HomeMy WebLinkAbout1985-06-17 Board of Survey Minutes Board of Survey Meeting of June 17, 1985 Page 1
A meeting of the Board of Survey convened in Room 16, Municipal
Building at 7: 50 P.M. Present were Chairman Barker, Secretary Hampson,
Board Members Polychrones, Criffin and Boucher, Supt. A.V. Fletcher, P.E.
and Asst. Supt's. McIntire and Redford.
The Board discussed the Li)ah Lane Phase III (Sanborn Village)
development.
Present were Jack Rivers, developer, 0. Bradley Latham, Attorney,
and Bill Jones, Engineer for Dana Perkins & Associates.
Asst. Supt. Redford stated after speaking with the Conservation
Commission, and on my recommendation, I recommend that the Board approve
the subdivision subject to the conditions outlined on my June 14th memo.
All of these conditions, except for Item #17 have been addressed either by
letter from the attorney or letter from their Engineer.
Bill Jones presented the Hoard with the new set of plans.
Asst. Supt. Redford stated the applicant has removed the
highway-type guardrail and is proposing a pipe rail protection on top of
the retaining wall.
Both Mr. Criffin and Mr. Hampson were concerned for the safety of
children in this area with regard to this retaining wall and rail. Mr.
Hampson felt the developer should check into OSHA's regulations regarding
this type of rail and retaining wall.
Regarding Item #17 (proposed 2' x 3' box culvert) Mr. Redford
stated I would recommend a straight 2' x 3' box culvert through with no
obstruction. He added, I would assume Conservation Commission may have a
differing point of view and we may come back with an inlet control
structure.
Mr. Jones stated we have sized the control structure as shown on
the plan to replicate the 18" pipe.
Board of Survey Meeting of June 17, 1985 Page 2
Mr. Redford stated any control structure needs to be maintained.
If we had one less structure it would be a savings to the Town. With a
free-flowing structure, you won't have a problem.
Mr. Griffin asked is there grating over this?
Mr. Jones replied yes.
Mr. Griffin stated you are asking us to uphold a principle
regarding the original structure. What is the disadvantage in your
estimation of voting for the control structure?
Mr. Redford replied in realistic terms, probably none.
Mr. Griffin moved, and it was seconded, to accept Sanborn Village
Phase III with the inclusion of Item #17 of Mr. Redford's June 14 memo and
subject to all items listed in same memo (attached).
Mr. Hampson amended the motion that as part of the motion, the
traffic rail on top of the walls on both sides of Sanborn Lane have a
closer rail space for protection of toddlers.
The main motion as amended was voted 4: 1 (Mr. Boucher opposed).
Chairman Barker stated I view the continuing need to approve
subdivisions with items pending and cause members of the Board and
Department additional work, as not in the best interests of the Town. This
leaves us open to problems down the road. I would feel more comfortable
if these could come in in a more timely fashion.
The meeting adjourned at 8:30 P.M.
Respectfully submitted,
/ ret, y
MEMORANDUM
To: A.V. Fletcher, P.E.
' From: W.A. Redford
Date: June 14, 1985
Subject: Sanborn Village - Phase III Subdivision Definitive Filing
The Department, Conservation Commission, and the applicant met to
resolve the issues remaining on this filing. After discussion (and in
consideration of prompt action limiting the need for further time delays)
the applicant has agreed to modify the plans as required and drop all
waiver requests (except at the property corner of Lot 18 and the Dutcher
property).
In view of these (and the fact that the roadway alignment
modification (item no. 6) required the shifting of six lot lines) causing
delays in modifying the plans for resubmission, I said that I would
recommend approval (but not promising that the Board would act favorably)
without the plans being "in hand".
I recommend the following Board action:
1. The Board APPROVE the subdivision entitled "Definitive Plan Phase III
Sanborn Village dated April 9, 1985, submission subject to the following
conditions:
a) The submission of a satisfactory Covenant Agreement by
July 17, 1985;
b) The submission of a satisfactory Conveyance of Easements &
Utilities by July 17, 1985;
c) The submission of two (2) modified sets of mylar plans by
July 17, 1985;
d) The submission of satisfactory Center Line and Street line
coordinates by July 17, 1985;
e) The restriction, within the Covenant Agreement that restrict
the placement of underground storage tanks on any
lot contained in this subdivision.
f) Complicance with the Board of Public Works 2 for 1 I/I
elimination policy.
g) Submission of the following modifications/additions to the
plans, acceptable to the Department of Public
'
Works:
1. The proposed sidewalk layout (station 30+0 to 12+0) must conform
to the required roadway cross-section.
