Human　activities,　particularly　reservoir　construction,　have　become　a　focal　point　in　contemporary　earth　science　research　due　to　their　profound　impacts　on　flow-sediment-ecology　systems　of　catchment.　While　some　investigations　have　examined　reservoir-induced　alterations　in　fluvial-estuarine　sedimentation　patterns,　the　feedback　mechanisms　between　morphological　changes　and　tidal　dynamics　remain　inadequately　explored.　This　research　focuses　on　the　Minjiang　River　estuary,　a　macrotidal　system　in　southeastern　China,　characterized　as　a　medium-scale　catchment　(length:　562　km;　drainage　area:　60,000　km2).　Employing　an　integrated　approach　combining　field　hydrographic　measurements,　multi-temporal　digital　elevation　models,　and　Mike21　simulations,　this　study　quantifies　the　decadal-scale　interplay　between　anthropogenic-driven　geomorphic　evolution　and　tidal　system　adjustments　over　a　40-year　period　(1984–2022).　The　analysis　reveals　that　reservoir　operations　and　river　sand　mining　have　transformed　the　estuarine　sedimentary　regime　from　net　deposition　(0.4　cm/year,　1984–2005)　to　accelerated　erosion　(−2.6　cm/year,　2005–2022).　This　geomorphic　transition　has　triggered　significant　hydrodynamic　responses.　During　the　deposition-dominated　phase　(1984–2005),　sediment　accumulation　resulted　in　a　progressive　decline　of　1.5　cm　in　the　mean　tidal　levels　and　a　6.5　cm/s　reduction　in　flow　velocities.　Conversely,　the　subsequent　erosional　period　(2005–2022)　saw　a　2.2　cm　rise　in　tidal　levels　accompanied　by　a　9.3　cm/s　acceleration　in　flow　velocities.　The　flow　and　sediment　flux　during　flood　and　ebb　periods　in　estuarine　branches　such　as　North　Branch　increased　by　53　%　and　57　%,　respectively.　Furthermore,　the　bed　dunes　in　Maiwei　and　North　Branch　increased　by　0.3m　(13　%)　and　0.1　m　(8　%),　respectively.　This　research　establishes　a　fundamental　principle　of　sediment　dynamics:　depositional　processes　attenuate　tidal　energy　while　erosional　regimes　enhance　hydrodynamics.　These　findings　provide　critical　insights　into　the　cascading　effects　of　human　activities　at　the　catchment　scale　on　coastal　hydro-morphological　systems,　offering　a　scientific　framework　for　sustainable　estuarine　management　under　increasing　anthropogenic　pressures.　©　2025　Elsevier　Ltd