Proceedings of Eighth Annual Meeting 115 



offers ready outlet for an isolated picket and a small pipe line into 

 such a sewer or catch basin will bring about good drainage at a 

 comparatively low cost. The advantage of under drainage is its 

 permanence and the subsequent reduced cost of maintenance. Open 

 ditches unless through heavy clay or very solid soil should always 

 be cut with sloping sides and a V cross-section. But even the most 

 carefully constructed open ditches will overgrow in time and may be- 

 come blocked. They require constant inspection and periodic clean- 

 ing. On the other hand, open ditches have earned their place in mos- 

 quito control work because they permit a far greater number of 

 breeding spots to be successfully done away with in a single season 

 than any of the other methods and because the cost of maintenance 

 is as a rule only a fair proportion of the first cost. The best drain- 

 age systems on the upland are planned so that the water will be 

 completely drained from the swamps or pools and swiftly carried 

 to a main brook, river, pond or tidal stream where breeding will be 

 quickly destroyed. Sometimes, however, such a plan cannot be 

 worked out and partial, drainage is the best that can be obtained. 

 Under such circumstances the water is gathered into a central "sump" 

 or ditch where it is later treated with oil. This system has such 

 obvious draw-backs that it should be used only when no other means 

 can be utilized. 



As to the cost of installation of the practical drainage system, 

 the remarks made above in regard to the design and construction 

 apply with equal force to the cost. Each place to be drained pre- 

 sents so many individual features that so called average cost figures 

 are not of much practical value. It is easy enough to declare glibly 

 that to drain a salt marsh requires so many feet of ditching and 

 that the cost per acre should be a certain sum but you are paving 

 the way for trouble when the man in the field finds that in his case it 

 simply can't be done with that amount or at that price and then you 

 have to explain just where the fallacy occurs. And the deeper one 

 studies into this subject the more firmly one becomes convinced that 

 figures of ditching in one locality form no basis of comparison for 

 figures gathered in another locality and do not give sufficient data > 

 for a conclusion as to an approximate general quotation of the fair 

 cost of drainage work per given unit. And as the work in different 

 localities differs in cost, so does the cost of the work from year to 

 year fluctuate for it is primarily dependent on the cost of labor, 

 which is a .variable quantity. As the labor cost is the big item, it is 

 customary in many organizations in quoting cost figures to derive the 



