1994-07-28 Plat Review
..
MEYER-ROHLIN, INC.
ENGINEERS-LAND SURVEYORS 1111 Hwy. 25 N., Buttalo, Minn. 55313 Phone 612 - 682-1781
July 28, 1994
Mr. Dale Powers
City of Albertville
PO Box 131
Albertville, MN 55301
RE: psyk/Marx Drainage
Dear Dale:
In an attempt to get City Council approval of the psyk 6th
Addition plat, we are submitting the following for your review:
1. Exhibit "A" is a composite copy of the topography flown in
November, 1981, and the field surveyed topography by Meyer-
Rohlin, Inc. in December, 1972. This would be the topography
prior to any development work in the area and represents the
pre-development drainage patterns. On this exhibit we have
delineated by extra heavy lines the drainage areas that
originally surface drained through the psyk property to the
wetlands on the Marx property. The area outlined in yellow is
that portion of the above drainage area that is contained in
the psyk 5th and 6th Additions and potential future psyk
additions to the west, and approximates 26.37 acres. Runoff
calculations based on the S.C.S. TR55 method, for the psyk
portion only, are enclosed based on the original soi 1 and
farming conditions (row crops) and summarized as follows:
storm Event
1 year
2 year
5 year
10 year
Peak Runoff
11.29 cfs
15.99 cfs
25.8 cfs
33.8 cfs
Total Volume
1.78 ac. ft.
2.42 ac. ft.
3.78 ac. ft.
4.86 ac. ft.
2. With the design of the psyk 5th and 6th Additions, and
potential future additions to the west, a drain-dry detention
pond is being utilized outletting to the south into a
sedimentation pond before entering the large psyk area
wetlands. Exhibit "B" indicates this detention pond, outlet-
ting to the south and the greatly reduced area which will
continue draining to the northeast. The area draining to the
northeast following the original drainage pattern from the
designed 5th, 6th and future additions to the west has been
reduced from the above 26.37 acres to 7.9 acres. The runoff
Thore P. Meyer, Professional Engineer Robert Rohlin, Licensed Land Surveyor
calculations for this 7.9 acre parcel, based on the SCS-TR 55
Method, are enclosed, based on the residential, 1/3 acre
sites and are summarized as follows:
storm Event
2 year
10 yr
50 year
Peak Runoff
4.97 cfs
12.7 cfs
20.3 cfs
3. The detention pond design is based on controlling the peak
runoffs from the major storm and releasing the storm water at
a rate equal to or less than the runoff from the pre-
development drainage pattern. In this case, wi th a culvert
designed to restrict the outlet flow from the detention pond
to a rate of 15.99 cfs. (Peak flow from the 26.37 acres for
the 2 year storm event based on pre-development conditions).
As per the calculation sheets, for the 100-year storm event
this would require a detention pond of 0.43 acre/feet storage
capaci ty. By using the northeasterly lot of the psyk 6th
Addi tion as a temporary detention pond, approximately 0.55
acre/feet of storage is provided. (Bottom elevation of 953.3
and an overflow berm of 955.3). Other combinations of outfall
rate and detention pond storage can be used; i . e. lower
outlet flow from the pond with an overflow of the detention
pond berm at a storm event less than 100 years.
In any case, this is the natural flow from the Psyk and Marx
property that is proposed to be controlled by a restricting
culvert and a temporary detention pond. The delineation of the
Marx wetland areas, certainly being needed before any develop-
ment of the Marx property could begin, has no bearing upon the
psyk 6th Addition. Mr. psyk has been held up on this project for
months, while much time and effort has been spent attempting to
work out an amiable agreement with Mr. Marx. The current
proposal protects the Marx property to a much greater degree
than existing and past conditions until such time that the Marx
property would be developed. At that time the needed storm sewer
systems would be installed on a pro-rata cost basis as has been
discussed for the past few months.
If you have any questions, please feel free to contact myself or
Norman Gartner of our office. We trust that some positive action
can be taken regarding the approval of the psyk 6th Addition at
the next Albertville Council meeting.
Sincerely,
cc: Mike Couri
Bob Robertson, RCM
Doug PSrk
File 94 20
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No topography available
Meyer-Hohlincrew
lopograIJhy*Dcc., 1972
~>
'"~
'0
1,"'00
Exhibit A
ORIGINAL TOPOGRAPHY
FIOU(.IA.L
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...
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-rr--r-
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......"l. L. I
54 1/2 Street!\.' E.
