本研究蒐集全台各河川閘門維護管理單位之相關閘門調查報告，並藉由規劃閘門現場調查方式，透過現場第一線之代操作工作人員，試記錄全台灣各地區閘門實際現況，完成水利署各河川局轄管閘門調查工作，包含：閘門尺寸、出口面向及側牆情況等，並且針對防潮閘門出口附近之淤積可能原因進行研究探討，以供後續提出可行之防砂或減砂措施參考與設計建議。
一般閘門主要淤積原因多為因漲潮造成之漂砂淤積、因地形及床砂特性造成之淤積、上游側（閘門內水）淤積、風砂堆積、植物蔓生、漂流物或雜物淤積等原因，本研究根據全台閘門現場調查之結果，將台灣分為北、中、南、東四個地區，分別說明其閘門數量、出口類型（閘門出口臨河川者後簡稱排水、河川區閘門，閘門出口臨海岸者後簡稱海堤區閘門）、淤積程度、以及淤積成因等，進一步瞭解位處不同區域之閘門其淤積原因異同處。
本研究完成相關閘門基本資料與淤積現況調查，排水、河川區閘門淤積之成因多為受附近地形及床砂特性影響(6％-25％)，亦或是渠道植物蔓生(4％-65％)；海堤區閘門淤積之成因多為因海浪漲潮將泥砂帶到海堤區閘門附近淤積(8％-27％)、受附近地形及床砂特性影響(1％-5％)、亦或是上游處常有農作物枝幹隨水流推移而造成淤積(1％-6％)，進而影響閘門正常功能。
依各河川局轄管閘門淤積成因之調查結果，研擬防潮閘門因應出口防淤減淤之規劃設計原則，排水、河川區閘門建議以機械或人工撈除及噴灑除草劑方式搭配生物防治法防治水生植物之蔓生，在閘門出口之型態上，建議側牆與閘門具交角之形式，利於泥砂運移與河道穩定；海堤區閘門在設置前建議研判當地優勢輸砂方向，以減少沿岸區域漂砂落淤於閘門口影響閘門運作，閘門出口處建議設置導流堤以攔截沿岸漂砂，減少漂砂淤積。
本研究整合相關資料，希望提供相關研究者之參考，同時建議後續閘門現場基本資料調查，可以再試增加調查項目，包含閘門坐落於水系之凹或凸岸、閘門上游側集水箱涵有無洩水坡度及海堤區、感潮河段閘門底檻高程與潮位之關係等閘門類型，以為閘門防淤、減淤研究，進一步分析的基礎。

The paper intends to establish the present conditions, such as the size, the outlet direction and the sidewall condition of river gates in each part of Taiwan by implementing whole investigations on the river gates under jurisdiction of every river management offices of the Water Resources Agency. The investigations were performed by gathering investigation reports from the river gate maintenance and management departments on the gates under their jurisdiction and obtaining information from the field operators of river gates. This paper uses the established conditions for analyzing probable causes of deposition in the proximity of tide gate. The causes presented by this paper can provide feasible advices for future planning of sand proof or reduction projects.
The common causes of gate outlet deposition are, for example, the placer deposition from rising tide, the deposition caused by topography and sediment characteristics, the deposition from upstream (inland) side of gates, the aeolian sand deposition, the sprawling plants deposition and the deposition of drifting or random objects. With the field investigation results, this paper divides Taiwan into northern, middle, southern and eastern part and respectively explains the characteristics of each part such as the number of river gates, the category (the gate with outlet facing rivers is called discharge or river gate in the following sections; the gate with outlet facing sea coast is called seawall gate in the following sections) to which the gate outlets belong, the degree and causes of deposition. The above explanations should help achieve better understanding of the similarities and differences between the causes of deposition of gates at respective parts of Taiwan.
By the investigations performed by this paper, the major cause of discharge and river gates deposition is surrounding topography and sediment characteristics (6%-25%) or sprawling plants (4%-65%); the deposition of seawall gates is mostly caused by sediments from rising tide (8%-27%), surrounding topography and bottom sediment (1%-5%) or crop branches and trunks drifted from upstream (1%-6%).
With the investigation results of gate deposition causes, this paper plans the design directions for gate outlet deposition proof and reduction. In the case of discharge and river gates, aquatic plants sprawling is contained with man or mechanic dredging, spraying herbicide and biological control; the side walls and gate outlet should have a small angle between each other for smooth sediment movement and river course stability. In the case of seawall gates, the direction of local sediment transport must be investigated before construction for reducing the effect of gate placer deposition on gate function; groins should be constructed at gate outlets for blocking placer deposition.
The corresponding data integrated by this paper can provide directions for researchers. This paper also proposes additional items for future field investigation: the gate location (at convex or concave bank), the existence of drainage slope of upstream catch culverts and the relationships between bottom threshold levels and tidal levels of seawall and tide reaching gates. These items lay the foundation of future analysis for researches on deposition proof and reduction.

1.交通部運輸研究所港灣技術研究中心(1999)，「屏東林邊沖淤調查研究」。
2.林信輝(2001)，水土保持植生工程，高立圖書有限公司。
3.施劍縈(1994)，「布袋蓮之生物防治」，苗栗區農業專訊。
4.施學銘、黃序文(1995)，「以重礦物為追蹤劑推論台灣西海岸之沿岸輸沙方向」，第17屆海洋工程研討會暨1995兩岸港口及海岸開發研討會論文集，頁1071-1084，臺南市，Nov. 09-10。
5.郭金棟(1999)，海岸工程，中國土木水利工程學會。
6.陳文俊、郭金棟(2005)，「台東海岸線變遷分析」，第27屆海洋工程研討會論文集，頁903-909，臺中市，Dec. 01-02。
7.許曛顯(2006)，「改善排水技術與對策之研究---以台中縣五甲溪流域為例」，逢甲大學土木工程學系碩士論文。
8.張燿東(2006)，「大安鄉北汕港改善需求之探討」，逢甲大學土木工程學系碩士論文。
9.經濟部水利署(2004-2010)，曾文溪水門維護、操作、管理委託技術服務計畫，惠民實業股份有限公司。
10.經濟部水利署(2007)，桃竹苗海堤水門漂砂淤積調查與防淤策略評估，京揚工程科技股份有限公司。
11.盧韋勳、江文山、溫進丁、謝錦志、林玉祥(2011)，「北門海岸及沙洲地形變遷」，第33屆海洋工程研討會論文集，頁423-428，高雄市，Dec. 01-02。
12.The New Jersey Meadowlands Commission. (2006)“ Hackensack Meadowlands Tide GatesInspection Report. ”.