14.2 Storm Drainage II

Question 1

In gravity systems, water is always going to flow _________

Answer 1

downwards

Question 2

What’s soil boring?

Answer 2

Structural subsoil investigation

Question 3

What is the purpose of the water table?

Answer 3

Controls if you must dewater the site

Question 4

T/F Ground water is ALWAYS predictable

Answer 4

False.

Question 5

What are perforated pipes?

Answer 5

Tiny hole piping design that allows water to enter/exit at various points along the tube

Question 6

What consists in foundation drains/subsoil drains? (ex. basement)

Answer 6

• Perforated Pipes
• Open joint pipes
• utilize finer fill (back fill)

Question 7

What is the purpose of a solid interceptor/sediment basin?

Answer 7

To catch/retain solid particles in a mainline

Question 8

How does a solid interceptor/sediment basin work?

Answer 8

Water flows through inlet. Slows water down. Drops the sediment .Flows out through outlet

Question 9

What to look for in a site investigation?

Answer 9

Surface Contours, discharge locations, water table, flooding considerations, provision for future development.

Question 10

What is a surface contour?

Answer 10

The slope of the site.

Question 11

Where does the water in State College get discharged to?

Answer 11

Storm Drain -> Cheasepeake Bay

Question 12

Other Possible Discharge Locations:

Answer 12

Public Sewer, water ways, surface absorption, dry wells (French Drains).

Question 13

T/F You can build on top of the flood plane

Answer 13

TRUE. Must calculate 1/2” off flood plane.

Question 14

How is storm water managed?

Answer 14

GPM before > GPM after. Run off cannot exceed than before

Question 15

What design considerations should you consider at an intersection?

Answer 15

Place drains above intersection on UPHILL side.

Question 16

What design considerations should you consider for a series inlet?

Answer 16

Bypass 25% of water. Place 300’ max apart. Locate inlets at low points. place manholes (change in directions). pipe must remain STRAIGHT.

Question 17

What’s a drainage inlet?

Answer 17

Inlet that’s free from debris/sediment. Dry.

Question 18

What’s a catch basin?

Answer 18

Catches debris, requires maintenance. Outlet is raised higher.

Question 19

What’s a manhole?

Answer 19

NOT an inlet. Used for change in direction or elevation.

Question 20

What’s a drop manhole?

Answer 20

Manhole that can be emptied so that maintenance worker can go down in.

Question 21

T/F a manhole is a type of inlet.

Answer 21

FALSE.

Question 22

What materials are used for manholes?

Answer 22

Brick and Pre-cast concrete

Question 23

What does the term “invert” mean on a manhole drawing?

Answer 23

The channel at the bottom of a manhole that directs water to flow from the inlet to the outlet.