ABSTRACT
Drainage is an agricultural water management practice that has been used for many centuries.[1] In early times, development of cities and commerce was dependent upon stable and bountiful agriculture requiring fertile soils and adequate rainfall or irrigation water. There is evidence of failure of early irrigation-based agriculture due to salt accumulation in the soils because of not understanding how to use drainage to leach the salt from the soil.[2] Areas with adequate rainfall to support permanent agriculture frequently also need drainage to manage excess water in the soil. Soils in low-lying areas were recognized by early farmers as the more fertile and productive soils, but these soils were also subject to periodic flooding and crop loss or damage. The goals for early drainage works seem to be centered on removing standing water from crops. Archeological evidence from the Mayan culture in Central America indicates that ridges or raised beds were constructed and used as planting zones to avoid inundation of crops, a very early form of surface drainage. Ancient Greek and Roman writings included instructions for construction of both surface and subsurface drains.[1]
Agriculture has evolved to a highly mechanized industry, and this has intensified the demands on drainage. Modern goals for drainage include a trafficable soil surface for timely planting and harvesting of crops using large machines; an aerated root zone that promotes good crop nutrition and minimizes disease organisms; sustained high crop yields; and an ability to maintain the salt balance within the soil profile.
