For the attached measured precipitation-runoff data (in) (series of annual maxima) for watershed 68013 (WS-13) in Reynolds, Idaho, develop a computer program or spreadsheet to calibrate the runoff curve number, i.e., to find the runoff curve number that best fits the data.

1. The criterion to choose the curve number should be the minimum root mean square (rms), i.e., the value of curve number (in the possible range 1 ≤ CN ≤ 100) which minimizes the root mean square of the deviations between calculated and measured runoff.

2. The rms of the deviations is obtained by squaring the deviations, finding the mean of the squares, and taking the root of the mean of the squares.

3. Use Eq. 5-8 of the text to calculate runoff.

4. Generate a table of curve numbers, from 1 to 100, and corresponding values of rms.

5. Identify and print the minimum rms and corresponding CN.

Event	Precipitation (in)	Runoff (in)
01	0.980	0.0139
02	0.842	0.1162
03	0.220	0.0117
04	1.720	0.1614
05	0.300	0.0180
06	0.570	0.0758
07	0.571	0.1060
08	0.910	0.3275
09	0.070	0.0471
10	0.210	0.0714
11	0.220	0.1649
12	0.080	0.0121
13	0.760	0.0761
14	0.160	0.0047
15	0.150	0.0051
16	0.360	0.0074
17	0.360	0.0366
18	0.690	0.0620