65 inch/hr
Peak Flowrate, Op= 31.48 cfs Peak Flowrate,Op= 60.16 cfs
—
Messner Engineering,Inc.
— CALCULATION OF A PEAK RUNOFF USING RATIONAL METHOD
Project Title: Meiners Cluster P.U.D.
Catchment ID: POROPOSED CONDITIONS 100-yr.Peak Runoff Rate
I. Catchment Hydrologic Data
— Catchment ID= PROPOSED
Area= 72.41 Acres
Percent Imperviousness= 4.45 %
NRCS Soil Type= C A, B, C,or D
II. Rainfall Information I(inchltrr)=C1 *P1 /(C2+Td)"C3
— Design Storm Return Period,Tr= 100 years (input return period for design storm)
C1 = 28.50 (input the value of C1)
C2= 10.00 (input the value of C2)
C3= 0.786 (input the value of C3)
-- P1= 4.50 inches (input one-hr precipitation—see Sheet"Design Info")
III. Analysis of Flow Time(Time of Concentration)for a Catchment
Runoff Coefficient,C= 0.52
Overide Runoff Coefficient,C= (enter an overide C value if desired,or leave blank to accept calculated C.)
5-yr. Runoff Coefficient, C-5= 0.18
— Overide 5-yr. Runoff Coefficient, C= (enter an overide C-5 value if desired,or leave blank to accept calculated C-5.)
Illustration
^ •--------
�
overland LEGII`ID
Reach l flaw
Reach 2• O Begimruig
— flow Direction
Catchment
Reach 3 Bury
—
NRCS Land Heavy Tillage/ Short Nearly Grassed Paved Areas 8
Type Meadow Field Pasture/ Bare Swales/ Shallow Paved Swales
Lawns Ground Waterways (Sheet Flow)
—
Conveyance 2.5 5 7 10 15 20
Calculations: Reach Slope Length 5-yr NRCS Flow Flow
ID S L Runoff Convey- Velocity Time
Coeff ance V Tf
ftM ft C-5 fps minutes
input input output input output output
— Overland 0.0300 500 0.18 0.32 25.89
1 0.0180 1,082 5.00 0.67 26.88
2 0.0041 610 15.00 0.96 10.59
3
— 4
5
Sum 2,192 Computed To= 63.36
Regional Tc= 22.18
_ N.
Peak Runoff Prediction using Computed Tc jedlotion using Regional Tc
_
Rainfall Intensity at Tc, I= 4.38 inch/hr Rainfall Intensity at Tc, I= 8.38 inch/hr
Peak Flowrate, Qp= 163.66 cfs Peak Flowrate, Qp= 312.78 cfs
_
—
Messner Engineering,Inc.
_ DRAINAGE CALCULATIONS
Client: Lance &Julee Meiners Project No. GRD-453-02
Project: Meiners Cluster P.U.D. Date: Jan. 10, 2003
Location: Section 33, T 9 N, R 67 W, Weld County, Colorado By: C.W.K
Determine Storm Water Peak Run-off Rates Using the U.S.D.A. Soil Conservation Service
Method "TR-55."
EXISTING CONDITIONS:
Consider Onsite Area that combines with Offsite Areas to drain from the West into the Handy Ditch at the
ites southern boundary.
Site Area "A"= 644.5 acres= 1 sq. mi.
Overland Surface Condition: Pasture
Overland flow path = 9470 Ft.
Overland Slope = 1
Flow Velocity from SCS Nomograph = 0.75 Ft. /Sec.
Overland Time of Concentration, T"= 210.44 Min.
Soil Group Classification = B & C
CN = 74
Ps= 2.5 Inches Pico= 4.5 Inches
Q = (P-0.2S)2+(P + 0.8S)
S= 1000/CN- 10 = 3.51
Qs= (2.50- 0.2(3.51))2+ (2.50 + 0.8(3.51)) = 0.61 Inches
Qioo= (4.5- 0.2(3.51))2+ (4.5 + 0.8(3.51)) = 1.97 Inches
Total Time of Concentration,Tc= To +Tch= 210.44 Min.
Tc= 3.51 Hour
Peak Discharge, qp, from Fig. 4.4.4 - 1 Tc= 3.51 Hr. = 165 csm /inch
Area "A"-qs= gpxAQ = 165x1.0x0.61 = 100.36 c.f.s.
Area"A"-gioo= qp x AQ = 165 x 1.0 x 1.97 = 325.44 c.f.s.
Page 1
Area-Weighting for Runoff Coefficient Calculation
Project Title: Meiners Cluster P.U.D.
Catchment ID: EXISTING SUB-BASIN'A'
Illustration
se't
LEGEND:
Flow Direction
... 5°U°te CareLm enr
Subarea 3 Boundary
Instructions: For each catchment subarea,enter values for A and C.
Subarea Area Runoff Product
ID acres Coeff.
A C" CA
input input input output
— ^ Pavement 0.26 100.00 26.00
Undev. 6.09 2.00 12.18
Sum: 6.35 sum: 38.18
Area-Weighted Runoff Coefficient(sum CAlsum A)= 6.01
*See sheet"Design Info"for inperviousness-based runoff coefficient values.
Messner Engineering,Inc. Page 2
CALCULATION OF A PEAK RUNOFF USING RATIONAL METHOD
Project Title: Meiners Cluster P.U.D.
Catchment ID: EXISTING SUB-BASIN'A' 5-yr. Peak Runoff Rate
I. Catchment Hydrologic Data
Catchment ID= A'
Area= 6.35 Acres
Percent Imperviousness= 6.01 %
NRCS Soil Type= B A, B, C,or D
II. Rainfall Information I(inch/hr)=C1 *P1 /(C2+Td)^C3
Design Storm Return Period,Tr= 5 years (input return period for design storm)
C1 = 28.50 (input the value of C1)
C2= 10.00 (input the value of C2)
C3= 0.786 (input the value of C3)
P1= 2.50 inches (input one-hr precipitation—see Sheet"Design Info")
III. Analysis of Flow Time(Time of Concentration)for a Catchment
Runoff Coefficient, C= 0.11
Overide Runoff Coefficient, C= (enter an overide C value if desired,or leave blank to accept calculated C.)
5-yr. Runoff Coefficient, C-5= 0.11
—
Overide 5-yr. Runoff Coefficient, C= (enter an overide C-5 value if desired,or leave blank to accept calculated C-5.)
Illustration
---
•
*liana LEGEND
Reach 1 Raw
— Reach 2• O Beghadeg
now Direction
4E—
Catchment
— Reach 3 B.euula9'
NRCS Land Heavy Tillage/ Short Nearly Grassed Paved Areas&
Type Meadow Field Pasture/ Bare Swales/ Shallow.Paved Swales
— Lawns Ground Waterways (Sheet Flow)
Conveyance 2.5 5 7 10 15 20
Calculations: Reach Slope Length 5-yr NRCS Flow Flow
—
ID S L Runoff Convey- Velocity Time
Coeff ance V Tf
ft/ft ft C-5 fps minutes
input input output input output output
—
Overland 0.0380 26 0.11 0.07 5.88
1 0.0220 975 15.00 2.22 7.30
2
3
-
5
Sum 1,001 Computed Tc= 13.18
Regional Tc= 15.56
IV.
Peak Runoff Prediction using Computed Tc ictlon using Regional Tc
Rainfall Intensity at Tc, I= 6.02 inch/hr Rainfall Intensity at Tc, I= 5.58 inch/hr
— Peak Flowrate, Op= 4.14 cfs Peak Flowrate, Clp= 3.83 cfs
—
Messner Engineering,Inc. Page 3
•
CALCULATION OF A PEAK RUNOFF USING RATIONAL METHOD
•
_ Project Title: Meiners Cluster P.U.D.