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---
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Exhlbit B
PROPOSED DEVELOPMENT
{'J
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""'r
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'---'
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-T
cD
-r-
\Vorksheet 2: Runoff curve number and runoff
~
P. \) \
rOJect \.~...,~'/
If)", "'-, '
~_- " _._,. - d._.'- ~:::>~_.
Location
~ I.
f\! "'~"'_
,__- ;,~._ '<,.-I
, ~,~~ ___L....., / ! :....._!_ ~?_
By i J;;/J.
----rI
Checked
Da te i~" 2 2 ~0 4
Ci rc Ie one: /"P;;;;;rl
'.----~
\
Developed
Date
1. Runoff curve number (CN)
n I
( <2 r Q :z. -h 1'-: c' ; )0-~<v,"_,.,(;~t':'. 1/ ~? i' ""-;:;:::':0;/ /,~
1\ _,~ I 'I i " ;'
i~{; f!l:,'.- TV pc; - I) (} / f
11ft iZ FiE..lO j~fo -f}c::(_ (11'-
Soil name Cover description CN 1./ Area Product
and of
hydrologic (cover type, treiitment, and C',j ~es CN x area
hydrologic condition; I M -:r
group N I I
percent impervious; N N Omi2
C)
unconnected/connected impervious M 0%
..0 co co
(appendix A) area riltio) co 'rl 'M
E-< >=.. >=..
/-t~, '1 f/CU '- I
~ t'f(\'(<::;"~t:.o
O~) 1~ 1,05 11.1
Ht. w D<::..J ~
1::"'0 '-V c.. \206 <;: . / r;-sL. Z.
I
'( ') ~2t! ! f-, '" j.. gl Iq.ZL
,,5 eo''"' , - GO ~ 12
,
'J),)W~C:.'> I2c <.U C ~o6 4,3 34g,~
I
(6) ~-+. i20 VJ ~ P0Ji~ gl
~ VCU-I
i),.; '-'Ok '" (0; ~ '2"'f S /.8
s,+. ~tJ-I' rC;ooo &'1 I~O, 2..-
I
1/ Use only one CN source per 11 ne. Totals = z..C. S7 2-!~:;.{)
CN (weighted)
total product
total area
Zl!~
&-( . 2-/
Use CN
a-)
V.....~I
2. Runoff
Frequency ..............................
Storm t/l Storm 1/2 Storm i/3
I '2 S- /0
yr
in 2.,3 2.1 5.~ t/./
in 0. g, J./(!) ;,7'2- 2.2/
Rainfall. P (24-hour) ..................
Runoff) Q ..............................
(Use P and eN with table 2-1, fig. 2-1.
or eqs. 2-) and 2-4.)
D.2
(21O.VI.TR.55, Second Ed., June 1986)
\Vorksheet 3: Time of concentration (T c) or travel time (Tt)
n
Project r~';"\(. O""'J~LC."::,'hC.\ ,'\
I
Lo cat ion }i-<__~; <!.o~'--l'1l1 :..- L- C
I
By -,-OIA. Da te fa. 2 2 . ~4,
"TT---"
Checked ______ Date
Circle one:~ Developed
Circle one: Tc Tt through subarea
NOTES: Space for as ~any as two segments per flow type can be used for each
worksheet.
Include a ~p, schematic, or description of flow segments'f
I
Sheet flow (Applicable to Tc only)
1. Surface description (table 3-1)
Segment ID
............. .
2. Manning's roughness coeff., n (table 3-1) ..
3. Flow length, L (total L < 300 ft) ..........
4. Two-yr 24-hr rainfall, P2 ..................
5.
Land slope, s .............................. ft/ft
0: 0.007 (nL)0.8
T 0 4 Compute Tt ...... hr
t P 0.5 .
2 s
6.
Shallow concentr3ted flow
Segment ID
7. Surface .description (paved or unpaved) .....
.8. Flow length, L ............................. ft
9. Watercourse slope, s ....................... ft/ft
10. Average velocity, V (figure 3-1) ...........
ft/s
L
11. Tt m 3600 V
Compute Tt ......
Channel flow
Segment ID
12.
Cross sectional flow area, a
ft2
.............. .
13. Wetted perimeter, Pw....................... ft
14.
a
r ..-
PI.'
Hydraulic radius,
Compute r .......
15. Channel slope, s ........................... ft/ft
16.
Manning's roughness coeff., n ..............
