2005-9437 I •
•
° Civil Engineering
• Land Planning
• Structural
• Surveying
`Tiny 7, 2005
1 OF 2j
FIYDROLOGy STUDY
FOR
RSTIE LANE IMpROVE
TENTS
DESCRIPTION:
POST BMP DRAINAGE
IMPROVEMENTS TREATMENT FOR
COLONY OLIVENHA ALONG KIRSTIE LANE
A. P.N. 264-101-16, 35, 38, 42, 64, &66
PERMITTER: QApF � �
DAVID SCHIBLER �r o O IO<
3533 F ORT i� O �'
OLIV IINA RANCH ROAD 0 3970
ENHAIN, CA 92024
619-980-0243
DO
LAS E. L AN
R. C.E. 39726
EXPIRES DATE
12-31-05
Office: 1635 S. Rancho Santa Fe
Mailing; 132 N. Road, #204 • San Marcos, CA 92078
El Camino Real, PMg_
Phone 760- N • Encinitas, CA 9X024
510-3152 • Fax 760-510-3153
Email; dlogan@dlogan.connectnet.com
85TH PERCENTILE
Modified Rational Method FLOW AND VOLUME DETERMINATION
- Effective for Watersheds < 1,0 mis
Note:Only Enter Values in Boxes_spreadsheet Will Calculate Remaining Values
Project Name
Work Order Kirstie Lane
Jurisdiction SChibler-Kirstie Lane
City of Encinitas
BMP Location
Water tributary to Kirstie Lane
85th Percentile Rainfall
(from County Isopluvial 0'70 inches
Map)
Developed Drainage
Natural Drainage ge Area - 5.60
9 Area= acres
To__tal Drainage Area to SMIS= 9'50 acres
15.1 acres
Dev. Area Percent Impervious
Overall Percent Impervious 10 %
pervious
Dev. 4 °0
Area Runoff Coefficient=
Nat. Area Runoff Coefficient= 0.41
Runoff Coefficient= 0.35
0.37
Time of Concentration =
(from Drainage Study) 10.0 minutes
R____ATIONAL METHOD RESULTS
Q °CIA where
Q ° 85th Percentile Peak Flow(cfs)
C = Runoff Coefficient
I - Rainfall Intensity(0.2 inch/hour per RWQCB
9 Area (acres mandate
V= CPA where V= ) )
85th Percentile Runoff Volume (acre-feet)
C= Runoff Coefficient
P_ 85th Percentile Rainfall(inches)
A= Drainage
Using Develo ed Area (acres
Area Only:
nly:
C=
I= 0.41
P= 0.2 inch/hour
A= 0.70 inches
acres
V= 0.46 cfs
0.13 acre-feet
Grassy Swale Design Spreadsheet
Given:
Design flow
Residence time(req) 0.23 cfs S
P 9 Minutes Qpeak_ Height
— eak flow rate,cis
Trapezoid Channel Design p d
9 Par 1
y 0.25 feet SSi
t F
w 6 feet SS2
SS1:SS2 4 feet
A 4 ft/ft
1.25 sq ft W
Find Diagram of Swale Variables Used in Spreadsheet
Find Qmax of channel:
Q= (1.49/n)*A*R"(2/3)*s^5 V Find elcoity in channel
s 0.2 Therefore:
r 0.01 ft/ft(long.Slope) V=
0.217391 ft 0.184 fps
Q= 0.336688 cfs
Required Length of Channel:
L=vt
Therefore:
L 99.36
USE: 2 SWALES at L=100
THE NATURAL DISCHARGE/LOW PAINT IN KIRSTIE
THE INTERSECTION WITH /LOW POINT
RANCH ROAD AND BOTH PORTIONS
OF THE DISCHARGE POINT) LANE IS LOCATED ROUGHLY 380 L.F.
TO TREAT ALL STORMWATER TRIBUTARY TO THE DISCHARGE POINT TO THE SOUTH FROM
WILL THE CONVEY FLOW TO THE POINT OF DISCHARGE.
UTILIZED; OF KIRSTIE LANE(NORTH AND SOUTH.
ONE FLOWING IN A NORTHERLY DIRECTION,
TVER TREATMENT SWALES WILL BE
ONE IN A SOUTHERLY DIRECTION,