HomeMy WebLinkAboutGrading Plans - 06/30/2016Pr
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Proposed Grade
≥6" from foundation tops
4" permeable pavers ≥2" Bedding Layer Crushed #8 Rock
≥12" Layer #2 Rock Sub-base
≥ 4" Layer #57 Rock Base
Undisturbed Soil
≥30-mil HDPE
Impervious
Membrane
Surfaces slope ≥¼” per foot towards street;
19" rise from curb to rear of addition.
Surfaces slope ≥¾” per foot towards line of
underdrain. Underdrains at property line on
S and mid-line on N.
Swale Detail
Proposed detached garage is constructed of
shipping containers and will not be
augmented with a traditional roof. It
therefore will not have gutters. The indicated
swale is intended to carry storm water away
from foundation and to provide opportunity
for storm water to percolate into soil.
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Drain 4" Underdrain
Grading Plan for 137 2nd St
Building Permit #B1602025
Owners:
Existing Impervious Area:
House: 722 sf drains to street
Garage: 360 sf drains to alley
New Impervious Area:
Garage: 640 sf drains to street
New Permeable Area:
Driveway: 440 sf tested to drain <32 mpi
Net Impervious Area: 541 sf – only existing
garage and north half of existing house
produce runoff
Existing grade to storm drain
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Existing grade to storm drain
Graph illustrates permeable bed exceeds rainfall
on south half of house, proposed garage, north
half of neighboring house and surface of swales
and permeable bed; accumulation <21".
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2,000
4,000
6,000
8,000
10,000
12,000
14,000
12:00 AM 3:00 AM 6:00 AM 9:00 AM 12:00 PM 3:00 PM 6:00 PM 9:00 PM 12:00 AM
ga
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hours of rainfall
100 year rainfall
influx percolation
Lot 12 Blk 9 Buckingham Place
Grading plan accepted 6/30/2016 DM
Testing and analysis of soil at proposed building site In cooperation with:
137 2nd St 133 2nd St
Fort Collins CO 80524 Fort Collins CO 80524
Owners: Owners:
Areas draining to permeable bed:
sf N‐SE‐W
231 8'3" x 28' swale between 133 2nd St & proposed garage
86 7'2" x 12' rear portion extends 1'1" to north
200 5' x 40' swale between 137 2nd St & proposed garage
105 21' x 5' transition area from E face of garage towards permeable bed
361 9'6" x 38' S portions of 137 2nd St (drains to permeable bed}
689 13' x 53' N portions of 133 2nd St (drains to S swale}
640 16' x 40' proposed garage
233 16'8" x 14' permeable bed (2 rectangular sections)
207 11'10" x 17'6"
7:00 AM 100 year rainfall drainage area permeable retention depth
1:58 PM Δ min per in 12:00 AM 2,752 440 25"
5:05 PM 8" 23.4 1:00 AM 2" 3,432 524 21 1/8"
7:54 PM 7" 24.1 2:00 AM 2 3/8" 4,075 1,048 22"
9:43 PM 5" 21.8 3:00 AM 2 1/2" 4,289 1,571 19 6/8"
8:43 AM 6:00 AM 3" 5,147 3,143 14 5/8"
9:23 AM 2 3/4" 14.5 12:00 PM 3 1/2" 6,005 6,286 0"
10:35 AM 3 3/8" 21.3 11:59 PM 4" 6,863 12,571 0"
12:35 PM 4 1/2" 26.7
3:20 PM 5 3/4" 28.7
5:10 PM 4" 27.5 annual 16" 27,281
8:37 PM 7" 29.6
31.4 average of last 3 measurements plus 10%
gallons
Percolation tested via "bucket test" ‐ 5 gallon bucket with bottom removed placed in hole dug in proposed
permeable bed area; top rim of bucket level with existing grade. Bucket filled to top at times indicated in table;
distance from bucket top to water level measured at end of each interval shown. Testing continued for 37 hour
period. The average of last 3 measurements plus 10% used to project accumulation in permeable bed.
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12:00 AM 3:00 AM 6:00 AM 9:00 AM 12:00 PM 3:00 PM 6:00 PM 9:00 PM 12:00 AM
ga
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hours of rainfall
100 year rainfall
influx percolation