Materials and Method

Aghanashini is a west flowing river with catchment area of 1450.9 sq.km (Fig. 1), spread across the districts of Uttara Kannada (Ankola, Kumta, Sirsi, Honavar, Siddapur) and portions of Shimoga (Sorab). The Aghanashini river originates in Sirsi taluk, Uttara Kannada district. The river has two sources – Bakurholé tributary (at Manjguni) and Donihalla (near Sirsi) which meets at Mutthalli (Balachandran et al. 2012; Ramachandra et al. 2015). Aghanashini river estuary has dense and diverse mangrove forests along the coast. Rainfall across the basins varies from as low as 3000 mm at the plains of Sirsi and to as high as over 5000 mm at the Ghats. Temperature in the basins varies from as low as 15.3℃ in January to as high as 35.4℃ in April. Elevation in the catchment varies between less than 0 meters to 786 m of Mean sea level (Ramachandra et al. 2016b). In the current study, Chandikahole’s sub catchments were considered for assessment of flow. Chandikaholé originated at Yaana and joins Aghanashini at Uppinapattana. About 8 macro and micro watersheds were considered taking into account i) similar climatic conditions (about 3500 mm rainfall), ii) all the micro watersheds connect to a macro watershed, iii) variability in landscape, etc.
Yaana, Nanalli, Beilangi, Mastihalla, Harita are the micro watersheds connecting Aanegundi (AGT1), whereas Aanegundi (AGT1 and AGT2), and Bialgadde (BGT) are the macro watersheds. Aanegundi AGT1 and AGT2 join near Yaana cross along the Sirsi-Kumta Road. The descriptions of various micro/macro watersheds sampled are given in Table 1. Yaana and Nanalli catchments are dominated by evergreen forests, followed by Beilangi which consists of moist deciduous forests and evergreen forests whereas, rest of the catchment areas have mixed land use dominated by horticulture and agriculture activities.