An integrated drainage network analysis system for agricultural drainage management. Part 1: the system

This is the first of two papers that elaborate an integrated drainage network analysis system (IDNAS) for agricultural drainage management. In this paper, the system components, functions and implementation are presented. The IDNAS comprises an agricultural drainage network module, an evapotranspiration (ET) module and an event-based spatio-temporal module. The network module is designed to model a typical agricultural drainage system and to perform the specific tasks for network assessment, monitoring and simulation in a geographical information system (GIS). The ET module is used to estimate real-time evapotranspiration from remotely sensed imagery and to update the water balance model. The spatio-temporal module comprises a computer watertable simulation model and routines providing linkage between event data and GIS thematic layer for event-based analysis. Specialized data processing routines have been developed to link the network data model with temporal hydrological modeling to allow computation of important network parameters such as flow travel time, discharge and capacity, and to dynamically simulate drainage response to individual rainfall events. A common interface has been developed to link those components, and to interact with the users. The Arc/Info GIS was used for the system implementation. With those components and functions, the system is well suited for assessment and management of agricultural drainage systems. In the second paper, case studies are presented which show how the system can be used for efficient agricultural drainage management, such as drainage capacity assessment, discharge computation, and event-based acid drainage evaluation and management.