淡水河口是個河海口地帶的泥灘地，也是一個變動極大的動態環境。本研究從河口地形演化觀點探討淡水河口之紅樹林分布和地形演育及水文關係。希望能瞭解淡水河口的河口地形與水文特徵，同時瞭解這些地形特徵如何影響紅樹林的發育。 由淡水河口的相關水文與河道地形資料顯示，淡水河口是一個非常動態的河口。以淡水河河口的水位變化而言，明顯受到颱風的影響，水位的高度，從過去三十多年來的颱風洪水水位記錄表看來，瞬時最高水位可達2.6公尺左右。這樣的高度對沙洲與其上的紅樹林，造成的沖蝕現象，尤其是側蝕現象非常明顯。由航照判讀亦可看出該區段的靠河側是所謂的自然堤，而該自然堤常常因為洪水而決堤，並造成該地區的氾濫。實地觀察這些自然堤，可以發現並沒有紅樹林生長其上，主要的原因是自然堤的組成以沙粒為主，不是紅樹林所需的泥灘地。這些紅樹林分佈區的邊緣，受到洪水的影響而增減的現象明顯。 民國70年代所被破壞的紅樹林，經過的16年的復育(未經人為干擾)，已經漸漸回復原有的面貌。然而靠河側的沙洲，仍有被洪水侵蝕的問題。紅樹林也因此有被侵蝕的潛在問題。

The estuary of the Tamsui River is a dynamic environment with a mangrove ecosystem. The purpose of this study is to discuss the distribution of mangrove at the estuary of the Tamsui River and the relationships of this distribution to the morphological and hydrological characteristics. Aerial photographs and hydrological data were analysed for this purpose. According to aerial photo interpretations and typhoon period water levels from the last 30 years, there are many dramatic changes in bank erosion of sand bars, especially during high water periods. There is a relationship between the distribution of mangrove and the soil texture of the tidal f1at.There is no mangrove on the natural levee. The distribution of mangrove appears to be influenced by bank erosion, and is a potential problem for the management of the nature reserve on the estuary of the Tamsui River.