Reviews on Base Flow Researches
基流研究综述

Base flow has important implications in water resources allocation, water security, food security, non point pollution assessment and investigation and water resource assessment. Base flow recession curves contain a lot of information related with hydro-settings. The paper first overviews the definitions of base flow. Then, base flow generation and loss mechanism and impact of hydrogeographical factors, rock kinds, climate condition, terrain, hydrologic condition and underlay ground were analyzed systematically. Impact of human activities, such as extraction of ground water, on different hydrogeographic settings, land use cover change (LUCC) and base flow was emphasized. Various kinds of base flow recession simulation methods, such as linear reservoir method, auto-regression simulation method, empirical function and method based on groundwater movement, were presented based on the characteristics of the basin; and the merits, demerits, and applied conditions of these function were illuminated. A series researches show non linear flow recession are more suitable than linear flow recession in recession simulation, which demonsfrates the non linear characteristics of out flow form aquifer. Base flow separation methods were reviewed. Above all, the water balance methods and the run-off simulation methods are sound based; but the graph method is subjective, which precision depends on ap-plier's knowledge on the relation between ground water and river. In addition, some comments on the construction of the recession function are stated.