集水區觀察員 Catchment Observer
地表逕流累積集水面積與水文風險評估工具 Rainfall Runoff Catchment Area & Hydrological Safety Assistant
利用內政部 20m DTM 數值高程模型，快速推估任意出水口的上游集水區面積，免去紙本數格子的不便。同時整合鄰近水位站、雨量站、流量站及地質敏感區資訊，是溪流戶外活動風險評估的利器。
Analyze catchment area sizes instantly using Taiwan's 20m DTM elevation model. Query neighboring water level, rainfall, flow rate, and geological alert stations to plan safe backcountry river trips.
集水區觀察員地圖工具 Interactive Catchment Map
點擊下方按鈕以全螢幕啟動地圖工具進行操作
Click the button below to launch the map tool in fullscreen mode
啟動集水區觀察員 (accTW) Launch Catchment Observer (accTW)
點擊後將直接加載地圖介面，您可以自由在地圖上點選任意溪流位置，即時估計該位置上游的總集水面積。 Click to load the interactive topographic map. Click any river coordinate to calculate upstream catchment area instantly.
超白話使用指南與安全判讀 Simple User Guide & Safety Decisions
如何用「大漏斗」概念來避開溪水暴漲風險？
How to use the funnel concept to assess swiftwater hazards
集水區就是收集雨水的「漏斗大小」 A Catchment Area is the Size of the Rain Funnel
當我們在野外活動（划船、溯溪、溪降或在溪邊紮營）時，你所在的溪流位置就是「漏斗的出水口」。
在這個位置上游的所有山谷、稜線所包圍的範圍，就是「集水區（漏斗的口）」。只要雨下在這個大漏斗的範圍內，所有的雨水最後都會匯集、流經你所在的位置。 When venturing outdoors (kayaking, river tracing, canyoning, or camping), your location on the river represents the "funnel's outlet".
All the ridgelines and valleys upstream comprise the "catchment basin (the funnel's opening)". Any precipitation falling within this funnel will inevitably drain past your position.
💡 地圖上的「藍色圓圈」代表什麼？ 💡 What Does the Blue Circle Represent?
當你在地圖上點選一個點，工具會自動算出這個點的上游漏斗有多大（集水面積），並在地圖上畫出一個面積完全對等的藍色圓圈。藍色圓圈越大，代表上游收集雨水的漏斗越大，水量暴漲的潛在威脅就越驚人！ When you click a coordinate, the tool computes upstream drainage area and draws an equivalent-area blue circle on the map. A larger circle denotes a larger drainage funnel, indicating a much greater risk of sudden, destructive flash flooding!
如何三步完成評估？ Three-Step Assessment Guide
- 定位點擊 Locate & Click ： 打開地圖，放大並點選你的活動終點、下水點或預定營地。 Open the map, zoom in, and click your takeout, put-in, or campsite location.
- 觀察藍圈 Inspect Circle Size ：
看地圖上產生的藍色圓圈。例如顯示
23 km²，表示上游漏斗面積為 23 平方公里。 Observe the resulting blue circle. A readout of23 km²means the upstream funnel spans 23 square kilometers. - 結合監測資訊 Cross-Reference Gauges ： 點擊藍圈或右側選單，可以直接查詢鄰近雨量站、水位站的即時數據，確認漏斗範圍內是否正在下雨。 Click the circle or sidebar to query nearby real-time rain and streamflow gauges to see if rain is falling within the catchment.
野外溪流實戰應用範例 Real-World Field Applications & Case Studies
一、避開「高集水區」大溪谷的致命山洪 1. Avoiding Fatal Flash Floods in High-Catchment Valleys
場景：規劃在某條中海拔野溪溯溪並紮營兩天一夜。
操作：在地圖預定營地位置點一下，顯示集水面積為 80 km²（超大型漏斗）。這代表即使營地目前出太陽，只要上游數十公里外的源頭山區下起局部雷陣雨，營地所在的溪谷隨時會爆發毀滅性山洪。
決策：放棄在主流溪谷紮營。改為尋找匯入該主流的側邊小支流（點擊顯示集水面積僅 < 5 km²），小支流的漏斗小，即使下雨，其溪水暴漲的總量與流速都在安全撤退與應變的可控範圍內。 Scenario: Planning an overnight river tracing trip in a mid-altitude alpine canyon.
Action: Clicking the proposed campsite reveals a catchment of 80 km² (a massive funnel). Even with blue skies at camp, isolated thunderstorms 20 km upstream in headwater mountains can trigger sudden flash floods.
