Hydrograph Analysis in a Fractured Rock Terrane

A typical watershed near Oak Ridge, Tennessee is underlaid by a stormflow zone, which approximately corresponds with the root zone of vegetation, and by a ground‐water zone. Analysis of the streamflow hydrograph and water‐level hydrographs during the nongrowing season shows that discharge from the stormflow zone constitutes nearly all streamflow after the end of overland runoff but that discharge from the ground‐water zone is dominant after about 8–10 d (days) of recession. Simple equations that express the relationship between streamflow recession and storage depletion can be used to calculate average values of specific yield, transmissivity, and hydraulic conductivity in both the stormflow and ground‐water zones. The calculated values are reasonable and are nearly the same as those obtained by other methods.