2. The proposed side slope must conform to the maximum (3 to 1).
3. The satisfactory layout of Sanborn and utility layouts extending
to the end of Lot 1.
4. The revision of the 'old' Sanborn Lane revision.
S. The sewer main layout revision on Verde Circle.
6. Acceptable minimum cellar floor elevations shown on the plans
(sheets 1 & 2).
7. Water main revision to have• S' of cover.
B. All catchbasins will have 3.0' sumps.
9. Relocation of the catchbasin locations at the intersection of
Verde & Lilah.
10. The detail of the culvert crossing of the sewer must be provided.
11. The design specifications of the Retaining Wall must be provided.
12. Additional bounds provided (lot 1, 6, and lot 7).
13. The sight easements provided be wider.
14. The proposed water main and hydrant layout must be revised to
accomodate the following;
a. add a line gate at the end of the existing line;
b. shift the location (into the roadway area) near Lots
S-1 & S-2.
C. add a hydrant on Lilah Lane (near Lot 4?); and
' d. revise the hydrant located near Lots @-1 & S-2.
16. The sewer connection detail must show 1/4" per foot slops.
16. The chimney connection detail must be revised to Reading's
requirements.
17. The modification of the proposed 2'X 3' box culvert being limited
to the width under of the roadway section without any inlet or
outlet control restrictions being constructed.
RECEIVED
BOARD OF PUBLIC WORKS
6 0/ SUAJ it /y7 / 9 &y
LATHAM AND LATHAM, P.C.
649 MAIN STREET
READING, MASSACHUSETTS 01867 TOWN OF READING
KENNETH C. LATHAM AREA CODE 617
O. BRADLEY LATHAM TELEIHONEI 944-0805
DAVID J. LATHAM
WILLIAM C' WAGNER
SANDOR RABKIN
KATHLEEN M. MITCHELL June 14, 1985
William Redford, Assistant Superintendent
Board of Public Works
Town Hall
Reading, Massachusetts 01867
Re: Phase III Sanborn Village, Reading, Massachusetts; Rivers Development Corp. -
Applicant
Dear Mr. Redford:
' We wish to advise that it is our opinion that our client, Rivers Development
Corp. is not precluded by law from laying out a subdivision standard roadway as
shown on the definitive plan filed with your office, provided requisite governmental
approvals are obtained.
With reference to the Butcher property situated on the northerly side of
existing Sanborn Lane, we wish to advise that access to his property would not be
legally precluded by the construction of the subdivision standard roadway. The
retaining wall on the northerly side could be designed such that Mr. Butcher
could construct a driveway onto his property if he wished to construct one, provided he
obtains all governmental approvals and permits to do so including wetland permits
and curb-cut permits.
With reference to the Butcher property, it is evidence that a good portion of
that property is located within a zoning flood plain district, the proposed
acquifer protection district and is subject to the jurisdiction of the Reading
Conservation Commission. Therefore, there is no way that we could in any way
suggest that the Butcher property is developable from a practical view point.
Sincerely,
LATHAM AND LATHAM, P.C.
F R1
DANA F.
i PERKINS & ASSOC., INC
CIM-14" Ca9i"em F30ARDOF/PU/CSC l�ilCi�all-if
5
OF READING
June 13, 1985
Mr. William Redford
Town of Reading
Board of Public Works
Municipal Building
16 Lowell Street
Reading, Massachusetts 01867
Re: Sanborn Village - Phase III
Reading, Massachusetts
Dear Mr. Redford:
In reponse to concerns expressed by the Town of Reading Board of Public Works
and Board of Survey during and subsequent to the public hearing for the
above-referended subdivision, as well as concerns expressed by the Town of
' Reading Conservation Commission, the applicant (Rivera Development
Corporation) has decided to revise the plans for the proposed project in the
area between Station 10+0 and Station 12+0, Sanborn Lane, in the following
manner:
1. The proposed concrete retaining wall on the southerly side of Sanborn
Lane will be moved so that it is positioned just outside of the
right-of-way. By moving this wall approximately three to four feet, it
is possible to construct the sidewalk at the back of the layout (five
feet from the travelled way) and provide for a five foot tree lawn as
shown in the Town of Reading's normal roadway cross section.
