The increasingly lack of water resourcesaffects and restricts the potential development of modern society and willbecome the main problem of the global water resources and environment in thiscentury 1.
The world population has doubled in thepast 60 years, a total of over six billion inhabitants with an increasingdemand for food and other consumer goods. This made the men should explore newareas and to get a constant increase of productivity, food quality, reductionof production costs and using in particular the irrigated agriculturerationally.China is not only a country with shortagewater resources but also a big agricultural country with a large population. Itis also a big country for agricultural water uses 2, 3. At present the totalagricultural water utilization in china estimated about 60% of the total waterutilization in the whole country 4, 5. Water-saving agriculture is a highdegree of agricultural rational use of water. Water-saving agriculture shouldbe developed on the basis of water-saving technology 6, 7.
Water-savingagriculture technology is the basic work of developing Water-saving agriculture8, 9. As an important part of Water-saving agricultural technology,Water-saving irrigation technology was a variety of irrigation measures, suchas sprinkler irrigation, drip irrigation etc. To effectively utilizeprecipitation and irrigation water according to the water demand law of cropsand the local water resources conditions 10As a rule, pressurized irrigationsystems are composed of water lifting devices, piped networks, water deliverydevices, and pressure and water control devices. At times, because of thetopography, no water lifting devices are required and water gravitates into thesystem.
Irrespective of whether pumps are used or not, the water in theirrigation system is always under pressure. The magnitude of pressure dependson the requirements of a particular technology. Generally, localized irrigationsystems operate at lower pressure than sprinkler irrigation systems. It istherefore necessary that during the preparation of the designs and bills ofquantity (Module 8 and 9) the pressure requirements of the system are clearlystated and the equipment to meet these requirements is identified.