When ground water-table is nearer to natural surface, water which has entered subsoil may join saturation zone or underground reservoir to maintain a continuous direct flow. Due to difference of level, water directly flows from canal to underground reservoir through soil pores.

The water requirement during Rabi season reduces to about 2/3^rd times full supply, capacity factor usually varies from 0.60 to 0.70 for rabi season. The cropped area is increased in order to improve this factor.

The dividing line between catchment areas of two streams is called ridge or watershed. The main watershed between two streams divides drainage area of two streams.

When a channel is aligned proposed curve should be as gentle as possible. It leads to silting on convex side and scouring on concave side due to disturbance of flow caused by curves. Stone pitching is sometimes proposed to avoid erosion and scouring.

In this canal river slope is much steeper than canal bed slope so refore canal encloses more and more area between itself and river. It should be noted that more fertile lands are located at lower levels. In or words we can say contour canal irrigates only on one side as or side is higher.

Seepage and Evaporation are two main reasons for loss of canal discharge. Out of se, seepage loss is most significant in initial stages (about 40%). Evaporation loss may range from 2 to 3% of total canal discharge.

This method of distribution of available water into various canals is called canal regulation and flow from main canal is followed by branch canals and n to distributaries. The flow distribution depends on demand for water on various canals.

Cultivable Command Area CCA = 8000 x 80/100 = 6400 hectares
The area to be irrigated = CCA x Intensity of irrigation = 6400 x 50/100 = 3200 hectares
The water required at head of distributary = 3200/2000 = 1.6 cumec.

An inundation canal is a canal which gets its supplies only when water level in river from which it takes off rises during floods. They obtain ir supplies through open cuts in banks of river.

After development of canal system revenue obtained from cultivators is such that it is more than maintenance expenditure. This exceeding amount of revenue is so adjusted that it is about 2% of cost of canal system. With this rate, total cost of project will be recovered in about 50 years.