Chapter 5 - Publications, US Army Corps of Engineers

EM 1110-2-1701
31 Dec 1985
(2) Using the flow-duration data from Figure 5-18 and the head
versus discharge data from Figure 5-17, a head-duration curve can be
constructed (Figure 5-19). The shaded area defines the head range
where generation is produced. Figure 5-19 also shows the location of
the rated head and the design head. Design head in this case is
defined as the mid-point of the usable head range (see Section
5-5C(3)).
i. Derive Power-Duration Curve.
(1) Select 20 to 30 points on the flow-duration curve (Figure
5-19), and compute the power at each flow level using the water pwer
equation. Heads can be computed for each point as described in
Section 5-7f, or can be obtained from a previously derived head-
Rated _ [
Desian Head
(32.fft.)
Discharge
(34.0 fi)
o 20 40 60 80 100
PERCENTOFTIME EQUALLED OREXCEEDED
Figure 5-19. Head-duration curve showing minimum
head, maximum head, design head, and rated head
5-50