2. On the northern side of the roadway a concrete retaining wall will be
constructed approximately 11 feet distant from the northerly curb line of
Sanborn Lane. This retaining wall will provide for positioning the
sidewalk five feet from the curb line as shown 1n the Town of Reading's
normal roadway cross section and will eliminate the necessity for a 2:1
slope,
3. In making these modifications, however, it is necessary to obtain a
waiver on the tree lawn width in the area of the southwest corner of Lot
18 and the southeast comer of the Butcher property. This waiver is
necessary because the concrete retaining wall in this vicinity must be
constructed entirely within Sanborn Lane or on property owned by Rivers
Civil • Environmental • Land Surveys
125 Main Street, Box 506, Reading, Mass. 01867 — 944-3060
43 Lakeview Avenue, Box 1322, Lowell, Mase. 01852 — 452-9871
Mr. William Redford -2- June 13, 1985
' Development Corporation. It is our feeling that the tree lawn in this
area will have to be constructed at a width of approximately two feet
to two feet six inches in order to accommodate the five foot sidewalk and
provide for constructing a retaining wall at the rear of the sidewalk
within the 50 foot layout. Every effort has been made to minimize the
area in which the waiver 1s required which as presently (providing for
smooth transitions) encompasses an area of approximately fifty feet on
one side of the roadway only.
4. In addition to the above revisions, it is presently proposed to construct
the retaining wall with a pipe rail fence on top rather than utilizing
standard steel beam highway guardrail.
By changing the proposed drawings in this manner, it is our feeling that we
have adequately addressed comments #2, #3, #14 and #23 as contained in the
Town of Reading Board of Public Works Engineering Division review of the
proposed subdivision. As stated, we have eliminated the nonconformance with
the required roadway cross section except for an area approximately fifty feet
in lenght, and totally eliminated the necessity for any 2:1 side slope. By
eliminating the guardrail and constructing the retaining wall as shown on the
revised drawings, it is our feeling that we have not adversely impacted access
to the abutting property owned by Butcher.
In addition to the above revisions, our firm is also in the process of
revising the drawings for the subdivision and preparing information requested
by the Town of Reading Board of Public Works Engineering Division as follows:
Comments #4 and #5
Upon completion of all of the revisions to the drawings, traverse,
calculations, roadway coordinates, lot traverses, roadway traverses, and
property coordinates and a complete plot of the subdivision will be submitted
to the Town of Reading Board of Public Works Engineering Division. This
information is in the process of being revised due to shifting of lot lines
required as outlined below.
Coament #6
After consulting with the Town of Reading Board of Survey Engineering
Division, the plans are being revised to extend the 50 foot layout of Sanborn
Lane to the end of the rounding curve of Lilah Lane. From that point the
layout assumes a transition eventually ending in a 40+ foot layout at the
corner of Lots 1 and A-2. This change has necessitated a shifting of lot
lines for Lots 1 thru 6 and 15 thru 17 requiring substantial revision to all
of the plana of the subdivision.
Comment #7
The proposed connection to Old Sanborn Lane has been revised to reflect a
' narrower driveway type opening.
Mr. William Redford -3- June 13, 1985
' Comment #8
The sewer main layout on Verde Circle has been revised as requested.
Comment #9
Latham 8 Latham has provided documentation of existing easement rights to the
Town of Reading Board of Public Works Engineering Division.
Comment #10
The existing overhead wire service referenced in the subdivision review is a
previous private service on the property and has since been disconnected.
During construction of the subdivision, the remaining poles will be removed.
Comment #11
Minimum cellar floor elevations have been added to the plans as requested by
the Board of Survey.
Comment #12
Reference is made to the attached letter regarding the Rational Method
calculations as well as the hydraulic calculations contained in the original
' report which indicate that although stormwater drainage from Sanborn Lane will
discharge to the south of Sanborn Lane, there will be no adverse impact on
storm damage control or flood prevention in this area.
Comment #13
As discussed with the Town of Reading Board of Survey Engineering Division,
the water main will be revised to reflect five feet of cover in general.
However, the water main will dip in the area where it crosses proposed
drainage lines to provide for adequate clearance.
Comment #15
All catch basins will have the required three foot sump as shown on the
details contained in the original drawings. Catch basin connotations on the
roadway profiles have been revised to show three foot sumps.
