Stream Flow

Stream flow is a fundamental property that affects channel shape and the diversity of stream habitats, the flux of nutrients and pollutants, and the frequency and severity of floods. Stream flow is controlled by such watershed variables as size, topography, geology, land use and presence of wetlands, as well as climatic variables such as rainfall, snow cover and temeprature.

Two important concepts in the analysis of stream flow are:

1. stage (also called gage height or water level, which is the elevation of the stream surface relative to some fixed reference point, or datum;
2. discharge, which is the volumetric flow rate of the stream, commonly expressed in cubic feet per second or cubic meters per second

As explained below, stage is relatively quick and easy to measure, whereas discharge measurements are more time consuming and may involve specialized equipment. Because of this, a rating curve--a graphical or mathematical relationship between stage and discharge--is commonly constructed in order to produce discharge estimates from stage readings.

Nequasset Stream at low flow

Nequasset Stream at high flow