1 49 2/3 1/2
V.. . r s Compute V.......
n
ft/s
17.
18.
Flow length, L
ft
. . . . . . . . . . . . . . .. . . . . . . . . . . . . . .
19.
L
3600 V
. . . . . .
hr
\.,Tatershed or subarea Tc or Tt (add Tt in steps 6,11, and 19) ........
1+ l
T ..
t
Compute Tt
20.
/
(21O-VI-TR.55, Second Ed., June 1986)
J LfE/2.tJiJ1t.
CUI-i
GUlT:
So {(..'>
<",,<>( '/
.?v 1:1 h<'S
~O:i-S
.. c!I' .,
< LO ,0 ~t:;t,
ft
CJ.6&, 0.0G
/50 300
2..{ '2-.1
in
,O'Z- ,03
~'rz] I ,Ig
.~
(!.ull \.;, I~ C;ud. )'''1(.$
u
u
" (
I!ou~
o:~
I&~ /500 ,-
y .._ U)emfy/ (.oC!s)
.@O2.'{~ ,0(.;2\'
/,J~ 1~/6
(,t/;ll t 3/
~,--------
hr
ft
=QQJ
hr - fij
D-3
\Vorksheet 4: Graphical Peak Discharge method
Project
C6.~\#
\{ ..... \ l
rL_ '.". \
j /"-=--,-,,,)',:"'-'"-; (_-::f~':\\" ~t~~, \'1"'
\
Location
j~\.""" F~.-::"::'J:~~~\j!. L L_ c7-
~-........
Circle one:~ Developed
1. Data: ~
,O~rL
Drainage area ....~q-P.. A =
m
Runoff curve number ... . eN = &,
Time of concentration . . Tc = ,b-Z-
Ra in fall distribution type = IF
Pond and swamp areas spread II ~ /0
throughout watershed ..... . =
2.
Frequency
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
3.
Rainfall ,
P (2-i-hour) ...................
4.
Initial abstraction, I.................
a
(Use C~ with table 4-1.)
5.
Compute I Ip
a
.......................... ..
6.
Unit peak discharge, q .................
u
(Use T and I IP with exhibit 4-~ )
c a
7.
Runoff, Q ...............................
(From worksheet 2).
8.
Pond
(Use
with
and swamp adjustment factor, F
p
percent pond and swamp area
table 4-2. Factor is 1.0 for
percent pond and swamp area.)
zero
9. Peak discharge, q ......................
p
(Where q = q A QF )
P u m p
By --rD/i,
~
Checked
mi2 (acres/640)
(From worksheet 2)
hr (From worksheet 3)
cr, lA, II, III)
Date {.,;., ;2 2 0;i4
Date
percent of A (2.9 acres or mi2 covered)
m ---;-
Storm III
yr
2-
Z,1
in
in I
I
I
in I
,t/b9 I
t 11 ~71
1Cf() I
/. 10 I
csmlin
((1JAx) L1~1
Storm #2 Storm #3
s-
S.6
I/~q I
//510 I
S-6~ I
t1Z I
nz. I
10
4, i
2.3
I t/01 I, :/&7
//44 112'0-$1
5]6 I 410
2.2-1 I (j~ &- J
,17- I t 17-
cfs I J ::;ot1 I 2";: 71 I oS 5.7(, I n.2.9
-r~ 1?ul..16Fl=' J ." () )( 4m x0:S. ~~ (~c.~) 2.4'2
fL 0~~ f)
D-4
(210-VI.TR-55, Second Ed., June 1986)
:So '7 ~
4-81..
/,1&
Project
Location
Circle one:
\Vorksheet 2: Runoff curve number and runoff
c---'
........,{.., ,
\ ":::) !",,.I'C,. ~
/
z."..""
! .
,j~ o:--,:::_',~" ~""( r- ,'_~_
/j~_ p::::...,~-
I
-:\~! :'-__l",._~t:;
,..~~->~-~-"'~
present<Deve1op~
"'------.--
1. Runoff curve number (CN)
Soil name
and
hydrologic
group
(appendix A)
4IOJ-(T;' C ~-.J
( 6'\
,,~. .J
Cover description
(cover type, treatment, and
hydrologic condition;
percent impervious;
unconnected/connected impervious
area p.tio)
Dc=:' c i .
1'-.:-;; I T) ;;;:: '---"";- ! ;~-~
if ~ f\e-r:zr l~<;
l! Use only one CN source per line.