Comment #16
The catch basins located at the intersection of Verde Circle and Lilah Lane
have been revised according to the comments of the Engineering Division.
Comment #17
' It is the contention of the applicant as well as our firm that the
construction of stilling basins on the property do properly address the impact
of the additional stormwater runoff. It is our feeling that the major concern
with this runoff is that it enter the flood plain of the Ipswich River in a
Mr. William Redford -4- June 13, 1985
nonerosive manner. As stated in the original report submitted with the
subdivision, our firm believes that the flood plain and wetlands abutting the
Ipswich River are more than capable of handling the additional stormwater
runoff from the project with no adverse impact. Therefore, our firm has
proposed stilling basins within the subdivision in order to insure that the
transition in flow between the subdivision and the wetlands/flood plain occurs
with no adverse impact.
Comment #18
A detail of the culvert crossing of the sewer is being provided on the revised
drawings.
Comment #19
The design specifications of the retaining wall have been added to the
drawings.
Comment #20
As discussed with the Engineering Division, the excavations proposed along the
retaining wall result in only a minimal difference between the depth and
extent of retaining wall required if no excavations were proposed. As the
Board is aware, the applicant must meet stringent requirements of the Town of
Reading Conservation Commission regarding filling in wetlands within the area
' of the proposed roadway crossing. In order to meet these requirements, the
applicant believes that the excavations along the retaining wall are required
and that they do not create any additional safety concerns.
Comment #21
Additional proposed stone bounds have been added to the plan in the areas of
Lot 1, 6 and 7.
Comment #22
In accordance with discussions with the Engineering Division, the site
distance easements provided have been widened.
Comment #24
The water main and hydrant layout has been revised according to the comments
of the Engineering Division.
Comments #25 and #26
The sewer connection details have been revised to show 1/4-inch per foot slope
and the chimney connection detail has been revised to the Town of Reading's
standard requirements.
Mr. William Redford -5- June 13, 1985
Comment #27
The original plan submitted proposed control of oil and gas pollution
discharged by the use of catch basin hoods within each and every catch basin.
This proposed system will be adequate to control contamination of oil and gas
from the subdivision. As discussed with the Engineering Division the
applicant has agreed to limit underground storage tanks in the subdivision's
covenant agreement.
Comment #28
The applicant is aware that the subdivision will require compliance with the
Board of Public Works two for one I/I policy.
Comment #29
Information regarding the capacities of the Collins Avenue sewage pumping
station has been submitted to the Board of Public Works at the public hearing
and we belive the Superintendent is satisfied with this information.
As discussed above, the plans for the subdivision are being revised in
accordance with the Department's comments and as outlined. We apologize to
the Board for the delay in making the revisions to the final plans for the
development. However, the comments of the Engineering Division resulted in
the relocation of nine lot lines and the revision of two roadways. The
' incorporation of a retaining wall on the north side of the Sanborn Lane
culvert crossing and shifting of the sidewalks to conform with the typical
cross section have also resulted in substantial revisions required to the
plans. Our firm is making every effort to complete the revisions to the plans
as soon as possible, however, since the revisions requested are more than
minor, we would appreciate the Board's consideration in this regard.
Very truly yours,
DANA F. PERKINSINC.
William A.
Project Manager
WAJ/hmk
cc: Mr. John R. Rivert
Mr. 0. Bradley Latham
DANA F. rPERKINS & ASSOC., INC. ,
' e-walling C�agiaeem RMD (IF FUBUC WORKS
SU'j f- /v/ / r 9-5,
June 12, 1985 //:30 AM e'j /C
TOViN OF READING
Mr. William Redford
Town of Reading
Board of Public Works
Municipal Building
16 Lowell Street
Reading, Massachusetts 01867
Re: Sanborn Village - Phase III
Reading, Massachusetts
Dear Mr. Redford:
As requested by you, our firm has completed calculations of the peak runoff
from the proposed Phase III, Sanborn Village Subdivision in Reading,
Massachusetts utilizing the Rational Method. The calculations of both the
existing and site developed runoff are attached to this correspondence. You
will please note that the areas referenced as 6, 7 and 8 represent those
portions of the overall watershed which will be altered by the development.
Area 6 is that area which is presently tributary to the wetlands upstream of
Sanborn Lane. Areas 7 and 8 are those portions of the site directly tributary
to the Ipswich River (area 7 being located on the easterly side and area B
being located on the westerly side of the site) .
