STUDY OF RIVER CONFLUENCES FROM UPLAND MAHARASHTRA: A CASE STUDY OF RIVER MULA

River confluences are universal feature in all fluvial systems. It has been viewed as a point of abrupt change in hydraulic geometry (Richards, 1980), discontinuity in sediment distribution (Ferguson et al. 2000), three-dimensional patterns of flow and its dynamics (Best, 1985, Biron et, al 1996) etc. From the past experiments and studies, junction angle, discharge ratio and the geology at the confluence zone has been ascertained as the convincing factors influencing the dynamics of the confluence zone. In the present study, part of the Mula basin stretch (47 km) from Lahit Khurd (19˚ 24΄00˝ N and 73 ˚ 3΄ 00˝ 00E.) upto downstream Kas Junction (19˚ 16΄ 30˝ N and 74˚ 14΄ 00˝E) is selected. The entire left bank and the right bank stream greater than third order are chosen and their morphometric characteristics calculated [SOI 1: 50,000 (47E/15, 47I/3)]. The actual ground characteristics of these confluences are observed on the field. With the information from map and field observation, 5m × 3 m concrete flume model is prepared with five left bank tributaries and one major right bank tributary. Discharge for mainstream and each tributary are varied according to their respective stream order.