CN (weighted)
2. Runoff
Frequency
Rainfall,
total product
total area
. ..... ...... .... ... ...........
yr
P (24-hour) ..................
in
Runoff) Q .............................. in
(Use P and CN with table 2-1, fig. 2-1,
or eqs. 2-3 and 2-4.)
D-2
By '-iT ~/./
-rr-
II
Checked
~'22 ";1
Date
Date
CN ~/ Area Product
of
hi ~es CN x area
I M ""
N I I
N N Omi2
C!
M 0%
..0 co co
~ 'rl .rl
E-< " ~
~
12 1q
. I
Totals =
1.q
Use CN
I 1z.. I
Storm {/l Storm 112 Storm 113
100 i?CJ 2~
6: g<; r f{1
S'. '2- '>
2.g~ 2-. t{ 0 (11
(210.VI-TR-55, Second Ed., June 1986)
\Vorksheet 3: Time of concentration (Tc) or travel time (Tt)
,~
\ ~s "" '" ",_ /_-=" -:.::
/"" :-,
i _...._-~:-/.~7~.:- ',-: . ...,; ,._
I
:\ " -;: r-:-
;~ ....:.,
By -:J-'C: _~
) i
Date
! "
C9 " ':~i. 2-... <~ ~'
Project
Location
Checked
Date
Circle one: Present Developed
Circle one: Tc Tt through subarea
NOTES: Space for as many as two segments per flow type can be used for each
worksheet.
Include a wap, schematic, or description of flow segments.
Sheet flow (Applicable to Tc only)
Segr.:ent ID
1.
Surface description (table 3-1)
........... .
2. Manning's roughness coeff., n (table 3-1) ..
3. Flow length, L (total L < 300 ft) .......... ft
4. Two-yr 24-hr rainfall, P2 .................. in
5.
Land
slope, s ..............................
0.007 (nL)0.8
P 0.5 0.4
2 s
ftlft
6.
T =
t
Compute Tt ......
hr
I + I
=0
Shallow concentrated flow
Segment ID
7. Surface .description (paved or unpaved) .....
.8. Flow length, L ... ........................... ft
9. Watercourse slope, s ....................... ftlft
10. Average velocity, V (figure 3-1) ...........
ft/s
L
11. Tt = 3600 V
Compute Tt ......
hr
1+1
=0
Channel flow
12.
Cross sectional flow area, a
.t............ .
Segment ID
ft2
13. Wetted perimeter, Pw ....................... ft
14.
Hydraulic radius,
a
r =-
Pw
Compute r .......
ft
15. Channel slope, s ........................... ftlft
16.
Hanning's roughness coeff., n ..............
1 49 2/3 1/2
V = . r s Compute V.......
n
ftls
17.
18. Flow length, L ............................. ft
19.
Tt =
L
3600 V
Compute Tt
... ...
hr
I + I
h:L~/1
20.
Watershed or subarea Tc or \ (add \ in steps 6, 11, and 19) .. ......
I
(210-VI-TR-S5, Second Ed., June 1986)
D-3
\Vorksheet 4: Graphical Peak Discharge method
Project
() ,
j/Q C:)V<<,
.-' .' r- '"
I
i
'\
!~'D\ ':~ C' ~~.,_/
, I
/ "'-..!l
(~
Location
.1\ \ ~ ---:,_ ~>\. . ~. (' ' Ie'
_1_ , .' ~;- iI" .\ ''.I -- '- "--
Circle one:
Present~~e;el~p~
'--- _:..---
1.
Data:
(, ~
Y;'J. 0 A
. " . . 'f.$. . . .
rn
,DI1.~J
0?-
0,2-'/
-IL
Drainage area
Runoff curve number .... eN =
Time of concentration .. Tc =
Rainfall distribution type =
Pond and swamp areas spread
throughout ~~atershed ...... =
By \ eli/_
! '
Checked
mi2 (acres/640)
(From worksheet 2)
hr (From worksheet 3)
0, lA, II, III)
Date
Da te
- ..-..
.9-.;::::.."
~ percent of A (--- acres or mi2 covered)
m -
2.
Frequency
. . . . t' . . . . . . . . . . . . . . . . . . . . . . . . . .
3.
Rainfall ,
P (24-hour) ...................
4. Initial abstraction, I .................
a
(Use C~ with table 4-1.)
5.
Compute I Ip
a
.................. .... ......
6.
