| Term No. | Term Name | Term Description |
| 928 | S-curve, or S-curve hydrograph | A graph showing the summation of the ordinates of a series of unit hydrographs spaced at unit-rainfall duration intervals. It represents the hydrograp..... |
| 1776 | S-Value | Milliequivalents of exchangeable metallic cations in 100 grams of exchange (absorbing) complex...... |
| 8298 | S-Video | A video format offering a higher quality signal than composite video, but a lower quality than component video. This mid-level format divides the sign..... |
| 4137 | Sacrosanct land | Land unlikely to yield a tangible benefit from flood alleviation, such as common land, nature reserves, recreation areas...... |
| 2773 | Saddle siphon, or Hood siphon | A siphon having its duct formed of a U-shaped hood. The inlet lip of the hood is submerged below the full reservoir level and that of the outlet lip t..... |
| 2816 | SAF basin | Stilling basins designed by Saint Anthony Falls Hydraulic Laboratory, USA, for drainage structures. They have an end sill and a row each of chute bloc..... |
| 5389 | Safe velocity | The greatest velocity at which it is possible to let water flow in a drainage channel without causing erosion or washing of the banks...... |
| 3971 | Safe yield | With reference to either the surface-water or groundwater supply, the rate of diversion or extraction for consumptive use that can be maintained indef..... |
| 2387 | Safe yield of reservoir basin, or Safe yield of catchment | The annual runoff flowing from the basin into the reservoir that can be depended upon for utilization...... |
| 5999 | Safety fuse | A device consisting of a train of enclosed black powder that is used as a medium to convey a flame to an explosive. The flame will travel along the fu..... |
| 1208 | Sag correction | The amount by which soundings must be reduced to obtain true vertical values...... |
| 3757 | Sag pipe, or Sag line | Terms sometimes used for syphon or inverted siphon...... |
| 4608 | Sailab irrigation (a term used in India and Pakistan) | Irrigation by flood waters which are allowed to spread, without control, first on the bottom of rivers, then the surplus water flowing out through was..... |
| 2144 | Sajong soils, or Shachiang soils | Soils containing 85 per cent calcium carbonate and having lime concentrations of ginger root size...... |
| 4451 | Sakia, Saqia, Saqiya, Sakieh or Sakiyeh | A kind of water wheel used in Egypt for lifting water up to two metres. It consists of a double-sided all metal wheel that has volute-shaped compartme..... |
| 7815 | Salic horizon | Soil horizon enriched by soluble salts...... |
| 8807 | Salient features of a project | The important data of a project briefly listed by which its nature, magnitude and scope could be gauged...... |
| 6980 | Salientia | Toads...... |
| 7731 | Saline | Referring to water that contains dissolved salts, usually at concentrations from 10 000 to 33 000 mg/l...... |
| 7732 | Saline contamination | Contamination of water by intrusion of salt water...... |
| 5147 | Saline sodic soil | A soil with sufficient exchangeable sodium to interfere with the growth of most crop plants and containing appreciable quantities of soluble salts...... |
| 2138 | Saline soil | A non-sodic soil containing sufficient soluble salt to impair its productivity. The electrical conductivity of the saturation extract is greater than ..... |
| 5148 | Saline soil | A non-sodic soil containing soluble salts in such quantities that they interfere with the growth of most plants...... |
| 8815 | Salinity control | Abatement or prevention of salt water contamination of agricultural, industrial and municipal water supplies, or reducing alkaline salts and preventin..... |
| 9170 | Salinity control benefits | Benefits based on value of damage prevented, reduction in costs, and increased use, similar to flood control...... |