Catchment ID: EXISTING SUB-BASIN'A' 100-yr. Peak Runoff Rate
I. Catchment Hydrologic Data
Catchment ID= A'
Area= 6.35 Acres
Percent Imperviousness= 6.01 %
NRCS Soil Type= B A, B, C,or D
II. Rainfall Information I(inch/hr)=C1 *P1 l(C2+Td)^C3
Design Storm Return Period,Tr= 100 years (input return period for design storm)
C1 = 28.50 (input the value of C1)
C2= 10.00 (input the value of C2)
C3= 0.786 (input the value of C3)
P1= 4.50 inches (input one-hr precipitation—see Sheet"Design Info")
M. Analysis of Flow Time(Time of Concentration)for a Catchment
Runoff Coefficient, C= 0.38
Overide Runoff Coefficient,C= (enter an overide C value if desired,or leave blank to accept calculated C.)
5-yr. Runoff Coefficient, C-5= 0.11
Overide 5-yr. Runoff Coefficient, C= (enter an overide C-5 value if desired,or leave blank to accept calculated C-5.)
Illustration
_ ..
.tlead LEGEND
Reach 1 fttw
Reach 2• O B
aginidaS
Flea Dtrecihn
�
Catchm.nt
Reach 3 Soudan.
NRCS Land Heavy Tillage/ Shat Nearty Grassed Paved Areas 8
Type Meadow Field Pasture/ Bare Swales/ Shallow Paved Swales
Lawns Ground Waterways (Sheet Flow)
Conveyance 2.5 5 7 [ 10 1 15 20
_ Calculations: Reach Slope Length 5-yr NRCS Flow Flow
ID S L Runoff Convey- Velocity Time
Coeff ance V IT
ft/ft ft C-5 fps minutes
input input output input output output
Overland 0.0380 26 0.11 0.07 5.88
1 0.0220 975 15.00 2.22 7.30
2
3
4
5
Sum 1,001 Computed Tc= 13.18
_ Regional Tc= 15.56
IV.
— Peak Runoff Prediction using Computed Tc jedictlon using Regional Tc
Rainfall Intensity at Tc, I = 10.84 inch/hr Rainfall Intensity at Tc, I= 10.04 inch/hr
Peak Flowrate, Op= 26.46 cfs Peak Flowrate, Op= 24.50 cfs
Messner Engineering,Inc. Page 4
CALCULATION OF A PEAK RUNOFF USING RATIONAL METHOD
•
_ Project Title: Meiners Cluster P.U.D.
Catchment ID: EXISTING SUB-BASIN 5-yr. Peak Runoff Rate
I. Catchment Hydrologic Data
Catchment ID= B'
Area= 66.06 Acres
Percent Imperviousness= 2.00 %
NRCS Soil Type= C A, B,C,or D
II. Rainfall Information I(inchlhr)=C1 *P1 l(C2+Td)AC3
Design Storm Return Period, Tr= 5 years (input return period for design storm)
C1 = 28.50 (input the value of C1)
C2= 10.00 (input the value of C2)
C3= 0.786 (input the value of C3)
P1= 2.50 inches (input one-hr precipitation—see Sheet"Design Info")
III. Analysis of Flow Time(Time of Concentration)for a Catchment
Runoff Coefficient,C= 0.16
Overide Runoff Coefficient, C= (enter an overide C value if desired,or leave blank to accept calculated C.)
_ 5-yr. Runoff Coefficient, C-5= 0.16
Overide 5-yr. Runoff Coefficient, C= (enter an overide C-5 value if desired,or leave blank to accept calculated C-5.)
Illustration
.verb" LEGEND
Reach 1 flaw
Reach 2• O Beginning
now Direction
Cathm.nt
Reach 3 BounLr
NRCS Land Heavy Tillage/ Short Nearly Grassed Paved Areas 8
Type Meadow Field Pasture/ Bare Swales/ Shallow Paved Swales
Lawns Ground Waterways (Sheet Flow)
Conveyance 2.5 5 7 10 15 20
_ Calculations: Reach Slope Length 5-yr NRCS Flow Flow
ID S L Runoff Convey- Velocity Time
Coeff ance V If
ft/ft ft C-5 fps minutes
input input output input output output
Overland 0.0240 500 0.16 0.29 28.33
1 0.0170 1,589 5.00 0.65 40.62
2 0.0042 357 15.00 0.97 6.12
3
4
5
Sum 2,446 Computed Tc= 75.08
_ Regional Tc= 23.59
IV.
— _ Peak Runoff Prediction using Computed Tc ictlon using Regional Tc
Rainfall Intensity at Tc, I= 2.17 inch/hr Rainfall Intensity at Tc, I= 4.50 inch/hr
Peak Flowrate, Op= 23.36 cfs Peak Flowrate,Op= 48.50 cfs
Messner Engineering,Inc. Page 5
CALCULATION OF A PEAK RUNOFF USING RATIONAL METHOD.-
--
Project Title: Meiners Cluster P.U.D.—
UUUU
Catchment ID: EXISTING SUB-BASIN'B' 100-yr.Peak Runoff Rate
I. Catchment Hydrologic Data
Catchment ID= B'
Area= 66.06 Acres
Percent Imperviousness= 2.00 %
— NRCS Soil Type= C A, B, C,or D
II. Rainfall Information I(inch/lir)=C1 *P1 /(C2+Td)*C3
Design Storm Return Period,Tr= 100 years (input return period for design storm)
C1 = 28.50 (input the value of C1)
C2= 10.00 (input the value of C2)
— C3= 0.786 (input the value of C3)
P1= 4.50 inches (input one-hr precipitation—see Sheet"Design Info")
M. Analysis of Flow Time(Time of Concentration)for a Catchment
Runoff Coefficient, C= 0.51
Overide Runoff Coefficient, C= (enter an overide C value I desired,or leave blank to accept calculated C.)
5-yr. Runoff Coefficient, C-5= 0.16
—
Overide 5-yr. Runoff Coefficient, C= (enter an overide C-5 value if desired,or leave blank to accept calculated C-5.)
Illustration
overland LEGEND
Reach 1 flay
— Reach 2. O Bing
now Diraihn
F—
Cathaaant
Reach) Beendaey
NRCS Land Heavy Tillage/ Short Nearly Grassed Paved Areas&
Type Meadow Field Pasture/ Bare Swales/ Shallow Paved Swales
— Lawns Ground Waterways (Sheet Flow)
Conveyance 2.5 5 7 10 15 20
Calculations: Reach Slope Length 5-yr NRCS Flow Flow
_
ID S L Runoff Convey- Velocity Time
Coeff ance V Tf
ft/ft ft C-5 fps minutes
— input input output input output output
Overland 0.0240 500 0.16 0.29 28.33
1 0.0170 1,589 5.00 0.65 40.62
2 0.0042 357 15.00 0.97 6.12
3
4
5
Sum 2,446 Computed Tc= 75.08
— Regional Tc= 23.59
IV.
Peak Runoff Prediction using Computed Tc iction using Regional Tc
Rainfall Intensity at Tc, I= 3.90 inch/hr Rainfall Intensity at Tc, I= 8.10 inch/hr
— Peak Flowrate, Qp= 130.77 cfs Peak Flowrate,Qp= 271.48 cfs
—
Messner Engineering,Inc. Page 6
Area-Weighting for Runoff Coefficient Calculation
Project Title: Meiners Cluster P.U.D.
Catchment ID: PROPOSED SUB-BASIN'A'
Illustration
si
st_e
LEGEND:
Flow Direction
u
se Catchment
Subarea 3 gay
Instructions: For each catchment subarea,enter values for A and C.
_ Subarea Area Runoff Product
ID acres Coeff.
A C" CA
input input input output
Pavement 0.27 100.00 27.00
Open 4.89 2.00 9.78
Gravel 0.08 40.00 3.20
Roof 0.08 90.00 7.20
— sum: 5.32 Sum: 47.18
Area-Weighted Runoff Coefficient(sum CA/sum A)= 8.87
*See sheet"Design Info"for inperviousness-based runoff coefficient values.
