Channel Characteristics and Planform Dynamics in the Indian Terai, Sharda River

Abstract

The Sharda River creates and maintains the ecologically diverse remnant patches of rare Terai ecosystem in northern India. This study used repeat satellite imagery and geographic information system analysis to assess the planform dynamics along a 60 km length of the Sharda River between 1977 and 2001 to understand the altered dynamics and its plausible causes in this data-poor region. Analyses revealed that the Sharda River has undergone significant change corresponding to enhanced instability in terms of increased number of neck cut-offs and consistent occurrence of avulsions in subsequent shorter assessment periods. An increased channel area (8%), decreased sinuosity (15%), increased braiding intensity, and abrupt migrations were also documented. The river has migrated toward the east with its west bankline being more unstable. The maximum shifts were 2.85 km in 13 years (1977-1990), 2.33 km in next 9 years (1990-1999), and a substantial shift of 2.39 km in just 2 years (1999-2001). The altered dynamics is making the future of critical wildlife habitats in Kishanpur Wildlife Sanctuary and North Kheri Forest Division precarious and causing significant economic damage. Extensive deforestation and expansion of agriculture since the 1950s in the catchment area are presumed to have severely impacted the equilibrium of the river, which urgently needs a management plan including wildlife habitat conservation, control, and risk reduction. The present study provides a strong foundation for understanding channel changes in the Sharda River and the finding can serve as a valuable information base for effective management planning and ecological restoration.

High spatiotemporal resolution of river planform dynamics from Landsat: The RivMAP toolbox and results from the Ucayali River

“…However, the difficulty of observing multidecadal river migrations at high temporal and spatial resolutions has hampered efforts to fully resolve natural planform dynamics [ Hooke , ]. Observations made over longer periods (decades to centuries) are often compiled from various sources such as historic maps, surveys, and aerial photographs that do not capture planform changes [ Hooke and Redmond , ; Harmar and Clifford , ; Yao et al ., ] due to nonstationary flow regimes [ Bradley and Smith , ; Kiss and Blanka , ], individual floods [ Hickin and Sichingabula , ; Nagata et al ., ], cutoffs [ Hooke , ; Zinger et al ., ; Martha et al ., ], or human activities [ Asner et al ., ; Midha and Mathur , ; Słowik , ; Rhoads et al ., ]. On the other hand, studies that resolve detailed migration dynamics at event‐scale frequencies from aerial photographs are often constrained to significantly shorter durations than the inception‐to‐cutoff time of a typical meander bend [e.g., Bertoldi et al ., ].…”

Agricultural lands offer seasonal habitats to tigers in a human‐dominated and fragmented landscape in India

“…The area is subject to humid subtropical climatic conditions with four dominant seasons: summer (April–June), monsoon (July–September), post‐monsoon (October–November), and winter (December–March). During the monsoon season, substantial portions of the area experience flooding (Midha and Mathur ). Besides tigers, the CTL supports multiple species of threatened fauna including the greater one‐horned rhinoceros ( Rhinoceros unicornis ), swamp deer ( Cervus duvaucelli duvaucelli ), hog deer ( Axis porcinus ), and Asian elephants ( Elephas maximus ).…”

Geographies of India-Nepal contestation

“…The deconstruction of the map is not that simple, however. As said earlier not naming the river could be a historic correction especially when experts have identified Kalapani as the origin of the river (Midha and Mathur 2014). The correction came quite late.…”