The Application of Remote Sensing and Hydrological model on Water Conservation Capacity Estimation For Reservior Watershed Area
Tien- Yin Chou, Mei-Hsin Chen and Lung-Shin Yang
GIS Research Center, Feng Chin University
100 WENHWA RD., Taichung, Taiwan, R.O.C.
Tel : 886-4-4516669 FAX : 889-4-4519278.
E-mail: tychou@fcu.edu.tw
Abstract
The recent increased pressure on slope land development in Taiwan has changed the land use pattern in many reservoir watershed areas and affected the hydrologic cycle. These were many local researches examined this related issue, but none of that can fully describe the relationship between water conservation capacity and land use patterns in watershed area. This study is to integrate and analyze the impact to water conservation from deforestation or other land use pattern changes. Geographic Information System (GIS) were adopted to build a digital database for reservoir area and to process hydrologic analysis. Remote Sensing (RS) and Global Positioning System (GPS) were performed to extract and identify the surface vegetation details and land use changes information. By the assist of hydrologic model for water conservation capacity estimation from land use changes, the outcome of this study can provide an important reference for sound watershed management. This study identified the parameters to be used in heuristic HSPF model from waterguage station in Dapu Reservoir watershed. Four designed rainstorm simulation events were proved to fit the observed peak. The erosion estimation outcomes from Erosion Index Model (EIM) have been tested to correspond the tendency of higher erosion due to land use changes.
Introduction
The yearly average precipitation in Taiwan area is about 2510 mm, which is 2.6 timed over the world average value. But due to abundant of mountain area, vulnerable geological structure, steep topography, short and rush river flow, and inconsistent precipitation, the difficult in water storage and resources allocation reveals the importance of water conservation.
In recent years, the remarkable industrial business and economic development in Taiwan have enhanced the urgent demand for water resources. The recent increased pressure on slope land development has changed the land use pattern in man y reservoir watershed areas and affected the hydrologic cycle. Although there were many local researches examined this related issue, but none of that can describe the relationship between water conservation and land use pattern in watershed area.
In this research, Geographic Information System (GIS) were adopted to build database for reservoir area and to process hydrologic analysis. Remote Sensing (RS) and Global Positioning System (GPS) were performed to extract the surface vegetation details and land use change information. The final goal of this study is through the assist of hydrologic model for water conservation capacity estimation; the outcome can provide an important reference for watershed management.
Study Area
The study area for model application is Dar-Pu reservoir watershed with 10,000 hectare in area, which locates at the upper stream of E-Mei River with discharges through the north western of Taiwan. The original construction purpose for this reservoir was to provide irrigation supply for neighborhood irrigation at county level.
Figure 1. The Study Area - DaPu Reservoir Watershed Location Map
Research Procedure
This research consists four major parts: Hydrologic factors (parameter) analysis for water conservation capacity, Environmental database establishment for watershed area, hydrologic model evaluation and model analysis for research area.
The first part of this research was to determine those influenced the hydrological processes, which include water balance parameters extracted from various input data of hydrological model. Secondly. An environmentally sound database was built using GIS,RS and GPS technologies. Then choosing a suitable hydrologic model to best estimate the quantity of water conservation capacity. The last part to link the database with water conservation model and estimate the chares due to land use development.
