圖書典藏及影音數位平台

河川為全民寶貴的資產，河川的開發利用，從過去單純的灌溉供水、農業生產、農村需求等逐漸演變到休閒遊憩、景觀與環境生態等。隨著經濟發展及社會的變遷，河川區域內之使用行為也日趨複雜，以本署各河川局有限之人力欲有效監控河川區域內違法之行為，有其實際之困難，尤其盜濫採砂石、毀損河防建造物、棄置廢土廢棄物等動態違規行為，更加困難。另中央管河川區域內違法行為一般係由轄管河川局巡防人員於查獲當時告發，唯因河川區域內地形地貌常隨水位變易產生極大之變化，或因缺乏客觀事實之比對，導致相關執法人員與違法行為者發生極多之衝突，亦對河川局執行取締業務產生諸多困擾。 爰此，如何透過一套完善的監測機制，以客觀、有效的方法掌握河川區域內地形地貌的現況及變遷的資訊，遂成為提昇河川管理成效重要的課題之一。近年來，由於遙測技術具有大地區的空間涵蓋特性，可以提供詳實且長時間的紀錄，並具有極佳的觀察能力，是快速獲取全面性最新國土資訊的調查及監測工具。尤其是93年5月21日我國自主衛星華衛二號成功發射之後，華衛二號衛星影像以其具有自主性高、影像解析度高、資料獲取週期短、價格較便宜等特性，可用以迅速掌握地表改變狀況以做為全面性的土地利用監測工具。 本計畫將引入此一先進而成熟的遙測科學技術對中央管河川（含淡水河及磺溪水系）流域進行長期的監測，期望藉由其高時效與大範圍監測的特性，週期性地進行河川區域內之監測，並針對每一前、後期的遙測監測資料進行比對，將發現有異之區域分析結果，透過網路通報機制提供本署各河川局該變異點的座標及現場查證的相關輔助圖資，俾利進行實地的查核，減少河川局第一線工作同仁巡防取締之工作人力及壓力，提高河川巡防取締及管理成效並落實現代化之河川管理。

The illegal land-use of river area has been becoming complicated and serious recently. It appears the monitoring of whole river area will be extremely difficult if the task is carried out by the limited human resource. The purpose of this project is to use remote sensing satellite images to regularly detect the change spots of the land use in river area. Firstly, the automatic change detection algorithm is implemented by using temporal satellite images. Then the manual interpretation procedure is involved to select the change spots with high possibility of illegal use. Then, the change information will be delivered to the local patrol units via internet. The change spots are required to perform the field investigation in a period of two weeks. Thereafter, the investigation results and the field photos will be uploaded and integrated into the web-based database management system. The project is carried out from 6 May 2010 to 5 Sep 2011. Since the monitoring is implemented on the basis of two weeks, there are 28 change spot notifications and investigations are completed and 896 change spots are detected until 7 July 2011. In the project, the major image sources are obtained from FORMOSAT-2 with the occasional use of SPOT5 images. Therefore, the amount of the images not only provides the total coverage over the study areas, but also keeps the project management on schedule. There are 26 emergency cases requested from Water Resources Agency during the project period and the satellite images as well as the related analysis are able to provide the valuable information for various situations. Meanwhile, it is essential to collect 102 cases of illegal sandstone quarrying and relate them to the spectral and texture characteristics of the satellite images. In addition, the illegal sandstone quarrying is spatially analyzed with the GIS data layers of roads and embankments. The analysis is able to provide the spectral and spatial correlations between the illegal sandstone quarrying and the satellite images as well as the GIS data layers. In the purpose of the river patrol mission, Viewshed analysis is experimentally performed to optimize the observation points on the road in order to save the time and resource. The results of the project indicate that the regular detection of the changes in the river areas from the temporal satellite images is able to assist the river patrol mission and manage the lands of river bank in an efficient way.