Impact of estuarine processes and hydro-meteorological forcing on landform changes: a remote sensing, GIS and statistica
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ORIGINAL PAPER
Impact of estuarine processes and hydro-meteorological forcing on landform changes: a remote sensing, GIS and statistical approach B. Deepika & Kumar Avinash & Katihalli Siddappa Jayappa
Received: 28 January 2013 / Accepted: 3 January 2014 # Saudi Society for Geosciences 2014
Abstract Changes in estuarine morphology and landforms (braided islands, mudflats, barrier spits and marshy land) of Gangolli estuary, west coast of India, have been studied using topographic maps and satellite images of the last 45 years (1967–2012). The seasonal fluctuations in hydrometeorological (river discharge, runoff, rainfall, relative humidity and temperature) conditions play an important role in morphological changes of landforms. The computed results were recorded no significant relationship (p>0.050) between areal extents of the different landforms (except Is7 and Mf3) and hydro-meteorological parameters. The correlation analysis suggests that ∼65 % of the landforms show medium (r= 0.3–0.5) to high (r=0.5–1.0) strength of association between areal extent versus discharge, runoff and temperature. However, ∼80 % of the landforms show high to medium strength of association between areal extent versus rainfall and relative humidity. The study confides that gradual accumulation of sediment brought by rivers and eventually drifted into the estuary by waves and tidal currents is responsible for stabilisation and growth of the different landforms such as estuarine banks, braided islands and spits. By contrast, both natural and anthropogenic activities have played a major role B. Deepika : K. S. Jayappa (*) Department of Marine Geology, Mangalore University, Mangalagangotri 574 199, Karnataka, India e-mail: [email protected] B. Deepika e-mail: [email protected] K. Avinash Polar Remote Sensing Division, National Centre for Antarctic and Ocean Research, Ministry of Earth Sciences (MoES), Vasco-da-Gama, Goa 403 804, India e-mail: [email protected]
in dynamic changes of estuarine morphology and landforms of Gangolli estuary, but human interventions especially construction of harbour, sand mining and reclamation are the most significant factors. Keywords Anthropogenic activities . Barrier spit . Braided islands . Estuarine morphology
Introduction Coastal and estuarine areas influenced by geological, meteorological and oceanographic processes are very important for human and coastal ecosystems around the world. Estuaries are spatially and temporally dynamic transition zones influenced by numerous interacting processes such as large and small scale hydrodynamics, sediment transport dynamics, growth and decay of bed perturbations, biological processes and human interferences (Sherwood and Creager 1990; Reed et al. 2004; Cronin et al. 2007). Therefore, it is imperative to understand the processes like daily tidal cycles, seasonal and inter-annual variations in river discharge and temperature, long-term shifts in bedform and sediment distribution (Menon et al. 2006; Keefer et al. 2008). Physical processes, such as i
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