Agricultural drainage : a retrospective of forty years experience / J. Bailey Denton.
- John Bailey Denton
- Date:
- 1883
Licence: Public Domain Mark
Credit: Agricultural drainage : a retrospective of forty years experience / J. Bailey Denton. Source: Wellcome Collection.
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![ment in all soils of uniform character in relation to both subsoil and configuration of surface.] Mr. Parkes adopted the parallel system at wider intervals, adding that it is the subterranean water to which excessive and injurious wetness is attributable; and that if such water be not removed and kept down at a depth exceeding the power of capillary attraction to elevate it too near the surface, no drainage can be efficient. And Mr. Gisborne, in the Quarterly, advocated the parallel system for the reasons assigned by Mr. Parkes, christening the rain, or surface water, top, and the subterranean water bottom water, and charac- terising all water existing in the soil which yields to gravity, and is discharged by the drains, the water of drainage;' and that which resists •, gravity, and is held up in the soil by capillary attraction, the water of attradioti. I do not wish to place my single views in opposition to opinions so eminent and deservedly influential as those I have quoted, but as the object we have in view is to deal practically with the subject, and to profit by the past, I do not hesitate to say that experience has, to a certain extent, modified, if not contradicted, the distinctions here quoted, and has shown that there are circumstances and positions under which parallel equidistant drains, however near, will not necessarily drain land suffering from subterranean or spring waters, but that special causes of wetness must be met by special treatment. It appears in fact that there is another description of water which causes injury to land, and which, borrowing the style of phraseology adopted by Mr. Gisborne, may be called the water of pressure, that water which having a higher source than the land drained, rises by hydrostatic pressure through porous veins, or by diffused means, to the surface to the utter disregard of any parallel system of drains.^ A con- sideration, too, of the varying inclinations of surface, of which instances will frequently occur in the same field, necessitates a departure from uniformity, not in direction only, but in intervals between drains. Take, for instance, the ordinary case of a field, in which a comparatively flat space will intervene between quickly rising ground and the outfall ditch. It is clear that the soak of the hill will pervade the soil of the lower ground, let the system of drainage adopted be what it may ; and, there- fore, supposing the soil of the hill and flat to be precisely alike, the existence of bottom water in a greater quantity in the lower lands than in the higher, will call for a greater number of drains. It is found, too, that an independent discharge or relief of the water coming from the](https://iiif.wellcomecollection.org/image/b21782568_0032.jp2/full/800%2C/0/default.jpg)