Messner Engineering,Inc. Page 7
CALCULATION OF A PEAK RUNOFF USING RATIONAL METHOD
Project Title: Meiners Cluster P.U.D.
—
Catchment ID: PROPOSED SUB-BASIN'A' 5-yr. Peak Runoff Rate
I. Catchment Hydrologic Data
Catchment ID= A'
Area= 5.32 Acres
Percent Imperviousness= 8.87 %
_ NRCS Soil Type= B A, B, C,or D
II. Rainfall Information I(inch/hr)=C1 *P1 /(C2+Td)=C3
Design Storm Return Period,Tr= 5 years (input return period for design storm)
C1 = 28.50 (input the value of C1)
C2= 10.00 (input the value of C2)
— C3= 0.786 (input the value of C3)
P1= 2.50 inches (input one-hr precipitation—see Sheet"Design Info")
III. Analysis of Flow Time(Time of Concentration)for a Catchment
Runoff Coefficient, C= 0.13
Overide Runoff Coefficient, C= (enter an overide C value if desired, or leave blank to accept calculated C.)
5-yr. Runoff Coefficient, C-5= 0.13
—
Overide 5-yr. Runoff Coefficient, C = (enter an overide C-5 value if desired,or leave blank to accept calculated C-5.)
Illustration
°valad LEG
Reach 1 flaw
— Reach 2, O Ramming
Flow Direction
4 —
Catthnrnt
Reach 3 Boundary
NRCS Land Heavy Tillage/ Short Nearly Grassed Paved Areas&
Type Meadow Field Pasture/ Bare Swales/ Shallow Paved Swales
Lawns Ground Waterways (Sheet Flow)
Conveyance 2.5 5 7 10 15 20
Calculations: Reach Slope Length 5-yr NRCS Flow Flow
—
ID S L Runoff Convey- Velocity Time
Coeff ance V Tf
ft/ft ft CS fps minutes
input input output input output output
—
Overland 0.1100 23 0.13 0.10 3.81
1 0.0188 665 15.00 2.06 5.39
2
3
—
5
Sum 688 Computed Tc= 9.20
_ Regional Tc= 13.82
IV.
Peak Runoff Prediction using Computed Tc lotion using Regional Tc
Rainfall Intensity at Tc, I= 6.98 inch/hr Rainfall Intensity at Tc, I= 5.89 inch/hr
— Peak Flowrate,Op= 4.78 cfs Peak Flowrate,Op= 4.04 cfs
—
Messner Engineering,Inc. Page 8
CALCULATION OF A PEAK RUNOFF USING RATIONAL METHOD
_ Project Title: Meiners Cluster P.U.D.
Catchment ID: PROPOSED SUB-BASIN'A' 100-yr.Peak Runoff Rate
I. Catchment Hydrologic Data
Catchment ID= N
Area= 5.32 Acres
Percent Imperviousness= 8.87 %
NRCS Soil Type= B A, B, C,or D
II. Rainfall Information I(Inch/hr)=Cl •P1 /(C2+Td)*C3
Design Storm Return Period,Tr= 100 years (input return period for design storm)
C1 = 28.50 (input the value of C1)
C2= 10.00 (input the value of C2)
C3= 0.786 (input the value of C3)
P1= 4.50 inches (input one-hr precipitation—see Sheet"Design Info")
ill. Analysis of Flow Time(lime of Concentration)for a Catchment
Runoff Coefficient, C= 0.40
Overide Runoff Coefficient, C= (enter an overide C value f desired,or leave blank to accept calculated C.)
5-yr. Runoff Coefficient, C-5= 0.13
Overide 5-yr. Runoff Coefficient, C= (enter an overide C-5 value if desired, or leave blank to accept calculated C-5.)
Illustration
�-
----—-
�
everla"d LEGEND
Reach 1 flew
Reach 2• O Beginning
Flow Direction
Cat iunent
Reach 3 Boundary
NRCS Land Heavy Tillage/ Short Nearly Grassed Paved Areas 8
Type Meadow Field Pasture/ Bare Swales/ Shallow Paved Swales
Lawns Ground Waterways (Sheet Flow)
Conveyance 2.5 5 7 10 15 20
Calculations: Reach Slope Length 5-yr NRCS Flow Flow
ID S L Runoff Convey- Velocity Time
Coeff ance V Tt
ftM ft C-5 fps minutes
input input output input output output
Overland 0.1100 23 0.13 0.10 3.81
1 0.0188 665 15.00 2.06 5.39
2
3
4
5
Sum 688 Computed Tc= 9.20
Regional Tc= 13.82
IV.
Peak Runoff Prediction using Computed Tc iction using Regional Tc
Rainfall Intensity at Tc, I= 12.57 inch/hr Rainfall Intensity at Tc, I= 10.61 inch/hr
Peak Flowrate, Op= 26.64 cfs Peak Flowrate, Op= 2248 cfs
Messner Engineering,Inc. Page 9
Area-Weighting for Runoff Coefficient Calculation •
Project Title: Meiners Cluster P.U.D.
Catchment ID: PROPOSED SUB-BASIN 'B'
Illustration
S '`e'�
LEGEND:
Flow Direction
See Catchment
Subarea 3 Boundary
Instructions: For each catchment subarea,enter values for A and C.
Subarea Area Runoff Product
ID acres Coeff.
A C" CA
input input input output
— ^ Pavement 0.20 100.00 20.00
Open 0.80 2.00 1.60
Gravel 0.03 40.00 1.20
Roof 0.00 90.00 0.00
sum: 1.03 sum: 22.80
Area-Weighted Runoff Coefficient(sum CA/sum A)= 22.14
"See sheet"Design Info"for inperviousness-based runoff coefficient values.
Messner Engineering,Inc. Page 10
CALCULATION:OF A PEAK RUNOFF USING RATIONAL METHOD
Project Title: Meiners Cluster P.U.D.
—
Catchment ID: PROPOSED SUB-BASIN'B' 5-yr.Peak Runoff Rate
I. Catchment Hydrologic Data
—
Catchment ID= B'
Area= 1.03 Acres
Percent Imperviousness= 22.14 %
NRCS Soil Type= B A, B,C, or D
—
II. Rainfall Informatlon I(inch/hr)=Cl *P1 /(C2+Td)^C3
• Design Storm Return Period, Tr= 5 years (input return period for design storm)
C1 = 28.50 (input the value of C1)
C2= 10.00 (input the value of C2)
_ C3= 0.786 (input the value of C3)
P1= 2.50 inches (input one-hr precipitation—see Sheet"Design Info")
M. Analysis of Flow Time(Time of Concentration)for a Catchment
Runoff Coefficient,C= 0.21
Overide Runoff Coefficient, C= (enter an ovedde C value if desired, or leave blank to accept calculated C.)
5-yr. Runoff Coefficient, C-5= 0.21
—
Overide 5-yr. Runoff Coefficient, C= (enter an overide C-5 value if desired,or leave blank to accept calculated C-5.)
Illustration
"erlaad LEGEND
Reach 1 flew.
_ Reach 2. O B` ueuag
new D4eetlea
Catluwent
— Reath 3 Bewdaey
NRCS Land Heavy Tillage/ Short Nearly Grassed Paved Areas 8
Type Meadow Field Pasture/ Bare Swales/ Shallow Paved Swales
— Lawns Ground Waterways (Sheet Flow)
Conveyance 2.5 5 7 10 15 20
Calculations: Reach Slope Length 5-yr NRCS Flow Flow
—
ID S L Runoff Convey- Velocity Time
Coen ante V Tr
ft/ft ft C-5 fps minutes
input input output input output output
—
Overland 0.0380 26 0.21 0.08 5.28
1 0.0230 430 15.00 2.27 3.15
2
3
4
5
Sum 456 Computed Tc= 8.43
Regional Tc= 12.53
—
IV.
