Variations in the Level o f Victoria Nyanza.
Lake Level Rain
Decades
1896 Port Alice Lubwa Port Victoria
Port Alice , Port Victoria
Amount Days Days
January 1
rn.
7*8
In. In.
6*9
In,
_
11 7"1 '•J.< gaBai 6*7 r— ." •— —
III 6*1 ■ IB s 6*3 — —* —-
February 1 5*7 • ■ 4*4 5*9 T- —
11 4-6 3*3 ' 4*3 ■. ik. —
hi 2’9 . • 2’5 3*6 —•
March 1 ■ 1 9 . . 2 "2 2*8 —• . : r . —
11 i *i 3*3 3*5 — . —
in
April 1
2*2 3*2 3*4 : —
2 7 - ' 2j 3 2*2 ,, I 5'40 4 - — .
11 3'2 3 9 3*4 3*9° ! 8 .Sv?..
hi
M a y 1
3*9 . 3*4 3*4 • 3*17 6
3*5 3-o 3*4 *85 6 . — . •
11 2*9 4*2 3*3 2*33 ' 4 —
hi
June 1
2*5 3*7 " 2*8 1*27 5 r—
i ’I 2*9 2*4 2*46 , 5' . — .
11 I "2 2’2 2*5 ’26 i — ,
in 2*1 2*3 2*1 *46 2 - "•r-r ■
J u ly 1 2*2 1*2 1*2 /08 2 2
II *7 - "2 V- *1 . *20 . 2 0
III ;o — 1*2 - x *7 *°3 i .0
August , 1 —0*6 . — 2*1 - 2*3 2*04 6 • 5..
- 11 - I'O - ‘8 - 2*4 2*06 6 3 ,
hi - 1*3 - 1*5 - - 2*0 , , *09 ■ — 0.
September 1 - 3*8 - 2*8 - 4 *i *20 2 /- 2
11 * - 5 - 1 - 4 *i - 5*2 •87 1 2 5
m - 5'9 -■¿*1 - 6*7 I '30 ■ i 0
October 1 - 7*5 - 7*0 - 7*3 •38 2 0
11 - 10*0 - 8*7 - 8*8 . i *34 3 2
hi -9 -8 -8*8 - 9*7 I 2*8/ 6 6
November 1 ' 18 *6 - 8 7 - 7*6 3*66 10 9
. 11 “ 4*4 -4 *2 f f - 2*7 7*21 8 6
m - 2/3 - I *7 - I/O 1*18 7 2
December 1 - 0-9 - 2*3 1 1*7 3*46 4 2
11 - 2*1 - 2*2 - 2*7 *97 3 - o'
h i - 2*2 - 3*4 1 2’4 *21 3 p .
Y e a r (Mean) 0*0 - - 0*Q . 0*0. I S - -
January (1897) 1" - 3*9 - 3 *5. “ 3**5 1 *08 2 i
11 - 2 7 - 2*5 - 2*1 *47 2 - 5
in - 1*9 - 2*6 - 1*9 1*20 2 0
February 1 - 3*o 1 1 ’5° - I *55 1*21 7
11 — 2*0. ' — o ’8o - *17 *59 ' 3 2
h i - 1 7 - 1*96 . - *44 1*82 : 3 X
NOTES ,
The observations on the rise and fall of the level of Victoria Nyanza were begun in January 1896,
by direction of Mr. Ernest J. L. Berkeley, H. M.’s Commissioner, who placed this work under
the charge of Mr. R. J. D. Macallister. There are at present three stations—
Port Alice, or Ntebe, the Lake Port of the Capital. The observations are made daily at noon.
The observers were Major A. E. Smith (January), Mr. Alex. Geo. Boyle (February to September),
and Mr. Fred, Pordage.
Lubwa, near the outlet of the Victoria Nile. Observer, up to the beginning of February 1897,
Mr. W. Grant.
Port Victoria, on Berkeley Gulf, in the N.E. corner of the lake. Observer, up to the end of
1896, Mr. R. J. D. Macallister ; since that time, Mr. C. W. Fowler.
At Lubwa and Port Victoria the observations are made at 9.30 a.m. Observations on the
rain-fall are made at Port Alice only, no gauges being available.
Care has been taken, when fixing the gauges, to prevent a subsequent settlement.
On beginning their work the observers were of necessity compelled to choose an arbitrary datum
level. In our abstract the datum level accepted is the mean level of the lake during 18.96,
In ¿is accompanying tables, the results are given by decades, as also by months.
In examining this interesting record it will be found that the influence of the rain-fall upon the
level of the lake is not so immediately apparent as ihjgbt have been expected. Thus a rain-fall of
2*36 in. on November 14, 1896, only caused a rise of the lake to the extent of 0*75 in., and the
heavy rains during October and November (16*64 in.) influenced the lake-level to the extent of
only about 5 in. Evaporation, no doubt, as also the irregular distribution of the rams over a lake
covering an area of 25,000 sq. miles, go far to explain this. •
The winds exercise a decided influence upon the level. I hey are regular land and lake breezes,
bio win c off-shore (from the E. or N.E.) in themioming, and changing about.noon to W. or S.W.
The lake breezes are more especially important, and Mr. Macallister remarks that a strong S.W
breeze will cause a rise in the level of the lake to the extent of from 1 to 3 in.
As the observations at two of the stations are made in the morning, the actual mean level is
probably a little higher than it is made to, appear from our abstract. In order to trace the influence
of the wind upon the lake level it would be necessary to establish a self-registering gauge, or to
make observations at least thrice daily.
Taking the mean of the three stations, we find that on January 1, the level stood 7*8 in. above
the datum, whilst on December g jj it was 3 3 in. below it, a difference of ii*i in. The level was
highest in the beginning of the years; lowest (-9*2 in.) during the second decade of October.
The extreme range amounted to 18*2 in. (Port Alice 19*0 in., Lubwa 17*5 in.. Port Victoria 18*2 in.)
It is desirable that similar observations should be made on the S.E. and W. shores of the lake.
The connection of these stations by lines of spirit levelling can hardly be looked for, for many
years to come.