| Irrigation District is the relatively dense regions of the human water-related activities,especially large-scale irrigation district of the channel and well irrigation in semi-arid regions.Circulation and transformation of surface water and groundwater of large-scale irrigationdistrict in semi-arid regions are deeply influenced by human water-related activities. Coupledwith the impact of human’s other economic activities, a series of hydro-ecological problemsappeared increasingly in large-scale irrigation in recent years. For example, in the early1980sand before, hydro-ecosystems of Jinghuiqu Irrigation District was in good condition. Sincethe1990s, with the rapid socio-economic development, water consumption dramaticallyincreased, combined with decreasing in regional precipitation, sharp drop in Jing River runoffand not perfection in water pricing system and management system, groundwater has beenexploited in large. As a result of over exploited groundwater, large-scale groundwater leveldeclined, the range of descent funnel continuously expanded, resulting in a series ofhydro-ecological problems such as sink, crack, deterioration of water quality, less foodproduction, soil pollution, soil salinization and soil fertility decline, etc.These not only hinder the sustainable development of society and economy oflarge-scale irrigation district in semi-arid regions, but also pose a serious threat to watersafety, food security and ecological safety.However, the current hydro-ecological monitoringmethods of irrigation district stillremain in the backwardness of the artificial hand-monitoring, also limited to the groundwaterlevel, channel water, precipitation, and a few other factors, even no monitoring. For example,Jinghuiqu Irrigation District began artificial groundwater observation in1952, butobservation wells almost scrapped at present, the observation has been suspended for manyyears. Therefore, facing the increasingly serious hydro-ecological problems of large-scaleirrigation district in semi-arid regions，it is very significant to carry out studies of dynamicmonitoring and comprehensive evaluation of hydro-ecosystems for data acquisition andcomprehensive analysis in the study of the hydro-ecological coupling, based on advanced technology such as computer, GIS and RS, etc.On the basis of comprehensive and systemic summarization of the existing researchresults, from the point of the structure, features and the relevant problems of thehydro-ecosystems of large-scale irrigation district in semi-arid regions, a deep research wascarried out on a dynamic monitoring method, monitoring index system and spatial databaseof hydro-ecosystems in the paper. A set of comprehensive monitoring method systems thatconsist of “automatic and dynamic monitoring networks, satellite-based remote sensingmonitoring, a socio-economic survey and field experiments” is proposed. A set of scientificand reasonable monitoring index systems is defined. And the spatial database based onGeodatabase model is built. For Jinghuiqu Irrigation District, automatic and dynamicmonitoring system of main hydro-ecological factors is designed and realized. Finally, on thebasis of hydro-ecosystems dynamic monitoring spatial database, research on comprehensiveevaluation on quality of the hydro-ecosystems is carried out, and case analysis of JinghuiquIrrigation District is done. The main research achievements of the dissertation are as follows.(1)The concept, content and monitoring method system of hydro-ecosystems oflarge-scale irrigation district in semi-arid regions are discussed in detail. The generalframework structure of hydro-ecosystems dynamic monitoring of large-scale irrigationdistrict in semi-arid regions is given. A set of comprehensive monitoring method systems thatconsist of “automatic and dynamic monitoring networks, satellite-based remote sensingmonitoring, a socioeconomic survey and field experiments” is constructed. The “automaticand dynamic monitoring networks” and “satellite-based remote sensing monitoring” aredesigned in detail.(2)The data involved in research on hydro-ecosystems of large-scale irrigation district insemi-arid regions are analyzed in detail. And based on this, a monitoring index systemconsisting of two hierarchies and61individual monitoringindexes was established forhydro-ecology dynamic monitoring of large-scale irrigation district in semi-arid regions.(3)The data involved in research on hydro-ecosystems of large-scale irrigation district insemi-arid regions are classified in detail. On the basis of this, a spatial database model ofhydro-ecosystems dynamic monitoring of large-scale irrigation district in semi-arid regions isbuilt based on GeoDatabase modeland hydro-ecosystems spatial database is designed and realized.(4)Automatic and dynamic monitoring system for main hydro-ecological factors inJinghuiqu Irrigation District is designed and realized. The system canmonitorthe dynamicchanges of groundwater, soil water and canal waterremotelyand real-timely. The system hasmany advantages such as advanced technology, reasonable structure, friendly interface andsimple operation, etc. Problems that existed in artificial observation for hydro-ecologicalfactors in irrigation district, such as low precision, not real-time and low-efficiency are solved.This system has great application value.(5) On the basis of detailed analysis of evaluation index system construction methodsand models, weights determine methods and models, comprehensive evaluation methods andmodels in the relevant fields, a set of composite optimization methods and models that aresuitable for comprehensive evaluation on quality of hydro-ecosystems of large-scaleirrigation district in semi-arid regions are established. The composite optimization methodsand models consist of “Analysis, AnalyticHierarchy Process, Variable Weights Model ofHardarmard Product based membership and fuzzy comprehensive evaluation approach”.(6)On the basis of systemic analysis of main factors that affect the quality ofhydro-ecosystems of large-scale irrigation district in semi-arid regions, comprehensiveevaluation index system for quality of hydro-ecosystems of large-scale irrigation district insemi-arid regions is built. And based on existing laws and regulations, part of research resultsfor water resources, ecology, environment, etc. of the western semi-arid regions are integrated,combined with the reality of Jinghuiqu Irrigation District, evaluation criteria ofhydro-ecosystems quality are defined. These evaluation criteria are suitable for sustainabledevelopment of hydro-ecosystems in this irrigation district.(7) Based on the composite optimization method and model established in this paper, thequality of hydro-ecosystems of Jinghuiqu Irrigation District at year of2000,2005and2010are evaluated and analyzed comprehensively, and countermeasures and suggestions are putforward. |
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