Peak Runoff Prediction using Computed Tc lotion using Regional Tc
Rainfall Intensity at Tc, I= 7.21 inch/hr Rainfall Intensity at Tc, I= 6.16 inch/hr
Peak Flowrate, Qp= 1,55 cfs Peak Flowrate,Op= 1.32 cfs
—
— Messner Engineering,Inc. Page 11
CALCULATION OF A PEAK RUNOFF USING RATIONAL METHOD
Project Title: Meiners Cluster P.U.D.
_
Catchment ID: PROPOSED SUB-BASIN 18' 100-yr.Peak Runoff Rate
I. Catchment Hydrologic Data
Catchment ID= B'
Area= 1.03 Acres
Percent Imperviousness= 22.14 %
— NRCS Soil Type= B A, B, C,or D
II. Rainfall Information I(inch/hr)=C1 *P1 /(C2+Td)^C3
Design Storm Return Period,Tr= 100 years (input return period for design storm)
Cl = 28.50 (input the value of C1)
C2= 10.00 (input the value of C2)
— C3= 0.786 (input the value of C3)
P1= 4.50 inches (input one-hr precipitation—see Sheet"Design Info")
III. Analysis of Flow Time(Time of Concentration)for a Catchment
Runoff Coefficient, C= 0.45
Overide Runoff Coefficient, C= (enter an overide C value if desired,or leave blank to accept calculated C.)
5-yr. Runoff Coefficient, C-5= 0.21
_
Overide 5-yr. Runoff Coefficient, C= (enter an overide C-5 value if desired,or leave blank to accept calculated C-5.)
Illustration
overland LEGEND
Reach 1 flay
— Reach2. O B
aeumiaR
Flow Direction
• 4---
Catchment
--- Reach 3 BaunLD'
NRCS Land Heavy Tillage/ Short Nearly Grassed Paved Areas&
Type Meadow Field Pasture/ Bare Swales/ Shallow Paved Swales
— Lawns Ground Waterways (Sheet Flow)
Conveyance 2.5 5 7 10 I 15 20
Calculations: Reach Slope Length 5-yr NRCS Flow Flow
—
ID S L Runoff Convey- Velocity Time
Cool! ance V Tr
ft/ft ft C-5 fps minutes
input input output input output output
—
Overland 0.0380 26 0.21 0.08 5.28
1 0.0230 430 15.00 2.27 3.15
2
— 3
4
5
Sum 456 Computed To= 8.43
Regional Tc= 12.53
IV.
Peak Runoff Prediction using Computed Tc iction using Regional Tc
— Rainfall Intensity at Tc, I= 12.98 inch/hr Rainfall Intensity at Tc, I= 11.09 inch/hr
— Peak Flowrate, Qp= 5.99 cfs Peak Flowrate,Qp= 5.11 cfs
—
Messner Engineering,Inc. Page 12
Area-VVeighting for Runoff Coefficient Calculation
Project Title: Meiners Cluster P.U.D.
Catchment ID: PROPOSED SUB-BASIN 'C'
Illustration
eel
S
LEGEND:
Flow Direction
e® 4
S Cardlmear
Subaaa 3 Boundary
Instructions: For each catchment subarea,enter values for A and C.
_ Subarea Area Runoff Product
ID acres Coeff.
A C* CA
input input input output
— ^ Pavement 0.66 100.00 66.0O
Open 9.17 2.00 18.34
Gravel 0.32 40.00 12.80
Roof 0.32 90.00 28.80
sum: 10.47 Sum: 125.94
Area-Weighted Runoff Coefficient(sum CA/sum A)= 12.03
*See sheet"Design Info"for inperviousness-based runoff coefficient values.
Messner Engineering,Inc. Page 13
CALCULATION OF A PEAK RUNOFF USING RATIONAL METHOD
Project Title: Meiners Cluster P.U.D.
Catchment ID: PROPOSED SUB-BASIN'C' 5-yr.Peak Runoff Rate
I. Catchment Hydrologic Data
Catchment ID= C
Area= 10.47 Acres
Percent Imperviousness= 12.03 %
NRCS Soil Type= C A, B, C,or D
—
II. Rainfall information I(inchlhr)=C1 •P1 /(C2+Td)^C3
Design Storm Return Period,Tr= 5 years (input return period for design storm)
C1 = 28.50 (input the value of C1)
C2= 10.00 (input the value of C2)
— C3= 0.786 (input the value of C3)
P1= 2.50 inches (input one-hr precipitation—see Sheet"Design Info")
M. Analysis of Flow Time(Time of Concentration)for a Catchment
Runoff Coefficient, C= 0.22
Overide Runoff Coefficient, C= (enter an overide C value if desired, or leave blank to accept calculated C.)
5-yr. Runoff Coefficient, C-5= 0.22
Overide 5-yr. Runoff Coefficient, C= (enter an overide C-5 value if desired,or leave blank to accept calculated C-5.)
Illustration
overland LEGFTW
Reach 1 flaw
Reach 2' O Regbating
Flew Direction
E
Cathmant
— Reach 3 Beandexy
NRCS Land Heavy Tillage/ Short Nearly Grassed Paved Areas&
Type Meadow Field Pasture/ Bare Swabia/ Shallow Paved Swales
Lawns Ground Waterways (Sheet Flow)
Conveyance 2.5 5 [ 7 10 15 I 20
Calculations: Reach Slope Length 5-yr NRCS Flow Flow
— ID S L Runoff Convey- Velocity Time
Coeff ance V Tf
ft/ft ft CS fps minutes
input input output input output output
—
Overland 0.0240 500 0.22 0.31 26.58
1 0.0230 300 5.00 0.76 6.59
2 0.0140 175 15.00 1.77 1.64
3
4
5
Sum 975 Computed Tc= 34.81
Regional Tc= 15.42
—
IV.
Peak Runoff Prediction using Computed Tc Iction using Regional Tc
' . Rainfall Intensity at Tc, I= 3.59 inch/hr Rainfall Intensity at Tc, I= 5.60 inch/hr
_ Peak Flowrate, Op= 8.31 cfs Peak Fowrate,Op= 12.97 cfs
Messner Engineering,Inc. Page 14
CALCULATION OF A PEAK RUNOFF USING RATIONAL METHOD
Project Tide: Meiners Cluster P.U.D.
'— Catchment ID: PROPOSED SUB-BASIN 100-yr.Peak Runoff Rate
I. Catchment Hydrologic Data
Catchment ID= C
Area= 10.47 Acres
Percent Imperviousness= 12.03 %
NRCS Soil Type= C A, B, C, or D
II. Rainfall Information I(inch/hr)=C1 *P1 /(C2+Td)*C3
Design Storm Return Period,Tr= 100 years (input return period for design storm)
C1 = 28.50 (input the value of C1)
02= 10.00 (input the value of C2)
C3= 0.786 (input the value of C3)
P1= 4.50 inches (input one-hr precipitation—see Sheet"Design Info")
M. Analysis of Flow Time(Time of Concentration)for a Catchment
Runoff Coefficient, C= 0.54
Overide Runoff Coefficient, C= (enter an overide C value if desired,or leave blank to accept calculated C.)
5-yr. Runoff Coefficient, C-5= 0.22
Overide 5-yr. Runoff Coefficient, C= (enter an overide C-5 value if desired,or leave blank to accept calculated C-5.)
Illustration
�
LEGEND
Reach 1
Reach 2• Reim
iafl
new Diraifen
Catrhraaat
Reach) Boundary
NRCS Land Heavy Tillage/ Short Nearly Grassed Paved Areas&
Type Meadow Field Pasture/ Bare Swale& Shallow Paved Swabs
Lawns Ground Waterways (Sheet Flow)
Conveyance 2.5 I 5 I 7 10 15 20
Calculations: Reach Slope Length 5-yr NRCS Flow Flow
ID S L Runoff Convey- Velocity Time
Coeff ance V If
ftM ft CS fps minutes
input input output input output output
Overland 0.0240 500 0.22 0.31 26.58
1 0.0230 300 5.00 0.76 6.59
2 0.0140 175 15.00 1.77 1.64
3
4
5
Sum 975 Computed Tc= 34.81
Regional Tc= 15.42
IV.
