LAND DRAINAGE BY MEANS OF PUMPS. 19 
results ill any oilier case of iinderclraiiiage. as the problems to be 
encountered are similar. A very large percentage of the bottom land 
reclaimed by means of ptinips is now very completely tile drained. 
Nearly all the small surface ditches have been replaced vrith tile. 
On some of the districts even the larger lateral ditches have been 
replaced with large the. and the plans for the drainage of new dis- 
tricts now call for tile drams where formerly open ditches would 
undoubtedly have been recommended. On the Langelier District, 
near Havana. 111., practically all the open ditches, both large and 
small, have been replaced with tile drains, until only about 2,000 
feet of open ditch now remain. Thus far the system has been satis- 
factory, although it has not yet experienced an extremely wet sea- 
son. Future experience on this district will furnish valuable data 
for guidance in the design of systems winch are to include tile drams. 
The replacing of open ditches with tile drains will reduce the main- 
tenance charges on the interior drainage channels and will effect a 
saving in land. The question of laying tile drains in the bottoms 
of broad, shallow depressions to be used as fioodways for storm run- 
off deserves careful consideration in planning drainage improve- 
ments of this character. By laying tile drains a few feet below the 
bottoms of open ditches which are no longer deep enough to give a 
sufficient depth of drainage the combination of ditch and underdrain- 
age may be very cheaply attained. 
On account of the surface erosion and consequent sedimentation 
in the main ditches small open surface field ditches or laterals empty- 
ing into the main ditches are highly objectionable unless for some 
distance back from the junction they are dug as deep as the bottom 
of the main ditch. The difficulty could be avoided by the use of 
some sort of permanent and stable masonry inlet: otherwise small 
ditches should be replaced by the. 
GRAVITY SLUICEWAYS. 
Ill the case of districts where the river falls low enough during 
the latter part of the summer to afford an outlet for gravity drain- 
age, sluiceways, so arranged that they may be opened when desired. 
should be built under the levee near the pumping plant. The sluices 
should be composed of one or more parallel pipes laid nearly level 
and provided with suitable valves. The length of the pipes will 
naturally be 100 feet or more. Metal, concrete, or vitrified sewer 
pipe may be used in then construction. Both ends should be pro- 
tected with strong concrete bulkheads, and cut-off walls should be 
placed around the pipes at intervals along then length to prevent 
seepage along then exterior surface. Cracking and failure of these 
end bulkheads, one of the commonest accidents in drainage districts, 
show that they must be made with special care, amply deep, and of 
