利用GIS技術評估嘉義林區國有林對降水的年粗涵養量之研究

Using GIS Technique to Investigate the Annual Gross Quantity of the Forest Preserved Water with the Case of Chiayi Area

林金樹(Chin-Su Lin) ； 陳峰盛(Feng-Sheng Chen) ； 劉正川(Jeng-Chuan Liou)

《航測及遙測學刊》 7卷2期 (2002/06) Pp. 39-60

https://doi.org/10.6574/JPRS.2002.7(2).3

摘要

本研究以ArcGIS地理資訊系統為工具，依據經濟部水利局所轄的雨量與流量資料，以空間統計學方法分析推導嘉義林區全區的降雨量與年粗涵養量，目的在瞭解林區對降水的涵養能力，以供未來實施林區林地分級研究之應用。研究結果顯示，嘉義林區之阿里山、玉山、大埔以及玉井等四個事業區主要分佈於曾文溪、曾文水庫、荖濃溪、清水溪、旗山溪、陳有蘭溪、八掌溪以及急水溪等主要集水區內。在1999年當中，該等集水區每平方公尺單位面積的年平均降雨量在160 mm以上。阿里山、玉山、大埔以及玉井等四個事業區對1999年降雨的年粗涵養率各為38.61%、21.25%、31.70%以及65.81%。嘉義林區對降水的年粗涵養量具有波浪型態的變化特徵，在五月至八月的豐雨期間，森林或集水區對降水的年粗涵養量最高，隨著晚秋、冬季以致春季其年粗涵養量逐步下降，然後再向上升。

關鍵字

地理資訊系統 ； 降雨量 ； 粗涵養量 ； 克利金內插法 ； 空間統計學

並列摘要

This study applied the geostatistically ordinary Kriging algorithm to predict the spatially rainfall distribution of Chiayi forest area: It aims to know the rainfall amount that is annually kept by the forest area for purposes of forestland classification. Quantity of annually gross holdback (AGH) was defined by subtracting the discharge quantity from the rainfall. The data used in this study were supplied by the Water Resources Agency, Ministry of Economic Affairs; and were analyzed by the GIS software ArcGIS. Results showed that the Chaiyi forest area was wide located on several watersheds, such as Tseng-Wen Chi, Tseng-Wen Dam, Lao-Nung Chi, Ching-Chui Chi, Chi-San Chi, Cheng-You-Lan Chi, Pa-Chang Chi, and Chi-Shui Chi. In 1999, the mean annually rainfall of these watershed are more than 160 mm and the gross ratio of rainfall keeping of each working circle of Chaiyi forest area, i.e., Alishan, Yushan, Dapu, and Yuchin, is 38.61%, 21.25%, 31.70%, and 65.81% respectively. The AGH by the forest area and watershed is varying in a waveform corresponding with the serial month changing. Most of the positively AGH is happened from May to August, after that AGH is smoothly come down to negative until next May.

並列關鍵字

GIS ； Rainfall ； Gross holdback ； Kriging interpolation method ； Geostatistics