Peak Runoff Prediction using Computed Tc Iction using Regional Tc
Rainfall Intensity at Tc, I = 6.46 inch/hr Rainfall Intensity at Tc, I= 10.08 inch/hr
Peak Flowrate,Op= 36.26 cfs Peak Flowrate, Qp= 56.62 cfs
"' Messner Engineering,Inc. Page 15
Area-Weighting for Runoff Coefficient Calculation
Project Title: Meiners Cluster P.U.D.
Catchment ID: PROPOSED SUB-BASIN
Illustration
SQ.t
LEGEND:
Flow Direction
ee
.� ° Catchment
Subarea 3 Boundary
Instructions: For each catchment subarea,enter values for A and C.
Subarea Area Runoff Product
ID acres Coeff.
A C* CA
input input input output
Pavement 0.06 100.00 6.00
Open 55.40 2.00 110.80
Gravel 0.05 40.00 2.00
Roof 0.08 90.00 7.20
sum: 55.59 sum: 126.00
Area-Weighted Runoff Coefficient(sum CAlsum A)= 2.27
*See sheet"Design Info"for inperviousness-based runoff coefficient values.
Messner Engineering,Inc. Page 16
•
CALCULATION OF A PEAK RUNOFF USING RATIONAL METHOD
Project Title: Meiners Cluster P.U.D.
Catchment ID: PROPOSED SUB-BASIN'D' 5-yr. Peak Runoff Rate
I. Catchment Hydrologic Data
Catchment ID= D
Area= 55.59 Acres
Percent Imperviousness= 2.27 %
NRCS Soil Type= C A, B, C,or D
II. Rainfall Information I(inch/hr)=C1 A PI /(C2+Td)AC3
Design Storm Return Period,Tr= 5 years (input return period for design storm)
C1 = 28.50 (input the value of C1)
C2= 10.00 (input the value of C2)
C3= 0.786 (input the value of C3)
P1= 2.50 inches (input one-hr precipitation—see Sheet"Design Info")
III. Analysis of Flow Time(Time of Concentration)for a Catchment
Runoff Coefficient, C= 0.16
Overide Runoff Coefficient, C= (enter an overide C value if desired,or leave blank to accept calculated C.)
5-yr. Runoff Coefficient, C-5= 0.16
Overide 5-yr. Runoff Coefficient,C= (enter an overide C-5 value if desired, or leave blank to accept calculated C-5.)
Illustration
eeerind •
LEGEND
Reach 1 Rev
Reach 2• 0 Begimring
Flew Direction
� E
Catchment
Rein 3 B...ndaq
NRCS Land Heavy Tillage/ Short Nearly Grassed Paved Areas&
Type Meadow Field Pasture/ Bare Swales/ Shallow Paved Swales
Lawns Ground Waterways (Sheet Flow)
Conveyance 2.5 5 7 10 15 20
Calculations: Reach Slope Length 5-yr NRCS Flow Flow
ID S L Runoff Convey- Velocity Time
Coeff ance V 11
ft/ft ft C-5 fps minutes
input input output input output output
Overland 0.0300 500 0.16 0.32 26.27
1 0.0180 1,082 5.00 0.67 26.88
2 0.0041 610 15.00 0.96 10.59
3
4
5
Sum 2,192 Computed Tc= 63.74
Regional To= 22.18
IV.
Peak Runoff Prediction using Computed Tc iction using Regional Tc
Rainfall Intensity at Tc, I= 2.43 inch/hr Rainfall Intensity at To, I= 4.65 inch/hr
Peak Flowrate, Qp= 22.23 oft Peak Flowrate, Qp= 42.67 cfs
—' Messner Engineering,Inc. Page 17
CALCULATION OF A PEAK RUNOFF USING RATIONAL METHOD •
Project Title: Meiners Cluster P.U.D.
Catchment ID: PROPOSED SUB-BASIN'D' 100-yr.Peak Runoff Rate
I. Catchment Hydrologic Data
Catchment ID= D
Area= 55.59 Acres
Percent Imperviousness= 227 %
NRCS Soil Type= C A, B, C,or D
II. Rainfall Information I(inch/hr)=C1 *P1 /(C2+Td)"C3
— Design Storm Return Period,Tr= 100 years (input return period for design stunn)
C1 = 28.50 (input the value of C1)
C2= 10.00 (input the value of C2)
C3= 0.786 (input the value of C3)
— P1= 4.50 inches (input one-hr precipitation—see Sheet"Design Info")
III. Analysis of Flow Time(lime of Concentration)for a Catchment
— Runoff Coefficient,C= 0.51
Overide Runoff Coefficient,C= (enter an overide C value if desired,or leave blank to accept calculated C.)
5-yr. Runoff Coefficient, C-5= 0.16
— Overide 5-yr. Runoff Coefficient, C= (enter an overide C-5 value if desired,or leave blank to accept calculated C-5.)
Illustration
aerial LEGEND
Reach 1 flaw
Reuh2• O Berry
— Flow Direttlor
Fa <--
Catchment
Reach 3 Boundary
NRCS Land Heavy Tillage/ Short Nearly Grassed Paved Areas&
Type Meadow Field Pasture/ Bare Swales/ Shallow Paved Swales
Lawns Ground Waterways (Sheet Flow)
—
Conveyance 2.5 5 7 10 15 20
Calculations: Reach Slope Length 5-yr NRCS Flow Flow
ID S L Runoff Convey- Velocity Time
_
Coeff ance V Tf
ftM ft C-5 fps minutes
input input output input output output
_ Overland 0.0300 500 0.16 0.32 26.27
1 0.0180 1,082 5.00 0.67 26.88
2 0.0041 610 15.00 0.96 10.59
3
— 4
5
Sum 2,192 Computed Tc= 63.74
Regional Tc= 22.18
— IV.
Peak Runoff Prediction using Computed Tc iction using Regional Tc
Rainfall Intensity at Tc, I= 4.37 inch/Fir Rainfall Intensity at Tc, I= 8.38 inch/Fir
Peak Flowrate,Op= 123.36 cfs Peak Flowrate, Op= 236.73 cfs
—
Messner Engineering,Inc. Page 18
Area-Weighting for Runoff Coefficient Calculation
Project Title: Meiners Cluster P.U.D.
Catchment ID: AREA TO LOT 2&3 DRIVEWAY CULVERTS
Illustration
— sure
LEGEND:
Flow Direction
Catchment
Subarea 3 Boundary
Instructions: For each catchment subarea,enter values for A and C.
Subarea Area Runoff Product
ID acres Coeff.
A C* CA
input input input output
— ^ Pavement 0.27 100.00 27.00
Open 0.61 2.00 1.22
Gravel 0.10 40.00 4.00
Roof 0.08 90.00 7.20
sum: 1.06 Sum: 39.42
Area-Weighted Runoff Coefficient(sum CA/sum A)= 37.19
*Se sheet"Design Info"for inperviousness-based runoff coefficient values.
Messner Engineering,Inc. Page 19
•
CALCULATION OF A PEAK RUNOFF USING RATIONAL METHOD
Project Title: Meiners Cluster P.U.D.
Catchment ID: DRIVEWAY CULVERTS FOR LOT 2 8 3 100-yr.Peak Runoff Rate
I. Catchment Hydrologic Data
Catchment ID= CULVERTS
Area= 1.06 Acres
Percent Imperviousness= 37.19 %
NRCS Soil Type= C A, B, C,or D
II. Rainfall Information I(inch/hr)=C1 *P1 /(C2+Td)AC3
Design Storm Return Period,Tr= 100 years (input return period for design storm)
C1 = 28.50 (input the value of C1)
C2= 10.00 (input the value of C2)
C3= 0.786 (input the value of C3)
P1= 4.50 inches (input one-hr precipitation—see Sheet"Design Info')
III. Analysis of Flow Time(Time of Concentration)for a Catchment
�- Runoff Coefficient,C= 0.58
Overide Runoff Coefficient, C= (enter an overide C value if desired,or leave blank to accept calculated C.)
