Model Type: Geomorphologic Analysis and Rainfall-Runoff Model
Model Name: Water Resource Application Planning System
Introduction
Water conservation work is comparatively difficult in Taiwan because the island suffers from an uneven distribution of rainfall, coupled with the rapid current of the rivers. Moreover, severe floods and droughts seem more frequent than before, and the water demand in urban areas continues growing. This has resulted in an urgent need to explore extra water resources to solve the water shortage problem. Since providing required information for a water resource facility is a time-consuming task, developing an efficient way for integrated geomorphologic and hydrological analyses is considered important. There are a total of 22 river basins included in the information platform in the 3-year (2015–2017) project. All the river basin systems were integrated on an open-source GIS platform to meet the requirements of preliminary planning work for a new water resource development project.
In performing a water resources planning project, engineers often face the challenge of limited hydrological records for analysis. For this reason, geomorphology-based runoff models were adopted for flow analysis. The information system can provide long-term simulations at any target location for runoff analysis. TOPMODEL is used for daily-flow simulations, and then the daily-flow series are accumulated to obtain the ten-day flow series for further flow exceedance probability analysis and ecological base flow estimation. Considering the large amount of geomorphologic factors required in performing the hydrological simulations, the system adopted a digital elevation model (DEM) for watershed geomorphologic factors calculation.
An open-source geographic information system (open-source GIS) was adopted in this project to build the information platform and integrate the watershed geomorphologic and hydrological analysis modules. The operating functions of the platform include a Water Resources Database, Pre-set Menu, Rainfall Analysis Module, Runoff Analysis Module, Reservoir Analysis Module, Water Resources Analysis Module, Spatial Analysis Module, Probable Maximum Flood (PMF) Analysis Module, Result Demonstration Module, and Updating Function.
The Water Resources Database allows users to view and edit hydrologic data, average temperature data, and water usage information. The Pre-set Menu can calculate watershed geomorphologic factors at any target location in the stream network (Figure 1), select storm events for analysis, and assign hydrological model parameters. The Rainfall Analysis Module includes rainfall frequency analysis, rainfall intensity-duration-frequency analysis, spatial average rainfall estimation, and the probability analysis of consecutive dry days and workable days. The Runoff Analysis Module includes flow frequency analysis, peak-flow return period analysis, daily flow simulation, and exceedance probability analysis. The Reservoir Analysis Module was developed for estimating the reservoir height-area-volume curve (H-A-V curve), suspended-sediment rating curve analysis, and reservoir life analysis. The Water Resources Analysis Module is used to analyze the relationship between the target location and water usage information, the residual flow at the target location considering daily flow, and reservoir water supply capacity. The Spatial Analysis Module was developed to measure the impact of the reservoir on the environment and for shallow landslide analysis. The PMF Analysis Module includes probable maximum precipitation (PMP) analysis and probable maximum flood (PMF) analysis.
The main window of the Water Resource Application Planning System platform is shown in Figure 2. The platform integrates geomorphologic and hydrological calculation functions for available water analysis. This integrated platform provides a convenient way for engineers to obtain most of the required information while performing water resources planning and design work.
Figure 1. By selecting the analysis control point coordinates with the mouse, geomorphological factors for any location on the river network can be determined.
Figure 2. Main window of Water Resource Application Planning System