Abstract
Recently the conscious to environment ascend, Land Improvement Act is revised. In this law, the maintenance technology considered against ecosystem is required. In this maintenance, at first the evaluation of agricultural canal as ecological environment is needed. In this study, against agricultural canal we aim the development of evaluation way for agricultural canal as ecological environment. For that, we consider agricultural canal as system, at first we make the fish ecological network map that evaluates the connection and interruption of agricultural canal. Secondly we divide agricultural canal system into system element and evaluate velocity and canal material. Thirdly we synthesize the system evaluation, the element evaluation and captured fish data, and make evaluation figure of fish ecological environment. Using this figure, we examine ecological environment of agricultural canal. The difference between upper basin and lower basin make climate condition and topography differ, so different fish habit in upper basin and lower basin. Besides agricultural canal system character is difference. It is important to compare upper basin and lower basin. We select Nyunomiya canal system as lower basin field and Tsujun canal as upper basin field. The evaluation figure shows that in system unit evaluation interruption of ecological network is main factor. Compared lower basin and upper basin, in lower basin water use facility is main factor of network interruption in upper basin drop and velocity is main factor. So we need different type provision in upper basin and lower basin. When we plan and design the maintenance considered ecological environment, at first we should watch agricultural canal as system, and consideration the network connection and habitat position. Secondly we watch system element and selection optimum constrictions that are fish block etc.
