Use of Landsat is of importance in monitoring and assessment of long-term changes of water quality in freshwater ecosystems, especially in small water bodies. In this study, over a 32-year period (1985–2017), the changes in water surface temperature (WST), secchi disk transparency (SDT), and chlorophyll-a (Chl-a) concentration were estimated at the Choghakhor wetland using Landsat imagery. Based on WST three detectable temperature zones can be observed within the wetland aquatic environment where the highest amount was observed in thermal strips. The results showed Chl-a concentration volatility in different periods in the wetland as well as its long-term increasing trend. The western part of the wetland, as compared to other areas, was affected by these changes, which could be due to the human activity concentrated in this area. In contrast (SDT) showed a decreasing trend during this period that was consistent with the observed changes in Chl-a concentration. This could be due to an increase in organic matter load and suspended solids in the water body of wetland during this time. Comparison of the extracted satellite data with the field data showed the least RMSE and high R2. Also, ANOVA results showed significant spatio-temporal differences between the studied parameters in Choghakhor wetland (p < 0.05). The present study can help to detect long-term changes in Choghakhor wetland and help toward moving to optimal management and protection of this wetland.
Water resource management has numerous environmental challenges, especially in aquatic ecosystems such as rivers due to the heterogeneous distribution of surface water resources, among other diverse impacting factors. In Iran (one of the countries of the Middle-East), population growth, development of urban communities and development of agricultural and industrial activities provide additional impacts on the functioning of aquatic ecosystems. The United Nations declared the third decade of this century (2021–2030) as the decade of ecosystem restoration. In this study, we have selected the Zayandehroud River as a case study and then evaluated the pathology of existing statuses. Strategies and approaches were studied and analyzed including the need to utilize integrated water resources management (IWRM), approaches for dealing with drought conditions, payment of water rights and dam alternatives, and the need for ecological landscape studies. Then, strategies and approaches appropriate from the perspective of restoration were identified, including the techniques used, and the experiences of different countries. The analysis showed that similar regions of Iran in the Middle-East need to change the paradigm of "nature control" to the paradigm of "nature management" and reduce reliance on structural and technological solutions in water resources management.
One of the challenges for managers is to ensure the long‐term sustainability of wetlands by protecting their ecological values against natural and human pressures. This study has evaluated the past vulnerability status of Gavkhooni International Wetland, Isfahan, Iran, using a combination of GIS and multicriteria spatial decision support systems (MC‐SDSS) processes, to propose restoration scenarios. Three scenarios were developed from criteria established using field studies and expert opinion: (1) wetland restoration to preserve existing water bodies, (2) determination of susceptible regions as habitat replacement for aquatic communities, and (3) a combination of the two previous scenarios. Finally, a map was developed classifying the regions into five categories by area of priority. The northern regions of the wetland were prioritized based on the results of the first and the second scenarios. The third scenario provided the highest opportunity to obtain an optimistic state, that is, normal conditions, for the wetland marginal regions, especially in the central region (between the east and west). In a pessimistic state and optimistic state of the third scenario, almost all parts of the center to the south of the wetland show the lowest priority restoration scenarios. According to the different scenarios, the central regions of the wetland are less affected by agricultural activities and human settlements. In general, the results show that the Gavkhooni Wetland is unstable based on functional, environmental, social and economic conditions. According to the criteria and the MC‐SDSS model, the government can adopt and implement the necessary policies and programs to improve the condition of the wetland.
In this study, the environmental monitoring of Anzali international wetland (based on water surface temperature (WST), chlorophyll-a (Chl-a) and transparency (secchi disk depth (SDD)) parameters) using Landsat images in the period 1985-2018 has been studied. Based on the results of zoning maps, in 2018 and 2013, WST fluctuations are higher, with the lowest water temperature observed in 2007.Based on Chl-a, the trend for this parameter is increasing from 1985 to 2018. Also, from 1985 to 2018, we saw a decrease in transparency (SDD), which could indicate an increase in opacity and concentration of suspended and organic particles in the wetland, which was consistent with the results of chlorophyll-a. Graph examination of wetland showed more changes belonged to the central and eastern parts of the wetland. The results of this study indicate that in the Anzali international wetland, comparing the values of the parameters studied, there are not good conditions for water quality and the need for a solution and management policies to improve the condition of this unique ecosystem is necessary more than ever.
As of natural constraints, and the specific climate of Iran, as well as the increasing importance of international water resources in the socio‐economic development of societies, studies on surface water resources, especially wetlands, merit special attention. Accordingly, the TM, ETM+ and OLI satellite images of 1985, 2000 and 2018 were used in the present study to detect changes in the Choghakhor international wetland. Classifying the images with a supervised method, and using maximum likelihood algorithms, the distinct land use/land cover classes of waterbody, aquatic plants, pasture and forest, agricultural lands, bare land and human built lands were ranked. Selected landscape metrics information on the spatial pattern of the Choghakhor wetland was quantitatively determined, using Fragstats software, and the spatial composition and vulnerability of the wetland were evaluated. The vulnerability assessment of wetland contamination was investigated using the WRASTIC index based on the catchment area scale. Time processing of the data obtained from the maps indicated a 26.63% decrease in the pasture and forest area, and a 12.1% increase in the area of human built lands and agriculture lands during the period from 1985 to 2018. Further, in spite of the waterbody area expanding during 1985 to 2000, it subsequently shrunk in size from 2000 to 2018, with the area of aquatic plants lands increasing during the same period. Analysis of landscape metrics generally indicated the natural wetland cover has been changing during this period along with increasing anthropogenic impacts. Degradation, rotation and replacement of natural land cover such as pastures and forests with human built areas can be considered undesirable development effects on the Choghakhor wetland. The results of the WRASTIC index calculation indicated a major impact of Choghakhor wetland components from water pollution. The results of the present study place an emphasis on more sustainable land use and prevention of land destruction in the Choghakhor wetland basin.
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