CLASSIFICATION OF IRRIGATION SCHEMES

Irrigation Projects are divided into the following three categories viz., Major, Medium and Minor Projects. The criteria of classification is as under:

• Projects having CCA more than 10,000 ha. are classified as Major Projects
• Projects having CCA more than 2,000 ha. to 10000 ha. are classified as Medium Projects
• Projects having CCA less than 2,000 ha. are classified as Minor Projects

Irrigation Projects include storage dams, diversion works, barrages, lift irrigation schemes and tube wells.

CIassification of Irrigation Water Quality

All irrigation waters contain some dissolved salts. Dissolved salts are present because some chemical elements have a strong attraction for water and a relatively weak attraction for other elements. Two such chemical elements, for example, are sodium and chloride. The amounts of these elements contained in water must be very high before sodium will combine with chloride to form the solid material sodium chloride, common table salt.

The total amount and kinds of salts determine the suitability of the water for irrigation use. Water from some sources may contain so much salt that it is unsuitable for irrigation because of potential danger to the soil or crops.

Irrigation water quality can best be determined by chemical laboratory analysis.

1. Storage governed
2. Hydraulically-governed
3. Inertia-governed
4. Controlled/regulated
5. Pressurised command