The following is a summary of the impact of site development on the peak rates
of surface runoff at the various points of discharge for ten and one hundred
year storms based on the rational method calculations.
Existing Developed Existing Developed
Ten Ten One Hundred One Hundred
Year Storm Year Storm Year Storm Year Storm
Point B (CFS) (CFS) (CFS) (CFS)
Area 6 - Point "A" 9.5 12.2 13.9 17.1
(Sanborn Lane)
Area 7 - Point "B" 6.8 17.1 9.8 23.9
(North Side)
Area 8 - Point "C" 12.2 13.6 17.1 19.1
(North Side)
Civil • Environmental • Land Surveys
125 Main Street, Box 506, Reading, Mass. 01867 - 944-3060
43 Lakeview Avenue, Box 1322, Lowell, Mass. 01852 - 452-9871
Mr. William Redford -2- June 12, 1985
A comparison of the above numbers indicate (as outlined in the original report)
that there will be increases in the peak runoff from areas 6, 7 and 8 when the site
is developed according to the plans presented to the Town of Reading Board of
Survey. It should be noted in the case of area 6, that although the calculations
indicate a 2.7± CPS increase in peak runoff for the 10 year storm and a 3.2± CES
increase in the peak rate of runoff for the 100 year storm, this increase is of
extremely short duration. An examination of the figures for area 6 indicates that
due to drainage routing in the developed subdivision, the drainage area tributary
to the wetlands upstream of Sanborn Lane will be reduced from 6.8 acres existing to
4.35 acres developed. This decrease in drainage area, however, is accompanied with
an increase in the composite runoff coefficient. When these two factors are taken
together the total runoff volume tributary to the wetlands south of Sanborn Lane
will exhibit a 4% decrease (site developed versus existing) . The increase in peak
runoff tributary to this wetlands is primarily due to the decrease in time of
concentration by the creation of lawns and impervious surface. Since the product
of the composite runoff coefficient in the area in the site developed condition
decreases, the increassed runoff will occur only during that time period which is
the difference between the existing time of concentration and the site developed
time of concentration. Therefore, the increase in peak runoff from area 6 is only
distributed over a very short 12 minute period. Since this runoff enters an
extremely large (12± acre) storage basin, the immediate increase in peak runoff
will be totally mitigated and, in fact, the development of the site as proposed
will be beneficial to the wetland south of Sanborn Lane (in terms of flood control
and storm damage prevention) due to the 4% decrease in runoff volume.
' The calculations also show an increase in the combined runoff from area 7 and 8
(representing the site developed runoff directly tributary to the Ipswich River) or
15.9± CPS for the 10 year storm and 31± CES for the 100 year storm. This
calculation (and the calculations for area 6 above) show fairly consistent results
with the values obtained by the SCS method as shown on page 23 of the original
report.
The following is a summary of the impact of site development on the peak rates of
surface runoff at the various points of discharge for ten and one hundred year
storms as calculated by the SCS Method and shown on page 23 of the original report.
Existing Developed Existing Developed
Ten Ten One Hundred One Hundred
Year Storm Year Storm Year Storm Year Storm
Point # (CES) (CPS) (CPS) (CES)
Area 6 - Point "A" 8.1 11.5 21.3 25.1
(Sanborn Lane)
Area 7 - Point "B" 5.8 16.4 15.6 37.2
(North Side - east)
Area 8 - Point "C" 7.8 13.1 20.8 30.2
(North Side - west)
Mr. William Redford -3- June 12, 1985
As outlined in pages 24 thru 26 of the original report, it is the opinion of our
firm that the Ipswich River and abutting wetlands are more than capable of
absorbing this increase in peak runoff from the site with no adverse impact on
storm damage or flood control prevention in the Area.
4.
V
aRA Assoc. , Inc.
D age, E.
DEM/hmk cC
cc: Mr. John R. Rivers
Mr. 0. Bradley Latham
i
PHASE III - SANBORN VILLAGE
READING, MASSACHUSETTS
OVERALL SITE RUNOFF CALCULATIONS
Rational Method
AREA 6 - Existing
1. Drainage Area: The existing drainage area = 6.82 acres
2. Composite Runoff Coefficient: The composite runoff coefficient is as follows:
Surface Type Area "C" CA
Wooded/Meadow 6. 10 0.30 1.83
Lawns 0.30 0.35 0.11
Pavement 0.40 0.95 0.38
CA = 2.32
"C" - 2.32/6.80 - 0.34
3. Time of Concentration: As shown on page A-12 of the original report, the
existing time of concentration for Area 6 is 12 minutes.
