# The Travel Time of Floatable Litter of Different Densities Influenced by River Flow Velocity
## 3 Results and Discussion
### The Floatable Litter Travel Time with Different River Flow Velocity
\begin{table}
\begin{tabular}{c c c c} \hline \hline
**FL Code** & **Travel Time A (s)** & **Travel Time B (s)** & **Travel Time C (s)** \\ \hline FL1 & 47.87 & 98.2 & 88.79 \\ FL2 & 56.08 & 87.58 & 101.06 \\ FL3 & 47.33 & 87.32 & 94.8 \\ FL4 & 49.98 & 75 & 89.58 \\ FL5 & 51.08 & 82.92 & 89.58 \\ FL6 & 50.18 & 122.01 & 94.08 \\ FL7 & 50.45 & 108.12 & 101.08 \\ FL8 & 46.5 & 115.18 & 62.11 \\ FL9 & 82 & 204.9 & 186.75 \\ FL10 & 69 & 94.17 & 65.28 \\ FL11 & 51.07 & 89.64 & 73.05 \\ FL12 & 45.69 & 97.95 & 87.08 \\ FL13 & 48.33 & 104.16 & 83.08 \\ FL14 & 43.93 & 105.1 & 57.65 \\ FL15 & 50.05 & 92.76 & 74.94 \\ FL16 & 46.35 & 80.31 & 58.79 \\ FL17 & 47.74 & 71.95 & 80.5 \\ FL18 & 50.94 & 76.82 & 76.84 \\ FL19 & 47.69 & 78.79 & 78.13 \\ FL20 & 47.29 & 78.25 & 62.85 \\ \hline \hline \end{tabular}
\end{table} 
Table 4: The list of FL travel times during each condition. Figure 7: The travel time for different densities of FL for three river flow velocity conditions. (i.e., air-filled containers such as PET bottles or low-density expanded polystyrene (EPS)) to move faster and further and have a higher tendency to accumulate at the riverside and coastal areas. In Condition C, all FL travel times are longer than Condition A except for the cardboard box (FL10). The FL travel time of Condition C is compared to Condition A because the different patterns of FL travel time can be observed significantly between these two conditions, where the travel time increases with the increase in river flow velocity. However, the increase in the FL density value does not determine the increase in FL travel time specifically. The FL travel time is highly distributed with the increase in density value. For FL10, its travel time is shorter, T = 65.28 s, than in Condition A, T = 69.00 s. Wind factors can influence the travel time of FL10 to be the shortest during Condition C compared to other conditions because FL10 was seen to be dispersed quite far from the displacement between Point A and Point B due to the sudden occurrence of turbulence. The travel time of the crisp packet (FL6) with density \(\rho\) = 91.400 kg/m\({}^{3}\) is longer than many other FLs with a higher density range, \(\rho\) = 92.400-91.620 kg/m\({}^{3}\), in all conditions. The FL6 travel time, T = 122.01 s, is the second longest after the FL9 travel time, T = 204.90 s, during Condition B. Another factor that can affect the travel time of an FL despite its density is the entrance of river water into FL, especially for FL with an opening (i.e., the mouth of a bottle) and cavity. The FL term used in this study defines the solid waste being disposed into the river. Thus, most of the FL is expected to have openings because they are waste. Other than a crisp packet (FL6), the aluminum can (FL7) and cardboard box (FL10) are a few examples of FL with the possibility of water entrance. The water entrance will directly increase the FL density because the mass of FL has increased while the FL volume is constant. From the velocity formula, mass is directly proportional to density when the volume is constant. Overall, some regularities were not met (e.g., higher river flow velocity causes faster time taken for FL to migrate) due to uncontrolled conditions occurring during the on-field simulation. Moreover, most of these uncontrolled conditions are not considered to be within the scope of the present study. In summary, magazine paper (FL14) travels the fastest both in Condition A and C which are T = 43.93 s (mean \(\pm\) SD; 51.478 \(\pm\) 8.870) and T = 57.65 s (mean \(\pm\) SD; 85.30 \(\pm\) 27.46), respectively. In Condition B, the fastest FL traveled was slipper (FL17), T = 71.95 (mean \(\pm\) SD; 97.56 \(\pm\) 6.44). FL9 travels the slowest in all conditions, A, B, and C, which are T = 82.00 s, T = 204.90, and T = 186.75 s, respectively. Overall, the fastest FL traveled is magazine paper (FL14) with T = 43.93 s (mean \(\pm\) SD; 51.478 \(\pm\) 8.870) during Condition A (V = 0.230 m/s).