5-yr. Runoff Coefficient, C-5= 0.34
Overide 5-yr. Runoff Coefficient, C= (enter an overide C-5 value if desired,or leave blank to accept calculated CS.)
Illustration
LEGEND
Reach 1
Reach 2• O Bepmrurg
Flyer Direction
� E
Catchment
Reach 3 Boundary
NRCS Land Heavy Tillage/ Short Nearly Grassed Paved Areas&
Type Meadow Field Pasture/ Bare Swales/ Shallow Paved Swales
Lawns Ground Waterways (Sheet Flow)
Conveyance 2.5 5 7 10 15 I 20 J
Calculations: Reach Slope Length 5-yr NRCS Flow Flow
ID S L Runoff Convey- Velocity Time
Coen ance V If
ft/ft ft C-5 fps minutes
input input output input output output
Overland 0.0857 35 0.34 0.15 4.02
1 0.0250 565 15.00 2.37 3.97
2
3
4
5
Sum 600 Computed Tc= 7.99
Regional Tc= 13.33
_ IV.
Peak Runoff Prediction using Computed Tc edlction using Regional Tc
Rainfall Intensity at Tc, I= 13.23 inch/hr Rainfall Intensity at Tc, I= 10.79 inch/hr
Peak Flowrate, Qp= 8.11 cfs Peak Flowrate, Qp= 6.61 cfs
Messner Engineering,Inc. Page 20
Area-Weighting for Runoff Coefficient Calculation
Project Title: Meiners Cluster P.U.D.
Catchment ID: AREA TO LOT 4&5 DRIVEWAY CULVERTS
Illustration
— s
LEGEND:
Flow Direction
SoVitt
Subama 3 Carcbm eat
Boundary
Instructions: For each catchment subarea,enter values for A and C.
Subarea Area Runoff Product
ID acres Coeff.
A C* CA
input input input output
Pavement 0.33 100.00 33.00
Open 5.30 2.00 10.60
Gravel 0.15 40.00 6.00
— Roof 0.16 90.00 14.40
sum: 5.94 sum: 64.00
Area-Weighted Runoff Coefficient(sum CA/sum A)= 10.77
— *See sheet"Design Info"for inperviousness-based runoff coefficient values.
— Messner Engineering,Inc. Page 21
CALCULATION OF A PEAK RUNOFF USING RATIONAL METHOD
•
•
Project Title: Meiners Cluster P.U.D.
Catchment ID: DRIVEWAY CULVERTS FOR LOT 4&5 100-yr. Peak Runoff Rate
I. Catchment Hydrologic Data
Catchment ID= CULVERTS
Area= 5.94 Acres
Percent Imperviousness= 10.77 %
NRCS Soil Type= C A, B, C,or D
II. Rainfall Information I(inchlhr)=C1 *P1 /(C2+Td)^C3
Design Storm Return Period,Tr= 100 years (input return period for design storm)
C1 = 28.50 (input the value of C1)
C2= 10.00 (input the value of C2)
C3= 0.786 (input the value of C3)
._ P1= 4.50 inches (input one-hr precipitation—see Sheet"Design Info")
III. Analysis of Flow Time(Time of Concentration)for a Catchment
Runoff Coefficient, C= 0.53
Overide Runoff Coefficient, C= (enter an overide C value if desired, or leave blank to accept calculated C.)
5-yr. Runoff Coefficient, C-5= 0.21
Overide 5-yr. Runoff Coefficient, C= (enter an overide C-5 value if desired, or leave blank to accept calculated C-5.)
Illustration
�
LEGEND
Reach 1
Reach 2• O &eni g
-- flmv Direction
4(-
Catchment
Reach) Beanaary
NRCS Land Heavy Tillage/ Short Nearly Grassed Paved Areas&
Type Meadow Field Pasture/ Bare Swale& Shallow Paved Swales
Lawns Ground Waterways (Sheet Flow)
Conveyance 2.5 5 7 10 15 20
Calculations: Reach Slope Length 5-yr NRCS . Flow Flow
_ ID S L Runoff Convey- Velocity Time
Coeff ance V TT
ft/ft ft C-5 fps minutes
input input output input output output
_ Overland 0.0150 500 0.21 0.27 31.27
1 0.0814 43 5.00 1.43 0.50
2 0.0230 625 15.00 2.27 4.58
3
4
5
Sum 1,168 Computed Tc= 36.35
Regional Tc= 16.49
IV.
Peak Runoff Prediction using Computed Tc iction using Regional Tc
Rainfall Intensity at Tc, I= 6.29 inch/hr Rainfall Intensity at Tc, I= 9.76 inch/hr
Peak Flowrate, Qp= 19.92 cfs Peak Flowrate, Qp= 30.92 cfs
Messner Engineering,Inc. Page 22
DETERMINE:SIZE OF DRIVEWAY CULVERT:FOR LOTS 2& 3
(Qtoo = 8.11 c.f.s. See Page 20 .)
(Results from CULVERTMASTER, Haestad Methods, Inc.)
Culvert Summary
Allowable HW Elevation 0.00 ft Headwater Depth/Height 1.38
Computed Headwater Elevation 102.07 ft Discharge 8.11 cfs
Inlet Control HW Elev 101.82 ft Tailwater Elevation 0.00 ft
Outlet Control HW Elev 102.07 ft Control Type Outlet Control
Grades
Upstream Invert 100.00 ft Downstream Invert 99.70 ft
Length 30.00 ft Constructed Slope 0.010000 ft/ft
Hydraulic Profile
Profile CompositeM2Pressure Depth,Downstream 1.10 ft
Slope Type Mild Normal Depth N/A ft
Flow Regime Subcritical Critical Depth 1.10 ft
— Velocity Downstream 5.82 ft/s Critical Slope 0.025597 ft/ft
Section
- Section Shape Circular Mannings Coefficient 0.024
Section Material CMP Span 1.50 ft
Section Size 19 inch Rise 1.50 ft
Number Sections 1
Outlet Control Properties
Outlet Control HW Elev 102.07 ft Upstream Velocity Head 0.33 ft
Ke 0.50 Entrance Loss 0.16 ft
Inlet Control Properties
Inlet Control HW Elev 101.82 ft Flow Control Transition
Inlet Type Headwall Area Full 1.8 ft'
K 0.00780 HDS 5 Chart 2
M 2.00000 HDS 5 Scale 1
C 0.03790 Equation Form 1
Y 0.69000
Messner Engineering, Inc. Page 23
DETERMINE SIZE OF DRIVEWAY CULVERT FOR LOTS 4 & 5' I
(Q100 = 19.92 c.f s. See Page 22 .)
(Results from CULVERTMASTER, Haestad Methods, Inc.)
•
Culvert Summary
Allowable HW Elevation 0.00 ft Headwater Depth/Height 1.17
_ Computed Headwater Elevation 102.64 ft Discharge 19.92 cfs
Inlet Control HW Elev 102.46 ft Tailwater Elevation 0.00 ft
Outlet Control HW Elev 102.64 ft Control Type Outlet Control
Grades
Upstream Invert 100.00 ft Downstream Invert 99.70 ft
Length 30.00 ft Constructed Slope 0.010000 ft/ft
Hydraulic Profile
Profile M2 Depth,Downstream 1.56 ft
Slope Type Mild Normal Depth N/A ft
Flow Regime Subcritical Critical Depth 1.56 ft
Velocity Downstream 6.76 ft/s Critical Slope 0.020559 ft/ft
Section
Section Shape Circular Mannings Coefficient 0.024
Section Material CMP Span 2.25 ft
Section Size 27 inch Rise 2.25 ft
Number Sections 1
Outlet Control Properties
Outlet Control HW Elev 102.64 ft Upstream Velocity Head 0.46 ft
Ke 0.50 Entrance Loss 0.23 ft
Inlet Control Properties
Inlet Control HW Elev 102.46 ft Flow Control Unsubmerged
Inlet Type Headwall Area Full 4.0 ft'
K 0.00780 HDS 5 Chart 2
M 2.00000 HDS 5 Scale 1
C 0.03790 Equation Form 1
Y 0.69000
Messner Engineering, Inc. Page 24
- DETERMINE;SIZE"OFCULVERTAT.W:C.R.?:100
(Q100 = 5.99 c.f.s. See Page 12 .)
