Hydrologic Sampling: A Characterization in Terms of Rainfall and Basin Properties

This paper considers the sampling of rainfall and discharge processes both in time and in space and links the sampling problem to basin and rainfall characteristics. The effectiveness of different sampling strategies is measured by the variance of the error in estimating either total or peak of streamflow from a single storm event. This is related to the rainfall and basin rainfall-discharge properties through parameterizations of these processes. Rainfall is modeled as a collection of rain cells which occur randomly in space and time and has parameters which define the probability of occurrence of rain cells in space and time and the spread of rainfall due to a cell. Discharge from rainfall is parameterized in terms of the fluvial geomorphology of the basin. Linear filtering techniques are used to compute the variance of the estimation error for different sampling strategies. Sampling strategies are defined by the number of rain gages, rainfall sampling interval and discharge measurement interval. The results can be used in hydrologic network design to assess the effectiveness of different sampling options