Storage-Reliability-Resilience-Yield Relations for Northeastern United States

Abstract

An evaluation of time-series of streamflow at 166 basins in the northeastern United States reveals that this region is remarkably homogeneous in terms of the year-to-year variability and persistence of average annual streamflow. Goodness-of-fit tests reveal that the 166 time-series of annual streamflow tested were well approximated by a lag-one normally distributed autoregressive process with a fixed lag-one correlation and a fixed coefficient of variation. Computer experiments revealed that the observed variability about these fixed values could easily arise from sampling alone, due to the varied and short records available. Recent research on the behavior of water supply systems reveals that simple analytic models can describe the general relationships among reservoir storage, yield, reliability, and resilience for systems dominated by overyear storage requirements. An analytic storage model is combined with the regional model of annual streamflow, resulting in general relations among storage, reliability, yield, and resilience useful for water supply systems in the Northeast. An example using the water supply systems for New York City, Boston, Providence, Rhode Island, and Springfield, Massachusetts, documents how the proposed methodology may be used to compare the behavior of four very different systems.