(Results from CULVERTMASTER, Haestad Methods, Inc.)
Culvert Summary
Allowable HW Elevation 0.00 ft Headwater Depth/Height 1.03
Computed Headwater Elevation 5,444.29 ft Discharge 5.99 cfs
— Inlet Control HW Elev 5,444.18 ft Tailwater Elevation 0.00 ft
Outlet Control HW Elev 5,444.29 ft Control Type Outlet Control
— Grades
Upstream Invert 5,442.75 ft Downstream Invert 5,441.25 ft
Length 75.00 ft Constructed Slope 0.020000 ft/It
Hydraulic Profile
Profile M2 Depth,Downstream 0.95 ft
_ Slope Type Mild Normal Depth 0.96 ft
Flow Regime Subcritical Critical Depth 0.95 ft
Velocity Downstream 5.10 ft/s Critical Slope 0.021176 ft/ft
— .-.
Section
Section Shape
Circular Mannings Coefficient 0.024
Section Material CMP Span 1.50 ft
— Section Size 18 inch Rise 1.50 ft
Number Sections 1
— Outlet Control Properties
Outlet Control HW Elev 5,444.29 ft Upstream Velocity Head 0.39 ft
Ke 0.50 Entrance Loss 0.19 ft
Inlet Control Properties
Inlet Control HW Elev 5,444.18 ft Flow Control Unsubmerged
— Inlet Type Headwall Area Full 1.8 ft'
K 0.00780 HDS 5 Chart 2
M 2.00000 HDS 5 Scale 1
C 0.03790 Equation Form 1
— y 0.69000
Messner Engineering, Inc. Page 25
- DETERMINE SIZE OFDRAINAGESWALE ?
(Q100- 36.26 c.f.s. See Page 15 .)
(Results from FLOWMASTER, Haestad Methods, Inc.)
Input Data
Mannings Coefficient 0.030
Channel Slope 0.013000 ft/ft
Left Side Slope 4.000000 H :V
Right Side Slope 4.000000 H :V
Discharge 36.30 cfs
Results
Depth 1.43 ft
Flow Area 8.20 ftf
Wetted Perimeter 11.80 ft
Top Width 11.45 ft
Critical Depth 1.39 ft
Critical Slope 0.015430 ft/ft
Velocity 4.43 ft/s
Velocity Head 0.30 ft
Specific Energy 1.74 ft
Froude Number 0.92
Flow is subcritical.
Messner Engineering, Inc. Page 26
APPENDIX II
CHARTS, GRAPHS,
FIGURES AND DETAILS
Table 4.4.1.3-2
— Runoff Curve Numbers for Hydrologic
Soil-Cover Complexes--Rural Conditions
(Antecedent Moisture Condition II, and Ia - 0.2 S)
(From: U. S. Dept. of Agriculture,
Soil Conservation Service, 1977)
Cover Runoff curve number
—
treatment Hydrologic by Hydrologic soil group
Land use or practice condition A B C D
Fallow Straight row ---- 77 86 91 94
Row crops If Poor 72 81 88 91
— " Good 67 78 85 89
Contoured - Poor 70 79 84 88
" Good 65 75 82 86
' "and terraced Poor 66 74 80 82
— " " Good 62 71 78 81
Small Straight row Poor 65 76 84 88
— grain Good 63 75 83 87
Contoured Poor 63 74 82 85
Good 61 73 81 84
"and terraced Poor 61 72 79 82
— Good 59 70 78 81
Close-seeded Straight row Poor 66 77 85 89
— legumes 1/ " o
_ Good 58 72 81 85
or Contoured Poor 64 75 83 85
rotation " Good 55 69 78 83
meadow "and terraced Poor 63 73 80 83
— "and terraced Good 51 67 76 80
Pasture Poor 68 79 86 89
or range Fair 49 69 79 84
Good 39 61 74 80
Contoured Poor 47 67 81 88
" Fair 25 59 75 83
" Good 6 35 70 79
—
Meadow Good 30 58 71 78
Woods Poor 45 66 77 83
Fair 36 60 73 79
Good 25 55 70 77
Farmsteads ---- 59 74 82 86
Roads (dirt) 2/ ---- 72 82 87 89
— (hard surface) 2/ ---- 74 84 90 92
r
1/ Close-drilled or broadcast
J 2/ Including right-of-way
LCS-WM Manual 4.4---9 April 1979
.1 .2 .3 .5 1 2 3 5 10 20
50 50
0
30 0 4 30
0 i.
z �4, 02 v
0 20 0 ` 0 20
z g ti v
Q- . 0 2 S2
'V 3
v CD
Cl to
P
w 10
�
CI-
0 �• PJ @ O 40 10
O P
-J �P = aQ U4. ?
k ce
U 5 A. 3-
O ¢ mP 3P �P 5
ct u O ti J o O
O 40 4P hr 211 cae QP
tt 3 3
w
Q
2 2
— I 1
.5 .5
.I .2 .3 .5 I 2 3 5 10 20
VELOCITY IN FEET/ SECOND
Figure 4.4.1.4—I AVERAGE VELOCITIES FOR ESTIMATING TRAVEL
— TIME FOR OVERLAND FLOW.
(From : USDA, Soil Conservation Service, 1977)
— 4.4---14
0.7 0.9
0.1 0.2 0.3 0.4 0.5 0.6 0.8 1 2 3 4 5 6 7 8 910
1000
900
800
700
600
500
400
TYPE II-A For Areas
300 Betwean 6000'—BOOJ.
TYPE II For A eos
Above 8000'
200
— z
100
90
w 80
70 -
— i 60
V
50
5
x 40
w
a. 30
20
10
0.1 0.2 0.3 0.4 05 0.6070.91 2 3 • 4 5 6 7 8 9 10
TIME OF CONCENTRATION (Tc)— HOURS
Figure 4.4.4 —I PEAK DISCHARGE IN CSM/INCH OF RUNOFF VS.
TIME OF CONCENTRATION ; TYPE U STORM DISTRIBUTION
AND TYPE IE-A STORM DISTRIBUTION.
(From : USDA, Soil Conservation Service , 1977)
4.4---20
DRAINAGE CRITERIA MANUAL (V. 1) RUNOFF
TABLE RO-3
Recommended Percentage Imperviousness Values
Land Use or Percentage
Surface Characteristics Imperviousness
Business:
Commercial areas 95
Neighborhood areas 85
Residential:
Single-family '
Multi-unit (detached) 60
Multi-unit (attached) 75
Half-acre lot or larger '
Apartments 80
Industrial:
Light areas 80
Heavy areas 90
Parks, cemeteries 5
— Playgrounds 10
Schools 50
Railroad yard areas 15
Undeveloped Areas:
Historic flow analysis 2
Greenbelts, agricultural 2
_ ^ Off-site flow analysis 45
(when land use not defined)
Streets:
Paved 100
Gravel (packed) 40
Drive and walks 90
Roofs 90
Lawns, sandy soil 0
Lawns, clayey soil 0
See Figures RO-3 through RO-5 for percentage imperviousness.
Based in part on the data collected by the District since 1969, an empirical relationship between C and
the percentage imperviousness for various storm return periods was developed. Thus, values for C can
be determined using the following equations (Urbonas, Guo and Tucker 1990).
