Water Resources Management - Practices of Irrigation and On-farm Water Management - page 153

Operational and Maintenance Measures Directing Reduced Water Loss
A wide range of operational and maintenance (O and M) measures directed at
reducing water losses and consumption may be employed. Several of these mea-
sures, including leak detection, repair of water distribution lines, may be part of
normal infrastructure maintenance. Other measures, such as installing new meters
on unmetered accounts, reservoir renovation, water pressure reduction, etc. may be
aimed at reducing water loss.
Plumbing Fixtures and Devices in a Voluntary Program
Motivation for voluntary retrofitting of plumbing fixtures (to more water-efficient
ones), or the distribution of subsidized or free water-saving devices should be done.
Efficient toilets and other devices can save a substantial amount of water in homes.
The American Water Works Association ( 1999 ) reported that in a typical single fam-
ily home, which has no water conservation fixtures, toilet use accounts for 27.7%
(or 20.1 US gallons per capita per day). By installing water-efficient ultra low-flush
toilets that use 1.6 US gallon per flush, toilet use declined to 19.3% or 9.6 US gallon
per capita per day.
Agricultural Sector
Removing of Pricing Subsidies
Withdrawing of subsidies from water pumping (in the form of subsidies in diesels,
electricity, etc.) will certainly make awareness regarding its efficient use, minimiz-
ing conveyance loss, and conservation measures.
Water-Saving Irrigation Scheduling
Alternate furrow irrigation : Experimental results suggest that water use can
be decreased by almost 33% by irrigating alternate furrows instead of every
furrow. Most of the water savings, however, occur on the lower part of the
field.
Alternate wetting and drying of rice fields : In rice cultivation, instead of con-
tinuous ponding of the field to a certain depth, irrigating after 3-5 days of
disappearance of ponded water saves about 30-35% water without reduction
in yield.
Soil drying during ripening of crop : In most crops (especially in cereals), we are
interested to produce higher grain yield but not the straw yield. Soil drying
during the grain-filling period of rice and wheat enhance early senescence.
The grain-filling period may be shortened under such a condition, but a faster
rate of grain-filling and enhanced mobilization of stored carbohydrate from
vegetative parts to grain minimize the effect on yield. Thus, water demand
can be minimized without reduction in yield.