§ 32-118. Drainage improvements.

(a)

Drainage ditches. Side slopes one on three or flatter, min. grade 0.001 (0.1 percent), greater for small ditches. Concrete lining will be required if a utility easement is used. Alleys will not serve as a drainage ditch.

(b)

Inlets. Curb inlets, other types as specifically approved only.

(c)

Pipe. Reinforced concrete, other types as specifically approved only. Backfill water consolidated.

(d)

Culvert. Reinforced concrete with appropriate headwalls or end sections.

(e)

Design.

(1)

Major drainage structures designed by rational method for 25-year storm; minor drainage structures designed for five-year storm.

(2)

Storm drainage design (areas less than 200 acres):

I =   B 
     E

(T+D)

i = intensity of rainfall, in./hr.

T = time of concentration, minutes

D = 8.7

For five-year frequency:

B = 78.0

E = 0.789

For 25-year frequency:

B = 91.0

E = 0.757

(f)

Lot grading. One-half percent slope toward designated and maintained drainageway, all building sites such that lowest occupied floor is above 100-year flood level.

(g)

Drainage plan. The town is vitally concerned that adequate drainage is obtained. If for any reason, it is not feasible to meet the above minimum requirements, the engineer for the developer will prepare a drainage plan acceptable to the town engineer for consideration by the town council.

(Ord. No. 1990-1, app. § 3, 4-16-1991)