Unit peak discharge, q .................
u
(Use T and I IP with exhibit 4- 117 )
c a
7.
Runoff, Q ......"."..."."."....."......""
(From worksheet 2).
8.
Pond
(Use
with
and swamp adjustment factor, F
p
percent pond and swamp area
tahle 4-2. Factor is 1.0 for
percent pond and swamp area.)
zero
9. Peak discharge, q ......................
p
(Where qp = quAmQFp)
D-4
Storm fll Storm fl2 Storm 113
yr ) ()() sr..J [<
58's t,2') I' 4.7
in ,
in I ,11g I
I ~,J~2qq I
I toq<; I
in I 2, g g I
UQJ
csm/in
,-;; r
I
,iJ@7--
~g,o
2- !-{ 0
I. u
I /17 r I
I ( (L,.. .;-,--1
I G,lsl
I f.Qj7 I
I ( u I
cfs I U/.10 I CZo ,It-! I ( (".L(! I
(210-VI-TR-55, Second Ed., June 1986)
. .
\Vorksheet 6a: Detention basin storage,
peak outflow discharge (qo) known
Project
Loca tion
Circle one:
Present Developed
By_
Date
Checked
Date
-II~ :~-i:ILjqf:_ J: - j~t=[-I-I~I:- -~1. - .:~- = - --- :~[IT[~:~t~ ~ ~-ltffi. thrrJ:ITHtt
- t' - -, /_-1: - -/- =1- = -- - _. :'- -c h '-1.' , = = iT_- - :OOFffilt' I I] ,: 'rn--t' :
-_:- ~1"..----~r=.- +1:::-i-1-:1- :::=--.+tLJ I IT: IJII
- - -I, - - - -,-I - , _. - T - -I- -T -t-- - r I TH~L '+ -t J :::
,'-, Ft - 'II ij/-t-/-I i -+-1 - - iii- -H+m- I I I I '.1.1
- ,- : - - t -/ ~ ' - - - : - -t1- -{ - -tl=~Ltt.E=_Lj-ti.Ji I- ~th; t.Lml , .w..
I I -1 ' - - -rr T - ,H-d. ++
- - j I I! I - -1= lr-+ _I- -i~=rn~- _TJ=-
I , - - - J t .TD-h- -j-- -LfTFir:
1- I I I I! I I I IT -1- - - - -1- = 1=,- fl i~+F 4t} h T :n
-1-1-1-/- - U-/1: t ! I' II' 111:1" : ~tf~- - :[+f: ~f':t --'-~~ffl' f-t f-Hj~r+m
'~.- . I 1'1 I -, 1':/. II I -I' '.j":. L/. r tj~t .-!~Llftf!:f:Fm.
- I' I 1 ,I - j J - , 'j i ' -1-r -I-rft-+-Lri-JM-'-'l-
I 1 i I 1'-1 LII I I -I,t - -. - :j- ~!:mJl.LH-H-i-J=trti I
'I II i I: I .' I 1 - - I,"j-r TthHlH-j--t+-H-h I :T~
CJ
co
r:l
.u
CIl
~
o
c:
o
oM
.u
r:l
>
CJ
r-l
:'-l
Detention basin storage
1. Da ta: _ 2
Drainage area ....... \n - Ic?ll.-;4..mi
Rainfall distribution
type (I, lA, II, III) rr-
2. Frequency......
yr I /00 1
3. Peak inflow dis- I 1
charge, qi .... cis 24.70
(From worksheet 4 or 5b)
01')C~t~(;~ ftZOIU.
. 4. Peak outflow d1s- I 1
z. 'fi2 <;~I2M. charge, qo .... cis 1~1q
E"Vt:~- OiZlC"iIIl.l'A1.,.. Cc.1.......\~,""t.l\A.').
5. Compute qo ......../0.(.,,';(1 1
qi
1/
J
Jj 2nd stage qo includes 1st stage qo.
6 . ~ s .........;...... /, '2-vS L
r qo
(Use -- with figure 6-1)
qi
7. Runoff, Q ...... in 17,221
(From worksheet 2)
I.
J
1
8. Runoff volume, I I
V r .......... ac-ft I ,(fa
(Vr .. QAm53.33)
9. Storage volume, I ,/ 1
Vs .......... ae-ft 0../..13-
V
(V .. V (2.))
s r V
r
10. Maximum stage, E I
max
(From plot)
(21O-VI.TR.55, Second Ed., June 1986)
D-7