Assessment of factors affecting hydrologic variability of Wadhvana wetland, Gujarat (India)

The Wadhvana wetland, a Ramsar site, is a wintering place for migratory birds, including endangered species. The current study aimed to evaluate the variables influencing the hydrologic variability of the Wadhvana wetland through an analysis of water distribution throughout the pre- and post-monsoon seasons. The Modified Normalised Difference Water Index (MNDWI) was computed using Landsat data to estimate the water spread. The wetland’s catchment region was analyzed using SRTM Digital Elevation Model data to examine the drainage pattern and drainage basin. The results of the analysis indicate that the premonsoon water coverage area decreased significantly between 2003 and 2022. However, the postmonsoon water amount is sustained through imports from the Narmada Canal. The drastic change in the water spread may affect the wetland’s aquatic flora as in the dry season the wetland would be prone to cattle grazing or agricultural activities by nearby residents. Predominant land use in the drainage basin is the usage of land for agriculture, where water requirement is fulfilled either with groundwater drawn from tubewells or water from the Wadhvana wetland. The random survey conducted in the villages near the wetland indicates that the residents depend on the wetland for irrigation and livestock farming. The wetland and the aquifer in the basin are hydraulically connected, thus for long-term sustenance of the wetland, conservation efforts and measures would be required to improve the irrigation techniques and maximize the rainwater harvesting for groundwater recharge so that the pressure on the wetland can be minimized.