' 4. Existing Peak Runoff:
Q100 = Cx 1100 x
- 0.34 x 6.0 x 6.8
- 13.92CFS
Q10 - Cx 110 x
= 0.34 x 4.1 x 6.8
= 9.52CFS
AREA 7 - Existing
1. Drainage Area: The existing drainage area - 4.82 acres
2. Composite Runoff Coefficient: The composite runoff coefficient is as follows:
Surface Type Area "C" CA
Wooded/Meadow 4.80 0.30 1.44
CA = 1.44
' "C" - 1.44/4.80 - 0.30
3. Time of Concentration: As shown on page A-13 of the original report, the
existing time of concentration for Area 7 is 8 minutes.
I* Existing Peak Runoff:
Q100 C x 1100 x A
= 0.30 x 6.80 x 4.80
9.8±CFS
Q10 = C x 110 x A
= 0.30 x 4.75 x 4.80
= 6.8±CFS
AREA 8 - Existing
1. Drainage Area: The existing drainage area = 6.10± acres
2. Composite Runoff Coefficient: The composite runoff coefficient is as follows:
Surface Type Area "C" CA
Wooded/Meadow 6. 10 0.30 1.83
CA = 1.83
"C" - 1.83/6.10 - 0.30
3. Time of Concentration: As shown on page A-14 of the original report, the
existing time of concentration for Area 8 is 7.5 minutes.
4. Existing Peak Runoff:
Q100 C x 1100 x A
- 0.30 x 6.90 x 6.10
- 12.6±CFS
Q10 - Cx 110 x
- 0.30 x 4.85 x 6.10
= 8.9±CFS
AREA 6 - Developed
1. Drainage Area: The site developed drainage area = 4.35± acres
2. Composite Runoff Coefficient: The composite runoff coefficient is as follows:
Surface Type Area "C" CA
Wooded/Meadow 0.65 0.30 0.19
Lawns 2.50 0.35 0.87
Pavement 1.20 0.95 1.14
CA = 2.20
"C" - 2.20/4.35 - 0.51
' 3. Time of Concentration: As shown on page B-3 of the original report, the
developed time of concentration for Area 6 Dev. is the minimum time of
concentration (5 minutes).
4. Existing Peak Runoff:
Q100 - Cx 1100 x
- 0.51 x 7.7 x 4.35
- 17.1±CFS
Q10 - Cx 110 x
- 0.51 x 5.50 x 4.35
- 12.2±CFS
AREA 7 - Developed
1. Drainage Area: The site developed drainage area - 7.05± acres
2. Composite Runoff Coefficient: The composite runoff coefficient is as follows:
Surface Type Area "C" CA
' Wooded/Meadow 1.80 0.30 0.54
Lawns 4.00 0.35 1.40
Pavement 1.25 0.95 1.19
CA - 3.13
"C" - 3.13/7.05 - 0.44
3. Time of Concentration: As shown on page B-5 of the original report, the
developed time of concentration for Area 7 Developed is the minimum time of
concentration (5 minutes).
4. Existing Peak Runoff:
Q100 - Cx 1100 x
- 0.44 x 7.7 x 7.05
- 23.9±CFS
Q10 - Cx 110 xA
- 0.44 x 5.5 x 7.05
- 17.1±CFS
1
AREA 8 - Developed
1. Drainage Area: The site developed drainage area = 5.90± acres
2. Composite Runoff Coefficient: The composite runoff coefficient is as follows:
Surface Type Area "C" CA
Wooded/Meadow 2.35 0.30 0.70
Lawns 2.70 0.35 0.94
Pavement 0.85 0.95 0.81
CA - 2.45
"C" - 2.45/5.90 - 0.42
3. Time of Concentration: As shown on page B-6 of the original report, the
developed time of concentration for Area 8 Developed is the minimum time of
concentration (5 minutes).
4. Existing Peak Runoff:
Q100 = Cx 1100 x
- 0.42 x 7.7 x 5.90
- 19.1±CFS
' Q10 - Cx 110 x
- 0.42 x 5.5 x 5.90
- 13.6±CFS