In simple words, base flow is the flow of water under the ground between the precipitation and percolation. If the precipitation and percolation act on base flow it is called a negative base flow. In this case, the base flow is below the line of the depletion curve. Negative base-flow is also called as bank storage.

It is also called as a draught flow or groundwater recession. The best floor is also called a fair-weather flow.

In civil engineering point of view, flow is very important for human population sustainability and balance in ecosystems.

Baseflow in the soil are depending upon the following factors:

1. Voids like micropores and macropores.
2. Conditions of fracture in soil
3. Some geomorphic conditions

Evapotranspiration is the main cause to reduce the base flow.

In negative base flow, the seepage of groundwater to the surface water for a very short period is reversed. The depletion curve is the recession curve, which is produced after the effect of groundwater seepage. And when the base flow is below the line of the depletion curve called a negative base flow.