262 
Journal of Agricultural Research 
Vol. XI, No. 6 
months were very dry and little pumping was done. All the field ditches 
were cleaned out, and the entire area was cultivated. (See Table X.) 
tables of rainfall and run-off 
In the tables (I-X) the monthly and yearly summaries for the 
various districts are given. At the end of each of the tables is a 
statement of the average amounts of rainfall, run-off, etc., for the period 
covered by the records for that district, proper corrections having been 
made for such times as the records were temporarily suspended or the 
conditions as to rainfall or run-off were abnormal. As each district 
has local characteristics, it is considered that any figure obtained by 
taking a general average of the values for all of the districts would be 
of no special significance. However, certain of the districts and years 
have been selected as being typical of conditions prevailing on lands 
reclaimed from the wet prairies of southern Louisiana. These districts 
and years are as follows: Lafourche Drainage District No. 12, Subdis¬ 
trict No. 3, 1913, 1914, 1915; Unit No. 1, Poydras, La., 1914, 1915; Des 
Allemands Polder No. 1, 1914; Jefferson Drainage District No. 3, .1914, 
1915; Gueydan Drainage District, Subdistrict No. 1, 1915. Where the 
period during 1915 did not cover an entire year, the yearly totals have 
been corrected proportionately before averaging. The results are as 
follows: Average rainfall, 48.95 inches; average run-off, 21.56 inches; 
average number of days on which pumps operated, 90. 
The above annual rainfall is somewhat below the mean annual rainfall 
for New Orleans, but it is believed that the percentage of rainfall appear¬ 
ing as run-off (44 per cent) is not greatly in error for average conditions. 
With this percentage and a mean annual rainfall of 56 inches, the amount 
of run-off to be expected per year under average conditions would be 
24.6 inches. 
Table III. —Rainfall and run-off on Lafourche Drainage District No. 12 , Subdistrict 
No. I , April , IQ14 y to December , 1915, inclusive 
Month. 
Rain¬ 
fall. 
Run¬ 
off. 
Rain¬ 
fall in 
run¬ 
off. 
Pumps 
ran. 
Rain 
fell. 
Month. 
Rain¬ 
fall. 
Run¬ 
off. 
Rain¬ 
fall in 
run¬ 
off. 
Pumps 
ran. 
Rain 
fell. 
1914. 
April. 
In. 
S’ 20 
In. 
3-39 
•95 
.64 
3 - 14 
1. 94 
P.ct . 
65. 2 
33 ' 3 
Days. 
3 
Days. 
2 
1915—Continued. 
April. 
In. 
0.00 
In. 
0.00 
P.ct. 
Days. 
0 
Days . 
0 
May. 
2. 85 
4 - 63 
8. 00 
5 
4 
May. 
1.61 
. 00 
• 0 
0 
2 
June. 
13-8 
39-3 
25-9 
2 
4 
June. 
1.66 
. 00 
• 0 
0 
3 
Tilly. 
7 
7 
July. 
5*09 
6 . 99 
2.10 
2.51 
. 00 
49.4 
. 0 
3 
3 
August... 
7 - 50 
O7. 00 
5 
8 
August. 
0 
12 
September a 
b A 
September. 
. 00 
. 0 
0 
3 
October. 
i w 
, OO 
•44 
8. 03 
5-37 
2 
0 
October c . 
November. 
10. 90 
3*32 
73 - 6 
161. 7 
10 
3 
November. 
I- 55 1 
1-30 
•32 
. 00 
20. 6 
X 
3 
December. 
14 
4 
December. 
• 0 
0 
1 
Total. 
J- 2 * AO 
23 - 90 
56.4 
48 
32 
Total. 
33 - 2 3 
20. 57 
61* 75 
4 * 
36 
1915- 
January. 
4.40 
6.30 
2. 23 
7.06 
6.65 
4-03 
160.6 
15 
14 
9 
2 
Averages 
for pe¬ 
February. 
105.5 
180.8 
4 
riod (1.58 
years).... 
March. 
3 
47 - 7 
28.0 
58-7 
56. 7 
42.9 
a Averages do not include September, 1914. & Not included in total. 
c The record for October, 1915, is omitted. 
