| 47.0 | 1 | 0 | 78 | 38 | 29 | 146
September| 97 | 57.0 | 7 | 21 | 13 | 38 | 18 | 97
October | 61 | 90.5 | 8 | 7 | 9 | 25 | 12 | 61
November | 50 | 60.0 | 4 | 13 | 5 | 17 | 11 | 50
December | 370 | 99.0 | 126 | 108 | 33 | 59 | 44 | 370
---------+-------+-------+-------+-------+-----+-----+-----+--------
1910.
---------+-------+-------+-------+-------+-----+-----+-----+--------
January | 2,410 | 136.0 | 1,109 | 1,020 | 67 | 117 | 97 | 2,410
February | 839 | 117.5 | 481 | 126 | 56 | 75 | 101 | 839
March | 208 | 7.5 | 13 | 43 | 15 | 13 | 124 | 208
April | 321 | 65.0 | 17 | 195 | 43 | 43 | 23 | 321
May | 197 | 84.5 | 58 | 54 | 22 | 24 | 39 | 197
June | 1,505 | 124.0 | 786 | 535 | 49 | 88 | 47 | 1,505
---------+-------+-------+-------+-------+-----+-----+-----+--------
Total | 6,522 | 920.0 | 2,613 | 2,122 | 515 | 611 | 661 | 6,522
=========+=======+=======+=======+=======+=====+=====+=====+========

In order to relieve the situation at such times, the expedient of
raking was tried. This was first attempted with the filters filled
with water; the effluent was first shut off in order to prevent a
downward flow of water, and the filter was then raked or harrowed
from boats. This method was not satisfactory, however, as the work
was neither as uniform nor as thorough as necessary. Later, the
filters were drained to the necessary depth, and the surface of the
sand was thoroughly stirred with iron garden rakes. The filters were
then filled with filtered water through the under-drains and put in
service.

This latter method proved so satisfactory that it has been resorted
to at all times when the work was at all pressing. When the runs
were of short duration, and the depth to which the mud had
penetrated the filter sand was slight, a raking seemed to be nearly
as effective in restoring the filter capacity as a scraping; it
could be done in 8 hours by 3 laborers, and there seemed to be no
ill effects from lowered efficiency.

~Table 3--Turbidities.~
Average by Months.
(United States Geological Survey Standard.)
==========+============+=============================================
| | ~Reservoirs:~
| +-----