RESUMEN
In this study, with water salinity as the core index, sea-land hydrological connectivity index was constructed by integrating the hydrological structure connectivity index (water surface ratio, intake and outtake density, sea-land distance, and ditch distance). Based on multi-scale spatial analysis, we carried out the spatial quantitative analysis and classification of sea-land hydrological connectivity in the study area under an evaluation unit of 150 m×150 m grid. The results showed that sea-land hydrological connectivity gradually decreased from sea to land, with different decreasing rates. The spatial differentiation of water salinity in the study area was substantial, with certain impacts on the change rate of hydrological connectivity. The sea-land hydrological connectivity was divided into four grades, which was excellent, good, medium, and poor. The areas under excellent and good grades were mainly distributed in offshore areas, with saltwater aquaculture ponds and farmland as the main land use types. The regions with moderate and poor land use were mainly distributed in inland areas, with freshwater aquaculture ponds and farmland as the land use types. The hydrological process of coastal wetlands was complex. Quantitative coastal wetland hydrological connectivity could provide reference for coastal wetland status assessment and wetland restoration.
Asunto(s)
Salinidad , Humedales , Agua Dulce , Hidrología , AguaRESUMEN
Hydrological conditions in the plains irrigation area are complex, which are strongly affected by small irrigation facilities and human management. In this study, the connectivity index of ditch network and the influence index of rural small irrigation facilities were constructed to quantitatively analyze the hydrological connectivity of a typical plain irrigation area, Fudong irrigation area, in north Jiangsu Province. The self-organizing feature map (SOM) analysis method was used to identify the effects of small irrigation facilities on the spatial heterogeneity of ditch network structure connectivity. The results showed that the hydrological structure connectivity differed in different regions of Fudong. The connectivity in the north of the irrigation area was the best, but the worst in the central and southern part of the irrigation area. There were 876 pumps, 633 gates and 2420 culverts in the study area. Without the effects of small irrigation facilities, there were 13 villages with poor hydrological structure connectivity and 48 villages with good and best hydrological structure connectivity. Under the effects of small irrigation facilities, the number of villages with poor connectivity was reduced to 8, while the number of villages with good and best connectivity was increased to 53. Due to the influence of gates and culvert, the hydrological connectivity of 26 villages in Fudong became poor. The hydrological connectivity of 39 villages had been enhanced due to the existence of pump.