Decision: Abandon main-stem riverbed camping. Relocate to a side tributary with catchment area < 5 km², where runoff volume and flood surge peaks remain manageable for evacuation.
二、結合雨量預估，粗算溪流逕流水量 2. Estimating Surface Runoff Volumes from Rain Forecasts
場景：準備下航某條中級激流河段，想評估水量是否過大。
操作：在預計下水點選取，顯示集水區面積 A = 110 km²。氣象局預報該區 12 小時累積降雨量 P = 50 mm (0.05 m)。
粗算公式：總水體體積 V = A × P × C（C 為山區逕流係數，取常規之 0.8）
V = 110,000,000 m² × 0.05 m × 0.8 = 4,400,000 m³
這代表將有高達 440 萬噸的降雨直接轉為地表逕流匯入河道。
決策：如此龐大的水量將顯著改變主流水理特性（流速激增、捲揚力強、回水區消失）。若隊伍整體的實質划行技術、障礙物迴避與現場救援能力不足以應對暴漲後的水位，應果斷取消下航，或轉移至集水區極小、具備隨時上岸撤退腹地、容錯率高的避風港河段。 Scenario: Planning to run an intermediate whitewater river and assessing runoff hazard.
Action: Clicking the put-in displays catchment area A = 110 km². Forecast predicts 12-hour accumulated rainfall P = 50 mm (0.05 m).
Estimation Formula: Total Runoff Volume V = A × P × C (mountain runoff coefficient C ≈ 0.8)
V = 110,000,000 m² × 0.05 m × 0.8 = 4,400,000 m³ (4.4 million cubic meters of floodwater entering the gorge).
Decision: This surge radically alters hydraulic dynamics (extreme velocity, violent recirculations, washed-out eddies). Unless the team possesses expert boat control and high-water rescue proficiency, abort the run or divert to a small-catchment run with forgiving scouting banks.
作者介紹 About the Author
wiwari
開源專案創作者 / 開發者 Open Source Creator & Developer
GitHub 帳號為 wiwari，是開源水文評估工具「集水區觀察員 (accTW)」的作者與主要開發者。 wiwari is the author and primary developer of the open-source hydrological evaluation tool "Catchment Observer (accTW)" on GitHub.
致力於將開放資料與地形模型整合，提供戶外活動愛好者便利的數位分析工具，以提升溪流活動的風險評估效率。 Dedicated to integrating open geospatial data and digital elevation models, empowering outdoor adventurers with accessible analytical tools for river safety.
核心設計原理與資料出處 Principles & Data Sources
1. 數值高程地形推估 (DTM Calculations) 1. 20m DTM Elevation Modeling
系統基於內政部地政司釋出之全台 20 公尺數值地形模型 (20m DTM) 開放資料。透過水文分析（Flow Direction / Flow Accumulation），預先計算出全台地表每一網格點所承受的累積上游網格數，以此即時推估地表任意點的總集水面積。 Built on Taiwan MOI's open 20m Digital Terrain Model (DTM). Through Flow Direction and Flow Accumulation raster algorithms, upstream cell accumulation is pre-computed for every grid cell across Taiwan to evaluate total drainage area instantaneously.
2. 水文三級監測站動態查詢 2. Real-Time Multi-Tier Hydrology Feeds
當使用者點選集水區圓形後，系統會動態比對當前出水口位置與環境部、水利署、氣象署資料庫，拉取鄰近的「水位觀測站」、「雨量觀測站」、「流量監測站」及「地質敏感區（崩塌、土石流預警）」資訊，實現一站式環境安全評估。 When a catchment is selected, the tool dynamically cross-references MOENV, WRA, and CWA databases to query nearby streamflow, rainfall, water level gauges, and geological landslide alert zones.
原創授權與引用聲明 Attributions & Open Licensing
本頁面收錄之「超白話使用指南與安全判讀」為王汪汪根據 wiwari 的 GitHub 專案與公開論述整理撰寫而成。 The "Simple User Guide & Safety Decisions" featured on this page was compiled and written by Wang Wang-Wang based on wiwari's open-source project and publications.
內容依 CC BY-NC-SA 4.0 (姓名標示-非商業性-相同方式分享 4.0 國際) 授權釋出。互動式地圖軟體原始碼開源於 GitHub 專案。 Content is licensed under CC BY-NC-SA 4.0. Map application source code is openly hosted on GitHub.