 The effect of 46,000 hectare irrigation plan of Sistan plain on spatial-spatial changes of rural environmental sustainability

Introduction    Sistan region also has special environmental characteristics due to its location in arid and desert region. Low rainfall, high temperature and evaporation, poor vegetation, dependence of the region on the Helmand River water, intermittent reduction or cessation of the annual Helmand River water and the occurrence of droughts, the presence of alluvial soil with alternating layers of sand and clay and 120-day winds and the consequent occurrence of dust and the formation of quicksands, cause fragile and sensitive environmental conditions prevail in the region. In addition, in this region, after the closure of the border and the creation of a security wall at its periphery (which practically eliminated the concrete wall, the possibility of border crossings), water played the largest role in the economic, social and political development of the region. The reason for the increase in investment in the implementation of water control and diversion projects upstream (Afghanistan) and the restriction of water entering the Sistan plain, water should be considered as a very valuable commodity. Therefore, in the circumstances that the severity of water limitation in most villages of Sistan is a serious issue, paying attention to increasing water consumption efficiency and improving its productivity will be an inevitable necessity (Asghari Lafmajani and Naderianfar, 2012). According to studies, increasing water efficiency using pressurized and semi-pressurized systems from wells and reservoirs will increase from 20% to 90% and water transfer with piping system is more economically justified than water transmission system with It has open canals (Piri et al., 2014). The region is designed to increase the economic power of the villagers with the sustainability approach. The sustainability zone has been designed in 766 villages of Sistan in the form of 2137 groups of 20 hectares of water. An overview of scientific texts related to the subject of research shows that many researches have been done in relation to environmental issues and its effects; However, no research has been done on the impact of irrigation projects on environmental sustainability and there is a gap in studies in this field. Therefore, the present study, in the framework of a systemic approach, analyzes the spatial-spatial changes of the impact of the 46,000-hectare Sistan plain irrigation project on the environmental sustainability of rural areas of Hamoon city.Results and discussionThe statistical population of the study includes 159 villages of Hamoon city with a total population of 66,675 people and 19,133 households. To achieve the desired results, villages with a population of more than 20 households were identified and then among these villages, with the opinion of social and technical experts, 40 villages in which the irrigation network was implemented and operated (10 villages in each development area) with a total population of 10150 people. And 3477 households were surveyed as sample villages. The sample size of households living in villages was determined based on Cochran's formula of 346 households, which were finally distributed according to the number of households in the sample villages of the questionnaires.Conclusion                  The study of the distribution of the studied villages in terms of the level of environmental sustainability before the implementation of the project shows that the villages with poor stability are mainly far from the wells and in low water years when the inflow of Helmand River to the region is somewhat reduced. He finds that the agricultural activities of these villages are completely stopped. Meanwhile, with the implementation of the water transfer plan to the agricultural lands of the villagers, there have been positive changes in the environmental stability of almost 30% of the villages compared to the past.