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A hydrograph is a graph showing the rate of flow (discharge) versus time past a specific point in a river, or other channel or conduit carrying flow. The rate of flow is typically expressed in cubic meters or cubic feet per second (cms or cfs). It can also refer to a graph showing the volume of water reaching a particular outfall, or location in a sewerage network, graphs are commonly used in the design of sewerage, more specifically, the design of surface water sewerage systems and combined sewers. ==Terminology== The discharge is measured at a specific point in a river and is typically time variant. *Rising limb: The rising limb of hydro graph, also known as concentration curve, reflects a prolonged increase in discharge from a catchment area, typically in response to a rainfall event *Recession (or falling) limb: The recession limb extends from the peak flow rate onward. The end of stormflow (aka quickflow or direct runoff) and the return to groundwater-derived flow (base flow) is often taken as the point of inflection of the recession limb. The recession limb represents the withdrawal of water from the storage built up in the basin during the earlier phases of the hydrograph. *Peak discharge: the highest point on the hydro graph when the rate of discharge is greatest *Lag time: the time interval from the center of mass of rainfall excess to the peak of the resulting hydrograph *Time to peak: time interval from the start of the resulting hydro graph *Discharge: the rate of flow (volume per unit time) passing a specific location in a river or other channel Types of hydrograph can include: *Storm hydrographs *Flood hydrographs *Annual hydrographs aka regimes *Direct Runoff Hydrograph *Effective Runoff Hydrograph *Raster Hydrograph *Storage opportunities in the drainage network (e.g., lakes, reservoirs, wetlands, channel and bank storage capacity) 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Hydrograph」の詳細全文を読む スポンサード リンク
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