This　study　presents　an　analytical　solution　for　coupled　water-gas　transport　in　a　landfill　cover　system　considering　four　different　root　architectures　(i.e.,　uniform,　triangular,　exponential　and　parabolic　architectures),　which　can　consider　transient　diffusive-advective　transport　of　gas　under　steady-state　water　distributions　in　different　con-dition　(e.g.,　rainfall　stage　and　evaporation　stage).　The　proposed　solution　is　verified　against　an　existing　analytical　solution,　validated　against　an　experiment,　and　compared　with　a　numerical　solution.　Using　the　verified　analytical　solution,　simulations　were　conducted　on　the　coupled　water-gas　transport.　The　results　show　that　ignoring　water　transport　can　lead　to　significant　error　in　gas　transport　results　under　various　conditions　(e.g.,　the　methane　flux　is　underestimated　by　45%　due　to　ignoring　water　transport,　when　the　desaturation　coefficient　alpha　is　0.1　m1).　The　parametric　study　results　indicate　that　triangular　and　exponential　root　architectures　have　greater　effect　on　water-gas　transport　(e.g.,　pore-water　pressure,　gas　emission　fluxes)　compared　with　the　uniform　and　parabolic　root　architectures;　vegetation　has　a　significant　impact　on　the　water-gas　transport,　especially　in　dry　conditions　(e.　g.,　the　gas　emission　flux　through　vegetated　cover　is　about　26.3%　lower　than　that　through　the　bare　cover);　the　rainfall　intensity　and　volumetric　water　content　at　the　bottom　boundary　have　significant　effect　on　water-gas　transport　in　the　cover.　The　proposed　analytical　solution　can　be　used　to　aid　the　design　of　vegetated　soil　cover　system　and　the　verification　of　other　more　complex　models