Water Resources Management - Practices of Irrigation and On-farm Water Management - page 162

• irrigation effluent

• drainage outflow

(iii) Rainwater harvesting at farm pond, lakes
(iv) Augmenting natural recharge
(v) Inducing artificial recharge
(vi) Sharing of international rivers
(vii) Network rehabilitation
(viii) Reallocation through volumetric constraints
(ix) Import of virtual water
(x) Use of super absorbents
(xi) Implementing dual water supply system
(xii) Implementing dual water use - aquaculture in rice field

5.3.2.2 Description of Different Approaches

Development of New Supply Source

Water is available on the planet both on the surface and under the surface of the
earth. The water on the surface is termed “surface water”, and the water under the
surface is termed “groundwater.” Surface water and groundwater are both important
sources not only for human use but also for ecological systems.

Surface Water

Surface water is renewable, usually within few months or a year, while groundwa-
ter is also renewable, as it takes several months or a year. Development of surface
water source includes construction of new dams and reservoirs, excavation of ponds,
rehabilitation of natural water bodies such as lakes, rivers, and other lowlands.
Rubber dam, a flexible and technically and economically sound technology, has
been increasingly used in many parts of the world. But in all cases, environmental
and ecological perspectives should be taken into consideration. Details about the
rubber dam has been described in Chapter 11 , Volume 1.

Groundwater

The agricultural sector is the largest consumer of water. For proper development
of groundwater, a systematic survey and determination of aquifer characteristics
is essential. Groundwater should be withdrawn based on safe yield concept. Safe
yield of each aquifer should be determined, and groundwater should be exploited
accordingly.

Safe Yield

Intensive groundwater development in many parts of the world has caused rapid
decrease of groundwater level. This has resulted in aquifer depletion, water quality