For smaller tanks with water depths not exceeding 2.5 m in favorable soils such as red and white gravel, red and black loams, side slope may be taken as \(\frac{1}{2}\) : 1 and 2 : 1 for larger ones up to 5 m in depth. The slopes may be kept in between 2 : 1 and 2 \(\frac{1}{2}\) : 1 in light sandy, black cotton or clayey soils.

This difference is fixed on a compromise basis in order to obtain overall economy and efficiency. It is kept from 0.3 to 0.6 m for small and medium-sized tanks and is rarely allowed to exceed 0.9 m.

The top-level i.e. crest level of tank weir is kept at F.T.L. The extra water is discharged over surplus escape weir when tank is full up to F.T.L. The design of length or capacity of this surplus escape weir is such that water level in tank never exceeds M.W.L.

A highly irregular alignment increases circuitry or length in excess pf airline distance which barge tow must travel. The existing channels generally have a length of about 50% greater than air-line distances. Hence, alignment should be as straight as possible.

Pipe sluices are earnware or cement or cast iron pipes which may be used in place of masonry culverts in case of very small slices. The earnware pipes may get fractured or leakage through ir joints may take place resulting in a breach. The pipes can neir be examined nor repaired easily without cutting open bund. They are not adopted when depth below F.T.L exceeds 2.5 m or so.

A breaching section is a length kept lower and weaker than remainder of bound so as to localize a breach in that length only. A breach occurring in a tank supplements surplus power to a reasonable degree to greater security both of tank itself and those below it in group.

Dipper dredgers are used on small projects and are merely floating power shovels. Ladder dredger is used when excavated materials are to be discharged at a considerable distance from dredge. The disadvantage of suction dredge is that it cannot operate in rocky or Shoulder River reaches.

The availability of sufficient water depth in waterway is chief requirement for navigations and for safe and economical navigation, a minimum depth of 2.7 m is generally required. Lesser depth in rivers completely eliminates possibility of towing ships and causes an increase in unit cost of transport and a depth of 3.7 m is generally desired in final development.

The width of horizontal floor of Type-A and Type-D weirs should not be less than 2(D + H) and in important works, width can be increased to 3(D + H). where D is height of drop wall and H is maximum head of water over wall. The rough stone apron forming a talus below last curtain wall generally vary from 2.5(D+ H) to 5(D + H) depending upon nature of soil and velocity and annual probable quantity and intensity of run-off.

The cubic content between two successive contours is computed as (A₁ + A₂) x h/2. The required storage capacity of tank is summation of all cubic contents between successive contours.