Note 13 — Chapter II · The Designing of a Canal.

A canal has an unmetalled driving road—called the “patrol road” or “inspection road” on one bank. This road is reserved for the use of officials. Otherwise, it would soon be cut up and worn away, and the cost of repairs would be excessive. The patrol road should be on that bank which is, in the morning (the time when inspections are usually made) in the shade of trees planted on the landward side. Trees are not usually planted near the water edge as they are sometimes blown down. In Northern India the canals generally flow in a southerly direction, so that the left bank is best for the patrol bank. On the other bank there is a bridle road which is open to the public. Near a rest house—unless there is a bridge actually at the place—the patrol road should be on the same bank as the rest house. It can if necessary cross at the first bridge. Frequently there is also on one or both sides of the canal a “boundary road,” which is open to the public, along the toe of the outer slope. Along a distributary there may be a boundary road on one side. It is generally the only road which can take wheeled traffic, and in this case it should be reserved for officials unless money is provided to keep it always in repair. Officials have to be on tour for weeks or months at a time, and in all weathers. Their baggage carts also have to precede and follow them. Anything which facilitates their touring about and seeing things for themselves is, in India, most desirable. At a watercourse crossing the boundary road along a distributary should be taken by a curved incline up on to the bank and down again. Thus not only is the cost of a culvert saved, but any touring official who is driving obtains a view of the channel which he cannot get from the boundary road.