Study　region:　Zhaotong　City,　located　in　the　Jinsha　River　Watershed　in　southwest　China,　features　a　developed　river　network,　mountainous　terrain,　and　significant　elevation　changes.　The　region　experiences　a　low-latitude　plateau　monsoon　climate,　with　rainfall　concentrated　in　the　wet　season.　Study　focus:　This　study　uses　a　2D　hydrodynamic　model　and　a　dam-break　flood　model　to　assess　flood　risks　of　parallel　reservoirs　and　quantify　direct　economic　losses　under　different　scenarios.　It　also　explores　the　causes　of　risk　and　loss　variations　across　scenarios.　New　hydrological　insights　for　the　region:　Differences　in　dam　site　locations　and　downstream　topography　result　in　significant　variations　in　inundation　areas,　with　extreme　cases　differing　by　nearly　twofold.　Dam-break　flood　losses　depend　on　inundation　extent,　water　depth,　and　land　value.　Variations　in　high-value　land　inundation,　such　as　residential,　commercial,　and　industrial　areas,　are　the　main　reason　for　differences　in　direct　economic　losses.　The　fatality　area　of　a　dam-break　flood　from　parallel　reservoirs　is　smaller　than　the　sum　of　individual　reservoirs　due　to　river　confluence　effects,　delaying　the　flood＇s　arrival　at　the　city　center.　Overall,　parallel　reservoir　dam-break　risks　are　influenced　by　multiple　factors,　requiring　case-specific　analysis　rather　than　simple　risk　summation.　©　2025　The　Authors