Tidal　channels　(TCs)　are　geomorphological　features　of　coastal　and　tidal　landscapes.　They　provide　a　pathway　for　the　exchange　of　material　and　energy　between　marshes　and　adjacent　water　bodies　and　thereby　control　the　hydrodynamic,　morphological,　and　ecological　processes　on　marsh　platforms.　Due　to　difficulties　in　terms　of　accessibility,　limitations　on　the　duration　of　exposure　during　low-water　stages,　and　variations　in　morphology　over　time,　rapid　and　accurate　mapping　of　such　intertidal　morphological　features　at　a　high　frequency　is　extremely　challenging.　Here,　we　present　an　efficient　method　integrated　unmanned　aerial　vehicles　(UAVs)　structure-from-motion　(SfM)　photogrammetry,　and　spatial　morphological　fitting　and　delineation　for　accurately　quantifying　channel　three-dimensional　(3D)　morphological　features　in　terms　width,　depth,　width-to-depth　ratio,　and　cross-sectional　area.　We　also　relate　these　measured　proxies　to　salt　marsh　species　distributions.　A　two-step　thresholding　approach　combining　elevation　and　slope　is　developed　in　order　to　determinate　TC　boundaries　from　salt　marsh　and　tidal　flat　area,　and　a　Gaussian　fit　is　used　to　estimate　water-bearing　channel　depth　and　cross-sectional　area.　Salt　marsh　species　are　identified　from　fine-resolution　multispectral　satellite　data　and　a　field　training　dataset　using　a　Random　Forest　classifier.　Our　results　indicate　that　(1)　UAV-based　SfM　photogrammetry　can　achieve　centimeter-level　accuracy　in　mapping　the　topography　of　TCs,　with　a　root　mean　square　error　(RMSE)　of　5.7　cm　—　mainly　from　the　strong　reflection　of　light　from　smooth　TC　water　surfaces　and　the　presence　of　water-bearing　layers;　(2)　the　morphological　features　of　TCs,　ranging　from　tidal　flats　to　salt　marsh　areas,　demonstrate　a　similar　tendency,　which　increases　at　first　and　then　decreases.　The　maximum　depth　and　cross-sectional　area　of　TCs　is　in　sparse　salt-marsh　area,　up　to　4　m　and　150　m2,　respectively;　and　(3)　TC　morphology　has　a　major　impact　on　the　distribution　of　salt　marsh　plants　and　such　effects　vary　across　different　plant　species.　These　results　greatly　contribute　deep　understanding　of　feedbacks　between　TCs　and　salt　marsh　plant　species　distribution　and　have　significant　implications　for　developing　ecological　and　morphological　salt　marsh　restoration　guidelines.　©　2022　Elsevier　B.V.