13831

5 25 2 :

3 : 4 : 5 6

7

. . . . . . 8 9

10

11 T . 25 100 4 . .

T: N:

12 . : 2 5 : 2 25 : 10 100 1000 10000 13 : : : : : :

14 normal ( ) lognormal gamma pearson III III logpearson gumbel pareto logistic kappa wakeby 15

16 (X) (x) . .

17

18

19 Positively skewedNegatively skewed

Skewness20 . :

21

22 1Z

23

24

25 rankdata12n

26 27

.

.

2829

Normal MethodFind Q which has a return interval of TDetermine Q and Sq from {Qs} Determine KT from table or equationSolve for Q = Q+ KT*Sq Determine the return interval for a discharge of QDetermine Q and Sq from {Qs}Solve for KT = {Q -Q } / SqSolve for T by interpolating from table or equation:

30LogNormal MethodFind Q which has a return interval of TDetermine Y and SY from {Qs} using either Y = log Q or Y = lnQDetermine KT from table or equation Solve for Y = Y+ KT*SYSolve for Q using Q = 10Yor eYSolve for Q using Q = 10Yor eY Determine the return interval for a discharge of QDetermine Y and SY from {Qs} using either Y = log Q or Y = lnQSolve for KT = {Y -Y } / SYSolve for T by interpolation from table or by equation

31 :

. .

32 4144 3311 . 100

100

33 .

T0

34

35

36 :

.

37

:

:

38 . . . . Q2.33 . : Q10/Q2.33 . K 39 . N .

.

n: .

Q2.33Q10Q10/Q2.33Qk=kQ2.33Tkn40 . .

:

41 .

.

n (years)2=6.33/n^0.5 Y10 - 2TLY10 + 2TU42 43 Q2.33 . .

Q2.33 . . Q11Q21Q31Q41Qi1/NQ12Q22Q32Q42Qi2/NQ13Q23Q33Q43Qi3/N44 Q2.33 . ( ) . 10 Q2.33 10 .45