Evaluation of Sustainability in Sarab Seydali Watershed, Selseleh City

Evaluating the sustainability of watersheds is important since it reveals the change in the status of ecosystems in spatial and temporal dimensions. Regarding this importance, current research focuses on sustainability in Sarab Seydali Watershed located in Lorestan province, Iran. For this reason, the Watershed Sustainability Index (WSI) and the conceptual framework of HELP, whose criteria are based on hydrology, environment, life and policy, were applied. Considering different variables such as water availability and its changes, acidity and electrical conductivity of water, development of sewage systems, environmental pressure index, vegetation cover, expansion of protected areas, net annual income, human development index and its related changes, level and progress of education, study and implementation of comprehensive water resource and watershed management plans and emphasis on an interactive and logical relationship with the indicators of pressure (P), state (S) and response (R), the sustainability level of the study area was evaluated . The average scores of pressure, state and response indices were estimated as 0.81, 0.6 and 0.37, respectively. Also, the average scores of hydrology, environment, life and policy criteria were 0.41, 0.58, 0.66 and 0.75, respectively. The results of index evaluation pressure, state and response showed that the watershed's stability score with a value of 0.6 is in the medium level of stability, that the two factors of hydrology and environment cause a weak level of stability, to improve and improve the stability. It is necessary to think of measures for water resources from increasing productivity, saving and building sewage systems and habitat management through extensive management of areas focusing on pressure, state and response indicators.
 
Extended Abstract
1-Introduction
Studying the sustainability of watersheds is important because it examines all the natural, economic and social aspects of a watershed in a comprehensive and integrated manner and identifies the weak and strong points of the watershed in order to manage it. Therefore, it is necessary for decision-makers and managers to identify the factors affecting the sustainability and change of the status of each factor or criterion at the watershed level in terms of space and time. The watershed sustainability is considered necessary for both the inhabitants of the watershed and for the stability of life in ecosystems, however, this issue has not been given enough attention. One of the watershed sustainability assessment methods is the watershed sustainability index (WSI), which evaluates the sustainability of watersheds with hydrological, environmental, life and policy criteria of the HELP conceptual framework, with an emphasis on response, state and pressure indicators.
2-Materials and Methods
In this study, the Sarab Seydali Watershed located in the north of Lorestan province was selected as the study area. Using the WSI index and HELP conceptual framework criteria, aspects of hydrology (quantitative and qualitative), environment, life and policy and variables such as water availability and its changes, acidity and electrical conductivity of water, development of sewage systems, environmental pressure index, vegetation, expansion of protected areas, net annual income, human development index and its related changes, level and progress of education, study and implementation of comprehensive water resources and watershed management plans, points are assigned from zero to one to three indicators of pressure, state and response, in the form of a matrix design. Then, based on the average scores, which are numerical values ​​between zero and one, the level of watershed sustainability is defined based on the WSI index in three categories of low, medium and high sustainability.
3- Results and Discussion
The analysis of the pressure index obtained from the results of the assessment of hydrology, environment, life and policy criteria showed that the lowest score for the criterion of hydrology (quantitative and qualitative) with a score of 0.5, and the highest score is for the life and policy criterion with a score of 1. Also, the average scores for four criteria in the pressure index were calculated as 0.81. In examining the state index, it was found that the lowest and highest values were ​​for the policy and environment criteria as 0.25 and 1, respectively, and the average state index score of 0.62 indicates moderate sustainability. For the response index, the hydrology and environment criterion have the lowest score, i.e., zero, the policy criterion has the highest score, i.e., 1, and the average score of this index for all criteria is 0.37. The sustainability index of Sarab Seydali watershed was estimated 0.6. The average scores of the three indicators of pressure, state and response for the criteria of hydrology (quantitative and qualitative), environment, life and policy are 0.41, 0.58, 0.66 and 0.75, respectively. In order to overcome the weaknesses of sustainability, it is necessary to improve the hydrology criterion in the pressure index, the policy and life criterion in the state index, and the hydrology and environment criterion in the response index. In general, it can be said that the two criteria of hydrology (quantitative and qualitative) and environment are in poor sustainability, the most important reason of which is the lack of financial resources to improve the response index.
 4- Conclusion
In the Sarab Seydali watershed from the past to the year 2015 year, the annual average discharge has decreased by 1.1 cubic meters per second, which has made challenges on the water availability, so it is necessary to consider water rights and protection. The need to pay attention to construct the sewage network in this watershed, on the one hand protects water resources from pollution, and on the other hand provides the optimal use of purified and recycled water for non-drinking purposes. In general, the watershed sustainability index (WSI) using the HELP model can provide managers and experts a rational and efficient understanding and attitude by using simple and effective criteria so that they can plan and manage watersheds comprehensively and do in line with the sustainability of watersheds.