Deck 11: Runoff Calculations

Question 1

The Rational Method is intended to compute the entire hydrograph of a rainfall event.

Answer 1

False

Question 2

The NRCS Method results in a more ____________________ depiction of the runoff process than does the Rational Method.

Answer 2

realistic

Question 3

There is no way to account for infiltration and evapotranspiration in the Rational Method.

Answer 3

False

Question 4

The usual basin size used in the Rational Method is less than ____.

A)5 acres
C)30 acres
B)15 acres
D)100 acres

Question 5

The Modified Rational Method is intended as a simple approximation for small detention basins with ___________________ outlet structures.

Question 6

The Rational Method is a method to compute ____.

A)overland flow
C)runoff
B)drainage area
D)rainfall

Question 7

What method yields a hydrograph for use in detention basin design?

A)Rational Method
C)Manning's equation
B)Modified Rational Method
D)NRCS method

Question 8

The design storm frequency usually depends on the size of the ___________________ to be designed.

Question 9

At the core of the NRCS Method is the dimensionless unit hydrograph.

Question 10

To compute rainfall losses, the NRCS method uses ____.

A)the runoff coefficient
B)the concept of initial losses based on cover characteristics
C)the 100-year storm
D)the 2-year peak runoff

Question 11

When using the Rational Method, the drainage basin ____________________ characteristics should be homogeneous.

Question 12

The ____________________ Method is a procedure for computing a synthetic runoff hydrograph based on empirically determined factors developed by the Soil Conservation Service (SCS).

Question 13

Peak runoff is computed by ____.

A) $T _ { t } = \frac { 0.007 ( n L ) ^ { 0.8 } } { \left( P _ { 2 } \right) ^ { 0.5 _ { S } 0.4 } }$
B) $Q = \frac { \left( P - I _ { a } \right) ^ { 2 } } { \left( P - I _ { a } \right) + S }$
C) $q _ { p } = q _ { u } A _ { m } Q$
D) $S = \frac { 1000 } { C N } - 10$

Question 14

The primary application of the Rational Method is in estimating peak runoff for small drainage basins.

Question 15

Most field conditions yield an n-value between 0.40 and 0.60.