Nonsuspended sediment transport (NST) refers to the sediment transport regime in which the flow turbulence is unable to support the weight of transported grains. It occurs in fluvial environments (i.e., driven by a stream of liquid) and in aeolian environments (i.e., wind‐blown) and plays a key role in shaping sedimentary landscapes of planetary bodies. NST is a highly fluctuating physical process because of turbulence, surface inhomogeneities, and variations of grain size and shape and packing geometry. Furthermore, the energy of transported grains varies strongly due to variations of their flow exposure duration since their entrainment from the bed. In spite of such variability, we here propose a deterministic model that represents the entire grain motion, including grains that roll and/or slide along the bed, by a periodic saltation motion with rebound laws that describe an average rebound of a grain after colliding with the bed. The model simultaneously captures laboratory and field measurements and discrete element method (DEM)‐based numerical simulations of the threshold and rate of equilibrium NST within a factor of about 2, unifying weak and intense transport conditions in oil, water, and air (oil only for threshold). The model parameters have not been adjusted to these measurements but determined from independent data sets. Recent DEM‐based numerical simulations (Comola, Gaume, et al., 2019; https://doi.org/10.1029/2019GL082195) suggest that equilibrium aeolian NST on Earth is insensitive to the strength of cohesive bonds between bed grains. Consistently, the model captures cohesive windblown sand and windblown snow conditions despite not explicitly accounting for cohesion.

Jakarta city has been vulnerable to sea level rise and flooding for many years. A Giant Seawall (GSW) was proposed in Jakarta Bay to protect the city. The impacts of sea level rise and river discharge on the tidal dynamics in Jakarta Bay and flooding areas in Jakarta city were investigated using the finite-volume coastal ocean model (FVCOM). Model results showed that the bay is diurnally dominated by the K1 tidal component. The diurnal tides propagate westward, while the semidiurnal tides propagate eastward in the bay. The rise of sea level increases the diurnal tidal component and the inundation areas due to the increased tidal forcing: when considering a sea level rise of 0.6 m, the K1 amplitude increases by ~1% (0.25 cm) near the coastline and the current magnitude increases by 16.6% (0.05 m/s). The inundation area increases with the sea level rise in the low land elevation areas occurring near the coastlines: the inundation area increased by 29.68 km² (7.1%) with a sea level rise of 0.6 m. The increase of river discharge amplified the diurnal tidal component as well as the inundation areas at the river mouth due to increased fluvial forcing: if 10 times the mean river discharge occurs, the K1 amplitude increases by ~1% (0.25 cm) and the current magnitude increases by 100% (0.4 m/s), and the inundation areas increase by 26.61 km² (6.2%). The K1 tidal phase remains almost unchanged under both the sea level rise and river discharge conditions. The combined increase of sea level rise and the river discharge amplifies the inundation areas and the tidal currents due to increased tidal and fluvial forcing. The construction of GSW would decrease the tidal prism and dissipation effects of the bay, thus slightly increasing the K1 amplitude of the tidal level: by less than 1% (0.2 cm). There would be no significant change of phase lag for the K1 component. Although this study is site specific, the findings could be applied more widely to any open-type bays.

In ocean engineering and coastal environmental studies, local scour around a submerged structure is a typical issue, which is affected by the inclination of the structure. To investigate the effect of inclination directions and angles on flow structure and the bed morphology, a three-dimensional numerical model of a submerged inclined cylinder was established. In this model, the hydrodynamics are solved from the RANS (Reynolds-averaged Navier–Stokes) equations closed with the RNG k-ε turbulence model, while the bed morphology evolution is captured by the sediment transport model. In the case of vertical-cylinder scour, the simulation results agree well with existing laboratory experiments. In the cases of inclined-cylinder scour, the results show that the inclination direction not only changes the intensity and the location of the downflow but also modulates the pattern of the horseshoe vortex in front of the cylinder, thus influencing the local scour depth and the morphology of the bed. Compared with the case of vertical cylinder, the scour around an upstream-inclined cylinder is deeper, mainly due to the enhancement of downflow in front of the cylinder. The scour around a downstream-inclined cylinder is shallower and broader due to the weakened downflow and accelerated incoming flow. The maximum scour depth decreases with the inclination angle in the downstream-inclination case. In the upstream-inclination case, the maximum scour depth does not vary monotonously with the inclination angle, which results from a competitive effect of the horseshoe vortex and downflow in the front of the cylinder.