Air-water gas transport is an important process for industrial applications, such as algae production, and influences greenhouse gas emissions from or uptake into water bodies. Parameterizing and efficiently enhancing air-water gas transfer can advance sustainable energy and food technology by reducing the costs of large-scale algae production. Physical properties of the water-side scalar concentration boundary layer beneath an air-water interface determine the air-water transfer rate of weakly water-soluble gases, such as carbon dioxide (CO2) and oxygen (O2). These physical properties depend greatly on water surface deformation and water-side near surface motions. Parameterizations, based on metrics from surface particle image velocimetry (SPIV) and an acoustic Doppler velocimeter (ADV), for gas transfer velocity were compared to direct reaeration rate measurements, in the presence of complicated upwelling regions caused by longitudinal bed ridges which have been shown to increase gas transfer velocity by 9-15%. Estimates of gas transfer from ADV measurements were reasonable, with root mean square error values of 1.6-1.8 cm/h for the three models considered. The model based on the structure function of SPIV data best predicted gas transfer in the case with no bed ridges. The surface divergence, spectral, and structure function methods were similarly accurate for the case with bed ridges. Both ADV and SPIV data reveal significant lateral variation in gas transfer velocity in the presence of longitudinal bed ridges. The empirical constant in the small eddy model also varies across methods and flow cases. We further explore air-water gas transfer parameterizations in wavy flows. Specifically, we measure the impact of small (capillary-gravity) waves isolated from wind on a larger scale than previous gas transfer experiments without wind. An array of 3.2-mm-diameter, cylindrical, acrylic dowels was suspended above a 0.6-m-wide recirculating flume to penetrate the water surface by 1-2 cm and generate capillary-gravity bow waves. High flow speeds introduce additional turbulence due to boundary layer shear and inlet and outlet conditions. To achieve higher relative velocities and isolate the impact of relative dowel speed from the background flow speed, which induces boundary layer turbulence, a conveyor belt apparatus on which the dowels could be mounted was constructed. Velocity is measured using a Venturi flow meter and acoustic Doppler velocimeter. Dissolved oxygen reaeration experiments with static dowels, moving dowels, and no dowels were compared. A model to predict gas transfer enhancement due to these waves as a function of flow conditions is proposed. The gas transfer velocity at 60-cm/s flow speed was 68% higher when static dowels were present. The gas transfer velocity at 5-cm/s flow speed was 607% higher when dowels moving upstream at 64 cm/s were present. The maximum gas transfer velocity was 43.9 cm/h (equivalent to 40.4 cm/h for CO2). The models we identified or developed and the gas transfer enhancement achievements can inform the development of sustainable technologies for carbon sequestration or accessible, sustainable energy and food production. These hydrodynamic enhancements of air-water gas transfer rate can be combined with chemical enhancements to reduce capital and energy costs and net CO2 emissions of large-scale algae production as well as potentially eliminate the need to site algae pond facilities near sources of concentrated CO2.