Tidal as Controlling Variable of Sediment Transport Material in Tondano River Estuary

The strategic position Tondano river estuary crossing and becoming a source of drinking water the city of Manado, facing serious environmental problems with the destruction of the river mouth buffer facilities and residential population every major flooding. Studies and analyzes important as the basic policy management, resource utilization based estuarine environment. The spatial model the flow pattern and distribution of material transport in estuaries Tondano (Kuala dungarees) becomes necessary to simultaneously mapping the pattern of flow velocity and dissemination of material transport along the estuary in various seasons under the control of the tides. The study was conducted during the rainy season. Measurement of physical variables (flow rate and sample transport material) was conducted on 16 point position along the estuary of the river, each measuring point according to the position set out six segments according to the width of the river. Measurements performed on variable speed water depth of 0.2 point. Sampling was carried out at a depth of material transport close to the bottom of the river (depth 0.4 to 0.6 cm). Analysis of the physical variable data flow rate and sample transport material along the estuary using the method of spatial overlaying (overlay) which is the process of combining the spatial data to produce a map of the flow patterns and deployment models based transport material hydrophysist. In the rainy season the condition of the flow velocity changes during low tide in contrast to the current state of the tide, the flow velocity model map changes in both conditions were different shows during low tide flow rate greater than the flow rate at high tide. Changes in flow velocity at low tide to have a gradient lower than the current tide. Increased height of the tide causes an increase in flow velocity gradient changes, so that the position of the point of zero flow velocity will be shifted upstream. The results of data modeling material transport conditions and the tide low tide shows the change in material transport function along the estuary decreases, meaning that changes in transport material decreases with decreasing gradient according to the distance along the estuary. The relative sizes of transport material prices during low tide and high tide shows that transport material when the tide had smaller price decline, but the slope is greater than the material transport at low tide. Analysis of critical thresholds transport material deposition during low tide shows, along the model to near shore areas Tondano river estuary area deposition of material transport is dominated by the suspended load and wash load), when the tide turns toward the deposition position toward downstream. The deployment process and deposition of material transport along the estuary of the tondano river lasts taken control of the flow of physical variables, seasons and tides.