| The Sanjiang Plain is located in the east of Heilongjiang Province.The area is fertile,with suitable climate conditions,good lighting conditions,the same season of rain and heat,large temperature difference between day and night,less pollution,suitable for crop growth,and great potential for agricultural production.The main crops are rice,corn and soybeans,which are the most important grain producing areas in China.However,after years of high-intensity development and cultivation,the local area has excessively extracted groundwater in order to increase the grain output,resulting in the continuous decline of the groundwater level in some areas.Under such a background,land managers need to know how to manage irrigation water scientifically,an urgent need that should be addressed to ensure regional food security and ecological security.In this paper,10 typical irrigation areas were selected for analysis,namely,Bawusan,Daxing,Hamatong,Jiangchuan,Jinxi,Longtouqiao,Songjiang,Wutonghe,Youyi,and Xi ngfu.An evaluation indicator system for irrigation water use efficiency is constructed.Three mathematical evaluation models are used to evaluate irrigation water use efficiency.I ndicator weights and scenario analysis are used to analyze the driving forc e of irrigation water use efficiency,and prediction models and evaluations are applied.Use the model to predict its development trend,optimizes the allocation of research regional irrigation water structure,and develops an irrigation water resources management decision support system for irrigation districts.The specific research results are as follows:(1)The evaluation of irrigation water efficiency plays an important role in the efficient use of agricultural water resources and the sustainable development of agriculture.A reasonable selection of efficiency evaluation indicators for irrigation water use is the premise of the effective use of those indicators,and the development of scientifically sound and rigorous indicator selection program is the key to correctly selecting the indicators.In order to make the evaluation of irrigation water use efficiency indicators more comprehensive and scientific,this paper constructs a new optimal model of evaluation indicators.By combining the DPSIR model with the ISD evaluation indicators model,a novel DPSIR-ISD evaluation indicators combination model was constructed.Ten riverside irrigation areas in the Sanjiang Plain of northeastern China were selected for analysis.The results show that the DPSIR-ISD model was used to reduce the number of indicators from 44 to 14;these 14 indicators reflected 91.88% of the original information.The DPSIR-ISD method proposed in this paper takes into account the completeness and simplicity of the indicators system,and is more in line with the actual situation in the field.The DPSIR-ISD method has obvious advantages in indicator optimization.These results can provide a simpler and more convenient system for optimizing indicators for the study of evaluation indicators used to analyze irrigation water use efficiency.(2)Using FA-PP model,EWM-TOPSIS model and CRITIC-TOPSIS model to evaluate the irrigation water efficiency of 10 typical irrigation districts in the region.The evaluation results showed that the comprehensive indicatorof irrigation water efficiency in the irrigation area ranked from high to low: Wutonghe > Songjiang > Jinxi > Jiangchuan > Xingfu >Bawusan> Daxing > Hamatong > Longtouqiao > Youyi,(3)Based on the evaluation indicator projection direction and indicator weights obtained from the evaluation model,the key driving factors for irrigation water use efficiency in the irrigation area were analyzed based on the serial number theory,and the driving mechanism for irrigation water use efficiency in the irrigation area was analyzed using scenario analysis methods.Taking the Wutonghe irrigation area as a typical irrigation area,the ARIMA prediction model is used to predict the value of each evaluation indicator,and the time series of the evaluation indicator from 2000 to 2028 are evaluated by the EWM-TOPSIS model to predict the irrigation water efficiency of the irrigation area.To predict the future development trend of irrigation water efficiency in its irrigation district.The results show that the evaluation indicators R3,R5,R4,S1,D5,I8,S9,and S2 are the key driving factors for irrigation water efficiency in irrigation areas.Irrigation area irrigation water efficiency is a comprehensive evaluation result.Although the driving force of each evaluation indicator is different,the driving force of a single indicator is not prominent.The future development trend of irrigation water efficiency in Wutonghe irrigation district is positive and positive.By 2028,the comprehensive indicator of irrigation water efficiency in Wutong River Irrigation District will increase by 64% compared with 2000 and by 11% compared with 2018.(4)Based on the sequential least squares programming optimization algorithm of gradient method,an optimal allocation model of irrigation water under the constraint of irrigation water efficiency is constructed,and the optimal allocation of surface water resources and groundwater resources in the researched irrigation districts is optimized to optimize the local irrigation water structure.The optimization results show that the groundwater irrigation water consumption of Jinxi irrigation district,Songjiang irrigation district,Youyi irrigation district,Jiangchuan irrigation district,Bawusan irrigation district and Daxing irrigation district are all reduced by more than 50%,and the overall groundwater irrigation consumption is greatly reduced.The water use structure has changed significantly,and the water use structure is more reasonable.After the irrigation water efficiency constraint coefficient is added,the groundwater irrigation volume is reduced by 8.72%,the reduction is obvious,which can greatly alleviate the local groundwater over-exploitation situation.(5)Research and development a decision support system to optimizate irrigation water allocation under irrigation water efficiency constraints.The system has simple interface design,clear function display,and strong human-computer interaction capabilities.The system adopts modular design,which is divided into two parts: irrigation water efficiency evaluation module and irrigation water optimization configuration module.The module functions are designed independently,and users can formulate and modify relevant parameters according to the actual situation of each irrigation area. |
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