Thủy văn là có liên quan với tất cả các giai đoạn của việc vận chuyển nước giữa khí quyển, bề mặt đất và dưới bề mặt, và các đại dương, và sự phát triển lịch sử của một sự hiểu biết của quá trình thủy văn của riêng mình một hấp dẫn Như một khoa học, thuỷ văn bao gồm nhiều quá trình phức tạp, một số trong đó chỉ được hiểu hoàn toàn. Nó có lẽ là hữu ích trong việc phát triển một sự hiểu biết của lý thuyết thủy văn để tập trung sự chú. | HYDROLOGY THE PURPOSES OF HYDROLOGICAL STUDIES Hydrology is concerned with all phases of the transport of water between the atmosphere the land surface and subsurface and the oceans and the historical development of an understanding of the hydrological process is in itself a fascinating As a science hydrology encompasses many complex processes a number of which are only imperfectly understood. It is perhaps helpful in developing an understanding of hydrological theory to focus attention not on the individual physical processes but on the practical problems which the hydrologist is seeking to solve. By studying hydrology from the problem-solving viewpoint we shall see the interrelationship of the physical processes and the approximations which are made to represent processes which are either imperfectly understood or too complex for complete physical representation. We shall also see what data is required to make adequate evaluations of given problems. A prime hydrological problem is the forecasting of stream-flow run-off. Such forecasts may be concerned with daily flows especially peak flows for flood warning or a seasonal forecast may be required where a knowledge of the total volume of run-off is of prime interest. More sophisticated forecast procedures are required for the day-to-day operation of flood control reservoirs hydropower projects irrigation and water supply schemes especially for schemes which are used to serve several purposes simultaneously such as hydropower flood control and irrigation. Hydrologists are also concerned with studying statistical patterns of run-off. A special class of problems is the study of extreme events such as floods or droughts. Such maximum events provide limiting design data for flood spillways dyke levels channel design etc. Minimum events are important for example in irrigation studies and fisheries projects. A more complex example of statistical studies is concerned with sequential patterns of run-off for either .
