Study On Water-saving Transformation Of Well And Canal Irrigation District In Hebei Province And Its Influence On Groundwater Level

Hebei Province is one of the provinces with the largest exploitation and utilization of groundwater in China.Due to over-exploitation of groundwater,a series of environmental and geological problems such as drainage of aquifers,drying-up of spring water,ground subsidence,intrusion of sea salt water and motor shaft scrapping have caused serious impacts on Hebei's sustainable economic development.Based on a large number of domestic and foreign related files and essays,this paper discusses the mode of developing water-saving irrigation with theoretical and experimental methods.This paper also puts forward a suitable developing mode of well and canal irrigating district of Hebei Province.The main conclusions are as follows:(1)According to the water resources data of Shijin irrigation area from 1980 to 2000,the high water level of Shijin irrigation area occurred in September,and the depth of groundwater was between 5.0m ~ 15.0m.The low water level occurred in June,during whichthe depth of ground water is between 5.0m ~ 20 m,and the depth of the western region of groundwater is relatively large.At the same time many problems exist in Shijin irrigation area,such as water shortage,the aging and dis-repairing of the facilities,seriousphenomenon of abandoning wells,unreasonable water fees,and the over-exploitation of groundwater.(2)Through the still-water test,measure the Water use coefficient of canal system?we can determine the appropriate field size of the canal,the length of the plot and the water level of the irrigation system.Based on experiments,the plot length of 30-50 m and the single wide flow of 3-5L /(s · m)are appropriate.After comparison and selection,we selected the suitable irrigation and drainage modefor Hebei Province: Channel-well-in-one mode and Channel-well-both mode.(3)Through the experiment of winter wheat nitrogen fertilizer,winter wheat phosphorus fertilizer,winter wheat potassium fertilizer test and winter wheat irrigation system,it was concluded that with the increase of irrigating and fertilizer amount,the yield of winter wheat increased first and then decreased,that is,too much water and fertilizer treatment can not increase production,but will inhibit the yield increase.Through the combination of irrigation and drainage works and the development of irrigation system,the decline of groundwater is effectively inhibited.We also formulated fertilization program and supporting agronomic measures.(4)During the period from 2007 to 2009,groundwater table observation was carried out in the test area.The low water table of groundwater level of current year usually occurred in mid-April,while the high groundwater level was generally in late October.Since 2008,the increase of groundwater,is mainly related to natural rainfall which can greatly reduce the over-exploitation of groundwater especially during the irrigation season.At the same time,the field water distribution system,water-saving technological transformation,water conservation action and strict management measures also played active roles,according to this reality,we can approximately think that total groundwater over-exploitation of the is controlled,groundwater level degradation trend is eased.