tailieunhanh - Deterministic Methods in Systems Hydrology - Chapter 7

Mô hình đơn giản của dòng chảy dưới bề mặt chảy qua MEDIA xốp Trong Chương 5 và 6, chúng tôi đã quan tâm đến phân tích hộp đen và mô phỏng bằng mô hình khái niệm của các phản ứng cơn bão trực tiếp, tức là phần trả về nhanh chóng của các lưu vực để đáp ứng lượng mưa. Những khó khăn phát sinh trong cách tiếp cận đơn vị thuỷ văn liên quan đến baseflow và giảm có thể có mưa với lượng mưa có hiệu quả, phát sinh từ thực tế rằng các quá trình này. | CHAPTER 7 Simple Models of Subsurface Flow FLOW THROUGH POROUS MEDIA In Chapters 5 and 6 we have been concerned with the black box analysis and the simulation by conceptual models of the direct storm response . of the quick return portion of the catchment response to precipitation. The difficulties that arise in the unit hydrograph approach concerning the baseflow and the reduction of precipitation to effective precipitation arise from the fact that these processes are usually carried out without even postulating a crude model of what is happening in relation to soil moisture and Groundwater groundwater. Even the crudest model of subsurface flow would be an improvement on the classical arbitrary procedures for baseflow separation and computation of effective precipitation used in applied hydrology. It is desirable therefore for the study of floods as well as of low flow to consider the slower response which can be loosely identified with the passage of precipitation through the unsaturated zone and through the groundwater reservoir. In other words it is necessary to look at the remaining parts of the simplified catchment model given in Figure see page 19 . We approached the question of prediction of the direct storm response through the black-box approach in Chapter 4 and then considered the use of conceptual models as a development of this particular approach in Chapter 5. In the case of subsurface flow we will take the alternative approach of considering the equations of flow based on physical principles simplifying the equations that govern the phenomena of infiltration and groundwaterflow and finally developing lumped conceptual models based on these simplified equations. The basic physical principles governing subsurface flow can be found in the appropriate chapters of such references as Muskat 1937 Polubarinova-Kochina 1952 Luthin 1957 Harr 1962 De Wiest 1966 Bear and others 1968 Childs 1969 Eagleson 1969 Bear 1972 and others. The movement of water