[R.O. 2008 § 405.130; Ord. No. 6496, 9-13-2018]
In the City Council's consideration of applications for plat approval, the standards set forth in this Article shall be considered minimum requirements.
Minimum Escape Area Distance | |
|---|---|
Design Speed (MPH) | From Edge of Pavement to Breakpoint (feet) |
25 | 20 |
30 to 35 | 25 |
40 | 30 |
Table 1 — Runoff Coefficient Table (C) | |
|---|---|
Ground Cover | Runoff Coefficient (C) |
Pasture and unimproved areas | 15% |
Woods | 10% |
Lawns < 6% slope | 15% |
Lawns > 6% slope | 30% |
Graded/no vegetation < 6% slope | 50% |
Graded/no vegetation > 6% slope | 60% |
Gravel parking lot | 75% |
Gravel road | 80% |
Pavement, walks, buildings | 95% |
QWET = C * i * A |
Where: | ||
QWET | = | total stormwater runoff in cubic feet per second (cfs) |
C | = | runoff coefficient (dimensionless) |
i | = | 4.55 (rainfall intensity rate, inches per hour) |
A | = | drainage area in acres (ac) |
V = A * 1,800 (for Sediment Storage within a Trap) | ||
V = A * 3,600 (for Sediment Storage within a Basin) | ||
Where: | ||
V | = | total sediment storage volume in cubic feet (cf) |
A | = | drainage area in acres (ac) |
SVT = QWET + QDRY + V + 1 ft (Freeboard) |
Table 2 — Soil Stabilization Schedule | |
|---|---|
Soil Disturbance Activity or Condition | Required Stabilization Time |
Soil disturbance has ceased in areas greater than 2,000 square feet. | 14 days |
After construction of dikes, swales, diversions and other concentrated flow areas. | 5 days |
When slopes are steeper than 3 horizontal to 1 vertical. | 7 days |
When slopes are greater than 3% and longer than 150 feet. | 14 days |
Perimeter controls around soil stockpiles. | End of workday |
Stabilization or covering of inactive stockpiles. | 30 days |
When land disturbance is completed, permanent soil stabilization must be installed. | 30 days |
WQv | = | [(P)(Rv)(A)]/12 |
P | = | 1.14 inches of rainfall |
Where: | |||
WQv | = | Water quality volume (in acre-feet) | |
Rv | = | 0.05 + 0.009 (I) where I is percent impervious cover | |
A | = | Area in acres | |
Standard Detail Number | ROW Width | Pavement Width | Lane Width | Number of Drive Lanes | Utility Easement | Design Speed | |
|---|---|---|---|---|---|---|---|
Arterial | C203.64 | 84 | 63 | 12 | 5 | 10 | 40 |
Collector (urban) | C203.71 | 60 | 39 | 12 | 3 | 10 | 35 |
Collector (residential) | C203.84 | 60 | 38 | n/a | 2 | 10 | 25 |
Minor residential/ Local Access | C203.82 | 50 | 26 | n/a | 2 | 10 | 25* |
NOTES: | |
|---|---|
* | Can be varied with City Engineer's approval. Minimum posted speed shall be twenty-five (25) miles per hour. |
These requirements may be varied by other City ordinances. | |
Narrower pavement widths can be approved following Subsection (C) of this Section. | |
Parkway options can be provided with the City Engineer's approval. | |
Maximum Grade (percent) | Minimum Grade (percent) | Radius of Curve (center) | Corner Radii | |
|---|---|---|---|---|
Arterial | 5% | 2%* | 400 | 50 |
Collector | 8% | 2%* | 350 | 50 |
Residential collector | 10%** | 2%* | 200 | 37 |
Minor residential | 10% | 2%* | 150* | 37 |
Cul-de-sac | 10% | 2%* | 150* | 37 |
NOTES: | |
|---|---|
* | Can be varied with City Engineer's approval |
** | Some streets within large lot subdivisions may be higher per Section 405.300. |
These standards are minimum standards. | |