The　rapid,　up-to-date,　cost-effective　acquisition　and　tracking　of　intertidal　topography　are　the　fundamental　basis　for　timely,　high-priority　protection　and　restoration　of　the　intertidal　zone.　The　low　cost,　ease　of　use,　and　flexible　UAV-based　photogrammetry　have　revolutionized　the　monitoring　of　intertidal　zones.　However,　the　capability　of　the　RTK-assisted　UAV　photogrammetry　without　ground　control　points,　the　impact　of　flight　configuration　difference,　the　presence　of　surface　water　in　low-lying　intertidal　areas　on　the　photogrammetric　accuracy,　and　the　potential　of　UAV/satellite　Synergy　remain　unknown.　In　this　paper,　we　used　an　RTK-assisted　UAV　to　assess　the　impact　of　the　above-mentioned　considerations　quantitatively　on　photogrammetric　results　in　the　context　of　annual　monitoring　of　the　Chongming　Dongtan　Nature　Reserve,　China　based　on　an　optimal　flight　combination.　The　results　suggested　that　(1)　RTK-assisted　UAVs　can　obtain　high-accuracy　topographic　data　with　a　vertical　RMSE　of　3.1　cm,　without　the　need　for　ground　control　points.　(2)　The　effect　of　flight　altitude　on　topographic　accuracy　was　most　significant　and　also　nonlinear.　(3)　The　elevation　obtained　by　UAV　photogrammetry　was　overestimated　by　approximately　2.4　cm　in　the　low-lying　water-bearing　regions.　(4)　The　integration　of　UAV　and　satellite　observations　can　increase　the　accuracy　of　satellite-based　waterline　methods　by　51%.　These　quantitative　results　not　only　provide　scientific　insights　and　guidelines　for　the　balance　between　accuracy　and　efficiency　in　utilizing　UAV-based　intertidal　monitoring,　but　also　demonstrate　the　great　potential　of　combined　UAV　and　satellite　observations　in　identifying　coastal　erosion　hotspots.　This　establishes　high-priority　protection　mechanisms　and　promotes　coastal　restoration.　©　2023　by　the　authors.