CA = KA + (1.3li3 — 1.4412 + 1.135i- 0.12) for CA ≥ 0, otherwise CA = 0 (RO-6)
CCD = KCD + (0.858i' - 0.786i2 + 0.774i+ 0.04) (RO-7)
Cs - (CA + Ca,)/2
in which:
— = % imperviousness/100 expressed as a decimal (see Table RO-3)
06/2001 RO-9
Urban Drainage and Rood Control District
RUNOFF DRAINAGE CRITERIA MANUAL (V. 1)
CA = Runoff coefficient for Natural Resources Conservation Service (NRCS)Type A soils
CB = Runoff coefficient for NRCS Type B soils
CcD = Runoff coefficient for NRCS Type C and D soils
KA = Correction factor for Type A soils defined in Table RO-4
KcD = Correction factor for Type C and D soils defined in Table RO-4
TABLE RO-4
Correction Factors Ka and Km for Use With Equations RO-6 and RO-7
Storm Return Period
NRCS Soil Type
2-Year 5-Year 10-Year 25-Year 50-Year 100-Year
C and D 0 -0.10i+0.11 -0.181+ 0.21 -0.281+ 0.33 -0.331+ 0.40 -0.391+ 0.46
A 0 -0.081+ 0.09 -0.14i+ 0.17 -0.191+ 0.24 -0.221+ 0.28 -0.251+0.32
The values for various catchment imperviousnesses and storm return periods are presented graphically in
— Figures RO-6 through RO-8, and are tabulated in Table RO-5. These coefficients were developed for the
Denver region to work in conjunction with the time of concentration recommendations in Section 2.4. Use
of these coefficients and this procedure outside of the semi-arid climate found in the Denver region may
— not be valid.
See Examples 7.1 and 7.2 that illustrate the Rational method. The use of the Rational method in storm
sewer design is illustrated in Example 6.13 of the STREETS/INLETS/STORM SEWERS chapter.
RO-10 06/2001
Urban Drainage and Flood Control District
DRAINAGE CRITERIA MANUAL (V. 1) RUNOFF
- TABLE RO-5
Runoff Coefficients, C
- Percentage
Imperviousness Type C and D NRCS Hydrologic Soil Groups
2-yr 5-yr 10-yr 25-yr 50-yr 100-yr
0% 0.04 0.15 0.25 0.37 0.44 0.50
-
5% 0.08 0.18 0.28 0.39 0.46 0.52
10% 0.11 0.21 0.30 0.41 0.47 0.53
15% 0.14 0.24 0.32 0.43 0.49 0.54
- 20% 0.17 0.26 0.34 0.44 0.50 0.55
25% 0.20 0.28 0.36 0.46 0.51 0.56
30% 0.22 0.30 0.38 0.47 0.52 0.57
- 35% 0.25 0.33 0.40 0.48 0.53 0.57
40% 0.28 0.35 0.42 0.50 0.54 0.58
45% 0.31 0.37 0.44 0.51 0.55 0.59
50% 0.34 0.40 0.46 0.53 0.57 0.60
_
55% 0.37 0.43 0.48 0.55 0.58 0.62
60% 0.41 0.46 0.51 0.57 0.60 0.63
65% 0.45 0.49 0.54 0.59 0.62 0.65
-
70% 0.49 0.53 0.57 0.62 0.65 0.68
75% 0.54 0.58 0.62 0.66 0.68 0.71
80% 0.60 0.63 0.66 0.70 0.72 0.74
- -- 85% 0.66 0.68 0.71 0.75 0.77 0.79
90% 0.73 0.75 0.77 0.80 0.82 0.83
95% 0.80 0.82 0.84 0.87 0.88 0.89
- 100% 0.89 0.90 0.92 0.94 0.95 0.96
Type B NRCS Hydrologic Soils Group
0% 0.02 0.08 0.15 0.25 0.30 0.35
5% 0.04 0.10 0.19 0.28 0.33 0.38
-
10% 0.06 0.14 0.22 0.31 0.36 0.40
15% 0.08 0.17 0.25 0.33 0.38 0.42
20% 0.12 0.20 0.27 0.35 0.40 0.44
- 25% 0.15 0.22 0.30 0.37 0.41 0.46
30% 0.18 0.25 0.32 0.39 0.43 0.47
35% 0.20 0.27 0.34 0.41 0.44 0.48
- 40% 0.23 0.30 0.36 0.42 0.46 0.50
45% 0.26 0.32 0.38 0.44 0.48 0.51
50% 0.29 0.35 0.40 0.46 0.49 0.52
55% 0.33 0.38 0.43 0.48 0.51 0.54
-
60% 0.37 0.41 0.46 0.51 0.54 0.56
65% 0.41 0.45 0.49 0.54 0.57 0.59
70% 0.45 0.49 0.53 0.58 0.60 0.62
75% 0.51 0.54 0.58 0.62 0.64 0.66
80% 0.57 0.59 0.63 0.66 0.68 0.70
' 85% 0.63 0.66 0.69 0.72 0.73 0.75
- 90% 0.71 0.73 0.75 0.78 0.80 0.81
95% 0.79 0.81 0.83 0.85 0.87 0.88
100% 0.89 0.90 0.92 0.94 0.95 0.96
- 06/2001 RO-11
Urban Drainage and Flood Control District
RUNOFF DRAINAGE CRITERIA MANUAL (V. 1)
TABLE RO-5 (CONTINUED) l
Runoff Coefficients, C
— Percentage
Imperviousness Type A NRCS Hydrologic Soils Group
2-yr 5-yr 10-yr 25-yr 50-yr 100-yr
0% 0.00 0.00 0.05 0.12 0.16 0.20
5% 0.00 0.02 0.10 0.16 0.20 0.24
10% 0.00 0.06 0.14 0.20 0.24 0.28
15% 0.02 0.10 0.17 0.23 0.27 0.30
- 20% 0.06 0.13 0.20 0.26 0.30 0.33
25% 0.09 0.16 0.23 0.29 0.32 0.35
30% 0.13 0.19 0.25 0.31 0.34 0.37
35% 0.16 0.22 0.28 0.33 0.36 0.39
40% 0.19 0.25 0.30 0.35 0.38 0.41
45% 0.22 0.27 0.33 0.37 0.40 0.43
50% 0.25 0.30 0.35 0.40 0.42 0.45
-
55% 0.29 0.33 0.38 0.42 0.45 0.47
60% 0.33 0.37 0.41 0.45 0.47 0.50
65% 0.37 0.41 0.45 0.49 0.51 0.53
70% 0.42 0.45 0.49 0.53 0.54 0.56
75% 0.47 0.50 0.54 0.57 0.59 0.61
80% 0.54 0.56 0.60 0.63 0.64 0.66
85% 0.61 0.63 0.66 0.69 0.70 0.72
90% 0.69 0.71 0.73 0.76 0.77 0.79
95% 0.78 0.80 0.82 0.84 0.85 0.86
100% 0.89 0.90 0.92 0.94 0.95 0.96
-
- RO-12 06/2001
Urban Drainage and Flood Control District
DRAINAGE CRITERIA MANUAL (V. 1) RUNOFF
—
50
— 30
i
H 20 13 4 /�
Z o° •w 4 ✓
W W •O? aW
et s 4.
w 4 a' :y
a 10 4 ` 3
a.
4W 1 ? 3' t
w , Ji v v .4..? 4,
C! 4'4 4
—
a a . r
40 av 4—J O et; f
co 5 4 A. J� 4 !4 y 3 O
W a 4 . �
— cn : ii a V. V4f W
cc 3
O 3 3 io
U 2 a o n
W
W 4
H 4
Y 4r I . r
Cr 44 O
— 1 4•
5 I l l 1
.1 .2 .3 .5 1 2 3 5 10 20
VELOCITY IN FEET PER SECOND
—
FIGURE RO-1
Estimate of Average Overland Flow Velocity for Use With the Rational Formula
06/2001 RO-13
Urban Drainage and Flood Control District
Hello